spi: davinci: add support to configure gpio cs through dt

Currently driver supports only configuration of GPIO CS through
platform data. This patch enhances the driver to configure GPIO
CS through DT. Also update the DT binding documentation to
reflect the availability of cs-gpios.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 56 insertions, 8 deletions

diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
index 2477af4bc1c7..ac4414e00bb9 100644
--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -30,6 +30,7 @@
 #include <linux/edma.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_gpio.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/spi_bitbang.h>
 #include <linux/slab.h>
@@ -207,17 +208,28 @@ static inline void clear_io_bits(void __iomem *addr, u32 bits)
 static void davinci_spi_chipselect(struct spi_device *spi, int value)
 {
 	struct davinci_spi *dspi;
+	struct device_node *np = spi->dev.of_node;
 	struct davinci_spi_platform_data *pdata;
+	struct spi_master *master = spi->master;
 	u8 chip_sel = spi->chip_select;
 	u16 spidat1 = CS_DEFAULT;
 	bool gpio_chipsel = false;
+	int gpio;
 
 	dspi = spi_master_get_devdata(spi->master);
 	pdata = &dspi->pdata;
 
-	if (pdata->chip_sel && chip_sel < pdata->num_chipselect &&
-				pdata->chip_sel[chip_sel] != SPI_INTERN_CS)
+	if (np && master->cs_gpios != NULL && spi->cs_gpio >= 0) {
+		/* SPI core parse and update master->cs_gpio */
 		gpio_chipsel = true;
+		gpio = spi->cs_gpio;
+	} else if (pdata->chip_sel &&
+		   chip_sel < pdata->num_chipselect &&
+		   pdata->chip_sel[chip_sel] != SPI_INTERN_CS) {
+		/* platform data defines chip_sel */
+		gpio_chipsel = true;
+		gpio = pdata->chip_sel[chip_sel];
+	}
 
 	/*
 	 * Board specific chip select logic decides the polarity and cs
@@ -225,9 +237,9 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value)
 	 */
 	if (gpio_chipsel) {
 		if (value == BITBANG_CS_ACTIVE)
-			gpio_set_value(pdata->chip_sel[chip_sel], 0);
+			gpio_set_value(gpio, 0);
 		else
-			gpio_set_value(pdata->chip_sel[chip_sel], 1);
+			gpio_set_value(gpio, 1);
 	} else {
 		if (value == BITBANG_CS_ACTIVE) {
 			spidat1 |= SPIDAT1_CSHOLD_MASK;
@@ -390,17 +402,41 @@ static int davinci_spi_setup(struct spi_device *spi)
 	int retval = 0;
 	struct davinci_spi *dspi;
 	struct davinci_spi_platform_data *pdata;
+	struct spi_master *master = spi->master;
+	struct device_node *np = spi->dev.of_node;
+	bool internal_cs = true;
 
 	dspi = spi_master_get_devdata(spi->master);
 	pdata = &dspi->pdata;
 
 	if (!(spi->mode & SPI_NO_CS)) {
-		if ((pdata->chip_sel == NULL) ||
-		    (pdata->chip_sel[spi->chip_select] == SPI_INTERN_CS))
-			set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select);
-
+		if (np && (master->cs_gpios != NULL) && (spi->cs_gpio >= 0)) {
+			unsigned long flags;
+
+			flags = GPIOF_DIR_OUT;
+			if (spi->mode & SPI_CS_HIGH)
+				flags |= GPIOF_INIT_LOW;
+			else
+				flags |= GPIOF_INIT_HIGH;
+			retval = gpio_request_one(spi->cs_gpio,
+						  flags, dev_name(&spi->dev));
+			if (retval) {
+				dev_err(&spi->dev,
+					"GPIO %d request failed (%d)\n",
+					spi->cs_gpio, retval);
+				return retval;
+			}
+			internal_cs = false;
+		} else if (pdata->chip_sel &&
+			   spi->chip_select < pdata->num_chipselect &&
+			   pdata->chip_sel[spi->chip_select] != SPI_INTERN_CS) {
+			internal_cs = false;
+		}
 	}
 
+	if (internal_cs)
+		set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select);
+
 	if (spi->mode & SPI_READY)
 		set_io_bits(dspi->base + SPIPC0, SPIPC0_SPIENA_MASK);
 
@@ -412,6 +448,15 @@ static int davinci_spi_setup(struct spi_device *spi)
 	return retval;
 }
 
+static void davinci_spi_cleanup(struct spi_device *spi)
+{
+	struct spi_master *master = spi->master;
+	struct device_node *np = spi->dev.of_node;
+
+	if (np && (master->cs_gpios != NULL) && (spi->cs_gpio >= 0))
+		gpio_free(spi->cs_gpio);
+}
+
 static int davinci_spi_check_error(struct davinci_spi *dspi, int int_status)
 {
 	struct device *sdev = dspi->bitbang.master->dev.parent;
@@ -810,6 +855,8 @@ static int spi_davinci_get_pdata(struct platform_device *pdev,
 
 	/*
 	 * default num_cs is 1 and all chipsel are internal to the chip
+	 * indicated by chip_sel being NULL or cs_gpios being NULL or
+	 * set to -ENOENT. num-cs includes internal as well as gpios.
 	 * indicated by chip_sel being NULL. GPIO based CS is not
 	 * supported yet in DT bindings.
 	 */
@@ -921,6 +968,7 @@ static int davinci_spi_probe(struct platform_device *pdev)
 	master->num_chipselect = pdata->num_chipselect;
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 16);
 	master->setup = davinci_spi_setup;
+	master->cleanup = davinci_spi_cleanup;
 
 	dspi->bitbang.chipselect = davinci_spi_chipselect;
 	dspi->bitbang.setup_transfer = davinci_spi_setup_transfer;