s6e63m0.c

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/*
 * S6E63M0 AMOLED LCD panel driver.
 *
 * Author: InKi Dae  <[email protected]>
 *
 * Derived from drivers/video/omap/lcd-apollon.c
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include <linux/wait.h>
#include <linux/fb.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/spi/spi.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/lcd.h>
#include <linux/backlight.h>
#include <linux/module.h>

#include "s6e63m0_gamma.h"

#define SLEEPMSEC       0x1000
#define ENDDEF          0x2000
#define DEFMASK         0xFF00
#define COMMAND_ONLY        0xFE
#define DATA_ONLY       0xFF

#define MIN_BRIGHTNESS      0
#define MAX_BRIGHTNESS      10

#define POWER_IS_ON(pwr)    ((pwr) <= FB_BLANK_NORMAL)

struct s6e63m0 {
    struct device           *dev;
    struct spi_device       *spi;
    unsigned int            power;
    unsigned int            current_brightness;
    unsigned int            gamma_mode;
    unsigned int            gamma_table_count;
    struct lcd_device       *ld;
    struct backlight_device     *bd;
    struct lcd_platform_data    *lcd_pd;
};

static const unsigned short SEQ_PANEL_CONDITION_SET[] = {
    0xF8, 0x01,
    DATA_ONLY, 0x27,
    DATA_ONLY, 0x27,
    DATA_ONLY, 0x07,
    DATA_ONLY, 0x07,
    DATA_ONLY, 0x54,
    DATA_ONLY, 0x9f,
    DATA_ONLY, 0x63,
    DATA_ONLY, 0x86,
    DATA_ONLY, 0x1a,
    DATA_ONLY, 0x33,
    DATA_ONLY, 0x0d,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x00,

    ENDDEF, 0x0000
};

static const unsigned short SEQ_DISPLAY_CONDITION_SET[] = {
    0xf2, 0x02,
    DATA_ONLY, 0x03,
    DATA_ONLY, 0x1c,
    DATA_ONLY, 0x10,
    DATA_ONLY, 0x10,

    0xf7, 0x03,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x00,

    ENDDEF, 0x0000
};

static const unsigned short SEQ_GAMMA_SETTING[] = {
    0xfa, 0x00,
    DATA_ONLY, 0x18,
    DATA_ONLY, 0x08,
    DATA_ONLY, 0x24,
    DATA_ONLY, 0x64,
    DATA_ONLY, 0x56,
    DATA_ONLY, 0x33,
    DATA_ONLY, 0xb6,
    DATA_ONLY, 0xba,
    DATA_ONLY, 0xa8,
    DATA_ONLY, 0xac,
    DATA_ONLY, 0xb1,
    DATA_ONLY, 0x9d,
    DATA_ONLY, 0xc1,
    DATA_ONLY, 0xc1,
    DATA_ONLY, 0xb7,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x9c,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x9f,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0xd6,

    0xfa, 0x01,

    ENDDEF, 0x0000
};

static const unsigned short SEQ_ETC_CONDITION_SET[] = {
    0xf6, 0x00,
    DATA_ONLY, 0x8c,
    DATA_ONLY, 0x07,

    0xb3, 0xc,

    0xb5, 0x2c,
    DATA_ONLY, 0x12,
    DATA_ONLY, 0x0c,
    DATA_ONLY, 0x0a,
    DATA_ONLY, 0x10,
    DATA_ONLY, 0x0e,
    DATA_ONLY, 0x17,
    DATA_ONLY, 0x13,
    DATA_ONLY, 0x1f,
    DATA_ONLY, 0x1a,
    DATA_ONLY, 0x2a,
    DATA_ONLY, 0x24,
    DATA_ONLY, 0x1f,
    DATA_ONLY, 0x1b,
    DATA_ONLY, 0x1a,
    DATA_ONLY, 0x17,

    DATA_ONLY, 0x2b,
    DATA_ONLY, 0x26,
    DATA_ONLY, 0x22,
    DATA_ONLY, 0x20,
    DATA_ONLY, 0x3a,
    DATA_ONLY, 0x34,
    DATA_ONLY, 0x30,
    DATA_ONLY, 0x2c,
    DATA_ONLY, 0x29,
    DATA_ONLY, 0x26,
    DATA_ONLY, 0x25,
    DATA_ONLY, 0x23,
    DATA_ONLY, 0x21,
    DATA_ONLY, 0x20,
    DATA_ONLY, 0x1e,
    DATA_ONLY, 0x1e,

