tosa_bl.c

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/*
 *  LCD / Backlight control code for Sharp SL-6000x (tosa)
 *
 *  Copyright (c) 2005      Dirk Opfer
 *  Copyright (c) 2007,2008 Dmitry Baryshkov
 *
 *  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/module.h>
#include <linux/device.h>
#include <linux/spi/spi.h>
#include <linux/i2c.h>
#include <linux/gpio.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/slab.h>

#include <asm/mach/sharpsl_param.h>

#include <mach/tosa.h>

#define COMADJ_DEFAULT  97

#define DAC_CH1     0
#define DAC_CH2     1

struct tosa_bl_data {
    struct i2c_client *i2c;
    struct backlight_device *bl;

    int comadj;
};

static void tosa_bl_set_backlight(struct tosa_bl_data *data, int brightness)
{
    struct spi_device *spi = data->i2c->dev.platform_data;

    i2c_smbus_write_byte_data(data->i2c, DAC_CH1, data->comadj);

    /* SetBacklightDuty */
    i2c_smbus_write_byte_data(data->i2c, DAC_CH2, (u8)(brightness & 0xff));

    /* SetBacklightVR */
    gpio_set_value(TOSA_GPIO_BL_C20MA, brightness & 0x100);

    tosa_bl_enable(spi, brightness);
}

static int tosa_bl_update_status(struct backlight_device *dev)
{
    struct backlight_properties *props = &dev->props;
    struct tosa_bl_data *data = dev_get_drvdata(&dev->dev);
    int power = max(props->power, props->fb_blank);
    int brightness = props->brightness;

    if (power)
        brightness = 0;

    tosa_bl_set_backlight(data, brightness);

    return 0;
}

static int tosa_bl_get_brightness(struct backlight_device *dev)
{
    struct backlight_properties *props = &dev->props;

    return props->brightness;
}

static const struct backlight_ops bl_ops = {
    .get_brightness     = tosa_bl_get_brightness,
    .update_status      = tosa_bl_update_status,
};

static int __devinit tosa_bl_probe(struct i2c_client *client,
        const struct i2c_device_id *id)
{
    struct backlight_properties props;
    struct tosa_bl_data *data;
    int ret = 0;

    data = devm_kzalloc(&client->dev, sizeof(struct tosa_bl_data),
                GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    data->comadj = sharpsl_param.comadj == -1 ? COMADJ_DEFAULT : sharpsl_param.comadj;

    ret = devm_gpio_request(&client->dev, TOSA_GPIO_BL_C20MA, "backlight");
    if (ret) {
        dev_dbg(&data->bl->dev, "Unable to request gpio!\n");
        return ret;
    }
    ret = gpio_direction_output(TOSA_GPIO_BL_C20MA, 0);
    if (ret)
        return ret;

    i2c_set_clientdata(client, data);
    data->i2c = client;

    memset(&props, 0, sizeof(struct backlight_properties));
    props.type = BACKLIGHT_RAW;
    props.max_brightness = 512 - 1;
    data->bl = backlight_device_register("tosa-bl", &client->dev, data,
                         &bl_ops, &props);
    if (IS_ERR(data->bl)) {
        ret = PTR_ERR(data->bl);
        goto err_reg;
    }

    data->bl->props.brightness = 69;
    data->bl->props.power = FB_BLANK_UNBLANK;

    backlight_update_status(data->bl);

    return 0;

err_reg:
    data->bl = NULL;
    return ret;
}

static int __devexit tosa_bl_remove(struct i2c_client *client)
{
    struct tosa_bl_data *data = i2c_get_clientdata(client);

    backlight_device_unregister(data->bl);
    data->bl = NULL;

    return 0;
}

#ifdef CONFIG_PM
static int tosa_bl_suspend(struct i2c_client *client, pm_message_t pm)
{
    struct tosa_bl_data *data = i2c_get_clientdata(client);

    tosa_bl_set_backlight(data, 0);

    return 0;
}

static int tosa_bl_resume(struct i2c_client *client)
{
    struct tosa_bl_data *data = i2c_get_clientdata(client);

    backlight_update_status(data->bl);
    return 0;
}
#else
#define tosa_bl_suspend NULL
#define tosa_bl_resume NULL
#endif

static const struct i2c_device_id tosa_bl_id[] = {
    { "tosa-bl", 0 },
    { },
};


static struct i2c_driver tosa_bl_driver = {
    .driver = {
        .name       = "tosa-bl",
        .owner      = THIS_MODULE,
    },
    .probe      = tosa_bl_probe,
    .remove     = __devexit_p(tosa_bl_remove),
    .suspend    = tosa_bl_suspend,
    .resume     = tosa_bl_resume,
    .id_table   = tosa_bl_id,
};

module_i2c_driver(tosa_bl_driver);

MODULE_AUTHOR("Dmitry Baryshkov");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("LCD/Backlight control for Sharp SL-6000 PDA");