[PATCH v2 0/5] drm/panel: simple: Add mode support to devicetree

[PATCH v2 0/5] drm/panel: simple: Add mode support to devicetree

[Sean Paul]

Hey all,
Here's a set which allows us to add an "override" mode to the simple
panel dt node. The override mode can be used for devices for which the
typical display timing is not sufficient, yet the overriding mode should
not be applied across the entire platform.

An example of this (and the motivation) is the Chromebook Plus (kevin).
If the sharp panel on this laptop is run at the mode advertised in the
datasheet (and what is currently in mainline), it creates interference
with the touch digitizer. To fix this, we need to run the pixel clock at
a slightly higher rate (which we can do by increasing the back porches).
This "fix" should not be used on other rockchip devices using this panel
since they might not encounter the same interference.

If an override mode is present, it will be checked against the panel's
display_timing range. When validated, it will be exposed as the
preferred mode along with the 'typical' modes generated from the panel's
display_timing.

This set is based on Linus' master to pick up the edp support in
rk3399-gru-kevin.dts.

Thanks,

Sean

Sean Paul (5):
  dt-bindings: Add headings to simple-panel bindings
  dt-bindings: Add display-timing subnode to simple-panel
  drm/panel: simple: Add ability to override typical timing
  drm/panel: simple: Use display_timing for lq123p1jx31
  arm64: dts: rockchip: Specify override mode for kevin panel

 .../bindings/display/panel/simple-panel.txt        |  36 +++++++
 arch/arm64/boot/dts/rockchip/rk3399-gru-kevin.dts  |  16 ++++
 drivers/gpu/drm/panel/panel-simple.c               | 104 ++++++++++++++++++---
 3 files changed, 141 insertions(+), 15 deletions(-)

-- 
2.16.0.rc1.238.g530d649a79-goog

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[PATCH v2 1/5] dt-bindings: Add headings to simple-panel bindings

[Sean Paul]

In preparation for a new subnode section in a follow-on patch, add
explicit headings to the existings sections for simple-panel.

Changes in v2:
 - Added

Cc: Doug Anderson <dianders@chromium.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Jeffy Chen <jeffy.chen@rock-chips.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Stéphane Marchesin <marcheu@chromium.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: devicetree@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
 Documentation/devicetree/bindings/display/panel/simple-panel.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/simple-panel.txt b/Documentation/devicetree/bindings/display/panel/simple-panel.txt
index 16d8ff088b7d..45a457ad38f0 100644
--- a/Documentation/devicetree/bindings/display/panel/simple-panel.txt
+++ b/Documentation/devicetree/bindings/display/panel/simple-panel.txt
@@ -1,4 +1,8 @@
 Simple display panel
+====================
+
+panel node
+----------
 
 Required properties:
 - power-supply: See panel-common.txt
-- 
2.16.0.rc1.238.g530d649a79-goog

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[PATCH v2 2/5] dt-bindings: Add display-timing subnode to simple-panel

[Sean Paul]

This patch adds a new subnode to simple-panel allowing us to override
the typical timing expressed in the panel's display_timing.

Changes in v2:
 - Split out the binding into a new patch (Rob)
 - display-timings is a new section (Rob)
 - Use the full display-timings subnode instead of picking the timing
   out (Rob/Thierry)

Cc: Doug Anderson <dianders@chromium.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Jeffy Chen <jeffy.chen@rock-chips.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Stéphane Marchesin <marcheu@chromium.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: devicetree@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
 .../bindings/display/panel/simple-panel.txt        | 32 ++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/simple-panel.txt b/Documentation/devicetree/bindings/display/panel/simple-panel.txt
index 45a457ad38f0..9717b9b79d98 100644
--- a/Documentation/devicetree/bindings/display/panel/simple-panel.txt
+++ b/Documentation/devicetree/bindings/display/panel/simple-panel.txt
@@ -12,6 +12,24 @@ Optional properties:
 - enable-gpios: GPIO pin to enable or disable the panel
 - backlight: phandle of the backlight device attached to the panel
 
