[PATCH 0/5] Panel rotation patches

[PATCH 0/5] Panel rotation patches

[Derek Basehore]

This adds the plumbing for reading panel rotation from the devicetree
and sets up adding a panel property for the panel orientation on
Mediatek SoCs when a rotation is present.

Derek Basehore (5):
  drm/panel: Add helper for reading DT rotation
  dt-bindings: display/panel: Expand rotation documentation
  drm/panel: Add attach/detach callbacks
  drm/connector: Split out orientation quirk detection
  drm/mtk: add panel orientation property

 .../bindings/display/panel/panel.txt          | 32 +++++++++++
 drivers/gpu/drm/drm_connector.c               | 16 ++----
 drivers/gpu/drm/drm_panel.c                   | 55 +++++++++++++++++++
 drivers/gpu/drm/i915/vlv_dsi.c                | 13 +++--
 drivers/gpu/drm/mediatek/mtk_dsi.c            |  8 +++
 include/drm/drm_connector.h                   |  2 +-
 include/drm/drm_panel.h                       | 11 ++++
 7 files changed, 120 insertions(+), 17 deletions(-)

-- 
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[PATCH 1/5] drm/panel: Add helper for reading DT rotation

[Derek Basehore]

This adds a helper function for reading the rotation (panel
orientation) from the device tree.

Signed-off-by: Derek Basehore <dbasehore@chromium.org>
---
 drivers/gpu/drm/drm_panel.c | 41 +++++++++++++++++++++++++++++++++++++
 include/drm/drm_panel.h     |  7 +++++++
 2 files changed, 48 insertions(+)

diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index dbd5b873e8f2..3b689ce4a51a 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -172,6 +172,47 @@ struct drm_panel *of_drm_find_panel(const struct device_node *np)
 	return ERR_PTR(-EPROBE_DEFER);
 }
 EXPORT_SYMBOL(of_drm_find_panel);
+
+/**
+ * of_drm_get_panel_orientation - look up the rotation of the panel using a
+ * device tree node
+ * @np: device tree node of the panel
+ * @orientation: orientation enum to be filled in
+ *
+ * Looks up the rotation of a panel in the device tree. The rotation in the
+ * device tree is counter clockwise.
+ *
+ * Return: 0 when a valid rotation value (0, 90, 180, or 270) is read or the
+ * rotation property doesn't exist. -EERROR otherwise.
+ */
+int of_drm_get_panel_orientation(const struct device_node *np, int *orientation)
+{
+	int rotation, ret;
+
+	ret = of_property_read_u32(np, "rotation", &rotation);
+	if (ret == -EINVAL) {
+		/* Don't return an error if there's no rotation property. */
+		*orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
+		return 0;
+	}
+
+	if (ret < 0)
+		return ret;
+
+	if (rotation == 0)
+		*orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;
+	else if (rotation == 90)
+		*orientation = DRM_MODE_PANEL_ORIENTATION_RIGHT_UP;
+	else if (rotation == 180)
+		*orientation = DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP;
+	else if (rotation == 270)
+		*orientation = DRM_MODE_PANEL_ORIENTATION_LEFT_UP;
+	else
+		return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL(of_drm_get_panel_orientation);
 #endif
 
 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index 8c738c0e6e9f..13631b2efbaa 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -197,11 +197,18 @@ int drm_panel_detach(struct drm_panel *panel);
 
 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
 struct drm_panel *of_drm_find_panel(const struct device_node *np);
+int of_drm_get_panel_orientation(const struct device_node *np,
+				 int *orientation);
 #else
 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
 {
 	return ERR_PTR(-ENODEV);
 }
+int of_drm_get_panel_orientation(const struct device_node *np,
+				 int *orientation)
+{
+	return -ENODEV;
+}
 #endif
 
 #endif
-- 
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[PATCH 2/5] dt-bindings: display/panel: Expand rotation documentation

[Derek Basehore]

This adds to the rotation documentation to explain how drivers should
use the property and gives an example of the property in a devicetree
node.