    0xb6, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x11,
    DATA_ONLY, 0x22,
    DATA_ONLY, 0x33,
    DATA_ONLY, 0x44,
    DATA_ONLY, 0x44,
    DATA_ONLY, 0x44,

    DATA_ONLY, 0x55,
    DATA_ONLY, 0x55,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,

    0xb7, 0x2c,
    DATA_ONLY, 0x12,
    DATA_ONLY, 0x0c,
    DATA_ONLY, 0x0a,
    DATA_ONLY, 0x10,
    DATA_ONLY, 0x0e,
    DATA_ONLY, 0x17,
    DATA_ONLY, 0x13,
    DATA_ONLY, 0x1f,
    DATA_ONLY, 0x1a,
    DATA_ONLY, 0x2a,
    DATA_ONLY, 0x24,
    DATA_ONLY, 0x1f,
    DATA_ONLY, 0x1b,
    DATA_ONLY, 0x1a,
    DATA_ONLY, 0x17,

    DATA_ONLY, 0x2b,
    DATA_ONLY, 0x26,
    DATA_ONLY, 0x22,
    DATA_ONLY, 0x20,
    DATA_ONLY, 0x3a,
    DATA_ONLY, 0x34,
    DATA_ONLY, 0x30,
    DATA_ONLY, 0x2c,
    DATA_ONLY, 0x29,
    DATA_ONLY, 0x26,
    DATA_ONLY, 0x25,
    DATA_ONLY, 0x23,
    DATA_ONLY, 0x21,
    DATA_ONLY, 0x20,
    DATA_ONLY, 0x1e,
    DATA_ONLY, 0x1e,

    0xb8, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x11,
    DATA_ONLY, 0x22,
    DATA_ONLY, 0x33,
    DATA_ONLY, 0x44,
    DATA_ONLY, 0x44,
    DATA_ONLY, 0x44,

    DATA_ONLY, 0x55,
    DATA_ONLY, 0x55,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,

    0xb9, 0x2c,
    DATA_ONLY, 0x12,
    DATA_ONLY, 0x0c,
    DATA_ONLY, 0x0a,
    DATA_ONLY, 0x10,
    DATA_ONLY, 0x0e,
    DATA_ONLY, 0x17,
    DATA_ONLY, 0x13,
    DATA_ONLY, 0x1f,
    DATA_ONLY, 0x1a,
    DATA_ONLY, 0x2a,
    DATA_ONLY, 0x24,
    DATA_ONLY, 0x1f,
    DATA_ONLY, 0x1b,
    DATA_ONLY, 0x1a,
    DATA_ONLY, 0x17,

    DATA_ONLY, 0x2b,
    DATA_ONLY, 0x26,
    DATA_ONLY, 0x22,
    DATA_ONLY, 0x20,
    DATA_ONLY, 0x3a,
    DATA_ONLY, 0x34,
    DATA_ONLY, 0x30,
    DATA_ONLY, 0x2c,
    DATA_ONLY, 0x29,
    DATA_ONLY, 0x26,
    DATA_ONLY, 0x25,
    DATA_ONLY, 0x23,
    DATA_ONLY, 0x21,
    DATA_ONLY, 0x20,
    DATA_ONLY, 0x1e,
    DATA_ONLY, 0x1e,

    0xba, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x11,
    DATA_ONLY, 0x22,
    DATA_ONLY, 0x33,
    DATA_ONLY, 0x44,
    DATA_ONLY, 0x44,
    DATA_ONLY, 0x44,

    DATA_ONLY, 0x55,
    DATA_ONLY, 0x55,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,
    DATA_ONLY, 0x66,

    0xc1, 0x4d,
    DATA_ONLY, 0x96,
    DATA_ONLY, 0x1d,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x01,
    DATA_ONLY, 0xdf,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x03,
    DATA_ONLY, 0x1f,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x00,
    DATA_ONLY, 0x03,
    DATA_ONLY, 0x06,
    DATA_ONLY, 0x09,
    DATA_ONLY, 0x0d,
    DATA_ONLY, 0x0f,
    DATA_ONLY, 0x12,
    DATA_ONLY, 0x15,
    DATA_ONLY, 0x18,

