text: /*
   * Copyright (C) 2016 InforceComputing
   * Author: Vinay Simha BN <simhavcs@gmail.com>
   *
   * Copyright (C) 2016 Linaro Ltd
   * Author: Sumit Semwal <sumit.semwal@linaro.org>
   *
   * From internet archives, the panel for Nexus 7 2nd Gen, 2013 model is a
   * JDI model LT070ME05000, and its data sheet is at:
   * http://panelone.net/en/7-0-inch/JDI_LT070ME05000_7.0_inch-datasheet
   *
   * 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.
   *
   * This program is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  #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>
  
  static const char * const regulator_names[] = {
  	"vddp",
  	"iovcc"
  };
  
  struct jdi_panel {
  	struct drm_panel base;
  	struct mipi_dsi_device *dsi;
  
  	struct regulator_bulk_data supplies[ARRAY_SIZE(regulator_names)];
  
  	struct gpio_desc *enable_gpio;
  	struct gpio_desc *reset_gpio;
  	struct gpio_desc *dcdc_en_gpio;
  	struct backlight_device *backlight;
  
  	bool prepared;
  	bool enabled;
  
  	const struct drm_display_mode *mode;
  };
  
  static inline struct jdi_panel *to_jdi_panel(struct drm_panel *panel)
  {
  	return container_of(panel, struct jdi_panel, base);
  }
  
  static int jdi_panel_init(struct jdi_panel *jdi)
  {
  	struct mipi_dsi_device *dsi = jdi->dsi;
  	struct device *dev = &jdi->dsi->dev;
  	int ret;
  
  	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
  
  	ret = mipi_dsi_dcs_soft_reset(dsi);
  	if (ret < 0)
  		return ret;
  
  	usleep_range(10000, 20000);
  
  	ret = mipi_dsi_dcs_set_pixel_format(dsi, MIPI_DCS_PIXEL_FMT_24BIT << 4);
  	if (ret < 0) {
  		dev_err(dev, "failed to set pixel format: %d\n", ret);
  		return ret;
  	}
  
  	ret = mipi_dsi_dcs_set_column_address(dsi, 0, jdi->mode->hdisplay - 1);
  	if (ret < 0) {
  		dev_err(dev, "failed to set column address: %d\n", ret);
  		return ret;
  	}
  
  	ret = mipi_dsi_dcs_set_page_address(dsi, 0, jdi->mode->vdisplay - 1);
  	if (ret < 0) {
  		dev_err(dev, "failed to set page address: %d\n", ret);
  		return ret;
  	}
  
  	/*
  	 * BIT(5) BCTRL = 1 Backlight Control Block On, Brightness registers
  	 *                  are active
  	 * BIT(3) BL = 1    Backlight Control On
  	 * BIT(2) DD = 0    Display Dimming is Off
  	 */
  	ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_WRITE_CONTROL_DISPLAY,
  				 (u8[]){ 0x24 }, 1);
  	if (ret < 0) {
  		dev_err(dev, "failed to write control display: %d\n", ret);
  		return ret;
  	}
  
  	/* CABC off */
  	ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_WRITE_POWER_SAVE,
  				 (u8[]){ 0x00 }, 1);
  	if (ret < 0) {
  		dev_err(dev, "failed to set cabc off: %d\n", ret);
  		return ret;
  	}
  
  	ret = mipi_dsi_dcs_exit_sleep_mode(dsi);
  	if (ret < 0) {
  		dev_err(dev, "failed to set exit sleep mode: %d\n", ret);
  		return ret;
  	}
  
  	msleep(120);
  
  	ret = mipi_dsi_generic_write(dsi, (u8[]){0xB0, 0x00}, 2);
  	if (ret < 0) {
  		dev_err(dev, "failed to set mcap: %d\n", ret);
  		return ret;
  	}
  
  	mdelay(10);
  
