drm/panel: Add Ilitek ILI9488 controller driver

Add support for Ilitek ILI9488 DSI controller which is used in
FocusLCDs E35GH-I-MW800-CB 320x480 MIPI DSI panel. The mode timing
was adjusted after STM32MP157 testing. The previous 14.256 MHz mode
worked on AM62P, but was awkward for STM32 DSI/LTDC clock synthesis.

Signed-off-by: Igor Reznichenko <igor@reznichenko.net>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20260617143245.372182-3-igor@reznichenko.net

MAINTAINERS

@@ -8040,6 +8040,12 @@ T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git
 F:	Documentation/devicetree/bindings/display/ilitek,ili9486.yaml
 F:	drivers/gpu/drm/tiny/ili9486.c
 
+DRM DRIVER FOR ILITEK ILI9488 PANELS
+M:	Igor Reznichenko <igor@reznichenko.net>
+S:	Maintained
+F:	Documentation/devicetree/bindings/display/panel/ilitek,ili9488.yaml
+F:	drivers/gpu/drm/panel/panel-ilitek-ili9488.c
+
 DRM DRIVER FOR ILITEK ILI9805 PANELS
 M:	Michael Trimarchi <michael@amarulasolutions.com>
 S:	Maintained

drivers/gpu/drm/panel/Kconfig

@@ -305,6 +305,15 @@ config DRM_PANEL_ILITEK_ILI9341
 	  QVGA (240x320) RGB panels. support serial & parallel rgb
 	  interface.
 
+config DRM_PANEL_ILITEK_ILI9488
+	tristate "Ilitek ILI9488-based panels"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	help
+	  Say Y if you want to enable support for panels based on the
+	  Ilitek ILI9488 controller.
+
 config DRM_PANEL_ILITEK_ILI9805
 	tristate "Ilitek ILI9805-based panels"
 	depends on OF

drivers/gpu/drm/panel/Makefile

@@ -30,6 +30,7 @@ obj-$(CONFIG_DRM_PANEL_HIMAX_HX8394) += panel-himax-hx8394.o
 obj-$(CONFIG_DRM_PANEL_HYDIS_HV101HD1) += panel-hydis-hv101hd1.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_IL9322) += panel-ilitek-ili9322.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9341) += panel-ilitek-ili9341.o
+obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9488) += panel-ilitek-ili9488.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9805) += panel-ilitek-ili9805.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9806E_CORE) += panel-ilitek-ili9806e-core.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9806E_DSI) += panel-ilitek-ili9806e-dsi.o

