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TCAN4550: 芯片的应用问题

Part Number: TCAN4550


有没有安卓平台的驱动,目前的代码差异比较大,需要安卓平台的驱动

  • 已经知道只有C语言和Linux的驱动,麻烦给一下.

    另外如果要安卓的驱动程序,正常工作需要下哪些寄存器以及完整的上下电时许麻烦说明一下,谢谢!

  • 您好,关于TCAN4550 驱动的帖子很多,包括您说的linux或者C:

    https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1213252/tcan4550-tcan4550-linux-driver-support/4578731#4578731

    https://e2e.ti.com/support/interface-group/interface/f/interface-forum/808025/linux-tcan4550-linux-driver-for-tcan4550

    https://e2e.ti.com/support/interface-group/interface/f/interface-forum/841680/tcan4550-linux-driver-for-tcan4550

    但是没有找到关于安卓的驱动。

    关于上掉电时序,建议参考datasheet Figure 15-18的时序图,包括上电时序,normal to sleep 或者sleep to standby的时序要求。

    硬件上如果有什么问题,我们可一起讨论。

    https://www.ti.com/lit/ds/symlink/tcan4550.pdf

  • 安卓的驱动能不能参考其他家的IC代码修改一下,只改寄存器相关的内容?我这边自己写太耗时间了,因为对IC的寄存器配置部分也不太熟悉。需要原厂处理IC的部分,我这边只处理平台部分.下面发的驱动也是安卓自带别家的IC的驱动,也是SPI的.

    /* CAN bus driver for Holt HI3110 CAN Controller with SPI Interface
     *
     * Copyright(C) Timesys Corporation 2016
     *
     * Based on Microchip 251x CAN Controller (mcp251x) Linux kernel driver
     * Copyright 2009 Christian Pellegrin EVOL S.r.l.
     * Copyright 2007 Raymarine UK, Ltd. All Rights Reserved.
     * Copyright 2006 Arcom Control Systems Ltd.
     *
     * Based on CAN bus driver for the CCAN controller written by
     * - Sascha Hauer, Marc Kleine-Budde, Pengutronix
     * - Simon Kallweit, intefo AG
     * Copyright 2007
     *
     * This program is free software; you can redistribute it and/or modify
     * it under the terms of the GNU General Public License version 2 as
     * published by the Free Software Foundation.
     */
    
    #include <linux/can/core.h>
    #include <linux/can/dev.h>
    #include <linux/can/led.h>
    #include <linux/clk.h>
    #include <linux/completion.h>
    #include <linux/delay.h>
    #include <linux/device.h>
    #include <linux/dma-mapping.h>
    #include <linux/freezer.h>
    #include <linux/interrupt.h>
    #include <linux/io.h>
    #include <linux/kernel.h>
    #include <linux/module.h>
    #include <linux/netdevice.h>
    #include <linux/of.h>
    #include <linux/of_device.h>
    #include <linux/platform_device.h>
    #include <linux/regulator/consumer.h>
    #include <linux/slab.h>
    #include <linux/spi/spi.h>
    #include <linux/uaccess.h>
    
    #define HI3110_MASTER_RESET 0x56
    #define HI3110_READ_CTRL0 0xD2
    #define HI3110_READ_CTRL1 0xD4
    #define HI3110_READ_STATF 0xE2
    #define HI3110_WRITE_CTRL0 0x14
    #define HI3110_WRITE_CTRL1 0x16
    #define HI3110_WRITE_INTE 0x1C
    #define HI3110_WRITE_BTR0 0x18
    #define HI3110_WRITE_BTR1 0x1A
    #define HI3110_READ_BTR0 0xD6
    #define HI3110_READ_BTR1 0xD8
    #define HI3110_READ_INTF 0xDE
    #define HI3110_READ_ERR 0xDC
    #define HI3110_READ_FIFO_WOTIME 0x48
    #define HI3110_WRITE_FIFO 0x12
    #define HI3110_READ_MESSTAT 0xDA
    #define HI3110_READ_REC 0xEA
    #define HI3110_READ_TEC 0xEC
    
    #define HI3110_CTRL0_MODE_MASK (7 << 5)
    #define HI3110_CTRL0_NORMAL_MODE (0 << 5)
    #define HI3110_CTRL0_LOOPBACK_MODE (1 << 5)
    #define HI3110_CTRL0_MONITOR_MODE (2 << 5)
    #define HI3110_CTRL0_SLEEP_MODE (3 << 5)
    #define HI3110_CTRL0_INIT_MODE (4 << 5)
    
    #define HI3110_CTRL1_TXEN BIT(7)
    
    #define HI3110_INT_RXTMP BIT(7)
    #define HI3110_INT_RXFIFO BIT(6)
    #define HI3110_INT_TXCPLT BIT(5)
    #define HI3110_INT_BUSERR BIT(4)
    #define HI3110_INT_MCHG BIT(3)
    #define HI3110_INT_WAKEUP BIT(2)
    #define HI3110_INT_F1MESS BIT(1)
    #define HI3110_INT_F0MESS BIT(0)
    
    #define HI3110_ERR_BUSOFF BIT(7)
    #define HI3110_ERR_TXERRP BIT(6)
    #define HI3110_ERR_RXERRP BIT(5)
    #define HI3110_ERR_BITERR BIT(4)
    #define HI3110_ERR_FRMERR BIT(3)
    #define HI3110_ERR_CRCERR BIT(2)
    #define HI3110_ERR_ACKERR BIT(1)
    #define HI3110_ERR_STUFERR BIT(0)
    #define HI3110_ERR_PROTOCOL_MASK (0x1F)
    #define HI3110_ERR_PASSIVE_MASK (0x60)
    
    #define HI3110_STAT_RXFMTY BIT(1)
    #define HI3110_STAT_BUSOFF BIT(2)
    #define HI3110_STAT_ERRP BIT(3)
    #define HI3110_STAT_ERRW BIT(4)
    #define HI3110_STAT_TXMTY BIT(7)
    
    #define HI3110_BTR0_SJW_SHIFT 6
    #define HI3110_BTR0_BRP_SHIFT 0
    
    #define HI3110_BTR1_SAMP_3PERBIT (1 << 7)
    #define HI3110_BTR1_SAMP_1PERBIT (0 << 7)
    #define HI3110_BTR1_TSEG2_SHIFT 4
    #define HI3110_BTR1_TSEG1_SHIFT 0
    
    #define HI3110_FIFO_WOTIME_TAG_OFF 0
    #define HI3110_FIFO_WOTIME_ID_OFF 1
    #define HI3110_FIFO_WOTIME_DLC_OFF 5
    #define HI3110_FIFO_WOTIME_DAT_OFF 6
    
    #define HI3110_FIFO_WOTIME_TAG_IDE BIT(7)
    #define HI3110_FIFO_WOTIME_ID_RTR BIT(0)
    
    #define HI3110_FIFO_TAG_OFF 0
    #define HI3110_FIFO_ID_OFF 1
    #define HI3110_FIFO_STD_DLC_OFF 3
    #define HI3110_FIFO_STD_DATA_OFF 4
    #define HI3110_FIFO_EXT_DLC_OFF 5
    #define HI3110_FIFO_EXT_DATA_OFF 6
    
    #define HI3110_CAN_MAX_DATA_LEN 8
    #define HI3110_RX_BUF_LEN 15
    #define HI3110_TX_STD_BUF_LEN 12
    #define HI3110_TX_EXT_BUF_LEN 14
    #define HI3110_CAN_FRAME_MAX_BITS 128
    #define HI3110_EFF_FLAGS 0x18 /* IDE + SRR */
    
    #define HI3110_TX_ECHO_SKB_MAX 1
    
    #define HI3110_OST_DELAY_MS (10)
    
    #define DEVICE_NAME "hi3110"
    
    static int hi3110_enable_dma = 1; /* Enable SPI DMA. Default: 1 (On) */
    module_param(hi3110_enable_dma, int, 0444);
    MODULE_PARM_DESC(hi3110_enable_dma, "Enable SPI DMA. Default: 1 (On)");
    
    static const struct can_bittiming_const hi3110_bittiming_const = {
    	.name = DEVICE_NAME,
    	.tseg1_min = 2,
    	.tseg1_max = 16,
    	.tseg2_min = 2,
    	.tseg2_max = 8,
    	.sjw_max = 4,
    	.brp_min = 1,
    	.brp_max = 64,
    	.brp_inc = 1,
    };
    
    enum hi3110_model {
    	CAN_HI3110_HI3110 = 0x3110,
    };
    
    struct hi3110_priv {
    	struct can_priv can;
    	struct net_device *net;
    	struct spi_device *spi;
    	enum hi3110_model model;
    
    	struct mutex hi3110_lock; /* SPI device lock */
    
    	u8 *spi_tx_buf;
    	u8 *spi_rx_buf;
    	dma_addr_t spi_tx_dma;
    	dma_addr_t spi_rx_dma;
    
    	struct sk_buff *tx_skb;
    	int tx_len;
    
    	struct workqueue_struct *wq;
    	struct work_struct tx_work;
    	struct work_struct restart_work;
    
    	int force_quit;
    	int after_suspend;
    #define HI3110_AFTER_SUSPEND_UP 1
    #define HI3110_AFTER_SUSPEND_DOWN 2
    #define HI3110_AFTER_SUSPEND_POWER 4
    #define HI3110_AFTER_SUSPEND_RESTART 8
    	int restart_tx;
    	struct regulator *power;
    	struct regulator *transceiver;
    	struct clk *clk;
    };
    
    static void hi3110_clean(struct net_device *net)
    {
    	struct hi3110_priv *priv = netdev_priv(net);
    
    	if (priv->tx_skb || priv->tx_len)
    		net->stats.tx_errors++;
    	if (priv->tx_skb)
    		dev_kfree_skb(priv->tx_skb);
    	if (priv->tx_len)
    		can_free_echo_skb(priv->net, 0);
    	priv->tx_skb = NULL;
    	priv->tx_len = 0;
    }
    
