Message-ID: <98bbdf17-4363-4dcc-a3f5-2450d27062b2@linaro.org>
Date: Wed, 29 Oct 2025 21:48:07 +0100
From: neil.armstrong@...aro.org
To: Langyan Ye <yelangyan@...qin.corp-partner.google.com>,
 jessica.zhang@....qualcomm.com, airlied@...il.com, simona@...ll.ch,
 maarten.lankhorst@...ux.intel.com, mripard@...nel.org, tzimmermann@...e.de,
 robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org,
 dianders@...omium.org
Cc: dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/2] drm/panel: Add driver for Ilitek IL79900A-based
 panels

On 10/22/25 14:46, Langyan Ye wrote:
> Add a DRM panel driver for the Ilitek IL79900A MIPI-DSI LCD controller.
> 
> The controller is used in panels such as the Tianma TL121BVMS07-00.
> It requires multiple power supplies (AVDD, AVEE, 1.8V logic), an enable
> GPIO, and a backlight device.
> 
> Signed-off-by: Langyan Ye <yelangyan@...qin.corp-partner.google.com>
> ---
>   drivers/gpu/drm/panel/panel-ilitek-il79900a.c | 358 ++++++++++++++++++
>   1 file changed, 358 insertions(+)
>   create mode 100644 drivers/gpu/drm/panel/panel-ilitek-il79900a.c
> 
> diff --git a/drivers/gpu/drm/panel/panel-ilitek-il79900a.c b/drivers/gpu/drm/panel/panel-ilitek-il79900a.c
> new file mode 100644
> index 000000000000..b2fa9b8860f7
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-ilitek-il79900a.c
> @@ -0,0 +1,358 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Panels based on the Ilitek IL79900A display controller.
> + *
> + * Based on drivers/gpu/drm/panel/panel-ilitek-ili9882t.c

It seems it could perfectly fit into panel-ilitek-ili9882t.c, could you try ?

