88pm860x_bl.c

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/*
 * Backlight driver for Marvell Semiconductor 88PM8606
 *
 * Copyright (C) 2009 Marvell International Ltd.
 *  Haojian Zhuang <[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/init.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/fb.h>
#include <linux/i2c.h>
#include <linux/backlight.h>
#include <linux/mfd/88pm860x.h>
#include <linux/module.h>

#define MAX_BRIGHTNESS      (0xFF)
#define MIN_BRIGHTNESS      (0)

#define CURRENT_BITMASK     (0x1F << 1)

struct pm860x_backlight_data {
    struct pm860x_chip *chip;
    struct i2c_client *i2c;
    int current_brightness;
    int port;
    int pwm;
    int iset;
    int reg_duty_cycle;
    int reg_always_on;
    int reg_current;
};

static int backlight_power_set(struct pm860x_chip *chip, int port,
        int on)
{
    int ret = -EINVAL;

    switch (port) {
    case 0:
        ret = on ? pm8606_osc_enable(chip, WLED1_DUTY) :
            pm8606_osc_disable(chip, WLED1_DUTY);
        break;
    case 1:
        ret = on ? pm8606_osc_enable(chip, WLED2_DUTY) :
            pm8606_osc_disable(chip, WLED2_DUTY);
        break;
    case 2:
        ret = on ? pm8606_osc_enable(chip, WLED3_DUTY) :
            pm8606_osc_disable(chip, WLED3_DUTY);
        break;
    }
    return ret;
}

static int pm860x_backlight_set(struct backlight_device *bl, int brightness)
{
    struct pm860x_backlight_data *data = bl_get_data(bl);
    struct pm860x_chip *chip = data->chip;
    unsigned char value;
    int ret;

    if (brightness > MAX_BRIGHTNESS)
        value = MAX_BRIGHTNESS;
    else
        value = brightness;

    if (brightness)
        backlight_power_set(chip, data->port, 1);

    ret = pm860x_reg_write(data->i2c, data->reg_duty_cycle, value);
    if (ret < 0)
        goto out;

    if ((data->current_brightness == 0) && brightness) {
        if (data->iset) {
            ret = pm860x_set_bits(data->i2c, data->reg_current,
                          CURRENT_BITMASK, data->iset);
            if (ret < 0)
                goto out;
        }
        if (data->pwm) {
            ret = pm860x_set_bits(data->i2c, PM8606_PWM,
                          PM8606_PWM_FREQ_MASK, data->pwm);
            if (ret < 0)
                goto out;
        }
        if (brightness == MAX_BRIGHTNESS) {
            /* set WLED_ON bit as 100% */
            ret = pm860x_set_bits(data->i2c, data->reg_always_on,
                          PM8606_WLED_ON, PM8606_WLED_ON);
        }
    } else {
        if (brightness == MAX_BRIGHTNESS) {
            /* set WLED_ON bit as 100% */
            ret = pm860x_set_bits(data->i2c, data->reg_always_on,
                          PM8606_WLED_ON, PM8606_WLED_ON);
        } else {
            /* clear WLED_ON bit since it's not 100% */
            ret = pm860x_set_bits(data->i2c, data->reg_always_on,
                          PM8606_WLED_ON, 0);
        }
    }
    if (ret < 0)
        goto out;

    if (brightness == 0)
        backlight_power_set(chip, data->port, 0);

    dev_dbg(chip->dev, "set brightness %d\n", value);
    data->current_brightness = value;
    return 0;
out:
    dev_dbg(chip->dev, "set brightness %d failure with return "
        "value:%d\n", value, ret);
    return ret;
}

static int pm860x_backlight_update_status(struct backlight_device *bl)
{
    int brightness = bl->props.brightness;

    if (bl->props.power != FB_BLANK_UNBLANK)
        brightness = 0;

    if (bl->props.fb_blank != FB_BLANK_UNBLANK)
        brightness = 0;

    if (bl->props.state & BL_CORE_SUSPENDED)
        brightness = 0;

    return pm860x_backlight_set(bl, brightness);
}

static int pm860x_backlight_get_brightness(struct backlight_device *bl)
{
    struct pm860x_backlight_data *data = bl_get_data(bl);
    struct pm860x_chip *chip = data->chip;
    int ret;

    ret = pm860x_reg_read(data->i2c, data->reg_duty_cycle);
    if (ret < 0)
        goto out;
    data->current_brightness = ret;
    dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
    return data->current_brightness;
out:
    return -EINVAL;
}

static const struct backlight_ops pm860x_backlight_ops = {
    .options    = BL_CORE_SUSPENDRESUME,
    .update_status  = pm860x_backlight_update_status,
    .get_brightness = pm860x_backlight_get_brightness,
};