Signed-off-by: Derek Basehore <dbasehore@chromium.org>
---
 .../bindings/display/panel/panel.txt          | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/panel.txt b/Documentation/devicetree/bindings/display/panel/panel.txt
index e2e6867852b8..f35d62d933fc 100644
--- a/Documentation/devicetree/bindings/display/panel/panel.txt
+++ b/Documentation/devicetree/bindings/display/panel/panel.txt
@@ -2,3 +2,35 @@ Common display properties
 -------------------------
 
 - rotation:	Display rotation in degrees counter clockwise (0,90,180,270)
+
+Property read from the device tree using of of_drm_get_panel_orientation
+
+The panel driver may apply the rotation at the TCON level, which will
+make the panel look like it isn't rotated to the kernel and any other
+software.
+
+If not, a panel orientation property should be added through the SoC
+vendor DRM code using the drm_connector_init_panel_orientation_property
+function.
+
+Example:
+	panel: panel@0 {
+		compatible = "boe,himax8279d8p";
+		reg = <0>;
+		enable-gpios = <&pio 45 0>;
+		pp33-gpios = <&pio 35 0>;
+		pp18-gpios = <&pio 36 0>;
+		pinctrl-names = "default", "state_3300mv", "state_1800mv";
+		pinctrl-0 = <&panel_pins_default>;
+		pinctrl-1 = <&panel_pins_3300mv>;
+		pinctrl-2 = <&panel_pins_1800mv>;
+		backlight = <&backlight_lcd0>;
+		rotation = <180>;
+		status = "okay";
+
+		port {
+			panel_in: endpoint {
+				remote-endpoint = <&dsi_out>;
+			};
+		};
+	};
-- 
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[PATCH 3/5] drm/panel: Add attach/detach callbacks

[Derek Basehore]

This adds the attach/detach callbacks. These are for setting up
internal state for the connector/panel pair that can't be done at
probe (since the connector doesn't exist) and which don't need to be
repeatedly done for every get/modes, prepare, or enable callback.
Values such as the panel orientation, and display size can be filled
in for the connector.

Signed-off-by: Derek Basehore <dbasehore@chromium.org>
---
 drivers/gpu/drm/drm_panel.c | 14 ++++++++++++++
 include/drm/drm_panel.h     |  4 ++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index 3b689ce4a51a..72f67678d9d5 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -104,12 +104,23 @@ EXPORT_SYMBOL(drm_panel_remove);
  */
 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
 {
+	int ret;
+
 	if (panel->connector)
 		return -EBUSY;
 
 	panel->connector = connector;
 	panel->drm = connector->dev;
 
+	if (panel->funcs->attach) {
+		ret = panel->funcs->attach(panel);
+		if (ret < 0) {
+			panel->connector = NULL;
+			panel->drm = NULL;
+			return ret;
+		}
+	}
+
 	return 0;
 }
 EXPORT_SYMBOL(drm_panel_attach);
@@ -128,6 +139,9 @@ EXPORT_SYMBOL(drm_panel_attach);
  */
 int drm_panel_detach(struct drm_panel *panel)
 {
+	if (panel->funcs->detach)
+		panel->funcs->detach(panel);
+
 	panel->connector = NULL;
 	panel->drm = NULL;
 
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index 13631b2efbaa..e136e3a3c996 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -37,6 +37,8 @@ struct display_timing;
  * struct drm_panel_funcs - perform operations on a given panel
  * @disable: disable panel (turn off back light, etc.)
  * @unprepare: turn off panel
+ * @detach: detach panel->connector (clear internal state, etc.)
+ * @attach: attach panel->connector (update internal state, etc.)
  * @prepare: turn on panel and perform set up
  * @enable: enable panel (turn on back light, etc.)
  * @get_modes: add modes to the connector that the panel is attached to and
@@ -70,6 +72,8 @@ struct display_timing;
 struct drm_panel_funcs {
 	int (*disable)(struct drm_panel *panel);
 	int (*unprepare)(struct drm_panel *panel);
+	void (*detach)(struct drm_panel *panel);
+	int (*attach)(struct drm_panel *panel);
 	int (*prepare)(struct drm_panel *panel);
 	int (*enable)(struct drm_panel *panel);
 	int (*get_modes)(struct drm_panel *panel);
-- 
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[PATCH 4/5] drm/connector: Split out orientation quirk detection

