// SPDX-License-Identifier: GPL-2.0
/*
 * Arch R Generic MIPI-DSI panel driver
 * Copyright (C) 2025 Arch R Project
 *
 * Based on panel-generic-dsi.c by ROCKNIX (C) 2024
 * Originally based on Rockteck jh057n00900 panel driver
 * Copyright (C) Purism SPC 2019
 *
 * Reads panel configuration from device tree "panel_description" property.
 * Supports any MIPI-DSI panel without recompilation — just change the DTS.
 *
 * panel_description format (array of strings):
 *   G delays=P,R,I,E,Y size=W,H format=rgb888 lanes=4 flags=0xNNN
 *   M clock=KHZ horizontal=H,HFP,HSYNC,HBP vertical=V,VFP,VSYNC,VBP default=1
 *   I dcs=0xCMD data=HEXPARAMS wait=MS
 *   I seq=HEXBYTES wait=MS
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/media-bus-format.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>

#include <video/display_timing.h>
#include <video/mipi_display.h>

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

#define DRIVER_NAME "panel-archr-dsi"

struct archr_panel_delays {
	int prepare;
	int reset;
	int init;
	int enable;
	int ready;
};

struct archr_panel_size {
	int width;
	int height;
};

struct archr_panel_mode {
	int clock;
	int horizontal[5];
	int vertical[5];
	int is_default;
	struct archr_panel_mode *prev;
};

#define DCS_PSEUDO_CMD_SEQ 0x10000
struct archr_panel_init_seq {
	int dcs;
	int len;
	int read;
	int wait;
	u8 *data;
	struct archr_panel_init_seq *link;
};

struct archr_panel {
	struct device *dev;
	struct drm_panel panel;
	struct gpio_desc *enable_gpio;
	struct gpio_desc *reset_gpio;
	struct regulator *vdd;
	struct regulator *iovcc;

	struct archr_panel_delays delays;
	struct archr_panel_size size;
	struct archr_panel_mode *modes;
	struct archr_panel_init_seq *iseq;

	enum drm_panel_orientation orientation;
	bool prepared;
};

static int load_globals(char *data, struct mipi_dsi_device *dsi,
			struct archr_panel *ctx)
{
	struct device *dev = &dsi->dev;
	char *param, *val;

	while (*data) {
		data = next_arg(data, &param, &val);
		if (!val)
			continue;
		if (strcmp(param, "delays") == 0) {
			int delays[] = {0, 5, 1, 25, 120, 50};
			get_options(val, 6, delays);
			ctx->delays.prepare = delays[1];
			ctx->delays.reset   = delays[2];
			ctx->delays.init    = delays[3];
			ctx->delays.enable  = delays[4];
			ctx->delays.ready   = delays[5];
		} else if (strcmp(param, "size") == 0) {
			int size[] = {0, -1, -1};
			get_options(val, 3, size);
			ctx->size.width  = size[1];
			ctx->size.height = size[2];
		} else if (strcmp(param, "format") == 0) {
			if (strcmp(val, "rgb888") == 0)
				dsi->format = MIPI_DSI_FMT_RGB888;
			else if (strcmp(val, "rgb666") == 0)
				dsi->format = MIPI_DSI_FMT_RGB666;
			else if (strcmp(val, "rgb666_packed") == 0)
				dsi->format = MIPI_DSI_FMT_RGB666_PACKED;
			else if (strcmp(val, "rgb565") == 0)
				dsi->format = MIPI_DSI_FMT_RGB565;
			else
				dev_info(dev, "bad format %s\n", val);
		} else if (strcmp(param, "lanes") == 0) {
			if (get_option(&val, &dsi->lanes) == 0)
				dev_info(dev, "bad lanes %s\n", val);
		} else if (strcmp(param, "flags") == 0) {
			int flags;
			if (get_option(&val, &flags) == 0)
				dev_info(dev, "bad flags %s\n", val);
			else
				dsi->mode_flags = flags;
		} else {
			dev_info(dev, "unknown param %s\n", param);
			return -1;
		}
	}
	return 0;
}

static int load_mode(char *data, struct mipi_dsi_device *dsi,
		     struct archr_panel *ctx)
{
	struct device *dev = &dsi->dev;
	struct archr_panel_mode *mode;
	char *param, *val;

