[PATCH v2 0/3] drm/panel: visionox-rm69299: Add backlight support and small fixes

[PATCH v2 0/3] drm/panel: visionox-rm69299: Add backlight support and small fixes

[Guido Günther]

This adds optional backlight support via DSI commands. If
a max_brightness is set in the panel description the backlight
is created.

While at that we fold in the already sent out clock fix and
a fix that prevents us from clearing all mode flags when we
only want HS mode.

Signed-off-by: Guido Günther <agx@sigxcpu.org>
---
Changes in v2:
- Add Fixes: to the first two commits to make backports simpler
- Collect Reviewed-by:, thanks Neil!
- Link to v1: https://lore.kernel.org/r/20250901-shift6mq-panel-v1-0-444b4abbfaea@sigxcpu.org

---
Guido Günther (3):
      drm/panel: visionox-rm69299: Fix clock frequency for SHIFT6mq
      drm/panel: visionox-rm69299: Don't clear all mode flags
      drm/panel: visionox-rm69299: Add backlight support

 drivers/gpu/drm/panel/panel-visionox-rm69299.c | 71 +++++++++++++++++++++++++-
 1 file changed, 69 insertions(+), 2 deletions(-)
---
base-commit: b320789d6883cc00ac78ce83bccbfe7ed58afcf0
change-id: 20250901-shift6mq-panel-959b3087ecd2

Best regards,
-- 
Guido Günther <agx@sigxcpu.org>

[PATCH v2 1/3] drm/panel: visionox-rm69299: Fix clock frequency for SHIFT6mq

[Guido Günther]

Make the clock frequency match what the sdm845 downstream kernel
uses. Otherwise the panel stays black.

Fixes: 783334f366b18 ("drm/panel: visionox-rm69299: support the variant found in the SHIFT6mq")
Signed-off-by: Guido Günther <agx@sigxcpu.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
---
 drivers/gpu/drm/panel/panel-visionox-rm69299.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panel/panel-visionox-rm69299.c b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
index 909c280eab1fb408a713d84051a1afbb252c45e8..e65697ce6f51c7d64b786da18cf44b16de5d6919 100644
--- a/drivers/gpu/drm/panel/panel-visionox-rm69299.c
+++ b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
@@ -247,7 +247,7 @@ static const struct drm_display_mode visionox_rm69299_1080x2248_60hz = {
 };
 
 static const struct drm_display_mode visionox_rm69299_1080x2160_60hz = {
-	.clock = 158695,
+	.clock = 149360,
 	.hdisplay = 1080,
 	.hsync_start = 1080 + 26,
 	.hsync_end = 1080 + 26 + 2,

-- 
2.51.0

[PATCH v2 2/3] drm/panel: visionox-rm69299: Don't clear all mode flags

[Guido Günther]

Don't clear all mode flags. We only want to maek sure we use HS mode
during unprepare.

Fixes: c7f66d32dd431 ("drm/panel: add support for rm69299 visionox panel")
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Guido Günther <agx@sigxcpu.org>
---
 drivers/gpu/drm/panel/panel-visionox-rm69299.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panel/panel-visionox-rm69299.c b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
index e65697ce6f51c7d64b786da18cf44b16de5d6919..2216d38366ea37368d15480f9d8a8ccbfe77ba3b 100644
--- a/drivers/gpu/drm/panel/panel-visionox-rm69299.c
+++ b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
@@ -192,7 +192,7 @@ static int visionox_rm69299_unprepare(struct drm_panel *panel)
 	struct visionox_rm69299 *ctx = panel_to_ctx(panel);
 	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
 
-	ctx->dsi->mode_flags = 0;
+	ctx->dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
 
 	mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
 

-- 
2.51.0

[PATCH v2 3/3] drm/panel: visionox-rm69299: Add backlight support

[Guido Günther]

The shift6mq's variant supports controlling the backlight via DSI
commands. Use that if a max_brightness is set in the device specific
data.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Guido Günther <agx@sigxcpu.org>
---
 drivers/gpu/drm/panel/panel-visionox-rm69299.c | 67 ++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-visionox-rm69299.c b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
index 2216d38366ea37368d15480f9d8a8ccbfe77ba3b..5e5ff6056c80e67a5bf8fe4911cdbc588db5d03b 100644
--- a/drivers/gpu/drm/panel/panel-visionox-rm69299.c
+++ b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
@@ -3,6 +3,7 @@
  * Copyright (c) 2019, The Linux Foundation. All rights reserved.
  */
 
+#include <linux/backlight.h>
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/property.h>
@@ -20,6 +21,8 @@ struct visionox_rm69299_panel_desc {
 	const struct drm_display_mode *mode;
 	const u8 *init_seq;
 	unsigned int init_seq_len;
+	int max_brightness;
+	int initial_brightness;
 };
 
 struct visionox_rm69299 {
@@ -285,6 +288,63 @@ static const struct drm_panel_funcs visionox_rm69299_drm_funcs = {
 	.get_modes = visionox_rm69299_get_modes,
 };
 