[Derek Basehore]

This removes the orientation quirk detection from the code to add
an orientation property to a panel. This is used only for legacy x86
systems, yet we'd like to start using this on device tree systems
where quirk detection like this is not needed.

Signed-off-by: Derek Basehore <dbasehore@chromium.org>
---
 drivers/gpu/drm/drm_connector.c | 16 ++++------------
 drivers/gpu/drm/i915/vlv_dsi.c  | 13 +++++++++----
 include/drm/drm_connector.h     |  2 +-
 3 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index e17586aaa80f..58a09b65028b 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -1894,31 +1894,23 @@ EXPORT_SYMBOL(drm_connector_set_vrr_capable_property);
  * drm_connector_init_panel_orientation_property -
  *	initialize the connecters panel_orientation property
  * @connector: connector for which to init the panel-orientation property.
- * @width: width in pixels of the panel, used for panel quirk detection
- * @height: height in pixels of the panel, used for panel quirk detection
  *
  * This function should only be called for built-in panels, after setting
  * connector->display_info.panel_orientation first (if known).
  *
- * This function will check for platform specific (e.g. DMI based) quirks
- * overriding display_info.panel_orientation first, then if panel_orientation
- * is not DRM_MODE_PANEL_ORIENTATION_UNKNOWN it will attach the
- * "panel orientation" property to the connector.
+ * This function will check if the panel_orientation is not
+ * DRM_MODE_PANEL_ORIENTATION_UNKNOWN. If not, it will attach the "panel
+ * orientation" property to the connector.
  *
  * Returns:
  * Zero on success, negative errno on failure.
  */
 int drm_connector_init_panel_orientation_property(
-	struct drm_connector *connector, int width, int height)
+	struct drm_connector *connector)
 {
 	struct drm_device *dev = connector->dev;
 	struct drm_display_info *info = &connector->display_info;
 	struct drm_property *prop;
-	int orientation_quirk;
-
-	orientation_quirk = drm_get_panel_orientation_quirk(width, height);
-	if (orientation_quirk != DRM_MODE_PANEL_ORIENTATION_UNKNOWN)
-		info->panel_orientation = orientation_quirk;
 
 	if (info->panel_orientation == DRM_MODE_PANEL_ORIENTATION_UNKNOWN)
 		return 0;
diff --git a/drivers/gpu/drm/i915/vlv_dsi.c b/drivers/gpu/drm/i915/vlv_dsi.c
index bfe2891eac37..113129996530 100644
--- a/drivers/gpu/drm/i915/vlv_dsi.c
+++ b/drivers/gpu/drm/i915/vlv_dsi.c
@@ -1650,6 +1650,7 @@ static void intel_dsi_add_properties(struct intel_connector *connector)
 
 	if (connector->panel.fixed_mode) {
 		u32 allowed_scalers;
+		int orientation;
 
 		allowed_scalers = BIT(DRM_MODE_SCALE_ASPECT) | BIT(DRM_MODE_SCALE_FULLSCREEN);
 		if (!HAS_GMCH(dev_priv))
@@ -1660,12 +1661,16 @@ static void intel_dsi_add_properties(struct intel_connector *connector)
 
 		connector->base.state->scaling_mode = DRM_MODE_SCALE_ASPECT;
 
