Re: [PATCH v5 2/5] drm/panel: add Novatek NT36850 panel driver

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

On 10/19/26 11:18, Dmitry Baryshkov wrote:
> Add support for the Truly WQHD dual-DSI command mode panel built around
> the Novatek NT36850, found on the display card for the Qualcomm SDM845
> and SM8150 HDK. The driver is based on panel-novatek-nt36523, the power
> and command sequences follow the vendor device tree.
> 
> Assisted-by: LLM
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/panel/Kconfig                 |  10 +
>   drivers/gpu/drm/panel/Makefile                |   1 +
>   drivers/gpu/drm/panel/panel-novatek-nt36850.c | 350 ++++++++++++++++++++++++++
>   3 files changed, 361 insertions(+)
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 53a1fc2913fe..869a5501e709 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -723,6 +723,16 @@ config DRM_PANEL_NOVATEK_NT36672E
>   	  LCD panel module. The panel has a resolution of 1080x2408 and uses 24 bit
>   	  RGB per pixel.
>   
> +config DRM_PANEL_NOVATEK_NT36850
> +	tristate "Novatek NT36850 panel driver"
> +	depends on OF
> +	depends on DRM_MIPI_DSI
> +	depends on BACKLIGHT_CLASS_DEVICE
> +	help
> +	  Say Y here if you want to enable support for the panels built
> +	  around the Novatek NT36850 display controller, such as some
> +	  Truly panels used in Qualcomm development kits.
> +
>   config DRM_PANEL_NOVATEK_NT37700F
>   	tristate "Novatek NT37700F DSI panel"
>   	depends on OF
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index f2c9c80a218f..8dd8eb7080cb 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -69,6 +69,7 @@ obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36532) += panel-novatek-nt36532.o
>   obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36536) += panel-novatek-nt36536.o
>   obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36672A) += panel-novatek-nt36672a.o
>   obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36672E) += panel-novatek-nt36672e.o
> +obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36850) += panel-novatek-nt36850.o
>   obj-$(CONFIG_DRM_PANEL_NOVATEK_NT37700F) += panel-novatek-nt37700f.o
>   obj-$(CONFIG_DRM_PANEL_NOVATEK_NT37801) += panel-novatek-nt37801.o
>   obj-$(CONFIG_DRM_PANEL_NOVATEK_NT39016) += panel-novatek-nt39016.o
> diff --git a/drivers/gpu/drm/panel/panel-novatek-nt36850.c b/drivers/gpu/drm/panel/panel-novatek-nt36850.c
> new file mode 100644
> index 000000000000..0d1eeba539db
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-novatek-nt36850.c
> @@ -0,0 +1,350 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Novatek NT36850 DriverIC panels driver
> + *
> + * Copyright (c) 2022, 2023 Jianhua Lu <lujianhua000@gmail.com>
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries
> + */
> +
> +#include <linux/backlight.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_graph.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <video/mipi_display.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>
> +
> +struct panel_info {
> +	struct drm_panel panel;
> +	struct mipi_dsi_device *dsi[2];
> +	const struct panel_desc *desc;
> +	enum drm_panel_orientation orientation;
> +
> +	struct gpio_desc *reset_gpio;
> +	struct regulator *vddio;
