drivers/gpu/drm/panel/panel-arm-versatile.c - linux-mtk - Git at Google

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

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

 #include <video/of_videomode.h>
 #include <video/videomode.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,
 			.vrefresh = 116,
 			.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,
 			.vrefresh = 60,
 			.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,
 			.vrefresh = 390,
 			.flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC,
 		},
 		.bus_flags = DRM_BUS_FLAG_PIXDATA_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,
 			.vrefresh = 116,
 			.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
 		},
 		.bus_flags = DRM_BUS_FLAG_PIXDATA_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 = panel->connector;
 	struct versatile_panel *vpanel = to_versatile_panel(panel);
 	struct drm_display_mode *mode;

 	strncpy(connector->display_info.name, vpanel->panel_type->name,
 		DRM_DISPLAY_INFO_LEN);
 	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(panel->drm, &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);
 	vpanel->panel.dev = dev;
 	vpanel->panel.funcs = &versatile_panel_drm_funcs;

 	return drm_panel_add(&vpanel->panel);
 }

 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");
	// 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 <drm/drmP.h>
	#include <drm/drm_panel.h>

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

	#include <video/of_videomode.h>
	#include <video/videomode.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,
	.vrefresh = 116,
	.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,
	.vrefresh = 60,
	.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,
	.vrefresh = 390,
	.flags = DRM_MODE_FLAG_PHSYNC \| DRM_MODE_FLAG_PVSYNC,
	},
	.bus_flags = DRM_BUS_FLAG_PIXDATA_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,
	.vrefresh = 116,
	.flags = DRM_MODE_FLAG_NHSYNC \| DRM_MODE_FLAG_NVSYNC,
	},
	.bus_flags = DRM_BUS_FLAG_PIXDATA_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 = panel->connector;
	struct versatile_panel *vpanel = to_versatile_panel(panel);
	struct drm_display_mode *mode;

	strncpy(connector->display_info.name, vpanel->panel_type->name,
	DRM_DISPLAY_INFO_LEN);
	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(panel->drm, &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);
	vpanel->panel.dev = dev;
	vpanel->panel.funcs = &versatile_panel_drm_funcs;

	return drm_panel_add(&vpanel->panel);
	}

	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");