// SPDX-License-Identifier: GPL-2.0-only
/*
 * l4f00242t03.c -- support for Epson L4F00242T03 LCD
 *
 * Copyright 2007-2009 Freescale Semiconductor, Inc. All Rights Reserved.
 *
 * Copyright (c) 2009 Alberto Panizzo <maramaopercheseimorto@gmail.com>
 *      Inspired by Marek Vasut work in l4f00242t03.c
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/gpio/consumer.h>
#include <linux/lcd.h>
#include <linux/slab.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>

struct l4f00242t03_priv {
        struct spi_device       *spi;
        struct lcd_device       *ld;
        int lcd_state;
        struct regulator *io_reg;
        struct regulator *core_reg;
        struct gpio_desc *reset;
        struct gpio_desc *enable;
};

static void l4f00242t03_reset(struct gpio_desc *gpiod)
{
        pr_debug("l4f00242t03_reset.\n");
        gpiod_set_value(gpiod, 1);
        mdelay(100);
        gpiod_set_value(gpiod, 0);
        mdelay(10);     /* tRES >= 100us */
        gpiod_set_value(gpiod, 1);
        mdelay(20);
}

#define param(x) ((x) | 0x100)

static void l4f00242t03_lcd_init(struct spi_device *spi)
{
        struct l4f00242t03_priv *priv = spi_get_drvdata(spi);
        const u16 cmd[] = { 0x36, param(0), 0x3A, param(0x60) };
        int ret;

        dev_dbg(&spi->dev, "initializing LCD\n");

        ret = regulator_set_voltage(priv->io_reg, 1800000, 1800000);
        if (ret) {
                dev_err(&spi->dev, "failed to set the IO regulator voltage.\n");
                return;
        }
        ret = regulator_enable(priv->io_reg);
        if (ret) {
                dev_err(&spi->dev, "failed to enable the IO regulator.\n");
                return;
        }

        ret = regulator_set_voltage(priv->core_reg, 2800000, 2800000);
        if (ret) {
                dev_err(&spi->dev, "failed to set the core regulator voltage.\n");
                regulator_disable(priv->io_reg);
                return;
        }
        ret = regulator_enable(priv->core_reg);
        if (ret) {
                dev_err(&spi->dev, "failed to enable the core regulator.\n");
                regulator_disable(priv->io_reg);
                return;
        }

        l4f00242t03_reset(priv->reset);

        gpiod_set_value(priv->enable, 1);
        msleep(60);
        spi_write(spi, (const u8 *)cmd, ARRAY_SIZE(cmd) * sizeof(u16));
}

static void l4f00242t03_lcd_powerdown(struct spi_device *spi)
{
        struct l4f00242t03_priv *priv = spi_get_drvdata(spi);

        dev_dbg(&spi->dev, "Powering down LCD\n");

        gpiod_set_value(priv->enable, 0);

        regulator_disable(priv->io_reg);
        regulator_disable(priv->core_reg);
}

static int l4f00242t03_lcd_power_get(struct lcd_device *ld)
{
        struct l4f00242t03_priv *priv = lcd_get_data(ld);

        return priv->lcd_state;
}

static int l4f00242t03_lcd_power_set(struct lcd_device *ld, int power)
{
        struct l4f00242t03_priv *priv = lcd_get_data(ld);
        struct spi_device *spi = priv->spi;

        const u16 slpout = 0x11;
        const u16 dison = 0x29;

        const u16 slpin = 0x10;
        const u16 disoff = 0x28;

        if (power <= LCD_POWER_REDUCED) {
                if (priv->lcd_state <= LCD_POWER_REDUCED) {
                        /* Do nothing, the LCD is running */
                } else if (priv->lcd_state < LCD_POWER_OFF) {
                        dev_dbg(&spi->dev, "Resuming LCD\n");

                        spi_write(spi, (const u8 *)&slpout, sizeof(u16));
                        msleep(60);
                        spi_write(spi, (const u8 *)&dison, sizeof(u16));
                } else {
                        /* priv->lcd_state == LCD_POWER_OFF */
                        l4f00242t03_lcd_init(spi);
                        priv->lcd_state = LCD_POWER_REDUCED_VSYNC_SUSPEND;
                        l4f00242t03_lcd_power_set(priv->ld, power);
                }
        } else if (power < LCD_POWER_OFF) {
                if (priv->lcd_state <= LCD_POWER_REDUCED) {
                        /* Send the display in standby */
                        dev_dbg(&spi->dev, "Standby the LCD\n");