Neil

> + */
> +#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_probe_helper.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_panel.h>
> +
> +#include <video/mipi_display.h>
> +
> +struct il79900a;
> +
> +/*
> + * Use this descriptor struct to describe different panels using the
> + * Ilitek IL79900A display controller.
> + */
> +struct panel_desc {
> +	const struct drm_display_mode *modes;
> +	unsigned int bpc;
> +	unsigned long mode_flags;
> +	enum mipi_dsi_pixel_format format;
> +	int (*init)(struct il79900a *boe);
> +	unsigned int lanes;
> +};
> +
> +struct il79900a {
> +	struct drm_panel base;
> +	struct mipi_dsi_device *dsi;
> +
> +	const struct panel_desc *desc;
> +
> +	enum drm_panel_orientation orientation;
> +	struct regulator *pp1800;
> +	struct regulator *avee;
> +	struct regulator *avdd;
> +	struct gpio_desc *enable_gpio;
> +};
> +
> +/* IL79900A-specific commands, add new commands as you decode them */
> +#define IL79900A_DCS_SWITCH_PAGE	0xFF
> +
> +#define il79900a_switch_page(ctx, page) \
> +	mipi_dsi_dcs_write_seq_multi(ctx, IL79900A_DCS_SWITCH_PAGE, \
> +				     0x5a, 0xa5, (page))
> +
> +static int tianma_il79900a_init(struct il79900a *ili)
> +{
> +	struct mipi_dsi_multi_context ctx = { .dsi = ili->dsi };
> +
> +	mipi_dsi_usleep_range(&ctx, 5000, 5100);
> +
> +	il79900a_switch_page(&ctx, 0x06);
> +	mipi_dsi_dcs_write_seq_multi(&ctx, 0x3e, 0x62);
> +
> +	il79900a_switch_page(&ctx, 0x02);
> +	mipi_dsi_dcs_write_seq_multi(&ctx, 0x1b, 0x20);
> +	mipi_dsi_dcs_write_seq_multi(&ctx, 0x5d, 0x00);
> +	mipi_dsi_dcs_write_seq_multi(&ctx, 0x5e, 0x40);
> +
> +	il79900a_switch_page(&ctx, 0x07);
> +	mipi_dsi_dcs_write_seq_multi(&ctx, 0X29, 0x00);
> +
> +	il79900a_switch_page(&ctx, 0x06);
> +	mipi_dsi_dcs_write_seq_multi(&ctx, 0x92, 0x22);
> +
> +	il79900a_switch_page(&ctx, 0x00);
> +	mipi_dsi_dcs_write_seq_multi(&ctx, MIPI_DCS_EXIT_SLEEP_MODE);
> +
> +	mipi_dsi_msleep(&ctx, 120);
> +
> +	mipi_dsi_dcs_write_seq_multi(&ctx, MIPI_DCS_SET_DISPLAY_ON);
> +
> +	mipi_dsi_msleep(&ctx, 80);
> +
> +	return 0;
> +};
> +
> +static inline struct il79900a *to_il79900a(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct il79900a, base);
> +}
> +
> +static int il79900a_enter_sleep_mode(struct mipi_dsi_multi_context *ctx)
> +{
> +	mipi_dsi_dcs_set_display_off_multi(ctx);
> +	mipi_dsi_dcs_enter_sleep_mode_multi(ctx);
> +	return ctx->accum_err;
> +}
> +
> +static int il79900a_disable(struct drm_panel *panel)
> +{
> +	struct il79900a *ili = to_il79900a(panel);
> +	struct mipi_dsi_multi_context ctx = { .dsi = ili->dsi };
> +	int ret;
> +
> +	il79900a_switch_page(&ctx, 0x00);
> +	if (ctx.accum_err)
> +		return ctx.accum_err;
> +
> +	ret = il79900a_enter_sleep_mode(&ctx);
> +	if (ret < 0) {
> +		dev_err(panel->dev, "failed to set panel off: %d\n", ret);
> +		return ret;
> +	}
> +
> +	mipi_dsi_msleep(&ctx, 150);
> +
> +	return 0;
> +}
> +
> +static int il79900a_unprepare(struct drm_panel *panel)
> +{
> +	struct il79900a *ili = to_il79900a(panel);
> +
> +	gpiod_set_value(ili->enable_gpio, 0);
> +	usleep_range(1000, 2000);
> +	regulator_disable(ili->avee);
> +	regulator_disable(ili->avdd);
> +	usleep_range(5000, 7000);
> +	regulator_disable(ili->pp1800);
> +
> +	return 0;
> +}
> +
> +static int il79900a_prepare(struct drm_panel *panel)
> +{
> +	struct il79900a *ili = to_il79900a(panel);
> +	int ret;
> +
> +	gpiod_set_value(ili->enable_gpio, 0);
> +	usleep_range(1000, 1500);
> +
> +	ret = regulator_enable(ili->pp1800);
> +	if (ret < 0)
> +		return ret;
> +
> +	usleep_range(3000, 5000);
> +
> +	ret = regulator_enable(ili->avdd);
> +	if (ret < 0)
> +		goto poweroff1v8;
> +	ret = regulator_enable(ili->avee);
> +	if (ret < 0)
> +		goto poweroffavdd;
> +
> +	usleep_range(10000, 11000);
> +
> +	// MIPI needs to keep the LP11 state before the lcm_reset pin is pulled high
> +	ret = mipi_dsi_dcs_nop(ili->dsi);
> +	if (ret < 0) {
> +		dev_err(&ili->dsi->dev, "Failed to send NOP: %d\n", ret);
> +		goto poweroff;
> +	}
> +	usleep_range(1000, 2000);
> +
> +	gpiod_set_value(ili->enable_gpio, 1);
> +	usleep_range(1000, 2000);
> +	gpiod_set_value(ili->enable_gpio, 0);
> +	usleep_range(10000, 11000);
> +	gpiod_set_value(ili->enable_gpio, 1);
> +	usleep_range(20000, 21000);
> +
> +	ret = ili->desc->init(ili);
> +	if (ret < 0)
> +		goto poweroff;
> +
> +	return 0;
> +
> +poweroff:
> +	gpiod_set_value(ili->enable_gpio, 0);
> +	regulator_disable(ili->avee);
> +poweroffavdd:
> +	regulator_disable(ili->avdd);
> +poweroff1v8:
> +	usleep_range(5000, 7000);
> +	regulator_disable(ili->pp1800);
> +
> +	return ret;
> +}
> +
