/*
 * Copyright (C) 2014 NVIDIA 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/backlight.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>

#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_mipi_dsi.h>
#include <drm/drm_panel.h>

#include <video/mipi_display.h>

struct sharp_panel {
        struct drm_panel base;
        /* the datasheet refers to them as DSI-LINK1 and DSI-LINK2 */
        struct mipi_dsi_device *link1;
        struct mipi_dsi_device *link2;

        struct backlight_device *backlight;
        struct regulator *supply;

        bool prepared;
        bool enabled;

        const struct drm_display_mode *mode;
};

static inline struct sharp_panel *to_sharp_panel(struct drm_panel *panel)
{
        return container_of(panel, struct sharp_panel, base);
}

static void sharp_wait_frames(struct sharp_panel *sharp, unsigned int frames)
{
        unsigned int refresh = drm_mode_vrefresh(sharp->mode);

        if (WARN_ON(frames > refresh))
                return;

        msleep(1000 / (refresh / frames));
}

static int sharp_panel_write(struct sharp_panel *sharp, u16 offset, u8 value)
{
        u8 payload[3] = { offset >> 8, offset & 0xff, value };
        struct mipi_dsi_device *dsi = sharp->link1;
        ssize_t err;

        err = mipi_dsi_generic_write(dsi, payload, sizeof(payload));
        if (err < 0) {
                dev_err(&dsi->dev, "failed to write %02x to %04x: %zd\n",
                        value, offset, err);
                return err;
        }

        err = mipi_dsi_dcs_nop(dsi);
        if (err < 0) {
                dev_err(&dsi->dev, "failed to send DCS nop: %zd\n", err);
                return err;
        }

        usleep_range(10, 20);

        return 0;
}

static __maybe_unused int sharp_panel_read(struct sharp_panel *sharp,
                                           u16 offset, u8 *value)
{
        ssize_t err;

        cpu_to_be16s(&offset);

        err = mipi_dsi_generic_read(sharp->link1, &offset, sizeof(offset),
                                    value, sizeof(*value));
        if (err < 0)
                dev_err(&sharp->link1->dev, "failed to read from %04x: %zd\n",
                        offset, err);

        return err;
}

static int sharp_panel_disable(struct drm_panel *panel)
{
        struct sharp_panel *sharp = to_sharp_panel(panel);

        if (!sharp->enabled)
                return 0;

        backlight_disable(sharp->backlight);

        sharp->enabled = false;

        return 0;
}

static int sharp_panel_unprepare(struct drm_panel *panel)
{
        struct sharp_panel *sharp = to_sharp_panel(panel);
        int err;

        if (!sharp->prepared)
                return 0;

        sharp_wait_frames(sharp, 4);

        err = mipi_dsi_dcs_set_display_off(sharp->link1);
        if (err < 0)
                dev_err(panel->dev, "failed to set display off: %d\n", err);

        err = mipi_dsi_dcs_enter_sleep_mode(sharp->link1);
        if (err < 0)
                dev_err(panel->dev, "failed to enter sleep mode: %d\n", err);

        msleep(120);

        regulator_disable(sharp->supply);

        sharp->prepared = false;

        return 0;
}

static int sharp_setup_symmetrical_split(struct mipi_dsi_device *left,
                                         struct mipi_dsi_device *right,
                                         const struct drm_display_mode *mode)
{
        int err;

        err = mipi_dsi_dcs_set_column_address(left, 0, mode->hdisplay / 2 - 1);
        if (err < 0) {
                dev_err(&left->dev, "failed to set column address: %d\n", err);
                return err;
        }

        err = mipi_dsi_dcs_set_page_address(left, 0, mode->vdisplay - 1);
        if (err < 0) {
                dev_err(&left->dev, "failed to set page address: %d\n", err);
                return err;
        }

        err = mipi_dsi_dcs_set_column_address(right, mode->hdisplay / 2,
                                              mode->hdisplay - 1);
        if (err < 0) {
                dev_err(&right->dev, "failed to set column address: %d\n", err);
                return err;
        }

        err = mipi_dsi_dcs_set_page_address(right, 0, mode->vdisplay - 1);
        if (err < 0) {
                dev_err(&right->dev, "failed to set page address: %d\n", err);
                return err;
        }

        return 0;
}

static int sharp_panel_prepare(struct drm_panel *panel)
{
        struct sharp_panel *sharp = to_sharp_panel(panel);
        u8 format = MIPI_DCS_PIXEL_FMT_24BIT;
        int err;

        if (sharp->prepared)
                return 0;

        err = regulator_enable(sharp->supply);
        if (err < 0)
                return err;

