w1-gpio: add GPIO w1 bus master driver (ad8dc96e) · Commits · e / devices / android_kernel_teracube_2e

Documentation/w1/masters/00-INDEX

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	@@ -4,3 +4,5 @@ ds2482
	- The Maxim/Dallas Semiconductor DS2482 provides 1-wire busses.		- The Maxim/Dallas Semiconductor DS2482 provides 1-wire busses.
	ds2490		ds2490
	- The Maxim/Dallas Semiconductor DS2490 builds USB <-> W1 bridges.		- The Maxim/Dallas Semiconductor DS2490 builds USB <-> W1 bridges.
			w1-gpio
			- GPIO 1-wire bus master driver.

Documentation/w1/masters/w1-gpio

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			Kernel driver w1-gpio
			=====================

			Author: Ville Syrjala <syrjala@sci.fi>


			Description
			-----------

			GPIO 1-wire bus master driver. The driver uses the GPIO API to control the
			wire and the GPIO pin can be specified using platform data.


			Example (mach-at91)
			-------------------

			#include <linux/w1-gpio.h>

			static struct w1_gpio_platform_data foo_w1_gpio_pdata = {
			.pin = AT91_PIN_PB20,
			.is_open_drain = 1,
			};

			static struct platform_device foo_w1_device = {
			.name = "w1-gpio",
			.id = -1,
			.dev.platform_data = &foo_w1_gpio_pdata,
			};

			...
			at91_set_GPIO_periph(foo_w1_gpio_pdata.pin, 1);
			at91_set_multi_drive(foo_w1_gpio_pdata.pin, 1);
			platform_device_register(&foo_w1_device);

drivers/w1/masters/Kconfig

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	@@ -42,5 +42,15 @@ config W1_MASTER_DS1WM
	in HP iPAQ devices like h5xxx, h2200, and ASIC3-based like		in HP iPAQ devices like h5xxx, h2200, and ASIC3-based like
	hx4700.		hx4700.

			config W1_MASTER_GPIO
			tristate "GPIO 1-wire busmaster"
			depends on GENERIC_GPIO
			help
			Say Y here if you want to communicate with your 1-wire devices using
			GPIO pins. This driver uses the GPIO API to control the wire.

			This support is also available as a module. If so, the module
			will be called w1-gpio.ko.

	endmenu		endmenu

drivers/w1/masters/Makefile

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	@@ -6,3 +6,4 @@ obj-$(CONFIG_W1_MASTER_MATROX) += matrox_w1.o
	obj-$(CONFIG_W1_MASTER_DS2490) += ds2490.o		obj-$(CONFIG_W1_MASTER_DS2490) += ds2490.o
	obj-$(CONFIG_W1_MASTER_DS2482) += ds2482.o		obj-$(CONFIG_W1_MASTER_DS2482) += ds2482.o
	obj-$(CONFIG_W1_MASTER_DS1WM) += ds1wm.o		obj-$(CONFIG_W1_MASTER_DS1WM) += ds1wm.o
			obj-$(CONFIG_W1_MASTER_GPIO) += w1-gpio.o

drivers/w1/masters/w1-gpio.c

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			/*
			* w1-gpio - GPIO w1 bus master driver
			*
			* Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
			*
			* 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.
			*/

			#include <linux/init.h>
			#include <linux/module.h>
			#include <linux/platform_device.h>
			#include <linux/w1-gpio.h>

			#include "../w1.h"
			#include "../w1_int.h"

			#include <asm/gpio.h>

			static void w1_gpio_write_bit_dir(void *data, u8 bit)
			{
			struct w1_gpio_platform_data *pdata = data;

			if (bit)
			gpio_direction_input(pdata->pin);
			else
			gpio_direction_output(pdata->pin, 0);
			}

			static void w1_gpio_write_bit_val(void *data, u8 bit)
			{
			struct w1_gpio_platform_data *pdata = data;

			gpio_set_value(pdata->pin, bit);
			}

			static u8 w1_gpio_read_bit(void *data)
			{
			struct w1_gpio_platform_data *pdata = data;

			return gpio_get_value(pdata->pin);
			}

			static int __init w1_gpio_probe(struct platform_device *pdev)
			{
			struct w1_bus_master *master;
			struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
			int err;

			if (!pdata)
			return -ENXIO;

			master = kzalloc(sizeof(struct w1_bus_master), GFP_KERNEL);
			if (!master)
			return -ENOMEM;

			err = gpio_request(pdata->pin, "w1");
			if (err)
			goto free_master;

			master->data = pdata;
			master->read_bit = w1_gpio_read_bit;

			if (pdata->is_open_drain) {
			gpio_direction_output(pdata->pin, 1);
			master->write_bit = w1_gpio_write_bit_val;
			} else {
			gpio_direction_input(pdata->pin);
			master->write_bit = w1_gpio_write_bit_dir;
			}

			err = w1_add_master_device(master);
			if (err)
			goto free_gpio;

			platform_set_drvdata(pdev, master);

			return 0;

			free_gpio:
			gpio_free(pdata->pin);
			free_master:
			kfree(master);

			return err;
			}

			static int __exit w1_gpio_remove(struct platform_device *pdev)
			{
			struct w1_bus_master *master = platform_get_drvdata(pdev);
			struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;

			w1_remove_master_device(master);
			gpio_free(pdata->pin);
			kfree(master);

			return 0;
			}

			static struct platform_driver w1_gpio_driver = {
			.driver = {
			.name = "w1-gpio",
			.owner = THIS_MODULE,
			},
			.remove = __exit_p(w1_gpio_remove),
			};

			static int __init w1_gpio_init(void)
			{
			return platform_driver_probe(&w1_gpio_driver, w1_gpio_probe);
			}

			static void __exit w1_gpio_exit(void)
			{
			platform_driver_unregister(&w1_gpio_driver);
			}

			module_init(w1_gpio_init);
			module_exit(w1_gpio_exit);

			MODULE_DESCRIPTION("GPIO w1 bus master driver");
			MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
			MODULE_LICENSE("GPL");