The relevant difference between prepare_message and config is that the
former is run before the CS signal is asserted. So the polarity of the
CLK line must be configured in prepare_message as an edge generated by
config might already result in a latch of the MOSI line.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
[ukleinek: backport to v4.14.x]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
---
drivers/spi/spi-imx.c | 59 ++++++++++++++++++++++++++-----------------
1 file changed, 36 insertions(+), 23 deletions(-)
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 3fdb0652429b..df18d07d544d 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -443,14 +443,9 @@ static void mx51_ecspi_trigger(struct spi_imx_data *spi_imx)
static int mx51_ecspi_prepare_message(struct spi_imx_data *spi_imx,
struct spi_message *msg)
{
- return 0;
-}
-
-static int mx51_ecspi_config(struct spi_device *spi)
-{
- struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
+ struct spi_device *spi = msg->spi;
u32 ctrl = MX51_ECSPI_CTRL_ENABLE;
- u32 clk = spi_imx->speed_hz, delay, reg;
+ u32 testreg;
u32 cfg = readl(spi_imx->base + MX51_ECSPI_CONFIG);
/*
@@ -468,14 +463,21 @@ static int mx51_ecspi_config(struct spi_device *spi)
if (spi->mode & SPI_READY)
ctrl |= MX51_ECSPI_CTRL_DRCTL(spi_imx->spi_drctl);
- /* set clock speed */
- ctrl |= mx51_ecspi_clkdiv(spi_imx, spi_imx->speed_hz, &clk);
- spi_imx->spi_bus_clk = clk;
-
/* set chip select to use */
ctrl |= MX51_ECSPI_CTRL_CS(spi->chip_select);
- ctrl |= (spi_imx->bits_per_word - 1) << MX51_ECSPI_CTRL_BL_OFFSET;
+ /*
+ * The ctrl register must be written first, with the EN bit set other
+ * registers must not be written to.
+ */
+ writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
+
+ testreg = readl(spi_imx->base + MX51_ECSPI_TESTREG);
+ if (spi->mode & SPI_LOOP)
+ testreg |= MX51_ECSPI_TESTREG_LBC;
+ else
+ testreg &= ~MX51_ECSPI_TESTREG_LBC;
+ writel(testreg, spi_imx->base + MX51_ECSPI_TESTREG);
cfg |= MX51_ECSPI_CONFIG_SBBCTRL(spi->chip_select);
@@ -491,26 +493,38 @@ static int mx51_ecspi_config(struct spi_device *spi)
cfg &= ~MX51_ECSPI_CONFIG_SCLKPOL(spi->chip_select);
cfg &= ~MX51_ECSPI_CONFIG_SCLKCTL(spi->chip_select);
}
+
if (spi->mode & SPI_CS_HIGH)
cfg |= MX51_ECSPI_CONFIG_SSBPOL(spi->chip_select);
else
cfg &= ~MX51_ECSPI_CONFIG_SSBPOL(spi->chip_select);
+ writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
+
+ return 0;
+}
+
+static int mx51_ecspi_config(struct spi_device *spi)
+{
+ struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
+ u32 ctrl = readl(spi_imx->base + MX51_ECSPI_CTRL);
+ u32 clk = spi_imx->speed_hz, delay;
+
+ /* Clear BL field and set the right value */
+ ctrl &= ~MX51_ECSPI_CTRL_BL_MASK;
+ ctrl |= (spi_imx->bits_per_word - 1) << MX51_ECSPI_CTRL_BL_OFFSET;
+
+ /* set clock speed */
+ ctrl &= ~(0xf << MX51_ECSPI_CTRL_POSTDIV_OFFSET |
+ 0xf << MX51_ECSPI_CTRL_PREDIV_OFFSET);
+ ctrl |= mx51_ecspi_clkdiv(spi_imx, spi_imx->speed_hz, &clk);
+ spi_imx->spi_bus_clk = clk;
+
if (spi_imx->usedma)
ctrl |= MX51_ECSPI_CTRL_SMC;
- /* CTRL register always go first to bring out controller from reset */
writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
- reg = readl(spi_imx->base + MX51_ECSPI_TESTREG);
- if (spi->mode & SPI_LOOP)
- reg |= MX51_ECSPI_TESTREG_LBC;
- else
- reg &= ~MX51_ECSPI_TESTREG_LBC;
- writel(reg, spi_imx->base + MX51_ECSPI_TESTREG);
-
- writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
-
/*
* Wait until the changes in the configuration register CONFIGREG
* propagate into the hardware. It takes exactly one tick of the
@@ -532,7 +546,6 @@ static int mx51_ecspi_config(struct spi_device *spi)
* Configure the DMA register: setup the watermark
* and enable DMA request.
*/
-
writel(MX51_ECSPI_DMA_RX_WML(spi_imx->wml) |
MX51_ECSPI_DMA_TX_WML(spi_imx->wml) |
MX51_ECSPI_DMA_RXT_WML(spi_imx->wml) |
--
2.19.2
