lm3533_bl.c

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/*
 * lm3533-bl.c -- LM3533 Backlight driver
 *
 * Copyright (C) 2011-2012 Texas Instruments
 *
 * Author: Johan Hovold <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under  the terms of the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the License, or (at your
 * option) any later version.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/backlight.h>
#include <linux/fb.h>
#include <linux/slab.h>

#include <linux/mfd/lm3533.h>


#define LM3533_HVCTRLBANK_COUNT     2
#define LM3533_BL_MAX_BRIGHTNESS    255

#define LM3533_REG_CTRLBANK_AB_BCONF    0x1a


struct lm3533_bl {
    struct lm3533 *lm3533;
    struct lm3533_ctrlbank cb;
    struct backlight_device *bd;
    int id;
};


static inline int lm3533_bl_get_ctrlbank_id(struct lm3533_bl *bl)
{
    return bl->id;
}

static int lm3533_bl_update_status(struct backlight_device *bd)
{
    struct lm3533_bl *bl = bl_get_data(bd);
    int brightness = bd->props.brightness;

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

    return lm3533_ctrlbank_set_brightness(&bl->cb, (u8)brightness);
}

static int lm3533_bl_get_brightness(struct backlight_device *bd)
{
    struct lm3533_bl *bl = bl_get_data(bd);
    u8 val;
    int ret;

    ret = lm3533_ctrlbank_get_brightness(&bl->cb, &val);
    if (ret)
        return ret;

    return val;
}

static const struct backlight_ops lm3533_bl_ops = {
    .get_brightness = lm3533_bl_get_brightness,
    .update_status  = lm3533_bl_update_status,
};

static ssize_t show_id(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    struct lm3533_bl *bl = dev_get_drvdata(dev);

    return scnprintf(buf, PAGE_SIZE, "%d\n", bl->id);
}

static ssize_t show_als_channel(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    struct lm3533_bl *bl = dev_get_drvdata(dev);
    unsigned channel = lm3533_bl_get_ctrlbank_id(bl);

    return scnprintf(buf, PAGE_SIZE, "%u\n", channel);
}

static ssize_t show_als_en(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    struct lm3533_bl *bl = dev_get_drvdata(dev);
    int ctrlbank = lm3533_bl_get_ctrlbank_id(bl);
    u8 val;
    u8 mask;
    bool enable;
    int ret;

    ret = lm3533_read(bl->lm3533, LM3533_REG_CTRLBANK_AB_BCONF, &val);
    if (ret)
        return ret;

    mask = 1 << (2 * ctrlbank);
    enable = val & mask;

    return scnprintf(buf, PAGE_SIZE, "%d\n", enable);
}

static ssize_t store_als_en(struct device *dev,
                    struct device_attribute *attr,
                    const char *buf, size_t len)
{
    struct lm3533_bl *bl = dev_get_drvdata(dev);
    int ctrlbank = lm3533_bl_get_ctrlbank_id(bl);
    int enable;
    u8 val;
    u8 mask;
    int ret;

    if (kstrtoint(buf, 0, &enable))
        return -EINVAL;

    mask = 1 << (2 * ctrlbank);

    if (enable)
        val = mask;
    else
        val = 0;

    ret = lm3533_update(bl->lm3533, LM3533_REG_CTRLBANK_AB_BCONF, val,
                                    mask);
    if (ret)
        return ret;

    return len;
}

static ssize_t show_linear(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    struct lm3533_bl *bl = dev_get_drvdata(dev);
    u8 val;
    u8 mask;
    int linear;
    int ret;

    ret = lm3533_read(bl->lm3533, LM3533_REG_CTRLBANK_AB_BCONF, &val);
    if (ret)
        return ret;

    mask = 1 << (2 * lm3533_bl_get_ctrlbank_id(bl) + 1);

    if (val & mask)
        linear = 1;
    else
        linear = 0;

