w1-gpio: add GPIO w1 bus master driver (ad8dc96e) · Commits · 戴 / test

Documentation/w1/masters/00-INDEX

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		@@ -4,3 +4,5 @@ ds2482
		- The Maxim/Dallas Semiconductor DS2482 provides 1-wire busses.
		ds2490
		- 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
		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

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-$(CONFIG_W1_MASTER_DS2482) += ds2482.o
		obj-$(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");

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