spi: spi-gpio: store chipselect information in private structure

The spi-gpio driver currently assumes the chipselect gpio number is
stored in ->controller_data of the device's static board information.

In devicetree environments, this information is unavailable and has to
be derived from the DT node.

This patch moves the gpio storage to the controller's private data so
the DT bindings can easily build upon the driver.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/spi/spi-gpio.c

@@ -46,6 +46,7 @@ struct spi_gpio {
 	struct spi_bitbang		bitbang;
 	struct spi_gpio_platform_data	pdata;
 	struct platform_device		*pdev;
+	int				cs_gpios[0];
 };
 
 /*----------------------------------------------------------------------*/
@@ -89,15 +90,21 @@ struct spi_gpio {
 
 /*----------------------------------------------------------------------*/
 
-static inline const struct spi_gpio_platform_data * __pure
-spi_to_pdata(const struct spi_device *spi)
+static inline struct spi_gpio * __pure
+spi_to_spi_gpio(const struct spi_device *spi)
 {
 	const struct spi_bitbang	*bang;
-	const struct spi_gpio		*spi_gpio;
+	struct spi_gpio			*spi_gpio;
 
 	bang = spi_master_get_devdata(spi->master);
 	spi_gpio = container_of(bang, struct spi_gpio, bitbang);
-	return &spi_gpio->pdata;
+	return spi_gpio;
+}
+
+static inline struct spi_gpio_platform_data * __pure
+spi_to_pdata(const struct spi_device *spi)
+{
+	return &spi_to_spi_gpio(spi)->pdata;
 }
 
 /* this is #defined to avoid unused-variable warnings when inlining */
@@ -210,7 +217,8 @@ static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi,
 
 static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
 {
-	unsigned long cs = (unsigned long) spi->controller_data;
+	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
+	unsigned int cs = spi_gpio->cs_gpios[spi->chip_select];
 
 	/* set initial clock polarity */
 	if (is_active)
@@ -224,8 +232,9 @@ static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
 
 static int spi_gpio_setup(struct spi_device *spi)
 {
-	unsigned long	cs = (unsigned long) spi->controller_data;
-	int		status = 0;
+	unsigned int		cs = (unsigned int) spi->controller_data;
+	int			status = 0;
+	struct spi_gpio		*spi_gpio = spi_to_spi_gpio(spi);
 
 	if (spi->bits_per_word > 32)
 		return -EINVAL;
@@ -239,8 +248,11 @@ static int spi_gpio_setup(struct spi_device *spi)
 					!(spi->mode & SPI_CS_HIGH));
 		}
 	}
-	if (!status)
+	if (!status) {
 		status = spi_bitbang_setup(spi);
+		spi_gpio->cs_gpios[spi->chip_select] = cs;
+	}
+
 	if (status) {
 		if (!spi->controller_state && cs != SPI_GPIO_NO_CHIPSELECT)
 			gpio_free(cs);
@@ -250,7 +262,8 @@ static int spi_gpio_setup(struct spi_device *spi)
 
 static void spi_gpio_cleanup(struct spi_device *spi)
 {
-	unsigned long	cs = (unsigned long) spi->controller_data;
+	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
+	unsigned int cs = spi_gpio->cs_gpios[spi->chip_select];
 
 	if (cs != SPI_GPIO_NO_CHIPSELECT)
 		gpio_free(cs);
@@ -331,7 +344,8 @@ static int __devinit spi_gpio_probe(struct platform_device *pdev)
 	if (status < 0)
 		return status;
 
-	master = spi_alloc_master(&pdev->dev, sizeof *spi_gpio);
+	master = spi_alloc_master(&pdev->dev, sizeof(*spi_gpio) +
+					(sizeof(int) * SPI_N_CHIPSEL));
 	if (!master) {
 		status = -ENOMEM;
 		goto gpio_free;