// SPDX-License-Identifier: GPL-2.0
/*
 * Panel driver for the ARM Versatile family reference designs from
 * ARM Limited.
 *
 * Author:
 * Linus Walleij <linus.wallei@linaro.org>
 *
 * On the Versatile AB, these panels come mounted on daughterboards
 * named "IB1" or "IB2" (Interface Board 1 & 2 respectively.) They
 * are documented in ARM DUI 0225D Appendix C and D. These daughter
 * boards support TFT display panels.
 *
 * - The IB1 is a passive board where the display connector defines a
 *   few wires for encoding the display type for autodetection,
 *   suitable display settings can then be looked up from this setting.
 *   The magic bits can be read out from the system controller.
 *
 * - The IB2 is a more complex board intended for GSM phone development
 *   with some logic and a control register, which needs to be accessed
 *   and the board display needs to be turned on explicitly.
 *
 * On the Versatile PB, a special CLCD adaptor board is available
 * supporting the same displays as the Versatile AB, plus one more
 * Epson QCIF display.
 *
 */

#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#include <video/of_videomode.h>
#include <video/videomode.h>

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

/*
 * This configuration register in the Versatile and RealView
 * family is uniformly present but appears more and more
 * unutilized starting with the RealView series.
 */
#define SYS_CLCD                        0x50

/* The Versatile can detect the connected panel type */
#define SYS_CLCD_CLCDID_MASK            (BIT(8)|BIT(9)|BIT(10)|BIT(11)|BIT(12))
#define SYS_CLCD_ID_SANYO_3_8           (0x00 << 8)
#define SYS_CLCD_ID_SHARP_8_4           (0x01 << 8)
#define SYS_CLCD_ID_EPSON_2_2           (0x02 << 8)
#define SYS_CLCD_ID_SANYO_2_5           (0x07 << 8)
#define SYS_CLCD_ID_VGA                 (0x1f << 8)

/* IB2 control register for the Versatile daughterboard */
#define IB2_CTRL                        0x00
#define IB2_CTRL_LCD_SD                 BIT(1) /* 1 = shut down LCD */
#define IB2_CTRL_LCD_BL_ON              BIT(0)
#define IB2_CTRL_LCD_MASK               (BIT(0)|BIT(1))

/**
 * struct versatile_panel_type - lookup struct for the supported panels
 */
struct versatile_panel_type {
        /**
         * @name: the name of this panel
         */
        const char *name;
        /**
         * @magic: the magic value from the detection register
         */
        u32 magic;
        /**
         * @mode: the DRM display mode for this panel
         */
        struct drm_display_mode mode;
        /**
         * @bus_flags: the DRM bus flags for this panel e.g. inverted clock
         */
        u32 bus_flags;
        /**
         * @width_mm: the panel width in mm
         */
        u32 width_mm;
        /**
         * @height_mm: the panel height in mm
         */
        u32 height_mm;
        /**
         * @ib2: the panel may be connected on an IB2 daughterboard
         */
        bool ib2;
};

/**
 * struct versatile_panel - state container for the Versatile panels
 */
struct versatile_panel {
        /**
         * @dev: the container device
         */
        struct device *dev;
        /**
         * @panel: the DRM panel instance for this device
         */
        struct drm_panel panel;
        /**
         * @panel_type: the Versatile panel type as detected
         */
        const struct versatile_panel_type *panel_type;
        /**
         * @map: map to the parent syscon where the main register reside
         */
        struct regmap *map;
        /**
         * @ib2_map: map to the IB2 syscon, if applicable
         */
        struct regmap *ib2_map;
};

