gpio: add MC33880 driver (1e5db006) · Commits · e / devices / android_kernel_teracube_2e

drivers/gpio/Kconfig

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		@@ -195,4 +195,11 @@ config GPIO_MCP23S08
		SPI driver for Microchip MCP23S08 I/O expander. This provides
		a GPIO interface supporting inputs and outputs.

		config GPIO_MC33880
		tristate "Freescale MC33880 high-side/low-side switch"
		depends on SPI_MASTER
		help
		SPI driver for Freescale MC33880 high-side/low-side switch.
		This provides GPIO interface supporting inputs and outputs.

		endif

drivers/gpio/Makefile

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		@@ -6,6 +6,7 @@ obj-$(CONFIG_GPIOLIB) += gpiolib.o

		obj-$(CONFIG_GPIO_MAX7301) += max7301.o
		obj-$(CONFIG_GPIO_MAX732X) += max732x.o
		obj-$(CONFIG_GPIO_MC33880) += mc33880.o
		obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o
		obj-$(CONFIG_GPIO_PCA953X) += pca953x.o
		obj-$(CONFIG_GPIO_PCF857X) += pcf857x.o

drivers/gpio/mc33880.c

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		/*
		* mc33880.c MC33880 high-side/low-side switch GPIO driver
		* Copyright (c) 2009 Intel Corporation
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 as
		* published by the Free Software Foundation.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to the Free Software
		* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
		*/

		/* Supports:
		* Freescale MC33880 high-side/low-side switch
		*/

		#include <linux/init.h>
		#include <linux/mutex.h>
		#include <linux/spi/spi.h>
		#include <linux/spi/mc33880.h>
		#include <linux/gpio.h>

		#define DRIVER_NAME "mc33880"

		/*
		* Pin configurations, see MAX7301 datasheet page 6
		*/
		#define PIN_CONFIG_MASK 0x03
		#define PIN_CONFIG_IN_PULLUP 0x03
		#define PIN_CONFIG_IN_WO_PULLUP 0x02
		#define PIN_CONFIG_OUT 0x01

		#define PIN_NUMBER 8


		/*
		* Some registers must be read back to modify.
		* To save time we cache them here in memory
		*/
		struct mc33880 {
		struct mutex lock; /* protect from simultanous accesses */
		u8 port_config;
		struct gpio_chip chip;
		struct spi_device *spi;
		};

		static int mc33880_write_config(struct mc33880 *mc)
		{
		return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config));
		}


		static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value)
		{
		if (value)
		mc->port_config \|= 1 << offset;
		else
		mc->port_config &= ~(1 << offset);

		return mc33880_write_config(mc);
		}


		static void mc33880_set(struct gpio_chip *chip, unsigned offset, int value)
		{
		struct mc33880 *mc = container_of(chip, struct mc33880, chip);

		mutex_lock(&mc->lock);

		__mc33880_set(mc, offset, value);

		mutex_unlock(&mc->lock);
		}

		static int __devinit mc33880_probe(struct spi_device *spi)
		{
		struct mc33880 *mc;
		struct mc33880_platform_data *pdata;
		int ret;

		pdata = spi->dev.platform_data;
		if (!pdata \|\| !pdata->base) {
		dev_dbg(&spi->dev, "incorrect or missing platform data\n");
		return -EINVAL;
		}

		/*
		* bits_per_word cannot be configured in platform data
		*/
		spi->bits_per_word = 8;

		ret = spi_setup(spi);
		if (ret < 0)
		return ret;

		mc = kzalloc(sizeof(struct mc33880), GFP_KERNEL);
		if (!mc)
		return -ENOMEM;

		mutex_init(&mc->lock);

		dev_set_drvdata(&spi->dev, mc);

		mc->spi = spi;

		mc->chip.label = DRIVER_NAME,
		mc->chip.set = mc33880_set;
		mc->chip.base = pdata->base;
		mc->chip.ngpio = PIN_NUMBER;
		mc->chip.can_sleep = 1;
		mc->chip.dev = &spi->dev;
		mc->chip.owner = THIS_MODULE;

		mc->port_config = 0x00;
		/* write twice, because during initialisation the first setting
		* is just for testing SPI communication, and the second is the
		* "real" configuration
		*/
		ret = mc33880_write_config(mc);
		mc->port_config = 0x00;
		if (!ret)
		ret = mc33880_write_config(mc);

		if (ret) {
		printk(KERN_ERR "Failed writing to " DRIVER_NAME ": %d\n", ret);
		goto exit_destroy;
		}

		ret = gpiochip_add(&mc->chip);
		if (ret)
		goto exit_destroy;

		return ret;

		exit_destroy:
		dev_set_drvdata(&spi->dev, NULL);
		mutex_destroy(&mc->lock);
		kfree(mc);
		return ret;
		}

		static int mc33880_remove(struct spi_device *spi)
		{
		struct mc33880 *mc;
		int ret;

		mc = dev_get_drvdata(&spi->dev);
		if (mc == NULL)
		return -ENODEV;

		dev_set_drvdata(&spi->dev, NULL);

		ret = gpiochip_remove(&mc->chip);
		if (!ret) {
		mutex_destroy(&mc->lock);
		kfree(mc);
		} else
		dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",
		ret);

		return ret;
		}

		static struct spi_driver mc33880_driver = {
		.driver = {
		.name = DRIVER_NAME,
		.owner = THIS_MODULE,
		},
		.probe = mc33880_probe,
		.remove = __devexit_p(mc33880_remove),
		};

		static int __init mc33880_init(void)
		{
		return spi_register_driver(&mc33880_driver);
		}
		/* register after spi postcore initcall and before
		* subsys initcalls that may rely on these GPIOs
		*/
		subsys_initcall(mc33880_init);

		static void __exit mc33880_exit(void)
		{
		spi_unregister_driver(&mc33880_driver);
		}
		module_exit(mc33880_exit);

		MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
		MODULE_LICENSE("GPL v2");

include/linux/spi/mc33880.h

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		#ifndef LINUX_SPI_MC33880_H
		#define LINUX_SPI_MC33880_H

		struct mc33880_platform_data {
		/* number assigned to the first GPIO */
		unsigned base;
		};

		#endif