drivers/leds/leds-gpio.c

   1 /*
   2  * LEDs driver for GPIOs
   3  *
   4  * Copyright (C) 2007 8D Technologies inc.
   5  * Raphael Assenat <raph@8d.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  */
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/leds.h>
  16 #include <linux/workqueue.h>
  17
  18 #include <asm/gpio.h>
  19
  20 struct gpio_led_data {
  21         struct led_classdev cdev;
  22         unsigned gpio;
  23         struct work_struct work;
  24         u8 new_level;
  25         u8 can_sleep;
  26         u8 active_low;
  27         int (*platform_gpio_blink_set)(unsigned gpio,
  28                         unsigned long *delay_on, unsigned long *delay_off);
  29 };
  30
  31 static void gpio_led_work(struct work_struct *work)
  32 {
  33         struct gpio_led_data    *led_dat =
  34                 container_of(work, struct gpio_led_data, work);
  35
  36         gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
  37 }
  38
  39 static void gpio_led_set(struct led_classdev *led_cdev,
  40         enum led_brightness value)
  41 {
  42         struct gpio_led_data *led_dat =
  43                 container_of(led_cdev, struct gpio_led_data, cdev);
  44         int level;
  45
  46         if (value == LED_OFF)
  47                 level = 0;
  48         else
  49                 level = 1;
  50
  51         if (led_dat->active_low)
  52                 level = !level;
  53
  54         /* Setting GPIOs with I2C/etc requires a task context, and we don't
  55          * seem to have a reliable way to know if we're already in one; so
  56          * let's just assume the worst.
  57          */
  58         if (led_dat->can_sleep) {
  59                 led_dat->new_level = level;
  60                 schedule_work(&led_dat->work);
  61         } else
  62                 gpio_set_value(led_dat->gpio, level);
  63 }
  64
  65 static int gpio_blink_set(struct led_classdev *led_cdev,
  66         unsigned long *delay_on, unsigned long *delay_off)
  67 {
  68         struct gpio_led_data *led_dat =
  69                 container_of(led_cdev, struct gpio_led_data, cdev);
  70
  71         return led_dat->platform_gpio_blink_set(led_dat->gpio, delay_on, delay_off);
  72 }
  73
  74 static int gpio_led_probe(struct platform_device *pdev)
  75 {
  76         struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
  77         struct gpio_led *cur_led;
  78         struct gpio_led_data *leds_data, *led_dat;
  79         int i, ret = 0;
  80
  81         if (!pdata)
  82                 return -EBUSY;
  83
  84         leds_data = kzalloc(sizeof(struct gpio_led_data) * pdata->num_leds,
  85                                 GFP_KERNEL);
  86         if (!leds_data)
  87                 return -ENOMEM;
  88
  89         for (i = 0; i < pdata->num_leds; i++) {
  90                 cur_led = &pdata->leds[i];
  91                 led_dat = &leds_data[i];
  92
  93                 ret = gpio_request(cur_led->gpio, cur_led->name);
  94                 if (ret < 0)
  95                         goto err;
  96
  97                 led_dat->cdev.name = cur_led->name;
  98                 led_dat->cdev.default_trigger = cur_led->default_trigger;
  99                 led_dat->gpio = cur_led->gpio;
 100                 led_dat->can_sleep = gpio_cansleep(cur_led->gpio);
 101                 led_dat->active_low = cur_led->active_low;
 102                 if (pdata->gpio_blink_set) {
 103                         led_dat->platform_gpio_blink_set = pdata->gpio_blink_set;
 104                         led_dat->cdev.blink_set = gpio_blink_set;
 105                 }
 106                 led_dat->cdev.brightness_set = gpio_led_set;
 107                 led_dat->cdev.brightness = LED_OFF;
 108                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 109
 110                 gpio_direction_output(led_dat->gpio, led_dat->active_low);
 111
 112                 INIT_WORK(&led_dat->work, gpio_led_work);
 113
 114                 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
 115                 if (ret < 0) {
 116                         gpio_free(led_dat->gpio);
 117                         goto err;
 118                 }
 119         }
 120
 121         platform_set_drvdata(pdev, leds_data);
 122
 123         return 0;
 124
 125 err:
 126         if (i > 0) {
 127                 for (i = i - 1; i >= 0; i--) {
 128                         led_classdev_unregister(&leds_data[i].cdev);
 129                         cancel_work_sync(&leds_data[i].work);
 130                         gpio_free(leds_data[i].gpio);
 131                 }
 132         }
 133
 134         kfree(leds_data);
 135
 136         return ret;
 137 }
 138
 139 static int __devexit gpio_led_remove(struct platform_device *pdev)
 140 {
 141         int i;
 142         struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
 143         struct gpio_led_data *leds_data;
 144
 145         leds_data = platform_get_drvdata(pdev);
 146
 147         for (i = 0; i < pdata->num_leds; i++) {
 148                 led_classdev_unregister(&leds_data[i].cdev);
 149                 cancel_work_sync(&leds_data[i].work);
 150                 gpio_free(leds_data[i].gpio);
 151         }
 152
 153         kfree(leds_data);
 154
 155         return 0;
 156 }
 157
 158 static struct platform_driver gpio_led_driver = {
 159         .probe          = gpio_led_probe,
 160         .remove         = __devexit_p(gpio_led_remove),
 161         .driver         = {
 162                 .name   = "leds-gpio",
 163                 .owner  = THIS_MODULE,
 164         },
 165 };
 166
 167 static int __init gpio_led_init(void)
 168 {
 169         return platform_driver_register(&gpio_led_driver);
 170 }
 171
 172 static void __exit gpio_led_exit(void)
 173 {
 174         platform_driver_unregister(&gpio_led_driver);
 175 }
 176
 177 module_init(gpio_led_init);
 178 module_exit(gpio_led_exit);
 179
 180 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>");
 181 MODULE_DESCRIPTION("GPIO LED driver");
 182 MODULE_LICENSE("GPL");
 183 MODULE_ALIAS("platform:leds-gpio");