    /* Note about handling of error return of hi3110_spi_trans: accessing
     * registers via SPI is not really different conceptually than using
     * normal I/O assembler instructions, although it's much more
     * complicated from a practical POV. So it's not advisable to always
     * check the return value of this function. Imagine that every
     * read{b,l}, write{b,l} and friends would be bracketed in "if ( < 0)
     * error();", it would be a great mess (well there are some situation
     * when exception handling C++ like could be useful after all). So we
     * just check that transfers are OK at the beginning of our
     * conversation with the chip and to avoid doing really nasty things
     * (like injecting bogus packets in the network stack).
     */
    static int hi3110_spi_trans(struct spi_device *spi, int len)
    {
    	struct hi3110_priv *priv = spi_get_drvdata(spi);
    	struct spi_transfer t = {
    		.tx_buf = priv->spi_tx_buf,
    		.rx_buf = priv->spi_rx_buf,
    		.len = len,
    		.cs_change = 0,
    	};
    	struct spi_message m;
    	int ret;
    
    	spi_message_init(&m);
    
    	if (hi3110_enable_dma) {
    		t.tx_dma = priv->spi_tx_dma;
    		t.rx_dma = priv->spi_rx_dma;
    		m.is_dma_mapped = 1;
    	}
    
    	spi_message_add_tail(&t, &m);
    
    	ret = spi_sync(spi, &m);
    
    	if (ret)
    		dev_err(&spi->dev, "spi transfer failed: ret = %d\n", ret);
    	return ret;
    }
    
    static u8 hi3110_cmd(struct spi_device *spi, u8 command)
    {
    	struct hi3110_priv *priv = spi_get_drvdata(spi);
    
    	priv->spi_tx_buf[0] = command;
    	dev_dbg(&spi->dev, "hi3110_cmd: %02X\n", command);
    
    	return hi3110_spi_trans(spi, 1);
    }
    
    static u8 hi3110_read(struct spi_device *spi, u8 command)
    {
    	struct hi3110_priv *priv = spi_get_drvdata(spi);
    	u8 val = 0;
    
    	priv->spi_tx_buf[0] = command;
    	hi3110_spi_trans(spi, 2);
    	val = priv->spi_rx_buf[1];
    
    	return val;
    }
    
    static void hi3110_write(struct spi_device *spi, u8 reg, u8 val)
    {
    	struct hi3110_priv *priv = spi_get_drvdata(spi);
    
    	priv->spi_tx_buf[0] = reg;
    	priv->spi_tx_buf[1] = val;
    	hi3110_spi_trans(spi, 2);
    }
    
    static void hi3110_hw_tx_frame(struct spi_device *spi, u8 *buf, int len)
    {
    	struct hi3110_priv *priv = spi_get_drvdata(spi);
    
    	priv->spi_tx_buf[0] = HI3110_WRITE_FIFO;
    	memcpy(priv->spi_tx_buf + 1, buf, len);
    	hi3110_spi_trans(spi, len + 1);
    }
    
    static void hi3110_hw_tx(struct spi_device *spi, struct can_frame *frame)
    {
    	u8 buf[HI3110_TX_EXT_BUF_LEN];
    
    	buf[HI3110_FIFO_TAG_OFF] = 0;
    
    	if (frame->can_id & CAN_EFF_FLAG) {
    		/* Extended frame */
    		buf[HI3110_FIFO_ID_OFF] = (frame->can_id & CAN_EFF_MASK) >> 21;
    		buf[HI3110_FIFO_ID_OFF + 1] =
    			(((frame->can_id & CAN_EFF_MASK) >> 13) & 0xe0) |
    			HI3110_EFF_FLAGS |
    			(((frame->can_id & CAN_EFF_MASK) >> 15) & 0x07);
    		buf[HI3110_FIFO_ID_OFF + 2] =
    			(frame->can_id & CAN_EFF_MASK) >> 7;
    		buf[HI3110_FIFO_ID_OFF + 3] =
    			((frame->can_id & CAN_EFF_MASK) << 1) |
    			((frame->can_id & CAN_RTR_FLAG) ? 1 : 0);
    
    		buf[HI3110_FIFO_EXT_DLC_OFF] = frame->can_dlc;
    
    		memcpy(buf + HI3110_FIFO_EXT_DATA_OFF,
    		       frame->data, frame->can_dlc);
    
    		hi3110_hw_tx_frame(spi, buf, HI3110_TX_EXT_BUF_LEN -
    				   (HI3110_CAN_MAX_DATA_LEN - frame->can_dlc));
    	} else {
    		/* Standard frame */
    		buf[HI3110_FIFO_ID_OFF] =   (frame->can_id & CAN_SFF_MASK) >> 3;
    		buf[HI3110_FIFO_ID_OFF + 1] =
    			((frame->can_id & CAN_SFF_MASK) << 5) |
    			((frame->can_id & CAN_RTR_FLAG) ? (1 << 4) : 0);
    
    		buf[HI3110_FIFO_STD_DLC_OFF] = frame->can_dlc;
    
    		memcpy(buf + HI3110_FIFO_STD_DATA_OFF,
    		       frame->data, frame->can_dlc);
    
    		hi3110_hw_tx_frame(spi, buf, HI3110_TX_STD_BUF_LEN -
    				   (HI3110_CAN_MAX_DATA_LEN - frame->can_dlc));
    	}
    }
    
    static void hi3110_hw_rx_frame(struct spi_device *spi, u8 *buf)
    {
    	struct hi3110_priv *priv = spi_get_drvdata(spi);
    
    	priv->spi_tx_buf[0] = HI3110_READ_FIFO_WOTIME;
    	hi3110_spi_trans(spi, HI3110_RX_BUF_LEN);
    	memcpy(buf, priv->spi_rx_buf + 1, HI3110_RX_BUF_LEN - 1);
    }
    
    static void hi3110_hw_rx(struct spi_device *spi)
    {
    	struct hi3110_priv *priv = spi_get_drvdata(spi);
    	struct sk_buff *skb;
    	struct can_frame *frame;
    	u8 buf[HI3110_RX_BUF_LEN - 1];
    
    	skb = alloc_can_skb(priv->net, &frame);
    	if (!skb) {
    		priv->net->stats.rx_dropped++;
    		return;
    	}
    
    	hi3110_hw_rx_frame(spi, buf);
    	if (buf[HI3110_FIFO_WOTIME_TAG_OFF] & HI3110_FIFO_WOTIME_TAG_IDE) {
    		/* IDE is recessive (1), indicating extended 29-bit frame */
    		frame->can_id = CAN_EFF_FLAG;
    		frame->can_id |=
    			(buf[HI3110_FIFO_WOTIME_ID_OFF] << 21) |
    			(((buf[HI3110_FIFO_WOTIME_ID_OFF + 1] & 0xE0) >> 5) << 18) |
    			((buf[HI3110_FIFO_WOTIME_ID_OFF + 1] & 0x07) << 15) |
    			(buf[HI3110_FIFO_WOTIME_ID_OFF + 2] << 7) |
    			(buf[HI3110_FIFO_WOTIME_ID_OFF + 3] >> 1);
    	} else {
    		/* IDE is dominant (0), frame indicating standard 11-bit */
    		frame->can_id =
    			(buf[HI3110_FIFO_WOTIME_ID_OFF] << 3) |
    			((buf[HI3110_FIFO_WOTIME_ID_OFF + 1] & 0xE0) >> 5);
    	}
    
    	/* Data length */
    	frame->can_dlc = get_can_dlc(buf[HI3110_FIFO_WOTIME_DLC_OFF] & 0x0F);
    
    	if (buf[HI3110_FIFO_WOTIME_ID_OFF + 3] & HI3110_FIFO_WOTIME_ID_RTR)
    		frame->can_id |= CAN_RTR_FLAG;
    	else
    		memcpy(frame->data, buf + HI3110_FIFO_WOTIME_DAT_OFF,
    		       frame->can_dlc);
    
    	priv->net->stats.rx_packets++;
    	priv->net->stats.rx_bytes += frame->can_dlc;
    
    	can_led_event(priv->net, CAN_LED_EVENT_RX);
    
    	netif_rx_ni(skb);
    }
    
    static void hi3110_hw_sleep(struct spi_device *spi)
    {
    	hi3110_write(spi, HI3110_WRITE_CTRL0, HI3110_CTRL0_SLEEP_MODE);
    }
    
    static netdev_tx_t hi3110_hard_start_xmit(struct sk_buff *skb,
    					  struct net_device *net)
    {
    	struct hi3110_priv *priv = netdev_priv(net);
    	struct spi_device *spi = priv->spi;
    
    	if (priv->tx_skb || priv->tx_len) {
    		dev_err(&spi->dev, "hard_xmit called while tx busy\n");
    		return NETDEV_TX_BUSY;
    	}
    
    	if (can_dropped_invalid_skb(net, skb))
    		return NETDEV_TX_OK;
    
    	netif_stop_queue(net);
    	priv->tx_skb = skb;
    	queue_work(priv->wq, &priv->tx_work);
    
    	return NETDEV_TX_OK;
    }
    
    static int hi3110_do_set_mode(struct net_device *net, enum can_mode mode)
    {
    	struct hi3110_priv *priv = netdev_priv(net);
    
    	switch (mode) {
    	case CAN_MODE_START:
    		hi3110_clean(net);
    		/* We have to delay work since SPI I/O may sleep */
    		priv->can.state = CAN_STATE_ERROR_ACTIVE;
    		priv->restart_tx = 1;
    		if (priv->can.restart_ms == 0)
    			priv->after_suspend = HI3110_AFTER_SUSPEND_RESTART;
    		queue_work(priv->wq, &priv->restart_work);
    		break;
    	default:
    		return -EOPNOTSUPP;
    	}
    
    	return 0;
    }
    
    static int hi3110_get_berr_counter(const struct net_device *net,
    				   struct can_berr_counter *bec)
    {
    	struct hi3110_priv *priv = netdev_priv(net);
    	struct spi_device *spi = priv->spi;
    
    	mutex_lock(&priv->hi3110_lock);
    	bec->txerr = hi3110_read(spi, HI3110_READ_TEC);
    	bec->rxerr = hi3110_read(spi, HI3110_READ_REC);
    	mutex_unlock(&priv->hi3110_lock);
    
    	return 0;
    }
    
    static int hi3110_set_normal_mode(struct spi_device *spi)
    {
    	struct hi3110_priv *priv = spi_get_drvdata(spi);
    	u8 reg = 0;
    
    	hi3110_write(spi, HI3110_WRITE_INTE, HI3110_INT_BUSERR |
    		     HI3110_INT_RXFIFO | HI3110_INT_TXCPLT);
    
    	/* Enable TX */
    	hi3110_write(spi, HI3110_WRITE_CTRL1, HI3110_CTRL1_TXEN);
    
    	if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
    		reg = HI3110_CTRL0_LOOPBACK_MODE;
    	else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
    		reg = HI3110_CTRL0_MONITOR_MODE;
    	else
    		reg = HI3110_CTRL0_NORMAL_MODE;
    
    	hi3110_write(spi, HI3110_WRITE_CTRL0, reg);
    
    	/* Wait for the device to enter the mode */
    	mdelay(HI3110_OST_DELAY_MS);
    	reg = hi3110_read(spi, HI3110_READ_CTRL0);
    	if ((reg & HI3110_CTRL0_MODE_MASK) != reg)
    		return -EBUSY;
    
    	priv->can.state = CAN_STATE_ERROR_ACTIVE;
    	return 0;
    }
    
    static int hi3110_do_set_bittiming(struct net_device *net)
    {
    	struct hi3110_priv *priv = netdev_priv(net);
    	struct can_bittiming *bt = &priv->can.bittiming;
    	struct spi_device *spi = priv->spi;
    
    	hi3110_write(spi, HI3110_WRITE_BTR0,
    		     ((bt->sjw - 1) << HI3110_BTR0_SJW_SHIFT) |
    		     ((bt->brp - 1) << HI3110_BTR0_BRP_SHIFT));
    
    	hi3110_write(spi, HI3110_WRITE_BTR1,
    		     (priv->can.ctrlmode &
    		      CAN_CTRLMODE_3_SAMPLES ?
    		      HI3110_BTR1_SAMP_3PERBIT : HI3110_BTR1_SAMP_1PERBIT) |
    		     ((bt->phase_seg1 + bt->prop_seg - 1)
    		      << HI3110_BTR1_TSEG1_SHIFT) |
    		     ((bt->phase_seg2 - 1) << HI3110_BTR1_TSEG2_SHIFT));
    
    	dev_dbg(&spi->dev, "BT: 0x%02x 0x%02x\n",
    		hi3110_read(spi, HI3110_READ_BTR0),
    		hi3110_read(spi, HI3110_READ_BTR1));
    
    	return 0;
    }
    
    static int hi3110_setup(struct net_device *net)
    {
    	hi3110_do_set_bittiming(net);
    	return 0;
    }
    
    static int hi3110_hw_reset(struct spi_device *spi)
    {
    	u8 reg;
    	int ret;
    