> +	struct regulator *avdd;
> +	struct regulator *avee;
> +};
> +
> +struct panel_desc {
> +	unsigned int bpc;
> +	unsigned int lanes;
> +	unsigned long mode_flags;
> +	enum mipi_dsi_pixel_format format;
> +
> +	const struct drm_display_mode *mode;
> +	int (*init_sequence)(struct panel_info *pinfo);
> +
> +	bool is_dual_dsi;
> +};
> +
> +static inline struct panel_info *to_panel_info(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct panel_info, panel);
> +}
> +
> +static int truly_wqhd_init_sequence(struct panel_info *pinfo)
> +{
> +	struct mipi_dsi_device *dsi0 = pinfo->dsi[0];
> +	struct mipi_dsi_device *dsi1 = pinfo->dsi[1];
> +	struct mipi_dsi_multi_context dsi_ctx = { .dsi = NULL };
> +
> +	mipi_dsi_dual_dcs_write_seq_multi(&dsi_ctx, dsi0, dsi1, 0xff, 0x10);
> +	mipi_dsi_dual_dcs_write_seq_multi(&dsi_ctx, dsi0, dsi1, 0xfb, 0x01);
> +	mipi_dsi_dual_dcs_write_seq_multi(&dsi_ctx, dsi0, dsi1,
> +					  MIPI_DCS_SET_ADDRESS_MODE, 0x00);
> +	mipi_dsi_dual(mipi_dsi_dcs_set_tear_on_multi, &dsi_ctx, dsi0, dsi1,
> +		      MIPI_DSI_DCS_TEAR_MODE_VBLANK);
> +	mipi_dsi_dual(mipi_dsi_dcs_set_tear_scanline_multi, &dsi_ctx, dsi0, dsi1,
> +		      1000);
> +	mipi_dsi_dual_dcs_write_seq_multi(&dsi_ctx, dsi0, dsi1,
> +					  MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
> +					  0xff);
> +	mipi_dsi_dual_dcs_write_seq_multi(&dsi_ctx, dsi0, dsi1,
> +					  MIPI_DCS_WRITE_CONTROL_DISPLAY,
> +					  0x2c);
> +	mipi_dsi_dual_dcs_write_seq_multi(&dsi_ctx, dsi0, dsi1,
> +					  MIPI_DCS_WRITE_POWER_SAVE, 0x01);
> +	mipi_dsi_dual_dcs_write_seq_multi(&dsi_ctx, dsi0, dsi1,
> +					  MIPI_DCS_EXIT_INVERT_MODE);
> +	mipi_dsi_usleep_range(&dsi_ctx, 10000, 11000);
> +	mipi_dsi_dual_dcs_write_seq_multi(&dsi_ctx, dsi0, dsi1, 0xbb, 0x10);
> +	mipi_dsi_dual(mipi_dsi_dcs_exit_sleep_mode_multi, &dsi_ctx, dsi0, dsi1);
> +	mipi_dsi_msleep(&dsi_ctx, 120);
> +	mipi_dsi_dual(mipi_dsi_dcs_set_display_on_multi, &dsi_ctx, dsi0, dsi1);
> +	mipi_dsi_msleep(&dsi_ctx, 120);
> +
> +	return dsi_ctx.accum_err;
> +}
> +
> +static const struct drm_display_mode truly_wqhd_mode = {
> +	.clock = (720 + 120 + 20 + 140) * 2 * (2560 + 8 + 4 + 20) * 60 / 1000,
> +	.hdisplay = 720 * 2,
> +	.hsync_start = (720 + 120) * 2,
> +	.hsync_end = (720 + 120 + 20) * 2,
> +	.htotal = (720 + 120 + 20 + 140) * 2,
> +	.vdisplay = 2560,
> +	.vsync_start = 2560 + 8,
> +	.vsync_end = 2560 + 8 + 4,
> +	.vtotal = 2560 + 8 + 4 + 20,
> +};
> +
> +static const struct panel_desc truly_wqhd_desc = {
> +	.mode = &truly_wqhd_mode,
> +	.bpc = 8,
> +	.lanes = 4,
> +	.format = MIPI_DSI_FMT_RGB888,
> +	.mode_flags = MIPI_DSI_CLOCK_NON_CONTINUOUS | MIPI_DSI_MODE_LPM,
> +	.init_sequence = truly_wqhd_init_sequence,
> +	.is_dual_dsi = true,
> +};
> +
> +static void nt36850_reset(struct panel_info *pinfo)
> +{
> +	gpiod_set_value_cansleep(pinfo->reset_gpio, 0);
> +	usleep_range(10000, 11000);
> +	gpiod_set_value_cansleep(pinfo->reset_gpio, 1);
> +	usleep_range(10000, 11000);
> +	gpiod_set_value_cansleep(pinfo->reset_gpio, 0);
> +	msleep(50);
> +}
> +
> +static int nt36850_prepare(struct drm_panel *panel)
> +{
> +	struct panel_info *pinfo = to_panel_info(panel);
> +	int ret;
> +
> +	ret = regulator_enable(pinfo->vddio);
> +	if (ret) {
> +		dev_err(panel->dev, "failed to enable vddio regulator: %d\n", ret);
