Re: [PATCH 2/2] drm/panel: add Ilitek ILI7836A panel driver

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

On 8/8/26 21:01, Aaron Kling via B4 Relay wrote:
> From: Aaron Kling <webgeek1234@gmail.com>
> 
> This is a DDIC which can be used in various panels. The first
> supported panel is the one used in the Retroid Pocket Nova.
> 
> Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
> ---
>   drivers/gpu/drm/panel/Kconfig                 |  11 +
>   drivers/gpu/drm/panel/Makefile                |   1 +
>   drivers/gpu/drm/panel/panel-ilitek-ili7836a.c | 297 ++++++++++++++++++++++++++
>   3 files changed, 309 insertions(+)
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index cbdf7b8f7f7af..792d6b92798d9 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -298,6 +298,17 @@ config DRM_PANEL_ILITEK_ILI7807S
>   
>   	  If M is selected the module will be called panel-ilitek-ili7807s.
>   
> +config DRM_PANEL_ILITEK_ILI7836A
> +	tristate "Ilitek ILI7836A-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 ILI7836A DDIC.
> +
> +	  If M is selected the module will be called panel-ilitek-ili7836a.
> +
>   config DRM_PANEL_ILITEK_IL9322
>   	tristate "Ilitek ILI9322 320x240 QVGA panels"
>   	depends on OF && SPI
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 3b523cf378330..be96f4e8112da 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -29,6 +29,7 @@ obj-$(CONFIG_DRM_PANEL_HIMAX_HX83121A) += panel-himax-hx83121a.o
>   obj-$(CONFIG_DRM_PANEL_HIMAX_HX8394) += panel-himax-hx8394.o
>   obj-$(CONFIG_DRM_PANEL_HYDIS_HV101HD1) += panel-hydis-hv101hd1.o
>   obj-$(CONFIG_DRM_PANEL_ILITEK_ILI7807S) += panel-ilitek-ili7807s.o
> +obj-$(CONFIG_DRM_PANEL_ILITEK_ILI7836A) += panel-ilitek-ili7836a.o
>   obj-$(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
> diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili7836a.c b/drivers/gpu/drm/panel/panel-ilitek-ili7836a.c
> new file mode 100644
> index 0000000000000..f6331129dadf2
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-ilitek-ili7836a.c
> @@ -0,0 +1,297 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include <linux/backlight.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <drm/drm_connector.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_modes.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_probe_helper.h>
> +
> +#include <video/mipi_display.h>
> +
> +static const struct regulator_bulk_data ili7836a_supplies[] = {
> +	{ .supply = "vddio", },
> +	{ .supply = "avdd", },
> +};
> +
> +struct ili7836a_panel {
> +	struct drm_panel panel;
> +	struct drm_connector *connector;
> +	struct mipi_dsi_device *dsi;
> +	struct regulator_bulk_data *supplies;
> +	struct gpio_desc *reset_gpio;
> +	struct ili7836a_desc *desc;
> +	enum drm_panel_orientation orientation;
> +};
> +
> +struct ili7836a_desc {
> +	unsigned int width_mm;
> +	unsigned int height_mm;
> +	unsigned int bpc;
> +
> +	const struct drm_display_mode *modes;
> +	unsigned int num_modes;
> +};
> +
> +static inline struct ili7836a_panel *to_ili7836a_panel(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct ili7836a_panel, panel);
> +}
> +
> +static void ili7836a_reset(struct ili7836a_panel *ctx)
> +{
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
> +	msleep(20);
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +	msleep(20);
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
> +	msleep(20);
> +}
> +
> +static int ili7836a_on(struct ili7836a_panel *ctx)
> +{
> +	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
> +
> +	ctx->dsi->mode_flags |= MIPI_DSI_MODE_LPM;