    0xb2, 0x10,
    DATA_ONLY, 0x10,
    DATA_ONLY, 0x0b,
    DATA_ONLY, 0x05,

    ENDDEF, 0x0000
};

static const unsigned short SEQ_ACL_ON[] = {
    /* ACL on */
    0xc0, 0x01,

    ENDDEF, 0x0000
};

static const unsigned short SEQ_ACL_OFF[] = {
    /* ACL off */
    0xc0, 0x00,

    ENDDEF, 0x0000
};

static const unsigned short SEQ_ELVSS_ON[] = {
    /* ELVSS on */
    0xb1, 0x0b,

    ENDDEF, 0x0000
};

static const unsigned short SEQ_ELVSS_OFF[] = {
    /* ELVSS off */
    0xb1, 0x0a,

    ENDDEF, 0x0000
};

static const unsigned short SEQ_STAND_BY_OFF[] = {
    0x11, COMMAND_ONLY,

    ENDDEF, 0x0000
};

static const unsigned short SEQ_STAND_BY_ON[] = {
    0x10, COMMAND_ONLY,

    ENDDEF, 0x0000
};

static const unsigned short SEQ_DISPLAY_ON[] = {
    0x29, COMMAND_ONLY,

    ENDDEF, 0x0000
};


static int s6e63m0_spi_write_byte(struct s6e63m0 *lcd, int addr, int data)
{
    u16 buf[1];
    struct spi_message msg;

    struct spi_transfer xfer = {
        .len        = 2,
        .tx_buf     = buf,
    };

    buf[0] = (addr << 8) | data;

    spi_message_init(&msg);
    spi_message_add_tail(&xfer, &msg);

    return spi_sync(lcd->spi, &msg);
}

static int s6e63m0_spi_write(struct s6e63m0 *lcd, unsigned char address,
    unsigned char command)
{
    int ret = 0;

    if (address != DATA_ONLY)
        ret = s6e63m0_spi_write_byte(lcd, 0x0, address);
    if (command != COMMAND_ONLY)
        ret = s6e63m0_spi_write_byte(lcd, 0x1, command);

    return ret;
}

static int s6e63m0_panel_send_sequence(struct s6e63m0 *lcd,
    const unsigned short *wbuf)
{
    int ret = 0, i = 0;

    while ((wbuf[i] & DEFMASK) != ENDDEF) {
        if ((wbuf[i] & DEFMASK) != SLEEPMSEC) {
            ret = s6e63m0_spi_write(lcd, wbuf[i], wbuf[i+1]);
            if (ret)
                break;
        } else
            udelay(wbuf[i+1]*1000);
        i += 2;
    }

    return ret;
}

static int _s6e63m0_gamma_ctl(struct s6e63m0 *lcd, const unsigned int *gamma)
{
    unsigned int i = 0;
    int ret = 0;

    /* disable gamma table updating. */
    ret = s6e63m0_spi_write(lcd, 0xfa, 0x00);
    if (ret) {
        dev_err(lcd->dev, "failed to disable gamma table updating.\n");
        goto gamma_err;
    }

    for (i = 0 ; i < GAMMA_TABLE_COUNT; i++) {
        ret = s6e63m0_spi_write(lcd, DATA_ONLY, gamma[i]);
        if (ret) {
            dev_err(lcd->dev, "failed to set gamma table.\n");
            goto gamma_err;
        }
    }

    /* update gamma table. */
    ret = s6e63m0_spi_write(lcd, 0xfa, 0x01);
    if (ret)
        dev_err(lcd->dev, "failed to update gamma table.\n");

gamma_err:
    return ret;
}

static int s6e63m0_gamma_ctl(struct s6e63m0 *lcd, int gamma)
{
    int ret = 0;

    ret = _s6e63m0_gamma_ctl(lcd, gamma_table.gamma_22_table[gamma]);

    return ret;
}


static int s6e63m0_ldi_init(struct s6e63m0 *lcd)
{
    int ret, i;
    const unsigned short *init_seq[] = {
        SEQ_PANEL_CONDITION_SET,
        SEQ_DISPLAY_CONDITION_SET,
        SEQ_GAMMA_SETTING,
        SEQ_ETC_CONDITION_SET,
        SEQ_ACL_ON,
        SEQ_ELVSS_ON,
    };

    for (i = 0; i < ARRAY_SIZE(init_seq); i++) {
        ret = s6e63m0_panel_send_sequence(lcd, init_seq[i]);
        if (ret)
            break;
    }

    return ret;
}

static int s6e63m0_ldi_enable(struct s6e63m0 *lcd)
{
    int ret = 0, i;
    const unsigned short *enable_seq[] = {
        SEQ_STAND_BY_OFF,
        SEQ_DISPLAY_ON,
    };

