drivers/gpu/drm/tiny/panel-mipi-dbi.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * DRM driver for MIPI DBI compatible display panels
  *
  * Copyright 2022 Noralf Trønnes
  */

 #include <linux/backlight.h>
 #include <linux/delay.h>
 #include <linux/firmware.h>
 #include <linux/gpio/consumer.h>
 #include <linux/module.h>
 #include <linux/property.h>
 #include <linux/regulator/consumer.h>
 #include <linux/spi/spi.h>

 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_fbdev_generic.h>
 #include <drm/drm_gem_atomic_helper.h>
 #include <drm/drm_gem_dma_helper.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_mipi_dbi.h>
 #include <drm/drm_modes.h>
 #include <drm/drm_modeset_helper.h>

 #include <video/mipi_display.h>

 static const u8 panel_mipi_dbi_magic[15] = { 'M', 'I', 'P', 'I', ' ', 'D', 'B', 'I',
 					     0, 0, 0, 0, 0, 0, 0 };

 /*
  * The display controller configuration is stored in a firmware file.
  * The Device Tree 'compatible' property value with a '.bin' suffix is passed
  * to request_firmware() to fetch this file.
  */
 struct panel_mipi_dbi_config {
 	/* Magic string: panel_mipi_dbi_magic */
 	u8 magic[15];

 	/* Config file format version */
 	u8 file_format_version;

 	/*
 	 * MIPI commands to execute when the display pipeline is enabled.
 	 * This is used to configure the display controller.
 	 *
 	 * The commands are stored in a byte array with the format:
 	 *     command, num_parameters, [ parameter, ...], command, ...
 	 *
 	 * Some commands require a pause before the next command can be received.
 	 * Inserting a delay in the command sequence is done by using the NOP command with one
 	 * parameter: delay in miliseconds (the No Operation command is part of the MIPI Display
 	 * Command Set where it has no parameters).
 	 *
 	 * Example:
 	 *     command 0x11
 	 *     sleep 120ms
 	 *     command 0xb1 parameters 0x01, 0x2c, 0x2d
 	 *     command 0x29
 	 *
 	 * Byte sequence:
 	 *     0x11 0x00
 	 *     0x00 0x01 0x78
 	 *     0xb1 0x03 0x01 0x2c 0x2d
 	 *     0x29 0x00
 	 */
 	u8 commands[];
 };

 struct panel_mipi_dbi_commands {
 	const u8 *buf;
 	size_t len;
 };

 static struct panel_mipi_dbi_commands *
 panel_mipi_dbi_check_commands(struct device *dev, const struct firmware *fw)
 {
 	const struct panel_mipi_dbi_config *config = (struct panel_mipi_dbi_config *)fw->data;
 	struct panel_mipi_dbi_commands *commands;
 	size_t size = fw->size, commands_len;
 	unsigned int i = 0;

 	if (size < sizeof(*config) + 2) { /* At least 1 command */
 		dev_err(dev, "config: file size=%zu is too small\n", size);
 		return ERR_PTR(-EINVAL);
 	}

 	if (memcmp(config->magic, panel_mipi_dbi_magic, sizeof(config->magic))) {
 		dev_err(dev, "config: Bad magic: %15ph\n", config->magic);
 		return ERR_PTR(-EINVAL);
 	}

 	if (config->file_format_version != 1) {
 		dev_err(dev, "config: version=%u is not supported\n", config->file_format_version);
 		return ERR_PTR(-EINVAL);
 	}

 	drm_dev_dbg(dev, DRM_UT_DRIVER, "size=%zu version=%u\n", size, config->file_format_version);

 	commands_len = size - sizeof(*config);

 	while ((i + 1) < commands_len) {
 		u8 command = config->commands[i++];
 		u8 num_parameters = config->commands[i++];
 		const u8 *parameters = &config->commands[i];

 		i += num_parameters;
 		if (i > commands_len) {
 			dev_err(dev, "config: command=0x%02x num_parameters=%u overflows\n",
 				command, num_parameters);
 			return ERR_PTR(-EINVAL);
 		}

 		if (command == 0x00 && num_parameters == 1)
 			drm_dev_dbg(dev, DRM_UT_DRIVER, "sleep %ums\n", parameters[0]);
 		else
 			drm_dev_dbg(dev, DRM_UT_DRIVER, "command %02x %*ph\n",
 				    command, num_parameters, parameters);
 	}

 	if (i != commands_len) {
 		dev_err(dev, "config: malformed command array\n");
 		return ERR_PTR(-EINVAL);
 	}