> +
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0x5a, 0xa5, 0x08);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xc8, 0x62);
> +
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0x5a, 0xa5, 0x21);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xa4, 0x38);
> +
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0x5a, 0xa5, 0x23);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x85, 0x15);
> +
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0x5a, 0xa5, 0x00);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x60, 0x00);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6d, 0x00);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x35);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x53, 0x20);
> +
> +	mipi_dsi_dcs_exit_sleep_mode_multi(&dsi_ctx);
> +	mipi_dsi_msleep(&dsi_ctx, 120);
> +
> +	mipi_dsi_dcs_set_display_on_multi(&dsi_ctx);
> +	mipi_dsi_msleep(&dsi_ctx, 20);
> +
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0x5a, 0xa5, 0x22);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xe1, 0x01);
> +
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0x5a, 0xa5, 0x00);
> +
> +	return dsi_ctx.accum_err;
> +}
> +
> +static int ili7836a_disable(struct drm_panel *panel)
> +{
> +	struct ili7836a_panel *ctx = to_ili7836a_panel(panel);
> +	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
> +
> +	ctx->dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
> +	mipi_dsi_msleep(&dsi_ctx, 20);
> +	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx);
> +	mipi_dsi_msleep(&dsi_ctx, 120);
> +
> +	return dsi_ctx.accum_err;
> +}
> +
> +static int ili7836a_prepare(struct drm_panel *panel)
> +{
> +	struct ili7836a_panel *ctx = to_ili7836a_panel(panel);
> +	struct device *dev = &ctx->dsi->dev;
> +	int ret;
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(ili7836a_supplies), ctx->supplies);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to enable regulators: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ili7836a_reset(ctx);
> +
> +	ret = ili7836a_on(ctx);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to initialize panel: %d\n", ret);
> +		gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +		regulator_bulk_disable(ARRAY_SIZE(ili7836a_supplies), ctx->supplies);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ili7836a_unprepare(struct drm_panel *panel)
> +{
> +	struct ili7836a_panel *ctx = to_ili7836a_panel(panel);
> +
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +	regulator_bulk_disable(ARRAY_SIZE(ili7836a_supplies), ctx->supplies);
> +
> +	return 0;
> +}
> +
> +static const struct drm_display_mode nova_modes[] = {
> +	{
> +		/* 120Hz */
> +		.clock = (1280 + 12 + 2 + 8) * (960 + 12 + 2 + 24) * 120 / 1000,
> +		.hdisplay = 1280,
> +		.hsync_start = 1280 + 12,
> +		.hsync_end = 1280 + 12 + 2,
> +		.htotal = 1280 + 12 + 2 + 8,
> +		.vdisplay = 960,
> +		.vsync_start = 960 + 12,
> +		.vsync_end = 960 + 12 + 2,
> +		.vtotal = 960 + 12 + 2 + 24,
> +	}
> +};
> +
> +static struct ili7836a_desc nova_desc = {
> +	.modes = nova_modes,
> +	.num_modes = ARRAY_SIZE(nova_modes),
> +	.width_mm = 91,
> +	.height_mm = 68,
> +	.bpc = 8,
> +};
> +
> +static int ili7836a_get_modes(struct drm_panel *panel,
> +					struct drm_connector *connector)
> +{
> +	struct ili7836a_panel *ctx = to_ili7836a_panel(panel);
> +
> +	return drm_connector_helper_get_modes_fixed(connector, ctx->desc->modes);
> +}
> +
> +static enum drm_panel_orientation ili7836a_get_orientation(struct drm_panel *panel)
> +{
> +	struct ili7836a_panel *ctx = to_ili7836a_panel(panel);
