1 files changed, 53 insertions, 34 deletions

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 09c9a1edb2c6..474d5a7fa95e 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -64,8 +64,7 @@ struct spi_imx_data;
 struct spi_imx_devtype_data {
 	void (*intctrl)(struct spi_imx_data *, int);
 	int (*prepare_message)(struct spi_imx_data *, struct spi_message *);
-	int (*prepare_transfer)(struct spi_imx_data *, struct spi_device *,
-				struct spi_transfer *);
+	int (*prepare_transfer)(struct spi_imx_data *, struct spi_device *);
 	void (*trigger)(struct spi_imx_data *);
 	int (*rx_available)(struct spi_imx_data *);
 	void (*reset)(struct spi_imx_data *);
@@ -498,8 +497,10 @@ static int mx51_ecspi_prepare_message(struct spi_imx_data *spi_imx,
 				      struct spi_message *msg)
 {
 	struct spi_device *spi = msg->spi;
+	struct spi_transfer *xfer;
 	u32 ctrl = MX51_ECSPI_CTRL_ENABLE;
-	u32 testreg;
+	u32 min_speed_hz = ~0U;
+	u32 testreg, delay;
 	u32 cfg = readl(spi_imx->base + MX51_ECSPI_CONFIG);
 
 	/* set Master or Slave mode */
@@ -560,15 +561,43 @@ static int mx51_ecspi_prepare_message(struct spi_imx_data *spi_imx,
 
 	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
+	 * SCLK clock, but we will wait two SCLK clock just to be sure. The
+	 * effect of the delay it takes for the hardware to apply changes
+	 * is noticable if the SCLK clock run very slow. In such a case, if
+	 * the polarity of SCLK should be inverted, the GPIO ChipSelect might
+	 * be asserted before the SCLK polarity changes, which would disrupt
+	 * the SPI communication as the device on the other end would consider
+	 * the change of SCLK polarity as a clock tick already.
+	 *
+	 * Because spi_imx->spi_bus_clk is only set in bitbang prepare_message
+	 * callback, iterate over all the transfers in spi_message, find the
+	 * one with lowest bus frequency, and use that bus frequency for the
+	 * delay calculation. In case all transfers have speed_hz == 0, then
+	 * min_speed_hz is ~0 and the resulting delay is zero.
+	 */
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		if (!xfer->speed_hz)
+			continue;
+		min_speed_hz = min(xfer->speed_hz, min_speed_hz);
+	}
+
+	delay = (2 * 1000000) / min_speed_hz;
+	if (likely(delay < 10))	/* SCLK is faster than 100 kHz */
+		udelay(delay);
+	else			/* SCLK is _very_ slow */
+		usleep_range(delay, delay + 10);
+
 	return 0;
 }
 
 static int mx51_ecspi_prepare_transfer(struct spi_imx_data *spi_imx,
-				       struct spi_device *spi,
-				       struct spi_transfer *t)
+				       struct spi_device *spi)
 {
 	u32 ctrl = readl(spi_imx->base + MX51_ECSPI_CTRL);
-	u32 clk = t->speed_hz, delay;
+	u32 clk;
 
 	/* Clear BL field and set the right value */
 	ctrl &= ~MX51_ECSPI_CTRL_BL_MASK;
@@ -582,7 +611,7 @@ static int mx51_ecspi_prepare_transfer(struct spi_imx_data *spi_imx,
 	/* set clock speed */
 	ctrl &= ~(0xf << MX51_ECSPI_CTRL_POSTDIV_OFFSET |
 		  0xf << MX51_ECSPI_CTRL_PREDIV_OFFSET);
-	ctrl |= mx51_ecspi_clkdiv(spi_imx, t->speed_hz, &clk);
+	ctrl |= mx51_ecspi_clkdiv(spi_imx, spi_imx->spi_bus_clk, &clk);
 	spi_imx->spi_bus_clk = clk;
 
 	if (spi_imx->usedma)
@@ -590,23 +619,6 @@ static int mx51_ecspi_prepare_transfer(struct spi_imx_data *spi_imx,
 
