w1-gpio: add GPIO w1 bus master driver

Add a GPIO 1-wire bus master driver. The driver used the GPIO API to control the wire and the GPIO pin can be specified using platform data similar to i2c-gpio. The driver was tested with AT91SAM9260 + DS2401. Signed-off-by: Ville Syrjala <syrjala@sci.fi> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

w1-gpio: add GPIO w1 bus master driver
Add a GPIO 1-wire bus master driver. The driver used the GPIO API to control the wire and the GPIO pin can be specified using platform data similar to i2c-gpio. The driver was tested with AT91SAM9260 + DS2401. Signed-off-by: Ville Syrjala <syrjala@sci.fi> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ville Syrjala · Linus Torvalds
1 parent 4cdf854f7d
Showing 6 changed files with 193 additions and 0 deletions Side-by-side Diff
Documentation/w1/masters/00-INDEX
Documentation/w1/masters/w1-gpio
drivers/w1/masters/Kconfig
drivers/w1/masters/Makefile
drivers/w1/masters/w1-gpio.c
include/linux/w1-gpio.h
@@ -4,4 +4,6 @@
 	- 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.
+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);
@@ -42,5 +42,15 @@
 	  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
@@ -6,4 +6,5 @@
 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
+/*
+ * 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");
+/*
+ * w1-gpio interface to platform code
+ *
+ * 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.
+ */
+#ifndef _LINUX_W1_GPIO_H
+#define _LINUX_W1_GPIO_H
+
+/**
+ * struct w1_gpio_platform_data - Platform-dependent data for w1-gpio
+ * @pin: GPIO pin to use
+ * @is_open_drain: GPIO pin is configured as open drain
+ */
+struct w1_gpio_platform_data {
+	unsigned int pin;
+	unsigned int is_open_drain:1;
+};
+
+#endif /* _LINUX_W1_GPIO_H */
...	...	@@ -4,4 +4,6 @@
4	4	- The Maxim/Dallas Semiconductor DS2482 provides 1-wire busses.
5	5	ds2490
6	6	- The Maxim/Dallas Semiconductor DS2490 builds USB <-> W1 bridges.
	7	+w1-gpio
	8	+ - GPIO 1-wire bus master driver.
	1	+Kernel driver w1-gpio
	2	+=====================
	3	+
	4	+Author: Ville Syrjala <syrjala@sci.fi>
	5	+
	6	+
	7	+Description
	8	+-----------
	9	+
	10	+GPIO 1-wire bus master driver. The driver uses the GPIO API to control the
	11	+wire and the GPIO pin can be specified using platform data.
	12	+
	13	+
	14	+Example (mach-at91)
	15	+-------------------
	16	+
	17	+#include <linux/w1-gpio.h>
	18	+
	19	+static struct w1_gpio_platform_data foo_w1_gpio_pdata = {
	20	+ .pin = AT91_PIN_PB20,
	21	+ .is_open_drain = 1,
	22	+};
	23	+
	24	+static struct platform_device foo_w1_device = {
	25	+ .name = "w1-gpio",
	26	+ .id = -1,
	27	+ .dev.platform_data = &foo_w1_gpio_pdata,
	28	+};
	29	+
	30	+...
	31	+ at91_set_GPIO_periph(foo_w1_gpio_pdata.pin, 1);
	32	+ at91_set_multi_drive(foo_w1_gpio_pdata.pin, 1);
	33	+ platform_device_register(&foo_w1_device);
...	...	@@ -42,5 +42,15 @@
42	42	in HP iPAQ devices like h5xxx, h2200, and ASIC3-based like
43	43	hx4700.
44	44
	45	+config W1_MASTER_GPIO
	46	+ tristate "GPIO 1-wire busmaster"
	47	+ depends on GENERIC_GPIO
	48	+ help
	49	+ Say Y here if you want to communicate with your 1-wire devices using
	50	+ GPIO pins. This driver uses the GPIO API to control the wire.
	51	+
	52	+ This support is also available as a module. If so, the module
	53	+ will be called w1-gpio.ko.
	54	+
45	55	endmenu
...	...	@@ -6,4 +6,5 @@
6	6	obj-$(CONFIG_W1_MASTER_DS2490) += ds2490.o
7	7	obj-$(CONFIG_W1_MASTER_DS2482) += ds2482.o
8	8	obj-$(CONFIG_W1_MASTER_DS1WM) += ds1wm.o
	9	+obj-$(CONFIG_W1_MASTER_GPIO) += w1-gpio.o
	1	+/*
	2	+ * w1-gpio - GPIO w1 bus master driver
	3	+ *
	4	+ * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
	5	+ *
	6	+ * This program is free software; you can redistribute it and/or modify
	7	+ * it under the terms of the GNU General Public License version 2
	8	+ * as published by the Free Software Foundation.