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

 	commands->len = commands_len;
 	commands->buf = devm_kmemdup(dev, config->commands, commands->len, GFP_KERNEL);
 	if (!commands->buf)
 		return ERR_PTR(-ENOMEM);

 	return commands;
 }

 static struct panel_mipi_dbi_commands *panel_mipi_dbi_commands_from_fw(struct device *dev)
 {
 	struct panel_mipi_dbi_commands *commands;
 	const struct firmware *fw;
 	const char *compatible;
 	char fw_name[40];
 	int ret;

 	ret = of_property_read_string_index(dev->of_node, "compatible", 0, &compatible);
 	if (ret)
 		return ERR_PTR(ret);

 	snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible);
 	ret = request_firmware(&fw, fw_name, dev);
 	if (ret) {
 		dev_err(dev, "No config file found for compatible '%s' (error=%d)\n",
 			compatible, ret);

 		return ERR_PTR(ret);
 	}

 	commands = panel_mipi_dbi_check_commands(dev, fw);
 	release_firmware(fw);

 	return commands;
 }

 static void panel_mipi_dbi_commands_execute(struct mipi_dbi *dbi,
 					    struct panel_mipi_dbi_commands *commands)
 {
 	unsigned int i = 0;

 	if (!commands)
 		return;

 	while (i < commands->len) {
 		u8 command = commands->buf[i++];
 		u8 num_parameters = commands->buf[i++];
 		const u8 *parameters = &commands->buf[i];

 		if (command == 0x00 && num_parameters == 1)
 			msleep(parameters[0]);
 		else if (num_parameters)
 			mipi_dbi_command_stackbuf(dbi, command, parameters, num_parameters);
 		else
 			mipi_dbi_command(dbi, command);

 		i += num_parameters;
 	}
 }

 static void panel_mipi_dbi_enable(struct drm_simple_display_pipe *pipe,
 				  struct drm_crtc_state *crtc_state,
 				  struct drm_plane_state *plane_state)
 {
 	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
 	struct mipi_dbi *dbi = &dbidev->dbi;
 	int ret, idx;

 	if (!drm_dev_enter(pipe->crtc.dev, &idx))
 		return;

 	drm_dbg(pipe->crtc.dev, "\n");

 	ret = mipi_dbi_poweron_conditional_reset(dbidev);
 	if (ret < 0)
 		goto out_exit;
 	if (!ret)
 		panel_mipi_dbi_commands_execute(dbi, dbidev->driver_private);

 	mipi_dbi_enable_flush(dbidev, crtc_state, plane_state);
 out_exit:
 	drm_dev_exit(idx);
 }

 static const struct drm_simple_display_pipe_funcs panel_mipi_dbi_pipe_funcs = {
 	DRM_MIPI_DBI_SIMPLE_DISPLAY_PIPE_FUNCS(panel_mipi_dbi_enable),
 };

 DEFINE_DRM_GEM_DMA_FOPS(panel_mipi_dbi_fops);

 static const struct drm_driver panel_mipi_dbi_driver = {
 	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 	.fops			= &panel_mipi_dbi_fops,
 	DRM_GEM_DMA_DRIVER_OPS_VMAP,
 	.debugfs_init		= mipi_dbi_debugfs_init,
 	.name			= "panel-mipi-dbi",
 	.desc			= "MIPI DBI compatible display panel",
 	.date			= "20220103",
 	.major			= 1,
 	.minor			= 0,
 };

 static int panel_mipi_dbi_get_mode(struct mipi_dbi_dev *dbidev, struct drm_display_mode *mode)
 {
 	struct device *dev = dbidev->drm.dev;
 	u16 hback_porch, vback_porch;
 	int ret;

 	ret = of_get_drm_panel_display_mode(dev->of_node, mode, NULL);
 	if (ret) {
 		dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n", dev->of_node, ret);
 		return ret;
 	}