    	/* Wait for oscillator startup timer after power up */
    	mdelay(HI3110_OST_DELAY_MS);
    
    	ret = hi3110_cmd(spi, HI3110_MASTER_RESET);
    	if (ret)
    		return ret;
    
    	/* Wait for oscillator startup timer after reset */
    	mdelay(HI3110_OST_DELAY_MS);
    
    	reg = hi3110_read(spi, HI3110_READ_CTRL0);
    	if ((reg & HI3110_CTRL0_MODE_MASK) != HI3110_CTRL0_INIT_MODE)
    		return -ENODEV;
    
    	/* As per the datasheet it appears the error flags are
    	 * not cleared on reset. Explicitly clear them by performing a read
    	 */
    	hi3110_read(spi, HI3110_READ_ERR);
    
    	return 0;
    }
    
    static int hi3110_hw_probe(struct spi_device *spi)
    {
    	u8 statf;
    
    	hi3110_hw_reset(spi);
    
    	/* Confirm correct operation by checking against reset values
    	 * in datasheet
    	 */
    	statf = hi3110_read(spi, HI3110_READ_STATF);
    
    	dev_dbg(&spi->dev, "statf: %02X\n", statf);
    
    	if (statf != 0x82)
    		return -ENODEV;
    
    	return 0;
    }
    
    static int hi3110_power_enable(struct regulator *reg, int enable)
    {
    	if (IS_ERR_OR_NULL(reg))
    		return 0;
    
    	if (enable)
    		return regulator_enable(reg);
    	else
    		return regulator_disable(reg);
    }
    
    static int hi3110_stop(struct net_device *net)
    {
    	struct hi3110_priv *priv = netdev_priv(net);
    	struct spi_device *spi = priv->spi;
    
    	close_candev(net);
    
    	priv->force_quit = 1;
    	free_irq(spi->irq, priv);
    	destroy_workqueue(priv->wq);
    	priv->wq = NULL;
    
    	mutex_lock(&priv->hi3110_lock);
    
    	/* Disable transmit, interrupts and clear flags */
    	hi3110_write(spi, HI3110_WRITE_CTRL1, 0x0);
    	hi3110_write(spi, HI3110_WRITE_INTE, 0x0);
    	hi3110_read(spi, HI3110_READ_INTF);
    
    	hi3110_clean(net);
    
    	hi3110_hw_sleep(spi);
    
    	hi3110_power_enable(priv->transceiver, 0);
    
    	priv->can.state = CAN_STATE_STOPPED;
    
    	mutex_unlock(&priv->hi3110_lock);
    
    	can_led_event(net, CAN_LED_EVENT_STOP);
    
    	return 0;
    }
    
    static void hi3110_tx_work_handler(struct work_struct *ws)
    {
    	struct hi3110_priv *priv = container_of(ws, struct hi3110_priv,
    						tx_work);
    	struct spi_device *spi = priv->spi;
    	struct net_device *net = priv->net;
    	struct can_frame *frame;
    
    	mutex_lock(&priv->hi3110_lock);
    	if (priv->tx_skb) {
    		if (priv->can.state == CAN_STATE_BUS_OFF) {
    			hi3110_clean(net);
    		} else {
    			frame = (struct can_frame *)priv->tx_skb->data;
    			hi3110_hw_tx(spi, frame);
    			priv->tx_len = 1 + frame->can_dlc;
    			can_put_echo_skb(priv->tx_skb, net, 0);
    			priv->tx_skb = NULL;
    		}
    	}
    	mutex_unlock(&priv->hi3110_lock);
    }
    
    static void hi3110_restart_work_handler(struct work_struct *ws)
    {
    	struct hi3110_priv *priv = container_of(ws, struct hi3110_priv,
    						restart_work);
    	struct spi_device *spi = priv->spi;
    	struct net_device *net = priv->net;
    
    	mutex_lock(&priv->hi3110_lock);
    	if (priv->after_suspend) {
    		hi3110_hw_reset(spi);
    		hi3110_setup(net);
    		if (priv->after_suspend & HI3110_AFTER_SUSPEND_RESTART) {
    			hi3110_set_normal_mode(spi);
    		} else if (priv->after_suspend & HI3110_AFTER_SUSPEND_UP) {
    			netif_device_attach(net);
    			hi3110_clean(net);
    			hi3110_set_normal_mode(spi);
    			netif_wake_queue(net);
    		} else {
    			hi3110_hw_sleep(spi);
    		}
    		priv->after_suspend = 0;
    		priv->force_quit = 0;
    	}
    
    	if (priv->restart_tx) {
    		priv->restart_tx = 0;
    		hi3110_hw_reset(spi);
    		hi3110_setup(net);
    		hi3110_clean(net);
    		hi3110_set_normal_mode(spi);
    		netif_wake_queue(net);
    	}
    	mutex_unlock(&priv->hi3110_lock);
    }
    
    static irqreturn_t hi3110_can_ist(int irq, void *dev_id)
    {
    	struct hi3110_priv *priv = dev_id;
    	struct spi_device *spi = priv->spi;
    	struct net_device *net = priv->net;
    
    	mutex_lock(&priv->hi3110_lock);
    
    	while (!priv->force_quit) {
    		enum can_state new_state;
    		u8 intf, eflag, statf;
    
    		while (!(HI3110_STAT_RXFMTY &
    			 (statf = hi3110_read(spi, HI3110_READ_STATF)))) {
    			hi3110_hw_rx(spi);
    		}
    
    		intf = hi3110_read(spi, HI3110_READ_INTF);
    		eflag = hi3110_read(spi, HI3110_READ_ERR);
    		/* Update can state */
    		if (eflag & HI3110_ERR_BUSOFF)
    			new_state = CAN_STATE_BUS_OFF;
    		else if (eflag & HI3110_ERR_PASSIVE_MASK)
    			new_state = CAN_STATE_ERROR_PASSIVE;
    		else if (statf & HI3110_STAT_ERRW)
    			new_state = CAN_STATE_ERROR_WARNING;
    		else
    			new_state = CAN_STATE_ERROR_ACTIVE;
    
    		if (new_state != priv->can.state) {
    			struct can_frame *cf;
    			struct sk_buff *skb;
    			enum can_state rx_state, tx_state;
    			u8 rxerr, txerr;
    
    			skb = alloc_can_err_skb(net, &cf);
    			if (!skb)
    				break;
    
    			txerr = hi3110_read(spi, HI3110_READ_TEC);
    			rxerr = hi3110_read(spi, HI3110_READ_REC);
    			cf->data[6] = txerr;
    			cf->data[7] = rxerr;
    			tx_state = txerr >= rxerr ? new_state : 0;
    			rx_state = txerr <= rxerr ? new_state : 0;
    			can_change_state(net, cf, tx_state, rx_state);
    			netif_rx_ni(skb);
    
    			if (new_state == CAN_STATE_BUS_OFF) {
    				can_bus_off(net);
    				if (priv->can.restart_ms == 0) {
    					priv->force_quit = 1;
    					hi3110_hw_sleep(spi);
    					break;
    				}
    			}
    		}
    
    		/* Update bus errors */
    		if ((intf & HI3110_INT_BUSERR) &&
    		    (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)) {
    			struct can_frame *cf;
    			struct sk_buff *skb;
    
    			/* Check for protocol errors */
    			if (eflag & HI3110_ERR_PROTOCOL_MASK) {
    				skb = alloc_can_err_skb(net, &cf);
    				if (!skb)
    					break;
    
    				cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
    				priv->can.can_stats.bus_error++;
    				priv->net->stats.rx_errors++;
    				if (eflag & HI3110_ERR_BITERR)
    					cf->data[2] |= CAN_ERR_PROT_BIT;
    				else if (eflag & HI3110_ERR_FRMERR)
    					cf->data[2] |= CAN_ERR_PROT_FORM;
    				else if (eflag & HI3110_ERR_STUFERR)
    					cf->data[2] |= CAN_ERR_PROT_STUFF;
    				else if (eflag & HI3110_ERR_CRCERR)
    					cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
    				else if (eflag & HI3110_ERR_ACKERR)
    					cf->data[3] |= CAN_ERR_PROT_LOC_ACK;
    
    				cf->data[6] = hi3110_read(spi, HI3110_READ_TEC);
    				cf->data[7] = hi3110_read(spi, HI3110_READ_REC);
    				netdev_dbg(priv->net, "Bus Error\n");
    				netif_rx_ni(skb);
    			}
    		}
    
    		if (priv->tx_len && statf & HI3110_STAT_TXMTY) {
    			net->stats.tx_packets++;
    			net->stats.tx_bytes += priv->tx_len - 1;
    			can_led_event(net, CAN_LED_EVENT_TX);
    			if (priv->tx_len) {
    				can_get_echo_skb(net, 0);
    				priv->tx_len = 0;
    			}
    			netif_wake_queue(net);
    		}
    
    		if (intf == 0)
    			break;
    	}
    	mutex_unlock(&priv->hi3110_lock);
    	return IRQ_HANDLED;
    }
    
    static int hi3110_open(struct net_device *net)
    {
    	struct hi3110_priv *priv = netdev_priv(net);
    	struct spi_device *spi = priv->spi;
    	unsigned long flags = IRQF_ONESHOT | IRQF_TRIGGER_HIGH;
    	int ret;
    
    	ret = open_candev(net);
    	if (ret)
    		return ret;
    
    	mutex_lock(&priv->hi3110_lock);
    	hi3110_power_enable(priv->transceiver, 1);
    
    	priv->force_quit = 0;
    	priv->tx_skb = NULL;
    	priv->tx_len = 0;
    
    	ret = request_threaded_irq(spi->irq, NULL, hi3110_can_ist,
    				   flags, DEVICE_NAME, priv);
    	if (ret) {
    		dev_err(&spi->dev, "failed to acquire irq %d\n", spi->irq);
    		goto out_close;
    	}
    
    	priv->wq = alloc_workqueue("hi3110_wq", WQ_FREEZABLE | WQ_MEM_RECLAIM,
    				   0);
    	if (!priv->wq) {
    		ret = -ENOMEM;
    		goto out_free_irq;
    	}
    	INIT_WORK(&priv->tx_work, hi3110_tx_work_handler);
    	INIT_WORK(&priv->restart_work, hi3110_restart_work_handler);
    
    	ret = hi3110_hw_reset(spi);
    	if (ret)
    		goto out_free_wq;
    
    	ret = hi3110_setup(net);
    	if (ret)
    		goto out_free_wq;
    
    	ret = hi3110_set_normal_mode(spi);
    	if (ret)
    		goto out_free_wq;
    
    	can_led_event(net, CAN_LED_EVENT_OPEN);
    	netif_wake_queue(net);
    	mutex_unlock(&priv->hi3110_lock);
    
    	return 0;
    
     out_free_wq:
    	destroy_workqueue(priv->wq);
     out_free_irq:
    	free_irq(spi->irq, priv);
    	hi3110_hw_sleep(spi);
     out_close:
    	hi3110_power_enable(priv->transceiver, 0);
    	close_candev(net);
    	mutex_unlock(&priv->hi3110_lock);
    	return ret;
    }
    
    static const struct net_device_ops hi3110_netdev_ops = {
    	.ndo_open = hi3110_open,
    	.ndo_stop = hi3110_stop,
    	.ndo_start_xmit = hi3110_hard_start_xmit,
    };
    
    static const struct of_device_id hi3110_of_match[] = {
    	{
    		.compatible	= "holt,hi3110",
    		.data		= (void *)CAN_HI3110_HI3110,
    	},
    	{ }
    };
    MODULE_DEVICE_TABLE(of, hi3110_of_match);
    
    static const struct spi_device_id hi3110_id_table[] = {
    	{
    		.name		= "hi3110",
    		.driver_data	= (kernel_ulong_t)CAN_HI3110_HI3110,
    	},
    	{ }
    };
    MODULE_DEVICE_TABLE(spi, hi3110_id_table);
    
    static int hi3110_can_probe(struct spi_device *spi)
    {
    	const struct of_device_id *of_id = of_match_device(hi3110_of_match,
    							   &spi->dev);
    	struct net_device *net;
    	struct hi3110_priv *priv;
    	struct clk *clk;
    	int freq, ret;
    
    	clk = devm_clk_get(&spi->dev, NULL);
    	if (IS_ERR(clk)) {
    		dev_err(&spi->dev, "no CAN clock source defined\n");
    		return PTR_ERR(clk);
    	}
    	freq = clk_get_rate(clk);
    
