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* [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support
@ 2019-05-11 21:06 Laurent Pinchart
  2019-05-11 21:06 ` [PATCH v2 01/10] drm: bridge: Add dual_link field to the drm_bridge_timings structure Laurent Pinchart
                   ` (11 more replies)
  0 siblings, 12 replies; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-11 21:06 UTC (permalink / raw)
  To: dri-devel
  Cc: linux-renesas-soc, Kieran Bingham, Andrzej Hajda, devicetree,
	Jacopo Mondi

Hello everybody,

This patch series implements support for LVDS dual-link mode in the
R-Car DU and R-Car LVDS encoder drivers, and well as in the thc63lvd1024
LVDS decoder driver.

LVDS dual-link is a mode of operation where two individual LVDS links
are operated together to carry even- and odd-numbered pixels separately.
This doubles the possible bandwidth of the video transmission. Both the
transmitter and the receiver need to support this mode of operation.

The R-Car D3 and E3 SoCs include two independent LVDS encoders that can
be grouped together to operate in dual-link mode. When used separately,
the LVDS encoders are connected to two different CRTCs and transmit
independent video streams. When used in dual-link mode, the first LVDS
encoder is connected to the first CRTC, and split even- and odd-numbered
pixels. It transmits half of the pixels on its LVDS output, and sends
the other half to the second LVDS encoder for transmittion over the
second LVDS link. The second LVDS encoder thus operates under control of
the first one, and isn't connected directly to a CRTC.

On the receiving side, the THC63LVD1024 LVDS-to-parallel bridge has two
LVDS inputs and two parallel outputs. It can operate in four different
modes:

- Single-in, single-out: The first LVDS input receives the video stream,
  and the bridge outputs it on the first parallel output. The second
  LVDS input and the second parallel output are not used.

- Single-in, dual-out: The first LVDS input receives the video stream,
  and the bridge splits even- and odd-numbered pixels and outputs them
  on the first and second parallel outputs. The second LVDS input is not
  used.

- Dual-in, single-out: The two LVDS inputs are used in dual-link mode,
  and the bridge combines the even- and odd-numbered pixels and outputs
  them on the first parallel output. The second parallel output is not
  used.

- Dual-in, dual-out: The two LVDS inputs are used in dual-link mode,
  and the bridge outputs the even- and odd-numbered pixels on the first
  parallel output.

The operating mode is selected by two input pins of the bridge, which
are connected to DIP switches on the development boards I use. The mode
is thus fixed from a Linux point of view.

Patch 01/10 adds a new dual_link boolen field to the drm_bridge_timings
structure to let bridges report their LVDS mode of operation. Patch
02/10 clarifies the THC63LVD1024 DT bindings to document dual-link
operation, and patch 03/10 implements dual-link support in the
thc64lvd1024 bridge driver by setting the drm_bridge_timings dual_link
field according to the mode selected through DT.

Patch 04/10 extends the R-Car LVDS DT bindings to specify the companion
LVDS encoder for dual-link operation. Patches 05/10 then performs a
small cleanup in the LVDS encoder driver. Patch 06/10 implements
dual-link support in the LVDS encoder driver, which involves retrieving
the operation mode from the LVDS receiver, locating the companion LVDS
encoder, and configuring both encoders when dual-link operation is
desired. The API towards the DU driver is also extended to report the
mode of operation.

Patch 07/10 implements dual-link mode support in the DU driver. There is
no specific configuration to be performed there, as dual-link is fully
implemented in the LVDS encoder driver, but the DU driver has to skip
creation of the DRM encoder and connector related to the second LVDS
encoder when dual-link is used, as the second LVDS encoder operates as a
slave of the first one, transparently from a CRTC (and thus userspace)
perspective.

Patch 08/10 specifies the companion LVDS encoder in the D3 and E3 DT
bindings. This by itself doesn't enable dual-link mode, the LVDS0
encoder is still connected to the HDMI output through LVDS receiver, and
the LVDS1 encoder is not used. Patches 09/10 and 10/10, not intended to
be merged, enable dual-link operation for the D3 and E3 boards for
testing and require flipping DIP switches on the boards.

The patches are based on top of my drm/du/next branch, and are available
for convenience at

        git://linuxtv.org/pinchartl/media.git drm/du/lvds/dual-link

They have been tested successfully on the D3 Draak board. I expect them
to work on E3 as well, but I don't have access to an Ebisu board to test
this.

Laurent Pinchart (10):
  drm: bridge: Add dual_link field to the drm_bridge_timings structure
  dt-bindings: display: bridge: thc63lvd1024: Document dual-link
    operation
  drm: bridge: thc63: Report input bus mode through bridge timings
  dt-bindings: display: renesas: lvds: Add renesas,companion property
  drm: rcar-du: lvds: Remove LVDS double-enable checks
  drm: rcar-du: lvds: Add support for dual-link mode
  drm: rcar-du: Skip LVDS1 output on Gen3 when using dual-link LVDS mode
  arm64: dts: renesas: r8a7799[05]: Point LVDS0 to its companion LVDS1
  [HACK] arm64: dts: renesas: draak: Enable LVDS dual-link operation
  [HACK] arm64: dts: renesas: ebisu: Enable LVDS dual-link operation

 .../bindings/display/bridge/renesas,lvds.txt  |   6 +
 .../display/bridge/thine,thc63lvd1024.txt     |   6 +
 .../arm64/boot/dts/renesas/r8a77990-ebisu.dts |  21 ++-
 arch/arm64/boot/dts/renesas/r8a77990.dtsi     |   2 +
 .../arm64/boot/dts/renesas/r8a77995-draak.dts |  21 ++-
 arch/arm64/boot/dts/renesas/r8a77995.dtsi     |   2 +
 drivers/gpu/drm/bridge/thc63lvd1024.c         |  54 ++++++--
 drivers/gpu/drm/rcar-du/rcar_du_encoder.c     |  12 ++
 drivers/gpu/drm/rcar-du/rcar_du_kms.c         |   2 +-
 drivers/gpu/drm/rcar-du/rcar_lvds.c           | 123 +++++++++++++-----
 drivers/gpu/drm/rcar-du/rcar_lvds.h           |   5 +
 include/drm/drm_bridge.h                      |   8 ++
 12 files changed, 214 insertions(+), 48 deletions(-)

-- 
Regards,

Laurent Pinchart


^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v2 01/10] drm: bridge: Add dual_link field to the drm_bridge_timings structure
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
@ 2019-05-11 21:06 ` Laurent Pinchart
  2019-05-11 21:06 ` [PATCH v2 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation Laurent Pinchart
                   ` (10 subsequent siblings)
  11 siblings, 0 replies; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-11 21:06 UTC (permalink / raw)
  To: dri-devel
  Cc: linux-renesas-soc, Kieran Bingham, Andrzej Hajda, Kieran Bingham

Extend the drm_bridge_timings structure with a new dual_link field to
indicate that the bridge's input bus carries data on two separate
physical links. The first use case is LVDS dual-link mode where even-
and odd-numbered pixels are transferred on separate LVDS links.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
---
 include/drm/drm_bridge.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index d4428913a4e1..aea1fcfd92a7 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -265,6 +265,14 @@ struct drm_bridge_timings {
 	 * input signal after the clock edge.
 	 */
 	u32 hold_time_ps;
+	/**
+	 * @dual_link:
+	 *
+	 * True if the bus operates in dual-link mode. The exact meaning is
+	 * dependent on the bus type. For LVDS buses, this indicates that even-
+	 * and odd-numbered pixels are received on separate links.
+	 */
+	bool dual_link;
 };
 
 /**
-- 
Regards,

Laurent Pinchart


^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v2 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
  2019-05-11 21:06 ` [PATCH v2 01/10] drm: bridge: Add dual_link field to the drm_bridge_timings structure Laurent Pinchart
@ 2019-05-11 21:06 ` Laurent Pinchart
  2019-05-12  8:58   ` Geert Uytterhoeven
  2019-05-14 20:17   ` Rob Herring
  2019-05-11 21:06 ` [PATCH v2 03/10] drm: bridge: thc63: Report input bus mode through bridge timings Laurent Pinchart
                   ` (9 subsequent siblings)
  11 siblings, 2 replies; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-11 21:06 UTC (permalink / raw)
  To: dri-devel; +Cc: linux-renesas-soc, Kieran Bingham, devicetree, Jacopo Mondi

The THC63LVD1024 LVDS decoder can operate in two modes, single-link or
dual-link. In dual-link mode both input ports are used to carry even-
and odd-numbered pixels separately. Document this in the DT bindings,
along with the related rules governing port and usage.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
---
 .../bindings/display/bridge/thine,thc63lvd1024.txt          | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt b/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
index 37f0c04d5a28..d17d1e5820d7 100644
--- a/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
+++ b/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
@@ -28,6 +28,12 @@ Optional video port nodes:
 - port@1: Second LVDS input port
 - port@3: Second digital CMOS/TTL parallel output
 