-		connector->base.display_info.panel_orientation =
-			vlv_dsi_get_panel_orientation(connector);
-		drm_connector_init_panel_orientation_property(
-				&connector->base,
+		orientation = drm_get_panel_orientation_quirk(
 				connector->panel.fixed_mode->hdisplay,
 				connector->panel.fixed_mode->vdisplay);
+		if (orientation != DRM_MODE_PANEL_ORIENTATION_UNKNOWN)
+			connector->display_info.panel_orientation = orientation;
+		else
+			connector->display_info.panel_orientation =
+				intel_dsi_get_panel_orientation(connector);
+
+		drm_connector_init_panel_orientation_property(&connector->base);
 	}
 }
 
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 47e749b74e5f..c2992f7a0dd5 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -1370,7 +1370,7 @@ void drm_connector_set_link_status_property(struct drm_connector *connector,
 void drm_connector_set_vrr_capable_property(
 		struct drm_connector *connector, bool capable);
 int drm_connector_init_panel_orientation_property(
-	struct drm_connector *connector, int width, int height);
+	struct drm_connector *connector);
 int drm_connector_attach_max_bpc_property(struct drm_connector *connector,
 					  int min, int max);
 
-- 
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[PATCH 5/5] drm/mtk: add panel orientation property

[Derek Basehore]

This inits the panel orientation property for the mediatek dsi driver
if the panel orientation (connector.display_info.panel_orientation) is
not DRM_MODE_PANEL_ORIENTATION_UNKNOWN.

Signed-off-by: Derek Basehore <dbasehore@chromium.org>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 4a0b9150a7bb..08ffdc7526dd 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -782,10 +782,18 @@ static int mtk_dsi_create_connector(struct drm_device *drm, struct mtk_dsi *dsi)
 			DRM_ERROR("Failed to attach panel to drm\n");
 			goto err_connector_cleanup;
 		}
+
+		ret = drm_connector_init_panel_orientation_property(&dsi->conn);
+		if (ret) {
+			DRM_ERROR("Failed to init panel orientation\n");
+			goto err_panel_detach;
+		}
 	}
 
 	return 0;
 
+err_panel_detach:
+	drm_panel_detach(dsi->panel);
 err_connector_cleanup:
 	drm_connector_cleanup(&dsi->conn);
 	return ret;
-- 
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Re: [PATCH 5/5] drm/mtk: add panel orientation property

[CK Hu]

Hi, Derek:

On Mon, 2019-06-10 at 17:22 -0700, Derek Basehore wrote:
> This inits the panel orientation property for the mediatek dsi driver
> if the panel orientation (connector.display_info.panel_orientation) is
> not DRM_MODE_PANEL_ORIENTATION_UNKNOWN.
> 

Looks good to me,

Acked-by: CK Hu <ck.hu@mediatek.com>

> Signed-off-by: Derek Basehore <dbasehore@chromium.org>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 4a0b9150a7bb..08ffdc7526dd 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -782,10 +782,18 @@ static int mtk_dsi_create_connector(struct drm_device *drm, struct mtk_dsi *dsi)
>  			DRM_ERROR("Failed to attach panel to drm\n");
>  			goto err_connector_cleanup;
>  		}
> +
> +		ret = drm_connector_init_panel_orientation_property(&dsi->conn);
> +		if (ret) {
> +			DRM_ERROR("Failed to init panel orientation\n");
> +			goto err_panel_detach;
> +		}
>  	}
>  
>  	return 0;
>  
> +err_panel_detach:
> +	drm_panel_detach(dsi->panel);
>  err_connector_cleanup:
>  	drm_connector_cleanup(&dsi->conn);
>  	return ret;



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[PATCH v2 0/5] Panel rotation patches

[Derek Basehore]

This adds the plumbing for reading panel rotation from the devicetree
and sets up adding a panel property for the panel orientation on
Mediatek SoCs when a rotation is present.

v2 changes:
fixed build errors in i915

Derek Basehore (5):
  drm/panel: Add helper for reading DT rotation
  dt-bindings: display/panel: Expand rotation documentation
  drm/panel: Add attach/detach callbacks
  drm/connector: Split out orientation quirk detection
  drm/mtk: add panel orientation property