    return scnprintf(buf, PAGE_SIZE, "%x\n", linear);
}

static ssize_t store_linear(struct device *dev,
                    struct device_attribute *attr,
                    const char *buf, size_t len)
{
    struct lm3533_bl *bl = dev_get_drvdata(dev);
    unsigned long linear;
    u8 mask;
    u8 val;
    int ret;

    if (kstrtoul(buf, 0, &linear))
        return -EINVAL;

    mask = 1 << (2 * lm3533_bl_get_ctrlbank_id(bl) + 1);

    if (linear)
        val = mask;
    else
        val = 0;

    ret = lm3533_update(bl->lm3533, LM3533_REG_CTRLBANK_AB_BCONF, val,
                                    mask);
    if (ret)
        return ret;

    return len;
}

static ssize_t show_pwm(struct device *dev,
                    struct device_attribute *attr,
                    char *buf)
{
    struct lm3533_bl *bl = dev_get_drvdata(dev);
    u8 val;
    int ret;

    ret = lm3533_ctrlbank_get_pwm(&bl->cb, &val);
    if (ret)
        return ret;

    return scnprintf(buf, PAGE_SIZE, "%u\n", val);
}

static ssize_t store_pwm(struct device *dev,
                    struct device_attribute *attr,
                    const char *buf, size_t len)
{
    struct lm3533_bl *bl = dev_get_drvdata(dev);
    u8 val;
    int ret;

    if (kstrtou8(buf, 0, &val))
        return -EINVAL;

    ret = lm3533_ctrlbank_set_pwm(&bl->cb, val);
    if (ret)
        return ret;

    return len;
}

static LM3533_ATTR_RO(als_channel);
static LM3533_ATTR_RW(als_en);
static LM3533_ATTR_RO(id);
static LM3533_ATTR_RW(linear);
static LM3533_ATTR_RW(pwm);

static struct attribute *lm3533_bl_attributes[] = {
    &dev_attr_als_channel.attr,
    &dev_attr_als_en.attr,
    &dev_attr_id.attr,
    &dev_attr_linear.attr,
    &dev_attr_pwm.attr,
    NULL,
};

static umode_t lm3533_bl_attr_is_visible(struct kobject *kobj,
                         struct attribute *attr, int n)
{
    struct device *dev = container_of(kobj, struct device, kobj);
    struct lm3533_bl *bl = dev_get_drvdata(dev);
    umode_t mode = attr->mode;

    if (attr == &dev_attr_als_channel.attr ||
                    attr == &dev_attr_als_en.attr) {
        if (!bl->lm3533->have_als)
            mode = 0;
    }

    return mode;
};

static struct attribute_group lm3533_bl_attribute_group = {
    .is_visible = lm3533_bl_attr_is_visible,
    .attrs      = lm3533_bl_attributes
};

static int __devinit lm3533_bl_setup(struct lm3533_bl *bl,
                    struct lm3533_bl_platform_data *pdata)
{
    int ret;

    ret = lm3533_ctrlbank_set_max_current(&bl->cb, pdata->max_current);
    if (ret)
        return ret;

    return lm3533_ctrlbank_set_pwm(&bl->cb, pdata->pwm);
}

static int __devinit lm3533_bl_probe(struct platform_device *pdev)
{
    struct lm3533 *lm3533;
    struct lm3533_bl_platform_data *pdata;
    struct lm3533_bl *bl;
    struct backlight_device *bd;
    struct backlight_properties props;
    int ret;

    dev_dbg(&pdev->dev, "%s\n", __func__);

    lm3533 = dev_get_drvdata(pdev->dev.parent);
    if (!lm3533)
        return -EINVAL;

    pdata = pdev->dev.platform_data;
    if (!pdata) {
        dev_err(&pdev->dev, "no platform data\n");
        return -EINVAL;
    }

    if (pdev->id < 0 || pdev->id >= LM3533_HVCTRLBANK_COUNT) {
        dev_err(&pdev->dev, "illegal backlight id %d\n", pdev->id);
        return -EINVAL;
    }