        /*
         * According to the datasheet, the panel needs around 10 ms to fully
         * power up. At least another 120 ms is required before exiting sleep
         * mode to make sure the panel is ready. Throw in another 20 ms for
         * good measure.
         */
        msleep(150);

        err = mipi_dsi_dcs_exit_sleep_mode(sharp->link1);
        if (err < 0) {
                dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
                goto poweroff;
        }

        /*
         * The MIPI DCS specification mandates this delay only between the
         * exit_sleep_mode and enter_sleep_mode commands, so it isn't strictly
         * necessary here.
         */
        /*
        msleep(120);
        */

        /* set left-right mode */
        err = sharp_panel_write(sharp, 0x1000, 0x2a);
        if (err < 0) {
                dev_err(panel->dev, "failed to set left-right mode: %d\n", err);
                goto poweroff;
        }

        /* enable command mode */
        err = sharp_panel_write(sharp, 0x1001, 0x01);
        if (err < 0) {
                dev_err(panel->dev, "failed to enable command mode: %d\n", err);
                goto poweroff;
        }

        err = mipi_dsi_dcs_set_pixel_format(sharp->link1, format);
        if (err < 0) {
                dev_err(panel->dev, "failed to set pixel format: %d\n", err);
                goto poweroff;
        }

        /*
         * TODO: The device supports both left-right and even-odd split
         * configurations, but this driver currently supports only the left-
         * right split. To support a different mode a mechanism needs to be
         * put in place to communicate the configuration back to the DSI host
         * controller.
         */
        err = sharp_setup_symmetrical_split(sharp->link1, sharp->link2,
                                            sharp->mode);
        if (err < 0) {
                dev_err(panel->dev, "failed to set up symmetrical split: %d\n",
                        err);
                goto poweroff;
        }

        err = mipi_dsi_dcs_set_display_on(sharp->link1);
        if (err < 0) {
                dev_err(panel->dev, "failed to set display on: %d\n", err);
                goto poweroff;
        }

        sharp->prepared = true;

        /* wait for 6 frames before continuing */
        sharp_wait_frames(sharp, 6);

        return 0;

poweroff:
        regulator_disable(sharp->supply);
        return err;
}

static int sharp_panel_enable(struct drm_panel *panel)
{
        struct sharp_panel *sharp = to_sharp_panel(panel);

        if (sharp->enabled)
                return 0;

        backlight_enable(sharp->backlight);

        sharp->enabled = true;

        return 0;
}

static const struct drm_display_mode default_mode = {
        .clock = 278000,
        .hdisplay = 2560,
        .hsync_start = 2560 + 128,
        .hsync_end = 2560 + 128 + 64,
        .htotal = 2560 + 128 + 64 + 64,
        .vdisplay = 1600,
        .vsync_start = 1600 + 4,
        .vsync_end = 1600 + 4 + 8,
        .vtotal = 1600 + 4 + 8 + 32,
        .vrefresh = 60,
};

static int sharp_panel_get_modes(struct drm_panel *panel)
{
        struct drm_display_mode *mode;

        mode = drm_mode_duplicate(panel->drm, &default_mode);
        if (!mode) {
                dev_err(panel->drm->dev, "failed to add mode %ux%ux@%u\n",
                        default_mode.hdisplay, default_mode.vdisplay,
                        default_mode.vrefresh);
                return -ENOMEM;
        }

        drm_mode_set_name(mode);

        drm_mode_probed_add(panel->connector, mode);

        panel->connector->display_info.width_mm = 217;
        panel->connector->display_info.height_mm = 136;

        return 1;
}

static const struct drm_panel_funcs sharp_panel_funcs = {
        .disable = sharp_panel_disable,
        .unprepare = sharp_panel_unprepare,
        .prepare = sharp_panel_prepare,
        .enable = sharp_panel_enable,
        .get_modes = sharp_panel_get_modes,
};

