Re: [PATCH 2/4] drm/panel: Add driver for Novatek NT37705 panel

Hi

Am 15.05.26 um 16:31 schrieb Luca Weiss:
> On Fri May 8, 2026 at 10:06 AM CEST, Thomas Zimmermann wrote:
>> Hi
>>
>> Am 01.05.26 um 15:52 schrieb Luca Weiss:
>>> Add support for the 2484x1116 AMOLED panel from BOE (BJ631JHM-T71-D900)
>>> bundled with a NT37705 driver IC, as found on the Fairphone (Gen. 6)
>>> smartphone.
>>>
>>> The panel can also be configured in 10-bit (RGB101010) mode, however
>>> currently it's configured in 8-bit (RGB888) since there's some issues in
>>> the Qualcomm DPU driver when driving this panel in 10-bit.
>>>
>>> Signed-off-by: Luca Weiss <[email protected]>
>>> ---
>>>    drivers/gpu/drm/panel/Kconfig                 |  11 +
>>>    drivers/gpu/drm/panel/Makefile                |   1 +
>>>    drivers/gpu/drm/panel/panel-novatek-nt37705.c | 413 ++++++++++++++++++++++++++
>>>    3 files changed, 425 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
>>> index 979109c27b9b..59ab3f29d8ef 100644
>>> --- a/drivers/gpu/drm/panel/Kconfig
>>> +++ b/drivers/gpu/drm/panel/Kconfig
>>> @@ -624,6 +624,17 @@ config DRM_PANEL_NOVATEK_NT37700F
>>>    	  Say Y here if you want to enable support for Novatek NT37700F DSI
>>>    	  panel module. The panel has a resolution of 1080x2160.
>>>    
>>> +config DRM_PANEL_NOVATEK_NT37705
>>> +	tristate "Novatek NT37705-based DSI panel"
>>> +	depends on OF
>>> +	depends on DRM_MIPI_DSI
>>> +	depends on BACKLIGHT_CLASS_DEVICE
>>> +	select DRM_KMS_HELPER
>>> +	help
>>> +	  Say Y here if you want to enable support for Novatek NT37705-based
>>> +	  display panels, such as the one found in the The Fairphone (Gen. 6)
>> Duplicate 'the'
> Marketing really wanted to have it be "The Fairphone". Will change and
> make it saner.

How about "as the one found in Gen. 6 of The Fairphone." ?