> +		return ret;
> +	}
> +
> +	msleep(20);
> +
> +	ret = regulator_enable(pinfo->avdd);
> +	if (ret) {
> +		dev_err(panel->dev, "failed to enable avdd regulator: %d\n", ret);
> +		goto err_vddio;
> +	}
> +
> +	ret = regulator_enable(pinfo->avee);
> +	if (ret) {
> +		dev_err(panel->dev, "failed to enable avee regulator: %d\n", ret);
> +		goto err_avdd;
> +	}
> +
> +	msleep(20);
> +
> +	nt36850_reset(pinfo);
> +
> +	ret = pinfo->desc->init_sequence(pinfo);
> +	if (ret < 0) {
> +		dev_err(panel->dev, "failed to initialize panel: %d\n", ret);
> +		goto err_avee;
> +	}
> +
> +	return 0;
> +
> +err_avee:
> +	gpiod_set_value_cansleep(pinfo->reset_gpio, 1);
> +	regulator_disable(pinfo->avee);
> +err_avdd:
> +	regulator_disable(pinfo->avdd);
> +err_vddio:
> +	regulator_disable(pinfo->vddio);
> +
> +	return ret;
> +}
> +
> +static int nt36850_num_dsi_hosts(struct panel_info *pinfo)
> +{
> +	return pinfo->desc->is_dual_dsi ? 2 : 1;
> +}
> +
> +static int nt36850_disable(struct drm_panel *panel)
> +{
> +	struct panel_info *pinfo = to_panel_info(panel);
> +	struct mipi_dsi_multi_context dsi_ctx = { };
> +	int i;
> +
> +	for (i = 0; i < nt36850_num_dsi_hosts(pinfo); i++)
> +		pinfo->dsi[i]->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	for (i = 0; i < nt36850_num_dsi_hosts(pinfo); i++) {
> +		dsi_ctx.dsi = pinfo->dsi[i];
> +
> +		mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
> +	}
> +	mipi_dsi_msleep(&dsi_ctx, 120);
> +
> +	for (i = 0; i < nt36850_num_dsi_hosts(pinfo); i++) {
> +		dsi_ctx.dsi = pinfo->dsi[i];
> +
> +		mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx);
> +	}
> +	mipi_dsi_msleep(&dsi_ctx, 120);
> +
> +	for (i = 0; i < nt36850_num_dsi_hosts(pinfo); i++)
> +		pinfo->dsi[i]->mode_flags |= MIPI_DSI_MODE_LPM;
> +
> +	return dsi_ctx.accum_err;
> +}
> +
> +static int nt36850_unprepare(struct drm_panel *panel)
> +{
> +	struct panel_info *pinfo = to_panel_info(panel);
> +
> +	gpiod_set_value_cansleep(pinfo->reset_gpio, 1);
> +	regulator_disable(pinfo->avee);
> +	regulator_disable(pinfo->avdd);
> +	regulator_disable(pinfo->vddio);
> +
> +	return 0;
> +}
> +
> +static int nt36850_get_modes(struct drm_panel *panel,
> +			       struct drm_connector *connector)
> +{
> +	struct panel_info *pinfo = to_panel_info(panel);
> +
> +	connector->display_info.bpc = pinfo->desc->bpc;
> +
> +	return drm_connector_helper_get_modes_fixed(connector, pinfo->desc->mode);
> +}
> +
> +static enum drm_panel_orientation nt36850_get_orientation(struct drm_panel *panel)
> +{
> +	struct panel_info *pinfo = to_panel_info(panel);
> +
> +	return pinfo->orientation;
> +}
> +
> +static const struct drm_panel_funcs nt36850_panel_funcs = {
> +	.disable = nt36850_disable,
> +	.prepare = nt36850_prepare,
> +	.unprepare = nt36850_unprepare,
> +	.get_modes = nt36850_get_modes,
> +	.get_orientation = nt36850_get_orientation,
> +};
> +
> +static int nt36850_probe(struct mipi_dsi_device *dsi)
> +{
> +	struct device *dev = &dsi->dev;
> +	struct device_node *dsi1;
> +	struct mipi_dsi_host *dsi1_host;
> +	struct panel_info *pinfo;
> +	int i, ret;
> +
> +	pinfo = devm_drm_panel_alloc(dev, struct panel_info, panel,
> +				     &nt36850_panel_funcs,
> +				     DRM_MODE_CONNECTOR_DSI);
> +	if (IS_ERR(pinfo))