static const struct of_device_id sharp_of_match[] = {
        { .compatible = "sharp,lq101r1sx01", },
        { }
};
MODULE_DEVICE_TABLE(of, sharp_of_match);

static int sharp_panel_add(struct sharp_panel *sharp)
{
        struct device *dev = &sharp->link1->dev;

        sharp->mode = &default_mode;

        sharp->supply = devm_regulator_get(&sharp->link1->dev, "power");
        if (IS_ERR(sharp->supply))
                return PTR_ERR(sharp->supply);

        sharp->backlight = devm_of_find_backlight(dev);

        if (IS_ERR(sharp->backlight))
                return PTR_ERR(sharp->backlight);

        drm_panel_init(&sharp->base);
        sharp->base.funcs = &sharp_panel_funcs;
        sharp->base.dev = &sharp->link1->dev;

        return drm_panel_add(&sharp->base);
}

static void sharp_panel_del(struct sharp_panel *sharp)
{
        if (sharp->base.dev)
                drm_panel_remove(&sharp->base);

        if (sharp->link2)
                put_device(&sharp->link2->dev);
}

static int sharp_panel_probe(struct mipi_dsi_device *dsi)
{
        struct mipi_dsi_device *secondary = NULL;
        struct sharp_panel *sharp;
        struct device_node *np;
        int err;

        dsi->lanes = 4;
        dsi->format = MIPI_DSI_FMT_RGB888;
        dsi->mode_flags = MIPI_DSI_MODE_LPM;

        /* Find DSI-LINK1 */
        np = of_parse_phandle(dsi->dev.of_node, "link2", 0);
        if (np) {
                secondary = of_find_mipi_dsi_device_by_node(np);
                of_node_put(np);

                if (!secondary)
                        return -EPROBE_DEFER;
        }

        /* register a panel for only the DSI-LINK1 interface */
        if (secondary) {
                sharp = devm_kzalloc(&dsi->dev, sizeof(*sharp), GFP_KERNEL);
                if (!sharp) {
                        put_device(&secondary->dev);
                        return -ENOMEM;
                }

                mipi_dsi_set_drvdata(dsi, sharp);

                sharp->link2 = secondary;
                sharp->link1 = dsi;

                err = sharp_panel_add(sharp);
                if (err < 0) {
                        put_device(&secondary->dev);
                        return err;
                }
        }

        err = mipi_dsi_attach(dsi);
        if (err < 0) {
                if (secondary)
                        sharp_panel_del(sharp);

                return err;
        }

        return 0;
}

static int sharp_panel_remove(struct mipi_dsi_device *dsi)
{
        struct sharp_panel *sharp = mipi_dsi_get_drvdata(dsi);
        int err;

        /* only detach from host for the DSI-LINK2 interface */
        if (!sharp) {
                mipi_dsi_detach(dsi);
                return 0;
        }

        err = sharp_panel_disable(&sharp->base);
        if (err < 0)
                dev_err(&dsi->dev, "failed to disable panel: %d\n", err);

        err = mipi_dsi_detach(dsi);
        if (err < 0)
                dev_err(&dsi->dev, "failed to detach from DSI host: %d\n", err);

        drm_panel_detach(&sharp->base);
        sharp_panel_del(sharp);

        return 0;
}

static void sharp_panel_shutdown(struct mipi_dsi_device *dsi)
{
        struct sharp_panel *sharp = mipi_dsi_get_drvdata(dsi);

        /* nothing to do for DSI-LINK2 */
        if (!sharp)
                return;

        sharp_panel_disable(&sharp->base);
}

static struct mipi_dsi_driver sharp_panel_driver = {
        .driver = {
                .name = "panel-sharp-lq101r1sx01",
                .of_match_table = sharp_of_match,
        },
        .probe = sharp_panel_probe,
        .remove = sharp_panel_remove,
        .shutdown = sharp_panel_shutdown,
};
module_mipi_dsi_driver(sharp_panel_driver);

MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
MODULE_DESCRIPTION("Sharp LQ101R1SX01 panel driver");
MODULE_LICENSE("GPL v2");