	9	+ */
	10	+
	11	+#include <linux/init.h>
	12	+#include <linux/module.h>
	13	+#include <linux/platform_device.h>
	14	+#include <linux/w1-gpio.h>
	15	+
	16	+#include "../w1.h"
	17	+#include "../w1_int.h"
	18	+
	19	+#include <asm/gpio.h>
	20	+
	21	+static void w1_gpio_write_bit_dir(void *data, u8 bit)
	22	+{
	23	+ struct w1_gpio_platform_data *pdata = data;
	24	+
	25	+ if (bit)
	26	+ gpio_direction_input(pdata->pin);
	27	+ else
	28	+ gpio_direction_output(pdata->pin, 0);
	29	+}
	30	+
	31	+static void w1_gpio_write_bit_val(void *data, u8 bit)
	32	+{
	33	+ struct w1_gpio_platform_data *pdata = data;
	34	+
	35	+ gpio_set_value(pdata->pin, bit);
	36	+}
	37	+
	38	+static u8 w1_gpio_read_bit(void *data)
	39	+{
	40	+ struct w1_gpio_platform_data *pdata = data;
	41	+
	42	+ return gpio_get_value(pdata->pin);
	43	+}
	44	+
	45	+static int __init w1_gpio_probe(struct platform_device *pdev)
	46	+{
	47	+ struct w1_bus_master *master;
	48	+ struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
	49	+ int err;
	50	+
	51	+ if (!pdata)
	52	+ return -ENXIO;
	53	+
	54	+ master = kzalloc(sizeof(struct w1_bus_master), GFP_KERNEL);
	55	+ if (!master)
	56	+ return -ENOMEM;
	57	+
	58	+ err = gpio_request(pdata->pin, "w1");
	59	+ if (err)
	60	+ goto free_master;
	61	+
	62	+ master->data = pdata;
	63	+ master->read_bit = w1_gpio_read_bit;
	64	+
	65	+ if (pdata->is_open_drain) {
	66	+ gpio_direction_output(pdata->pin, 1);
	67	+ master->write_bit = w1_gpio_write_bit_val;
	68	+ } else {
	69	+ gpio_direction_input(pdata->pin);
	70	+ master->write_bit = w1_gpio_write_bit_dir;
	71	+ }
	72	+
	73	+ err = w1_add_master_device(master);
	74	+ if (err)
	75	+ goto free_gpio;
	76	+
	77	+ platform_set_drvdata(pdev, master);
	78	+
	79	+ return 0;
	80	+
	81	+ free_gpio:
	82	+ gpio_free(pdata->pin);
	83	+ free_master:
	84	+ kfree(master);
	85	+
	86	+ return err;
	87	+}
	88	+
	89	+static int __exit w1_gpio_remove(struct platform_device *pdev)
	90	+{
	91	+ struct w1_bus_master *master = platform_get_drvdata(pdev);
	92	+ struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
	93	+
	94	+ w1_remove_master_device(master);
	95	+ gpio_free(pdata->pin);
	96	+ kfree(master);
	97	+
	98	+ return 0;
	99	+}
	100	+
	101	+static struct platform_driver w1_gpio_driver = {
	102	+ .driver = {
	103	+ .name = "w1-gpio",
	104	+ .owner = THIS_MODULE,
	105	+ },
	106	+ .remove = __exit_p(w1_gpio_remove),
	107	+};
	108	+
	109	+static int __init w1_gpio_init(void)
	110	+{
	111	+ return platform_driver_probe(&w1_gpio_driver, w1_gpio_probe);
	112	+}
	113	+
	114	+static void __exit w1_gpio_exit(void)
	115	+{
	116	+ platform_driver_unregister(&w1_gpio_driver);
	117	+}
	118	+
	119	+module_init(w1_gpio_init);
	120	+module_exit(w1_gpio_exit);
	121	+
	122	+MODULE_DESCRIPTION("GPIO w1 bus master driver");
	123	+MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
	124	+MODULE_LICENSE("GPL");
	1	+/*
	2	+ * w1-gpio interface to platform code
	3	+ *
	4	+ * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
	5	+ *
	6	+ * This program is free software; you can redistribute it and/or modify
	7	+ * it under the terms of the GNU General Public License version 2
	8	+ * as published by the Free Software Foundation.
	9	+ */
	10	+#ifndef _LINUX_W1_GPIO_H
	11	+#define _LINUX_W1_GPIO_H
	12	+
	13	+/**
	14	+ * struct w1_gpio_platform_data - Platform-dependent data for w1-gpio
	15	+ * @pin: GPIO pin to use
	16	+ * @is_open_drain: GPIO pin is configured as open drain
	17	+ */
	18	+struct w1_gpio_platform_data {
	19	+ unsigned int pin;
	20	+ unsigned int is_open_drain:1;
	21	+};
	22	+
	23	+#endif /* _LINUX_W1_GPIO_H */