+The device can operate in single-link mode or dual-link mode. In single-link
+mode, all pixels are received on port@0, and port@1 shall not contain any
+endpoint. In dual-link mode, even-numbered pixels are received on port@0 and
+odd-numbered pixels on port@1, and both port@0 and port@1 shall contain
+endpoints.
+
 Example:
 --------
 
-- 
Regards,

Laurent Pinchart


^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v2 03/10] drm: bridge: thc63: Report input bus mode through bridge timings
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
  2019-05-11 21:06 ` [PATCH v2 01/10] drm: bridge: Add dual_link field to the drm_bridge_timings structure Laurent Pinchart
  2019-05-11 21:06 ` [PATCH v2 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation Laurent Pinchart
@ 2019-05-11 21:06 ` Laurent Pinchart
  2019-05-28  9:05   ` Jacopo Mondi
  2019-05-11 21:06 ` [PATCH v2 04/10] dt-bindings: display: renesas: lvds: Add renesas,companion property Laurent Pinchart
                   ` (8 subsequent siblings)
  11 siblings, 1 reply; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-11 21:06 UTC (permalink / raw)
  To: dri-devel; +Cc: linux-renesas-soc, Kieran Bingham, Andrzej Hajda, Jacopo Mondi

Set a drm_bridge_timings in the drm_bridge, and use it to report the
input bus mode (single-link or dual-link). The other fields of the
timings structure are kept to 0 as they do not apply to LVDS buses.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
Changes since v1:

- Ignore disabled remote device
---
 drivers/gpu/drm/bridge/thc63lvd1024.c | 54 +++++++++++++++++++++------
 1 file changed, 43 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/bridge/thc63lvd1024.c b/drivers/gpu/drm/bridge/thc63lvd1024.c
index b083a740565c..709dd28b43d6 100644
--- a/drivers/gpu/drm/bridge/thc63lvd1024.c
+++ b/drivers/gpu/drm/bridge/thc63lvd1024.c
@@ -31,6 +31,8 @@ struct thc63_dev {
 
 	struct drm_bridge bridge;
 	struct drm_bridge *next;
+
+	struct drm_bridge_timings timings;
 };
 
 static inline struct thc63_dev *to_thc63(struct drm_bridge *bridge)
@@ -48,15 +50,28 @@ static int thc63_attach(struct drm_bridge *bridge)
 static enum drm_mode_status thc63_mode_valid(struct drm_bridge *bridge,
 					const struct drm_display_mode *mode)
 {
+	struct thc63_dev *thc63 = to_thc63(bridge);
+	unsigned int min_freq;
+	unsigned int max_freq;
+
 	/*
-	 * The THC63LVD1024 clock frequency range is 8 to 135 MHz in single-in
-	 * mode. Note that the limits are different in dual-in, single-out mode,
-	 * and will need to be adjusted accordingly.
+	 * The THC63LVD1024 pixel rate range is 8 to 135 MHz in all modes but
+	 * dual-in, single-out where it is 40 to 150 MHz. As dual-in, dual-out
+	 * isn't supported by the driver yet, simply derive the limits from the
+	 * input mode.
 	 */
-	if (mode->clock < 8000)
+	if (thc63->timings.dual_link) {
+		min_freq = 40000;
+		max_freq = 150000;
+	} else {
+		min_freq = 8000;
+		max_freq = 135000;
+	}
+
+	if (mode->clock < min_freq)
 		return MODE_CLOCK_LOW;
 
-	if (mode->clock > 135000)
+	if (mode->clock > max_freq)
 		return MODE_CLOCK_HIGH;
 
 	return MODE_OK;
@@ -101,19 +116,19 @@ static const struct drm_bridge_funcs thc63_bridge_func = {
 
 static int thc63_parse_dt(struct thc63_dev *thc63)
 {
-	struct device_node *thc63_out;
+	struct device_node *endpoint;
 	struct device_node *remote;
 
-	thc63_out = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
-						  THC63_RGB_OUT0, -1);
-	if (!thc63_out) {
+	endpoint = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
+						 THC63_RGB_OUT0, -1);
+	if (!endpoint) {
 		dev_err(thc63->dev, "Missing endpoint in port@%u\n",
 			THC63_RGB_OUT0);
 		return -ENODEV;
 	}
 
-	remote = of_graph_get_remote_port_parent(thc63_out);
-	of_node_put(thc63_out);
+	remote = of_graph_get_remote_port_parent(endpoint);
+	of_node_put(endpoint);
 	if (!remote) {
 		dev_err(thc63->dev, "Endpoint in port@%u unconnected\n",
 			THC63_RGB_OUT0);
@@ -132,6 +147,22 @@ static int thc63_parse_dt(struct thc63_dev *thc63)
 	if (!thc63->next)
 		return -EPROBE_DEFER;
 
+	endpoint = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
+						 THC63_LVDS_IN1, -1);
+	if (endpoint) {
+		remote = of_graph_get_remote_port_parent(endpoint);
+		of_node_put(endpoint);
+
+		if (remote) {
+			if (of_device_is_available(remote))
+				thc63->timings.dual_link = true;
+			of_node_put(remote);
+		}
+	}
+
+	dev_dbg(thc63->dev, "operating in %s-link mode\n",
+		thc63->timings.dual_link ? "dual" : "single");
+
 	return 0;
 }
 
@@ -188,6 +219,7 @@ static int thc63_probe(struct platform_device *pdev)
 	thc63->bridge.driver_private = thc63;
 	thc63->bridge.of_node = pdev->dev.of_node;
 	thc63->bridge.funcs = &thc63_bridge_func;
+	thc63->bridge.timings = &thc63->timings;
 
 	drm_bridge_add(&thc63->bridge);
 
-- 
Regards,

Laurent Pinchart


^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v2 04/10] dt-bindings: display: renesas: lvds: Add renesas,companion property
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
                   ` (2 preceding siblings ...)
  2019-05-11 21:06 ` [PATCH v2 03/10] drm: bridge: thc63: Report input bus mode through bridge timings Laurent Pinchart
@ 2019-05-11 21:06 ` Laurent Pinchart
  2019-05-28  9:28   ` Jacopo Mondi
  2019-05-11 21:06 ` [PATCH v2 05/10] drm: rcar-du: lvds: Remove LVDS double-enable checks Laurent Pinchart
                   ` (7 subsequent siblings)
  11 siblings, 1 reply; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-11 21:06 UTC (permalink / raw)
  To: dri-devel; +Cc: linux-renesas-soc, Kieran Bingham, devicetree

Add a new optional renesas,companion property to point to the companion
LVDS encoder. This is used to support dual-link operation where the main
LVDS encoder splits even-numbered and odd-numbered pixels between the
two LVDS encoders.

The new property doesn't control the mode of operation, it only
describes the relationship between the master and companion LVDS
encoders.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
Changes since v1:

- Fixed typo
---
 .../devicetree/bindings/display/bridge/renesas,lvds.txt     | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt b/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt
index 900a884ad9f5..f2cc01d54cbd 100644
--- a/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt
+++ b/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt
@@ -45,6 +45,12 @@ OF graph bindings specified in Documentation/devicetree/bindings/graph.txt.
 
 Each port shall have a single endpoint.
 
+Optional properties:
+
+- renesas,companion : phandle to the companion LVDS encoder. This property is
+  valid for the first LVDS encoder on D3 and E3 SoCs only, and points to the
+  second encoder to be used as a companion in dual-link mode.
+
 
 Example:
 
-- 
Regards,

Laurent Pinchart


^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v2 05/10] drm: rcar-du: lvds: Remove LVDS double-enable checks
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
                   ` (3 preceding siblings ...)
  2019-05-11 21:06 ` [PATCH v2 04/10] dt-bindings: display: renesas: lvds: Add renesas,companion property Laurent Pinchart
@ 2019-05-11 21:06 ` Laurent Pinchart
  2019-05-28  9:40   ` Jacopo Mondi
  2019-05-11 21:06 ` [PATCH v2 06/10] drm: rcar-du: lvds: Add support for dual-link mode Laurent Pinchart
                   ` (6 subsequent siblings)
  11 siblings, 1 reply; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-11 21:06 UTC (permalink / raw)
  To: dri-devel; +Cc: linux-renesas-soc, Kieran Bingham

