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* LEDs driver for GPIOs
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* Copyright (C) 2007 8D Technologies inc.
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* Raphael Assenat <raph@8d.com>
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* Copyright (C) 2008 Freescale Semiconductor, Inc.
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/leds.h>
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#include <linux/of_platform.h>
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#include <linux/of_gpio.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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#include <linux/module.h>
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struct gpio_led_data {
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struct led_classdev cdev;
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struct work_struct work;
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int (*platform_gpio_blink_set)(unsigned gpio, int state,
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unsigned long *delay_on, unsigned long *delay_off);
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static void gpio_led_work(struct work_struct *work)
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struct gpio_led_data *led_dat =
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container_of(work, struct gpio_led_data, work);
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if (led_dat->blinking) {
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led_dat->platform_gpio_blink_set(led_dat->gpio,
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led_dat->blinking = 0;
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gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
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static void gpio_led_set(struct led_classdev *led_cdev,
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enum led_brightness value)
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struct gpio_led_data *led_dat =
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container_of(led_cdev, struct gpio_led_data, cdev);
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if (led_dat->active_low)
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/* Setting GPIOs with I2C/etc requires a task context, and we don't
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* seem to have a reliable way to know if we're already in one; so
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* let's just assume the worst.
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if (led_dat->can_sleep) {
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led_dat->new_level = level;
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schedule_work(&led_dat->work);
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if (led_dat->blinking) {
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led_dat->platform_gpio_blink_set(led_dat->gpio, level,
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led_dat->blinking = 0;
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gpio_set_value(led_dat->gpio, level);
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static int gpio_blink_set(struct led_classdev *led_cdev,
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unsigned long *delay_on, unsigned long *delay_off)
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struct gpio_led_data *led_dat =
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container_of(led_cdev, struct gpio_led_data, cdev);
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led_dat->blinking = 1;
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return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK,
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static int __devinit create_gpio_led(const struct gpio_led *template,
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struct gpio_led_data *led_dat, struct device *parent,
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int (*blink_set)(unsigned, int, unsigned long *, unsigned long *))
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/* skip leds that aren't available */
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if (!gpio_is_valid(template->gpio)) {
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printk(KERN_INFO "Skipping unavailable LED gpio %d (%s)\n",
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template->gpio, template->name);
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ret = gpio_request(template->gpio, template->name);
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led_dat->cdev.name = template->name;
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led_dat->cdev.default_trigger = template->default_trigger;
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led_dat->gpio = template->gpio;
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led_dat->can_sleep = gpio_cansleep(template->gpio);
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led_dat->active_low = template->active_low;
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led_dat->blinking = 0;
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led_dat->platform_gpio_blink_set = blink_set;
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led_dat->cdev.blink_set = gpio_blink_set;
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led_dat->cdev.brightness_set = gpio_led_set;
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if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
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state = !!gpio_get_value_cansleep(led_dat->gpio) ^ led_dat->active_low;
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state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
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led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
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if (!template->retain_state_suspended)
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led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
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ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);
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INIT_WORK(&led_dat->work, gpio_led_work);
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ret = led_classdev_register(parent, &led_dat->cdev);
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gpio_free(led_dat->gpio);
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static void delete_gpio_led(struct gpio_led_data *led)
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if (!gpio_is_valid(led->gpio))
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led_classdev_unregister(&led->cdev);
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cancel_work_sync(&led->work);
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gpio_free(led->gpio);
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struct gpio_leds_priv {
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struct gpio_led_data leds[];
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static inline int sizeof_gpio_leds_priv(int num_leds)
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return sizeof(struct gpio_leds_priv) +
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(sizeof(struct gpio_led_data) * num_leds);
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/* Code to create from OpenFirmware platform devices */
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#ifdef CONFIG_OF_GPIO
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static struct gpio_leds_priv * __devinit gpio_leds_create_of(struct platform_device *pdev)
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struct device_node *np = pdev->dev.of_node, *child;
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struct gpio_leds_priv *priv;
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/* count LEDs in this device, so we know how much to allocate */
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for_each_child_of_node(np, child)
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priv = kzalloc(sizeof_gpio_leds_priv(count), GFP_KERNEL);
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for_each_child_of_node(np, child) {
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struct gpio_led led = {};
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enum of_gpio_flags flags;
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led.gpio = of_get_gpio_flags(child, 0, &flags);
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led.active_low = flags & OF_GPIO_ACTIVE_LOW;
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led.name = of_get_property(child, "label", NULL) ? : child->name;
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led.default_trigger =
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of_get_property(child, "linux,default-trigger", NULL);
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state = of_get_property(child, "default-state", NULL);
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if (!strcmp(state, "keep"))
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led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
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else if (!strcmp(state, "on"))
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led.default_state = LEDS_GPIO_DEFSTATE_ON;
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led.default_state = LEDS_GPIO_DEFSTATE_OFF;
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ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
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for (count = priv->num_leds - 2; count >= 0; count--)
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delete_gpio_led(&priv->leds[count]);
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static const struct of_device_id of_gpio_leds_match[] = {
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{ .compatible = "gpio-leds", },
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#else /* CONFIG_OF_GPIO */
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static struct gpio_leds_priv * __devinit gpio_leds_create_of(struct platform_device *pdev)
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#define of_gpio_leds_match NULL
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#endif /* CONFIG_OF_GPIO */
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static int __devinit gpio_led_probe(struct platform_device *pdev)
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struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
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struct gpio_leds_priv *priv;
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if (pdata && pdata->num_leds) {
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priv = kzalloc(sizeof_gpio_leds_priv(pdata->num_leds),
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priv->num_leds = pdata->num_leds;
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for (i = 0; i < priv->num_leds; i++) {
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ret = create_gpio_led(&pdata->leds[i],
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&pdev->dev, pdata->gpio_blink_set);
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/* On failure: unwind the led creations */
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for (i = i - 1; i >= 0; i--)
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delete_gpio_led(&priv->leds[i]);
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priv = gpio_leds_create_of(pdev);
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platform_set_drvdata(pdev, priv);
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static int __devexit gpio_led_remove(struct platform_device *pdev)
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struct gpio_leds_priv *priv = dev_get_drvdata(&pdev->dev);
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for (i = 0; i < priv->num_leds; i++)
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delete_gpio_led(&priv->leds[i]);
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dev_set_drvdata(&pdev->dev, NULL);
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static struct platform_driver gpio_led_driver = {
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.probe = gpio_led_probe,
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.remove = __devexit_p(gpio_led_remove),
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.owner = THIS_MODULE,
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.of_match_table = of_gpio_leds_match,
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MODULE_ALIAS("platform:leds-gpio");
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static int __init gpio_led_init(void)
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return platform_driver_register(&gpio_led_driver);
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static void __exit gpio_led_exit(void)
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platform_driver_unregister(&gpio_led_driver);
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module_init(gpio_led_init);
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module_exit(gpio_led_exit);
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MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
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MODULE_DESCRIPTION("GPIO LED driver");
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MODULE_LICENSE("GPL");