 .../bindings/display/panel/panel.txt          | 32 +++++++++++
 drivers/gpu/drm/drm_connector.c               | 16 ++----
 drivers/gpu/drm/drm_panel.c                   | 55 +++++++++++++++++++
 drivers/gpu/drm/i915/vlv_dsi.c                | 13 +++--
 drivers/gpu/drm/mediatek/mtk_dsi.c            |  8 +++
 include/drm/drm_connector.h                   |  2 +-
 include/drm/drm_panel.h                       | 11 ++++
 7 files changed, 120 insertions(+), 17 deletions(-)

-- 
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[PATCH 2/5] dt-bindings: display/panel: Expand rotation documentation

[Derek Basehore]

This adds to the rotation documentation to explain how drivers should
use the property and gives an example of the property in a devicetree
node.

Signed-off-by: Derek Basehore <dbasehore@chromium.org>
---
 .../bindings/display/panel/panel.txt          | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/panel.txt b/Documentation/devicetree/bindings/display/panel/panel.txt
index e2e6867852b8..f35d62d933fc 100644
--- a/Documentation/devicetree/bindings/display/panel/panel.txt
+++ b/Documentation/devicetree/bindings/display/panel/panel.txt
@@ -2,3 +2,35 @@ Common display properties
 -------------------------
 
 - rotation:	Display rotation in degrees counter clockwise (0,90,180,270)
+
+Property read from the device tree using of of_drm_get_panel_orientation
+
+The panel driver may apply the rotation at the TCON level, which will
+make the panel look like it isn't rotated to the kernel and any other
+software.
+
+If not, a panel orientation property should be added through the SoC
+vendor DRM code using the drm_connector_init_panel_orientation_property
+function.
+
+Example:
+	panel: panel@0 {
+		compatible = "boe,himax8279d8p";
+		reg = <0>;
+		enable-gpios = <&pio 45 0>;
+		pp33-gpios = <&pio 35 0>;
+		pp18-gpios = <&pio 36 0>;
+		pinctrl-names = "default", "state_3300mv", "state_1800mv";
+		pinctrl-0 = <&panel_pins_default>;
+		pinctrl-1 = <&panel_pins_3300mv>;
+		pinctrl-2 = <&panel_pins_1800mv>;
+		backlight = <&backlight_lcd0>;
+		rotation = <180>;
+		status = "okay";
+
+		port {
+			panel_in: endpoint {
+				remote-endpoint = <&dsi_out>;
+			};
+		};
+	};
-- 
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Re: [PATCH 2/5] dt-bindings: display/panel: Expand rotation documentation

[Rob Herring]

On Mon, Jun 10, 2019 at 10:03 PM Derek Basehore <dbasehore@chromium.org> wrote:
>
> This adds to the rotation documentation to explain how drivers should
> use the property and gives an example of the property in a devicetree
> node.
>
> Signed-off-by: Derek Basehore <dbasehore@chromium.org>
> ---
>  .../bindings/display/panel/panel.txt          | 32 +++++++++++++++++++
>  1 file changed, 32 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/display/panel/panel.txt b/Documentation/devicetree/bindings/display/panel/panel.txt
> index e2e6867852b8..f35d62d933fc 100644
> --- a/Documentation/devicetree/bindings/display/panel/panel.txt
> +++ b/Documentation/devicetree/bindings/display/panel/panel.txt
> @@ -2,3 +2,35 @@ Common display properties
>  -------------------------
>
>  - rotation:    Display rotation in degrees counter clockwise (0,90,180,270)
> +
> +Property read from the device tree using of of_drm_get_panel_orientation

Don't put kernel specifics into bindings.

> +
> +The panel driver may apply the rotation at the TCON level, which will

What's TCON? Something Mediatek specific IIRC.

> +make the panel look like it isn't rotated to the kernel and any other
> +software.
> +
> +If not, a panel orientation property should be added through the SoC
> +vendor DRM code using the drm_connector_init_panel_orientation_property
> +function.

