ltv350qv.c

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/*
 * Power control for Samsung LTV350QV Quarter VGA LCD Panel
 *
 * Copyright (C) 2006, 2007 Atmel Corporation
 *
 * 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/delay.h>
#include <linux/err.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/lcd.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>

#include "ltv350qv.h"

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

struct ltv350qv {
    struct spi_device   *spi;
    u8          *buffer;
    int         power;
    struct lcd_device   *ld;
};

/*
 * The power-on and power-off sequences are taken from the
 * LTV350QV-F04 data sheet from Samsung. The register definitions are
 * taken from the S6F2002 command list also from Samsung. Both
 * documents are distributed with the AVR32 Linux BSP CD from Atmel.
 *
 * There's still some voodoo going on here, but it's a lot better than
 * in the first incarnation of the driver where all we had was the raw
 * numbers from the initialization sequence.
 */
static int ltv350qv_write_reg(struct ltv350qv *lcd, u8 reg, u16 val)
{
    struct spi_message msg;
    struct spi_transfer index_xfer = {
        .len        = 3,
        .cs_change  = 1,
    };
    struct spi_transfer value_xfer = {
        .len        = 3,
    };

    spi_message_init(&msg);

    /* register index */
    lcd->buffer[0] = LTV_OPC_INDEX;
    lcd->buffer[1] = 0x00;
    lcd->buffer[2] = reg & 0x7f;
    index_xfer.tx_buf = lcd->buffer;
    spi_message_add_tail(&index_xfer, &msg);

    /* register value */
    lcd->buffer[4] = LTV_OPC_DATA;
    lcd->buffer[5] = val >> 8;
    lcd->buffer[6] = val;
    value_xfer.tx_buf = lcd->buffer + 4;
    spi_message_add_tail(&value_xfer, &msg);

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

/* The comments are taken straight from the data sheet */
static int ltv350qv_power_on(struct ltv350qv *lcd)
{
    int ret;

    /* Power On Reset Display off State */
    if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, 0x0000))
        goto err;
    usleep_range(15000, 16000);

    /* Power Setting Function 1 */
    if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE))
        goto err;
    if (ltv350qv_write_reg(lcd, LTV_PWRCTL2, LTV_VCOML_ENABLE))
        goto err_power1;

    /* Power Setting Function 2 */
    if (ltv350qv_write_reg(lcd, LTV_PWRCTL1,
                   LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5)
                   | LTV_SUPPLY_CURRENT(5)))
        goto err_power2;

    msleep(55);

    /* Instruction Setting */
    ret = ltv350qv_write_reg(lcd, LTV_IFCTL,
                 LTV_NMD | LTV_REV | LTV_NL(0x1d));
    ret |= ltv350qv_write_reg(lcd, LTV_DATACTL,
                  LTV_DS_SAME | LTV_CHS_480
                  | LTV_DF_RGB | LTV_RGB_BGR);
    ret |= ltv350qv_write_reg(lcd, LTV_ENTRY_MODE,
                  LTV_VSPL_ACTIVE_LOW
                  | LTV_HSPL_ACTIVE_LOW
                  | LTV_DPL_SAMPLE_RISING
                  | LTV_EPL_ACTIVE_LOW
                  | LTV_SS_RIGHT_TO_LEFT);
    ret |= ltv350qv_write_reg(lcd, LTV_GATECTL1, LTV_CLW(3));
    ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
                  LTV_NW_INV_1LINE | LTV_FWI(3));
    ret |= ltv350qv_write_reg(lcd, LTV_VBP, 0x000a);
    ret |= ltv350qv_write_reg(lcd, LTV_HBP, 0x0021);
    ret |= ltv350qv_write_reg(lcd, LTV_SOTCTL, LTV_SDT(3) | LTV_EQ(0));
    ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(0), 0x0103);
    ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(1), 0x0301);
    ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(2), 0x1f0f);
    ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(3), 0x1f0f);
    ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(4), 0x0707);
    ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(5), 0x0307);
    ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(6), 0x0707);
    ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(7), 0x0000);
    ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(8), 0x0004);
    ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(9), 0x0000);
    if (ret)
        goto err_settings;

    /* Wait more than 2 frames */
    msleep(20);

    /* Display On Sequence */
    ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1,
                 LTV_VCOM_DISABLE | LTV_VCOMOUT_ENABLE
                 | LTV_POWER_ON | LTV_DRIVE_CURRENT(5)
                 | LTV_SUPPLY_CURRENT(5));
    ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
                  LTV_NW_INV_1LINE | LTV_DSC | LTV_FWI(3));
    if (ret)
        goto err_disp_on;