 	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;

 	hback_porch = mode->htotal - mode->hsync_end;
 	vback_porch = mode->vtotal - mode->vsync_end;

 	/*
 	 * Make sure width and height are set and that only back porch and
 	 * pixelclock are set in the other timing values. Also check that
 	 * width and height don't exceed the 16-bit value specified by MIPI DCS.
 	 */
 	if (!mode->hdisplay || !mode->vdisplay || mode->flags ||
 	    mode->hsync_end > mode->hdisplay || (hback_porch + mode->hdisplay) > 0xffff ||
 	    mode->vsync_end > mode->vdisplay || (vback_porch + mode->vdisplay) > 0xffff) {
 		dev_err(dev, "%pOF: panel-timing out of bounds\n", dev->of_node);
 		return -EINVAL;
 	}

 	/* The driver doesn't use the pixel clock but it is mandatory so fake one if not set */
 	if (!mode->clock)
 		mode->clock = mode->htotal * mode->vtotal * 60 / 1000;

 	dbidev->top_offset = vback_porch;
 	dbidev->left_offset = hback_porch;

 	return 0;
 }

 static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
 {
 	struct device *dev = &spi->dev;
 	struct drm_display_mode mode;
 	struct mipi_dbi_dev *dbidev;
 	struct drm_device *drm;
 	struct mipi_dbi *dbi;
 	struct gpio_desc *dc;
 	int ret;

 	dbidev = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver, struct mipi_dbi_dev, drm);
 	if (IS_ERR(dbidev))
 		return PTR_ERR(dbidev);

 	dbi = &dbidev->dbi;
 	drm = &dbidev->drm;

 	ret = panel_mipi_dbi_get_mode(dbidev, &mode);
 	if (ret)
 		return ret;

 	dbidev->regulator = devm_regulator_get(dev, "power");
 	if (IS_ERR(dbidev->regulator))
 		return dev_err_probe(dev, PTR_ERR(dbidev->regulator),
 				     "Failed to get regulator 'power'\n");

 	dbidev->io_regulator = devm_regulator_get(dev, "io");
 	if (IS_ERR(dbidev->io_regulator))
 		return dev_err_probe(dev, PTR_ERR(dbidev->io_regulator),
 				     "Failed to get regulator 'io'\n");

 	dbidev->backlight = devm_of_find_backlight(dev);
 	if (IS_ERR(dbidev->backlight))
 		return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed to get backlight\n");

 	dbi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(dbi->reset))
 		return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");

 	/* Multiple panels can share the "dc" GPIO, but only if they are on the same SPI bus! */
 	dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE);
 	if (IS_ERR(dc))
 		return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\n");

 	ret = mipi_dbi_spi_init(spi, dbi, dc);
 	if (ret)
 		return ret;

 	if (device_property_present(dev, "write-only"))
 		dbi->read_commands = NULL;

 	dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev);
 	if (IS_ERR(dbidev->driver_private))
 		return PTR_ERR(dbidev->driver_private);

 	ret = mipi_dbi_dev_init(dbidev, &panel_mipi_dbi_pipe_funcs, &mode, 0);
 	if (ret)
 		return ret;

 	drm_mode_config_reset(drm);

 	ret = drm_dev_register(drm, 0);
 	if (ret)
 		return ret;

 	spi_set_drvdata(spi, drm);

 	drm_fbdev_generic_setup(drm, 0);

 	return 0;
 }

 static void panel_mipi_dbi_spi_remove(struct spi_device *spi)
 {
 	struct drm_device *drm = spi_get_drvdata(spi);