  	/* Interface setting, video mode */
  	ret = mipi_dsi_generic_write(dsi, (u8[])
  				     {0xB3, 0x26, 0x08, 0x00, 0x20, 0x00}, 6);
  	if (ret < 0) {
  		dev_err(dev, "failed to set display interface setting: %d\n"
  			, ret);
  		return ret;
  	}
  
  	mdelay(20);
  
  	ret = mipi_dsi_generic_write(dsi, (u8[]){0xB0, 0x03}, 2);
  	if (ret < 0) {
  		dev_err(dev, "failed to set default values for mcap: %d\n"
  			, ret);
  		return ret;
  	}
  
  	return 0;
  }
  
  static int jdi_panel_on(struct jdi_panel *jdi)
  {
  	struct mipi_dsi_device *dsi = jdi->dsi;
  	struct device *dev = &jdi->dsi->dev;
  	int ret;
  
  	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
  
  	ret = mipi_dsi_dcs_set_display_on(dsi);
  	if (ret < 0)
  		dev_err(dev, "failed to set display on: %d\n", ret);
  
  	return ret;
  }
  
  static void jdi_panel_off(struct jdi_panel *jdi)
  {
  	struct mipi_dsi_device *dsi = jdi->dsi;
  	struct device *dev = &jdi->dsi->dev;
  	int ret;
  
  	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
  
  	ret = mipi_dsi_dcs_set_display_off(dsi);
  	if (ret < 0)
  		dev_err(dev, "failed to set display off: %d\n", ret);
  
  	ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
  	if (ret < 0)
  		dev_err(dev, "failed to enter sleep mode: %d\n", ret);
  
  	msleep(100);
  }
  
  static int jdi_panel_disable(struct drm_panel *panel)
  {
  	struct jdi_panel *jdi = to_jdi_panel(panel);
  
  	if (!jdi->enabled)
  		return 0;
  
  	backlight_disable(jdi->backlight);
  
  	jdi->enabled = false;
  
  	return 0;
  }
  
  static int jdi_panel_unprepare(struct drm_panel *panel)
  {
  	struct jdi_panel *jdi = to_jdi_panel(panel);
  	struct device *dev = &jdi->dsi->dev;
  	int ret;
  
  	if (!jdi->prepared)
  		return 0;
  
  	jdi_panel_off(jdi);
  
  	ret = regulator_bulk_disable(ARRAY_SIZE(jdi->supplies), jdi->supplies);
  	if (ret < 0)
  		dev_err(dev, "regulator disable failed, %d\n", ret);
  
  	gpiod_set_value(jdi->enable_gpio, 0);
  
  	gpiod_set_value(jdi->reset_gpio, 1);
  
  	gpiod_set_value(jdi->dcdc_en_gpio, 0);
  
  	jdi->prepared = false;
  
  	return 0;
  }
  
  static int jdi_panel_prepare(struct drm_panel *panel)
  {
  	struct jdi_panel *jdi = to_jdi_panel(panel);
  	struct device *dev = &jdi->dsi->dev;
  	int ret;
  
  	if (jdi->prepared)
  		return 0;
  
  	ret = regulator_bulk_enable(ARRAY_SIZE(jdi->supplies), jdi->supplies);
  	if (ret < 0) {
  		dev_err(dev, "regulator enable failed, %d\n", ret);
  		return ret;
  	}
  
  	msleep(20);
  
  	gpiod_set_value(jdi->dcdc_en_gpio, 1);
  	usleep_range(10, 20);
  
  	gpiod_set_value(jdi->reset_gpio, 0);
  	usleep_range(10, 20);
  
  	gpiod_set_value(jdi->enable_gpio, 1);
  	usleep_range(10, 20);
  
  	ret = jdi_panel_init(jdi);
  	if (ret < 0) {
  		dev_err(dev, "failed to init panel: %d\n", ret);
  		goto poweroff;
  	}
  
  	ret = jdi_panel_on(jdi);
  	if (ret < 0) {
  		dev_err(dev, "failed to set panel on: %d\n", ret);
  		goto poweroff;
  	}
  
  	jdi->prepared = true;
  
  	return 0;
  
  poweroff:
  	ret = regulator_bulk_disable(ARRAY_SIZE(jdi->supplies), jdi->supplies);
  	if (ret < 0)
  		dev_err(dev, "regulator disable failed, %d\n", ret);
  