The DRM core and DU driver guarantee that the LVDS bridge will not be
double-enabled or double-disabled. Remove the corresponding unnecessary
checks.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 drivers/gpu/drm/rcar-du/rcar_lvds.c | 19 -------------------
 1 file changed, 19 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
index 620b51aab291..a331f0c32187 100644
--- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
@@ -63,7 +63,6 @@ struct rcar_lvds {
 		struct clk *extal;		/* External clock */
 		struct clk *dotclkin[2];	/* External DU clocks */
 	} clocks;
-	bool enabled;
 
 	struct drm_display_mode display_mode;
 	enum rcar_lvds_mode mode;
@@ -368,15 +367,12 @@ int rcar_lvds_clk_enable(struct drm_bridge *bridge, unsigned long freq)
 
 	dev_dbg(lvds->dev, "enabling LVDS PLL, freq=%luHz\n", freq);
 
-	WARN_ON(lvds->enabled);
-
 	ret = clk_prepare_enable(lvds->clocks.mod);
 	if (ret < 0)
 		return ret;
 
 	__rcar_lvds_pll_setup_d3_e3(lvds, freq, true);
 
-	lvds->enabled = true;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(rcar_lvds_clk_enable);
@@ -390,13 +386,9 @@ void rcar_lvds_clk_disable(struct drm_bridge *bridge)
 
 	dev_dbg(lvds->dev, "disabling LVDS PLL\n");
 
-	WARN_ON(!lvds->enabled);
-
 	rcar_lvds_write(lvds, LVDPLLCR, 0);
 
 	clk_disable_unprepare(lvds->clocks.mod);
-
-	lvds->enabled = false;
 }
 EXPORT_SYMBOL_GPL(rcar_lvds_clk_disable);
 
@@ -417,8 +409,6 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
 	u32 lvdcr0;
 	int ret;
 
-	WARN_ON(lvds->enabled);
-
 	ret = clk_prepare_enable(lvds->clocks.mod);
 	if (ret < 0)
 		return;
@@ -507,16 +497,12 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
 		drm_panel_prepare(lvds->panel);
 		drm_panel_enable(lvds->panel);
 	}
-
-	lvds->enabled = true;
 }
 
 static void rcar_lvds_disable(struct drm_bridge *bridge)
 {
 	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
 
-	WARN_ON(!lvds->enabled);
-
 	if (lvds->panel) {
 		drm_panel_disable(lvds->panel);
 		drm_panel_unprepare(lvds->panel);
@@ -527,8 +513,6 @@ static void rcar_lvds_disable(struct drm_bridge *bridge)
 	rcar_lvds_write(lvds, LVDPLLCR, 0);
 
 	clk_disable_unprepare(lvds->clocks.mod);
-
-	lvds->enabled = false;
 }
 
 static bool rcar_lvds_mode_fixup(struct drm_bridge *bridge,
@@ -592,8 +576,6 @@ static void rcar_lvds_mode_set(struct drm_bridge *bridge,
 {
 	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
 
-	WARN_ON(lvds->enabled);
-
 	lvds->display_mode = *adjusted_mode;
 
 	rcar_lvds_get_lvds_mode(lvds);
@@ -793,7 +775,6 @@ static int rcar_lvds_probe(struct platform_device *pdev)
 
 	lvds->dev = &pdev->dev;
 	lvds->info = of_device_get_match_data(&pdev->dev);
-	lvds->enabled = false;
 
 	ret = rcar_lvds_parse_dt(lvds);
 	if (ret < 0)
-- 
Regards,

Laurent Pinchart


^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v2 06/10] drm: rcar-du: lvds: Add support for dual-link mode
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
                   ` (4 preceding siblings ...)
  2019-05-11 21:06 ` [PATCH v2 05/10] drm: rcar-du: lvds: Remove LVDS double-enable checks Laurent Pinchart
@ 2019-05-11 21:06 ` Laurent Pinchart
  2019-05-28  9:35   ` Jacopo Mondi
  2019-05-11 21:06 ` [PATCH v2 07/10] drm: rcar-du: Skip LVDS1 output on Gen3 when using dual-link LVDS mode Laurent Pinchart
                   ` (5 subsequent siblings)
  11 siblings, 1 reply; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-11 21:06 UTC (permalink / raw)
  To: dri-devel; +Cc: linux-renesas-soc, Kieran Bingham, Jacopo Mondi

In dual-link mode the LVDS0 encoder transmits even-numbered pixels, and
sends odd-numbered pixels to the LVDS1 encoder for transmission on a
separate link.

To implement support for this mode of operation, determine if the LVDS
connection operates in dual-link mode by querying the next device in the
pipeline, locate the companion encoder, and control it directly through
its bridge operations.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
---
 drivers/gpu/drm/rcar-du/rcar_lvds.c | 104 ++++++++++++++++++++++++----
 drivers/gpu/drm/rcar-du/rcar_lvds.h |   5 ++
 2 files changed, 96 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
index a331f0c32187..f7e4710fe33f 100644
--- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
@@ -66,6 +66,9 @@ struct rcar_lvds {
 
 	struct drm_display_mode display_mode;
 	enum rcar_lvds_mode mode;
+
+	struct drm_bridge *companion;
+	bool dual_link;
 };
 
 #define bridge_to_rcar_lvds(bridge) \
@@ -400,11 +403,6 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
 {
 	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
 	const struct drm_display_mode *mode = &lvds->display_mode;
-	/*
-	 * FIXME: We should really retrieve the CRTC through the state, but how
-	 * do we get a state pointer?
-	 */
-	struct drm_crtc *crtc = lvds->bridge.encoder->crtc;
 	u32 lvdhcr;
 	u32 lvdcr0;
 	int ret;
@@ -413,6 +411,10 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
 	if (ret < 0)
 		return;
 
+	/* Enable the companion LVDS encoder in dual-link mode. */
+	if (lvds->dual_link && lvds->companion)
+		lvds->companion->funcs->enable(lvds->companion);
+
 	/*
 	 * Hardcode the channels and control signals routing for now.
 	 *
@@ -435,17 +437,33 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
 	rcar_lvds_write(lvds, LVDCHCR, lvdhcr);
 
 	if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK) {
-		/* Disable dual-link mode. */
-		rcar_lvds_write(lvds, LVDSTRIPE, 0);
+		/*
+		 * Configure vertical stripe based on the mode of operation of
+		 * the connected device.
+		 */
+		rcar_lvds_write(lvds, LVDSTRIPE,
+				lvds->dual_link ? LVDSTRIPE_ST_ON : 0);
 	}
 
-	/* PLL clock configuration. */
-	lvds->info->pll_setup(lvds, mode->clock * 1000);
+	/*
+	 * PLL clock configuration on all instances but the companion in
+	 * dual-link mode.
+	 */
+	if (!lvds->dual_link || lvds->companion)
+		lvds->info->pll_setup(lvds, mode->clock * 1000);
 
 	/* Set the LVDS mode and select the input. */
 	lvdcr0 = lvds->mode << LVDCR0_LVMD_SHIFT;
-	if (drm_crtc_index(crtc) == 2)
-		lvdcr0 |= LVDCR0_DUSEL;
+
+	if (lvds->bridge.encoder) {
+		/*
+		 * FIXME: We should really retrieve the CRTC through the state,
+		 * but how do we get a state pointer?
+		 */
+		if (drm_crtc_index(lvds->bridge.encoder->crtc) == 2)
+			lvdcr0 |= LVDCR0_DUSEL;
+	}
+
 	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
 
 	/* Turn all the channels on. */
@@ -512,6 +530,10 @@ static void rcar_lvds_disable(struct drm_bridge *bridge)
 	rcar_lvds_write(lvds, LVDCR1, 0);
 	rcar_lvds_write(lvds, LVDPLLCR, 0);
 
+	/* Disable the companion LVDS encoder in dual-link mode. */
+	if (lvds->dual_link && lvds->companion)
+		lvds->companion->funcs->disable(lvds->companion);
+
 	clk_disable_unprepare(lvds->clocks.mod);
 }
 
@@ -628,10 +650,54 @@ static const struct drm_bridge_funcs rcar_lvds_bridge_ops = {
 	.mode_set = rcar_lvds_mode_set,
 };
 
+bool rcar_lvds_dual_link(struct drm_bridge *bridge)
+{
+	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
+
+	return lvds->dual_link;
+}
+EXPORT_SYMBOL_GPL(rcar_lvds_dual_link);
+
 /* -----------------------------------------------------------------------------
  * Probe & Remove
  */
 