                        spi_write(spi, (const u8 *)&disoff, sizeof(u16));
                        msleep(60);
                        spi_write(spi, (const u8 *)&slpin, sizeof(u16));
                } else if (priv->lcd_state < LCD_POWER_OFF) {
                        /* Do nothing, the LCD is already in standby */
                } else {
                        /* priv->lcd_state == LCD_POWER_OFF */
                        l4f00242t03_lcd_init(spi);
                        priv->lcd_state = LCD_POWER_ON;
                        l4f00242t03_lcd_power_set(ld, power);
                }
        } else {
                /* power == LCD_POWER_OFF */
                if (priv->lcd_state != LCD_POWER_OFF) {
                        /* Clear the screen before shutting down */
                        spi_write(spi, (const u8 *)&disoff, sizeof(u16));
                        msleep(60);
                        l4f00242t03_lcd_powerdown(spi);
                }
        }

        priv->lcd_state = power;

        return 0;
}

static const struct lcd_ops l4f_ops = {
        .set_power      = l4f00242t03_lcd_power_set,
        .get_power      = l4f00242t03_lcd_power_get,
};

static int l4f00242t03_probe(struct spi_device *spi)
{
        struct l4f00242t03_priv *priv;
        int ret;

        priv = devm_kzalloc(&spi->dev, sizeof(struct l4f00242t03_priv),
                                GFP_KERNEL);
        if (priv == NULL)
                return -ENOMEM;

        spi_set_drvdata(spi, priv);
        spi->bits_per_word = 9;
        ret = spi_setup(spi);
        if (ret < 0)
                return dev_err_probe(&spi->dev, ret, "Unable to setup spi.\n");

        priv->spi = spi;

        priv->reset = devm_gpiod_get(&spi->dev, "reset", GPIOD_OUT_HIGH);
        if (IS_ERR(priv->reset))
                return dev_err_probe(&spi->dev, PTR_ERR(priv->reset),
                                     "Unable to get the lcd l4f00242t03 reset gpio.\n");
        gpiod_set_consumer_name(priv->reset, "lcd l4f00242t03 reset");

        priv->enable = devm_gpiod_get(&spi->dev, "enable", GPIOD_OUT_LOW);
        if (IS_ERR(priv->enable))
                return dev_err_probe(&spi->dev, PTR_ERR(priv->enable),
                                     "Unable to get the lcd l4f00242t03 data en gpio.\n");
        gpiod_set_consumer_name(priv->enable, "lcd l4f00242t03 data enable");

        priv->io_reg = devm_regulator_get(&spi->dev, "vdd");
        if (IS_ERR(priv->io_reg))
                return dev_err_probe(&spi->dev, PTR_ERR(priv->io_reg),
                                     "%s: Unable to get the IO regulator\n",
                                     __func__);

        priv->core_reg = devm_regulator_get(&spi->dev, "vcore");
        if (IS_ERR(priv->core_reg))
                return dev_err_probe(&spi->dev, PTR_ERR(priv->core_reg),
                                     "%s: Unable to get the core regulator\n",
                                     __func__);

        priv->ld = devm_lcd_device_register(&spi->dev, "l4f00242t03", &spi->dev,
                                        priv, &l4f_ops);
        if (IS_ERR(priv->ld))
                return PTR_ERR(priv->ld);

        /* Init the LCD */
        l4f00242t03_lcd_init(spi);
        priv->lcd_state = LCD_POWER_REDUCED_VSYNC_SUSPEND;
        l4f00242t03_lcd_power_set(priv->ld, LCD_POWER_ON);

        dev_info(&spi->dev, "Epson l4f00242t03 lcd probed.\n");

        return 0;
}

static void l4f00242t03_remove(struct spi_device *spi)
{
        struct l4f00242t03_priv *priv = spi_get_drvdata(spi);

        l4f00242t03_lcd_power_set(priv->ld, LCD_POWER_OFF);
}

static void l4f00242t03_shutdown(struct spi_device *spi)
{
        struct l4f00242t03_priv *priv = spi_get_drvdata(spi);

        if (priv)
                l4f00242t03_lcd_power_set(priv->ld, LCD_POWER_OFF);

}

static struct spi_driver l4f00242t03_driver = {
        .driver = {
                .name   = "l4f00242t03",
        },
        .probe          = l4f00242t03_probe,
        .remove         = l4f00242t03_remove,
        .shutdown       = l4f00242t03_shutdown,
};

module_spi_driver(l4f00242t03_driver);

MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>");
MODULE_DESCRIPTION("EPSON L4F00242T03 LCD");
MODULE_LICENSE("GPL v2");