>
>>> +	  smartphone.
>>> +
>>>    config DRM_PANEL_NOVATEK_NT37801
>>>    	tristate "Novatek NT37801/NT37810 AMOLED DSI panel"
>>>    	depends on OF
>>> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
>>> index 0d694acbfbb6..94639bc58ca8 100644
>>> --- a/drivers/gpu/drm/panel/Makefile
>>> +++ b/drivers/gpu/drm/panel/Makefile
>>> @@ -61,6 +61,7 @@ obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36523) += panel-novatek-nt36523.o
>>>    obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36672A) += panel-novatek-nt36672a.o
>>>    obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36672E) += panel-novatek-nt36672e.o
>>>    obj-$(CONFIG_DRM_PANEL_NOVATEK_NT37700F) += panel-novatek-nt37700f.o
>>> +obj-$(CONFIG_DRM_PANEL_NOVATEK_NT37705) += panel-novatek-nt37705.o
>>>    obj-$(CONFIG_DRM_PANEL_NOVATEK_NT37801) += panel-novatek-nt37801.o
>>>    obj-$(CONFIG_DRM_PANEL_NOVATEK_NT39016) += panel-novatek-nt39016.o
>>>    obj-$(CONFIG_DRM_PANEL_MANTIX_MLAF057WE51) += panel-mantix-mlaf057we51.o
>>> diff --git a/drivers/gpu/drm/panel/panel-novatek-nt37705.c b/drivers/gpu/drm/panel/panel-novatek-nt37705.c
>>> new file mode 100644
>>> index 000000000000..27bd8072ccd1
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/panel/panel-novatek-nt37705.c
>>> @@ -0,0 +1,413 @@
>>> +// SPDX-License-Identifier: GPL-2.0-only
>>> +/*
>>> + * Generated with linux-mdss-dsi-panel-driver-generator from vendor device tree.
>>> + * Copyright (c) 2026 Luca Weiss <[email protected]>
>>> + */
>>> +
>>> +#include <linux/backlight.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/gpio/consumer.h>
>>> +#include <linux/mod_devicetable.h>
>>> +#include <linux/module.h>
>>> +#include <linux/regulator/consumer.h>
>>> +
>>> +#include <video/mipi_display.h>
>>> +
>>> +#include <drm/display/drm_dsc.h>
>>> +#include <drm/display/drm_dsc_helper.h>
>> IIRC this requires
>>
>>    select DRM_DISPLAY_DSC_HELPER
>>
>> in the Kconfig. Maybe double-check.
> Will check. Always difficult to figure out the proper dependencies in a
> fully-featured defconfig build.
>
>>> +#include <drm/drm_mipi_dsi.h>
>>> +#include <drm/drm_modes.h>
>>> +#include <drm/drm_panel.h>
>>> +#include <drm/drm_probe_helper.h>
>>> +
>>> +struct nt37705_panel {
>>> +	struct drm_panel panel;
>>> +	struct mipi_dsi_device *dsi;
>>> +	struct drm_dsc_config dsc;
>>> +	struct regulator_bulk_data *supplies;
>>> +	struct gpio_desc *reset_gpio;
>>> +};
>>> +
>>> +static const struct regulator_bulk_data nt37705_supplies[] = {
>>> +	{ .supply = "vddio" },
>>> +	{ .supply = "dvdd" },
>>> +	{ .supply = "vci" },
>>> +};
>>> +
>>> +static inline struct nt37705_panel *to_nt37705_panel(struct drm_panel *panel)
>>> +{
>>> +	return container_of_const(panel, struct nt37705_panel, panel);
>> Either just use container_of or build something that respects the
>> input's const-ness.
> I really don't get what you mean here? Why is container_of_const() bad
> here?

Because nothing is const here. It looks like an oversight or as if 
something should be const.