+static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
+{
+	const struct of_device_id *match;
+	struct device_node *companion;
+	struct device *dev = lvds->dev;
+	int ret = 0;
+
+	/* Locate the companion LVDS encoder for dual-link operation, if any. */
+	companion = of_parse_phandle(dev->of_node, "renesas,companion", 0);
+	if (!companion)
+		return -ENODEV;
+
+	/*
+	 * Sanity check: the companion encoder must have the same compatible
+	 * string.
+	 */
+	match = of_match_device(dev->driver->of_match_table, dev);
+	if (!of_device_is_compatible(companion, match->compatible)) {
+		ret = -ENODEV;
+		goto done;
+	}
+
+	lvds->companion = of_drm_find_bridge(companion);
+	if (!lvds->companion) {
+		ret = -EPROBE_DEFER;
+		goto done;
+	}
+
+	dev_dbg(dev, "Found companion encoder %pOF\n", companion);
+
+done:
+	of_node_put(companion);
+
+	return ret;
+}
+
 static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
 {
 	struct device_node *local_output = NULL;
@@ -682,14 +748,26 @@ static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
 
 	if (is_bridge) {
 		lvds->next_bridge = of_drm_find_bridge(remote);
-		if (!lvds->next_bridge)
+		if (!lvds->next_bridge) {
 			ret = -EPROBE_DEFER;
+			goto done;
+		}
+
+		if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK)
+			lvds->dual_link = lvds->next_bridge->timings
+					? lvds->next_bridge->timings->dual_link
+					: false;
 	} else {
 		lvds->panel = of_drm_find_panel(remote);
-		if (IS_ERR(lvds->panel))
+		if (IS_ERR(lvds->panel)) {
 			ret = PTR_ERR(lvds->panel);
+			goto done;
+		}
 	}
 
+	if (lvds->dual_link)
+		ret = rcar_lvds_parse_dt_companion(lvds);
+
 done:
 	of_node_put(local_output);
 	of_node_put(remote_input);
diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.h b/drivers/gpu/drm/rcar-du/rcar_lvds.h
index a709cae1bc32..222ec0e60785 100644
--- a/drivers/gpu/drm/rcar-du/rcar_lvds.h
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.h
@@ -15,6 +15,7 @@ struct drm_bridge;
 #if IS_ENABLED(CONFIG_DRM_RCAR_LVDS)
 int rcar_lvds_clk_enable(struct drm_bridge *bridge, unsigned long freq);
 void rcar_lvds_clk_disable(struct drm_bridge *bridge);
+bool rcar_lvds_dual_link(struct drm_bridge *bridge);
 #else
 static inline int rcar_lvds_clk_enable(struct drm_bridge *bridge,
 				       unsigned long freq)
@@ -22,6 +23,10 @@ static inline int rcar_lvds_clk_enable(struct drm_bridge *bridge,
 	return -ENOSYS;
 }
 static inline void rcar_lvds_clk_disable(struct drm_bridge *bridge) { }
+static inline bool rcar_lvds_dual_link(struct drm_bridge *bridge)
+{
+	return false;
+}
 #endif /* CONFIG_DRM_RCAR_LVDS */
 
 #endif /* __RCAR_LVDS_H__ */
-- 
Regards,

Laurent Pinchart


^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v2 07/10] drm: rcar-du: Skip LVDS1 output on Gen3 when using dual-link LVDS mode
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
                   ` (5 preceding siblings ...)
  2019-05-11 21:06 ` [PATCH v2 06/10] drm: rcar-du: lvds: Add support for dual-link mode Laurent Pinchart
@ 2019-05-11 21:06 ` Laurent Pinchart
  2019-05-28  9:38   ` Jacopo Mondi
  2019-05-11 21:07 ` [PATCH v2 08/10] arm64: dts: renesas: r8a7799[05]: Point LVDS0 to its companion LVDS1 Laurent Pinchart
                   ` (4 subsequent siblings)
  11 siblings, 1 reply; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-11 21:06 UTC (permalink / raw)
  To: dri-devel; +Cc: linux-renesas-soc, Kieran Bingham

In dual-link LVDS mode, the LVDS1 encoder is used as a companion for
LVDS0, and both encoders transmit data from DU0. The LVDS1 output of DU1
can't be used in that case, don't create an encoder and connector for
it.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 drivers/gpu/drm/rcar-du/rcar_du_encoder.c | 12 ++++++++++++
 drivers/gpu/drm/rcar-du/rcar_du_kms.c     |  2 +-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
index 6c91753af7bc..fe046d194944 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
@@ -16,6 +16,7 @@
 #include "rcar_du_drv.h"
 #include "rcar_du_encoder.h"
 #include "rcar_du_kms.h"
+#include "rcar_lvds.h"
 
 /* -----------------------------------------------------------------------------
  * Encoder
@@ -97,6 +98,17 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
 		}
 	}
 
+	/*
+	 * On Gen3 skip the LVDS1 output if the LVDS1 encoder is used as a
+	 * companion for LVDS0 in dual-link mode.
+	 */
+	if (rcdu->info->gen >= 3 && output == RCAR_DU_OUTPUT_LVDS1) {
+		if (bridge && rcar_lvds_dual_link(bridge)) {
+			ret = -ENOLINK;
+			goto done;
+		}
+	}
+
 	ret = drm_encoder_init(rcdu->ddev, encoder, &encoder_funcs,
 			       DRM_MODE_ENCODER_NONE, NULL);
 	if (ret < 0)
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
index f8f7fff34dff..95c81e59e2f1 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
@@ -378,7 +378,7 @@ static int rcar_du_encoders_init_one(struct rcar_du_device *rcdu,
 	}
 
 	ret = rcar_du_encoder_init(rcdu, output, entity);
-	if (ret && ret != -EPROBE_DEFER)
+	if (ret && ret != -EPROBE_DEFER && ret != -ENOLINK)
 		dev_warn(rcdu->dev,
 			 "failed to initialize encoder %pOF on output %u (%d), skipping\n",
 			 entity, output, ret);
-- 
Regards,

Laurent Pinchart


^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v2 08/10] arm64: dts: renesas: r8a7799[05]: Point LVDS0 to its companion LVDS1
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
                   ` (6 preceding siblings ...)
  2019-05-11 21:06 ` [PATCH v2 07/10] drm: rcar-du: Skip LVDS1 output on Gen3 when using dual-link LVDS mode Laurent Pinchart
@ 2019-05-11 21:07 ` Laurent Pinchart
  2019-05-28  9:39   ` Jacopo Mondi
  2019-05-11 21:07 ` [PATCH v2 09/10] [HACK] arm64: dts: renesas: draak: Enable LVDS dual-link operation Laurent Pinchart
                   ` (3 subsequent siblings)
  11 siblings, 1 reply; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-11 21:07 UTC (permalink / raw)
  To: dri-devel; +Cc: linux-renesas-soc, Kieran Bingham

Add the new renesas,companion property to the LVDS0 node to point to the
companion LVDS encoder LVDS1.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 arch/arm64/boot/dts/renesas/r8a77990.dtsi | 2 ++
 arch/arm64/boot/dts/renesas/r8a77995.dtsi | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r8a77990.dtsi b/arch/arm64/boot/dts/renesas/r8a77990.dtsi
index d2ad665fe2d9..b52e3fdb5fca 100644
--- a/arch/arm64/boot/dts/renesas/r8a77990.dtsi
+++ b/arch/arm64/boot/dts/renesas/r8a77990.dtsi
@@ -1731,6 +1731,8 @@
 			resets = <&cpg 727>;
 			status = "disabled";
 
+			renesas,companion = <&lvds1>;
+
 			ports {
 				#address-cells = <1>;
 				#size-cells = <0>;
diff --git a/arch/arm64/boot/dts/renesas/r8a77995.dtsi b/arch/arm64/boot/dts/renesas/r8a77995.dtsi
index 5bf3af246e14..94b5177eb152 100644
--- a/arch/arm64/boot/dts/renesas/r8a77995.dtsi
+++ b/arch/arm64/boot/dts/renesas/r8a77995.dtsi
@@ -1038,6 +1038,8 @@
 			resets = <&cpg 727>;
 			status = "disabled";
 
+			renesas,companion = <&lvds1>;
+
 			ports {
 				#address-cells = <1>;
 				#size-cells = <0>;
-- 
Regards,

Laurent Pinchart


^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v2 09/10] [HACK] arm64: dts: renesas: draak: Enable LVDS dual-link operation
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
                   ` (7 preceding siblings ...)
  2019-05-11 21:07 ` [PATCH v2 08/10] arm64: dts: renesas: r8a7799[05]: Point LVDS0 to its companion LVDS1 Laurent Pinchart
@ 2019-05-11 21:07 ` Laurent Pinchart
  2019-05-11 21:07 ` [PATCH v2 10/10] [HACK] arm64: dts: renesas: ebisu: " Laurent Pinchart
                   ` (2 subsequent siblings)
  11 siblings, 0 replies; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-11 21:07 UTC (permalink / raw)
  To: dri-devel; +Cc: linux-renesas-soc, Kieran Bingham