The 'rotation' property should be defined purely based on how the
panel is mounted relative to a device's orientation. If the display
pipeline has some ability to handle rotation, that's a feature of the
display pipeline and not the panel.

> +
> +Example:

This file is a collection of common properties. It shouldn't have an
example especially as this example is mostly non-common properties.

> +       panel: panel@0 {
> +               compatible = "boe,himax8279d8p";
> +               reg = <0>;
> +               enable-gpios = <&pio 45 0>;

> +               pp33-gpios = <&pio 35 0>;
> +               pp18-gpios = <&pio 36 0>;

BTW, are these upstream because they look like GPIO controlled
supplies which we model with gpio-regulator binding typically.

> +               pinctrl-names = "default", "state_3300mv", "state_1800mv";
> +               pinctrl-0 = <&panel_pins_default>;
> +               pinctrl-1 = <&panel_pins_3300mv>;
> +               pinctrl-2 = <&panel_pins_1800mv>;
> +               backlight = <&backlight_lcd0>;
> +               rotation = <180>;
> +               status = "okay";
> +
> +               port {
> +                       panel_in: endpoint {
> +                               remote-endpoint = <&dsi_out>;
> +                       };
> +               };
> +       };
> --
> 2.22.0.rc2.383.gf4fbbf30c2-goog
>

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Re: [PATCH 2/5] dt-bindings: display/panel: Expand rotation documentation

[dbasehore .]

On Tue, Jun 11, 2019 at 8:25 AM Rob Herring <robh+dt@kernel.org> wrote:
>
> On Mon, Jun 10, 2019 at 10:03 PM Derek Basehore <dbasehore@chromium.org> wrote:
> >
> > This adds to the rotation documentation to explain how drivers should
> > use the property and gives an example of the property in a devicetree
> > node.
> >
> > Signed-off-by: Derek Basehore <dbasehore@chromium.org>
> > ---
> >  .../bindings/display/panel/panel.txt          | 32 +++++++++++++++++++
> >  1 file changed, 32 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/display/panel/panel.txt b/Documentation/devicetree/bindings/display/panel/panel.txt
> > index e2e6867852b8..f35d62d933fc 100644
> > --- a/Documentation/devicetree/bindings/display/panel/panel.txt
> > +++ b/Documentation/devicetree/bindings/display/panel/panel.txt
> > @@ -2,3 +2,35 @@ Common display properties
> >  -------------------------
> >
> >  - rotation:    Display rotation in degrees counter clockwise (0,90,180,270)
> > +
> > +Property read from the device tree using of of_drm_get_panel_orientation
>
> Don't put kernel specifics into bindings.

Will remove that. I'll clean up the documentation to indicate that
this binding creates a panel orientation property unless the rotation
is handled in the Timing Controller on the panel if that sounds fine.

>
> > +
> > +The panel driver may apply the rotation at the TCON level, which will
>
> What's TCON? Something Mediatek specific IIRC.

The TCON is the Timing controller, which is on the panel. Every panel
has one. I'll add to the doc that the TCON is in the panel, etc.

>
> > +make the panel look like it isn't rotated to the kernel and any other
> > +software.
> > +
> > +If not, a panel orientation property should be added through the SoC
> > +vendor DRM code using the drm_connector_init_panel_orientation_property
> > +function.
>
> The 'rotation' property should be defined purely based on how the
> panel is mounted relative to a device's orientation. If the display
> pipeline has some ability to handle rotation, that's a feature of the
> display pipeline and not the panel.

This is how the panel orientation property is already handled in the
kernel. See drivers/gpu/drm/i915/vlv_dsi.c for more details.

>
> > +
> > +Example:
>
> This file is a collection of common properties. It shouldn't have an
> example especially as this example is mostly non-common properties.

Just copied one of our DTS entries that uses the property. I'll remove
everything under compatible except for rotation and status.