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

	while (*data) {
		data = next_arg(data, &param, &val);
		if (!val)
			continue;
		if (strcmp(param, "clock") == 0) {
			if (get_option(&val, &mode->clock) == 0)
				dev_info(dev, "bad clock %s\n", val);
		} else if (strcmp(param, "horizontal") == 0) {
			get_options(val, 5, &mode->horizontal[0]);
		} else if (strcmp(param, "vertical") == 0) {
			get_options(val, 5, &mode->vertical[0]);
		} else if (strcmp(param, "default") == 0) {
			get_option(&val, &mode->is_default);
		} else {
			dev_info(dev, "Mode unhandled %s = %s\n", param, val);
		}
	}

	if ((mode->clock > 5000) && (mode->vertical[1] > 0) &&
	    (mode->horizontal[1] > 0)) {
		mode->prev = ctx->modes;
		ctx->modes = mode;
		dev_dbg(dev, "Mode %d %d %d  %p -> %p\n",
			mode->clock, mode->vertical[1],
			mode->horizontal[1], mode, mode->prev);
		return 0;
	}
	return -1;
}

static int load_init_seq(char *data, struct mipi_dsi_device *dsi,
			 struct archr_panel *ctx)
{
	struct device *dev = &dsi->dev;
	struct archr_panel_init_seq *item;
	char *param, *val;

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

	item->dcs = -1;
	item->len = -1;
	item->read = 0;
	item->wait = 0;

	while (*data) {
		data = next_arg(data, &param, &val);
		if (!val)
			continue;
		if (strcmp(param, "dcs") == 0) {
			item->dcs = simple_strtoul(val, NULL, 16) & 0xFF;
		} else if (strcmp(param, "data") == 0) {
			item->len = (strlen(val)) >> 1;
			item->data = devm_kzalloc(dev, item->len, GFP_KERNEL);
			if (!item->data)
				return -ENOMEM;
			if (hex2bin(item->data, val, item->len) != 0) {
				dev_info(dev, "bad data %s\n", val);
				return -1;
			}
		} else if (strcmp(param, "seq") == 0) {
			item->dcs = DCS_PSEUDO_CMD_SEQ;
			item->len = (strlen(val)) >> 1;
			item->data = devm_kzalloc(dev, item->len, GFP_KERNEL);
			if (!item->data)
				return -ENOMEM;
			if (hex2bin(item->data, val, item->len) != 0) {
				dev_info(dev, "bad seq %s\n", val);
				return -1;
			}
			dev_dbg(dev, "loaded seq len=%d %s\n", item->len, val);
		} else if (strcmp(param, "read") == 0) {
			item->read = simple_strtoul(val, NULL, 16);
		} else if (strcmp(param, "wait") == 0) {
			item->wait = simple_strtoul(val, NULL, 16);
		} else {
			dev_info(dev, "Init unhandled %s = %s\n", param, val);
		}
	}

	if (item->dcs >= 0) {
		item->link = ctx->iseq;
		ctx->iseq = item;
		return 0;
	}

	return -1;
}

static int load_panel_description_line(char *data, struct mipi_dsi_device *dsi,
				       struct archr_panel *ctx)
{
	size_t pos;

	for (pos = 0; data[pos] != 0; pos++) {
		if ((data[pos] == '#') || data[pos] == '\n') {
			data[pos] = 0;
			break;
		}
	}
	if (pos < 2)
		return 0;

	switch (data[0]) {
	case 'G':
		load_globals(data + 1, dsi, ctx);
		break;
	case 'M':
		load_mode(data + 1, dsi, ctx);
		break;
	case 'I':
		load_init_seq(data + 1, dsi, ctx);
		break;
	default:
		dev_info(&dsi->dev, "Unhandled line: %s\n", data);
	}

	return 0;
}

static int load_panel_description(struct mipi_dsi_device *dsi,
				  struct archr_panel *ctx)
{
	struct device *dev = &dsi->dev;
	struct archr_panel_init_seq *rev, *fwd, *tmp;
	const char *line;
	char *buf;
	size_t linescnt, i;
	int ret;

