Re: [PATCH v2 2/3] drm: panel: Add Samsung S6E8FCO

[Yedaya Katsman]

On Tue, 24 Feb 2026 at 00:00, David Heidelberg <david@xxxxxxx> wrote:
>
> On 23/02/2026 21:26, Yedaya Katsman wrote:
> > Add driver for Samsung S6E8FCO DSI video mode panel, used in
> > Xiaomi Mi A3 mobile phone.
> >
> > Co-developed-by: Kamil Gołda <kamil.golda@xxxxxxxxxxxxxx>
> > Signed-off-by: Kamil Gołda <kamil.golda@xxxxxxxxxxxxxx>
> > Signed-off-by: Yedaya Katsman <yedaya.ka@xxxxxxxxx>
> > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
> > ---
> >   MAINTAINERS                                   |   1 +
> >   drivers/gpu/drm/panel/Kconfig                 |  12 ++
> >   drivers/gpu/drm/panel/Makefile                |   1 +
> >   drivers/gpu/drm/panel/panel-samsung-s6e8fco.c | 293 ++++++++++++++++++++++++++
> >   4 files changed, 307 insertions(+)
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 545d4cf68b9ac27765c7981e668e32cfecf3366b..238b5332eaf0e0cfb9834084e24671ccaee79939 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -8187,6 +8187,7 @@ DRM DRIVER FOR SAMSUNG S6E8FCO PANELS
> >   M:  Yedaya Katsman <yedaya.ka@xxxxxxxxx>
> >   S:  Maintained
> >   F:  Documentation/devicetree/bindings/display/panel/samsung,s6e8fco.yaml
> > +F:   drivers/gpu/drm/panel/panel-samsung-s6e8fco.c
> >
> >   DRM DRIVER FOR SAMSUNG SOFEF00 DDIC
> >   M:  David Heidelberg <david@xxxxxxx>
> > diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> > index 7a83804fedca1b688ce6fbe4295ec9009007e693..734640bb3f73c83e9273573aeb720ea1ba20862f 100644
> > --- a/drivers/gpu/drm/panel/Kconfig
> > +++ b/drivers/gpu/drm/panel/Kconfig
> > @@ -893,6 +893,18 @@ config DRM_PANEL_SAMSUNG_S6E8AA5X01_AMS561RA01
> >         ~5.6 inch AMOLED display, and the controller is driven by the MIPI
> >         DSI protocol with 4 lanes.
> >
> > +config DRM_PANEL_SAMSUNG_S6E8FCO
> > +     tristate "Samsung S6E8FCO DSI video mode panel"
> > +     depends on OF
> > +     depends on BACKLIGHT_CLASS_DEVICE
> > +     select DRM_MIPI_DSI
> > +     select VIDEOMODE_HELPERS
> > +     help
> > +       Say Y or M here if you want to enable support for the Samsung video
> > +       mode panel S6E8FCO. The panel has a 6.09 inch AMOLED display, with
>
> The S6E8.. is not panel, but Display Driver IC, the panel from the
> replacement parts is likely one of M1906F9SH M1906F9SI, thus I would say
> M1906F9.
>
> > +       a resolution of 720x1560.
> > +       Found in the Xiaomi Mi A3 smartphone (xiaomi-laurel).
> > +
> >   config DRM_PANEL_SAMSUNG_SOFEF00
> >       tristate "Samsung SOFEF00 DSI panel controller"
> >       depends on OF
> > diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> > index b9562a6fdcb38bfd0dfee9e8c11e16149ada4386..54eca60e5b57328ea94ed7880f4dead981f87fc1 100644
> > --- a/drivers/gpu/drm/panel/Makefile
> > +++ b/drivers/gpu/drm/panel/Makefile
> > @@ -91,6 +91,7 @@ obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E88A0_AMS427AP24) += panel-samsung-s6e88a0-ams4
> >   obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E88A0_AMS452EF01) += panel-samsung-s6e88a0-ams452ef01.o
> >   obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0) += panel-samsung-s6e8aa0.o
> >   obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA5X01_AMS561RA01) += panel-samsung-s6e8aa5x01-ams561ra01.o
> > +obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8FCO) += panel-samsung-s6e8fco.o
> >   obj-$(CONFIG_DRM_PANEL_SAMSUNG_SOFEF00) += panel-samsung-sofef00.o
> >   obj-$(CONFIG_DRM_PANEL_SEIKO_43WVF1G) += panel-seiko-43wvf1g.o
> >   obj-$(CONFIG_DRM_PANEL_SHARP_LQ079L1SX01) += panel-sharp-lq079l1sx01.o
> > diff --git a/drivers/gpu/drm/panel/panel-samsung-s6e8fco.c b/drivers/gpu/drm/panel/panel-samsung-s6e8fco.c
> > new file mode 100644
> > index 0000000000000000000000000000000000000000..7bbbe8af3e2eb9021ed7f555cb4ad2b0d7ea55ee
> > --- /dev/null
> > +++ b/drivers/gpu/drm/panel/panel-samsung-s6e8fco.c
> > @@ -0,0 +1,293 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +// Copyright (c) 2025 Kamil Gołda <kamil.golda@xxxxxxxxxxxxxx>
>
> nitpick: you can also drop copyright year from your copyright or update,
> up to you.
>
> > +// Generated with linux-mdss-dsi-panel-driver-generator from vendor device tree:
> > +// Copyright (c) 2025, The Linux Foundation. All rights reserved.
> > +
> > +#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/drm_mipi_dsi.h>
> > +#include <drm/drm_modes.h>
> > +#include <drm/drm_panel.h>
> > +#include <drm/drm_probe_helper.h>