    for (i = 0; i < ARRAY_SIZE(enable_seq); i++) {
        ret = s6e63m0_panel_send_sequence(lcd, enable_seq[i]);
        if (ret)
            break;
    }

    return ret;
}

static int s6e63m0_ldi_disable(struct s6e63m0 *lcd)
{
    int ret;

    ret = s6e63m0_panel_send_sequence(lcd, SEQ_STAND_BY_ON);

    return ret;
}

static int s6e63m0_power_on(struct s6e63m0 *lcd)
{
    int ret = 0;
    struct lcd_platform_data *pd = NULL;
    struct backlight_device *bd = NULL;

    pd = lcd->lcd_pd;
    if (!pd) {
        dev_err(lcd->dev, "platform data is NULL.\n");
        return -EFAULT;
    }

    bd = lcd->bd;
    if (!bd) {
        dev_err(lcd->dev, "backlight device is NULL.\n");
        return -EFAULT;
    }

    if (!pd->power_on) {
        dev_err(lcd->dev, "power_on is NULL.\n");
        return -EFAULT;
    } else {
        pd->power_on(lcd->ld, 1);
        mdelay(pd->power_on_delay);
    }

    if (!pd->reset) {
        dev_err(lcd->dev, "reset is NULL.\n");
        return -EFAULT;
    } else {
        pd->reset(lcd->ld);
        mdelay(pd->reset_delay);
    }

    ret = s6e63m0_ldi_init(lcd);
    if (ret) {
        dev_err(lcd->dev, "failed to initialize ldi.\n");
        return ret;
    }

    ret = s6e63m0_ldi_enable(lcd);
    if (ret) {
        dev_err(lcd->dev, "failed to enable ldi.\n");
        return ret;
    }

    /* set brightness to current value after power on or resume. */
    ret = s6e63m0_gamma_ctl(lcd, bd->props.brightness);
    if (ret) {
        dev_err(lcd->dev, "lcd gamma setting failed.\n");
        return ret;
    }

    return 0;
}

static int s6e63m0_power_off(struct s6e63m0 *lcd)
{
    int ret = 0;
    struct lcd_platform_data *pd = NULL;

    pd = lcd->lcd_pd;
    if (!pd) {
        dev_err(lcd->dev, "platform data is NULL.\n");
        return -EFAULT;
    }

    ret = s6e63m0_ldi_disable(lcd);
    if (ret) {
        dev_err(lcd->dev, "lcd setting failed.\n");
        return -EIO;
    }

    mdelay(pd->power_off_delay);

    if (!pd->power_on) {
        dev_err(lcd->dev, "power_on is NULL.\n");
        return -EFAULT;
    } else
        pd->power_on(lcd->ld, 0);

    return 0;
}

static int s6e63m0_power(struct s6e63m0 *lcd, int power)
{
    int ret = 0;

    if (POWER_IS_ON(power) && !POWER_IS_ON(lcd->power))
        ret = s6e63m0_power_on(lcd);
    else if (!POWER_IS_ON(power) && POWER_IS_ON(lcd->power))
        ret = s6e63m0_power_off(lcd);

    if (!ret)
        lcd->power = power;

    return ret;
}

static int s6e63m0_set_power(struct lcd_device *ld, int power)
{
    struct s6e63m0 *lcd = lcd_get_data(ld);

    if (power != FB_BLANK_UNBLANK && power != FB_BLANK_POWERDOWN &&
        power != FB_BLANK_NORMAL) {
        dev_err(lcd->dev, "power value should be 0, 1 or 4.\n");
        return -EINVAL;
    }

    return s6e63m0_power(lcd, power);
}

static int s6e63m0_get_power(struct lcd_device *ld)
{
    struct s6e63m0 *lcd = lcd_get_data(ld);

    return lcd->power;
}

static int s6e63m0_get_brightness(struct backlight_device *bd)
{
    return bd->props.brightness;
}

static int s6e63m0_set_brightness(struct backlight_device *bd)
{
    int ret = 0, brightness = bd->props.brightness;
    struct s6e63m0 *lcd = bl_get_data(bd);

    if (brightness < MIN_BRIGHTNESS ||
        brightness > bd->props.max_brightness) {
        dev_err(&bd->dev, "lcd brightness should be %d to %d.\n",
            MIN_BRIGHTNESS, MAX_BRIGHTNESS);
        return -EINVAL;
    }