  	gpiod_set_value(jdi->enable_gpio, 0);
  
  	gpiod_set_value(jdi->reset_gpio, 1);
  
  	gpiod_set_value(jdi->dcdc_en_gpio, 0);
  
  	return ret;
  }
  
  static int jdi_panel_enable(struct drm_panel *panel)
  {
  	struct jdi_panel *jdi = to_jdi_panel(panel);
  
  	if (jdi->enabled)
  		return 0;
  
  	backlight_enable(jdi->backlight);
  
  	jdi->enabled = true;
  
  	return 0;
  }
  
  static const struct drm_display_mode default_mode = {
  		.clock = 155493,
  		.hdisplay = 1200,
  		.hsync_start = 1200 + 48,
  		.hsync_end = 1200 + 48 + 32,
  		.htotal = 1200 + 48 + 32 + 60,
  		.vdisplay = 1920,
  		.vsync_start = 1920 + 3,
  		.vsync_end = 1920 + 3 + 5,
  		.vtotal = 1920 + 3 + 5 + 6,
  		.vrefresh = 60,
  		.flags = 0,
  };
  
  static int jdi_panel_get_modes(struct drm_panel *panel)
  {
  	struct drm_display_mode *mode;
  	struct jdi_panel *jdi = to_jdi_panel(panel);
  	struct device *dev = &jdi->dsi->dev;
  
  	mode = drm_mode_duplicate(panel->drm, &default_mode);
  	if (!mode) {
  		dev_err(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 = 95;
  	panel->connector->display_info.height_mm = 151;
  
  	return 1;
  }
  
  static int dsi_dcs_bl_get_brightness(struct backlight_device *bl)
  {
  	struct mipi_dsi_device *dsi = bl_get_data(bl);
  	int ret;
  	u16 brightness = bl->props.brightness;
  
  	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
  
  	ret = mipi_dsi_dcs_get_display_brightness(dsi, &brightness);
  	if (ret < 0)
  		return ret;
  
  	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
  
  	return brightness & 0xff;
  }
  
  static int dsi_dcs_bl_update_status(struct backlight_device *bl)
  {
  	struct mipi_dsi_device *dsi = bl_get_data(bl);
  	int ret;
  
  	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
  
  	ret = mipi_dsi_dcs_set_display_brightness(dsi, bl->props.brightness);
  	if (ret < 0)
  		return ret;
  
  	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
  
  	return 0;
  }
  
  static const struct backlight_ops dsi_bl_ops = {
  	.update_status = dsi_dcs_bl_update_status,
  	.get_brightness = dsi_dcs_bl_get_brightness,
  };
  
  static struct backlight_device *
  drm_panel_create_dsi_backlight(struct mipi_dsi_device *dsi)
  {
  	struct device *dev = &dsi->dev;
  	struct backlight_properties props;
  
  	memset(&props, 0, sizeof(props));
  	props.type = BACKLIGHT_RAW;
  	props.brightness = 255;
  	props.max_brightness = 255;
  
  	return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
  					      &dsi_bl_ops, &props);
  }
  
  static const struct drm_panel_funcs jdi_panel_funcs = {
  	.disable = jdi_panel_disable,
  	.unprepare = jdi_panel_unprepare,
  	.prepare = jdi_panel_prepare,
  	.enable = jdi_panel_enable,
  	.get_modes = jdi_panel_get_modes,
  };
  
  static const struct of_device_id jdi_of_match[] = {
  	{ .compatible = "jdi,lt070me05000", },
  	{ }
  };
  MODULE_DEVICE_TABLE(of, jdi_of_match);
  
  static int jdi_panel_add(struct jdi_panel *jdi)
  {
  	struct device *dev = &jdi->dsi->dev;
  	int ret;
  	unsigned int i;
  
  	jdi->mode = &default_mode;
  
  	for (i = 0; i < ARRAY_SIZE(jdi->supplies); i++)
  		jdi->supplies[i].supply = regulator_names[i];
  
