diff options
Diffstat (limited to 'drivers/leds/leds-regulator.c')
| -rw-r--r-- | drivers/leds/leds-regulator.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/drivers/leds/leds-regulator.c b/drivers/leds/leds-regulator.c new file mode 100644 index 00000000000..7f00de3ef92 --- /dev/null +++ b/drivers/leds/leds-regulator.c @@ -0,0 +1,242 @@ +/* + * leds-regulator.c - LED class driver for regulator driven LEDs. + * + * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it> + * + * Inspired by leds-wm8350 driver. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <linux/module.h> +#include <linux/err.h> +#include <linux/workqueue.h> +#include <linux/leds.h> +#include <linux/leds-regulator.h> +#include <linux/platform_device.h> +#include <linux/regulator/consumer.h> + +#define to_regulator_led(led_cdev) \ + container_of(led_cdev, struct regulator_led, cdev) + +struct regulator_led { + struct led_classdev cdev; + enum led_brightness value; + int enabled; + struct mutex mutex; + struct work_struct work; + + struct regulator *vcc; +}; + +static inline int led_regulator_get_max_brightness(struct regulator *supply) +{ + int ret; + int voltage = regulator_list_voltage(supply, 0); + + if (voltage <= 0) + return 1; + + /* even if regulator can't change voltages, + * we still assume it can change status + * and the LED can be turned on and off. + */ + ret = regulator_set_voltage(supply, voltage, voltage); + if (ret < 0) + return 1; + + return regulator_count_voltages(supply); +} + +static int led_regulator_get_voltage(struct regulator *supply, + enum led_brightness brightness) +{ + if (brightness == 0) + return -EINVAL; + + return regulator_list_voltage(supply, brightness - 1); +} + + +static void regulator_led_enable(struct regulator_led *led) +{ + int ret; + + if (led->enabled) + return; + + ret = regulator_enable(led->vcc); + if (ret != 0) { + dev_err(led->cdev.dev, "Failed to enable vcc: %d\n", ret); + return; + } + + led->enabled = 1; +} + +static void regulator_led_disable(struct regulator_led *led) +{ + int ret; + + if (!led->enabled) + return; + + ret = regulator_disable(led->vcc); + if (ret != 0) { + dev_err(led->cdev.dev, "Failed to disable vcc: %d\n", ret); + return; + } + + led->enabled = 0; +} + +static void regulator_led_set_value(struct regulator_led *led) +{ + int voltage; + int ret; + + mutex_lock(&led->mutex); + + if (led->value == LED_OFF) { + regulator_led_disable(led); + goto out; + } + + if (led->cdev.max_brightness > 1) { + voltage = led_regulator_get_voltage(led->vcc, led->value); + dev_dbg(led->cdev.dev, "brightness: %d voltage: %d\n", + led->value, voltage); + + ret = regulator_set_voltage(led->vcc, voltage, voltage); + if (ret != 0) + dev_err(led->cdev.dev, "Failed to set voltage %d: %d\n", + voltage, ret); + } + + regulator_led_enable(led); + +out: + mutex_unlock(&led->mutex); +} + +static void led_work(struct work_struct *work) +{ + struct regulator_led *led; + + led = container_of(work, struct regulator_led, work); + regulator_led_set_value(led); +} + +static void regulator_led_brightness_set(struct led_classdev *led_cdev, + enum led_brightness value) +{ + struct regulator_led *led = to_regulator_led(led_cdev); + + led->value = value; + schedule_work(&led->work); +} + +static int __devinit regulator_led_probe(struct platform_device *pdev) +{ + struct led_regulator_platform_data *pdata = pdev->dev.platform_data; + struct regulator_led *led; + struct regulator *vcc; + int ret = 0; + + if (pdata == NULL) { + dev_err(&pdev->dev, "no platform data\n"); + return -ENODEV; + } + + vcc = regulator_get_exclusive(&pdev->dev, "vled"); + if (IS_ERR(vcc)) { + dev_err(&pdev->dev, "Cannot get vcc for %s\n", pdata->name); + return PTR_ERR(vcc); + } + + led = kzalloc(sizeof(*led), GFP_KERNEL); + if (led == NULL) { + ret = -ENOMEM; + goto err_vcc; + } + + led->cdev.max_brightness = led_regulator_get_max_brightness(vcc); + if (pdata->brightness > led->cdev.max_brightness) { + dev_err(&pdev->dev, "Invalid default brightness %d\n", + pdata->brightness); + ret = -EINVAL; + goto err_led; + } + led->value = pdata->brightness; + + led->cdev.brightness_set = regulator_led_brightness_set; + led->cdev.name = pdata->name; + led->cdev.flags |= LED_CORE_SUSPENDRESUME; + led->vcc = vcc; + + mutex_init(&led->mutex); + INIT_WORK(&led->work, led_work); + + platform_set_drvdata(pdev, led); + + ret = led_classdev_register(&pdev->dev, &led->cdev); + if (ret < 0) { + cancel_work_sync(&led->work); + goto err_led; + } + + /* to expose the default value to userspace */ + led->cdev.brightness = led->value; + + /* Set the default led status */ + regulator_led_set_value(led); + + return 0; + +err_led: + kfree(led); +err_vcc: + regulator_put(vcc); + return ret; +} + +static int __devexit regulator_led_remove(struct platform_device *pdev) +{ + struct regulator_led *led = platform_get_drvdata(pdev); + + led_classdev_unregister(&led->cdev); + cancel_work_sync(&led->work); + regulator_led_disable(led); + regulator_put(led->vcc); + kfree(led); + return 0; +} + +static struct platform_driver regulator_led_driver = { + .driver = { + .name = "leds-regulator", + .owner = THIS_MODULE, + }, + .probe = regulator_led_probe, + .remove = __devexit_p(regulator_led_remove), +}; + +static int __init regulator_led_init(void) +{ + return platform_driver_register(®ulator_led_driver); +} +module_init(regulator_led_init); + +static void __exit regulator_led_exit(void) +{ + platform_driver_unregister(®ulator_led_driver); +} +module_exit(regulator_led_exit); + +MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>"); +MODULE_DESCRIPTION("Regulator driven LED driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:leds-regulator"); |