>
> > +       panel: panel@0 {
> > +               compatible = "boe,himax8279d8p";
> > +               reg = <0>;
> > +               enable-gpios = <&pio 45 0>;
>
> > +               pp33-gpios = <&pio 35 0>;
> > +               pp18-gpios = <&pio 36 0>;
>
> BTW, are these upstream because they look like GPIO controlled
> supplies which we model with gpio-regulator binding typically.

The boe,himax8279 driver was sent upstream, but it doesn't appear to
be merged. I'll look into it on that thread.

>
> > +               pinctrl-names = "default", "state_3300mv", "state_1800mv";
> > +               pinctrl-0 = <&panel_pins_default>;
> > +               pinctrl-1 = <&panel_pins_3300mv>;
> > +               pinctrl-2 = <&panel_pins_1800mv>;
> > +               backlight = <&backlight_lcd0>;
> > +               rotation = <180>;
> > +               status = "okay";
> > +
> > +               port {
> > +                       panel_in: endpoint {
> > +                               remote-endpoint = <&dsi_out>;
> > +                       };
> > +               };
> > +       };
> > --
> > 2.22.0.rc2.383.gf4fbbf30c2-goog
> >

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Re: [PATCH 2/5] dt-bindings: display/panel: Expand rotation documentation

[Rob Herring]

On Tue, Jun 11, 2019 at 4:02 PM dbasehore . <dbasehore@chromium.org> wrote:
>
> On Tue, Jun 11, 2019 at 8:25 AM Rob Herring <robh+dt@kernel.org> wrote:
> >
> > On Mon, Jun 10, 2019 at 10:03 PM Derek Basehore <dbasehore@chromium.org> wrote:
> > >
> > > This adds to the rotation documentation to explain how drivers should
> > > use the property and gives an example of the property in a devicetree
> > > node.
> > >
> > > Signed-off-by: Derek Basehore <dbasehore@chromium.org>
> > > ---
> > >  .../bindings/display/panel/panel.txt          | 32 +++++++++++++++++++
> > >  1 file changed, 32 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/display/panel/panel.txt b/Documentation/devicetree/bindings/display/panel/panel.txt
> > > index e2e6867852b8..f35d62d933fc 100644
> > > --- a/Documentation/devicetree/bindings/display/panel/panel.txt
> > > +++ b/Documentation/devicetree/bindings/display/panel/panel.txt
> > > @@ -2,3 +2,35 @@ Common display properties
> > >  -------------------------
> > >
> > >  - rotation:    Display rotation in degrees counter clockwise (0,90,180,270)
> > > +
> > > +Property read from the device tree using of of_drm_get_panel_orientation
> >
> > Don't put kernel specifics into bindings.
>
> Will remove that. I'll clean up the documentation to indicate that
> this binding creates a panel orientation property unless the rotation
> is handled in the Timing Controller on the panel if that sounds fine.

Even if the timing ctrlr handles it, don't you still need to know what
the native orientation is?

> > > +
> > > +The panel driver may apply the rotation at the TCON level, which will
> >
> > What's TCON? Something Mediatek specific IIRC.
>
> The TCON is the Timing controller, which is on the panel. Every panel
> has one. I'll add to the doc that the TCON is in the panel, etc.
>
> >
> > > +make the panel look like it isn't rotated to the kernel and any other
> > > +software.
> > > +
> > > +If not, a panel orientation property should be added through the SoC
> > > +vendor DRM code using the drm_connector_init_panel_orientation_property
> > > +function.
> >
> > The 'rotation' property should be defined purely based on how the
> > panel is mounted relative to a device's orientation. If the display
> > pipeline has some ability to handle rotation, that's a feature of the
> > display pipeline and not the panel.
>
> This is how the panel orientation property is already handled in the
> kernel. See drivers/gpu/drm/i915/vlv_dsi.c for more details.

The point is your description is all about the kernel. This is a
binding which is not kernel specific.

