leds-lp8788.c

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/*
 * TI LP8788 MFD - keyled driver
 *
 * Copyright 2012 Texas Instruments
 *
 * Author: Milo(Woogyom) Kim <[email protected]>
 *
 * 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/slab.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/leds.h>
#include <linux/mutex.h>
#include <linux/mfd/lp8788.h>
#include <linux/mfd/lp8788-isink.h>

#define MAX_BRIGHTNESS          LP8788_ISINK_MAX_PWM
#define DEFAULT_LED_NAME        "keyboard-backlight"

struct lp8788_led {
    struct lp8788 *lp;
    struct mutex lock;
    struct work_struct work;
    struct led_classdev led_dev;
    enum lp8788_isink_number isink_num;
    enum led_brightness brightness;
    int on;
};

struct lp8788_led_config {
    enum lp8788_isink_scale scale;
    enum lp8788_isink_number num;
    int iout;
};

static struct lp8788_led_config default_led_config = {
    .scale = LP8788_ISINK_SCALE_100mA,
    .num   = LP8788_ISINK_3,
    .iout  = 0,
};

static int lp8788_led_init_device(struct lp8788_led *led,
                struct lp8788_led_platform_data *pdata)
{
    struct lp8788_led_config *cfg = &default_led_config;
    u8 addr, mask, val;
    int ret;

    if (pdata) {
        cfg->scale = pdata->scale;
        cfg->num = pdata->num;
        cfg->iout = pdata->iout_code;
    }

    led->isink_num = cfg->num;

    /* scale configuration */
    addr = LP8788_ISINK_CTRL;
    mask = 1 << (cfg->num + LP8788_ISINK_SCALE_OFFSET);
    val = cfg->scale << (cfg->num + LP8788_ISINK_SCALE_OFFSET);
    ret = lp8788_update_bits(led->lp, addr, mask, val);
    if (ret)
        return ret;

    /* current configuration */
    addr = lp8788_iout_addr[cfg->num];
    mask = lp8788_iout_mask[cfg->num];
    val = cfg->iout;

    return lp8788_update_bits(led->lp, addr, mask, val);
}

static void lp8788_led_enable(struct lp8788_led *led,
            enum lp8788_isink_number num, int on)
{
    u8 mask = 1 << num;
    u8 val = on << num;

    if (lp8788_update_bits(led->lp, LP8788_ISINK_CTRL, mask, val))
        return;

    led->on = on;
}

static void lp8788_led_work(struct work_struct *work)
{
    struct lp8788_led *led = container_of(work, struct lp8788_led, work);
    enum lp8788_isink_number num = led->isink_num;
    int enable;
    u8 val = led->brightness;

    mutex_lock(&led->lock);

    switch (num) {
    case LP8788_ISINK_1:
    case LP8788_ISINK_2:
    case LP8788_ISINK_3:
        lp8788_write_byte(led->lp, lp8788_pwm_addr[num], val);
        break;
    default:
        mutex_unlock(&led->lock);
        return;
    }

    enable = (val > 0) ? 1 : 0;
    if (enable != led->on)
        lp8788_led_enable(led, num, enable);

    mutex_unlock(&led->lock);
}

static void lp8788_brightness_set(struct led_classdev *led_cdev,
                enum led_brightness brt_val)
{
    struct lp8788_led *led =
            container_of(led_cdev, struct lp8788_led, led_dev);

    led->brightness = brt_val;
    schedule_work(&led->work);
}

static __devinit int lp8788_led_probe(struct platform_device *pdev)
{
    struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
    struct lp8788_led_platform_data *led_pdata;
    struct lp8788_led *led;
    int ret;

    led = devm_kzalloc(lp->dev, sizeof(struct lp8788_led), GFP_KERNEL);
    if (!led)
        return -ENOMEM;

    led->lp = lp;
    led->led_dev.max_brightness = MAX_BRIGHTNESS;
    led->led_dev.brightness_set = lp8788_brightness_set;

    led_pdata = lp->pdata ? lp->pdata->led_pdata : NULL;

    if (!led_pdata || !led_pdata->name)
        led->led_dev.name = DEFAULT_LED_NAME;
    else
        led->led_dev.name = led_pdata->name;

    mutex_init(&led->lock);
    INIT_WORK(&led->work, lp8788_led_work);

    platform_set_drvdata(pdev, led);

    ret = lp8788_led_init_device(led, led_pdata);
    if (ret) {
        dev_err(lp->dev, "led init device err: %d\n", ret);
        return ret;
    }

    ret = led_classdev_register(lp->dev, &led->led_dev);
    if (ret) {
        dev_err(lp->dev, "led register err: %d\n", ret);
        return ret;
    }

    return 0;
}

static int __devexit lp8788_led_remove(struct platform_device *pdev)
{
    struct lp8788_led *led = platform_get_drvdata(pdev);

    led_classdev_unregister(&led->led_dev);
    flush_work(&led->work);

    return 0;
}

static struct platform_driver lp8788_led_driver = {
    .probe = lp8788_led_probe,
    .remove = __devexit_p(lp8788_led_remove),
    .driver = {
        .name = LP8788_DEV_KEYLED,
        .owner = THIS_MODULE,
    },
};
module_platform_driver(lp8788_led_driver);

MODULE_DESCRIPTION("Texas Instruments LP8788 Keyboard LED Driver");
MODULE_AUTHOR("Milo Kim");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:lp8788-keyled");