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Subject[PATCH v2] leds: Add LED class driver for regulator driven LEDs.
Date
This driver provides an interface for controlling LEDs (or vibrators)
connected to PMICs for which there is a regulator framework driver.

This driver can be used, for instance, to control vibrator on all Motorola EZX
phones using the pcap-regulator driver services.

Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
---
Addressed the observations from Mark Brown, Liam Girdwood and Linus Walleij.

Patch against:
git://git.o-hand.com/linux-rpurdie-leds for-mm

Changes since v1:
- Use "vled" as supply id.
- use regulator_get_exclusive
- remove double semicolon
- check for LED_OFF instead of 0
- handle regulators which can't change voltages
- rename led_regulator_get_vdd to led_regulator_get_voltage
- split regulator_led_set_value out of led_work
- allow setting an initial brightness value
- fix sections markers (__devinit, __devexit, etc.)

The only slight doubt I still have is about
led_regulator_get_max_brightness(), I have to use regulator_set_voltage() there
to tell if a regulator has REGULATOR_CHANGE_VOLTAGE enabled.

Regards,
Antonio

drivers/leds/Kconfig | 6 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-regulator.c | 242 ++++++++++++++++++++++++++++++++++++++++
include/linux/leds-regulator.h | 46 ++++++++
4 files changed, 295 insertions(+), 0 deletions(-)
create mode 100644 drivers/leds/leds-regulator.c
create mode 100644 include/linux/leds-regulator.h
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index f12a996..8a0e1ec 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -229,6 +229,12 @@ config LEDS_PWM
help
This option enables support for pwm driven LEDs

+config LEDS_REGULATOR
+ tristate "REGULATOR driven LED support"
+ depends on LEDS_CLASS && REGULATOR
+ help
+ This option enables support for regulator driven LEDs.
+
config LEDS_BD2802
tristate "LED driver for BD2802 RGB LED"
depends on LEDS_CLASS && I2C
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 176f0c6..9e63869 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_LEDS_DA903X) += leds-da903x.o
obj-$(CONFIG_LEDS_WM831X_STATUS) += leds-wm831x-status.o
obj-$(CONFIG_LEDS_WM8350) += leds-wm8350.o
obj-$(CONFIG_LEDS_PWM) += leds-pwm.o
+obj-$(CONFIG_LEDS_REGULATOR) += leds-regulator.o
obj-$(CONFIG_LEDS_INTEL_SS4200) += leds-ss4200.o
obj-$(CONFIG_LEDS_LT3593) += leds-lt3593.o
obj-$(CONFIG_LEDS_ADP5520) += leds-adp5520.o
diff --git a/drivers/leds/leds-regulator.c b/drivers/leds/leds-regulator.c
new file mode 100644
index 0000000..7f00de3
--- /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(&regulator_led_driver);
+}
+module_init(regulator_led_init);
+
+static void __exit regulator_led_exit(void)
+{
+ platform_driver_unregister(&regulator_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");
diff --git a/include/linux/leds-regulator.h b/include/linux/leds-regulator.h
new file mode 100644
index 0000000..a40275a
--- /dev/null
+++ b/include/linux/leds-regulator.h
@@ -0,0 +1,46 @@
+/*
+ * leds-regulator.h - platform data structure for regulator driven LEDs.
+ *
+ * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it>
+ *
+ * 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.
+ *
+ */
+
+#ifndef __LINUX_LEDS_REGULATOR_H
+#define __LINUX_LEDS_REGULATOR_H
+
+/*
+ * Use "vled" as supply id when declaring the regulator consumer:
+ *
+ * static struct regulator_consumer_supply pcap_regulator_VVIB_consumers [] = {
+ * { .dev_name = "leds-regulator.0", supply = "vled" },
+ * };
+ *
+ * If you have several regulator driven LEDs, you can append a numerical id to
+ * .dev_name as done above, and use the same id when declaring the platform
+ * device:
+ *
+ * static struct led_regulator_platform_data a780_vibrator_data = {
+ * .name = "a780::vibrator",
+ * };
+ *
+ * static struct platform_device a780_vibrator = {
+ * .name = "leds-regulator",
+ * .id = 0,
+ * .dev = {
+ * .platform_data = &a780_vibrator_data,
+ * },
+ * };
+ */
+
+#include <linux/leds.h>
+
+struct led_regulator_platform_data {
+ char *name; /* LED name as expected by LED class */
+ enum led_brightness brightness; /* initial brightness value */
+};
+
+#endif /* __LINUX_LEDS_REGULATOR_H */
--
1.6.5.4


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