Enable and connect the second LVDS encoder to the second LVDS input of
the THC63LVD1024 for dual-link LVDS operation. This requires changing
the default settings of SW45 and SW47 to OFF and ON respectively.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 .../arm64/boot/dts/renesas/r8a77995-draak.dts | 21 +++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/renesas/r8a77995-draak.dts b/arch/arm64/boot/dts/renesas/r8a77995-draak.dts
index db2bed1751b8..6af0e891c1ec 100644
--- a/arch/arm64/boot/dts/renesas/r8a77995-draak.dts
+++ b/arch/arm64/boot/dts/renesas/r8a77995-draak.dts
@@ -77,11 +77,18 @@
 
 			port@0 {
 				reg = <0>;
-				thc63lvd1024_in: endpoint {
+				thc63lvd1024_in0: endpoint {
 					remote-endpoint = <&lvds0_out>;
 				};
 			};
 
+			port@1 {
+				reg = <1>;
+				thc63lvd1024_in1: endpoint {
+					remote-endpoint = <&lvds1_out>;
+				};
+			};
+
 			port@2 {
 				reg = <2>;
 				thc63lvd1024_out: endpoint {
@@ -349,17 +356,27 @@
 	ports {
 		port@1 {
 			lvds0_out: endpoint {
-				remote-endpoint = <&thc63lvd1024_in>;
+				remote-endpoint = <&thc63lvd1024_in0>;
 			};
 		};
 	};
 };
 
 &lvds1 {
+	status = "okay";
+
 	clocks = <&cpg CPG_MOD 727>,
 		 <&x12_clk>,
 		 <&extal_clk>;
 	clock-names = "fck", "dclkin.0", "extal";
+
+	ports {
+		port@1 {
+			lvds1_out: endpoint {
+				remote-endpoint = <&thc63lvd1024_in1>;
+			};
+		};
+	};
 };
 
 &ohci0 {
-- 
Regards,

Laurent Pinchart


^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v2 10/10] [HACK] arm64: dts: renesas: ebisu: Enable LVDS dual-link operation
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
                   ` (8 preceding siblings ...)
  2019-05-11 21:07 ` [PATCH v2 09/10] [HACK] arm64: dts: renesas: draak: Enable LVDS dual-link operation Laurent Pinchart
@ 2019-05-11 21:07 ` " Laurent Pinchart
  2019-05-12  8:55 ` [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Geert Uytterhoeven
  2019-05-28 10:20 ` Jacopo Mondi
  11 siblings, 0 replies; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-11 21:07 UTC (permalink / raw)
  To: dri-devel; +Cc: linux-renesas-soc, Kieran Bingham

Enable and connect the second LVDS encoder to the second LVDS input of
the THC63LVD1024 for dual-link LVDS operation. This requires changing
the default settings of SW45 and SW47 to OFF and ON respectively.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 .../arm64/boot/dts/renesas/r8a77990-ebisu.dts | 21 +++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts b/arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts
index 144c0820cf60..88bdbf4fc82c 100644
--- a/arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts
+++ b/arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts
@@ -93,11 +93,18 @@
 
 			port@0 {
 				reg = <0>;
-				thc63lvd1024_in: endpoint {
+				thc63lvd1024_in0: endpoint {
 					remote-endpoint = <&lvds0_out>;
 				};
 			};
 
+			port@1 {
+				reg = <1>;
+				thc63lvd1024_in1: endpoint {
+					remote-endpoint = <&lvds1_out>;
+				};
+			};
+
 			port@2 {
 				reg = <2>;
 				thc63lvd1024_out: endpoint {
@@ -451,17 +458,27 @@
 	ports {
 		port@1 {
 			lvds0_out: endpoint {
-				remote-endpoint = <&thc63lvd1024_in>;
+				remote-endpoint = <&thc63lvd1024_in0>;
 			};
 		};
 	};
 };
 
 &lvds1 {
+	status = "okay";
+
 	clocks = <&cpg CPG_MOD 727>,
 		 <&x13_clk>,
 		 <&extal_clk>;
 	clock-names = "fck", "dclkin.0", "extal";
+
+	ports {
+		port@1 {
+			lvds1_out: endpoint {
+				remote-endpoint = <&thc63lvd1024_in1>;
+			};
+		};
+	};
 };
 
 &ohci0 {
-- 
Regards,

Laurent Pinchart


^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
                   ` (9 preceding siblings ...)
  2019-05-11 21:07 ` [PATCH v2 10/10] [HACK] arm64: dts: renesas: ebisu: " Laurent Pinchart
@ 2019-05-12  8:55 ` Geert Uytterhoeven
  2019-05-12 10:15   ` Laurent Pinchart
  2019-05-28 10:20 ` Jacopo Mondi
  11 siblings, 1 reply; 25+ messages in thread
From: Geert Uytterhoeven @ 2019-05-12  8:55 UTC (permalink / raw)
  To: Laurent Pinchart
  Cc: DRI Development, Linux-Renesas, Kieran Bingham, Andrzej Hajda,
	open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS,
	Jacopo Mondi

Hi Laurent,

On Sat, May 11, 2019 at 11:07 PM Laurent Pinchart
<laurent.pinchart+renesas@ideasonboard.com> wrote:
> On the receiving side, the THC63LVD1024 LVDS-to-parallel bridge has two
> LVDS inputs and two parallel outputs. It can operate in four different
> modes:
>
> - Single-in, single-out: The first LVDS input receives the video stream,
>   and the bridge outputs it on the first parallel output. The second
>   LVDS input and the second parallel output are not used.
>
> - Single-in, dual-out: The first LVDS input receives the video stream,
>   and the bridge splits even- and odd-numbered pixels and outputs them
>   on the first and second parallel outputs. The second LVDS input is not
>   used.
>
> - Dual-in, single-out: The two LVDS inputs are used in dual-link mode,
>   and the bridge combines the even- and odd-numbered pixels and outputs
>   them on the first parallel output. The second parallel output is not
>   used.
>
> - Dual-in, dual-out: The two LVDS inputs are used in dual-link mode,
>   and the bridge outputs the even- and odd-numbered pixels on the first
>   parallel output.

and the second?

> The operating mode is selected by two input pins of the bridge, which
> are connected to DIP switches on the development boards I use. The mode
> is thus fixed from a Linux point of view.

Can the state of these switches be read from software?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v2 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation
  2019-05-11 21:06 ` [PATCH v2 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation Laurent Pinchart
@ 2019-05-12  8:58   ` Geert Uytterhoeven
  2019-05-12 10:22     ` Laurent Pinchart
  2019-05-14 20:17   ` Rob Herring
  1 sibling, 1 reply; 25+ messages in thread
From: Geert Uytterhoeven @ 2019-05-12  8:58 UTC (permalink / raw)
  To: Laurent Pinchart
  Cc: DRI Development, Linux-Renesas, Kieran Bingham,
	open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS,
	Jacopo Mondi

Hi Laurent,

On Sat, May 11, 2019 at 11:07 PM Laurent Pinchart
<laurent.pinchart+renesas@ideasonboard.com> wrote:
> The THC63LVD1024 LVDS decoder can operate in two modes, single-link or
> dual-link. In dual-link mode both input ports are used to carry even-
> and odd-numbered pixels separately. Document this in the DT bindings,
> along with the related rules governing port and usage.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> ---
>  .../bindings/display/bridge/thine,thc63lvd1024.txt          | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt b/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
> index 37f0c04d5a28..d17d1e5820d7 100644
> --- a/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
> +++ b/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
> @@ -28,6 +28,12 @@ Optional video port nodes:
>  - port@1: Second LVDS input port
>  - port@3: Second digital CMOS/TTL parallel output
>
> +The device can operate in single-link mode or dual-link mode. In single-link
> +mode, all pixels are received on port@0, and port@1 shall not contain any
> +endpoint. In dual-link mode, even-numbered pixels are received on port@0 and
> +odd-numbered pixels on port@1, and both port@0 and port@1 shall contain
> +endpoints.

This describes single/dual input.
Does single/dual output need to be described, too?

BTW, I see the second input/output set is optional, wile the first set
is required.  Could it happen the hardware is wired for the second
set only?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support
  2019-05-12  8:55 ` [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Geert Uytterhoeven
@ 2019-05-12 10:15   ` Laurent Pinchart
  0 siblings, 0 replies; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-12 10:15 UTC (permalink / raw)
  To: Geert Uytterhoeven
  Cc: Laurent Pinchart, DRI Development, Linux-Renesas, Kieran Bingham,
	Andrzej Hajda,
	open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS,
	Jacopo Mondi

Hi Geert,

On Sun, May 12, 2019 at 10:55:20AM +0200, Geert Uytterhoeven wrote:
> On Sat, May 11, 2019 at 11:07 PM Laurent Pinchart wrote:
> > On the receiving side, the THC63LVD1024 LVDS-to-parallel bridge has two
> > LVDS inputs and two parallel outputs. It can operate in four different
> > modes:
> >
> > - Single-in, single-out: The first LVDS input receives the video stream,
> >   and the bridge outputs it on the first parallel output. The second
> >   LVDS input and the second parallel output are not used.
> >
> > - Single-in, dual-out: The first LVDS input receives the video stream,
> >   and the bridge splits even- and odd-numbered pixels and outputs them
> >   on the first and second parallel outputs. The second LVDS input is not
> >   used.
> >
> > - Dual-in, single-out: The two LVDS inputs are used in dual-link mode,
> >   and the bridge combines the even- and odd-numbered pixels and outputs
> >   them on the first parallel output. The second parallel output is not
> >   used.
> >
> > - Dual-in, dual-out: The two LVDS inputs are used in dual-link mode,
> >   and the bridge outputs the even- and odd-numbered pixels on the first
> >   parallel output.
> 
> and the second?

