[PATCH v1 1/1] spi: tegra20_slink: fix CS polarity setup

[Svyatoslav Ryhel]

Add missing configuration of chip select polarity. Default polarity is LOW,
which satisfies most cases but some devices require HIGH polarity and will
not work.

Signed-off-by: Svyatoslav Ryhel <clamor95 at gmail.com>
---
 drivers/spi/tegra20_slink.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/spi/tegra20_slink.c b/drivers/spi/tegra20_slink.c
index d54a5049205..097d9164175 100644
--- a/drivers/spi/tegra20_slink.c
+++ b/drivers/spi/tegra20_slink.c
@@ -29,7 +29,10 @@ DECLARE_GLOBAL_DATA_PTR;
 #define SLINK_CMD_IDLE_SCLK_PULL_LOW	(2 << 24)
 #define SLINK_CMD_IDLE_SCLK_PULL_HIGH	(3 << 24)
 #define SLINK_CMD_IDLE_SCLK_MASK	(3 << 24)
+#define SLINK_CMD_CS_POL3		BIT(23)
+#define SLINK_CMD_CS_POL2		BIT(22)
 #define SLINK_CMD_CK_SDA		BIT(21)
+#define SLINK_CMD_CS_POL1		BIT(20)
 #define SLINK_CMD_CS_POL		BIT(13)
 #define SLINK_CMD_CS_VAL		BIT(12)
 #define SLINK_CMD_CS_SOFT		BIT(11)
@@ -64,6 +67,13 @@ DECLARE_GLOBAL_DATA_PTR;
 #define SPI_TIMEOUT		1000
 #define TEGRA_SPI_MAX_FREQ	52000000
 
+unsigned int cmd_cs_pol_bit[] = {
+	SLINK_CMD_CS_POL,
+	SLINK_CMD_CS_POL1,
+	SLINK_CMD_CS_POL2,
+	SLINK_CMD_CS_POL3,
+};
+
 struct spi_regs {
 	u32 command;	/* SLINK_COMMAND_0 register  */
 	u32 command2;	/* SLINK_COMMAND2_0 reg */
@@ -155,6 +165,14 @@ static int tegra30_spi_claim_bus(struct udevice *dev)
 	writel(reg, &regs->status);
 	debug("%s: STATUS = %08x\n", __func__, readl(&regs->status));
 
+	/* Update the polarity bits */
+	if (priv->mode & SPI_CS_HIGH)
+		setbits_le32(&priv->regs->command,
+			     cmd_cs_pol_bit[spi_chip_select(dev)]);
+	else
+		clrbits_le32(&priv->regs->command,
+			     cmd_cs_pol_bit[spi_chip_select(dev)]);
+
 	/* Set master mode and sw controlled CS */
 	reg = readl(&regs->command);
 	reg |= SLINK_CMD_M_S | SLINK_CMD_CS_SOFT;
-- 
2.43.0