 	drm_dev_unplug(drm);
 	drm_atomic_helper_shutdown(drm);
 }

 static void panel_mipi_dbi_spi_shutdown(struct spi_device *spi)
 {
 	drm_atomic_helper_shutdown(spi_get_drvdata(spi));
 }

 static int __maybe_unused panel_mipi_dbi_pm_suspend(struct device *dev)
 {
 	return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
 }

 static int __maybe_unused panel_mipi_dbi_pm_resume(struct device *dev)
 {
 	drm_mode_config_helper_resume(dev_get_drvdata(dev));

 	return 0;
 }

 static const struct dev_pm_ops panel_mipi_dbi_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(panel_mipi_dbi_pm_suspend, panel_mipi_dbi_pm_resume)
 };

 static const struct of_device_id panel_mipi_dbi_spi_of_match[] = {
 	{ .compatible = "panel-mipi-dbi-spi" },
 	{},
 };
 MODULE_DEVICE_TABLE(of, panel_mipi_dbi_spi_of_match);

 static const struct spi_device_id panel_mipi_dbi_spi_id[] = {
 	{ "panel-mipi-dbi-spi", 0 },
 	{ },
 };
 MODULE_DEVICE_TABLE(spi, panel_mipi_dbi_spi_id);

 static struct spi_driver panel_mipi_dbi_spi_driver = {
 	.driver = {
 		.name = "panel-mipi-dbi-spi",
 		.owner = THIS_MODULE,
 		.of_match_table = panel_mipi_dbi_spi_of_match,
 		.pm = &panel_mipi_dbi_pm_ops,
 	},
 	.id_table = panel_mipi_dbi_spi_id,
 	.probe = panel_mipi_dbi_spi_probe,
 	.remove = panel_mipi_dbi_spi_remove,
 	.shutdown = panel_mipi_dbi_spi_shutdown,
 };
 module_spi_driver(panel_mipi_dbi_spi_driver);

 MODULE_DESCRIPTION("MIPI DBI compatible display panel driver");
 MODULE_AUTHOR("Noralf Trønnes");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* DRM driver for MIPI DBI compatible display panels
	*
	* Copyright 2022 Noralf Trønnes
	*/

	#include <linux/backlight.h>
	#include <linux/delay.h>
	#include <linux/firmware.h>
	#include <linux/gpio/consumer.h>
	#include <linux/module.h>
	#include <linux/property.h>
	#include <linux/regulator/consumer.h>
	#include <linux/spi/spi.h>

	#include <drm/drm_atomic_helper.h>
	#include <drm/drm_drv.h>
	#include <drm/drm_fbdev_generic.h>
	#include <drm/drm_gem_atomic_helper.h>
	#include <drm/drm_gem_dma_helper.h>
	#include <drm/drm_managed.h>
	#include <drm/drm_mipi_dbi.h>
	#include <drm/drm_modes.h>
	#include <drm/drm_modeset_helper.h>

	#include <video/mipi_display.h>

	static const u8 panel_mipi_dbi_magic[15] = { 'M', 'I', 'P', 'I', ' ', 'D', 'B', 'I',
	0, 0, 0, 0, 0, 0, 0 };

	/*
	* The display controller configuration is stored in a firmware file.
	* The Device Tree 'compatible' property value with a '.bin' suffix is passed
	* to request_firmware() to fetch this file.
	*/
	struct panel_mipi_dbi_config {
	/* Magic string: panel_mipi_dbi_magic */
	u8 magic[15];

	/* Config file format version */
	u8 file_format_version;