    	/* Sanity check */
    	if (freq > 40000000)
    		return -ERANGE;
    
    	/* Allocate can/net device */
    	net = alloc_candev(sizeof(struct hi3110_priv), HI3110_TX_ECHO_SKB_MAX);
    	if (!net)
    		return -ENOMEM;
    
    	if (!IS_ERR(clk)) {
    		ret = clk_prepare_enable(clk);
    		if (ret)
    			goto out_free;
    	}
    
    	net->netdev_ops = &hi3110_netdev_ops;
    	net->flags |= IFF_ECHO;
    
    	priv = netdev_priv(net);
    	priv->can.bittiming_const = &hi3110_bittiming_const;
    	priv->can.do_set_mode = hi3110_do_set_mode;
    	priv->can.do_get_berr_counter = hi3110_get_berr_counter;
    	priv->can.clock.freq = freq / 2;
    	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
    		CAN_CTRLMODE_LOOPBACK |
    		CAN_CTRLMODE_LISTENONLY |
    		CAN_CTRLMODE_BERR_REPORTING;
    
    	if (of_id)
    		priv->model = (enum hi3110_model)of_id->data;
    	else
    		priv->model = spi_get_device_id(spi)->driver_data;
    	priv->net = net;
    	priv->clk = clk;
    
    	spi_set_drvdata(spi, priv);
    
    	/* Configure the SPI bus */
    	spi->bits_per_word = 8;
    	ret = spi_setup(spi);
    	if (ret)
    		goto out_clk;
    
    	priv->power = devm_regulator_get_optional(&spi->dev, "vdd");
    	priv->transceiver = devm_regulator_get_optional(&spi->dev, "xceiver");
    	if ((PTR_ERR(priv->power) == -EPROBE_DEFER) ||
    	    (PTR_ERR(priv->transceiver) == -EPROBE_DEFER)) {
    		ret = -EPROBE_DEFER;
    		goto out_clk;
    	}
    
    	ret = hi3110_power_enable(priv->power, 1);
    	if (ret)
    		goto out_clk;
    
    	priv->spi = spi;
    	mutex_init(&priv->hi3110_lock);
    
    	/* If requested, allocate DMA buffers */
    	if (hi3110_enable_dma) {
    		spi->dev.coherent_dma_mask = ~0;
    
    		/* Minimum coherent DMA allocation is PAGE_SIZE, so allocate
    		 * that much and share it between Tx and Rx DMA buffers.
    		 */
    		priv->spi_tx_buf = dmam_alloc_coherent(&spi->dev,
    						       PAGE_SIZE,
    						       &priv->spi_tx_dma,
    						       GFP_DMA);
    
    		if (priv->spi_tx_buf) {
    			priv->spi_rx_buf = (priv->spi_tx_buf + (PAGE_SIZE / 2));
    			priv->spi_rx_dma = (dma_addr_t)(priv->spi_tx_dma +
    							(PAGE_SIZE / 2));
    		} else {
    			/* Fall back to non-DMA */
    			hi3110_enable_dma = 0;
    		}
    	}
    
    	/* Allocate non-DMA buffers */
    	if (!hi3110_enable_dma) {
    		priv->spi_tx_buf = devm_kzalloc(&spi->dev, HI3110_RX_BUF_LEN,
    						GFP_KERNEL);
    		if (!priv->spi_tx_buf) {
    			ret = -ENOMEM;
    			goto error_probe;
    		}
    		priv->spi_rx_buf = devm_kzalloc(&spi->dev, HI3110_RX_BUF_LEN,
    						GFP_KERNEL);
    
    		if (!priv->spi_rx_buf) {
    			ret = -ENOMEM;
    			goto error_probe;
    		}
    	}
    
    	SET_NETDEV_DEV(net, &spi->dev);
    
    	ret = hi3110_hw_probe(spi);
    	if (ret) {
    		if (ret == -ENODEV)
    			dev_err(&spi->dev, "Cannot initialize %x. Wrong wiring?\n",
    				priv->model);
    		goto error_probe;
    	}
    	hi3110_hw_sleep(spi);
    
    	ret = register_candev(net);
    	if (ret)
    		goto error_probe;
    
    	devm_can_led_init(net);
    	netdev_info(net, "%x successfully initialized.\n", priv->model);
    
    	return 0;
    
     error_probe:
    	hi3110_power_enable(priv->power, 0);
    
     out_clk:
    	if (!IS_ERR(clk))
    		clk_disable_unprepare(clk);
    
     out_free:
    	free_candev(net);
    
    	dev_err(&spi->dev, "Probe failed, err=%d\n", -ret);
    	return ret;
    }
    
    static int hi3110_can_remove(struct spi_device *spi)
    {
    	struct hi3110_priv *priv = spi_get_drvdata(spi);
    	struct net_device *net = priv->net;
    
    	unregister_candev(net);
    
    	hi3110_power_enable(priv->power, 0);
    
    	if (!IS_ERR(priv->clk))
    		clk_disable_unprepare(priv->clk);
    
    	free_candev(net);
    
    	return 0;
    }
    
    static int __maybe_unused hi3110_can_suspend(struct device *dev)
    {
    	struct spi_device *spi = to_spi_device(dev);
    	struct hi3110_priv *priv = spi_get_drvdata(spi);
    	struct net_device *net = priv->net;
    
    	priv->force_quit = 1;
    	disable_irq(spi->irq);
    
    	/* Note: at this point neither IST nor workqueues are running.
    	 * open/stop cannot be called anyway so locking is not needed
    	 */
    	if (netif_running(net)) {
    		netif_device_detach(net);
    
    		hi3110_hw_sleep(spi);
    		hi3110_power_enable(priv->transceiver, 0);
    		priv->after_suspend = HI3110_AFTER_SUSPEND_UP;
    	} else {
    		priv->after_suspend = HI3110_AFTER_SUSPEND_DOWN;
    	}
    
    	if (!IS_ERR_OR_NULL(priv->power)) {
    		regulator_disable(priv->power);
    		priv->after_suspend |= HI3110_AFTER_SUSPEND_POWER;
    	}
    
    	return 0;
    }
    
    static int __maybe_unused hi3110_can_resume(struct device *dev)
    {
    	struct spi_device *spi = to_spi_device(dev);
    	struct hi3110_priv *priv = spi_get_drvdata(spi);
    
    	if (priv->after_suspend & HI3110_AFTER_SUSPEND_POWER)
    		hi3110_power_enable(priv->power, 1);
    
    	if (priv->after_suspend & HI3110_AFTER_SUSPEND_UP) {
    		hi3110_power_enable(priv->transceiver, 1);
    		queue_work(priv->wq, &priv->restart_work);
    	} else {
    		priv->after_suspend = 0;
    	}
    
    	priv->force_quit = 0;
    	enable_irq(spi->irq);
    	return 0;
    }
    
    static SIMPLE_DEV_PM_OPS(hi3110_can_pm_ops, hi3110_can_suspend, hi3110_can_resume);
    
    static struct spi_driver hi3110_can_driver = {
    	.driver = {
    		.name = DEVICE_NAME,
    		.of_match_table = hi3110_of_match,
    		.pm = &hi3110_can_pm_ops,
    	},
    	.id_table = hi3110_id_table,
    	.probe = hi3110_can_probe,
    	.remove = hi3110_can_remove,
    };
    
    module_spi_driver(hi3110_can_driver);
    
    MODULE_AUTHOR("Akshay Bhat <akshay.bhat@timesys.com>");
    MODULE_AUTHOR("Casey Fitzpatrick <casey.fitzpatrick@timesys.com>");
    MODULE_DESCRIPTION("Holt HI-3110 CAN driver");
    MODULE_LICENSE("GPL v2");
    

    /*
     * CAN bus driver for Microchip 251x/25625 CAN Controller with SPI Interface
     *
     * MCP2510 support and bug fixes by Christian Pellegrin
     * <chripell@evolware.org>
     *
     * Copyright 2009 Christian Pellegrin EVOL S.r.l.
     *
     * Copyright 2007 Raymarine UK, Ltd. All Rights Reserved.
     * Written under contract by:
     *   Chris Elston, Katalix Systems, Ltd.
     *
     * Based on Microchip MCP251x CAN controller driver written by
     * David Vrabel, Copyright 2006 Arcom Control Systems Ltd.
     *
     * Based on CAN bus driver for the CCAN controller written by
     * - Sascha Hauer, Marc Kleine-Budde, Pengutronix
     * - Simon Kallweit, intefo AG
     * Copyright 2007
     *
     * This program is free software; you can redistribute it and/or modify
     * it under the terms of the version 2 of the GNU General Public License
     * as published by the Free Software Foundation
     *
     * This program is distributed in the hope that it will be useful,
     * but WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
     * GNU General Public License for more details.
     *
     * You should have received a copy of the GNU General Public License
     * along with this program; if not, see <http://www.gnu.org/licenses/>.
     *
     *
     *
     * Your platform definition file should specify something like:
     *
     * static struct mcp251x_platform_data mcp251x_info = {
     *         .oscillator_frequency = 8000000,
     * };
     *
     * static struct spi_board_info spi_board_info[] = {
     *         {
     *                 .modalias = "mcp2510",
     *			// "mcp2515" or "mcp25625" depending on your controller
     *                 .platform_data = &mcp251x_info,
     *                 .irq = IRQ_EINT13,
     *                 .max_speed_hz = 2*1000*1000,
     *                 .chip_select = 2,
     *         },
     * };
     *
     * Please see mcp251x.h for a description of the fields in
     * struct mcp251x_platform_data.
     *
     */
    
    #include <linux/can/core.h>
    #include <linux/can/dev.h>
    #include <linux/can/led.h>
    #include <linux/can/platform/mcp251x.h>
    #include <linux/clk.h>
    #include <linux/completion.h>
    #include <linux/delay.h>
    #include <linux/device.h>
    #include <linux/dma-mapping.h>
    #include <linux/freezer.h>
    #include <linux/interrupt.h>
    #include <linux/io.h>
    #include <linux/kernel.h>
    #include <linux/module.h>
    #include <linux/netdevice.h>
    #include <linux/of.h>
    #include <linux/of_device.h>
    #include <linux/platform_device.h>
    #include <linux/slab.h>
    #include <linux/spi/spi.h>
    #include <linux/uaccess.h>
    #include <linux/regulator/consumer.h>
    