> +
> +	return ctx->orientation;
> +}
> +
> +static const struct drm_panel_funcs ili7836a_panel_funcs = {
> +	.prepare = ili7836a_prepare,
> +	.unprepare = ili7836a_unprepare,
> +	.disable = ili7836a_disable,
> +	.get_modes = ili7836a_get_modes,
> +	.get_orientation = ili7836a_get_orientation,
> +};
> +
> +static int ili7836a_bl_update_status(struct backlight_device *bl)
> +{
> +	struct mipi_dsi_device *dsi = bl_get_data(bl);
> +	u16 brightness = backlight_get_brightness(bl);
> +	int ret;
> +
> +	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	ret = mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
> +	if (ret < 0)
> +		return ret;
> +
> +	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
> +
> +	return 0;
> +}
> +
> +static const struct backlight_ops ili7836a_bl_ops = {
> +	.update_status = ili7836a_bl_update_status,
> +};
> +
> +static struct backlight_device *
> +ili7836a_create_backlight(struct mipi_dsi_device *dsi)
> +{
> +	struct device *dev = &dsi->dev;
> +	const struct backlight_properties props = {
> +		.type = BACKLIGHT_RAW,
> +		.brightness = 3445,
> +		.max_brightness = 3445,
> +	};
> +
> +	return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
> +					      &ili7836a_bl_ops, &props);
> +}
> +
> +static int ili7836a_probe(struct mipi_dsi_device *dsi)
> +{
> +	struct device *dev = &dsi->dev;
> +	struct ili7836a_panel *ctx;
> +	int ret;
> +
> +	ctx = devm_drm_panel_alloc(dev, __typeof(*ctx), panel,
> +				   &ili7836a_panel_funcs,
> +				   DRM_MODE_CONNECTOR_DSI);
> +	if (IS_ERR(ctx))
> +		return PTR_ERR(ctx);
> +
> +	ctx->desc = (struct ili7836a_desc *)of_device_get_match_data(dev);
> +	if (!ctx->desc)
> +		return -ENODEV;
> +
> +	ret = devm_regulator_bulk_get_const(dev,
> +					    ARRAY_SIZE(ili7836a_supplies),
> +					    ili7836a_supplies,
> +					    &ctx->supplies);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Failed to get regulators\n");
> +
> +	ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(ctx->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
> +				     "Failed to get reset-gpios\n");
> +
> +	ret = drm_of_get_panel_orientation(dev->of_node, &ctx->orientation);
> +	if (ret < 0) {
> +		dev_err(dev, "%pOF: failed to get orientation %d\n", dev->of_node, ret);
> +		return ret;
> +	}
> +
> +	ctx->dsi = dsi;
> +	mipi_dsi_set_drvdata(dsi, ctx);
> +
> +	dsi->lanes = 4;
> +	dsi->format = MIPI_DSI_FMT_RGB888;
> +	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_HSE |
> +			  MIPI_DSI_MODE_NO_EOT_PACKET | MIPI_DSI_CLOCK_NON_CONTINUOUS;
> +
> +	ctx->panel.prepare_prev_first = true;
> +
> +	ctx->panel.backlight = ili7836a_create_backlight(dsi);
> +	if (IS_ERR(ctx->panel.backlight))
> +		return dev_err_probe(dev, PTR_ERR(ctx->panel.backlight),
> +				     "Failed to create backlight\n");
> +
> +	ret = devm_drm_panel_add(dev, &ctx->panel);
> +	if (ret)
> +		return ret;
> +
> +	return devm_mipi_dsi_attach(dev, dsi);
> +}
> +
> +static const struct of_device_id ili7836a_of_match[] = {
> +	{ .compatible = "retroidpocket,nova-panel", .data = &nova_desc },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, ili7836a_of_match);
> +
> +static struct mipi_dsi_driver ili7836a_driver = {
> +	.probe = ili7836a_probe,
> +	.driver = {
> +		.name = "panel-ili7836a-amoled",
> +		.of_match_table = ili7836a_of_match,
> +	},
> +};
> +module_mipi_dsi_driver(ili7836a_driver);
> +
> +MODULE_DESCRIPTION("DRM driver for ILI7836A DSI panels");
> +MODULE_LICENSE("GPL");
> 

Looks good

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

Thanks,
Neil