> +		return PTR_ERR(pinfo);
> +
> +	pinfo->vddio = devm_regulator_get(dev, "vddio");
> +	if (IS_ERR(pinfo->vddio))
> +		return dev_err_probe(dev, PTR_ERR(pinfo->vddio), "failed to get vddio regulator\n");
> +
> +	pinfo->avdd = devm_regulator_get(dev, "avdd");
> +	if (IS_ERR(pinfo->avdd))
> +		return dev_err_probe(dev, PTR_ERR(pinfo->avdd), "failed to get avdd regulator\n");
> +
> +	pinfo->avee = devm_regulator_get(dev, "avee");
> +	if (IS_ERR(pinfo->avee))
> +		return dev_err_probe(dev, PTR_ERR(pinfo->avee), "failed to get avee regulator\n");
> +
> +	pinfo->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(pinfo->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(pinfo->reset_gpio), "failed to get reset gpio\n");
> +
> +	pinfo->desc = of_device_get_match_data(dev);
> +	if (!pinfo->desc)
> +		return -ENODEV;
> +
> +	/* If the panel is dual dsi, register DSI1 */
> +	if (pinfo->desc->is_dual_dsi) {
> +		struct mipi_dsi_device_info dsi_info = {
> +			.type = "dsi-secondary",
> +		};
> +
> +		dsi1 = of_graph_get_remote_node(dsi->dev.of_node, 1, -1);
> +		if (!dsi1) {
> +			dev_err(dev, "cannot get secondary DSI node.\n");
> +			return -ENODEV;
> +		}
> +
> +		dsi1_host = of_find_mipi_dsi_host_by_node(dsi1);
> +		of_node_put(dsi1);
> +		if (!dsi1_host)
> +			return dev_err_probe(dev, -EPROBE_DEFER, "cannot get secondary DSI host\n");
> +
> +		pinfo->dsi[1] = devm_mipi_dsi_device_register_full(dev, dsi1_host, &dsi_info);
> +		if (IS_ERR(pinfo->dsi[1])) {
> +			dev_err(dev, "cannot get secondary DSI device\n");
> +			return PTR_ERR(pinfo->dsi[1]);
> +		}
> +	}
> +
> +	pinfo->dsi[0] = dsi;
> +	mipi_dsi_set_drvdata(dsi, pinfo);
> +
> +	ret = drm_of_get_panel_orientation(dev->of_node, &pinfo->orientation);
> +	if (ret < 0) {
> +		dev_err(dev, "%pOF: failed to get orientation %d\n", dev->of_node, ret);
> +		return ret;
> +	}
> +
> +	pinfo->panel.prepare_prev_first = true;
> +
> +	ret = drm_panel_of_backlight(&pinfo->panel);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to get backlight\n");
> +
> +	ret = devm_drm_panel_add(&dsi->dev, &pinfo->panel);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "can't add the panel\n");
> +
> +	for (i = 0; i < nt36850_num_dsi_hosts(pinfo); i++) {
> +		pinfo->dsi[i]->lanes = pinfo->desc->lanes;
> +		pinfo->dsi[i]->format = pinfo->desc->format;
> +		pinfo->dsi[i]->mode_flags = pinfo->desc->mode_flags;
> +
> +		ret = devm_mipi_dsi_attach(dev, pinfo->dsi[i]);
> +		if (ret < 0)
> +			return dev_err_probe(dev, ret, "cannot attach to DSI%d host.\n", i);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id nt36850_of_match[] = {
> +	{
> +		.compatible = "truly,wqhd60-nt36850",
> +		.data = &truly_wqhd_desc,
> +	},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, nt36850_of_match);
> +
> +static struct mipi_dsi_driver nt36850_driver = {
> +	.probe = nt36850_probe,
> +	.driver = {
> +		.name = "panel-novatek-nt36850",
> +		.of_match_table = nt36850_of_match,
> +	},
> +};
> +module_mipi_dsi_driver(nt36850_driver);
> +
> +MODULE_AUTHOR("Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>");
> +MODULE_DESCRIPTION("DRM driver for Novatek NT36850 based MIPI DSI panels");
> +MODULE_LICENSE("GPL");
> 

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

Thanks,
Neil