    /* Display should now be ON. Phew. */
    return 0;

err_disp_on:
    /*
     * Try to recover. Error handling probably isn't very useful
     * at this point, just make a best effort to switch the panel
     * off.
     */
    ltv350qv_write_reg(lcd, LTV_PWRCTL1,
               LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5)
               | LTV_SUPPLY_CURRENT(5));
    ltv350qv_write_reg(lcd, LTV_GATECTL2,
               LTV_NW_INV_1LINE | LTV_FWI(3));
err_settings:
err_power2:
err_power1:
    ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000);
    usleep_range(1000, 1100);
err:
    ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);
    return -EIO;
}

static int ltv350qv_power_off(struct ltv350qv *lcd)
{
    int ret;

    /* Display Off Sequence */
    ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1,
                 LTV_VCOM_DISABLE
                 | LTV_DRIVE_CURRENT(5)
                 | LTV_SUPPLY_CURRENT(5));
    ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
                  LTV_NW_INV_1LINE | LTV_FWI(3));

    /* Power down setting 1 */
    ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000);

    /* Wait at least 1 ms */
    usleep_range(1000, 1100);

    /* Power down setting 2 */
    ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);

    /*
     * No point in trying to recover here. If we can't switch the
     * panel off, what are we supposed to do other than inform the
     * user about the failure?
     */
    if (ret)
        return -EIO;

    /* Display power should now be OFF */
    return 0;
}

static int ltv350qv_power(struct ltv350qv *lcd, int power)
{
    int ret = 0;

    if (POWER_IS_ON(power) && !POWER_IS_ON(lcd->power))
        ret = ltv350qv_power_on(lcd);
    else if (!POWER_IS_ON(power) && POWER_IS_ON(lcd->power))
        ret = ltv350qv_power_off(lcd);

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

    return ret;
}

static int ltv350qv_set_power(struct lcd_device *ld, int power)
{
    struct ltv350qv *lcd = lcd_get_data(ld);

    return ltv350qv_power(lcd, power);
}

static int ltv350qv_get_power(struct lcd_device *ld)
{
    struct ltv350qv *lcd = lcd_get_data(ld);

    return lcd->power;
}

static struct lcd_ops ltv_ops = {
    .get_power  = ltv350qv_get_power,
    .set_power  = ltv350qv_set_power,
};

static int __devinit ltv350qv_probe(struct spi_device *spi)
{
    struct ltv350qv *lcd;
    struct lcd_device *ld;
    int ret;

    lcd = devm_kzalloc(&spi->dev, sizeof(struct ltv350qv), GFP_KERNEL);
    if (!lcd)
        return -ENOMEM;

    lcd->spi = spi;
    lcd->power = FB_BLANK_POWERDOWN;
    lcd->buffer = devm_kzalloc(&spi->dev, 8, GFP_KERNEL);
    if (!lcd->buffer)
        return -ENOMEM;

    ld = lcd_device_register("ltv350qv", &spi->dev, lcd, &ltv_ops);
    if (IS_ERR(ld))
        return PTR_ERR(ld);

    lcd->ld = ld;

    ret = ltv350qv_power(lcd, FB_BLANK_UNBLANK);
    if (ret)
        goto out_unregister;

    dev_set_drvdata(&spi->dev, lcd);

    return 0;

out_unregister:
    lcd_device_unregister(ld);
    return ret;
}

static int __devexit ltv350qv_remove(struct spi_device *spi)
{
    struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);

    ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
    lcd_device_unregister(lcd->ld);

    return 0;
}

#ifdef CONFIG_PM
static int ltv350qv_suspend(struct spi_device *spi, pm_message_t state)
{
    struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);

    return ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
}

static int ltv350qv_resume(struct spi_device *spi)
{
    struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);

    return ltv350qv_power(lcd, FB_BLANK_UNBLANK);
}
#else
#define ltv350qv_suspend    NULL
#define ltv350qv_resume     NULL
#endif

/* Power down all displays on reboot, poweroff or halt */
static void ltv350qv_shutdown(struct spi_device *spi)
{
    struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);

    ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
}

static struct spi_driver ltv350qv_driver = {
    .driver = {
        .name       = "ltv350qv",
        .owner      = THIS_MODULE,
    },

    .probe      = ltv350qv_probe,
    .remove     = __devexit_p(ltv350qv_remove),
    .shutdown   = ltv350qv_shutdown,
    .suspend    = ltv350qv_suspend,
    .resume     = ltv350qv_resume,
};

module_spi_driver(ltv350qv_driver);

MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
MODULE_DESCRIPTION("Samsung LTV350QV LCD Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:ltv350qv");