drivers/gpu/drm/panel/panel-ilitek-ili9488.c

@@ -0,0 +1,289 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_probe_helper.h>
+
+#include <video/mipi_display.h>
+
+struct ili9488_desc {
+	const struct drm_display_mode *display_mode;
+	unsigned long mode_flags;
+	enum mipi_dsi_pixel_format format;
+	unsigned int lanes;
+	unsigned int bpc;
+	void (*init_sequence)(struct mipi_dsi_multi_context *ctx);
+};
+
+struct ili9488 {
+	struct drm_panel panel;
+	struct mipi_dsi_device *dsi;
+	struct gpio_desc *reset;
+	struct regulator_bulk_data supplies[2];
+	const struct ili9488_desc *desc;
+	enum drm_panel_orientation orientation;
+};
+
+static const char * const regulator_names[] = {
+	"vci",
+	"iovcc",
+};
+
+static void e35gh_i_mw800cb_init(struct mipi_dsi_multi_context *ctx)
+{
+	/* Gamma control 1,2 */
+	mipi_dsi_dcs_write_seq_multi(ctx, 0xE0, 0x00, 0x10, 0x14, 0x01, 0x0E, 0x04, 0x33,
+				     0x56, 0x48, 0x03, 0x0C, 0x0B, 0x2B, 0x34, 0x0F);
+	mipi_dsi_dcs_write_seq_multi(ctx, 0xE1, 0x00, 0x12, 0x18, 0x05, 0x12, 0x06, 0x40,
+				     0x34, 0x57, 0x06, 0x10, 0x0C, 0x3B, 0x3F, 0x0F);
+	/* Power control 1,2 */
+	mipi_dsi_dcs_write_seq_multi(ctx, 0xC0, 0x0F, 0x0C);
+	mipi_dsi_dcs_write_seq_multi(ctx, 0xC1, 0x41);
+	/* VCOM Control */
+	mipi_dsi_dcs_write_seq_multi(ctx, 0xC5, 0x00, 0x25, 0x80);
+	mipi_dsi_dcs_write_seq_multi(ctx, 0x36, 0x48);
+	/* Interface pixel format 18bpp */
+	mipi_dsi_dcs_write_seq_multi(ctx, 0x3A, 0x66);
+	mipi_dsi_dcs_write_seq_multi(ctx, 0xB0, 0x00);
+	mipi_dsi_dcs_write_seq_multi(ctx, 0xB1, 0xA0);
+	mipi_dsi_dcs_write_seq_multi(ctx, 0xB4, 0x02);
+	mipi_dsi_dcs_write_seq_multi(ctx, 0xB6, 0x02, 0x02, 0x3B);
+	mipi_dsi_dcs_write_seq_multi(ctx, 0xE9, 0x00);
+	mipi_dsi_dcs_write_seq_multi(ctx, 0xF7, 0xA9, 0x51, 0x2C, 0x82);
+	mipi_dsi_dcs_write_seq_multi(ctx, 0x21);
+}
+
+static const struct drm_display_mode e35gh_i_mw800cb_display_mode = {
+	.clock = 14400,
+
+	.hdisplay = 320,
+	.hsync_start = 320 + 60,
+	.hsync_end = 320 + 60 + 20,
+	.htotal = 320 + 60 + 20 + 42,
+
+	.vdisplay = 480,
+	.vsync_start = 480 + 20,
+	.vsync_end = 480 + 20 + 10,
+	.vtotal = 480 + 20 + 10 + 33,
+
+	.width_mm = 48,
+	.height_mm = 73,
+
+	.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+	.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
+};
+
+static inline struct ili9488 *panel_to_ili9488(struct drm_panel *panel)
+{
+	return container_of(panel, struct ili9488, panel);
+}
+
+static int ili9488_power_on(struct ili9488 *ili)
+{
+	struct mipi_dsi_device *dsi = ili->dsi;
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(ili->supplies), ili->supplies);
+	if (ret < 0) {
+		dev_err(&dsi->dev, "regulator bulk enable failed: %d\n", ret);
+		return ret;
+	}
+
+	gpiod_set_value_cansleep(ili->reset, 0);
+	usleep_range(1000, 5000);
+	gpiod_set_value_cansleep(ili->reset, 1);
+	usleep_range(1000, 5000);
+	gpiod_set_value_cansleep(ili->reset, 0);
+	usleep_range(5000, 10000);
+
+	return 0;
+}
+
+static int ili9488_power_off(struct ili9488 *ili)
+{
+	struct mipi_dsi_device *dsi = ili->dsi;
+	int ret;
+
+	gpiod_set_value_cansleep(ili->reset, 1);
+
+	ret = regulator_bulk_disable(ARRAY_SIZE(ili->supplies), ili->supplies);
+	if (ret)
+		dev_err(&dsi->dev, "regulator bulk disable failed: %d\n", ret);
+
+	return ret;
+}
+
+static int ili9488_activate(struct ili9488 *ili)
+{
+	struct mipi_dsi_multi_context ctx = { .dsi = ili->dsi };
+
+	if (ili->desc->init_sequence)
+		ili->desc->init_sequence(&ctx);
+
+	mipi_dsi_dcs_exit_sleep_mode_multi(&ctx);
+	mipi_dsi_msleep(&ctx, 120);
+	mipi_dsi_dcs_set_display_on_multi(&ctx);
+
+	return ctx.accum_err;
+}
+
+static int ili9488_prepare(struct drm_panel *panel)
+{
+	struct ili9488 *ili = panel_to_ili9488(panel);
+	int ret;
+
+	ret = ili9488_power_on(ili);