    ret = s6e63m0_gamma_ctl(lcd, bd->props.brightness);
    if (ret) {
        dev_err(&bd->dev, "lcd brightness setting failed.\n");
        return -EIO;
    }

    return ret;
}

static struct lcd_ops s6e63m0_lcd_ops = {
    .set_power = s6e63m0_set_power,
    .get_power = s6e63m0_get_power,
};

static const struct backlight_ops s6e63m0_backlight_ops  = {
    .get_brightness = s6e63m0_get_brightness,
    .update_status = s6e63m0_set_brightness,
};

static ssize_t s6e63m0_sysfs_show_gamma_mode(struct device *dev,
                      struct device_attribute *attr, char *buf)
{
    struct s6e63m0 *lcd = dev_get_drvdata(dev);
    char temp[10];

    switch (lcd->gamma_mode) {
    case 0:
        sprintf(temp, "2.2 mode\n");
        strcat(buf, temp);
        break;
    case 1:
        sprintf(temp, "1.9 mode\n");
        strcat(buf, temp);
        break;
    case 2:
        sprintf(temp, "1.7 mode\n");
        strcat(buf, temp);
        break;
    default:
        dev_info(dev, "gamma mode could be 0:2.2, 1:1.9 or 2:1.7)n");
        break;
    }

    return strlen(buf);
}

static ssize_t s6e63m0_sysfs_store_gamma_mode(struct device *dev,
                       struct device_attribute *attr,
                       const char *buf, size_t len)
{
    struct s6e63m0 *lcd = dev_get_drvdata(dev);
    struct backlight_device *bd = NULL;
    int brightness, rc;

    rc = kstrtouint(buf, 0, &lcd->gamma_mode);
    if (rc < 0)
        return rc;

    bd = lcd->bd;

    brightness = bd->props.brightness;

    switch (lcd->gamma_mode) {
    case 0:
        _s6e63m0_gamma_ctl(lcd, gamma_table.gamma_22_table[brightness]);
        break;
    case 1:
        _s6e63m0_gamma_ctl(lcd, gamma_table.gamma_19_table[brightness]);
        break;
    case 2:
        _s6e63m0_gamma_ctl(lcd, gamma_table.gamma_17_table[brightness]);
        break;
    default:
        dev_info(dev, "gamma mode could be 0:2.2, 1:1.9 or 2:1.7\n");
        _s6e63m0_gamma_ctl(lcd, gamma_table.gamma_22_table[brightness]);
        break;
    }
    return len;
}

static DEVICE_ATTR(gamma_mode, 0644,
        s6e63m0_sysfs_show_gamma_mode, s6e63m0_sysfs_store_gamma_mode);

static ssize_t s6e63m0_sysfs_show_gamma_table(struct device *dev,
                      struct device_attribute *attr, char *buf)
{
    struct s6e63m0 *lcd = dev_get_drvdata(dev);
    char temp[3];

    sprintf(temp, "%d\n", lcd->gamma_table_count);
    strcpy(buf, temp);

    return strlen(buf);
}
static DEVICE_ATTR(gamma_table, 0444,
        s6e63m0_sysfs_show_gamma_table, NULL);

static int __devinit s6e63m0_probe(struct spi_device *spi)
{
    int ret = 0;
    struct s6e63m0 *lcd = NULL;
    struct lcd_device *ld = NULL;
    struct backlight_device *bd = NULL;
    struct backlight_properties props;

    lcd = devm_kzalloc(&spi->dev, sizeof(struct s6e63m0), GFP_KERNEL);
    if (!lcd)
        return -ENOMEM;

    /* s6e63m0 lcd panel uses 3-wire 9bits SPI Mode. */
    spi->bits_per_word = 9;

    ret = spi_setup(spi);
    if (ret < 0) {
        dev_err(&spi->dev, "spi setup failed.\n");
        return ret;
    }

    lcd->spi = spi;
    lcd->dev = &spi->dev;

    lcd->lcd_pd = (struct lcd_platform_data *)spi->dev.platform_data;
    if (!lcd->lcd_pd) {
        dev_err(&spi->dev, "platform data is NULL.\n");
        return -EFAULT;
    }

    ld = lcd_device_register("s6e63m0", &spi->dev, lcd, &s6e63m0_lcd_ops);
    if (IS_ERR(ld))
        return PTR_ERR(ld);

    lcd->ld = ld;

    memset(&props, 0, sizeof(struct backlight_properties));
    props.type = BACKLIGHT_RAW;
    props.max_brightness = MAX_BRIGHTNESS;

    bd = backlight_device_register("s6e63m0bl-bl", &spi->dev, lcd,
        &s6e63m0_backlight_ops, &props);
    if (IS_ERR(bd)) {
        ret =  PTR_ERR(bd);
        goto out_lcd_unregister;
    }

    bd->props.brightness = MAX_BRIGHTNESS;
    lcd->bd = bd;

