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  * Copyright (C) 2008 Freescale Semiconductor, Inc.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/leds.h>
  17 #include <linux/of_platform.h>
  18 #include <linux/of_gpio.h>
  19 #include <linux/slab.h>
  20 #include <linux/workqueue.h>
  21
  22 #include <asm/gpio.h>
  23
  24 struct gpio_led_data {
  25         struct led_classdev cdev;
  26         unsigned gpio;
  27         struct work_struct work;
  28         u8 new_level;
  29         u8 can_sleep;
  30         u8 active_low;
  31         u8 blinking;
  32         int (*platform_gpio_blink_set)(unsigned gpio, int state,
  33                         unsigned long *delay_on, unsigned long *delay_off);
  34 };
  35
  36 static void gpio_led_work(struct work_struct *work)
  37 {
  38         struct gpio_led_data    *led_dat =
  39                 container_of(work, struct gpio_led_data, work);
  40
  41         if (led_dat->blinking) {
  42                 led_dat->platform_gpio_blink_set(led_dat->gpio,
  43                                                  led_dat->new_level,
  44                                                  NULL, NULL);
  45                 led_dat->blinking = 0;
  46         } else
  47                 gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
  48 }
  49
  50 static void gpio_led_set(struct led_classdev *led_cdev,
  51         enum led_brightness value)
  52 {
  53         struct gpio_led_data *led_dat =
  54                 container_of(led_cdev, struct gpio_led_data, cdev);
  55         int level;
  56
  57         if (value == LED_OFF)
  58                 level = 0;
  59         else
  60                 level = 1;
  61
  62         if (led_dat->active_low)
  63                 level = !level;
  64
  65         /* Setting GPIOs with I2C/etc requires a task context, and we don't
  66          * seem to have a reliable way to know if we're already in one; so
  67          * let's just assume the worst.
  68          */
  69         if (led_dat->can_sleep) {
  70                 led_dat->new_level = level;
  71                 schedule_work(&led_dat->work);
  72         } else {
  73                 if (led_dat->blinking) {
  74                         led_dat->platform_gpio_blink_set(led_dat->gpio, level,
  75                                                          NULL, NULL);
  76                         led_dat->blinking = 0;
  77                 } else
  78                         gpio_set_value(led_dat->gpio, level);
  79         }
  80 }
  81
  82 static int gpio_blink_set(struct led_classdev *led_cdev,
  83         unsigned long *delay_on, unsigned long *delay_off)
  84 {
  85         struct gpio_led_data *led_dat =
  86                 container_of(led_cdev, struct gpio_led_data, cdev);
  87
  88         led_dat->blinking = 1;
  89         return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK,
  90                                                 delay_on, delay_off);
  91 }
  92
  93 static int __devinit create_gpio_led(const struct gpio_led *template,
  94         struct gpio_led_data *led_dat, struct device *parent,
  95         int (*blink_set)(unsigned, int, unsigned long *, unsigned long *))
  96 {
  97         int ret, state;
  98
  99         led_dat->gpio = -1;
 100
 101         /* skip leds that aren't available */
 102         if (!gpio_is_valid(template->gpio)) {
 103                 printk(KERN_INFO "Skipping unavailable LED gpio %d (%s)\n",
 104                                 template->gpio, template->name);
 105                 return 0;
 106         }
 107
 108         ret = gpio_request(template->gpio, template->name);
 109         if (ret < 0)
 110                 return ret;
 111
 112         led_dat->cdev.name = template->name;
 113         led_dat->cdev.default_trigger = template->default_trigger;
 114         led_dat->gpio = template->gpio;
 115         led_dat->can_sleep = gpio_cansleep(template->gpio);
 116         led_dat->active_low = template->active_low;
 117         led_dat->blinking = 0;
 118         if (blink_set) {
 119                 led_dat->platform_gpio_blink_set = blink_set;
 120                 led_dat->cdev.blink_set = gpio_blink_set;
 121         }
 122         led_dat->cdev.brightness_set = gpio_led_set;
 123         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 124                 state = !!gpio_get_value(led_dat->gpio) ^ led_dat->active_low;
 125         else
 126                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 127         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 128         if (!template->retain_state_suspended)
 129                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 130
 131         ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);
 132         if (ret < 0)
 133                 goto err;
 134
 135         INIT_WORK(&led_dat->work, gpio_led_work);
 136
 137         ret = led_classdev_register(parent, &led_dat->cdev);
 138         if (ret < 0)
 139                 goto err;
 140
 141         return 0;
 142 err:
 143         gpio_free(led_dat->gpio);
 144         return ret;
 145 }
 146
 147 static void delete_gpio_led(struct gpio_led_data *led)
 148 {
 149         if (!gpio_is_valid(led->gpio))
 150                 return;
 151         led_classdev_unregister(&led->cdev);
 152         cancel_work_sync(&led->work);
 153         gpio_free(led->gpio);
 154 }
 155
 156 struct gpio_leds_priv {
 157         int num_leds;
 158         struct gpio_led_data leds[];
 159 };
 160
