leds-wm8350.c

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/*
 * LED driver for WM8350 driven LEDS.
 *
 * Copyright(C) 2007, 2008 Wolfson Microelectronics PLC.
 *
 * 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/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/leds.h>
#include <linux/err.h>
#include <linux/mfd/wm8350/pmic.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/module.h>

/* Microamps */
static const int isink_cur[] = {
    4,
    5,
    6,
    7,
    8,
    10,
    11,
    14,
    16,
    19,
    23,
    27,
    32,
    39,
    46,
    54,
    65,
    77,
    92,
    109,
    130,
    154,
    183,
    218,
    259,
    308,
    367,
    436,
    518,
    616,
    733,
    872,
    1037,
    1233,
    1466,
    1744,
    2073,
    2466,
    2933,
    3487,
    4147,
    4932,
    5865,
    6975,
    8294,
    9864,
    11730,
    13949,
    16589,
    19728,
    23460,
    27899,
    33178,
    39455,
    46920,
    55798,
    66355,
    78910,
    93840,
    111596,
    132710,
    157820,
    187681,
    223191
};

#define to_wm8350_led(led_cdev) \
    container_of(led_cdev, struct wm8350_led, cdev)

static void wm8350_led_enable(struct wm8350_led *led)
{
    int ret;

    if (led->enabled)
        return;

    ret = regulator_enable(led->isink);
    if (ret != 0) {
        dev_err(led->cdev.dev, "Failed to enable ISINK: %d\n", ret);
        return;
    }

    ret = regulator_enable(led->dcdc);
    if (ret != 0) {
        dev_err(led->cdev.dev, "Failed to enable DCDC: %d\n", ret);
        regulator_disable(led->isink);
        return;
    }

    led->enabled = 1;
}

static void wm8350_led_disable(struct wm8350_led *led)
{
    int ret;

    if (!led->enabled)
        return;

    ret = regulator_disable(led->dcdc);
    if (ret != 0) {
        dev_err(led->cdev.dev, "Failed to disable DCDC: %d\n", ret);
        return;
    }

    ret = regulator_disable(led->isink);
    if (ret != 0) {
        dev_err(led->cdev.dev, "Failed to disable ISINK: %d\n", ret);
        regulator_enable(led->dcdc);
        return;
    }

    led->enabled = 0;
}

static void led_work(struct work_struct *work)
{
    struct wm8350_led *led = container_of(work, struct wm8350_led, work);
    int ret;
    int uA;
    unsigned long flags;

    mutex_lock(&led->mutex);

    spin_lock_irqsave(&led->value_lock, flags);

    if (led->value == LED_OFF) {
        spin_unlock_irqrestore(&led->value_lock, flags);
        wm8350_led_disable(led);
        goto out;
    }

    /* This scales linearly into the index of valid current
     * settings which results in a linear scaling of perceived
     * brightness due to the non-linear current settings provided
     * by the hardware.
     */
    uA = (led->max_uA_index * led->value) / LED_FULL;
    spin_unlock_irqrestore(&led->value_lock, flags);
    BUG_ON(uA >= ARRAY_SIZE(isink_cur));

    ret = regulator_set_current_limit(led->isink, isink_cur[uA],
                      isink_cur[uA]);
    if (ret != 0)
        dev_err(led->cdev.dev, "Failed to set %duA: %d\n",
            isink_cur[uA], ret);

    wm8350_led_enable(led);

out:
    mutex_unlock(&led->mutex);
}

static void wm8350_led_set(struct led_classdev *led_cdev,
               enum led_brightness value)
{
    struct wm8350_led *led = to_wm8350_led(led_cdev);
    unsigned long flags;

    spin_lock_irqsave(&led->value_lock, flags);
    led->value = value;
    schedule_work(&led->work);
    spin_unlock_irqrestore(&led->value_lock, flags);
}

static void wm8350_led_shutdown(struct platform_device *pdev)
{
    struct wm8350_led *led = platform_get_drvdata(pdev);

    mutex_lock(&led->mutex);
    led->value = LED_OFF;
    wm8350_led_disable(led);
    mutex_unlock(&led->mutex);
}

static int wm8350_led_probe(struct platform_device *pdev)
{
    struct regulator *isink, *dcdc;
    struct wm8350_led *led;
    struct wm8350_led_platform_data *pdata = pdev->dev.platform_data;
    int i;

    if (pdata == NULL) {
        dev_err(&pdev->dev, "no platform data\n");
        return -ENODEV;
    }

    if (pdata->max_uA < isink_cur[0]) {
        dev_err(&pdev->dev, "Invalid maximum current %duA\n",
            pdata->max_uA);
        return -EINVAL;
    }

    isink = devm_regulator_get(&pdev->dev, "led_isink");
    if (IS_ERR(isink)) {
        printk(KERN_ERR "%s: can't get ISINK\n", __func__);
        return PTR_ERR(isink);
    }

    dcdc = devm_regulator_get(&pdev->dev, "led_vcc");
    if (IS_ERR(dcdc)) {
        printk(KERN_ERR "%s: can't get DCDC\n", __func__);
        return PTR_ERR(dcdc);
    }

    led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
    if (led == NULL)
        return -ENOMEM;

    led->cdev.brightness_set = wm8350_led_set;
    led->cdev.default_trigger = pdata->default_trigger;
    led->cdev.name = pdata->name;
    led->cdev.flags |= LED_CORE_SUSPENDRESUME;
    led->enabled = regulator_is_enabled(isink);
    led->isink = isink;
    led->dcdc = dcdc;

    for (i = 0; i < ARRAY_SIZE(isink_cur) - 1; i++)
        if (isink_cur[i] >= pdata->max_uA)
            break;
    led->max_uA_index = i;
    if (pdata->max_uA != isink_cur[i])
        dev_warn(&pdev->dev,
             "Maximum current %duA is not directly supported,"
             " check platform data\n",
             pdata->max_uA);

    spin_lock_init(&led->value_lock);
    mutex_init(&led->mutex);
    INIT_WORK(&led->work, led_work);
    led->value = LED_OFF;
    platform_set_drvdata(pdev, led);

    return led_classdev_register(&pdev->dev, &led->cdev);
}

static int wm8350_led_remove(struct platform_device *pdev)
{
    struct wm8350_led *led = platform_get_drvdata(pdev);

    led_classdev_unregister(&led->cdev);
    flush_work(&led->work);
    wm8350_led_disable(led);
    return 0;
}

static struct platform_driver wm8350_led_driver = {
    .driver = {
           .name = "wm8350-led",
           .owner = THIS_MODULE,
           },
    .probe = wm8350_led_probe,
    .remove = wm8350_led_remove,
    .shutdown = wm8350_led_shutdown,
};

module_platform_driver(wm8350_led_driver);

MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM8350 LED driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm8350-led");