  	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(jdi->supplies),
  				      jdi->supplies);
  	if (ret < 0) {
  		dev_err(dev, "failed to init regulator, ret=%d\n", ret);
  		return ret;
  	}
  
  	jdi->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
  	if (IS_ERR(jdi->enable_gpio)) {
  		ret = PTR_ERR(jdi->enable_gpio);
  		dev_err(dev, "cannot get enable-gpio %d\n", ret);
  		return ret;
  	}
  
  	jdi->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
  	if (IS_ERR(jdi->reset_gpio)) {
  		ret = PTR_ERR(jdi->reset_gpio);
  		dev_err(dev, "cannot get reset-gpios %d\n", ret);
  		return ret;
  	}
  
  	jdi->dcdc_en_gpio = devm_gpiod_get(dev, "dcdc-en", GPIOD_OUT_LOW);
  	if (IS_ERR(jdi->dcdc_en_gpio)) {
  		ret = PTR_ERR(jdi->dcdc_en_gpio);
  		dev_err(dev, "cannot get dcdc-en-gpio %d\n", ret);
  		return ret;
  	}
  
  	jdi->backlight = drm_panel_create_dsi_backlight(jdi->dsi);
  	if (IS_ERR(jdi->backlight)) {
  		ret = PTR_ERR(jdi->backlight);
  		dev_err(dev, "failed to register backlight %d\n", ret);
  		return ret;
  	}
  
  	drm_panel_init(&jdi->base);
  	jdi->base.funcs = &jdi_panel_funcs;
  	jdi->base.dev = &jdi->dsi->dev;
  
  	ret = drm_panel_add(&jdi->base);
  
  	return ret;
  }
  
  static void jdi_panel_del(struct jdi_panel *jdi)
  {
  	if (jdi->base.dev)
  		drm_panel_remove(&jdi->base);
  }
  
  static int jdi_panel_probe(struct mipi_dsi_device *dsi)
  {
  	struct jdi_panel *jdi;
  	int ret;
  
  	dsi->lanes = 4;
  	dsi->format = MIPI_DSI_FMT_RGB888;
  	dsi->mode_flags =  MIPI_DSI_MODE_VIDEO_HSE | MIPI_DSI_MODE_VIDEO |
  			   MIPI_DSI_CLOCK_NON_CONTINUOUS;
  
  	jdi = devm_kzalloc(&dsi->dev, sizeof(*jdi), GFP_KERNEL);
  	if (!jdi)
  		return -ENOMEM;
  
  	mipi_dsi_set_drvdata(dsi, jdi);
  
  	jdi->dsi = dsi;
  
  	ret = jdi_panel_add(jdi);
  	if (ret < 0)
  		return ret;
  
  	return mipi_dsi_attach(dsi);
  }
  
  static int jdi_panel_remove(struct mipi_dsi_device *dsi)
  {
  	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
  	int ret;
  
  	ret = jdi_panel_disable(&jdi->base);
  	if (ret < 0)
  		dev_err(&dsi->dev, "failed to disable panel: %d\n", ret);
  
  	ret = mipi_dsi_detach(dsi);
  	if (ret < 0)
  		dev_err(&dsi->dev, "failed to detach from DSI host: %d\n",
  			ret);
  
  	drm_panel_detach(&jdi->base);
  	jdi_panel_del(jdi);
  
  	return 0;
  }
  
  static void jdi_panel_shutdown(struct mipi_dsi_device *dsi)
  {
  	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
  
  	jdi_panel_disable(&jdi->base);
  }
  
  static struct mipi_dsi_driver jdi_panel_driver = {
  	.driver = {
  		.name = "panel-jdi-lt070me05000",
  		.of_match_table = jdi_of_match,
  	},
  	.probe = jdi_panel_probe,
  	.remove = jdi_panel_remove,
  	.shutdown = jdi_panel_shutdown,
  };
  module_mipi_dsi_driver(jdi_panel_driver);
  
  MODULE_AUTHOR("Sumit Semwal <sumit.semwal@linaro.org>");
  MODULE_AUTHOR("Vinay Simha BN <simhavcs@gmail.com>");
  MODULE_DESCRIPTION("JDI LT070ME05000 WUXGA");
  MODULE_LICENSE("GPL v2");
  