I should have read "on the first and second parallel outputs
respectively" indeed.

> > The operating mode is selected by two input pins of the bridge, which
> > are connected to DIP switches on the development boards I use. The mode
> > is thus fixed from a Linux point of view.
> 
> Can the state of these switches be read from software?

Unfortunately not :-(

-- 
Regards,

Laurent Pinchart

^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v2 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation
  2019-05-12  8:58   ` Geert Uytterhoeven
@ 2019-05-12 10:22     ` Laurent Pinchart
  0 siblings, 0 replies; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-12 10:22 UTC (permalink / raw)
  To: Geert Uytterhoeven
  Cc: Laurent Pinchart, DRI Development, Linux-Renesas, Kieran Bingham,
	open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS,
	Jacopo Mondi

Hi Geert,

On Sun, May 12, 2019 at 10:58:54AM +0200, Geert Uytterhoeven wrote:
> On Sat, May 11, 2019 at 11:07 PM Laurent Pinchart wrote:
> > The THC63LVD1024 LVDS decoder can operate in two modes, single-link or
> > dual-link. In dual-link mode both input ports are used to carry even-
> > and odd-numbered pixels separately. Document this in the DT bindings,
> > along with the related rules governing port and usage.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> > Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > ---
> >  .../bindings/display/bridge/thine,thc63lvd1024.txt          | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt b/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
> > index 37f0c04d5a28..d17d1e5820d7 100644
> > --- a/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
> > +++ b/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
> > @@ -28,6 +28,12 @@ Optional video port nodes:
> >  - port@1: Second LVDS input port
> >  - port@3: Second digital CMOS/TTL parallel output
> >
> > +The device can operate in single-link mode or dual-link mode. In single-link
> > +mode, all pixels are received on port@0, and port@1 shall not contain any
> > +endpoint. In dual-link mode, even-numbered pixels are received on port@0 and
> > +odd-numbered pixels on port@1, and both port@0 and port@1 shall contain
> > +endpoints.
> 
> This describes single/dual input.
> Does single/dual output need to be described, too?

Jacopo asked the same question on v1 :-) Dual-output should be described
as well, but as I have no hardware setup where to test that, I decided
to leave it out of the DT bindings to start with, as it's generally a
bad idea to specify untested DT bindings (as in having no end-to-end
implementation). I don't think it will be a big deal though, there is
already a port for the second output, it should just be a matter of
connecting it.

> BTW, I see the second input/output set is optional, wile the first set
> is required.  Could it happen the hardware is wired for the second
> set only?

Not to my knowledge. In dual-in, dual-out the two input/output pairs are
not independent, the two inputs are used together to create a higher
bandwidth link, and the odd- and even-pixels are then sent to separate
routes.

-- 
Regards,

Laurent Pinchart

^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v2 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation
  2019-05-11 21:06 ` [PATCH v2 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation Laurent Pinchart
  2019-05-12  8:58   ` Geert Uytterhoeven
@ 2019-05-14 20:17   ` Rob Herring
  1 sibling, 0 replies; 25+ messages in thread
From: Rob Herring @ 2019-05-14 20:17 UTC (permalink / raw)
  To: Laurent Pinchart
  Cc: dri-devel, linux-renesas-soc, Kieran Bingham, devicetree, Jacopo Mondi

On Sun, 12 May 2019 00:06:54 +0300, Laurent Pinchart wrote:
> The THC63LVD1024 LVDS decoder can operate in two modes, single-link or
> dual-link. In dual-link mode both input ports are used to carry even-
> and odd-numbered pixels separately. Document this in the DT bindings,
> along with the related rules governing port and usage.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> ---
>  .../bindings/display/bridge/thine,thc63lvd1024.txt          | 6 ++++++
>  1 file changed, 6 insertions(+)
> 

Reviewed-by: Rob Herring <robh@kernel.org>

^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v2 03/10] drm: bridge: thc63: Report input bus mode through bridge timings
  2019-05-11 21:06 ` [PATCH v2 03/10] drm: bridge: thc63: Report input bus mode through bridge timings Laurent Pinchart
@ 2019-05-28  9:05   ` Jacopo Mondi
  0 siblings, 0 replies; 25+ messages in thread
From: Jacopo Mondi @ 2019-05-28  9:05 UTC (permalink / raw)
  To: Laurent Pinchart
  Cc: dri-devel, linux-renesas-soc, Kieran Bingham, Andrzej Hajda,
	Jacopo Mondi

[-- Attachment #1: Type: text/plain, Size: 4194 bytes --]

Hi Laurent,

On Sun, May 12, 2019 at 12:06:55AM +0300, Laurent Pinchart wrote:
> Set a drm_bridge_timings in the drm_bridge, and use it to report the
> input bus mode (single-link or dual-link). The other fields of the
> timings structure are kept to 0 as they do not apply to LVDS buses.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
> Changes since v1:
>
> - Ignore disabled remote device
> ---
>  drivers/gpu/drm/bridge/thc63lvd1024.c | 54 +++++++++++++++++++++------
>  1 file changed, 43 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/thc63lvd1024.c b/drivers/gpu/drm/bridge/thc63lvd1024.c
> index b083a740565c..709dd28b43d6 100644
> --- a/drivers/gpu/drm/bridge/thc63lvd1024.c
> +++ b/drivers/gpu/drm/bridge/thc63lvd1024.c
> @@ -31,6 +31,8 @@ struct thc63_dev {
>
>  	struct drm_bridge bridge;
>  	struct drm_bridge *next;
> +
> +	struct drm_bridge_timings timings;
>  };
>
>  static inline struct thc63_dev *to_thc63(struct drm_bridge *bridge)
> @@ -48,15 +50,28 @@ static int thc63_attach(struct drm_bridge *bridge)
>  static enum drm_mode_status thc63_mode_valid(struct drm_bridge *bridge,
>  					const struct drm_display_mode *mode)
>  {
> +	struct thc63_dev *thc63 = to_thc63(bridge);
> +	unsigned int min_freq;
> +	unsigned int max_freq;
> +
>  	/*
> -	 * The THC63LVD1024 clock frequency range is 8 to 135 MHz in single-in
> -	 * mode. Note that the limits are different in dual-in, single-out mode,
> -	 * and will need to be adjusted accordingly.
> +	 * The THC63LVD1024 pixel rate range is 8 to 135 MHz in all modes but
> +	 * dual-in, single-out where it is 40 to 150 MHz. As dual-in, dual-out
> +	 * isn't supported by the driver yet, simply derive the limits from the
> +	 * input mode.
>  	 */
> -	if (mode->clock < 8000)
> +	if (thc63->timings.dual_link) {
> +		min_freq = 40000;
> +		max_freq = 150000;
> +	} else {
> +		min_freq = 8000;
> +		max_freq = 135000;
> +	}
> +
> +	if (mode->clock < min_freq)
>  		return MODE_CLOCK_LOW;
>
> -	if (mode->clock > 135000)
> +	if (mode->clock > max_freq)
>  		return MODE_CLOCK_HIGH;

I would have made a separate patch for this bit, anyway, verified
against the THC631024 manual, and this matches my understanding.