	linescnt = of_property_count_strings(dev->of_node, "panel_description");
	if (linescnt < 1) {
		dev_err(dev, "failed to read panel_description from device tree (%ld)\n",
			linescnt);
		return -EINVAL;
	}

	for (i = 0; i < linescnt; i++) {
		ret = of_property_read_string_index(dev->of_node,
						    "panel_description",
						    i, &line);
		if (ret < 0) {
			dev_err(dev, "failed to read panel_description[%ld]: %d\n",
				i, ret);
			return ret;
		}
		buf = kstrdup(line, GFP_KERNEL);
		if (!buf)
			return -ENOMEM;

		dev_dbg(dev, "desc[%ld]: %s\n", i, line);
		load_panel_description_line(buf, dsi, ctx);
		kfree(buf);
	}

	/* Reverse init sequence list (DTS order → execution order) */
	rev = ctx->iseq;
	fwd = NULL;
	while (rev) {
		tmp = rev;
		rev = tmp->link;
		tmp->link = fwd;
		fwd = tmp;
	}
	ctx->iseq = fwd;

	return 0;
}

static inline struct archr_panel *panel_to_archr(struct drm_panel *panel)
{
	return container_of(panel, struct archr_panel, panel);
}

static int archr_panel_init_sequence(struct archr_panel *ctx)
{
	struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
	struct device *dev = ctx->dev;
	struct archr_panel_init_seq *iseq = ctx->iseq;
	int ret;

	while (iseq) {
		if (iseq->read > 0) {
			u8 readbuf[8];
			if (iseq->read > 8)
				iseq->read = 8;
			ret = mipi_dsi_generic_read(dsi, iseq->data,
						    iseq->len, &readbuf[0],
						    iseq->read);
			if (ret < 0) {
				dev_err(dev, "failed to read: %d\n", ret);
			} else {
				int j;
				for (j = 0; j < ret; j++)
					dev_info(dev, "read[%d]: %02x\n",
						 j, readbuf[j]);
			}
		} else if (iseq->dcs == DCS_PSEUDO_CMD_SEQ) {
			ret = mipi_dsi_dcs_write_buffer(dsi, iseq->data,
							iseq->len);
			dev_dbg(dev, "iseq %px len=%d -> %d\n",
				(void *)iseq, iseq->len, ret);
		} else {
			ret = mipi_dsi_dcs_write(dsi, iseq->dcs, iseq->data,
						 iseq->len);
			dev_dbg(dev, "iseq %02x len=%d -> %d\n",
				iseq->dcs, iseq->len, ret);
		}
		if (iseq->wait)
			msleep(iseq->wait);
		iseq = iseq->link;
	}

	dev_dbg(dev, "Panel init sequence done\n");
	return 0;
}

static int archr_panel_unprepare(struct drm_panel *panel)
{
	struct archr_panel *ctx = panel_to_archr(panel);
	struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
	int ret;

	if (!ctx->prepared)
		return 0;

	ret = mipi_dsi_dcs_set_display_off(dsi);
	if (ret < 0)
		dev_err(ctx->dev, "failed to set display off: %d\n", ret);

	ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
	if (ret < 0) {
		dev_err(ctx->dev, "failed to enter sleep mode: %d\n", ret);
		return ret;
	}

	if (ctx->enable_gpio)
		gpiod_set_value_cansleep(ctx->enable_gpio, 0);
	gpiod_set_value_cansleep(ctx->reset_gpio, 1);

	regulator_disable(ctx->iovcc);
	regulator_disable(ctx->vdd);

	gpiod_set_value_cansleep(ctx->reset_gpio, 1);

	ctx->prepared = false;
	return 0;
}

static int archr_panel_prepare(struct drm_panel *panel)
{
	struct archr_panel *ctx = panel_to_archr(panel);
	int ret;

	if (ctx->prepared)
		return 0;

	ret = regulator_enable(ctx->vdd);
	if (ret < 0) {
		dev_err(ctx->dev, "Failed to enable vdd supply: %d\n", ret);
		return ret;
	}

	ret = regulator_enable(ctx->iovcc);
	if (ret < 0) {
		dev_err(ctx->dev, "Failed to enable iovcc supply: %d\n", ret);
		goto disable_vdd;
	}

	if (ctx->enable_gpio)
		gpiod_set_value_cansleep(ctx->enable_gpio, 1);
	msleep(ctx->delays.prepare);

