--- /dev/null
+/*
+ * 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/slab.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 regulator_led_probe(struct platform_device *pdev)
+{
+ struct led_regulator_platform_data *pdata =
+ dev_get_platdata(&pdev->dev);
+ struct regulator_led *led;
+ struct regulator *vcc;
+ int ret = 0;
+
+ if (pdata == NULL) {
+ dev_err(&pdev->dev, "no platform data\n");
+ return -ENODEV;
+ }
+
+ vcc = devm_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 = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
+ if (led == NULL)
+ return -ENOMEM;
+
+ 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);
+ return -EINVAL;
+ }
+ 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;
+
+ /* to handle correctly an already enabled regulator */
+ if (regulator_is_enabled(led->vcc))
+ led->enabled = 1;
+
+ 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);
+ return ret;
+ }
+
+ /* to expose the default value to userspace */
+ led->cdev.brightness = led->value;
+
+ /* Set the default led status */
+ regulator_led_set_value(led);
+
+ return 0;
+}
+
+static int 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);
+ return 0;
+}
+
+static struct platform_driver regulator_led_driver = {
+ .driver = {
+ .name = "leds-regulator",
+ },
+ .probe = regulator_led_probe,
+ .remove = regulator_led_remove,
+};
+
+module_platform_driver(regulator_led_driver);
+
+MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");
+MODULE_DESCRIPTION("Regulator driven LED driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:leds-regulator");
Code Review / kvmfornfv.git / blobdiff