    /* SPI interface instruction set */
    #define INSTRUCTION_WRITE	0x02
    #define INSTRUCTION_READ	0x03
    #define INSTRUCTION_BIT_MODIFY	0x05
    #define INSTRUCTION_LOAD_TXB(n)	(0x40 + 2 * (n))
    #define INSTRUCTION_READ_RXB(n)	(((n) == 0) ? 0x90 : 0x94)
    #define INSTRUCTION_RESET	0xC0
    #define RTS_TXB0		0x01
    #define RTS_TXB1		0x02
    #define RTS_TXB2		0x04
    #define INSTRUCTION_RTS(n)	(0x80 | ((n) & 0x07))
    
    
    /* MPC251x registers */
    #define CANSTAT	      0x0e
    #define CANCTRL	      0x0f
    #  define CANCTRL_REQOP_MASK	    0xe0
    #  define CANCTRL_REQOP_CONF	    0x80
    #  define CANCTRL_REQOP_LISTEN_ONLY 0x60
    #  define CANCTRL_REQOP_LOOPBACK    0x40
    #  define CANCTRL_REQOP_SLEEP	    0x20
    #  define CANCTRL_REQOP_NORMAL	    0x00
    #  define CANCTRL_OSM		    0x08
    #  define CANCTRL_ABAT		    0x10
    #define TEC	      0x1c
    #define REC	      0x1d
    #define CNF1	      0x2a
    #  define CNF1_SJW_SHIFT   6
    #define CNF2	      0x29
    #  define CNF2_BTLMODE	   0x80
    #  define CNF2_SAM         0x40
    #  define CNF2_PS1_SHIFT   3
    #define CNF3	      0x28
    #  define CNF3_SOF	   0x08
    #  define CNF3_WAKFIL	   0x04
    #  define CNF3_PHSEG2_MASK 0x07
    #define CANINTE	      0x2b
    #  define CANINTE_MERRE 0x80
    #  define CANINTE_WAKIE 0x40
    #  define CANINTE_ERRIE 0x20
    #  define CANINTE_TX2IE 0x10
    #  define CANINTE_TX1IE 0x08
    #  define CANINTE_TX0IE 0x04
    #  define CANINTE_RX1IE 0x02
    #  define CANINTE_RX0IE 0x01
    #define CANINTF	      0x2c
    #  define CANINTF_MERRF 0x80
    #  define CANINTF_WAKIF 0x40
    #  define CANINTF_ERRIF 0x20
    #  define CANINTF_TX2IF 0x10
    #  define CANINTF_TX1IF 0x08
    #  define CANINTF_TX0IF 0x04
    #  define CANINTF_RX1IF 0x02
    #  define CANINTF_RX0IF 0x01
    #  define CANINTF_RX (CANINTF_RX0IF | CANINTF_RX1IF)
    #  define CANINTF_TX (CANINTF_TX2IF | CANINTF_TX1IF | CANINTF_TX0IF)
    #  define CANINTF_ERR (CANINTF_ERRIF)
    #define EFLG	      0x2d
    #  define EFLG_EWARN	0x01
    #  define EFLG_RXWAR	0x02
    #  define EFLG_TXWAR	0x04
    #  define EFLG_RXEP	0x08
    #  define EFLG_TXEP	0x10
    #  define EFLG_TXBO	0x20
    #  define EFLG_RX0OVR	0x40
    #  define EFLG_RX1OVR	0x80
    #define TXBCTRL(n)  (((n) * 0x10) + 0x30 + TXBCTRL_OFF)
    #  define TXBCTRL_ABTF	0x40
    #  define TXBCTRL_MLOA	0x20
    #  define TXBCTRL_TXERR 0x10
    #  define TXBCTRL_TXREQ 0x08
    #define TXBSIDH(n)  (((n) * 0x10) + 0x30 + TXBSIDH_OFF)
    #  define SIDH_SHIFT    3
    #define TXBSIDL(n)  (((n) * 0x10) + 0x30 + TXBSIDL_OFF)
    #  define SIDL_SID_MASK    7
    #  define SIDL_SID_SHIFT   5
    #  define SIDL_EXIDE_SHIFT 3
    #  define SIDL_EID_SHIFT   16
    #  define SIDL_EID_MASK    3
    #define TXBEID8(n)  (((n) * 0x10) + 0x30 + TXBEID8_OFF)
    #define TXBEID0(n)  (((n) * 0x10) + 0x30 + TXBEID0_OFF)
    #define TXBDLC(n)   (((n) * 0x10) + 0x30 + TXBDLC_OFF)
    #  define DLC_RTR_SHIFT    6
    #define TXBCTRL_OFF 0
    #define TXBSIDH_OFF 1
    #define TXBSIDL_OFF 2
    #define TXBEID8_OFF 3
    #define TXBEID0_OFF 4
    #define TXBDLC_OFF  5
    #define TXBDAT_OFF  6
    #define RXBCTRL(n)  (((n) * 0x10) + 0x60 + RXBCTRL_OFF)
    #  define RXBCTRL_BUKT	0x04
    #  define RXBCTRL_RXM0	0x20
    #  define RXBCTRL_RXM1	0x40
    #define RXBSIDH(n)  (((n) * 0x10) + 0x60 + RXBSIDH_OFF)
    #  define RXBSIDH_SHIFT 3
    #define RXBSIDL(n)  (((n) * 0x10) + 0x60 + RXBSIDL_OFF)
    #  define RXBSIDL_IDE   0x08
    #  define RXBSIDL_SRR   0x10
    #  define RXBSIDL_EID   3
    #  define RXBSIDL_SHIFT 5
    #define RXBEID8(n)  (((n) * 0x10) + 0x60 + RXBEID8_OFF)
    #define RXBEID0(n)  (((n) * 0x10) + 0x60 + RXBEID0_OFF)
    #define RXBDLC(n)   (((n) * 0x10) + 0x60 + RXBDLC_OFF)
    #  define RXBDLC_LEN_MASK  0x0f
    #  define RXBDLC_RTR       0x40
    #define RXBCTRL_OFF 0
    #define RXBSIDH_OFF 1
    #define RXBSIDL_OFF 2
    #define RXBEID8_OFF 3
    #define RXBEID0_OFF 4
    #define RXBDLC_OFF  5
    #define RXBDAT_OFF  6
    #define RXFSID(n) ((n < 3) ? 0 : 4)
    #define RXFSIDH(n) ((n) * 4 + RXFSID(n))
    #define RXFSIDL(n) ((n) * 4 + 1 + RXFSID(n))
    #define RXFEID8(n) ((n) * 4 + 2 + RXFSID(n))
    #define RXFEID0(n) ((n) * 4 + 3 + RXFSID(n))
    #define RXMSIDH(n) ((n) * 4 + 0x20)
    #define RXMSIDL(n) ((n) * 4 + 0x21)
    #define RXMEID8(n) ((n) * 4 + 0x22)
    #define RXMEID0(n) ((n) * 4 + 0x23)
    
    #define GET_BYTE(val, byte)			\
    	(((val) >> ((byte) * 8)) & 0xff)
    #define SET_BYTE(val, byte)			\
    	(((val) & 0xff) << ((byte) * 8))
    
    /*
     * Buffer size required for the largest SPI transfer (i.e., reading a
     * frame)
     */
    #define CAN_FRAME_MAX_DATA_LEN	8
    #define SPI_TRANSFER_BUF_LEN	(6 + CAN_FRAME_MAX_DATA_LEN)
    #define CAN_FRAME_MAX_BITS	128
    
    #define TX_ECHO_SKB_MAX	1
    
    #define MCP251X_OST_DELAY_MS	(5)
    
    #define DEVICE_NAME "mcp251x"
    
    static int mcp251x_enable_dma; /* Enable SPI DMA. Default: 0 (Off) */
    module_param(mcp251x_enable_dma, int, 0444);
    MODULE_PARM_DESC(mcp251x_enable_dma, "Enable SPI DMA. Default: 0 (Off)");
    
    static const struct can_bittiming_const mcp251x_bittiming_const = {
    	.name = DEVICE_NAME,
    	.tseg1_min = 3,
    	.tseg1_max = 16,
    	.tseg2_min = 2,
    	.tseg2_max = 8,
    	.sjw_max = 4,
    	.brp_min = 1,
    	.brp_max = 64,
    	.brp_inc = 1,
    };
    
    enum mcp251x_model {
    	CAN_MCP251X_MCP2510	= 0x2510,
    	CAN_MCP251X_MCP2515	= 0x2515,
    	CAN_MCP251X_MCP25625	= 0x25625,
    };
    
    struct mcp251x_priv {
    	struct can_priv	   can;
    	struct net_device *net;
    	struct spi_device *spi;
    	enum mcp251x_model model;
    
    	struct mutex mcp_lock; /* SPI device lock */
    
    	u8 *spi_tx_buf;
    	u8 *spi_rx_buf;
    	dma_addr_t spi_tx_dma;
    	dma_addr_t spi_rx_dma;
    
    	struct sk_buff *tx_skb;
    	int tx_len;
    
    	struct workqueue_struct *wq;
    	struct work_struct tx_work;
    	struct work_struct restart_work;
    
    	int force_quit;
    	int after_suspend;
    #define AFTER_SUSPEND_UP 1
    #define AFTER_SUSPEND_DOWN 2
    #define AFTER_SUSPEND_POWER 4
    #define AFTER_SUSPEND_RESTART 8
    	int restart_tx;
    	struct regulator *power;
    	struct regulator *transceiver;
    	struct clk *clk;
    };
    
    #define MCP251X_IS(_model) \
    static inline int mcp251x_is_##_model(struct spi_device *spi) \
    { \
    	struct mcp251x_priv *priv = spi_get_drvdata(spi); \
    	return priv->model == CAN_MCP251X_MCP##_model; \
    }
    
    MCP251X_IS(2510);
    
    static void mcp251x_clean(struct net_device *net)
    {
    	struct mcp251x_priv *priv = netdev_priv(net);
    
    	if (priv->tx_skb || priv->tx_len)
    		net->stats.tx_errors++;
    	if (priv->tx_skb)
    		dev_kfree_skb(priv->tx_skb);
    	if (priv->tx_len)
    		can_free_echo_skb(priv->net, 0);
    	priv->tx_skb = NULL;
    	priv->tx_len = 0;
    }
    
    /*
     * Note about handling of error return of mcp251x_spi_trans: accessing
     * registers via SPI is not really different conceptually than using
     * normal I/O assembler instructions, although it's much more
     * complicated from a practical POV. So it's not advisable to always
     * check the return value of this function. Imagine that every
     * read{b,l}, write{b,l} and friends would be bracketed in "if ( < 0)
     * error();", it would be a great mess (well there are some situation
     * when exception handling C++ like could be useful after all). So we
     * just check that transfers are OK at the beginning of our
     * conversation with the chip and to avoid doing really nasty things
     * (like injecting bogus packets in the network stack).
     */
    static int mcp251x_spi_trans(struct spi_device *spi, int len)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    	struct spi_transfer t = {
    		.tx_buf = priv->spi_tx_buf,
    		.rx_buf = priv->spi_rx_buf,
    		.len = len,
    		.cs_change = 0,
    	};
    	struct spi_message m;
    	int ret;
    
    	spi_message_init(&m);
    
    	if (mcp251x_enable_dma) {
    		t.tx_dma = priv->spi_tx_dma;
    		t.rx_dma = priv->spi_rx_dma;
    		m.is_dma_mapped = 1;
    	}
    
    	spi_message_add_tail(&t, &m);
    
    	ret = spi_sync(spi, &m);
    	if (ret)
    		dev_err(&spi->dev, "spi transfer failed: ret = %d\n", ret);
    	return ret;
    }
    
    static u8 mcp251x_read_reg(struct spi_device *spi, uint8_t reg)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    	u8 val = 0;
    
    	priv->spi_tx_buf[0] = INSTRUCTION_READ;
    	priv->spi_tx_buf[1] = reg;
    
    	mcp251x_spi_trans(spi, 3);
    	val = priv->spi_rx_buf[2];
    
    	return val;
    }
    
    static void mcp251x_read_2regs(struct spi_device *spi, uint8_t reg,
    		uint8_t *v1, uint8_t *v2)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    
    	priv->spi_tx_buf[0] = INSTRUCTION_READ;
    	priv->spi_tx_buf[1] = reg;
    
    	mcp251x_spi_trans(spi, 4);
    