>
>  	return MODE_OK;
> @@ -101,19 +116,19 @@ static const struct drm_bridge_funcs thc63_bridge_func = {
>
>  static int thc63_parse_dt(struct thc63_dev *thc63)
>  {
> -	struct device_node *thc63_out;
> +	struct device_node *endpoint;
>  	struct device_node *remote;
>
> -	thc63_out = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
> -						  THC63_RGB_OUT0, -1);
> -	if (!thc63_out) {
> +	endpoint = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
> +						 THC63_RGB_OUT0, -1);
> +	if (!endpoint) {
>  		dev_err(thc63->dev, "Missing endpoint in port@%u\n",
>  			THC63_RGB_OUT0);
>  		return -ENODEV;
>  	}
>
> -	remote = of_graph_get_remote_port_parent(thc63_out);
> -	of_node_put(thc63_out);
> +	remote = of_graph_get_remote_port_parent(endpoint);
> +	of_node_put(endpoint);
>  	if (!remote) {
>  		dev_err(thc63->dev, "Endpoint in port@%u unconnected\n",
>  			THC63_RGB_OUT0);
> @@ -132,6 +147,22 @@ static int thc63_parse_dt(struct thc63_dev *thc63)
>  	if (!thc63->next)
>  		return -EPROBE_DEFER;
>
> +	endpoint = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
> +						 THC63_LVDS_IN1, -1);
> +	if (endpoint) {
> +		remote = of_graph_get_remote_port_parent(endpoint);
> +		of_node_put(endpoint);
> +
> +		if (remote) {
> +			if (of_device_is_available(remote))
> +				thc63->timings.dual_link = true;
> +			of_node_put(remote);
> +		}
> +	}
> +
> +	dev_dbg(thc63->dev, "operating in %s-link mode\n",
> +		thc63->timings.dual_link ? "dual" : "single");
> +

Fine, thanks for having addressed comments on the RFC.

Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

Thanks
   j

>  	return 0;
>  }
>
> @@ -188,6 +219,7 @@ static int thc63_probe(struct platform_device *pdev)
>  	thc63->bridge.driver_private = thc63;
>  	thc63->bridge.of_node = pdev->dev.of_node;
>  	thc63->bridge.funcs = &thc63_bridge_func;
> +	thc63->bridge.timings = &thc63->timings;
>
>  	drm_bridge_add(&thc63->bridge);
>
> --
> Regards,
>
> Laurent Pinchart
>

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^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v2 04/10] dt-bindings: display: renesas: lvds: Add renesas,companion property
  2019-05-11 21:06 ` [PATCH v2 04/10] dt-bindings: display: renesas: lvds: Add renesas,companion property Laurent Pinchart
@ 2019-05-28  9:28   ` Jacopo Mondi
  2019-05-28 12:30     ` Laurent Pinchart
  0 siblings, 1 reply; 25+ messages in thread
From: Jacopo Mondi @ 2019-05-28  9:28 UTC (permalink / raw)
  To: Laurent Pinchart; +Cc: dri-devel, linux-renesas-soc, Kieran Bingham, devicetree

[-- Attachment #1: Type: text/plain, Size: 1918 bytes --]

Hi Laurent,

On Sun, May 12, 2019 at 12:06:56AM +0300, Laurent Pinchart wrote:
> Add a new optional renesas,companion property to point to the companion
> LVDS encoder. This is used to support dual-link operation where the main
> LVDS encoder splits even-numbered and odd-numbered pixels between the
> two LVDS encoders.
>
> The new property doesn't control the mode of operation, it only
> describes the relationship between the master and companion LVDS
> encoders.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
> Changes since v1:
>
> - Fixed typo
> ---
>  .../devicetree/bindings/display/bridge/renesas,lvds.txt     | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt b/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt
> index 900a884ad9f5..f2cc01d54cbd 100644
> --- a/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt
> +++ b/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt
> @@ -45,6 +45,12 @@ OF graph bindings specified in Documentation/devicetree/bindings/graph.txt.
>
>  Each port shall have a single endpoint.
>
> +Optional properties:
> +
> +- renesas,companion : phandle to the companion LVDS encoder. This property is
> +  valid for the first LVDS encoder on D3 and E3 SoCs only, and points to the
> +  second encoder to be used as a companion in dual-link mode.
> +

If I got this right, the property does not enable dual-link
operations by itself, but it needs the next bridge to be operating in
dual link mode (ie. has both LVDS0 and LVDS1 output connected to its
input ports). Is it worth describing it here (or at least clarify the
the property alone does not enable dual link operations).

Apart from that
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

Thanks
   j


>
>  Example:
>
> --
> Regards,
>
> Laurent Pinchart
>

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^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v2 06/10] drm: rcar-du: lvds: Add support for dual-link mode
  2019-05-11 21:06 ` [PATCH v2 06/10] drm: rcar-du: lvds: Add support for dual-link mode Laurent Pinchart
@ 2019-05-28  9:35   ` Jacopo Mondi
  2019-05-28 12:46     ` Laurent Pinchart
  0 siblings, 1 reply; 25+ messages in thread
From: Jacopo Mondi @ 2019-05-28  9:35 UTC (permalink / raw)
  To: Laurent Pinchart
  Cc: dri-devel, linux-renesas-soc, Kieran Bingham, Jacopo Mondi

[-- Attachment #1: Type: text/plain, Size: 7913 bytes --]

Hi Laurent,
 a small note.

On Sun, May 12, 2019 at 12:06:58AM +0300, Laurent Pinchart wrote:
> In dual-link mode the LVDS0 encoder transmits even-numbered pixels, and
> sends odd-numbered pixels to the LVDS1 encoder for transmission on a
> separate link.
>
> To implement support for this mode of operation, determine if the LVDS
> connection operates in dual-link mode by querying the next device in the
> pipeline, locate the companion encoder, and control it directly through
> its bridge operations.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> ---
>  drivers/gpu/drm/rcar-du/rcar_lvds.c | 104 ++++++++++++++++++++++++----
>  drivers/gpu/drm/rcar-du/rcar_lvds.h |   5 ++
>  2 files changed, 96 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> index a331f0c32187..f7e4710fe33f 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> @@ -66,6 +66,9 @@ struct rcar_lvds {
>
>  	struct drm_display_mode display_mode;
>  	enum rcar_lvds_mode mode;
> +
> +	struct drm_bridge *companion;
> +	bool dual_link;
>  };
>
>  #define bridge_to_rcar_lvds(bridge) \
> @@ -400,11 +403,6 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
>  {
>  	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
>  	const struct drm_display_mode *mode = &lvds->display_mode;
> -	/*
> -	 * FIXME: We should really retrieve the CRTC through the state, but how
> -	 * do we get a state pointer?
> -	 */
> -	struct drm_crtc *crtc = lvds->bridge.encoder->crtc;
>  	u32 lvdhcr;
>  	u32 lvdcr0;
>  	int ret;
> @@ -413,6 +411,10 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
>  	if (ret < 0)
>  		return;
>
> +	/* Enable the companion LVDS encoder in dual-link mode. */
> +	if (lvds->dual_link && lvds->companion)
> +		lvds->companion->funcs->enable(lvds->companion);
> +
>  	/*
>  	 * Hardcode the channels and control signals routing for now.
>  	 *
> @@ -435,17 +437,33 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
>  	rcar_lvds_write(lvds, LVDCHCR, lvdhcr);
>
>  	if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK) {
> -		/* Disable dual-link mode. */
> -		rcar_lvds_write(lvds, LVDSTRIPE, 0);
> +		/*
> +		 * Configure vertical stripe based on the mode of operation of
> +		 * the connected device.
> +		 */
> +		rcar_lvds_write(lvds, LVDSTRIPE,
> +				lvds->dual_link ? LVDSTRIPE_ST_ON : 0);
>  	}
>
> -	/* PLL clock configuration. */
> -	lvds->info->pll_setup(lvds, mode->clock * 1000);
> +	/*
> +	 * PLL clock configuration on all instances but the companion in
> +	 * dual-link mode.
> +	 */
> +	if (!lvds->dual_link || lvds->companion)
> +		lvds->info->pll_setup(lvds, mode->clock * 1000);
>
>  	/* Set the LVDS mode and select the input. */
>  	lvdcr0 = lvds->mode << LVDCR0_LVMD_SHIFT;
> -	if (drm_crtc_index(crtc) == 2)
> -		lvdcr0 |= LVDCR0_DUSEL;
> +
> +	if (lvds->bridge.encoder) {
> +		/*
> +		 * FIXME: We should really retrieve the CRTC through the state,
> +		 * but how do we get a state pointer?
> +		 */
> +		if (drm_crtc_index(lvds->bridge.encoder->crtc) == 2)
> +			lvdcr0 |= LVDCR0_DUSEL;
> +	}
> +
>  	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
>
>  	/* Turn all the channels on. */
> @@ -512,6 +530,10 @@ static void rcar_lvds_disable(struct drm_bridge *bridge)
>  	rcar_lvds_write(lvds, LVDCR1, 0);
>  	rcar_lvds_write(lvds, LVDPLLCR, 0);
>
> +	/* Disable the companion LVDS encoder in dual-link mode. */
> +	if (lvds->dual_link && lvds->companion)
> +		lvds->companion->funcs->disable(lvds->companion);
> +
>  	clk_disable_unprepare(lvds->clocks.mod);
>  }
>
> @@ -628,10 +650,54 @@ static const struct drm_bridge_funcs rcar_lvds_bridge_ops = {
>  	.mode_set = rcar_lvds_mode_set,
>  };
>
> +bool rcar_lvds_dual_link(struct drm_bridge *bridge)
> +{
> +	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
> +
> +	return lvds->dual_link;
> +}
> +EXPORT_SYMBOL_GPL(rcar_lvds_dual_link);
> +
>  /* -----------------------------------------------------------------------------
>   * Probe & Remove
>   */
>
> +static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
> +{
> +	const struct of_device_id *match;
> +	struct device_node *companion;
> +	struct device *dev = lvds->dev;
> +	int ret = 0;
> +
> +	/* Locate the companion LVDS encoder for dual-link operation, if any. */
> +	companion = of_parse_phandle(dev->of_node, "renesas,companion", 0);
> +	if (!companion)
> +		return -ENODEV;
> +
> +	/*
> +	 * Sanity check: the companion encoder must have the same compatible
> +	 * string.
> +	 */
> +	match = of_match_device(dev->driver->of_match_table, dev);
> +	if (!of_device_is_compatible(companion, match->compatible)) {
> +		ret = -ENODEV;
> +		goto done;
> +	}
> +
> +	lvds->companion = of_drm_find_bridge(companion);
> +	if (!lvds->companion) {
> +		ret = -EPROBE_DEFER;
> +		goto done;
> +	}
> +
> +	dev_dbg(dev, "Found companion encoder %pOF\n", companion);
> +
> +done:
> +	of_node_put(companion);
> +
> +	return ret;
> +}
> +
>  static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
>  {
>  	struct device_node *local_output = NULL;
> @@ -682,14 +748,26 @@ static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
>
>  	if (is_bridge) {
>  		lvds->next_bridge = of_drm_find_bridge(remote);
> -		if (!lvds->next_bridge)
> +		if (!lvds->next_bridge) {
>  			ret = -EPROBE_DEFER;
> +			goto done;
> +		}
> +
> +		if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK)
> +			lvds->dual_link = lvds->next_bridge->timings
> +					? lvds->next_bridge->timings->dual_link
> +					: false;
>  	} else {
>  		lvds->panel = of_drm_find_panel(remote);
> -		if (IS_ERR(lvds->panel))
> +		if (IS_ERR(lvds->panel)) {
>  			ret = PTR_ERR(lvds->panel);
> +			goto done;
> +		}
>  	}
>
> +	if (lvds->dual_link)
> +		ret = rcar_lvds_parse_dt_companion(lvds);