> > > +
> > > +Example:
> >
> > This file is a collection of common properties. It shouldn't have an
> > example especially as this example is mostly non-common properties.
>
> Just copied one of our DTS entries that uses the property. I'll remove
> everything under compatible except for rotation and status.

Just remove the example or add what you want to the "boe,himax8279d8p"
binding doc. We are moving towards examples being compiled and
validated, so incomplete ones won't work.

Rob

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Re: [PATCH 2/5] dt-bindings: display/panel: Expand rotation documentation

[dbasehore .]

On Thu, Jun 13, 2019 at 5:52 AM Rob Herring <robh+dt@kernel.org> wrote:
>
> On Tue, Jun 11, 2019 at 4:02 PM dbasehore . <dbasehore@chromium.org> wrote:
> >
> > On Tue, Jun 11, 2019 at 8:25 AM Rob Herring <robh+dt@kernel.org> wrote:
> > >
> > > On Mon, Jun 10, 2019 at 10:03 PM Derek Basehore <dbasehore@chromium.org> wrote:
> > > >
> > > > This adds to the rotation documentation to explain how drivers should
> > > > use the property and gives an example of the property in a devicetree
> > > > node.
> > > >
> > > > Signed-off-by: Derek Basehore <dbasehore@chromium.org>
> > > > ---
> > > >  .../bindings/display/panel/panel.txt          | 32 +++++++++++++++++++
> > > >  1 file changed, 32 insertions(+)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/display/panel/panel.txt b/Documentation/devicetree/bindings/display/panel/panel.txt
> > > > index e2e6867852b8..f35d62d933fc 100644
> > > > --- a/Documentation/devicetree/bindings/display/panel/panel.txt
> > > > +++ b/Documentation/devicetree/bindings/display/panel/panel.txt
> > > > @@ -2,3 +2,35 @@ Common display properties
> > > >  -------------------------
> > > >
> > > >  - rotation:    Display rotation in degrees counter clockwise (0,90,180,270)
> > > > +
> > > > +Property read from the device tree using of of_drm_get_panel_orientation
> > >
> > > Don't put kernel specifics into bindings.
> >
> > Will remove that. I'll clean up the documentation to indicate that
> > this binding creates a panel orientation property unless the rotation
> > is handled in the Timing Controller on the panel if that sounds fine.
>
> Even if the timing ctrlr handles it, don't you still need to know what
> the native orientation is?

Not really. For all intents and purposes, the orientation of the panel
has changed.

>
> > > > +
> > > > +The panel driver may apply the rotation at the TCON level, which will
> > >
> > > What's TCON? Something Mediatek specific IIRC.
> >
> > The TCON is the Timing controller, which is on the panel. Every panel
> > has one. I'll add to the doc that the TCON is in the panel, etc.
> >
> > >
> > > > +make the panel look like it isn't rotated to the kernel and any other
> > > > +software.
> > > > +
> > > > +If not, a panel orientation property should be added through the SoC
> > > > +vendor DRM code using the drm_connector_init_panel_orientation_property
> > > > +function.
> > >
> > > The 'rotation' property should be defined purely based on how the
> > > panel is mounted relative to a device's orientation. If the display
> > > pipeline has some ability to handle rotation, that's a feature of the
> > > display pipeline and not the panel.
> >
> > This is how the panel orientation property is already handled in the
> > kernel. See drivers/gpu/drm/i915/vlv_dsi.c for more details.
>
> The point is your description is all about the kernel. This is a
> binding which is not kernel specific.

Ah, I see. I thought you were saying what the implementation should be.

>
> > > > +
> > > > +Example:
> > >
> > > This file is a collection of common properties. It shouldn't have an
> > > example especially as this example is mostly non-common properties.
> >
> > Just copied one of our DTS entries that uses the property. I'll remove
> > everything under compatible except for rotation and status.
>
> Just remove the example or add what you want to the "boe,himax8279d8p"
> binding doc. We are moving towards examples being compiled and
> validated, so incomplete ones won't work.

Ok, will do.

>
> Rob

Thanks for the quick reviews.

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