> > +
> > +struct s6e8fco_samsungp {
> > +     struct drm_panel panel;
> > +     struct mipi_dsi_device *dsi;
> > +     struct regulator_bulk_data *supplies;
> > +     struct gpio_desc *reset_gpio;
> > +};
> > +
> > +static const struct regulator_bulk_data s6e8fco_samsungp_supplies[] = {
> > +     { .supply = "vddio" },
> > +     { .supply = "ldo" },
> > +     { .supply = "iovcc" },
> > +};
> > +
> > +static inline
> > +struct s6e8fco_samsungp *to_s6e8fco_samsungp(struct drm_panel *panel)
> > +{
> > +     return container_of_const(panel, struct s6e8fco_samsungp, panel);
> > +}
> > +
> > +static void s6e8fco_samsungp_reset(struct s6e8fco_samsungp *ctx)
> > +{
> > +     gpiod_set_value_cansleep(ctx->reset_gpio, 0);
> > +     usleep_range(12000, 13000);
> > +     gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> > +     usleep_range(2000, 3000);
> > +     gpiod_set_value_cansleep(ctx->reset_gpio, 0);
> > +     usleep_range(10000, 11000);
> > +}
> > +
> > +static int s6e8fco_samsungp_on(struct s6e8fco_samsungp *ctx)
> > +{
> > +     struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
> > +
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0x5a, 0x5a);
>
>    #define s6e3fc2x01_test_key_on_lvl3(ctx) \
>            mipi_dsi_dcs_write_seq_multi(ctx, 0xfc, 0x5a, 0x5a> +
> > +     mipi_dsi_dcs_set_display_brightness_multi(&dsi_ctx, 0x0000);
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY,
> > +                                  0x20);
> > +     mipi_dsi_dcs_exit_sleep_mode_multi(&dsi_ctx);
> > +     mipi_dsi_msleep(&dsi_ctx, 50);
> > +     mipi_dsi_dcs_set_display_on_multi(&dsi_ctx);
> > +
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb0, 0x04, 0xed);
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xed,
> > +                                  0xe4, 0x08, 0x96, 0xa4, 0x2a, 0x72, 0xe2,
> > +                                  0xca, 0x00);
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0xa5, 0xa5);
>
>    #define s6e3fc2x01_test_key_off_lvl3(ctx) \
>            mipi_dsi_dcs_write_seq_multi(ctx, 0xfc, 0xa5, 0xa5)
>
> etc. etc., check panel-samsung-s6e3fc2x01.c for example (and eventually
> other surrounding drivers) and try to de-mystify the writes as much as
> you can (ofc "reasonably" - as we don't have the datasheet).
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0x5a, 0x5a);
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0x5a, 0x5a);
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xe1, 0x93);
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb0, 0x05, 0xf4);
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf4, 0x03);
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xed, 0x01, 0x81, 0x04);
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0xa5, 0xa5);
> > +     mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0xa5, 0xa5);
> > +
> > +     return dsi_ctx.accum_err;
> > +}
> > +
> > +static int s6e8fco_samsungp_off(struct s6e8fco_samsungp *ctx)
> > +{
> > +     struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
> > +
> > +
> > +     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 s6e8fco_samsungp_prepare(struct drm_panel *panel)
> > +{
> > +     struct s6e8fco_samsungp *ctx = to_s6e8fco_samsungp(panel);
> > +     struct device *dev = &ctx->dsi->dev;
> > +     int ret;
> > +
> > +     ret = regulator_bulk_enable(ARRAY_SIZE(s6e8fco_samsungp_supplies), ctx->supplies);
> > +     if (ret < 0) {
> > +             dev_err(dev, "Failed to enable regulators: %d\n", ret);
> > +             return ret;
> > +     }
> > +
> > +     s6e8fco_samsungp_reset(ctx);
> > +
> > +     ret = s6e8fco_samsungp_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(s6e8fco_samsungp_supplies), ctx->supplies);
> > +             return ret;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int s6e8fco_samsungp_unprepare(struct drm_panel *panel)
> > +{
> > +     struct s6e8fco_samsungp *ctx = to_s6e8fco_samsungp(panel);
> > +     struct device *dev = &ctx->dsi->dev;
> > +     int ret;
> > +
> > +     ret = s6e8fco_samsungp_off(ctx);
> > +     if (ret < 0)
> > +             dev_err(dev, "Failed to un-initialize panel: %d\n", ret);
> > +
> > +     gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> > +     regulator_bulk_disable(ARRAY_SIZE(s6e8fco_samsungp_supplies), ctx->supplies);
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct drm_display_mode s6e8fco_samsungp_mode = {
>
> name the struct according to the panel, not (only) the DDIC.

