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