    	*v1 = priv->spi_rx_buf[2];
    	*v2 = priv->spi_rx_buf[3];
    }
    
    static void mcp251x_write_reg(struct spi_device *spi, u8 reg, uint8_t val)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    
    	priv->spi_tx_buf[0] = INSTRUCTION_WRITE;
    	priv->spi_tx_buf[1] = reg;
    	priv->spi_tx_buf[2] = val;
    
    	mcp251x_spi_trans(spi, 3);
    }
    
    static void mcp251x_write_bits(struct spi_device *spi, u8 reg,
    			       u8 mask, uint8_t val)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    
    	priv->spi_tx_buf[0] = INSTRUCTION_BIT_MODIFY;
    	priv->spi_tx_buf[1] = reg;
    	priv->spi_tx_buf[2] = mask;
    	priv->spi_tx_buf[3] = val;
    
    	mcp251x_spi_trans(spi, 4);
    }
    
    static void mcp251x_hw_tx_frame(struct spi_device *spi, u8 *buf,
    				int len, int tx_buf_idx)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    
    	if (mcp251x_is_2510(spi)) {
    		int i;
    
    		for (i = 1; i < TXBDAT_OFF + len; i++)
    			mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx) + i,
    					  buf[i]);
    	} else {
    		memcpy(priv->spi_tx_buf, buf, TXBDAT_OFF + len);
    		mcp251x_spi_trans(spi, TXBDAT_OFF + len);
    	}
    }
    
    static void mcp251x_hw_tx(struct spi_device *spi, struct can_frame *frame,
    			  int tx_buf_idx)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    	u32 sid, eid, exide, rtr;
    	u8 buf[SPI_TRANSFER_BUF_LEN];
    
    	exide = (frame->can_id & CAN_EFF_FLAG) ? 1 : 0; /* Extended ID Enable */
    	if (exide)
    		sid = (frame->can_id & CAN_EFF_MASK) >> 18;
    	else
    		sid = frame->can_id & CAN_SFF_MASK; /* Standard ID */
    	eid = frame->can_id & CAN_EFF_MASK; /* Extended ID */
    	rtr = (frame->can_id & CAN_RTR_FLAG) ? 1 : 0; /* Remote transmission */
    
    	buf[TXBCTRL_OFF] = INSTRUCTION_LOAD_TXB(tx_buf_idx);
    	buf[TXBSIDH_OFF] = sid >> SIDH_SHIFT;
    	buf[TXBSIDL_OFF] = ((sid & SIDL_SID_MASK) << SIDL_SID_SHIFT) |
    		(exide << SIDL_EXIDE_SHIFT) |
    		((eid >> SIDL_EID_SHIFT) & SIDL_EID_MASK);
    	buf[TXBEID8_OFF] = GET_BYTE(eid, 1);
    	buf[TXBEID0_OFF] = GET_BYTE(eid, 0);
    	buf[TXBDLC_OFF] = (rtr << DLC_RTR_SHIFT) | frame->can_dlc;
    	memcpy(buf + TXBDAT_OFF, frame->data, frame->can_dlc);
    	mcp251x_hw_tx_frame(spi, buf, frame->can_dlc, tx_buf_idx);
    
    	/* use INSTRUCTION_RTS, to avoid "repeated frame problem" */
    	priv->spi_tx_buf[0] = INSTRUCTION_RTS(1 << tx_buf_idx);
    	mcp251x_spi_trans(priv->spi, 1);
    }
    
    static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf,
    				int buf_idx)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    
    	if (mcp251x_is_2510(spi)) {
    		int i, len;
    
    		for (i = 1; i < RXBDAT_OFF; i++)
    			buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);
    
    		len = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK);
    		for (; i < (RXBDAT_OFF + len); i++)
    			buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);
    	} else {
    		priv->spi_tx_buf[RXBCTRL_OFF] = INSTRUCTION_READ_RXB(buf_idx);
    		mcp251x_spi_trans(spi, SPI_TRANSFER_BUF_LEN);
    		memcpy(buf, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN);
    	}
    }
    
    static void mcp251x_hw_rx(struct spi_device *spi, int buf_idx)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    	struct sk_buff *skb;
    	struct can_frame *frame;
    	u8 buf[SPI_TRANSFER_BUF_LEN];
    
    	skb = alloc_can_skb(priv->net, &frame);
    	if (!skb) {
    		dev_err(&spi->dev, "cannot allocate RX skb\n");
    		priv->net->stats.rx_dropped++;
    		return;
    	}
    
    	mcp251x_hw_rx_frame(spi, buf, buf_idx);
    	if (buf[RXBSIDL_OFF] & RXBSIDL_IDE) {
    		/* Extended ID format */
    		frame->can_id = CAN_EFF_FLAG;
    		frame->can_id |=
    			/* Extended ID part */
    			SET_BYTE(buf[RXBSIDL_OFF] & RXBSIDL_EID, 2) |
    			SET_BYTE(buf[RXBEID8_OFF], 1) |
    			SET_BYTE(buf[RXBEID0_OFF], 0) |
    			/* Standard ID part */
    			(((buf[RXBSIDH_OFF] << RXBSIDH_SHIFT) |
    			  (buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT)) << 18);
    		/* Remote transmission request */
    		if (buf[RXBDLC_OFF] & RXBDLC_RTR)
    			frame->can_id |= CAN_RTR_FLAG;
    	} else {
    		/* Standard ID format */
    		frame->can_id =
    			(buf[RXBSIDH_OFF] << RXBSIDH_SHIFT) |
    			(buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT);
    		if (buf[RXBSIDL_OFF] & RXBSIDL_SRR)
    			frame->can_id |= CAN_RTR_FLAG;
    	}
    	/* Data length */
    	frame->can_dlc = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK);
    	memcpy(frame->data, buf + RXBDAT_OFF, frame->can_dlc);
    
    	priv->net->stats.rx_packets++;
    	priv->net->stats.rx_bytes += frame->can_dlc;
    
    	can_led_event(priv->net, CAN_LED_EVENT_RX);
    
    	netif_rx_ni(skb);
    }
    
    static void mcp251x_hw_sleep(struct spi_device *spi)
    {
    	mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_SLEEP);
    }
    
    static netdev_tx_t mcp251x_hard_start_xmit(struct sk_buff *skb,
    					   struct net_device *net)
    {
    	struct mcp251x_priv *priv = netdev_priv(net);
    	struct spi_device *spi = priv->spi;
    
    	if (priv->tx_skb || priv->tx_len) {
    		dev_warn(&spi->dev, "hard_xmit called while tx busy\n");
    		return NETDEV_TX_BUSY;
    	}
    
    	if (can_dropped_invalid_skb(net, skb))
    		return NETDEV_TX_OK;
    
    	netif_stop_queue(net);
    	priv->tx_skb = skb;
    	queue_work(priv->wq, &priv->tx_work);
    
    	return NETDEV_TX_OK;
    }
    
    static int mcp251x_do_set_mode(struct net_device *net, enum can_mode mode)
    {
    	struct mcp251x_priv *priv = netdev_priv(net);
    
    	switch (mode) {
    	case CAN_MODE_START:
    		mcp251x_clean(net);
    		/* We have to delay work since SPI I/O may sleep */
    		priv->can.state = CAN_STATE_ERROR_ACTIVE;
    		priv->restart_tx = 1;
    		if (priv->can.restart_ms == 0)
    			priv->after_suspend = AFTER_SUSPEND_RESTART;
    		queue_work(priv->wq, &priv->restart_work);
    		break;
    	default:
    		return -EOPNOTSUPP;
    	}
    
    	return 0;
    }
    
    static int mcp251x_set_normal_mode(struct spi_device *spi)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    	unsigned long timeout;
    
    	/* Enable interrupts */
    	mcp251x_write_reg(spi, CANINTE,
    			  CANINTE_ERRIE | CANINTE_TX2IE | CANINTE_TX1IE |
    			  CANINTE_TX0IE | CANINTE_RX1IE | CANINTE_RX0IE);
    
    	if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
    		/* Put device into loopback mode */
    		mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_LOOPBACK);
    	} else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
    		/* Put device into listen-only mode */
    		mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_LISTEN_ONLY);
    	} else {
    		/* Put device into normal mode */
    		mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_NORMAL);
    
    		/* Wait for the device to enter normal mode */
    		timeout = jiffies + HZ;
    		while (mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK) {
    			schedule();
    			if (time_after(jiffies, timeout)) {
    				dev_err(&spi->dev, "MCP251x didn't"
    					" enter in normal mode\n");
    				return -EBUSY;
    			}
    		}
    	}
    	priv->can.state = CAN_STATE_ERROR_ACTIVE;
    	return 0;
    }
    
    static int mcp251x_do_set_bittiming(struct net_device *net)
    {
    	struct mcp251x_priv *priv = netdev_priv(net);
    	struct can_bittiming *bt = &priv->can.bittiming;
    	struct spi_device *spi = priv->spi;
    
    	mcp251x_write_reg(spi, CNF1, ((bt->sjw - 1) << CNF1_SJW_SHIFT) |
    			  (bt->brp - 1));
    	mcp251x_write_reg(spi, CNF2, CNF2_BTLMODE |
    			  (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES ?
    			   CNF2_SAM : 0) |
    			  ((bt->phase_seg1 - 1) << CNF2_PS1_SHIFT) |
    			  (bt->prop_seg - 1));
    	mcp251x_write_bits(spi, CNF3, CNF3_PHSEG2_MASK,
    			   (bt->phase_seg2 - 1));
    	dev_dbg(&spi->dev, "CNF: 0x%02x 0x%02x 0x%02x\n",
    		mcp251x_read_reg(spi, CNF1),
    		mcp251x_read_reg(spi, CNF2),
    		mcp251x_read_reg(spi, CNF3));
    
    	return 0;
    }
    
    static int mcp251x_setup(struct net_device *net, struct spi_device *spi)
    {
    	mcp251x_do_set_bittiming(net);
    
    	mcp251x_write_reg(spi, RXBCTRL(0),
    			  RXBCTRL_BUKT | RXBCTRL_RXM0 | RXBCTRL_RXM1);
    	mcp251x_write_reg(spi, RXBCTRL(1),
    			  RXBCTRL_RXM0 | RXBCTRL_RXM1);
    	return 0;
    }
    
    static int mcp251x_hw_reset(struct spi_device *spi)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    	unsigned long timeout;
    	int ret;
    
    	/* Wait for oscillator startup timer after power up */
    	mdelay(MCP251X_OST_DELAY_MS);
    
    	priv->spi_tx_buf[0] = INSTRUCTION_RESET;
    	ret = mcp251x_spi_trans(spi, 1);
    	if (ret)
    		return ret;
    
    	/* Wait for oscillator startup timer after reset */
    	mdelay(MCP251X_OST_DELAY_MS);
    
