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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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