static const struct versatile_panel_type versatile_panels[] = {
        /*
         * Sanyo TM38QV67A02A - 3.8 inch QVGA (320x240) Color TFT
         * found on the Versatile AB IB1 connector or the Versatile
         * PB adaptor board connector.
         */
        {
                .name = "Sanyo TM38QV67A02A",
                .magic = SYS_CLCD_ID_SANYO_3_8,
                .width_mm = 79,
                .height_mm = 54,
                .mode = {
                        .clock = 10000,
                        .hdisplay = 320,
                        .hsync_start = 320 + 6,
                        .hsync_end = 320 + 6 + 6,
                        .htotal = 320 + 6 + 6 + 6,
                        .vdisplay = 240,
                        .vsync_start = 240 + 5,
                        .vsync_end = 240 + 5 + 6,
                        .vtotal = 240 + 5 + 6 + 5,
                        .flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC,
                },
        },
        /*
         * Sharp LQ084V1DG21 640x480 VGA Color TFT module
         * found on the Versatile AB IB1 connector or the Versatile
         * PB adaptor board connector.
         */
        {
                .name = "Sharp LQ084V1DG21",
                .magic = SYS_CLCD_ID_SHARP_8_4,
                .width_mm = 171,
                .height_mm = 130,
                .mode = {
                        .clock = 25000,
                        .hdisplay = 640,
                        .hsync_start = 640 + 24,
                        .hsync_end = 640 + 24 + 96,
                        .htotal = 640 + 24 + 96 + 24,
                        .vdisplay = 480,
                        .vsync_start = 480 + 11,
                        .vsync_end = 480 + 11 + 2,
                        .vtotal = 480 + 11 + 2 + 32,
                        .flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC,
                },
        },
        /*
         * Epson L2F50113T00 - 2.2 inch QCIF 176x220 Color TFT
         * found on the Versatile PB adaptor board connector.
         */
        {
                .name = "Epson L2F50113T00",
                .magic = SYS_CLCD_ID_EPSON_2_2,
                .width_mm = 34,
                .height_mm = 45,
                .mode = {
                        .clock = 62500,
                        .hdisplay = 176,
                        .hsync_start = 176 + 2,
                        .hsync_end = 176 + 2 + 3,
                        .htotal = 176 + 2 + 3 + 3,
                        .vdisplay = 220,
                        .vsync_start = 220 + 0,
                        .vsync_end = 220 + 0 + 2,
                        .vtotal = 220 + 0 + 2 + 1,
                        .flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC,
                },
                .bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE,
        },
        /*
         * Sanyo ALR252RGT 240x320 portrait display found on the
         * Versatile AB IB2 daughterboard for GSM prototyping.
         */
        {
                .name = "Sanyo ALR252RGT",
                .magic = SYS_CLCD_ID_SANYO_2_5,
                .width_mm = 37,
                .height_mm = 50,
                .mode = {
                        .clock = 5400,
                        .hdisplay = 240,
                        .hsync_start = 240 + 10,
                        .hsync_end = 240 + 10 + 10,
                        .htotal = 240 + 10 + 10 + 20,
                        .vdisplay = 320,
                        .vsync_start = 320 + 2,
                        .vsync_end = 320 + 2 + 2,
                        .vtotal = 320 + 2 + 2 + 2,
                        .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
                },
                .bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE,
                .ib2 = true,
        },
};

static inline struct versatile_panel *
to_versatile_panel(struct drm_panel *panel)
{
        return container_of(panel, struct versatile_panel, panel);
}

static int versatile_panel_disable(struct drm_panel *panel)
{
        struct versatile_panel *vpanel = to_versatile_panel(panel);

        /* If we're on an IB2 daughterboard, turn off display */
        if (vpanel->ib2_map) {
                dev_dbg(vpanel->dev, "disable IB2 display\n");
                regmap_update_bits(vpanel->ib2_map,
                                   IB2_CTRL,
                                   IB2_CTRL_LCD_MASK,
                                   IB2_CTRL_LCD_SD);
        }

        return 0;
}

static int versatile_panel_enable(struct drm_panel *panel)
{
        struct versatile_panel *vpanel = to_versatile_panel(panel);