    	/* Wait for reset to finish */
    	timeout = jiffies + HZ;
    	while ((mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK) !=
    	       CANCTRL_REQOP_CONF) {
    		usleep_range(MCP251X_OST_DELAY_MS * 1000,
    			     MCP251X_OST_DELAY_MS * 1000 * 2);
    
    		if (time_after(jiffies, timeout)) {
    			dev_err(&spi->dev,
    				"MCP251x didn't enter in conf mode after reset\n");
    			return -EBUSY;
    		}
    	}
    	return 0;
    }
    
    static int mcp251x_hw_probe(struct spi_device *spi)
    {
    	u8 ctrl;
    	int ret;
    
    	ret = mcp251x_hw_reset(spi);
    	if (ret)
    		return ret;
    
    	ctrl = mcp251x_read_reg(spi, CANCTRL);
    
    	dev_dbg(&spi->dev, "CANCTRL 0x%02x\n", ctrl);
    
    	/* Check for power up default value */
    	if ((ctrl & 0x17) != 0x07)
    		return -ENODEV;
    
    	return 0;
    }
    
    static int mcp251x_power_enable(struct regulator *reg, int enable)
    {
    	if (IS_ERR_OR_NULL(reg))
    		return 0;
    
    	if (enable)
    		return regulator_enable(reg);
    	else
    		return regulator_disable(reg);
    }
    
    static int mcp251x_stop(struct net_device *net)
    {
    	struct mcp251x_priv *priv = netdev_priv(net);
    	struct spi_device *spi = priv->spi;
    
    	close_candev(net);
    
    	priv->force_quit = 1;
    	free_irq(spi->irq, priv);
    	destroy_workqueue(priv->wq);
    	priv->wq = NULL;
    
    	mutex_lock(&priv->mcp_lock);
    
    	/* Disable and clear pending interrupts */
    	mcp251x_write_reg(spi, CANINTE, 0x00);
    	mcp251x_write_reg(spi, CANINTF, 0x00);
    
    	mcp251x_write_reg(spi, TXBCTRL(0), 0);
    	mcp251x_clean(net);
    
    	mcp251x_hw_sleep(spi);
    
    	mcp251x_power_enable(priv->transceiver, 0);
    
    	priv->can.state = CAN_STATE_STOPPED;
    
    	mutex_unlock(&priv->mcp_lock);
    
    	can_led_event(net, CAN_LED_EVENT_STOP);
    
    	return 0;
    }
    
    static void mcp251x_error_skb(struct net_device *net, int can_id, int data1)
    {
    	struct sk_buff *skb;
    	struct can_frame *frame;
    
    	skb = alloc_can_err_skb(net, &frame);
    	if (skb) {
    		frame->can_id |= can_id;
    		frame->data[1] = data1;
    		netif_rx_ni(skb);
    	} else {
    		netdev_err(net, "cannot allocate error skb\n");
    	}
    }
    
    static void mcp251x_tx_work_handler(struct work_struct *ws)
    {
    	struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv,
    						 tx_work);
    	struct spi_device *spi = priv->spi;
    	struct net_device *net = priv->net;
    	struct can_frame *frame;
    
    	mutex_lock(&priv->mcp_lock);
    	if (priv->tx_skb) {
    		if (priv->can.state == CAN_STATE_BUS_OFF) {
    			mcp251x_clean(net);
    		} else {
    			frame = (struct can_frame *)priv->tx_skb->data;
    
    			if (frame->can_dlc > CAN_FRAME_MAX_DATA_LEN)
    				frame->can_dlc = CAN_FRAME_MAX_DATA_LEN;
    			mcp251x_hw_tx(spi, frame, 0);
    			priv->tx_len = 1 + frame->can_dlc;
    			can_put_echo_skb(priv->tx_skb, net, 0);
    			priv->tx_skb = NULL;
    		}
    	}
    	mutex_unlock(&priv->mcp_lock);
    }
    
    static void mcp251x_restart_work_handler(struct work_struct *ws)
    {
    	struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv,
    						 restart_work);
    	struct spi_device *spi = priv->spi;
    	struct net_device *net = priv->net;
    
    	mutex_lock(&priv->mcp_lock);
    	if (priv->after_suspend) {
    		mcp251x_hw_reset(spi);
    		mcp251x_setup(net, spi);
    		priv->force_quit = 0;
    		if (priv->after_suspend & AFTER_SUSPEND_RESTART) {
    			mcp251x_set_normal_mode(spi);
    		} else if (priv->after_suspend & AFTER_SUSPEND_UP) {
    			netif_device_attach(net);
    			mcp251x_clean(net);
    			mcp251x_set_normal_mode(spi);
    			netif_wake_queue(net);
    		} else {
    			mcp251x_hw_sleep(spi);
    		}
    		priv->after_suspend = 0;
    	}
    
    	if (priv->restart_tx) {
    		priv->restart_tx = 0;
    		mcp251x_write_reg(spi, TXBCTRL(0), 0);
    		mcp251x_clean(net);
    		netif_wake_queue(net);
    		mcp251x_error_skb(net, CAN_ERR_RESTARTED, 0);
    	}
    	mutex_unlock(&priv->mcp_lock);
    }
    
    static irqreturn_t mcp251x_can_ist(int irq, void *dev_id)
    {
    	struct mcp251x_priv *priv = dev_id;
    	struct spi_device *spi = priv->spi;
    	struct net_device *net = priv->net;
    
    	mutex_lock(&priv->mcp_lock);
    	while (!priv->force_quit) {
    		enum can_state new_state;
    		u8 intf, eflag;
    		u8 clear_intf = 0;
    		int can_id = 0, data1 = 0;
    
    		mcp251x_read_2regs(spi, CANINTF, &intf, &eflag);
    
    		/* mask out flags we don't care about */
    		intf &= CANINTF_RX | CANINTF_TX | CANINTF_ERR;
    
    		/* receive buffer 0 */
    		if (intf & CANINTF_RX0IF) {
    			mcp251x_hw_rx(spi, 0);
    			/* Free one buffer ASAP
    			 * (The MCP2515/25625 does this automatically.)
    			 */
    			if (mcp251x_is_2510(spi))
    				mcp251x_write_bits(spi, CANINTF, CANINTF_RX0IF, 0x00);
    		}
    
    		/* receive buffer 1 */
    		if (intf & CANINTF_RX1IF) {
    			mcp251x_hw_rx(spi, 1);
    			/* The MCP2515/25625 does this automatically. */
    			if (mcp251x_is_2510(spi))
    				clear_intf |= CANINTF_RX1IF;
    		}
    
    		/* any error or tx interrupt we need to clear? */
    		if (intf & (CANINTF_ERR | CANINTF_TX))
    			clear_intf |= intf & (CANINTF_ERR | CANINTF_TX);
    		if (clear_intf)
    			mcp251x_write_bits(spi, CANINTF, clear_intf, 0x00);
    
    		if (eflag & (EFLG_RX0OVR | EFLG_RX1OVR))
    			mcp251x_write_bits(spi, EFLG, eflag, 0x00);
    
    		/* Update can state */
    		if (eflag & EFLG_TXBO) {
    			new_state = CAN_STATE_BUS_OFF;
    			can_id |= CAN_ERR_BUSOFF;
    		} else if (eflag & EFLG_TXEP) {
    			new_state = CAN_STATE_ERROR_PASSIVE;
    			can_id |= CAN_ERR_CRTL;
    			data1 |= CAN_ERR_CRTL_TX_PASSIVE;
    		} else if (eflag & EFLG_RXEP) {
    			new_state = CAN_STATE_ERROR_PASSIVE;
    			can_id |= CAN_ERR_CRTL;
    			data1 |= CAN_ERR_CRTL_RX_PASSIVE;
    		} else if (eflag & EFLG_TXWAR) {
    			new_state = CAN_STATE_ERROR_WARNING;
    			can_id |= CAN_ERR_CRTL;
    			data1 |= CAN_ERR_CRTL_TX_WARNING;
    		} else if (eflag & EFLG_RXWAR) {
    			new_state = CAN_STATE_ERROR_WARNING;
    			can_id |= CAN_ERR_CRTL;
    			data1 |= CAN_ERR_CRTL_RX_WARNING;
    		} else {
    			new_state = CAN_STATE_ERROR_ACTIVE;
    		}
    
    		/* Update can state statistics */
    		switch (priv->can.state) {
    		case CAN_STATE_ERROR_ACTIVE:
    			if (new_state >= CAN_STATE_ERROR_WARNING &&
    			    new_state <= CAN_STATE_BUS_OFF)
    				priv->can.can_stats.error_warning++;
    		case CAN_STATE_ERROR_WARNING:	/* fallthrough */
    			if (new_state >= CAN_STATE_ERROR_PASSIVE &&
    			    new_state <= CAN_STATE_BUS_OFF)
    				priv->can.can_stats.error_passive++;
    			break;
    		default:
    			break;
    		}
    		priv->can.state = new_state;
    
    		if (intf & CANINTF_ERRIF) {
    			/* Handle overflow counters */
    			if (eflag & (EFLG_RX0OVR | EFLG_RX1OVR)) {
    				if (eflag & EFLG_RX0OVR) {
    					net->stats.rx_over_errors++;
    					net->stats.rx_errors++;
    				}
    				if (eflag & EFLG_RX1OVR) {
    					net->stats.rx_over_errors++;
    					net->stats.rx_errors++;
    				}
    				can_id |= CAN_ERR_CRTL;
    				data1 |= CAN_ERR_CRTL_RX_OVERFLOW;
    			}
    			mcp251x_error_skb(net, can_id, data1);
    		}
    
    		if (priv->can.state == CAN_STATE_BUS_OFF) {
    			if (priv->can.restart_ms == 0) {
    				priv->force_quit = 1;
    				priv->can.can_stats.bus_off++;
    				can_bus_off(net);
    				mcp251x_hw_sleep(spi);
    				break;
    			}
    		}
    
    		if (intf == 0)
    			break;
    
    		if (intf & CANINTF_TX) {
    			net->stats.tx_packets++;
    			net->stats.tx_bytes += priv->tx_len - 1;
    			can_led_event(net, CAN_LED_EVENT_TX);
    			if (priv->tx_len) {
    				can_get_echo_skb(net, 0);
    				priv->tx_len = 0;
    			}
    			netif_wake_queue(net);
    		}
    
