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>
19 #include <linux/err.h>
21 #include <linux/delay.h>
25 static u8 w1_gpio_set_pullup(void *data, int delay)
27 struct w1_gpio_platform_data *pdata = data;
30 pdata->pullup_duration = delay;
32 if (pdata->pullup_duration) {
33 gpio_direction_output(pdata->pin, 1);
35 msleep(pdata->pullup_duration);
37 gpio_direction_input(pdata->pin);
39 pdata->pullup_duration = 0;
45 static void w1_gpio_write_bit_dir(void *data, u8 bit)
47 struct w1_gpio_platform_data *pdata = data;
50 gpio_direction_input(pdata->pin);
52 gpio_direction_output(pdata->pin, 0);
55 static void w1_gpio_write_bit_val(void *data, u8 bit)
57 struct w1_gpio_platform_data *pdata = data;
59 gpio_set_value(pdata->pin, bit);
62 static u8 w1_gpio_read_bit(void *data)
64 struct w1_gpio_platform_data *pdata = data;
66 return gpio_get_value(pdata->pin) ? 1 : 0;
69 #if defined(CONFIG_OF)
70 static const struct of_device_id w1_gpio_dt_ids[] = {
71 { .compatible = "w1-gpio" },
74 MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
77 static int w1_gpio_probe_dt(struct platform_device *pdev)
79 struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
80 struct device_node *np = pdev->dev.of_node;
83 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
87 if (of_get_property(np, "linux,open-drain", NULL))
88 pdata->is_open_drain = 1;
90 gpio = of_get_gpio(np, 0);
92 if (gpio != -EPROBE_DEFER)
94 "Failed to parse gpio property for data pin (%d)\n",
101 gpio = of_get_gpio(np, 1);
102 if (gpio == -EPROBE_DEFER)
104 /* ignore other errors as the pullup gpio is optional */
105 pdata->ext_pullup_enable_pin = gpio;
107 pdev->dev.platform_data = pdata;
112 static int w1_gpio_probe(struct platform_device *pdev)
114 struct w1_bus_master *master;
115 struct w1_gpio_platform_data *pdata;
118 if (of_have_populated_dt()) {
119 err = w1_gpio_probe_dt(pdev);
124 pdata = dev_get_platdata(&pdev->dev);
127 dev_err(&pdev->dev, "No configuration data\n");
131 master = devm_kzalloc(&pdev->dev, sizeof(struct w1_bus_master),
134 dev_err(&pdev->dev, "Out of memory\n");
138 err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
140 dev_err(&pdev->dev, "gpio_request (pin) failed\n");
144 if (gpio_is_valid(pdata->ext_pullup_enable_pin)) {
145 err = devm_gpio_request_one(&pdev->dev,
146 pdata->ext_pullup_enable_pin, GPIOF_INIT_LOW,
149 dev_err(&pdev->dev, "gpio_request_one "
150 "(ext_pullup_enable_pin) failed\n");
155 master->data = pdata;
156 master->read_bit = w1_gpio_read_bit;
158 if (pdata->is_open_drain) {
159 gpio_direction_output(pdata->pin, 1);
160 master->write_bit = w1_gpio_write_bit_val;
162 gpio_direction_input(pdata->pin);
163 master->write_bit = w1_gpio_write_bit_dir;
164 master->set_pullup = w1_gpio_set_pullup;
167 err = w1_add_master_device(master);
169 dev_err(&pdev->dev, "w1_add_master device failed\n");
173 if (pdata->enable_external_pullup)
174 pdata->enable_external_pullup(1);
176 if (gpio_is_valid(pdata->ext_pullup_enable_pin))
177 gpio_set_value(pdata->ext_pullup_enable_pin, 1);
179 platform_set_drvdata(pdev, master);
184 static int w1_gpio_remove(struct platform_device *pdev)
186 struct w1_bus_master *master = platform_get_drvdata(pdev);
187 struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
189 if (pdata->enable_external_pullup)
190 pdata->enable_external_pullup(0);
192 if (gpio_is_valid(pdata->ext_pullup_enable_pin))
193 gpio_set_value(pdata->ext_pullup_enable_pin, 0);
195 w1_remove_master_device(master);
200 static int __maybe_unused w1_gpio_suspend(struct device *dev)
202 struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
204 if (pdata->enable_external_pullup)
205 pdata->enable_external_pullup(0);
210 static int __maybe_unused w1_gpio_resume(struct device *dev)
212 struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
214 if (pdata->enable_external_pullup)
215 pdata->enable_external_pullup(1);
220 static SIMPLE_DEV_PM_OPS(w1_gpio_pm_ops, w1_gpio_suspend, w1_gpio_resume);
222 static struct platform_driver w1_gpio_driver = {
225 .pm = &w1_gpio_pm_ops,
226 .of_match_table = of_match_ptr(w1_gpio_dt_ids),
228 .probe = w1_gpio_probe,
229 .remove = w1_gpio_remove,
232 module_platform_driver(w1_gpio_driver);
234 MODULE_DESCRIPTION("GPIO w1 bus master driver");
235 MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
236 MODULE_LICENSE("GPL");