+display-timings subnode
+-----------------------
+
+This optional subnode is for devices which require a mode differing from the
+panel's "typical" display timing as programmed in the simple-panel driver.
+Overriding the driver mode must only be done in the following scenario:
+ - The restrictions motivating the override cannot be applied to the platform's
+   display driver (ie: it must be specific to the device not the platform)
+ - The panel must not have a fixed mode attributed to it in the driver
+ - The panel must provide at list one display_timing range by which the override
+   mode can be validated against
+ - The override mode will use the 'typ' values from the display-timings subnode
+ - You must provide all required properties for the display-timings subnode
+
+Format information on the display-timings subnode can be found in
+display-timing.txt.
+
+
 Example:
 
 	panel: panel {
@@ -22,4 +40,18 @@ Example:
 		enable-gpios = <&gpio 90 0>;
 
 		backlight = <&backlight>;
+
+		display-timings {
+			timing0: override {
+				clock-frequency = <266604720>;
+				hactive = <2400>;
+				hfront-porch = <48>;
+				hback-porch = <84>;
+				hsync-len = <32>;
+				vactive = <1600>;
+				vfront-porch = <3>;
+				vback-porch = <120>;
+				vsync-len = <10>;
+			};
+		};
 	};
-- 
2.16.0.rc1.238.g530d649a79-goog

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[PATCH v2 4/5] drm/panel: simple: Use display_timing for lq123p1jx31

[Sean Paul]

Convert the sharp lq123p1jx31 from using a fixed mode to specifying a
display timing with min/typ/max values. This allows us to capture the
timings set forth in the datasheet as well as the additional values that
we've cleared with the display vendor to avoid interference with the
digitizer on the Samsung Chromebook Plus (kevin).

A follow-on patch will specify the override mode for kevin devices.

Changes in v2:
 - None

Cc: Doug Anderson <dianders@chromium.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Jeffy Chen <jeffy.chen@rock-chips.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Stéphane Marchesin <marcheu@chromium.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: devicetree@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
 drivers/gpu/drm/panel/panel-simple.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index c1635b35f97e..0de176a6a041 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -1816,23 +1816,22 @@ static const struct panel_desc sharp_lq101k1ly04 = {
 	.bus_format = MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA,
 };
 
-static const struct drm_display_mode sharp_lq123p1jx31_mode = {
-	.clock = 252750,
-	.hdisplay = 2400,
-	.hsync_start = 2400 + 48,
-	.hsync_end = 2400 + 48 + 32,
-	.htotal = 2400 + 48 + 32 + 80,
-	.vdisplay = 1600,
-	.vsync_start = 1600 + 3,
-	.vsync_end = 1600 + 3 + 10,
-	.vtotal = 1600 + 3 + 10 + 33,
-	.vrefresh = 60,
-	.flags = DRM_MODE_FLAG_NVSYNC | DRM_MODE_FLAG_NHSYNC,
+static const struct display_timing sharp_lq123p1jx31_timing = {
+	.pixelclock = { 252750000, 252750000, 266604720 },
+	.hactive = { 2400, 2400, 2400 },
+	.hfront_porch = { 48, 48, 48 },
+	.hback_porch = { 80, 80, 84 },
+	.hsync_len = { 32, 32, 32 },
+	.vactive = { 1600, 1600, 1600 },
+	.vfront_porch = { 3, 3, 3 },
+	.vback_porch = { 33, 33, 120 },
+	.vsync_len = { 10, 10, 10 },
+	.flags = DISPLAY_FLAGS_VSYNC_LOW | DISPLAY_FLAGS_HSYNC_LOW,
 };
 
 static const struct panel_desc sharp_lq123p1jx31 = {
-	.modes = &sharp_lq123p1jx31_mode,
-	.num_modes = 1,
+	.timings = &sharp_lq123p1jx31_timing,
+	.num_timings = 1,
 	.bpc = 8,
 	.size = {
 		.width = 259,
-- 
2.16.0.rc1.238.g530d649a79-goog

