2 * w1-gpio - GPIO w1 bus master driver
4 * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
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.
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/slab.h>
15 #include <linux/w1-gpio.h>
16 #include <linux/gpio.h>
17 #include <linux/of_platform.h>
18 #include <linux/of_gpio.h>
21 #include "../w1_int.h"
23 static void w1_gpio_write_bit_dir(void *data, u8 bit)
25 struct w1_gpio_platform_data *pdata = data;
28 gpio_direction_input(pdata->pin);
30 gpio_direction_output(pdata->pin, 0);
33 static void w1_gpio_write_bit_val(void *data, u8 bit)
35 struct w1_gpio_platform_data *pdata = data;
37 gpio_set_value(pdata->pin, bit);
40 static u8 w1_gpio_read_bit(void *data)
42 struct w1_gpio_platform_data *pdata = data;
44 return gpio_get_value(pdata->pin) ? 1 : 0;
48 static struct of_device_id w1_gpio_dt_ids[] = {
49 { .compatible = "w1-gpio" },
52 MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
54 static int w1_gpio_probe_dt(struct platform_device *pdev)
56 struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
57 struct device_node *np = pdev->dev.of_node;
58 const struct of_device_id *of_id =
59 of_match_device(w1_gpio_dt_ids, &pdev->dev);
64 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
68 if (of_get_property(np, "linux,open-drain", NULL))
69 pdata->is_open_drain = 1;
71 pdata->pin = of_get_gpio(np, 0);
72 pdata->ext_pullup_enable_pin = of_get_gpio(np, 1);
73 pdev->dev.platform_data = pdata;
78 static int w1_gpio_probe_dt(struct platform_device *pdev)
84 static int __init w1_gpio_probe(struct platform_device *pdev)
86 struct w1_bus_master *master;
87 struct w1_gpio_platform_data *pdata;
90 err = w1_gpio_probe_dt(pdev);
94 pdata = pdev->dev.platform_data;
99 master = kzalloc(sizeof(struct w1_bus_master), GFP_KERNEL);
103 err = gpio_request(pdata->pin, "w1");
107 if (gpio_is_valid(pdata->ext_pullup_enable_pin)) {
108 err = gpio_request_one(pdata->ext_pullup_enable_pin,
109 GPIOF_INIT_LOW, "w1 pullup");
114 master->data = pdata;
115 master->read_bit = w1_gpio_read_bit;
117 if (pdata->is_open_drain) {
118 gpio_direction_output(pdata->pin, 1);
119 master->write_bit = w1_gpio_write_bit_val;
121 gpio_direction_input(pdata->pin);
122 master->write_bit = w1_gpio_write_bit_dir;
125 err = w1_add_master_device(master);
127 goto free_gpio_ext_pu;
129 if (pdata->enable_external_pullup)
130 pdata->enable_external_pullup(1);
132 if (gpio_is_valid(pdata->ext_pullup_enable_pin))
133 gpio_set_value(pdata->ext_pullup_enable_pin, 1);
135 platform_set_drvdata(pdev, master);
140 if (gpio_is_valid(pdata->ext_pullup_enable_pin))
141 gpio_free(pdata->ext_pullup_enable_pin);
143 gpio_free(pdata->pin);
150 static int __exit w1_gpio_remove(struct platform_device *pdev)
152 struct w1_bus_master *master = platform_get_drvdata(pdev);
153 struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
155 if (pdata->enable_external_pullup)
156 pdata->enable_external_pullup(0);
158 if (gpio_is_valid(pdata->ext_pullup_enable_pin))
159 gpio_set_value(pdata->ext_pullup_enable_pin, 0);
161 w1_remove_master_device(master);
162 gpio_free(pdata->pin);
170 static int w1_gpio_suspend(struct platform_device *pdev, pm_message_t state)
172 struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
174 if (pdata->enable_external_pullup)
175 pdata->enable_external_pullup(0);
180 static int w1_gpio_resume(struct platform_device *pdev)
182 struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
184 if (pdata->enable_external_pullup)
185 pdata->enable_external_pullup(1);
191 #define w1_gpio_suspend NULL
192 #define w1_gpio_resume NULL
195 static struct platform_driver w1_gpio_driver = {
198 .owner = THIS_MODULE,
199 .of_match_table = of_match_ptr(w1_gpio_dt_ids),
201 .remove = __exit_p(w1_gpio_remove),
202 .suspend = w1_gpio_suspend,
203 .resume = w1_gpio_resume,
206 static int __init w1_gpio_init(void)
208 return platform_driver_probe(&w1_gpio_driver, w1_gpio_probe);
211 static void __exit w1_gpio_exit(void)
213 platform_driver_unregister(&w1_gpio_driver);
216 module_init(w1_gpio_init);
217 module_exit(w1_gpio_exit);
219 MODULE_DESCRIPTION("GPIO w1 bus master driver");
220 MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
221 MODULE_LICENSE("GPL");