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Commit 38ab18ca authored by Daniel Mack's avatar Daniel Mack Committed by Mark Brown
Browse files

spi: spi-gpio: Add DT bindings 



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

Signed-off-by: default avatarDaniel Mack <zonque@gmail.com>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent 161c2dd3

Documentation/devicetree/bindings/spi/spi-gpio.txt

0 → 100644
+29 −0
Original line number Diff line number Diff line 
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 */

	};

drivers/spi/spi-gpio.c

+96 −3
Original line number Diff line number Diff line
@@ -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 @@ spi_gpio_request(struct spi_gpio_platform_data *pdata, const char *label, 
	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),

};