 161 static inline int sizeof_gpio_leds_priv(int num_leds)
 162 {
 163         return sizeof(struct gpio_leds_priv) +
 164                 (sizeof(struct gpio_led_data) * num_leds);
 165 }
 166
 167 /* Code to create from OpenFirmware platform devices */
 168 #ifdef CONFIG_LEDS_GPIO_OF
 169 static struct gpio_leds_priv * __devinit gpio_leds_create_of(struct platform_device *pdev)
 170 {
 171         struct device_node *np = pdev->dev.of_node, *child;
 172         struct gpio_leds_priv *priv;
 173         int count = 0, ret;
 174
 175         /* count LEDs in this device, so we know how much to allocate */
 176         for_each_child_of_node(np, child)
 177                 count++;
 178         if (!count)
 179                 return NULL;
 180
 181         priv = kzalloc(sizeof_gpio_leds_priv(count), GFP_KERNEL);
 182         if (!priv)
 183                 return NULL;
 184
 185         for_each_child_of_node(np, child) {
 186                 struct gpio_led led = {};
 187                 enum of_gpio_flags flags;
 188                 const char *state;
 189
 190                 led.gpio = of_get_gpio_flags(child, 0, &flags);
 191                 led.active_low = flags & OF_GPIO_ACTIVE_LOW;
 192                 led.name = of_get_property(child, "label", NULL) ? : child->name;
 193                 led.default_trigger =
 194                         of_get_property(child, "linux,default-trigger", NULL);
 195                 state = of_get_property(child, "default-state", NULL);
 196                 if (state) {
 197                         if (!strcmp(state, "keep"))
 198                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 199                         else if (!strcmp(state, "on"))
 200                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 201                         else
 202                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 203                 }
 204
 205                 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
 206                                       &pdev->dev, NULL);
 207                 if (ret < 0) {
 208                         of_node_put(child);
 209                         goto err;
 210                 }
 211         }
 212
 213         return priv;
 214
 215 err:
 216         for (count = priv->num_leds - 2; count >= 0; count--)
 217                 delete_gpio_led(&priv->leds[count]);
 218         kfree(priv);
 219         return NULL;
 220 }
 221
 222 static const struct of_device_id of_gpio_leds_match[] = {
 223         { .compatible = "gpio-leds", },
 224         {},
 225 };
 226 #else
 227 static struct gpio_leds_priv * __devinit gpio_leds_create_of(struct platform_device *pdev)
 228 {
 229         return NULL;
 230 }
 231 #define of_gpio_leds_match NULL
 232 #endif
 233
 234
 235 static int __devinit gpio_led_probe(struct platform_device *pdev)
 236 {
 237         struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
 238         struct gpio_leds_priv *priv;
 239         int i, ret = 0;
 240
 241         if (pdata && pdata->num_leds) {
 242                 priv = kzalloc(sizeof_gpio_leds_priv(pdata->num_leds),
 243                                 GFP_KERNEL);
 244                 if (!priv)
 245                         return -ENOMEM;
 246
 247                 priv->num_leds = pdata->num_leds;
 248                 for (i = 0; i < priv->num_leds; i++) {
 249                         ret = create_gpio_led(&pdata->leds[i],
 250                                               &priv->leds[i],
 251                                               &pdev->dev, pdata->gpio_blink_set);
 252                         if (ret < 0) {
 253                                 /* On failure: unwind the led creations */
 254                                 for (i = i - 1; i >= 0; i--)
 255                                         delete_gpio_led(&priv->leds[i]);
 256                                 kfree(priv);
 257                                 return ret;
 258                         }
 259                 }
 260         } else {
 261                 priv = gpio_leds_create_of(pdev);
 262                 if (!priv)
 263                         return -ENODEV;
 264         }
 265
 266         platform_set_drvdata(pdev, priv);
 267
 268         return 0;
 269 }
 270
 271 static int __devexit gpio_led_remove(struct platform_device *pdev)
 272 {
 273         struct gpio_leds_priv *priv = dev_get_drvdata(&pdev->dev);
 274         int i;
 275
 276         for (i = 0; i < priv->num_leds; i++)
 277                 delete_gpio_led(&priv->leds[i]);
 278
 279         dev_set_drvdata(&pdev->dev, NULL);
 280         kfree(priv);
 281
 282         return 0;
 283 }
 284
 285 static struct platform_driver gpio_led_driver = {
 286         .probe          = gpio_led_probe,
 287         .remove         = __devexit_p(gpio_led_remove),
 288         .driver         = {
 289                 .name   = "leds-gpio",
 290                 .owner  = THIS_MODULE,
 291                 .of_match_table = of_gpio_leds_match,
 292         },
 293 };
 294
 295 MODULE_ALIAS("platform:leds-gpio");
 296
 297 static int __init gpio_led_init(void)
 298 {
 299         return platform_driver_register(&gpio_led_driver);
 300 }
 301
 302 static void __exit gpio_led_exit(void)
 303 {
 304         platform_driver_unregister(&gpio_led_driver);
 305 }
 306
 307 module_init(gpio_led_init);
 308 module_exit(gpio_led_exit);
 309
 310 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 311 MODULE_DESCRIPTION("GPIO LED driver");
 312 MODULE_LICENSE("GPL");