Did that (in the next version I will send), changed the rest of
driver to be very S6E8FCO-M1906F9 specific as well.
>
> > +     .clock = (720 + 350 + 40 + 294) * (1560 + 17 + 2 + 5) * 60 / 1000,
> > +     .hdisplay = 720,
> > +     .hsync_start = 720 + 350,
> > +     .hsync_end = 720 + 350 + 40,
> > +     .htotal = 720 + 350 + 40 + 294,
> > +     .vdisplay = 1560,
> > +     .vsync_start = 1560 + 17,
> > +     .vsync_end = 1560 + 17 + 2,
> > +     .vtotal = 1560 + 17 + 2 + 5,
> > +     .width_mm = 65,
> > +     .height_mm = 140,
> > +     .type = DRM_MODE_TYPE_DRIVER,
> > +};
> > +
> > +static int s6e8fco_samsungp_get_modes(struct drm_panel *panel,
> > +                                   struct drm_connector *connector)
> > +{
> > +     return drm_connector_helper_get_modes_fixed(connector, &s6e8fco_samsungp_mode);
> > +}
> > +
> > +static const struct drm_panel_funcs s6e8fco_samsungp_panel_funcs = {
> > +     .prepare = s6e8fco_samsungp_prepare,
> > +     .unprepare = s6e8fco_samsungp_unprepare,
> > +     .get_modes = s6e8fco_samsungp_get_modes,
> > +};
> > +
> > +static int s6e8fco_samsungp_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 int s6e8fco_samsungp_bl_get_brightness(struct backlight_device *bl)
> > +{
> > +     struct mipi_dsi_device *dsi = bl_get_data(bl);
> > +     u16 brightness;
> > +     int ret;
> > +
> > +     dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
> > +
> > +     ret = mipi_dsi_dcs_get_display_brightness_large(dsi, &brightness);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     dsi->mode_flags |= MIPI_DSI_MODE_LPM;
> > +
> > +     return brightness;
> > +}
> > +
> > +static const struct backlight_ops s6e8fco_samsungp_bl_ops = {
> > +     .update_status = s6e8fco_samsungp_bl_update_status,
> > +     .get_brightness = s6e8fco_samsungp_bl_get_brightness,
> > +};
> > +
> > +static struct backlight_device *
> > +s6e8fco_samsungp_create_backlight(struct mipi_dsi_device *dsi)
> > +{
> > +     struct device *dev = &dsi->dev;
> > +     const struct backlight_properties props = {
> > +             .type = BACKLIGHT_RAW,
> > +             .brightness = 268,
>
> ~ 10% of brightness at boot? What is the scale? Shouldn't make sense to
> set it around 50%? (just asking)
This is just what was configured downstream, it looks bright enough for me
fwiw, I can change it if you want.