    /*
     * it gets gamma table count available so it gets user
     * know that.
     */
    lcd->gamma_table_count =
        sizeof(gamma_table) / (MAX_GAMMA_LEVEL * sizeof(int));

    ret = device_create_file(&(spi->dev), &dev_attr_gamma_mode);
    if (ret < 0)
        dev_err(&(spi->dev), "failed to add sysfs entries\n");

    ret = device_create_file(&(spi->dev), &dev_attr_gamma_table);
    if (ret < 0)
        dev_err(&(spi->dev), "failed to add sysfs entries\n");

    /*
     * if lcd panel was on from bootloader like u-boot then
     * do not lcd on.
     */
    if (!lcd->lcd_pd->lcd_enabled) {
        /*
         * if lcd panel was off from bootloader then
         * current lcd status is powerdown and then
         * it enables lcd panel.
         */
        lcd->power = FB_BLANK_POWERDOWN;

        s6e63m0_power(lcd, FB_BLANK_UNBLANK);
    } else
        lcd->power = FB_BLANK_UNBLANK;

    dev_set_drvdata(&spi->dev, lcd);

    dev_info(&spi->dev, "s6e63m0 panel driver has been probed.\n");

    return 0;

out_lcd_unregister:
    lcd_device_unregister(ld);
    return ret;
}

static int __devexit s6e63m0_remove(struct spi_device *spi)
{
    struct s6e63m0 *lcd = dev_get_drvdata(&spi->dev);

    s6e63m0_power(lcd, FB_BLANK_POWERDOWN);
    device_remove_file(&spi->dev, &dev_attr_gamma_table);
    device_remove_file(&spi->dev, &dev_attr_gamma_mode);
    backlight_device_unregister(lcd->bd);
    lcd_device_unregister(lcd->ld);

    return 0;
}

#if defined(CONFIG_PM)
static unsigned int before_power;

static int s6e63m0_suspend(struct spi_device *spi, pm_message_t mesg)
{
    int ret = 0;
    struct s6e63m0 *lcd = dev_get_drvdata(&spi->dev);

    dev_dbg(&spi->dev, "lcd->power = %d\n", lcd->power);

    before_power = lcd->power;

    /*
     * when lcd panel is suspend, lcd panel becomes off
     * regardless of status.
     */
    ret = s6e63m0_power(lcd, FB_BLANK_POWERDOWN);

    return ret;
}

static int s6e63m0_resume(struct spi_device *spi)
{
    int ret = 0;
    struct s6e63m0 *lcd = dev_get_drvdata(&spi->dev);

    /*
     * after suspended, if lcd panel status is FB_BLANK_UNBLANK
     * (at that time, before_power is FB_BLANK_UNBLANK) then
     * it changes that status to FB_BLANK_POWERDOWN to get lcd on.
     */
    if (before_power == FB_BLANK_UNBLANK)
        lcd->power = FB_BLANK_POWERDOWN;

    dev_dbg(&spi->dev, "before_power = %d\n", before_power);

    ret = s6e63m0_power(lcd, before_power);

    return ret;
}
#else
#define s6e63m0_suspend     NULL
#define s6e63m0_resume      NULL
#endif

/* Power down all displays on reboot, poweroff or halt. */
static void s6e63m0_shutdown(struct spi_device *spi)
{
    struct s6e63m0 *lcd = dev_get_drvdata(&spi->dev);

    s6e63m0_power(lcd, FB_BLANK_POWERDOWN);
}

static struct spi_driver s6e63m0_driver = {
    .driver = {
        .name   = "s6e63m0",
        .owner  = THIS_MODULE,
    },
    .probe      = s6e63m0_probe,
    .remove     = __devexit_p(s6e63m0_remove),
    .shutdown   = s6e63m0_shutdown,
    .suspend    = s6e63m0_suspend,
    .resume     = s6e63m0_resume,
};

module_spi_driver(s6e63m0_driver);

MODULE_AUTHOR("InKi Dae <[email protected]>");
MODULE_DESCRIPTION("S6E63M0 LCD Driver");
MODULE_LICENSE("GPL");