Re: [PATCH v6 2/2] drm/panel: Add Ilitek ILI9488 controller driver

[Neil Armstrong <neil.armstrong@linaro.org>]

On 6/17/26 16:32, Igor Reznichenko wrote:
> 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>
> ---
>   MAINTAINERS                                  |   6 +
>   drivers/gpu/drm/panel/Kconfig                |   9 +
>   drivers/gpu/drm/panel/Makefile               |   1 +
>   drivers/gpu/drm/panel/panel-ilitek-ili9488.c | 289 +++++++++++++++++++
>   4 files changed, 305 insertions(+)
>   create mode 100644 drivers/gpu/drm/panel/panel-ilitek-ili9488.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index ac87c217ab1f..987635948cde 100644
> --- a/MAINTAINERS
> +++ b/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
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 7450b27622a2..37987e47f3f7 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -284,6 +284,15 @@ 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
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index c2c5cf817116..a1344a0a3fd0 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -28,6 +28,7 @@ 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
> diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili9488.c b/drivers/gpu/drm/panel/panel-ilitek-ili9488.c
> new file mode 100644
> index 000000000000..7302766034fc
> --- /dev/null
> +++ b/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");

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Thanks,
Neil