    	}
    	mutex_unlock(&priv->mcp_lock);
    	return IRQ_HANDLED;
    }
    
    static int mcp251x_open(struct net_device *net)
    {
    	struct mcp251x_priv *priv = netdev_priv(net);
    	struct spi_device *spi = priv->spi;
    	unsigned long flags = IRQF_ONESHOT | IRQF_TRIGGER_FALLING;
    	int ret;
    
    	ret = open_candev(net);
    	if (ret) {
    		dev_err(&spi->dev, "unable to set initial baudrate!\n");
    		return ret;
    	}
    
    	mutex_lock(&priv->mcp_lock);
    	mcp251x_power_enable(priv->transceiver, 1);
    
    	priv->force_quit = 0;
    	priv->tx_skb = NULL;
    	priv->tx_len = 0;
    
    	ret = request_threaded_irq(spi->irq, NULL, mcp251x_can_ist,
    				   flags | IRQF_ONESHOT, DEVICE_NAME, priv);
    	if (ret) {
    		dev_err(&spi->dev, "failed to acquire irq %d\n", spi->irq);
    		goto out_close;
    	}
    
    	priv->wq = alloc_workqueue("mcp251x_wq", WQ_FREEZABLE | WQ_MEM_RECLAIM,
    				   0);
    	if (!priv->wq) {
    		ret = -ENOMEM;
    		goto out_clean;
    	}
    	INIT_WORK(&priv->tx_work, mcp251x_tx_work_handler);
    	INIT_WORK(&priv->restart_work, mcp251x_restart_work_handler);
    
    	ret = mcp251x_hw_reset(spi);
    	if (ret)
    		goto out_free_wq;
    	ret = mcp251x_setup(net, spi);
    	if (ret)
    		goto out_free_wq;
    	ret = mcp251x_set_normal_mode(spi);
    	if (ret)
    		goto out_free_wq;
    
    	can_led_event(net, CAN_LED_EVENT_OPEN);
    
    	netif_wake_queue(net);
    	mutex_unlock(&priv->mcp_lock);
    
    	return 0;
    
    out_free_wq:
    	destroy_workqueue(priv->wq);
    out_clean:
    	free_irq(spi->irq, priv);
    	mcp251x_hw_sleep(spi);
    out_close:
    	mcp251x_power_enable(priv->transceiver, 0);
    	close_candev(net);
    	mutex_unlock(&priv->mcp_lock);
    	return ret;
    }
    
    static const struct net_device_ops mcp251x_netdev_ops = {
    	.ndo_open = mcp251x_open,
    	.ndo_stop = mcp251x_stop,
    	.ndo_start_xmit = mcp251x_hard_start_xmit,
    	.ndo_change_mtu = can_change_mtu,
    };
    
    static const struct of_device_id mcp251x_of_match[] = {
    	{
    		.compatible	= "microchip,mcp2510",
    		.data		= (void *)CAN_MCP251X_MCP2510,
    	},
    	{
    		.compatible	= "microchip,mcp2515",
    		.data		= (void *)CAN_MCP251X_MCP2515,
    	},
    	{
    		.compatible	= "microchip,mcp25625",
    		.data		= (void *)CAN_MCP251X_MCP25625,
    	},
    	{ }
    };
    MODULE_DEVICE_TABLE(of, mcp251x_of_match);
    
    static const struct spi_device_id mcp251x_id_table[] = {
    	{
    		.name		= "mcp2510",
    		.driver_data	= (kernel_ulong_t)CAN_MCP251X_MCP2510,
    	},
    	{
    		.name		= "mcp2515",
    		.driver_data	= (kernel_ulong_t)CAN_MCP251X_MCP2515,
    	},
    	{
    		.name		= "mcp25625",
    		.driver_data	= (kernel_ulong_t)CAN_MCP251X_MCP25625,
    	},
    	{ }
    };
    MODULE_DEVICE_TABLE(spi, mcp251x_id_table);
    
    static int mcp251x_can_probe(struct spi_device *spi)
    {
    	const struct of_device_id *of_id = of_match_device(mcp251x_of_match,
    							   &spi->dev);
    	struct mcp251x_platform_data *pdata = dev_get_platdata(&spi->dev);
    	struct net_device *net;
    	struct mcp251x_priv *priv;
    	struct clk *clk;
    	int freq, ret;
    
    	clk = devm_clk_get(&spi->dev, NULL);
    	if (IS_ERR(clk)) {
    		if (pdata)
    			freq = pdata->oscillator_frequency;
    		else
    			return PTR_ERR(clk);
    	} else {
    		freq = clk_get_rate(clk);
    	}
    
    	/* Sanity check */
    	if (freq < 1000000 || freq > 25000000)
    		return -ERANGE;
    
    	/* Allocate can/net device */
    	net = alloc_candev(sizeof(struct mcp251x_priv), TX_ECHO_SKB_MAX);
    	if (!net)
    		return -ENOMEM;
    
    	if (!IS_ERR(clk)) {
    		ret = clk_prepare_enable(clk);
    		if (ret)
    			goto out_free;
    	}
    
    	net->netdev_ops = &mcp251x_netdev_ops;
    	net->flags |= IFF_ECHO;
    
    	priv = netdev_priv(net);
    	priv->can.bittiming_const = &mcp251x_bittiming_const;
    	priv->can.do_set_mode = mcp251x_do_set_mode;
    	priv->can.clock.freq = freq / 2;
    	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
    		CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_LISTENONLY;
    	if (of_id)
    		priv->model = (enum mcp251x_model)of_id->data;
    	else
    		priv->model = spi_get_device_id(spi)->driver_data;
    	priv->net = net;
    	priv->clk = clk;
    
    	spi_set_drvdata(spi, priv);
    
    	/* Configure the SPI bus */
    	spi->bits_per_word = 8;
    	if (mcp251x_is_2510(spi))
    		spi->max_speed_hz = spi->max_speed_hz ? : 5 * 1000 * 1000;
    	else
    		spi->max_speed_hz = spi->max_speed_hz ? : 10 * 1000 * 1000;
    	ret = spi_setup(spi);
    	if (ret)
    		goto out_clk;
    
    	priv->power = devm_regulator_get_optional(&spi->dev, "vdd");
    	priv->transceiver = devm_regulator_get_optional(&spi->dev, "xceiver");
    	if ((PTR_ERR(priv->power) == -EPROBE_DEFER) ||
    	    (PTR_ERR(priv->transceiver) == -EPROBE_DEFER)) {
    		ret = -EPROBE_DEFER;
    		goto out_clk;
    	}
    
    	ret = mcp251x_power_enable(priv->power, 1);
    	if (ret)
    		goto out_clk;
    
    	priv->spi = spi;
    	mutex_init(&priv->mcp_lock);
    
    	/* If requested, allocate DMA buffers */
    	if (mcp251x_enable_dma) {
    		spi->dev.coherent_dma_mask = ~0;
    
    		/*
    		 * Minimum coherent DMA allocation is PAGE_SIZE, so allocate
    		 * that much and share it between Tx and Rx DMA buffers.
    		 */
    		priv->spi_tx_buf = dmam_alloc_coherent(&spi->dev,
    						       PAGE_SIZE,
    						       &priv->spi_tx_dma,
    						       GFP_DMA);
    
    		if (priv->spi_tx_buf) {
    			priv->spi_rx_buf = (priv->spi_tx_buf + (PAGE_SIZE / 2));
    			priv->spi_rx_dma = (dma_addr_t)(priv->spi_tx_dma +
    							(PAGE_SIZE / 2));
    		} else {
    			/* Fall back to non-DMA */
    			mcp251x_enable_dma = 0;
    		}
    	}
    
    	/* Allocate non-DMA buffers */
    	if (!mcp251x_enable_dma) {
    		priv->spi_tx_buf = devm_kzalloc(&spi->dev, SPI_TRANSFER_BUF_LEN,
    						GFP_KERNEL);
    		if (!priv->spi_tx_buf) {
    			ret = -ENOMEM;
    			goto error_probe;
    		}
    		priv->spi_rx_buf = devm_kzalloc(&spi->dev, SPI_TRANSFER_BUF_LEN,
    						GFP_KERNEL);
    		if (!priv->spi_rx_buf) {
    			ret = -ENOMEM;
    			goto error_probe;
    		}
    	}
    
    	SET_NETDEV_DEV(net, &spi->dev);
    
    	/* Here is OK to not lock the MCP, no one knows about it yet */
    	ret = mcp251x_hw_probe(spi);
    	if (ret) {
    		if (ret == -ENODEV)
    			dev_err(&spi->dev, "Cannot initialize MCP%x. Wrong wiring?\n", priv->model);
    		goto error_probe;
    	}
    
    	mcp251x_hw_sleep(spi);
    
    	ret = register_candev(net);
    	if (ret)
    		goto error_probe;
    
    	devm_can_led_init(net);
    
    	netdev_info(net, "MCP%x successfully initialized.\n", priv->model);
    	return 0;
    
    error_probe:
    	mcp251x_power_enable(priv->power, 0);
    
    out_clk:
    	if (!IS_ERR(clk))
    		clk_disable_unprepare(clk);
    
    out_free:
    	free_candev(net);
    
    	dev_err(&spi->dev, "Probe failed, err=%d\n", -ret);
    	return ret;
    }
    
    static int mcp251x_can_remove(struct spi_device *spi)
    {
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    	struct net_device *net = priv->net;
    
    	unregister_candev(net);
    
    	mcp251x_power_enable(priv->power, 0);
    
    	if (!IS_ERR(priv->clk))
    		clk_disable_unprepare(priv->clk);
    
    	free_candev(net);
    
    	return 0;
    }
    
    static int __maybe_unused mcp251x_can_suspend(struct device *dev)
    {
    	struct spi_device *spi = to_spi_device(dev);
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    	struct net_device *net = priv->net;
    
    	priv->force_quit = 1;
    	disable_irq(spi->irq);
    	/*
    	 * Note: at this point neither IST nor workqueues are running.
    	 * open/stop cannot be called anyway so locking is not needed
    	 */
    	if (netif_running(net)) {
    		netif_device_detach(net);
    
    		mcp251x_hw_sleep(spi);
    		mcp251x_power_enable(priv->transceiver, 0);
    		priv->after_suspend = AFTER_SUSPEND_UP;
    	} else {
    		priv->after_suspend = AFTER_SUSPEND_DOWN;
    	}
    
    	if (!IS_ERR_OR_NULL(priv->power)) {
    		regulator_disable(priv->power);
    		priv->after_suspend |= AFTER_SUSPEND_POWER;
    	}
    
    	return 0;
    }
    
    static int __maybe_unused mcp251x_can_resume(struct device *dev)
    {
    	struct spi_device *spi = to_spi_device(dev);
    	struct mcp251x_priv *priv = spi_get_drvdata(spi);
    
    	if (priv->after_suspend & AFTER_SUSPEND_POWER)
    		mcp251x_power_enable(priv->power, 1);
    
    	if (priv->after_suspend & AFTER_SUSPEND_UP) {
    		mcp251x_power_enable(priv->transceiver, 1);
    		queue_work(priv->wq, &priv->restart_work);
    	} else {
    		priv->after_suspend = 0;
    	}
    
    	priv->force_quit = 0;
    	enable_irq(spi->irq);
    	return 0;
    }
    
    static SIMPLE_DEV_PM_OPS(mcp251x_can_pm_ops, mcp251x_can_suspend,
    	mcp251x_can_resume);
    
    static struct spi_driver mcp251x_can_driver = {
    	.driver = {
    		.name = DEVICE_NAME,
    		.of_match_table = mcp251x_of_match,
    		.pm = &mcp251x_can_pm_ops,
    	},
    	.id_table = mcp251x_id_table,
    	.probe = mcp251x_can_probe,
    	.remove = mcp251x_can_remove,
    };
    module_spi_driver(mcp251x_can_driver);
    
    MODULE_AUTHOR("Chris Elston <celston@katalix.com>, "
    	      "Christian Pellegrin <chripell@evolware.org>");
    MODULE_DESCRIPTION("Microchip 251x/25625 CAN driver");
    MODULE_LICENSE("GPL v2");
    

  • 另外CAN相关的调试工具有吗?比如canutils或者其它.

  • 安卓的驱动能不能参考其他家的IC代码修改一下,只改寄存器相关的内容?

    理解您的意思,但是这个我们没有实际验证过呢。

    另外CAN相关的调试工具有吗?比如canutils或者其它.

    很抱歉也没有呢。

  • 麻烦这里面的8个参数提供下

  • 这8个参数吗?

    可能无法帮助到您呢,建议您到英文E2E上咨询下美国工程师。