#ifdef CONFIG_OF
static int pm860x_backlight_dt_init(struct platform_device *pdev,
                    struct pm860x_backlight_data *data,
                    char *name)
{
    struct device_node *nproot = pdev->dev.parent->of_node, *np;
    int iset = 0;
    if (!nproot)
        return -ENODEV;
    nproot = of_find_node_by_name(nproot, "backlights");
    if (!nproot) {
        dev_err(&pdev->dev, "failed to find backlights node\n");
        return -ENODEV;
    }
    for_each_child_of_node(nproot, np) {
        if (!of_node_cmp(np->name, name)) {
            of_property_read_u32(np, "marvell,88pm860x-iset",
                         &iset);
            data->iset = PM8606_WLED_CURRENT(iset);
            of_property_read_u32(np, "marvell,88pm860x-pwm",
                         &data->pwm);
            break;
        }
    }
    return 0;
}
#else
#define pm860x_backlight_dt_init(x, y, z)   (-1)
#endif

static int pm860x_backlight_probe(struct platform_device *pdev)
{
    struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
    struct pm860x_backlight_pdata *pdata = pdev->dev.platform_data;
    struct pm860x_backlight_data *data;
    struct backlight_device *bl;
    struct resource *res;
    struct backlight_properties props;
    char name[MFD_NAME_SIZE];
    int ret = 0;

    data = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_backlight_data),
                GFP_KERNEL);
    if (data == NULL)
        return -ENOMEM;
    res = platform_get_resource_byname(pdev, IORESOURCE_REG, "duty cycle");
    if (!res) {
        dev_err(&pdev->dev, "No REG resource for duty cycle\n");
        ret = -ENXIO;
        goto out;
    }
    data->reg_duty_cycle = res->start;
    res = platform_get_resource_byname(pdev, IORESOURCE_REG, "always on");
    if (!res) {
        dev_err(&pdev->dev, "No REG resorce for always on\n");
        ret = -ENXIO;
        goto out;
    }
    data->reg_always_on = res->start;
    res = platform_get_resource_byname(pdev, IORESOURCE_REG, "current");
    if (!res) {
        dev_err(&pdev->dev, "No REG resource for current\n");
        ret = -ENXIO;
        goto out;
    }
    data->reg_current = res->start;

    memset(name, 0, MFD_NAME_SIZE);
    sprintf(name, "backlight-%d", pdev->id);
    data->port = pdev->id;
    data->chip = chip;
    data->i2c = (chip->id == CHIP_PM8606) ? chip->client    \
            : chip->companion;
    data->current_brightness = MAX_BRIGHTNESS;
    if (pm860x_backlight_dt_init(pdev, data, name)) {
        if (pdata) {
            data->pwm = pdata->pwm;
            data->iset = pdata->iset;
        }
    }

    memset(&props, 0, sizeof(struct backlight_properties));
    props.type = BACKLIGHT_RAW;
    props.max_brightness = MAX_BRIGHTNESS;
    bl = backlight_device_register(name, &pdev->dev, data,
                    &pm860x_backlight_ops, &props);
    if (IS_ERR(bl)) {
        dev_err(&pdev->dev, "failed to register backlight\n");
        return PTR_ERR(bl);
    }
    bl->props.brightness = MAX_BRIGHTNESS;

    platform_set_drvdata(pdev, bl);

    /* read current backlight */
    ret = pm860x_backlight_get_brightness(bl);
    if (ret < 0)
        goto out_brt;

    backlight_update_status(bl);
    return 0;
out_brt:
    backlight_device_unregister(bl);
out:
    devm_kfree(&pdev->dev, data);
    return ret;
}

static int pm860x_backlight_remove(struct platform_device *pdev)
{
    struct backlight_device *bl = platform_get_drvdata(pdev);

    backlight_device_unregister(bl);
    return 0;
}

static struct platform_driver pm860x_backlight_driver = {
    .driver     = {
        .name   = "88pm860x-backlight",
        .owner  = THIS_MODULE,
    },
    .probe      = pm860x_backlight_probe,
    .remove     = pm860x_backlight_remove,
};

module_platform_driver(pm860x_backlight_driver);

MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606");
MODULE_AUTHOR("Haojian Zhuang <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:88pm860x-backlight");