> +static int il79900a_enable(struct drm_panel *panel)
> +{
> +	return 0;
> +}
> +
> +static const struct drm_display_mode tianma_il79900a_default_mode = {
> +	.clock = 264355,
> +	.hdisplay = 1600,
> +	.hsync_start = 1600 + 20,
> +	.hsync_end = 1600 + 20 + 4,
> +	.htotal = 1600 + 20 + 4 + 20,
> +	.vdisplay = 2560,
> +	.vsync_start = 2560 + 82,
> +	.vsync_end = 2560 + 82 + 2,
> +	.vtotal = 2560 + 82 + 2 + 36,
> +	.width_mm = 163,
> +	.height_mm = 260,
> +};
> +
> +static const struct panel_desc tianma_tl121bvms07_desc = {
> +	.modes = &tianma_il79900a_default_mode,
> +	.bpc = 8,
> +	.lanes = 3,
> +	.format = MIPI_DSI_FMT_RGB888,
> +	.mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
> +		      MIPI_DSI_MODE_LPM,
> +	.init = tianma_il79900a_init,
> +};
> +
> +static int il79900a_get_modes(struct drm_panel *panel,
> +			      struct drm_connector *connector)
> +{
> +	struct il79900a *ili = to_il79900a(panel);
> +	const struct drm_display_mode *m = ili->desc->modes;
> +	int num_modes;
> +
> +	num_modes = drm_connector_helper_get_modes_fixed(connector, m);
> +	if (num_modes <= 0)
> +		return 0;
> +
> +	connector->display_info.bpc = ili->desc->bpc;
> +
> +	return num_modes;
> +}
> +
> +static enum drm_panel_orientation il79900a_get_orientation(struct drm_panel *panel)
> +{
> +	struct il79900a *ili = to_il79900a(panel);
> +
> +	return ili->orientation;
> +}
> +
> +static const struct drm_panel_funcs il79900a_funcs = {
> +	.disable = il79900a_disable,
> +	.unprepare = il79900a_unprepare,
> +	.prepare = il79900a_prepare,
> +	.enable = il79900a_enable,
> +	.get_modes = il79900a_get_modes,
> +	.get_orientation = il79900a_get_orientation,
> +};
> +
> +static int il79900a_add(struct il79900a *ili)
> +{
> +	struct device *dev = &ili->dsi->dev;
> +	int err;
> +
> +	ili->avdd = devm_regulator_get(dev, "avdd");
> +	if (IS_ERR(ili->avdd))
> +		return PTR_ERR(ili->avdd);
> +
> +	ili->avee = devm_regulator_get(dev, "avee");
> +	if (IS_ERR(ili->avee))
> +		return PTR_ERR(ili->avee);
> +
> +	ili->pp1800 = devm_regulator_get(dev, "pp1800");
> +	if (IS_ERR(ili->pp1800))
> +		return PTR_ERR(ili->pp1800);
> +
> +	ili->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
> +	if (IS_ERR(ili->enable_gpio)) {
> +		dev_err(dev, "cannot get reset-gpios %ld\n",
> +			PTR_ERR(ili->enable_gpio));
> +		return PTR_ERR(ili->enable_gpio);
> +	}
> +
> +	gpiod_set_value(ili->enable_gpio, 0);
> +
> +	drm_panel_init(&ili->base, dev, &il79900a_funcs,
> +		       DRM_MODE_CONNECTOR_DSI);
> +	err = of_drm_get_panel_orientation(dev->of_node, &ili->orientation);
> +	if (err < 0) {
> +		dev_err(dev, "%pOF: failed to get orientation %d\n", dev->of_node, err);
> +		return err;
> +	}
> +
> +	err = drm_panel_of_backlight(&ili->base);
> +	if (err)
> +		return err;
> +
> +	ili->base.funcs = &il79900a_funcs;
> +	ili->base.dev = &ili->dsi->dev;
> +
> +	drm_panel_add(&ili->base);
> +
> +	return 0;
> +}
> +
> +static int il79900a_probe(struct mipi_dsi_device *dsi)
> +{
> +	struct il79900a *ili;
> +	int ret;
> +	const struct panel_desc *desc;
> +
> +	ili = devm_kzalloc(&dsi->dev, sizeof(*ili), GFP_KERNEL);
> +	if (!ili)
> +		return -ENOMEM;
> +
> +	desc = of_device_get_match_data(&dsi->dev);
> +	dsi->lanes = desc->lanes;
> +	dsi->format = desc->format;
> +	dsi->mode_flags = desc->mode_flags;
> +	ili->desc = desc;
> +	ili->dsi = dsi;
> +	ret = il79900a_add(ili);
> +	if (ret < 0)
> +		return ret;
> +
> +	mipi_dsi_set_drvdata(dsi, ili);
> +
> +	ret = mipi_dsi_attach(dsi);
> +	if (ret)
> +		drm_panel_remove(&ili->base);
> +
> +	return ret;
> +}
> +
> +static void il79900a_remove(struct mipi_dsi_device *dsi)
> +{
> +	struct il79900a *ili = mipi_dsi_get_drvdata(dsi);
> +	int ret;
> +
> +	ret = mipi_dsi_detach(dsi);
> +	if (ret < 0)
> +		dev_err(&dsi->dev, "failed to detach from DSI host: %d\n", ret);
> +
> +	if (ili->base.dev)
> +		drm_panel_remove(&ili->base);
> +}
> +
> +static const struct of_device_id il79900a_of_match[] = {
> +	{ .compatible = "tianma,tl121bvms07-00", .data = &tianma_tl121bvms07_desc },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, il79900a_of_match);
> +
> +static struct mipi_dsi_driver il79900a_driver = {
> +	.driver = {
> +		.name = "panel-il79900a",
> +		.of_match_table = il79900a_of_match,
> +	},
> +	.probe = il79900a_probe,
> +	.remove = il79900a_remove,
> +};
> +module_mipi_dsi_driver(il79900a_driver);
> +
> +MODULE_AUTHOR("Langyan Ye <yelangyan@...qin.corp-partner.google.com>");
> +MODULE_DESCRIPTION("Ilitek IL79900A-based panels driver");
> +MODULE_LICENSE("GPL");

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