// SPDX-License-Identifier: GPL-2.0-only
/*
 * Power control for Samsung LTV350QV Quarter VGA LCD Panel
 *
 * Copyright (C) 2006, 2007 Atmel Corporation
 */
#include <linux/delay.h>
#include <linux/err.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) <= LCD_POWER_REDUCED)

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

static int 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 = LCD_POWER_OFF;
        lcd->buffer = devm_kzalloc(&spi->dev, 8, GFP_KERNEL);
        if (!lcd->buffer)
                return -ENOMEM;

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

        lcd->ld = ld;

        ret = ltv350qv_power(lcd, LCD_POWER_ON);
        if (ret)
                return ret;

        spi_set_drvdata(spi, lcd);

        return 0;
}

static void ltv350qv_remove(struct spi_device *spi)
{
        struct ltv350qv *lcd = spi_get_drvdata(spi);

        ltv350qv_power(lcd, LCD_POWER_OFF);
}

#ifdef CONFIG_PM_SLEEP
static int ltv350qv_suspend(struct device *dev)
{
        struct ltv350qv *lcd = dev_get_drvdata(dev);

        return ltv350qv_power(lcd, LCD_POWER_OFF);
}

static int ltv350qv_resume(struct device *dev)
{
        struct ltv350qv *lcd = dev_get_drvdata(dev);

        return ltv350qv_power(lcd, LCD_POWER_ON);
}
#endif

static SIMPLE_DEV_PM_OPS(ltv350qv_pm_ops, ltv350qv_suspend, ltv350qv_resume);

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

        ltv350qv_power(lcd, LCD_POWER_OFF);
}

static struct spi_driver ltv350qv_driver = {
        .driver = {
                .name           = "ltv350qv",
                .pm             = &ltv350qv_pm_ops,
        },

        .probe          = ltv350qv_probe,
        .remove         = ltv350qv_remove,
        .shutdown       = ltv350qv_shutdown,
};

module_spi_driver(ltv350qv_driver);

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