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