> > +             .max_brightness = 2047,
> > +     };
> > +
> > +     return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
> > +                                           &s6e8fco_samsungp_bl_ops, &props);
> > +}
> > +
> > +static int s6e8fco_samsungp_probe(struct mipi_dsi_device *dsi)
> > +{
> > +     struct device *dev = &dsi->dev;
> > +     struct s6e8fco_samsungp *ctx;
> > +     int ret;
> > +
> > +     ctx = devm_drm_panel_alloc(dev, struct s6e8fco_samsungp, panel,
> > +                                &s6e8fco_samsungp_panel_funcs,
> > +                                DRM_MODE_CONNECTOR_DSI);
> > +     if (IS_ERR(ctx))
> > +             return PTR_ERR(ctx);
> > +
> > +     ret = devm_regulator_bulk_get_const(dev,
> > +                                         ARRAY_SIZE(s6e8fco_samsungp_supplies),
> > +                                         s6e8fco_samsungp_supplies,
> > +                                         &ctx->supplies);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     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");
> > +
> > +     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_BURST |
> > +                       MIPI_DSI_CLOCK_NON_CONTINUOUS;
> > +
> > +     ctx->panel.prepare_prev_first = true;
> > +
> > +     ctx->panel.backlight = s6e8fco_samsungp_create_backlight(dsi);
> > +     if (IS_ERR(ctx->panel.backlight))
> > +             return dev_err_probe(dev, PTR_ERR(ctx->panel.backlight),
> > +                                  "Failed to create backlight\n");
> > +
> > +     drm_panel_add(&ctx->panel);
> > +
> > +     ret = mipi_dsi_attach(dsi);
> > +     if (ret < 0) {
> > +             drm_panel_remove(&ctx->panel);
> > +             return dev_err_probe(dev, ret, "Failed to attach to DSI host\n");
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static void s6e8fco_samsungp_remove(struct mipi_dsi_device *dsi)
> > +{
> > +     struct s6e8fco_samsungp *ctx = 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);
> > +
> > +     drm_panel_remove(&ctx->panel);
> > +}
> > +
> > +static const struct of_device_id s6e8fco_samsungp_of_match[] = {
> > +     { .compatible = "samsung,s6e8fco" },
>
> Optimally the compatible should reflect the panel used, eg something
> like samsung,s6e8fco-m1906f9 . It's possible there will be more panels
> using this DDIC, then this would make it much clearer.

Will do
> Happy to see another phone panel heading to mainline, thanks for your work!

Thanks for your review!
> David
>
> > +     { /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, s6e8fco_samsungp_of_match);
> > +
> > +static struct mipi_dsi_driver s6e8fco_samsungp_driver = {
> > +     .probe = s6e8fco_samsungp_probe,
> > +     .remove = s6e8fco_samsungp_remove,
> > +     .driver = {
> > +             .name = "panel-samsung-s6e8fco",
> > +             .of_match_table = s6e8fco_samsungp_of_match,
> > +     },
> > +};
> > +module_mipi_dsi_driver(s6e8fco_samsungp_driver);
> > +
> > +MODULE_AUTHOR("Kamil Gołda <kamil.golda@xxxxxxxxxxxxxx>");
> > +MODULE_DESCRIPTION("DRM driver for s6e8fco samsung amoled video mode dsi panel");
> > +MODULE_LICENSE("GPL");
> >
>
> --
> David Heidelberg
>

Thanks, Yedaya