+	if (ret)
+		return ret;
+
+	ret = ili9488_activate(ili);
+	if (ret) {
+		ili9488_power_off(ili);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ili9488_deactivate(struct ili9488 *ili)
+{
+	struct mipi_dsi_multi_context ctx = { .dsi = ili->dsi };
+
+	mipi_dsi_dcs_set_display_off_multi(&ctx);
+	mipi_dsi_dcs_enter_sleep_mode_multi(&ctx);
+	mipi_dsi_msleep(&ctx, 120);
+
+	return ctx.accum_err;
+}
+
+static int ili9488_unprepare(struct drm_panel *panel)
+{
+	struct ili9488 *ili = panel_to_ili9488(panel);
+	struct mipi_dsi_device *dsi = ili->dsi;
+	int ret;
+
+	ili9488_deactivate(ili);
+	ret = ili9488_power_off(ili);
+	if (ret < 0)
+		dev_err(&dsi->dev, "power off failed: %d\n", ret);
+
+	return ret;
+}
+
+static int ili9488_get_modes(struct drm_panel *panel, struct drm_connector *connector)
+{
+	struct ili9488 *ili = panel_to_ili9488(panel);
+	const struct drm_display_mode *mode = ili->desc->display_mode;
+
+	connector->display_info.bpc = ili->desc->bpc;
+
+	return drm_connector_helper_get_modes_fixed(connector, mode);
+}
+
+static enum drm_panel_orientation ili9488_get_orientation(struct drm_panel *panel)
+{
+	struct ili9488 *ili = panel_to_ili9488(panel);
+
+	return ili->orientation;
+}
+
+static const struct drm_panel_funcs ili9488_funcs = {
+	.prepare	= ili9488_prepare,
+	.unprepare	= ili9488_unprepare,
+	.get_modes	= ili9488_get_modes,
+	.get_orientation = ili9488_get_orientation,
+};
+
+static int ili9488_dsi_probe(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	struct ili9488 *ili;
+	int i, ret;
+
+	ili = devm_drm_panel_alloc(dev, struct ili9488, panel, &ili9488_funcs,
+				   DRM_MODE_CONNECTOR_DSI);
+	if (IS_ERR(ili))
+		return PTR_ERR(ili);
+
+	ili->desc = device_get_match_data(dev);
+	ili->dsi = dsi;
+
+	dsi->mode_flags = ili->desc->mode_flags;
+	dsi->format = ili->desc->format;
+	dsi->lanes = ili->desc->lanes;
+
+	ili->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(ili->reset))
+		return dev_err_probe(dev, PTR_ERR(ili->reset),
+				     "failed to get reset-gpios\n");
+
+	for (i = 0; i < ARRAY_SIZE(ili->supplies); i++)
+		ili->supplies[i].supply = regulator_names[i];
+
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ili->supplies),
+				      ili->supplies);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to get regulators\n");
+
+	ret = of_drm_get_panel_orientation(dev->of_node, &ili->orientation);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to get orientation\n");
+
+	ret = drm_panel_of_backlight(&ili->panel);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to get backlight\n");
+
+	ili->panel.prepare_prev_first = true;
+
+	ret = devm_drm_panel_add(dev, &ili->panel);
+	if (ret)
+		return ret;
+
+	ret = devm_mipi_dsi_attach(dev, dsi);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to attach to DSI host\n");
+
+	return 0;
+}
+
+static const struct ili9488_desc e35gh_i_mw800cb_desc = {
+	.init_sequence = e35gh_i_mw800cb_init,
+	.display_mode = &e35gh_i_mw800cb_display_mode,
+	.mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
+		      MIPI_DSI_MODE_LPM | MIPI_DSI_CLOCK_NON_CONTINUOUS,
+	.format = MIPI_DSI_FMT_RGB666_PACKED,
+	.lanes = 1,
+	.bpc = 6,
+};
+
+static const struct of_device_id ili9488_of_match[] = {
+	{ .compatible = "focuslcds,e35gh-i-mw800cb", .data = &e35gh_i_mw800cb_desc },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(of, ili9488_of_match);
+
+static struct mipi_dsi_driver ili9488_dsi_driver = {
+	.probe	= ili9488_dsi_probe,
+	.driver = {
+		.name		= "ili9488-dsi",
+		.of_match_table	= ili9488_of_match,
+	},
+};
+module_mipi_dsi_driver(ili9488_dsi_driver);
+
+MODULE_AUTHOR("Igor Reznichenko <igor@reznichenko.net>");
+MODULE_DESCRIPTION("Ilitek ILI9488 Controller Driver");
+MODULE_LICENSE("GPL");