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From: =?utf-8?q?Noralf_Tr=C3=B8nnes?= <noralf@tronnes.org>
To: robh+dt@kernel.org, thierry.reding@gmail.com
Cc: sam@ravnborg.org, maxime@cerno.tech, dave.stevenson@raspberrypi.com,
 david@lechnology.com, devicetree@vger.kernel.org,
 dri-devel@lists.freedesktop.org,
 =?utf-8?q?Noralf_Tr=C3=B8nnes?= <noralf@tronnes.org>
Subject: [PATCH 3/3] drm/panel: Add MIPI DBI compatible SPI driver
Date: Sun, 23 Jan 2022 18:25:20 +0100
Message-Id: <20220123172520.48741-4-noralf@tronnes.org>
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Add a driver that will work with most MIPI DBI compatible SPI panels.
This avoids adding a driver for every new MIPI DBI compatible controller
that is to be used by Linux. The 'model' Device Tree property contains the
name of the display and will be used to load a firmware file that contains
the controller configuration.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
---
 MAINTAINERS                            |   7 +
 drivers/gpu/drm/panel/Kconfig          |  11 +
 drivers/gpu/drm/panel/Makefile         |   1 +
 drivers/gpu/drm/panel/panel-mipi-dbi.c | 385 +++++++++++++++++++++++++
 4 files changed, 404 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-mipi-dbi.c

diff --git a/MAINTAINERS b/MAINTAINERS
index ba6fa65df8bb..8a46c36c50dc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6035,6 +6035,13 @@ T:	git git://anongit.freedesktop.org/drm/drm-misc
 F:	Documentation/devicetree/bindings/display/multi-inno,mi0283qt.txt
 F:	drivers/gpu/drm/tiny/mi0283qt.c
 
+DRM DRIVER FOR MIPI DBI compatible panels
+M:	Noralf Trønnes <noralf@tronnes.org>
+S:	Maintained
+T:	git git://anongit.freedesktop.org/drm/drm-misc
+F:	Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
+F:	drivers/gpu/drm/panel/panel-mipi-dbi.c
+
 DRM DRIVER FOR MSM ADRENO GPU
 M:	Rob Clark <robdclark@gmail.com>
 M:	Sean Paul <sean@poorly.run>
diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 434c2861bb40..1851cda5f877 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -274,6 +274,17 @@ config DRM_PANEL_LG_LG4573
 	  Say Y here if you want to enable support for LG4573 RGB panel.
 	  To compile this driver as a module, choose M here.
 