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[PATCH v2 3/5] drm/panel: simple: Add ability to override typical timing

[Sean Paul]

This patch adds the ability to override the typical display timing for a
given panel. This is useful for devices which have timing constraints
that do not apply across the entire display driver (eg: to avoid
crosstalk between panel and digitizer on certain laptops). The rules are
as follows:

- panel must not specify fixed mode (since the override mode will
  either be the same as the fixed mode, or we'll be unable to
  check the bounds of the overried)
- panel must specify at least one display_timing range which will be
  used to ensure the override mode fits within its bounds

Changes in v2:
 - Parse the full display-timings node (using the native-mode) (Rob)

Cc: Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Cc: Eric Anholt <eric-WhKQ6XTQaPysTnJN9+BGXg@public.gmane.org>
Cc: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>
Cc: Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
Cc: Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Stéphane Marchesin <marcheu-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Cc: Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
Signed-off-by: Sean Paul <seanpaul-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---
 drivers/gpu/drm/panel/panel-simple.c | 77 +++++++++++++++++++++++++++++++++++-
 1 file changed, 76 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index 5591984a392b..c1635b35f97e 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -34,6 +34,7 @@
 #include <drm/drm_panel.h>
 
 #include <video/display_timing.h>
+#include <video/of_display_timing.h>
 #include <video/videomode.h>
 
 struct panel_desc {
@@ -87,6 +88,8 @@ struct panel_simple {
 	struct i2c_adapter *ddc;
 
 	struct gpio_desc *enable_gpio;
+
+	struct drm_display_mode override_mode;
 };
 
 static inline struct panel_simple *to_panel_simple(struct drm_panel *panel)
@@ -99,11 +102,22 @@ static int panel_simple_get_fixed_modes(struct panel_simple *panel)
 	struct drm_connector *connector = panel->base.connector;
 	struct drm_device *drm = panel->base.drm;
 	struct drm_display_mode *mode;
+	bool has_override = panel->override_mode.type;
 	unsigned int i, num = 0;
 
 	if (!panel->desc)
 		return 0;
 
+	if (has_override) {
+		mode = drm_mode_duplicate(drm, &panel->override_mode);
+		if (mode) {
+			drm_mode_probed_add(connector, mode);
+			num++;
+		} else {
+			dev_err(drm->dev, "failed to add override mode\n");
+		}
+	}
+
 	for (i = 0; i < panel->desc->num_timings; i++) {
 		const struct display_timing *dt = &panel->desc->timings[i];
 		struct videomode vm;
@@ -120,7 +134,7 @@ static int panel_simple_get_fixed_modes(struct panel_simple *panel)
 
 		mode->type |= DRM_MODE_TYPE_DRIVER;
 
-		if (panel->desc->num_timings == 1)
+		if (panel->desc->num_timings == 1 && !has_override)
 			mode->type |= DRM_MODE_TYPE_PREFERRED;
 
 		drm_mode_probed_add(connector, mode);
@@ -291,10 +305,58 @@ static const struct drm_panel_funcs panel_simple_funcs = {
 	.get_timings = panel_simple_get_timings,
 };
 