	/*
	* MIPI commands to execute when the display pipeline is enabled.
	* This is used to configure the display controller.
	*
	* The commands are stored in a byte array with the format:
	* command, num_parameters, [ parameter, ...], command, ...
	*
	* Some commands require a pause before the next command can be received.
	* Inserting a delay in the command sequence is done by using the NOP command with one
	* parameter: delay in miliseconds (the No Operation command is part of the MIPI Display
	* Command Set where it has no parameters).
	*
	* Example:
	* command 0x11
	* sleep 120ms
	* command 0xb1 parameters 0x01, 0x2c, 0x2d
	* command 0x29
	*
	* Byte sequence:
	* 0x11 0x00
	* 0x00 0x01 0x78
	* 0xb1 0x03 0x01 0x2c 0x2d
	* 0x29 0x00
	*/
	u8 commands[];
	};

	struct panel_mipi_dbi_commands {
	const u8 *buf;
	size_t len;
	};

	static struct panel_mipi_dbi_commands *
	panel_mipi_dbi_check_commands(struct device dev, const struct firmware fw)
	{
	const struct panel_mipi_dbi_config config = (struct panel_mipi_dbi_config )fw->data;
	struct panel_mipi_dbi_commands *commands;
	size_t size = fw->size, commands_len;
	unsigned int i = 0;

	if (size < sizeof(config) + 2) { / At least 1 command */
	dev_err(dev, "config: file size=%zu is too small\n", size);
	return ERR_PTR(-EINVAL);
	}

	if (memcmp(config->magic, panel_mipi_dbi_magic, sizeof(config->magic))) {
	dev_err(dev, "config: Bad magic: %15ph\n", config->magic);
	return ERR_PTR(-EINVAL);
	}

	if (config->file_format_version != 1) {
	dev_err(dev, "config: version=%u is not supported\n", config->file_format_version);
	return ERR_PTR(-EINVAL);
	}

	drm_dev_dbg(dev, DRM_UT_DRIVER, "size=%zu version=%u\n", size, config->file_format_version);

	commands_len = size - sizeof(*config);

	while ((i + 1) < commands_len) {
	u8 command = config->commands[i++];
	u8 num_parameters = config->commands[i++];
	const u8 *parameters = &config->commands[i];

	i += num_parameters;
	if (i > commands_len) {
	dev_err(dev, "config: command=0x%02x num_parameters=%u overflows\n",
	command, num_parameters);
	return ERR_PTR(-EINVAL);
	}

	if (command == 0x00 && num_parameters == 1)
	drm_dev_dbg(dev, DRM_UT_DRIVER, "sleep %ums\n", parameters[0]);
	else
	drm_dev_dbg(dev, DRM_UT_DRIVER, "command %02x %*ph\n",
	command, num_parameters, parameters);
	}

	if (i != commands_len) {
	dev_err(dev, "config: malformed command array\n");
	return ERR_PTR(-EINVAL);
	}

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

	commands->len = commands_len;
	commands->buf = devm_kmemdup(dev, config->commands, commands->len, GFP_KERNEL);
	if (!commands->buf)
	return ERR_PTR(-ENOMEM);

	return commands;
	}

	static struct panel_mipi_dbi_commands panel_mipi_dbi_commands_from_fw(struct device dev)
	{
	struct panel_mipi_dbi_commands *commands;
	const struct firmware *fw;
	const char *compatible;
	char fw_name[40];
	int ret;

	ret = of_property_read_string_index(dev->of_node, "compatible", 0, &compatible);
	if (ret)
	return ERR_PTR(ret);

	snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible);
	ret = request_firmware(&fw, fw_name, dev);
	if (ret) {
	dev_err(dev, "No config file found for compatible '%s' (error=%d)\n",
	compatible, ret);

	return ERR_PTR(ret);
	}

	commands = panel_mipi_dbi_check_commands(dev, fw);
	release_firmware(fw);

	return commands;
	}

	static void panel_mipi_dbi_commands_execute(struct mipi_dbi *dbi,
	struct panel_mipi_dbi_commands *commands)
	{
	unsigned int i = 0;

	if (!commands)
	return;

	while (i < commands->len) {
	u8 command = commands->buf[i++];
	u8 num_parameters = commands->buf[i++];
	const u8 *parameters = &commands->buf[i];