	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
	msleep(ctx->delays.reset);
	gpiod_set_value_cansleep(ctx->reset_gpio, 0);

	msleep(ctx->delays.init);

	ret = archr_panel_init_sequence(ctx);
	if (ret < 0) {
		dev_err(ctx->dev, "Panel init sequence failed: %d\n", ret);
		goto disable_iovcc;
	}

	ret = mipi_dsi_dcs_set_display_on(
		to_mipi_dsi_device(ctx->dev));
	if (ret < 0) {
		dev_err(ctx->dev, "Failed to set display on: %d\n", ret);
		goto disable_iovcc;
	}

	ret = mipi_dsi_dcs_exit_sleep_mode(
		to_mipi_dsi_device(ctx->dev));
	if (ret < 0) {
		dev_err(ctx->dev, "Failed to exit sleep mode: %d\n", ret);
		goto disable_iovcc;
	}

	msleep(ctx->delays.enable);

	ctx->prepared = true;
	return 0;

disable_iovcc:
	regulator_disable(ctx->iovcc);
disable_vdd:
	regulator_disable(ctx->vdd);
	return ret;
}

static const struct drm_display_mode mode_template = { };

static int archr_panel_get_modes(struct drm_panel *panel,
				 struct drm_connector *connector)
{
	struct archr_panel *ctx = panel_to_archr(panel);
	struct drm_display_mode mode_tmp;
	struct drm_display_mode *mode;
	struct archr_panel_mode *genmode = ctx->modes;

	while (genmode) {
		dev_dbg(ctx->dev, "mode %d %dx%d\n",
			genmode->clock, genmode->horizontal[1],
			genmode->vertical[1]);

		mode_tmp = mode_template;

		mode_tmp.clock       = genmode->clock;

		mode_tmp.hdisplay    = genmode->horizontal[1];
		mode_tmp.hsync_start = mode_tmp.hdisplay + genmode->horizontal[2];
		mode_tmp.hsync_end   = mode_tmp.hsync_start + genmode->horizontal[3];
		mode_tmp.htotal      = mode_tmp.hsync_end + genmode->horizontal[4];

		mode_tmp.vdisplay    = genmode->vertical[1];
		mode_tmp.vsync_start = mode_tmp.vdisplay + genmode->vertical[2];
		mode_tmp.vsync_end   = mode_tmp.vsync_start + genmode->vertical[3];
		mode_tmp.vtotal      = mode_tmp.vsync_end + genmode->vertical[4];

		mode_tmp.width_mm    = ctx->size.width;
		mode_tmp.height_mm   = ctx->size.height;

		mode_tmp.flags       = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC;

		mode = drm_mode_duplicate(connector->dev, &mode_tmp);
		if (!mode) {
			dev_err(ctx->dev, "Failed to add mode\n");
			return -ENOMEM;
		}
		drm_mode_set_name(mode);

		mode->type = DRM_MODE_TYPE_DRIVER;
		if (genmode->is_default)
			mode->type |= DRM_MODE_TYPE_PREFERRED;

		drm_mode_probed_add(connector, mode);

		genmode = genmode->prev;
	}

	connector->display_info.width_mm = ctx->size.width;
	connector->display_info.height_mm = ctx->size.height;

	drm_connector_set_panel_orientation(connector, ctx->orientation);

	return 1;
}

static enum drm_panel_orientation archr_panel_get_orientation(
	struct drm_panel *panel)
{
	struct archr_panel *ctx = panel_to_archr(panel);
	return ctx->orientation;
}

static const struct drm_panel_funcs archr_panel_funcs = {
	.unprepare       = archr_panel_unprepare,
	.prepare         = archr_panel_prepare,
	.get_modes       = archr_panel_get_modes,
	.get_orientation = archr_panel_get_orientation,
};

static int archr_panel_probe(struct mipi_dsi_device *dsi)
{
	struct device *dev = &dsi->dev;
	struct archr_panel *ctx;
	int ret;