    bl = devm_kzalloc(&pdev->dev, sizeof(*bl), GFP_KERNEL);
    if (!bl) {
        dev_err(&pdev->dev,
                "failed to allocate memory for backlight\n");
        return -ENOMEM;
    }

    bl->lm3533 = lm3533;
    bl->id = pdev->id;

    bl->cb.lm3533 = lm3533;
    bl->cb.id = lm3533_bl_get_ctrlbank_id(bl);
    bl->cb.dev = NULL;          /* until registered */

    memset(&props, 0, sizeof(props));
    props.type = BACKLIGHT_RAW;
    props.max_brightness = LM3533_BL_MAX_BRIGHTNESS;
    props.brightness = pdata->default_brightness;
    bd = backlight_device_register(pdata->name, pdev->dev.parent, bl,
                        &lm3533_bl_ops, &props);
    if (IS_ERR(bd)) {
        dev_err(&pdev->dev, "failed to register backlight device\n");
        return PTR_ERR(bd);
    }

    bl->bd = bd;
    bl->cb.dev = &bl->bd->dev;

    platform_set_drvdata(pdev, bl);

    ret = sysfs_create_group(&bd->dev.kobj, &lm3533_bl_attribute_group);
    if (ret < 0) {
        dev_err(&pdev->dev, "failed to create sysfs attributes\n");
        goto err_unregister;
    }

    backlight_update_status(bd);

    ret = lm3533_bl_setup(bl, pdata);
    if (ret)
        goto err_sysfs_remove;

    ret = lm3533_ctrlbank_enable(&bl->cb);
    if (ret)
        goto err_sysfs_remove;

    return 0;

err_sysfs_remove:
    sysfs_remove_group(&bd->dev.kobj, &lm3533_bl_attribute_group);
err_unregister:
    backlight_device_unregister(bd);

    return ret;
}

static int __devexit lm3533_bl_remove(struct platform_device *pdev)
{
    struct lm3533_bl *bl = platform_get_drvdata(pdev);
    struct backlight_device *bd = bl->bd;

    dev_dbg(&bd->dev, "%s\n", __func__);

    bd->props.power = FB_BLANK_POWERDOWN;
    bd->props.brightness = 0;

    lm3533_ctrlbank_disable(&bl->cb);
    sysfs_remove_group(&bd->dev.kobj, &lm3533_bl_attribute_group);
    backlight_device_unregister(bd);

    return 0;
}

#ifdef CONFIG_PM
static int lm3533_bl_suspend(struct platform_device *pdev, pm_message_t state)
{
    struct lm3533_bl *bl = platform_get_drvdata(pdev);

    dev_dbg(&pdev->dev, "%s\n", __func__);

    return lm3533_ctrlbank_disable(&bl->cb);
}

static int lm3533_bl_resume(struct platform_device *pdev)
{
    struct lm3533_bl *bl = platform_get_drvdata(pdev);

    dev_dbg(&pdev->dev, "%s\n", __func__);

    return lm3533_ctrlbank_enable(&bl->cb);
}
#else
#define lm3533_bl_suspend   NULL
#define lm3533_bl_resume    NULL
#endif

static void lm3533_bl_shutdown(struct platform_device *pdev)
{
    struct lm3533_bl *bl = platform_get_drvdata(pdev);

    dev_dbg(&pdev->dev, "%s\n", __func__);

    lm3533_ctrlbank_disable(&bl->cb);
}

static struct platform_driver lm3533_bl_driver = {
    .driver = {
        .name   = "lm3533-backlight",
        .owner  = THIS_MODULE,
    },
    .probe      = lm3533_bl_probe,
    .remove     = __devexit_p(lm3533_bl_remove),
    .shutdown   = lm3533_bl_shutdown,
    .suspend    = lm3533_bl_suspend,
    .resume     = lm3533_bl_resume,
};
module_platform_driver(lm3533_bl_driver);

MODULE_AUTHOR("Johan Hovold <[email protected]>");
MODULE_DESCRIPTION("LM3533 Backlight driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:lm3533-backlight");