	if (command == 0x00 && num_parameters == 1)
	msleep(parameters[0]);
	else if (num_parameters)
	mipi_dbi_command_stackbuf(dbi, command, parameters, num_parameters);
	else
	mipi_dbi_command(dbi, command);

	i += num_parameters;
	}
	}

	static void panel_mipi_dbi_enable(struct drm_simple_display_pipe *pipe,
	struct drm_crtc_state *crtc_state,
	struct drm_plane_state *plane_state)
	{
	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
	struct mipi_dbi *dbi = &dbidev->dbi;
	int ret, idx;

	if (!drm_dev_enter(pipe->crtc.dev, &idx))
	return;

	drm_dbg(pipe->crtc.dev, "\n");

	ret = mipi_dbi_poweron_conditional_reset(dbidev);
	if (ret < 0)
	goto out_exit;
	if (!ret)
	panel_mipi_dbi_commands_execute(dbi, dbidev->driver_private);

	mipi_dbi_enable_flush(dbidev, crtc_state, plane_state);
	out_exit:
	drm_dev_exit(idx);
	}

	static const struct drm_simple_display_pipe_funcs panel_mipi_dbi_pipe_funcs = {
	DRM_MIPI_DBI_SIMPLE_DISPLAY_PIPE_FUNCS(panel_mipi_dbi_enable),
	};

	DEFINE_DRM_GEM_DMA_FOPS(panel_mipi_dbi_fops);

	static const struct drm_driver panel_mipi_dbi_driver = {
	.driver_features = DRIVER_GEM \| DRIVER_MODESET \| DRIVER_ATOMIC,
	.fops = &panel_mipi_dbi_fops,
	DRM_GEM_DMA_DRIVER_OPS_VMAP,
	.debugfs_init = mipi_dbi_debugfs_init,
	.name = "panel-mipi-dbi",
	.desc = "MIPI DBI compatible display panel",
	.date = "20220103",
	.major = 1,
	.minor = 0,
	};

	static int panel_mipi_dbi_get_mode(struct mipi_dbi_dev dbidev, struct drm_display_mode mode)
	{
	struct device *dev = dbidev->drm.dev;
	u16 hback_porch, vback_porch;
	int ret;

	ret = of_get_drm_panel_display_mode(dev->of_node, mode, NULL);
	if (ret) {
	dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n", dev->of_node, ret);
	return ret;
	}

	mode->type = DRM_MODE_TYPE_DRIVER \| DRM_MODE_TYPE_PREFERRED;

	hback_porch = mode->htotal - mode->hsync_end;
	vback_porch = mode->vtotal - mode->vsync_end;

	/*
	* Make sure width and height are set and that only back porch and
	* pixelclock are set in the other timing values. Also check that
	* width and height don't exceed the 16-bit value specified by MIPI DCS.
	*/
	if (!mode->hdisplay \|\| !mode->vdisplay \|\| mode->flags \|\|
	mode->hsync_end > mode->hdisplay \|\| (hback_porch + mode->hdisplay) > 0xffff \|\|
	mode->vsync_end > mode->vdisplay \|\| (vback_porch + mode->vdisplay) > 0xffff) {
	dev_err(dev, "%pOF: panel-timing out of bounds\n", dev->of_node);
	return -EINVAL;
	}

	/* The driver doesn't use the pixel clock but it is mandatory so fake one if not set */
	if (!mode->clock)
	mode->clock = mode->htotal * mode->vtotal * 60 / 1000;

	dbidev->top_offset = vback_porch;
	dbidev->left_offset = hback_porch;

	return 0;
	}

	static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
	{
	struct device *dev = &spi->dev;
	struct drm_display_mode mode;
	struct mipi_dbi_dev *dbidev;
	struct drm_device *drm;
	struct mipi_dbi *dbi;
	struct gpio_desc *dc;
	int ret;

	dbidev = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver, struct mipi_dbi_dev, drm);
	if (IS_ERR(dbidev))
	return PTR_ERR(dbidev);

	dbi = &dbidev->dbi;
	drm = &dbidev->drm;