        /* If we're on an IB2 daughterboard, turn on display */
        if (vpanel->ib2_map) {
                dev_dbg(vpanel->dev, "enable IB2 display\n");
                regmap_update_bits(vpanel->ib2_map,
                                   IB2_CTRL,
                                   IB2_CTRL_LCD_MASK,
                                   IB2_CTRL_LCD_BL_ON);
        }

        return 0;
}

static int versatile_panel_get_modes(struct drm_panel *panel,
                                     struct drm_connector *connector)
{
        struct versatile_panel *vpanel = to_versatile_panel(panel);
        struct drm_display_mode *mode;

        connector->display_info.width_mm = vpanel->panel_type->width_mm;
        connector->display_info.height_mm = vpanel->panel_type->height_mm;
        connector->display_info.bus_flags = vpanel->panel_type->bus_flags;

        mode = drm_mode_duplicate(connector->dev, &vpanel->panel_type->mode);
        drm_mode_set_name(mode);
        mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;

        mode->width_mm = vpanel->panel_type->width_mm;
        mode->height_mm = vpanel->panel_type->height_mm;
        drm_mode_probed_add(connector, mode);

        return 1;
}

static const struct drm_panel_funcs versatile_panel_drm_funcs = {
        .disable = versatile_panel_disable,
        .enable = versatile_panel_enable,
        .get_modes = versatile_panel_get_modes,
};

static int versatile_panel_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct versatile_panel *vpanel;
        struct device *parent;
        struct regmap *map;
        int ret;
        u32 val;
        int i;

        parent = dev->parent;
        if (!parent) {
                dev_err(dev, "no parent for versatile panel\n");
                return -ENODEV;
        }
        map = syscon_node_to_regmap(parent->of_node);
        if (IS_ERR(map)) {
                dev_err(dev, "no regmap for versatile panel parent\n");
                return PTR_ERR(map);
        }

        vpanel = devm_kzalloc(dev, sizeof(*vpanel), GFP_KERNEL);
        if (!vpanel)
                return -ENOMEM;

        ret = regmap_read(map, SYS_CLCD, &val);
        if (ret) {
                dev_err(dev, "cannot access syscon regs\n");
                return ret;
        }

        val &= SYS_CLCD_CLCDID_MASK;

        for (i = 0; i < ARRAY_SIZE(versatile_panels); i++) {
                const struct versatile_panel_type *pt;

                pt = &versatile_panels[i];
                if (pt->magic == val) {
                        vpanel->panel_type = pt;
                        break;
                }
        }

        /* No panel detected or VGA, let's leave this show */
        if (i == ARRAY_SIZE(versatile_panels)) {
                dev_info(dev, "no panel detected\n");
                return -ENODEV;
        }

        dev_info(dev, "detected: %s\n", vpanel->panel_type->name);
        vpanel->dev = dev;
        vpanel->map = map;

        /* Check if the panel is mounted on an IB2 daughterboard */
        if (vpanel->panel_type->ib2) {
                vpanel->ib2_map = syscon_regmap_lookup_by_compatible(
                        "arm,versatile-ib2-syscon");
                if (IS_ERR(vpanel->ib2_map))
                        vpanel->ib2_map = NULL;
                else
                        dev_info(dev, "panel mounted on IB2 daughterboard\n");
        }

        drm_panel_init(&vpanel->panel, dev, &versatile_panel_drm_funcs,
                       DRM_MODE_CONNECTOR_DPI);

        drm_panel_add(&vpanel->panel);

        return 0;
}

static const struct of_device_id versatile_panel_match[] = {
        { .compatible = "arm,versatile-tft-panel", },
        {},
};
MODULE_DEVICE_TABLE(of, versatile_panel_match);

static struct platform_driver versatile_panel_driver = {
        .probe          = versatile_panel_probe,
        .driver         = {
                .name   = "versatile-tft-panel",
                .of_match_table = versatile_panel_match,
        },
};
module_platform_driver(versatile_panel_driver);

MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
MODULE_DESCRIPTION("ARM Versatile panel driver");
MODULE_LICENSE("GPL v2");