+config DRM_PANEL_MIPI_DBI
+	tristate "MIPI DBI compatible panel"
+	depends on SPI
+	depends on BACKLIGHT_CLASS_DEVICE
+	depends on DRM_KMS_HELPER
+	select DRM_KMS_CMA_HELPER
+	select DRM_MIPI_DBI
+	help
+	  Say Y here if you want to enable support for MIPI DBI compatible panels.
+	  To compile this driver as a module, choose M here.
+
 config DRM_PANEL_NEC_NL8048HL11
 	tristate "NEC NL8048HL11 RGB panel"
 	depends on GPIOLIB && OF && SPI
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index d99fbbce49d1..a90c30459964 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -25,6 +25,7 @@ obj-$(CONFIG_DRM_PANEL_LEADTEK_LTK050H3146W) += panel-leadtek-ltk050h3146w.o
 obj-$(CONFIG_DRM_PANEL_LEADTEK_LTK500HD1829) += panel-leadtek-ltk500hd1829.o
 obj-$(CONFIG_DRM_PANEL_LG_LB035Q02) += panel-lg-lb035q02.o
 obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
+obj-$(CONFIG_DRM_PANEL_MIPI_DBI) += panel-mipi-dbi.o
 obj-$(CONFIG_DRM_PANEL_NEC_NL8048HL11) += panel-nec-nl8048hl11.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35510) += panel-novatek-nt35510.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35950) += panel-novatek-nt35950.o
diff --git a/drivers/gpu/drm/panel/panel-mipi-dbi.c b/drivers/gpu/drm/panel/panel-mipi-dbi.c
new file mode 100644
index 000000000000..767658426061
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-mipi-dbi.c
@@ -0,0 +1,385 @@
+// 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_fb_helper.h>
+#include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_managed.h>
+#include <drm/drm_mipi_dbi.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 panel configuration is stored in a firmware file. The Device Tree 'model' 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;
+
+	/* Width in pixels */
+	__be16 width;
+	/* Height in pixels */
+	__be16 height;
+
+	/* Width in millimeters (optional) */
+	__be16 width_mm;
+	/* Height in millimeters (optional) */
+	__be16 height_mm;
+
+	/* X-axis panel offset */
+	__be16 x_offset;
+	/* Y-axis panel offset */
+	__be16 y_offset;
+
+	/* 4 pad bytes, must be zero */
+	u8 pad[4];
+
+	/*
+	 * Optional MIPI commands to execute when the display pipeline is enabled.
+	 * This can be 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 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 panel_mipi_dbi_commands *commands = dbidev->driver_private;
+	struct mipi_dbi *dbi = &dbidev->dbi;
+	unsigned int i = 0;
+	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 == 1)
+		goto out_enable;
+
+	if (!commands)
+		goto out_enable;
+
+	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;
+	}
+
+out_enable:
+	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 = {
+	.enable = panel_mipi_dbi_enable,
+	.disable = mipi_dbi_pipe_disable,
+	.update = mipi_dbi_pipe_update,
+};
+
+DEFINE_DRM_GEM_CMA_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_CMA_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_parse_config(struct mipi_dbi_dev *dbidev,
+				       struct drm_display_mode *mode,
+				       const struct firmware *fw)
+{
+	const struct panel_mipi_dbi_config *config = (struct panel_mipi_dbi_config *)fw->data;
+	unsigned int width, height, x_offset, y_offset;
+	struct panel_mipi_dbi_commands *commands;
+	struct drm_device *drm = &dbidev->drm;
+	struct device *dev = dbidev->drm.dev;
+	size_t size = fw->size, commands_len;
+	unsigned int i = 0;
+
+	if (size < sizeof(*config)) {
+		dev_err(dev, "config: file size=%zu is too small\n", size);
+		return -EINVAL;
+	}
+
+	if (memcmp(config->magic, panel_mipi_dbi_magic, sizeof(config->magic))) {
+		dev_err(dev, "config: Bad magic: %15ph\n", config->magic);
+		return -EINVAL;
+	}
+
+	if (config->file_format_version != 1) {
+		dev_err(dev, "config: version=%u is not supported\n", config->file_format_version);
+		return -EINVAL;
+	}
+
+	width = be16_to_cpu(config->width);
+	height = be16_to_cpu(config->height);
+	x_offset = be16_to_cpu(config->x_offset);
+	y_offset = be16_to_cpu(config->y_offset);
+
+	drm_dbg(drm, "size=%zu version=%u\n", size, config->file_format_version);
+	drm_dbg(drm, "width=%u height=%u\n", width, height);
+	drm_dbg(drm, "x_offset=%u y_offset=%u\n", x_offset, y_offset);
+
+	if (width && height) {
+		struct drm_display_mode simple_mode = {
+			DRM_SIMPLE_MODE(width, height, be16_to_cpu(config->width_mm),
+					be16_to_cpu(config->height_mm))
+		};
+
+		*mode = simple_mode;
+	} else {
+		dev_err(dev, "config: width or height can't be zero\n");
+		return -EINVAL;
+	}
+
+	dbidev->left_offset = x_offset;
+	dbidev->top_offset = y_offset;
+
+	commands_len = size - sizeof(*config);
+	if (!commands_len)
+		return 0;
+
+	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 -EINVAL;
+		}
+
+		if (command == 0x00 && num_parameters == 1)
+			drm_dbg(drm, "sleep %ums\n", parameters[0]);
+		else
+			drm_dbg(drm, "command %02x %*ph\n", command, num_parameters, parameters);
+	}
+
+	if (i != commands_len) {
+		dev_err(dev, "config: malformed command array\n");
+		return -EINVAL;
+	}
+
+	commands = devm_kzalloc(dev, sizeof(*commands), GFP_KERNEL);
+	if (!commands)
+		return -ENOMEM;
+
+	commands->len = commands_len;
+	commands->buf = devm_kmemdup(dev, config->commands, commands->len, GFP_KERNEL);
+	if (!commands->buf)
+		return -ENOMEM;
+
+	dbidev->driver_private = commands;
+
+	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;
+	const struct firmware *fw;
+	struct drm_device *drm;
+	struct mipi_dbi *dbi;
+	struct gpio_desc *dc;
+	const char *model;
+	char fw_name[40];
+	int ret;
+
+	ret = device_property_read_string(dev, "model", &model);
+	if (ret) {
+		dev_err(dev, "Failed to get 'model' property\n");
+		return 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;
+
+	snprintf(fw_name, sizeof(fw_name), "%s.bin", model);
+
+	ret = request_firmware(&fw, fw_name, dev);
+	if (ret)
+		return ret;
+
+	ret = panel_mipi_dbi_parse_config(dbidev, &mode, fw);
+	release_firmware(fw);
+	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");
+
+	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");
+
+	dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW);
+	if (IS_ERR(dc))
+		return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\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");
+
+	ret = mipi_dbi_spi_init(spi, dbi, dc);
+	if (ret)
+		return ret;
+
+	if (device_property_present(dev, "write-only"))
+		dbi->read_commands = NULL;
+
+	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 int 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);
+
+	return 0;
+}
+
+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");