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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                 if (gpio != -EPROBE_DEFER)
 94                         dev_err(&pdev->dev,
 95                                         "Failed to parse gpio property for data pin (%d)\n",
 96                                         gpio);
 97 
 98                 return gpio;
 99         }
100         pdata->pin = gpio;
101 
102         gpio = of_get_gpio(np, 1);
103         if (gpio == -EPROBE_DEFER)
104                 return gpio;
105         /* ignore other errors as the pullup gpio is optional */
106         pdata->ext_pullup_enable_pin = gpio;
107 
108         pdev->dev.platform_data = pdata;
109 
110         return 0;
111 }
112 
113 static int w1_gpio_probe(struct platform_device *pdev)
114 {
115         struct w1_bus_master *master;
116         struct w1_gpio_platform_data *pdata;
117         int err;
118 
119         if (of_have_populated_dt()) {
120                 err = w1_gpio_probe_dt(pdev);
121                 if (err < 0)
122                         return err;
123         }
124 
125         pdata = dev_get_platdata(&pdev->dev);
126 
127         if (!pdata) {
128                 dev_err(&pdev->dev, "No configuration data\n");
129                 return -ENXIO;
130         }
131 
132         master = devm_kzalloc(&pdev->dev, sizeof(struct w1_bus_master),
133                         GFP_KERNEL);
134         if (!master) {
135                 dev_err(&pdev->dev, "Out of memory\n");
136                 return -ENOMEM;
137         }
138 
139         err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
140         if (err) {
141                 dev_err(&pdev->dev, "gpio_request (pin) failed\n");
142                 return err;
143         }
144 
145         if (gpio_is_valid(pdata->ext_pullup_enable_pin)) {
146                 err = devm_gpio_request_one(&pdev->dev,
147                                 pdata->ext_pullup_enable_pin, GPIOF_INIT_LOW,
148                                 "w1 pullup");
149                 if (err < 0) {
150                         dev_err(&pdev->dev, "gpio_request_one "
151                                         "(ext_pullup_enable_pin) failed\n");
152                         return err;
153                 }
154         }
155 
156         master->data = pdata;
157         master->read_bit = w1_gpio_read_bit;
158 
159         if (pdata->is_open_drain) {
160                 gpio_direction_output(pdata->pin, 1);
161                 master->write_bit = w1_gpio_write_bit_val;
162         } else {
163                 gpio_direction_input(pdata->pin);
164                 master->write_bit = w1_gpio_write_bit_dir;
165                 master->set_pullup = w1_gpio_set_pullup;
166         }
167 
168         err = w1_add_master_device(master);
169         if (err) {
170                 dev_err(&pdev->dev, "w1_add_master device failed\n");
171                 return err;
172         }
173 
174         if (pdata->enable_external_pullup)
175                 pdata->enable_external_pullup(1);
176 
177         if (gpio_is_valid(pdata->ext_pullup_enable_pin))
178                 gpio_set_value(pdata->ext_pullup_enable_pin, 1);
179 
180         platform_set_drvdata(pdev, master);
181 
182         return 0;
183 }
184 
185 static int w1_gpio_remove(struct platform_device *pdev)
186 {
187         struct w1_bus_master *master = platform_get_drvdata(pdev);
188         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
189 
190         if (pdata->enable_external_pullup)
191                 pdata->enable_external_pullup(0);
192 
193         if (gpio_is_valid(pdata->ext_pullup_enable_pin))
194                 gpio_set_value(pdata->ext_pullup_enable_pin, 0);
195 
196         w1_remove_master_device(master);
197 
198         return 0;
199 }
200 
201 #ifdef CONFIG_PM
202 
203 static int w1_gpio_suspend(struct platform_device *pdev, pm_message_t state)
204 {
205         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
206 
207         if (pdata->enable_external_pullup)
208                 pdata->enable_external_pullup(0);
209 
210         return 0;
211 }
212 
213 static int w1_gpio_resume(struct platform_device *pdev)
214 {
215         struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
216 
217         if (pdata->enable_external_pullup)
218                 pdata->enable_external_pullup(1);
219 
220         return 0;
221 }
222 
223 #else
224 #define w1_gpio_suspend NULL
225 #define w1_gpio_resume  NULL
226 #endif
227 
228 static struct platform_driver w1_gpio_driver = {
229         .driver = {
230                 .name   = "w1-gpio",
231                 .owner  = THIS_MODULE,
232                 .of_match_table = of_match_ptr(w1_gpio_dt_ids),
233         },
234         .probe = w1_gpio_probe,
235         .remove = w1_gpio_remove,
236         .suspend = w1_gpio_suspend,
237         .resume = w1_gpio_resume,
238 };
239 
240 module_platform_driver(w1_gpio_driver);
241 
242 MODULE_DESCRIPTION("GPIO w1 bus master driver");
243 MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
244 MODULE_LICENSE("GPL");
245 

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