// SPDX-License-Identifier: GPL-2.0
/*
 * LG.Philips LB035Q02 LCD Panel Driver
 *
 * Copyright (C) 2019 Texas Instruments Incorporated
 *
 * Based on the omapdrm-specific panel-lgphilips-lb035q02 driver
 *
 * Copyright (C) 2013 Texas Instruments Incorporated
 * Author: Tomi Valkeinen <tomi.valkeinen@ti.com>
 *
 * Based on a driver by: Steve Sakoman <steve@sakoman.com>
 */

#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/spi/spi.h>

#include <drm/drm_connector.h>
#include <drm/drm_modes.h>
#include <drm/drm_panel.h>

struct lb035q02_device {
        struct drm_panel panel;

        struct spi_device *spi;
        struct gpio_desc *enable_gpio;
};

#define to_lb035q02_device(p) container_of(p, struct lb035q02_device, panel)

static int lb035q02_write(struct lb035q02_device *lcd, u16 reg, u16 val)
{
        struct spi_message msg;
        struct spi_transfer index_xfer = {
                .len            = 3,
                .cs_change      = 1,
        };
        struct spi_transfer value_xfer = {
                .len            = 3,
        };
        u8      buffer[16];

        spi_message_init(&msg);

        /* register index */
        buffer[0] = 0x70;
        buffer[1] = 0x00;
        buffer[2] = reg & 0x7f;
        index_xfer.tx_buf = buffer;
        spi_message_add_tail(&index_xfer, &msg);

        /* register value */
        buffer[4] = 0x72;
        buffer[5] = val >> 8;
        buffer[6] = val;
        value_xfer.tx_buf = buffer + 4;
        spi_message_add_tail(&value_xfer, &msg);

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

static int lb035q02_init(struct lb035q02_device *lcd)
{
        /* Init sequence from page 28 of the lb035q02 spec. */
        static const struct {
                u16 index;
                u16 value;
        } init_data[] = {
                { 0x01, 0x6300 },
                { 0x02, 0x0200 },
                { 0x03, 0x0177 },
                { 0x04, 0x04c7 },
                { 0x05, 0xffc0 },
                { 0x06, 0xe806 },
                { 0x0a, 0x4008 },
                { 0x0b, 0x0000 },
                { 0x0d, 0x0030 },
                { 0x0e, 0x2800 },
                { 0x0f, 0x0000 },
                { 0x16, 0x9f80 },
                { 0x17, 0x0a0f },
                { 0x1e, 0x00c1 },
                { 0x30, 0x0300 },
                { 0x31, 0x0007 },
                { 0x32, 0x0000 },
                { 0x33, 0x0000 },
                { 0x34, 0x0707 },
                { 0x35, 0x0004 },
                { 0x36, 0x0302 },
                { 0x37, 0x0202 },
                { 0x3a, 0x0a0d },
                { 0x3b, 0x0806 },
        };

        unsigned int i;
        int ret;

        for (i = 0; i < ARRAY_SIZE(init_data); ++i) {
                ret = lb035q02_write(lcd, init_data[i].index,
                                     init_data[i].value);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int lb035q02_disable(struct drm_panel *panel)
{
        struct lb035q02_device *lcd = to_lb035q02_device(panel);

        gpiod_set_value_cansleep(lcd->enable_gpio, 0);

        return 0;
}

static int lb035q02_enable(struct drm_panel *panel)
{
        struct lb035q02_device *lcd = to_lb035q02_device(panel);

        gpiod_set_value_cansleep(lcd->enable_gpio, 1);

        return 0;
}

static const struct drm_display_mode lb035q02_mode = {
        .clock = 6500,
        .hdisplay = 320,
        .hsync_start = 320 + 20,
        .hsync_end = 320 + 20 + 2,
        .htotal = 320 + 20 + 2 + 68,
        .vdisplay = 240,
        .vsync_start = 240 + 4,
        .vsync_end = 240 + 4 + 2,
        .vtotal = 240 + 4 + 2 + 18,
        .type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
        .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
        .width_mm = 70,
        .height_mm = 53,
};

static int lb035q02_get_modes(struct drm_panel *panel,
                              struct drm_connector *connector)
{
        struct drm_display_mode *mode;

        mode = drm_mode_duplicate(connector->dev, &lb035q02_mode);
        if (!mode)
                return -ENOMEM;

        drm_mode_set_name(mode);
        drm_mode_probed_add(connector, mode);

        connector->display_info.width_mm = lb035q02_mode.width_mm;
        connector->display_info.height_mm = lb035q02_mode.height_mm;
        /*
         * FIXME: According to the datasheet pixel data is sampled on the
         * rising edge of the clock, but the code running on the Gumstix Overo
         * Palo35 indicates sampling on the negative edge. This should be
         * tested on a real device.
         */
        connector->display_info.bus_flags = DRM_BUS_FLAG_DE_HIGH
                                          | DRM_BUS_FLAG_SYNC_SAMPLE_POSEDGE
                                          | DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE;

        return 1;
}

static const struct drm_panel_funcs lb035q02_funcs = {
        .disable = lb035q02_disable,
        .enable = lb035q02_enable,
        .get_modes = lb035q02_get_modes,
};

static int lb035q02_probe(struct spi_device *spi)
{
        struct lb035q02_device *lcd;
        int ret;

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

        spi_set_drvdata(spi, lcd);
        lcd->spi = spi;

        lcd->enable_gpio = devm_gpiod_get(&spi->dev, "enable", GPIOD_OUT_LOW);
        if (IS_ERR(lcd->enable_gpio)) {
                dev_err(&spi->dev, "failed to parse enable gpio\n");
                return PTR_ERR(lcd->enable_gpio);
        }

        ret = lb035q02_init(lcd);
        if (ret < 0)
                return ret;

        drm_panel_init(&lcd->panel, &lcd->spi->dev, &lb035q02_funcs,
                       DRM_MODE_CONNECTOR_DPI);

        drm_panel_add(&lcd->panel);

        return 0;
}

static int lb035q02_remove(struct spi_device *spi)
{
        struct lb035q02_device *lcd = spi_get_drvdata(spi);

        drm_panel_remove(&lcd->panel);
        drm_panel_disable(&lcd->panel);

        return 0;
}

static const struct of_device_id lb035q02_of_match[] = {
        { .compatible = "lgphilips,lb035q02", },
        { /* sentinel */ },
};

MODULE_DEVICE_TABLE(of, lb035q02_of_match);

static const struct spi_device_id lb035q02_ids[] = {
        { "lb035q02", 0 },
        { /* sentinel */ }
};

MODULE_DEVICE_TABLE(spi, lb035q02_ids);

static struct spi_driver lb035q02_driver = {
        .probe          = lb035q02_probe,
        .remove         = lb035q02_remove,
        .id_table       = lb035q02_ids,
        .driver         = {
                .name   = "panel-lg-lb035q02",
                .of_match_table = lb035q02_of_match,
        },
};

module_spi_driver(lb035q02_driver);

MODULE_AUTHOR("Tomi Valkeinen <tomi.valkeinen@ti.com>");
MODULE_DESCRIPTION("LG.Philips LB035Q02 LCD Panel driver");
MODULE_LICENSE("GPL");