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

	ctx->enable_gpio = devm_gpiod_get_optional(dev, "enable",
						    GPIOD_OUT_LOW);
	if (IS_ERR(ctx->enable_gpio)) {
		dev_err(dev, "cannot get enable gpio\n");
		ctx->enable_gpio = NULL;
	}

	ctx->reset_gpio = devm_gpiod_get_optional(dev, "reset",
						   GPIOD_OUT_LOW);
	if (IS_ERR(ctx->reset_gpio)) {
		dev_err(dev, "cannot get reset gpio\n");
		return PTR_ERR(ctx->reset_gpio);
	}

	ctx->vdd = devm_regulator_get(dev, "vdd");
	if (IS_ERR(ctx->vdd)) {
		ret = PTR_ERR(ctx->vdd);
		if (ret != -EPROBE_DEFER)
			dev_err(dev, "Failed to request vdd regulator: %d\n",
				ret);
		return ret;
	}

	ctx->iovcc = devm_regulator_get(dev, "iovcc");
	if (IS_ERR(ctx->iovcc)) {
		ret = PTR_ERR(ctx->iovcc);
		if (ret != -EPROBE_DEFER)
			dev_err(dev, "Failed to request iovcc regulator: %d\n",
				ret);
		return ret;
	}

	ret = of_drm_get_panel_orientation(dev->of_node, &ctx->orientation);
	if (ret < 0) {
		dev_err(dev, "%pOF: failed to get orientation %d\n",
			dev->of_node, ret);
		return ret;
	}

	mipi_dsi_set_drvdata(dsi, ctx);

	ctx->dev = dev;

	/* Defaults (overridden by G line in panel_description) */
	dsi->lanes = 1;
	dsi->format = MIPI_DSI_FMT_RGB888;
	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
			  MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_NO_EOT_PACKET |
			  MIPI_DSI_CLOCK_NON_CONTINUOUS;

	ret = load_panel_description(dsi, ctx);
	if (ret < 0) {
		dev_err(dev, "Failed to load panel description\n");
		return ret;
	}

	dev_info(dev, "lanes %d, format %d, mode %lx\n",
		 dsi->lanes, dsi->format, dsi->mode_flags);

	drm_panel_init(&ctx->panel, &dsi->dev, &archr_panel_funcs,
		       DRM_MODE_CONNECTOR_DSI);

	ret = drm_panel_of_backlight(&ctx->panel);
	if (ret)
		return ret;

	drm_panel_add(&ctx->panel);

	ret = mipi_dsi_attach(dsi);
	if (ret < 0) {
		dev_err(dev, "mipi_dsi_attach failed: %d\n", ret);
		drm_panel_remove(&ctx->panel);
		return ret;
	}

	return 0;
}

static void archr_panel_shutdown(struct mipi_dsi_device *dsi)
{
	struct archr_panel *ctx = mipi_dsi_get_drvdata(dsi);

	drm_panel_unprepare(&ctx->panel);
	drm_panel_disable(&ctx->panel);
}

static void archr_panel_remove(struct mipi_dsi_device *dsi)
{
	struct archr_panel *ctx = mipi_dsi_get_drvdata(dsi);
	int ret;

	archr_panel_shutdown(dsi);

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

	drm_panel_remove(&ctx->panel);
}

static const struct of_device_id archr_panel_of_match[] = {
	{ .compatible = "archr,generic-dsi" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, archr_panel_of_match);

static struct mipi_dsi_driver archr_panel_driver = {
	.driver = {
		.name = DRIVER_NAME,
		.of_match_table = archr_panel_of_match,
	},
	.probe    = archr_panel_probe,
	.remove   = archr_panel_remove,
	.shutdown = archr_panel_shutdown,
};
module_mipi_dsi_driver(archr_panel_driver);

MODULE_AUTHOR("Arch R Project");
MODULE_DESCRIPTION("Arch R Generic MIPI-DSI panel driver");
MODULE_LICENSE("GPL v2");