LXR 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/w1-gpio.h>
  15
  16#include "../w1.h"
  17#include "../w1_int.h"
  18
  19#include <asm/gpio.h>
  20
  21static void w1_gpio_write_bit_dir(void *data, u8 bit)
  22{
  23        struct w1_gpio_platform_data *pdata = data;
  24
  25        if (bit)
  26                gpio_direction_input(pdata->pin);
  27        else
  28                gpio_direction_output(pdata->pin, 0);
  29}
  30
  31static void w1_gpio_write_bit_val(void *data, u8 bit)
  32{
  33        struct w1_gpio_platform_data *pdata = data;
  34
  35        gpio_set_value(pdata->pin, bit);
  36}
  37
  38static u8 w1_gpio_read_bit(void *data)
  39{
  40        struct w1_gpio_platform_data *pdata = data;
  41
  42        return gpio_get_value(pdata->pin) ? 1 : 0;
  43}
  44
  45static int __init w1_gpio_probe(struct platform_device *pdev)
  46{
  47        struct w1_bus_master *master;
  48        struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
  49        int err;
  50
  51        if (!pdata)
  52                return -ENXIO;
  53
  54        master = kzalloc(sizeof(struct w1_bus_master), GFP_KERNEL);
  55        if (!master)
  56                return -ENOMEM;
  57
  58        err = gpio_request(pdata->pin, "w1");
  59        if (err)
  60                goto free_master;
  61
  62        master->data = pdata;
  63        master->read_bit = w1_gpio_read_bit;
  64
  65        if (pdata->is_open_drain) {
  66                gpio_direction_output(pdata->pin, 1);
  67                master->write_bit = w1_gpio_write_bit_val;
  68        } else {
  69                gpio_direction_input(pdata->pin);
  70                master->write_bit = w1_gpio_write_bit_dir;
  71        }
  72
  73        err = w1_add_master_device(master);
  74        if (err)
  75                goto free_gpio;
  76
  77        if (pdata->enable_external_pullup)
  78                pdata->enable_external_pullup(1);
  79
  80        platform_set_drvdata(pdev, master);
  81
  82        return 0;
  83
  84 free_gpio:
  85        gpio_free(pdata->pin);
  86 free_master:
  87        kfree(master);
  88
  89        return err;
  90}
  91
  92static int __exit w1_gpio_remove(struct platform_device *pdev)
  93{
  94        struct w1_bus_master *master = platform_get_drvdata(pdev);
  95        struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
  96
  97        if (pdata->enable_external_pullup)
  98                pdata->enable_external_pullup(0);
  99
 100        w1_remove_master_device(master);
 101        gpio_free(pdata->pin);
 102        kfree(master);
 103
 104        return 0;
 105}
 106
 107#ifdef CONFIG_PM
 108
 109static int w1_gpio_suspend(struct platform_device *pdev, pm_message_t state)
 110{
 111        struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
 112
 113        if (pdata->enable_external_pullup)
 114                pdata->enable_external_pullup(0);
 115
 116        return 0;
 117}
 118
 119static int w1_gpio_resume(struct platform_device *pdev)
 120{
 121        struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
 122
 123        if (pdata->enable_external_pullup)
 124                pdata->enable_external_pullup(1);
 125
 126        return 0;
 127}
 128
 129#else
 130#define w1_gpio_suspend NULL
 131#define w1_gpio_resume  NULL
 132#endif
 133
 134static struct platform_driver w1_gpio_driver = {
 135        .driver = {
 136                .name   = "w1-gpio",
 137                .owner  = THIS_MODULE,
 138        },
 139        .remove = __exit_p(w1_gpio_remove),
 140        .suspend = w1_gpio_suspend,
 141        .resume = w1_gpio_resume,
 142};
 143
 144static int __init w1_gpio_init(void)
 145{
 146        return platform_driver_probe(&w1_gpio_driver, w1_gpio_probe);
 147}
 148
 149static void __exit w1_gpio_exit(void)
 150{
 151        platform_driver_unregister(&w1_gpio_driver);
 152}
 153
 154module_init(w1_gpio_init);
 155module_exit(w1_gpio_exit);
 156
 157MODULE_DESCRIPTION("GPIO w1 bus master driver");
 158MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
 159MODULE_LICENSE("GPL");
 160