Version:  2.6.34 2.6.35 2.6.36 2.6.37 2.6.38 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14

Linux/drivers/w1/masters/w1-gpio.c

  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/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>
 20 #include <linux/of.h>
 21 #include <linux/delay.h>
 22 
 23 #include "../w1.h"
 24 #include "../w1_int.h"
 25 
 26 static u8 w1_gpio_set_pullup(void *data, int delay)
 27 {
 28         struct w1_gpio_platform_data *pdata = data;
 29 
 30         if (delay) {
 31                 pdata->pullup_duration = delay;
 32         } else {
 33                 if (pdata->pullup_duration) {
 34                         gpio_direction_output(pdata->pin, 1);
 35 
 36                         msleep(pdata->pullup_duration);
 37 
 38                         gpio_direction_input(pdata->pin);
 39                 }
 40                 pdata->pullup_duration = 0;
 41         }
 42 
 43         return 0;
 44 }
 45 
 46 static void w1_gpio_write_bit_dir(void *data, u8 bit)
 47 {
 48         struct w1_gpio_platform_data *pdata = data;
 49 
 50         if (bit)
 51                 gpio_direction_input(pdata->pin);
 52         else
 53                 gpio_direction_output(pdata->pin, 0);
 54 }
 55 
 56 static void w1_gpio_write_bit_val(void *data, u8 bit)
 57 {
 58         struct w1_gpio_platform_data *pdata = data;
 59 
 60         gpio_set_value(pdata->pin, bit);
 61 }
 62 
 63 static u8 w1_gpio_read_bit(void *data)
 64 {
 65         struct w1_gpio_platform_data *pdata = data;
 66 
 67         return gpio_get_value(pdata->pin) ? 1 : 0;
 68 }
 69 
 70 #if defined(CONFIG_OF)
 71 static struct of_device_id w1_gpio_dt_ids[] = {
 72         { .compatible = "w1-gpio" },
 73         {}
 74 };
 75 MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
 76 #endif
 77 
 78 static int w1_gpio_probe_dt(struct platform_device *pdev)
 79 {
 80         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
 81         struct device_node *np = pdev->dev.of_node;
 82         int gpio;
 83 
 84         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 85         if (!pdata)
 86                 return -ENOMEM;
 87 
 88         if (of_get_property(np, "linux,open-drain", NULL))
 89                 pdata->is_open_drain = 1;
 90 
 91         gpio = of_get_gpio(np, 0);
 92         if (gpio < 0)
 93                 return gpio;
 94         pdata->pin = gpio;
 95 
 96         pdata->ext_pullup_enable_pin = of_get_gpio(np, 1);
 97         pdev->dev.platform_data = pdata;
 98 
 99         return 0;
100 }
101 
102 static int w1_gpio_probe(struct platform_device *pdev)
103 {
104         struct w1_bus_master *master;
105         struct w1_gpio_platform_data *pdata;
106         int err;
107 
108         if (of_have_populated_dt()) {
109                 err = w1_gpio_probe_dt(pdev);
110                 if (err < 0) {
111                         dev_err(&pdev->dev, "Failed to parse DT\n");
112                         return err;
113                 }
114         }
115 
116         pdata = dev_get_platdata(&pdev->dev);
117 
118         if (!pdata) {
119                 dev_err(&pdev->dev, "No configuration data\n");
120                 return -ENXIO;
121         }
122 
123         master = devm_kzalloc(&pdev->dev, sizeof(struct w1_bus_master),
124                         GFP_KERNEL);
125         if (!master) {
126                 dev_err(&pdev->dev, "Out of memory\n");
127                 return -ENOMEM;
128         }
129 
130         err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
131         if (err) {
132                 dev_err(&pdev->dev, "gpio_request (pin) failed\n");
133                 return err;
134         }
135 
136         if (gpio_is_valid(pdata->ext_pullup_enable_pin)) {
137                 err = devm_gpio_request_one(&pdev->dev,
138                                 pdata->ext_pullup_enable_pin, GPIOF_INIT_LOW,
139                                 "w1 pullup");
140                 if (err < 0) {
141                         dev_err(&pdev->dev, "gpio_request_one "
142                                         "(ext_pullup_enable_pin) failed\n");
143                         return err;
144                 }
145         }
146 
147         master->data = pdata;
148         master->read_bit = w1_gpio_read_bit;
149 
150         if (pdata->is_open_drain) {
151                 gpio_direction_output(pdata->pin, 1);
152                 master->write_bit = w1_gpio_write_bit_val;
153         } else {
154                 gpio_direction_input(pdata->pin);
155                 master->write_bit = w1_gpio_write_bit_dir;
156                 master->set_pullup = w1_gpio_set_pullup;
157         }
158 
159         err = w1_add_master_device(master);
160         if (err) {
161                 dev_err(&pdev->dev, "w1_add_master device failed\n");
162                 return err;
163         }
164 
165         if (pdata->enable_external_pullup)
166                 pdata->enable_external_pullup(1);
167 
168         if (gpio_is_valid(pdata->ext_pullup_enable_pin))
169                 gpio_set_value(pdata->ext_pullup_enable_pin, 1);
170 
171         platform_set_drvdata(pdev, master);
172 
173         return 0;
174 }
175 
176 static int w1_gpio_remove(struct platform_device *pdev)
177 {
178         struct w1_bus_master *master = platform_get_drvdata(pdev);
179         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
180 
181         if (pdata->enable_external_pullup)
182                 pdata->enable_external_pullup(0);
183 
184         if (gpio_is_valid(pdata->ext_pullup_enable_pin))
185                 gpio_set_value(pdata->ext_pullup_enable_pin, 0);
186 
187         w1_remove_master_device(master);
188 
189         return 0;
190 }
191 
192 #ifdef CONFIG_PM
193 
194 static int w1_gpio_suspend(struct platform_device *pdev, pm_message_t state)
195 {
196         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
197 
198         if (pdata->enable_external_pullup)
199                 pdata->enable_external_pullup(0);
200 
201         return 0;
202 }
203 
204 static int w1_gpio_resume(struct platform_device *pdev)
205 {
206         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
207 
208         if (pdata->enable_external_pullup)
209                 pdata->enable_external_pullup(1);
210 
211         return 0;
212 }
213 
214 #else
215 #define w1_gpio_suspend NULL
216 #define w1_gpio_resume  NULL
217 #endif
218 
219 static struct platform_driver w1_gpio_driver = {
220         .driver = {
221                 .name   = "w1-gpio",
222                 .owner  = THIS_MODULE,
223                 .of_match_table = of_match_ptr(w1_gpio_dt_ids),
224         },
225         .probe = w1_gpio_probe,
226         .remove = w1_gpio_remove,
227         .suspend = w1_gpio_suspend,
228         .resume = w1_gpio_resume,
229 };
230 
231 module_platform_driver(w1_gpio_driver);
232 
233 MODULE_DESCRIPTION("GPIO w1 bus master driver");
234 MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
235 MODULE_LICENSE("GPL");
236 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us