大家好：
用AM4378 UBOOT里面SPI初始化LCD，这个LCD是需要初始化的，我们在用逻辑分析仪查看代码发现在真正的SPI操作前，会有一个异常的波形（后面都是对的），造成LCD总是初始化不对， 在程序中 我们发现很大可能是omap3_spi_claim_bus影响的，但这个函数中的每一句做看了，似乎又没发现什么不对，请给予支持！
int omap3_spi_claim_bus(struct spi_slave *slave)
{
struct omap3_spi_slave *ds = to_omap3_spi(slave);
unsigned int conf, div = 0;
/* McSPI global module configuration */
/*
* setup when switching from (reset default) slave mode
* to single-channel master mode
*/
omap3_spi_reset(ds);
conf = readl(&ds->regs->modulctrl);
printf("<Debug log> Enter %s, at %d, conf = 0x%x\n", __func__, __LINE__, conf);
conf &= ~(OMAP3_MCSPI_MODULCTRL_STEST | OMAP3_MCSPI_MODULCTRL_MS);
//conf &= ~(OMAP3_MCSPI_MODULCTRL_MS);
conf |= OMAP3_MCSPI_MODULCTRL_SINGLE;
//conf |= OMAP3_MCSPI_MODULCTRL_PIN34;
printf("<Debug log> Enter %s, at %d, conf = 0x%x\n", __func__, __LINE__, conf);
writel(conf, &ds->regs->modulctrl);
/* McSPI individual channel configuration */
/* Calculate clock divisor. Valid range: 0x0 - 0xC ( /1 - /4096 ) */
if (ds->freq) {
while (div <= 0xC && (OMAP3_MCSPI_MAX_FREQ / (1 << div))
> ds->freq)
div++;
} else
div = 0xC;
conf = readl(&ds->regs->channel[ds->slave.cs].chconf);
printf("<Debug log> Enter %s, at %d, conf = 0x%x\n", __func__, __LINE__, conf);
/* standard 4-wire master mode: SCK, MOSI/out, MISO/in, nCS
* REVISIT: this controller could support SPI_3WIRE mode.
*/
#ifdef CONFIG_OMAP3_SPI_D0_D1_SWAPPED
/*
* Some boards have D0 wired as MOSI / D1 as MISO instead of
* The normal D0 as MISO / D1 as MOSI.
*/
conf &= ~OMAP3_MCSPI_CHCONF_DPE0;
conf |= OMAP3_MCSPI_CHCONF_IS|OMAP3_MCSPI_CHCONF_DPE1;
#else
conf &= ~(OMAP3_MCSPI_CHCONF_IS|OMAP3_MCSPI_CHCONF_DPE1);
conf |= OMAP3_MCSPI_CHCONF_DPE0;
#endif
/* wordlength */
conf &= ~OMAP3_MCSPI_CHCONF_WL_MASK;
conf |= (ds->slave.wordlen - 1) << 7;
/* set chipselect polarity; manage with FORCE */
if (!(ds->mode & SPI_CS_HIGH))
conf |= OMAP3_MCSPI_CHCONF_EPOL; /* active-low; normal */
else
conf &= ~OMAP3_MCSPI_CHCONF_EPOL;
/* set clock divisor */
conf &= ~OMAP3_MCSPI_CHCONF_CLKD_MASK;
conf |= div << 2;
/* set SPI mode 0..3 */
if (ds->mode & SPI_CPOL)
conf |= OMAP3_MCSPI_CHCONF_POL;
else
conf &= ~OMAP3_MCSPI_CHCONF_POL;
if (ds->mode & SPI_CPHA)
conf |= OMAP3_MCSPI_CHCONF_PHA;
else
conf &= ~OMAP3_MCSPI_CHCONF_PHA;
/* Transmit & receive mode */
conf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK;
conf |= OMAP3_MCSPI_CHCONF_TRM_TX_ONLY;
printf("<Debug log> Enter %s, at %d, conf = 0x%x\n", __func__, __LINE__, conf);
omap3_spi_write_chconf(ds,conf);
return 0;
}
int lcd_init(u32 bus, u32 cs)
{
struct spi_slave *spi;
int err;
spi = omap3_spi_setup_slave(bus, cs, 1000000, SPI_MODE_2);
if (!spi) {
printf("Invalid device %d:%d\n", bus, cs);
return 1;
}
err = omap3_spi_claim_bus(spi);
if(err)
goto bus_claim_fail;
omap3_spi_start(spi);
assignment(spi, Set_EXTC, sizeof(Set_EXTC)/sizeof(u8));
omap3_spi_stop(spi);
msleep(2);
omap3_spi_start(spi);
assignment(spi, Set_POWER, sizeof(Set_POWER)/sizeof(u8));
omap3_spi_stop(spi);
msleep(2);
omap3_spi_start(spi);
assignment(spi, Set_SleepOut, sizeof(Set_SleepOut)/sizeof(u8));
omap3_spi_stop(spi);
msleep(150);
}
