[PATCH RESEND-2 1/2] SPI: spi-gpio: store chipselect information in private structure

[PATCH RESEND-2 1/2] SPI: spi-gpio: store chipselect information in private structure

[Daniel Mack]

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-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/spi/spi-gpio.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index 0b56cfc..ff7263c 100644
--- a/drivers/spi/spi-gpio.c
+++ b/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;
-- 
1.7.11.4


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[PATCH RESEND-2 2/2] SPI: spi-gpio: Add DT bindings

[Daniel Mack]

This patch adds DT bindings to the spi-gpio driver and some
documentation about how to use it.

Signed-off-by: Daniel Mack <zonque-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 Documentation/devicetree/bindings/spi/spi-gpio.txt | 29 +++++++
 drivers/spi/spi-gpio.c                             | 99 +++++++++++++++++++++-
 2 files changed, 125 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/spi/spi-gpio.txt

diff --git a/Documentation/devicetree/bindings/spi/spi-gpio.txt b/Documentation/devicetree/bindings/spi/spi-gpio.txt
new file mode 100644
index 0000000..8a824be
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/spi-gpio.txt
@@ -0,0 +1,29 @@
+SPI-GPIO devicetree bindings
+
+Required properties:
+
+ - compatible: should be set to "spi-gpio"
+ - #address-cells: should be set to <0x1>
+ - ranges
+ - gpio-sck: GPIO spec for the SCK line to use
+ - gpio-miso: GPIO spec for the MISO line to use
+ - gpio-mosi: GPIO spec for the MOSI line to use
+ - cs-gpios: GPIOs to use for chipselect lines
+ - num-chipselects: number of chipselect lines
+
+Example:
+
+	spi {
+		compatible = "spi-gpio";
+		#address-cells = <0x1>;
+		ranges;
+
+		gpio-sck = <&gpio 95 0>;
+		gpio-miso = <&gpio 98 0>;
+		gpio-mosi = <&gpio 97 0>;
+		cs-gpios = <&gpio 125 0>;
+		num-chipselects = <1>;
+
+		/* clients */
+	};
+
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index ff7263c..aed1615 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -22,6 +22,8 @@
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/gpio.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
 
 #include <linux/spi/spi.h>
 #include <linux/spi/spi_bitbang.h>
@@ -232,13 +234,27 @@ static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
 
 static int spi_gpio_setup(struct spi_device *spi)
 {
-	unsigned int		cs = (unsigned int) spi->controller_data;
+	unsigned int		cs;
 	int			status = 0;
 	struct spi_gpio		*spi_gpio = spi_to_spi_gpio(spi);
+	struct device_node	*np = spi->master->dev.of_node;
 
 	if (spi->bits_per_word > 32)
 		return -EINVAL;
 
+	if (np) {
+		/*
+		 * In DT environments, the CS GPIOs have already been
+		 * initialized from the "cs-gpios" property of the node.
+		 */
+		cs = spi_gpio->cs_gpios[spi->chip_select];
+	} else {
+		/*
+		 * ... otherwise, take it from spi->controller_data
+		 */
+		cs = (unsigned int) spi->controller_data;
+	}
+
 	if (!spi->controller_state) {
 		if (cs != SPI_GPIO_NO_CHIPSELECT) {
 			status = gpio_request(cs, dev_name(&spi->dev));
@@ -250,6 +266,7 @@ static int spi_gpio_setup(struct spi_device *spi)
 	}
 	if (!status) {
 		status = spi_bitbang_setup(spi);
+		/* in case it was initialized from static board data */
 		spi_gpio->cs_gpios[spi->chip_select] = cs;
 	}
 
@@ -326,6 +343,55 @@ done:
 	return value;
 }
 
+#ifdef CONFIG_OF
+static struct of_device_id spi_gpio_dt_ids[] = {
+	{ .compatible = "spi-gpio" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, spi_gpio_dt_ids);
+
+static int spi_gpio_probe_dt(struct platform_device *pdev)
+{
+	int ret;
+	u32 tmp;
+	struct spi_gpio_platform_data	*pdata;
+	struct device_node *np = pdev->dev.of_node;
+	const struct of_device_id *of_id =
+			of_match_device(spi_gpio_dt_ids, &pdev->dev);
+
+	if (!of_id)
+		return 0;
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	pdata->sck = of_get_named_gpio(np, "gpio-sck", 0);
+	pdata->miso = of_get_named_gpio(np, "gpio-miso", 0);
+	pdata->mosi = of_get_named_gpio(np, "gpio-mosi", 0);
+
+	ret = of_property_read_u32(np, "num-chipselects", &tmp);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "num-chipselects property not found\n");
+		goto error_free;
+	}
+
+	pdata->num_chipselect = tmp;
+	pdev->dev.platform_data = pdata;
+
+	return 1;
+
+error_free:
+	devm_kfree(&pdev->dev, pdata);
+	return ret;
+}
+#else
+static inline int spi_probe_dt(struct platform_device *)
+{
+	return 0;
+}
+#endif
+
 static int __devinit spi_gpio_probe(struct platform_device *pdev)
 {
 	int				status;
@@ -333,6 +399,13 @@ static int __devinit spi_gpio_probe(struct platform_device *pdev)
 	struct spi_gpio			*spi_gpio;
 	struct spi_gpio_platform_data	*pdata;
 	u16 master_flags = 0;
+	bool use_of = 0;
+
+	status = spi_gpio_probe_dt(pdev);
+	if (status < 0)
+		return status;
+	if (status > 0)
+		use_of = 1;
 
 	pdata = pdev->dev.platform_data;
 #ifdef GENERIC_BITBANG
@@ -362,6 +435,23 @@ static int __devinit spi_gpio_probe(struct platform_device *pdev)
 	master->num_chipselect = SPI_N_CHIPSEL;
 	master->setup = spi_gpio_setup;
 	master->cleanup = spi_gpio_cleanup;
+#ifdef CONFIG_OF
+	master->dev.of_node = pdev->dev.of_node;
+
+	if (use_of) {
+		int i;
+		struct device_node *np = pdev->dev.of_node;
+
+		/*
+		 * In DT environments, take the CS GPIO from the "cs-gpios"
+		 * property of the node.
+		 */
+
+		for (i = 0; i < SPI_N_CHIPSEL; i++)
+			spi_gpio->cs_gpios[i] =
+				of_get_named_gpio(np, "cs-gpios", i);
+	}
+#endif
 
 	spi_gpio->bitbang.master = spi_master_get(master);
 	spi_gpio->bitbang.chipselect = spi_gpio_chipselect;
@@ -422,8 +512,11 @@ static int __devexit spi_gpio_remove(struct platform_device *pdev)
 MODULE_ALIAS("platform:" DRIVER_NAME);
 
 static struct platform_driver spi_gpio_driver = {
-	.driver.name	= DRIVER_NAME,
-	.driver.owner	= THIS_MODULE,
+	.driver = {
+		.name	= DRIVER_NAME,
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(spi_gpio_dt_ids),
+	},
 	.probe		= spi_gpio_probe,
 	.remove		= __devexit_p(spi_gpio_remove),
 };
-- 
1.7.11.4

Re: [PATCH RESEND-2 1/2] SPI: spi-gpio: store chipselect information in private structure

[Mark Brown]

On Wed, Sep 05, 2012 at 11:04:35AM +0200, Daniel Mack wrote:
> The spi-gpio driver currently assumes the chipselect gpio number is
> stored in ->controller_data of the device's static board information.

Applied both, thanks.