+static int visionox_rm69299_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(dsi, &brightness);
+	if (ret < 0)
+		return ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	return brightness;
+}
+
+static int visionox_rm69299_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(dsi, brightness);
+	if (ret < 0)
+		return ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	return 0;
+}
+
+static const struct backlight_ops visionox_rm69299_bl_ops = {
+	.update_status = visionox_rm69299_bl_update_status,
+	.get_brightness = visionox_rm69299_bl_get_brightness,
+};
+
+static struct backlight_device *
+visionox_rm69299_create_backlight(struct visionox_rm69299 *ctx)
+{
+	struct device *dev = &ctx->dsi->dev;
+	const struct backlight_properties props = {
+		.type = BACKLIGHT_RAW,
+		.brightness = ctx->desc->initial_brightness,
+		.max_brightness = ctx->desc->max_brightness,
+	};
+
+	if (!ctx->desc->max_brightness)
+		return 0;
+
+	return devm_backlight_device_register(dev, dev_name(dev), dev, ctx->dsi,
+					      &visionox_rm69299_bl_ops,
+					      &props);
+}
+
 static int visionox_rm69299_probe(struct mipi_dsi_device *dsi)
 {
 	struct device *dev = &dsi->dev;
@@ -316,6 +376,11 @@ static int visionox_rm69299_probe(struct mipi_dsi_device *dsi)
 		return PTR_ERR(ctx->reset_gpio);
 	}
 
+	ctx->panel.backlight = visionox_rm69299_create_backlight(ctx);
+	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);
 
 	dsi->lanes = 4;
@@ -353,6 +418,8 @@ const struct visionox_rm69299_panel_desc visionox_rm69299_shift_desc = {
 	.mode = &visionox_rm69299_1080x2160_60hz,
 	.init_seq = (const u8 *)visionox_rm69299_1080x2160_60hz_init_seq,
 	.init_seq_len = ARRAY_SIZE(visionox_rm69299_1080x2160_60hz_init_seq),
+	.max_brightness = 255,
+	.initial_brightness = 50,
 };
 
 static const struct of_device_id visionox_rm69299_of_match[] = {

-- 
2.51.0

Re: [PATCH v2 1/3] drm/panel: visionox-rm69299: Fix clock frequency for SHIFT6mq

[Dmitry Baryshkov]

On Sat, Sep 06, 2025 at 05:17:25PM +0200, Guido Günther wrote:
> Make the clock frequency match what the sdm845 downstream kernel
> uses. Otherwise the panel stays black.
> 
> Fixes: 783334f366b18 ("drm/panel: visionox-rm69299: support the variant found in the SHIFT6mq")
> Signed-off-by: Guido Günther <agx@sigxcpu.org>
> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
> ---
>  drivers/gpu/drm/panel/panel-visionox-rm69299.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panel/panel-visionox-rm69299.c b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
> index 909c280eab1fb408a713d84051a1afbb252c45e8..e65697ce6f51c7d64b786da18cf44b16de5d6919 100644
> --- a/drivers/gpu/drm/panel/panel-visionox-rm69299.c
> +++ b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
> @@ -247,7 +247,7 @@ static const struct drm_display_mode visionox_rm69299_1080x2248_60hz = {
>  };
>  
>  static const struct drm_display_mode visionox_rm69299_1080x2160_60hz = {
> -	.clock = 158695,
> +	.clock = 149360,

clock = (2160 + 8 + 4 + 4) * (1080 + 26 + 2 + 36) * 60 / 1000 ?

>  	.hdisplay = 1080,
>  	.hsync_start = 1080 + 26,
>  	.hsync_end = 1080 + 26 + 2,
> 
> -- 
> 2.51.0
> 

-- 
With best wishes
Dmitry

Re: [PATCH v2 1/3] drm/panel: visionox-rm69299: Fix clock frequency for SHIFT6mq

[Guido Günther]

Hi Dmitry,
On Sat, Sep 06, 2025 at 10:08:35PM +0300, Dmitry Baryshkov wrote:
> On Sat, Sep 06, 2025 at 05:17:25PM +0200, Guido Günther wrote:
> > Make the clock frequency match what the sdm845 downstream kernel
> > uses. Otherwise the panel stays black.
> > 
> > Fixes: 783334f366b18 ("drm/panel: visionox-rm69299: support the variant found in the SHIFT6mq")
> > Signed-off-by: Guido Günther <agx@sigxcpu.org>
> > Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
> > ---
> >  drivers/gpu/drm/panel/panel-visionox-rm69299.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/panel/panel-visionox-rm69299.c b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
> > index 909c280eab1fb408a713d84051a1afbb252c45e8..e65697ce6f51c7d64b786da18cf44b16de5d6919 100644
> > --- a/drivers/gpu/drm/panel/panel-visionox-rm69299.c
> > +++ b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
> > @@ -247,7 +247,7 @@ static const struct drm_display_mode visionox_rm69299_1080x2248_60hz = {
> >  };
> >  
> >  static const struct drm_display_mode visionox_rm69299_1080x2160_60hz = {
> > -	.clock = 158695,
> > +	.clock = 149360,
> 
> clock = (2160 + 8 + 4 + 4) * (1080 + 26 + 2 + 36) * 60 / 1000 ?

IIRC I was asked to use the resulting clock rather then the clock
formula in another driver a while back but I like that variant better
too, will change in v3.

Thanks,
 -- Guido

> 
> >  	.hdisplay = 1080,
> >  	.hsync_start = 1080 + 26,
> >  	.hsync_end = 1080 + 26 + 2,
> > 
> > -- 
> > 2.51.0
> > 
> 
> -- 
> With best wishes
> Dmitry
>