>
>>> +}
>>> +
>>> +static void nt37705_reset(struct nt37705_panel *ctx)
>>> +{
>>> +	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
>>> +	usleep_range(10000, 11000);
>>> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
>>> +	usleep_range(5000, 6000);
>>> +	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
>>> +	usleep_range(10000, 11000);
>>> +}
>>> +
>>> +static int nt37705_on(struct nt37705_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, 0xf0,
>>> +				     0x55, 0xaa, 0x52, 0x08, 0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x1b);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba, 0x18);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x1c);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
>>> +				     0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00,
>>> +				     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
>>> +				     0x00, 0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x2c);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
>>> +				     0x00, 0x01, 0x01, 0x01, 0x00, 0x05, 0x05,
>>> +				     0x05, 0x00, 0x05, 0x05, 0x05, 0x00, 0x00,
>>> +				     0x00, 0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x3c);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
>>> +				     0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x0b,
>>> +				     0x0b, 0x00, 0x00, 0x0b, 0x0b, 0x00, 0x00,
>>> +				     0x00, 0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x4c);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
>>> +				     0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
>>> +				     0x1d, 0x00, 0x00, 0x00, 0x1d, 0x00, 0x00,
>>> +				     0x00, 0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x5c);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
>>> +				     0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
>>> +				     0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
>>> +				     0x01, 0x01);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x6c);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
>>> +				     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x0b,
>>> +				     0x77, 0x77, 0x00, 0x00, 0x0b, 0x00, 0x1d,
>>> +				     0x00, 0x1d);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x7c);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
>>> +				     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x0b,
>>> +				     0x77, 0x77, 0x00, 0x00, 0x0b, 0x00, 0x1d,
>>> +				     0x00, 0x1d);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x8c);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
>>> +				     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
>>> +				     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
>>> +				     0x00, 0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x9c);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
>>> +				     0x11, 0x11, 0x20, 0x02, 0x00, 0x03, 0x00,
>>> +				     0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0xa4);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba, 0x00, 0xc0, 0x40, 0x08);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0xa8);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
>>> +				     0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,
>>> +				     0x22);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0xb0);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
>>> +				     0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,
>>> +				     0x22);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0,
>>> +				     0x55, 0xaa, 0x52, 0x08, 0x01);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x05);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xc5, 0x15, 0x15, 0x15, 0xdd);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0,
>>> +				     0x55, 0xaa, 0x52, 0x08, 0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x0e);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb5, 0x32);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0,
>>> +				     0x55, 0xaa, 0x52, 0x00, 0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0xaa, 0x55, 0xa5, 0x80);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x19);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf2, 0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x1a);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf4, 0x55);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x11);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf8, 0x01, 0x7f);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x2d);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf8, 0x01, 0x20);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0xaa, 0x55, 0xa5, 0x81);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x05);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfe, 0x3c);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x02);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf9, 0x04);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x1e);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfb, 0x0f);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x0f);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf5, 0x20);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x0d);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfb, 0x80);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0xaa, 0x55, 0xa5, 0x83);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x12);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfe, 0x41);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x13);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfd, 0x21);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0xaa, 0x55, 0xa5, 0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x35);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY,
>>> +				     0x20);
>>> +	mipi_dsi_dcs_set_column_address_multi(&dsi_ctx, 0x0000, 0x045b);
>>> +	mipi_dsi_dcs_set_page_address_multi(&dsi_ctx, 0x0000, 0x09b3);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_SET_GAMMA_CURVE, 0x00);
>>> +	mipi_dsi_dcs_set_display_brightness_multi(&dsi_ctx, 0xbb0d);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x04);
>>> +	mipi_dsi_dcs_set_display_brightness_multi(&dsi_ctx, 0xfe0f);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x81, 0x01, 0x19);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x03, 0x01);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x90, 0x03, 0x03);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x91,
>>> +				     0x89, 0x28, 0x00, 0x0c, 0xd2, 0x00, 0x02,
>>> +				     0x2f, 0x01, 0x18, 0x00, 0x07, 0x09, 0x75,
>>> +				     0x08, 0x34, 0x10, 0xf0);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x2f, 0x02);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x5a, 0x01);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x2f, 0x30);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6d, 0x00);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x11, 0x00);
>>> +	mipi_dsi_msleep(&dsi_ctx, 120);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x29, 0x00);
>>> +	mipi_dsi_msleep(&dsi_ctx, 22);
>>> +
>>> +	return dsi_ctx.accum_err;
>>> +}
>>> +
>>> +static int nt37705_off(struct nt37705_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, 0x28, 0x00);
>>> +	mipi_dsi_msleep(&dsi_ctx, 20);
>>> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x10, 0x00);
>>> +	mipi_dsi_msleep(&dsi_ctx, 120);
>>> +
>>> +	return dsi_ctx.accum_err;
>>> +}
>>> +
>>> +static int nt37705_prepare(struct drm_panel *panel)
>>> +{
>>> +	struct nt37705_panel *ctx = to_nt37705_panel(panel);
>>> +	struct device *dev = &ctx->dsi->dev;
>>> +	struct drm_dsc_picture_parameter_set pps;
>>> +	int ret;
>>> +
>>> +	ret = regulator_bulk_enable(ARRAY_SIZE(nt37705_supplies), ctx->supplies);
>>> +	if (ret < 0) {
>> Common style is to check for errors with
>>
>>     if (ret)
>>
>> Here and everywhere else.
> At least for regulator_bulk_enable() "ret < 0" is actually more popular
> than just "ret".
>
> Kernel doc says "Return: 0 on success or a negative error number on
> failure." so a positive integer should in theory never happen so they're
> equivalent.
>
> (git grep -h -A2 regulator_bulk_enable | grep if | sed 's|^[ \t]\+||' | sed 's| {$||' | sort | uniq -c)

It's just nitpicking, not a blocker.

Best regards
Thomas

>
> Thanks for the review!
>
> Regards
> Luca

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)