 	writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
 
-	/*
-	 * Wait until the changes in the configuration register CONFIGREG
-	 * propagate into the hardware. It takes exactly one tick of the
-	 * SCLK clock, but we will wait two SCLK clock just to be sure. The
-	 * effect of the delay it takes for the hardware to apply changes
-	 * is noticable if the SCLK clock run very slow. In such a case, if
-	 * the polarity of SCLK should be inverted, the GPIO ChipSelect might
-	 * be asserted before the SCLK polarity changes, which would disrupt
-	 * the SPI communication as the device on the other end would consider
-	 * the change of SCLK polarity as a clock tick already.
-	 */
-	delay = (2 * 1000000) / clk;
-	if (likely(delay < 10))	/* SCLK is faster than 100 kHz */
-		udelay(delay);
-	else			/* SCLK is _very_ slow */
-		usleep_range(delay, delay + 10);
-
 	return 0;
 }
 
@@ -694,13 +706,12 @@ static int mx31_prepare_message(struct spi_imx_data *spi_imx,
 }
 
 static int mx31_prepare_transfer(struct spi_imx_data *spi_imx,
-				 struct spi_device *spi,
-				 struct spi_transfer *t)
+				 struct spi_device *spi)
 {
 	unsigned int reg = MX31_CSPICTRL_ENABLE | MX31_CSPICTRL_MASTER;
 	unsigned int clk;
 
-	reg |= spi_imx_clkdiv_2(spi_imx->spi_clk, t->speed_hz, &clk) <<
+	reg |= spi_imx_clkdiv_2(spi_imx->spi_clk, spi_imx->spi_bus_clk, &clk) <<
 		MX31_CSPICTRL_DR_SHIFT;
 	spi_imx->spi_bus_clk = clk;
 
@@ -799,14 +810,13 @@ static int mx21_prepare_message(struct spi_imx_data *spi_imx,
 }
 
 static int mx21_prepare_transfer(struct spi_imx_data *spi_imx,
-				 struct spi_device *spi,
-				 struct spi_transfer *t)
+				 struct spi_device *spi)
 {
 	unsigned int reg = MX21_CSPICTRL_ENABLE | MX21_CSPICTRL_MASTER;
 	unsigned int max = is_imx27_cspi(spi_imx) ? 16 : 18;
 	unsigned int clk;
 
-	reg |= spi_imx_clkdiv_1(spi_imx->spi_clk, t->speed_hz, max, &clk)
+	reg |= spi_imx_clkdiv_1(spi_imx->spi_clk, spi_imx->spi_bus_clk, max, &clk)
 		<< MX21_CSPICTRL_DR_SHIFT;
 	spi_imx->spi_bus_clk = clk;
 
@@ -875,13 +885,12 @@ static int mx1_prepare_message(struct spi_imx_data *spi_imx,
 }
 
 static int mx1_prepare_transfer(struct spi_imx_data *spi_imx,
-				struct spi_device *spi,
-				struct spi_transfer *t)
+				struct spi_device *spi)
 {
 	unsigned int reg = MX1_CSPICTRL_ENABLE | MX1_CSPICTRL_MASTER;
 	unsigned int clk;
 
-	reg |= spi_imx_clkdiv_2(spi_imx->spi_clk, t->speed_hz, &clk) <<
+	reg |= spi_imx_clkdiv_2(spi_imx->spi_clk, spi_imx->spi_bus_clk, &clk) <<
 		MX1_CSPICTRL_DR_SHIFT;
 	spi_imx->spi_bus_clk = clk;
 
@@ -1199,6 +1208,16 @@ static int spi_imx_setupxfer(struct spi_device *spi,
 	if (!t)
 		return 0;
 
+	if (!t->speed_hz) {
+		if (!spi->max_speed_hz) {
+			dev_err(&spi->dev, "no speed_hz provided!\n");
+			return -EINVAL;
+		}
+		dev_dbg(&spi->dev, "using spi->max_speed_hz!\n");
+		spi_imx->spi_bus_clk = spi->max_speed_hz;
+	} else
+		spi_imx->spi_bus_clk = t->speed_hz;
+
 	spi_imx->bits_per_word = t->bits_per_word;
 
 	/*
@@ -1240,7 +1259,7 @@ static int spi_imx_setupxfer(struct spi_device *spi,
 		spi_imx->slave_burst = t->len;
 	}
 
-	spi_imx->devtype_data->prepare_transfer(spi_imx, spi, t);
+	spi_imx->devtype_data->prepare_transfer(spi_imx, spi);
 
 	return 0;
 }