	ret = panel_mipi_dbi_get_mode(dbidev, &mode);
	if (ret)
	return ret;

	dbidev->regulator = devm_regulator_get(dev, "power");
	if (IS_ERR(dbidev->regulator))
	return dev_err_probe(dev, PTR_ERR(dbidev->regulator),
	"Failed to get regulator 'power'\n");

	dbidev->io_regulator = devm_regulator_get(dev, "io");
	if (IS_ERR(dbidev->io_regulator))
	return dev_err_probe(dev, PTR_ERR(dbidev->io_regulator),
	"Failed to get regulator 'io'\n");

	dbidev->backlight = devm_of_find_backlight(dev);
	if (IS_ERR(dbidev->backlight))
	return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed to get backlight\n");

	dbi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(dbi->reset))
	return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");

	/* Multiple panels can share the "dc" GPIO, but only if they are on the same SPI bus! */
	dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW \| GPIOD_FLAGS_BIT_NONEXCLUSIVE);
	if (IS_ERR(dc))
	return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\n");

	ret = mipi_dbi_spi_init(spi, dbi, dc);
	if (ret)
	return ret;

	if (device_property_present(dev, "write-only"))
	dbi->read_commands = NULL;

	dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev);
	if (IS_ERR(dbidev->driver_private))
	return PTR_ERR(dbidev->driver_private);

	ret = mipi_dbi_dev_init(dbidev, &panel_mipi_dbi_pipe_funcs, &mode, 0);
	if (ret)
	return ret;

	drm_mode_config_reset(drm);

	ret = drm_dev_register(drm, 0);
	if (ret)
	return ret;

	spi_set_drvdata(spi, drm);

	drm_fbdev_generic_setup(drm, 0);

	return 0;
	}

	static void panel_mipi_dbi_spi_remove(struct spi_device *spi)
	{
	struct drm_device *drm = spi_get_drvdata(spi);

	drm_dev_unplug(drm);
	drm_atomic_helper_shutdown(drm);
	}

	static void panel_mipi_dbi_spi_shutdown(struct spi_device *spi)
	{
	drm_atomic_helper_shutdown(spi_get_drvdata(spi));
	}

	static int __maybe_unused panel_mipi_dbi_pm_suspend(struct device *dev)
	{
	return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
	}

	static int __maybe_unused panel_mipi_dbi_pm_resume(struct device *dev)
	{
	drm_mode_config_helper_resume(dev_get_drvdata(dev));

	return 0;
	}

	static const struct dev_pm_ops panel_mipi_dbi_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(panel_mipi_dbi_pm_suspend, panel_mipi_dbi_pm_resume)
	};

	static const struct of_device_id panel_mipi_dbi_spi_of_match[] = {
	{ .compatible = "panel-mipi-dbi-spi" },
	{},
	};
	MODULE_DEVICE_TABLE(of, panel_mipi_dbi_spi_of_match);

	static const struct spi_device_id panel_mipi_dbi_spi_id[] = {
	{ "panel-mipi-dbi-spi", 0 },
	{ },
	};
	MODULE_DEVICE_TABLE(spi, panel_mipi_dbi_spi_id);

	static struct spi_driver panel_mipi_dbi_spi_driver = {
	.driver = {
	.name = "panel-mipi-dbi-spi",
	.owner = THIS_MODULE,
	.of_match_table = panel_mipi_dbi_spi_of_match,
	.pm = &panel_mipi_dbi_pm_ops,
	},
	.id_table = panel_mipi_dbi_spi_id,
	.probe = panel_mipi_dbi_spi_probe,
	.remove = panel_mipi_dbi_spi_remove,
	.shutdown = panel_mipi_dbi_spi_shutdown,
	};
	module_spi_driver(panel_mipi_dbi_spi_driver);

	MODULE_DESCRIPTION("MIPI DBI compatible display panel driver");
	MODULE_AUTHOR("Noralf Trønnes");
	MODULE_LICENSE("GPL");