+#define PANEL_SIMPLE_BOUNDS_CHECK(to_check, bounds, field) \
+	(to_check->field.typ >= bounds->field.min && \
+	 to_check->field.typ <= bounds->field.max)
+static void panel_simple_add_override_mode(struct device *dev,
+					   struct panel_simple *panel,
+					   const struct display_timing *ot)
+{
+	const struct panel_desc *desc = panel->desc;
+	struct videomode vm;
+	int i;
+
+	if (desc->num_modes) {
+		dev_err(dev, "Reject override mode: panel has a fixed mode\n");
+		return;
+	}
+	if (!desc->num_timings) {
+		dev_err(dev, "Reject override mode: no timings specified\n");
+		return;
+	}
+
+	for (i = 0; i < panel->desc->num_timings; i++) {
+		const struct display_timing *dt = &panel->desc->timings[i];
+
+		if (!PANEL_SIMPLE_BOUNDS_CHECK(ot, dt, hactive) ||
+		    !PANEL_SIMPLE_BOUNDS_CHECK(ot, dt, hfront_porch) ||
+		    !PANEL_SIMPLE_BOUNDS_CHECK(ot, dt, hback_porch) ||
+		    !PANEL_SIMPLE_BOUNDS_CHECK(ot, dt, hsync_len) ||
+		    !PANEL_SIMPLE_BOUNDS_CHECK(ot, dt, vactive) ||
+		    !PANEL_SIMPLE_BOUNDS_CHECK(ot, dt, vfront_porch) ||
+		    !PANEL_SIMPLE_BOUNDS_CHECK(ot, dt, vback_porch) ||
+		    !PANEL_SIMPLE_BOUNDS_CHECK(ot, dt, vsync_len))
+			continue;
+
+		if (ot->flags != dt->flags)
+			continue;
+
+		videomode_from_timing(ot, &vm);
+		drm_display_mode_from_videomode(&vm, &panel->override_mode);
+		panel->override_mode.type |= DRM_MODE_TYPE_DRIVER |
+					     DRM_MODE_TYPE_PREFERRED;
+		return;
+	}
+
+	dev_err(dev, "Reject override mode: No display_timing found\n");
+	return;
+}
+
 static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
 {
 	struct device_node *backlight, *ddc;
 	struct panel_simple *panel;
+	struct display_timings *dt;
 	int err;
 
 	panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
@@ -338,6 +400,19 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
 		}
 	}
 
+	dt = of_get_display_timings(dev->of_node);
+	if (dt && dt->num_timings) {
+		/*
+		 * Only attempt adding the native mode from the provided display
+		 * timings. It doesn't really make sense to try multiple modes
+		 * since the override is meant to be tailored to the
+		 * device/panel.
+		 */
+		panel_simple_add_override_mode(dev, panel,
+					       dt->timings[dt->native_mode]);
+		display_timings_release(dt);
+	}
+
 	drm_panel_init(&panel->base);
 	panel->base.dev = dev;
 	panel->base.funcs = &panel_simple_funcs;
-- 
2.16.0.rc1.238.g530d649a79-goog

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[PATCH v2 5/5] arm64: dts: rockchip: Specify override mode for kevin panel

[Sean Paul]

This patch adds an override mode for kevin devices. The mode increases
both back porches to allow a pixel clock of 26666kHz as opposed to the
'typical' value of 252750kHz. This is needed to avoid interference with
the touch digitizer on these laptops.

Changes in v2:
 - Wrap the timing in display-timings node to match binding (Rob/Thierry)

Cc: Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Cc: Eric Anholt <eric-WhKQ6XTQaPysTnJN9+BGXg@public.gmane.org>
Cc: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>
Cc: Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
Cc: Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Stéphane Marchesin <marcheu-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Cc: Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
Cc: linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Signed-off-by: Sean Paul <seanpaul-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---
 arch/arm64/boot/dts/rockchip/rk3399-gru-kevin.dts | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/arm64/boot/dts/rockchip/rk3399-gru-kevin.dts b/arch/arm64/boot/dts/rockchip/rk3399-gru-kevin.dts
index 191a6bcb1704..800eabd39076 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-gru-kevin.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3399-gru-kevin.dts
@@ -98,6 +98,22 @@
 		backlight = <&backlight>;
 		power-supply = <&pp3300_disp>;
 
+		display-timings {
+			timing0: override {
+				clock-frequency = <266604720>;
+				hactive = <2400>;
+				hfront-porch = <48>;
+				hback-porch = <84>;
+				hsync-len = <32>;
+				hsync-active = <0>;
+				vactive = <1600>;
+				vfront-porch = <3>;
+				vback-porch = <120>;
+				vsync-len = <10>;
+				vsync-active = <0>;
+			};
+		};
+
 		ports {
 			panel_in_edp: endpoint {
 				remote-endpoint = <&edp_out_panel>;
-- 
2.16.0.rc1.238.g530d649a79-goog

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