Looking at the error path here below, for E3/D3, -ENODEV gets
sanitized to return 0 as we want this method to return success even if
no endpoint is there, when using the LVDS encoder provided clock to
back-feed the DU.

This is not the case for the companion property imho. If the property is
specified, it should be sane and -ENODEV is worth being propagated to
the caller.

You could move the error handling bits in the error path:

	/*
	 * On D3/E3 the LVDS encoder provides a clock to the DU, which can be
	 * used for the DPAD output even when the LVDS output is not connected.
	 * Don't fail probe in that case as the DU will need the bridge to
	 * control the clock.
	 */
	if (lvds->info->quirks & RCAR_LVDS_QUIRK_EXT_PLL)
		return ret == -ENODEV ? 0 : ret;

before the of_node_put() sequences, and add one more label, to skip
the above part in case parse_dt_companion() fails.

Apart from this you can retain my tag if you like.
Thanks
   j

> +
>  done:
>  	of_node_put(local_output);
>  	of_node_put(remote_input);
> diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.h b/drivers/gpu/drm/rcar-du/rcar_lvds.h
> index a709cae1bc32..222ec0e60785 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_lvds.h
> +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.h
> @@ -15,6 +15,7 @@ struct drm_bridge;
>  #if IS_ENABLED(CONFIG_DRM_RCAR_LVDS)
>  int rcar_lvds_clk_enable(struct drm_bridge *bridge, unsigned long freq);
>  void rcar_lvds_clk_disable(struct drm_bridge *bridge);
> +bool rcar_lvds_dual_link(struct drm_bridge *bridge);
>  #else
>  static inline int rcar_lvds_clk_enable(struct drm_bridge *bridge,
>  				       unsigned long freq)
> @@ -22,6 +23,10 @@ static inline int rcar_lvds_clk_enable(struct drm_bridge *bridge,
>  	return -ENOSYS;
>  }
>  static inline void rcar_lvds_clk_disable(struct drm_bridge *bridge) { }
> +static inline bool rcar_lvds_dual_link(struct drm_bridge *bridge)
> +{
> +	return false;
> +}
>  #endif /* CONFIG_DRM_RCAR_LVDS */
>
>  #endif /* __RCAR_LVDS_H__ */
> --
> Regards,
>
> Laurent Pinchart
>

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* Re: [PATCH v2 07/10] drm: rcar-du: Skip LVDS1 output on Gen3 when using dual-link LVDS mode
  2019-05-11 21:06 ` [PATCH v2 07/10] drm: rcar-du: Skip LVDS1 output on Gen3 when using dual-link LVDS mode Laurent Pinchart
@ 2019-05-28  9:38   ` Jacopo Mondi
  0 siblings, 0 replies; 25+ messages in thread
From: Jacopo Mondi @ 2019-05-28  9:38 UTC (permalink / raw)
  To: Laurent Pinchart; +Cc: dri-devel, linux-renesas-soc, Kieran Bingham

[-- Attachment #1: Type: text/plain, Size: 2341 bytes --]

HI Laurent,

On Sun, May 12, 2019 at 12:06:59AM +0300, Laurent Pinchart wrote:
> In dual-link LVDS mode, the LVDS1 encoder is used as a companion for
> LVDS0, and both encoders transmit data from DU0. The LVDS1 output of DU1
> can't be used in that case, don't create an encoder and connector for
> it.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
>  drivers/gpu/drm/rcar-du/rcar_du_encoder.c | 12 ++++++++++++
>  drivers/gpu/drm/rcar-du/rcar_du_kms.c     |  2 +-
>  2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> index 6c91753af7bc..fe046d194944 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> @@ -16,6 +16,7 @@
>  #include "rcar_du_drv.h"
>  #include "rcar_du_encoder.h"
>  #include "rcar_du_kms.h"
> +#include "rcar_lvds.h"
>
>  /* -----------------------------------------------------------------------------
>   * Encoder
> @@ -97,6 +98,17 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>  		}
>  	}
>
> +	/*
> +	 * On Gen3 skip the LVDS1 output if the LVDS1 encoder is used as a
> +	 * companion for LVDS0 in dual-link mode.
> +	 */
> +	if (rcdu->info->gen >= 3 && output == RCAR_DU_OUTPUT_LVDS1) {
> +		if (bridge && rcar_lvds_dual_link(bridge)) {

If you get here, 'bridge' is guaranteed to be valid.

> +			ret = -ENOLINK;
> +			goto done;
> +		}
> +	}
> +
>  	ret = drm_encoder_init(rcdu->ddev, encoder, &encoder_funcs,
>  			       DRM_MODE_ENCODER_NONE, NULL);
>  	if (ret < 0)
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> index f8f7fff34dff..95c81e59e2f1 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> @@ -378,7 +378,7 @@ static int rcar_du_encoders_init_one(struct rcar_du_device *rcdu,
>  	}
>
>  	ret = rcar_du_encoder_init(rcdu, output, entity);
> -	if (ret && ret != -EPROBE_DEFER)
> +	if (ret && ret != -EPROBE_DEFER && ret != -ENOLINK)

Apart from the minor above
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

Thanks
  j

>  		dev_warn(rcdu->dev,
>  			 "failed to initialize encoder %pOF on output %u (%d), skipping\n",
>  			 entity, output, ret);
> --
> Regards,
>
> Laurent Pinchart
>

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* Re: [PATCH v2 08/10] arm64: dts: renesas: r8a7799[05]: Point LVDS0 to its companion LVDS1
  2019-05-11 21:07 ` [PATCH v2 08/10] arm64: dts: renesas: r8a7799[05]: Point LVDS0 to its companion LVDS1 Laurent Pinchart
@ 2019-05-28  9:39   ` Jacopo Mondi
  0 siblings, 0 replies; 25+ messages in thread
From: Jacopo Mondi @ 2019-05-28  9:39 UTC (permalink / raw)
  To: Laurent Pinchart; +Cc: dri-devel, linux-renesas-soc, Kieran Bingham

[-- Attachment #1: Type: text/plain, Size: 1449 bytes --]

Hi Laurent,

On Sun, May 12, 2019 at 12:07:00AM +0300, Laurent Pinchart wrote:
> Add the new renesas,companion property to the LVDS0 node to point to the
> companion LVDS encoder LVDS1.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Provided this does not enable dual-link operations by default:
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

Thanks
   j

> ---
>  arch/arm64/boot/dts/renesas/r8a77990.dtsi | 2 ++
>  arch/arm64/boot/dts/renesas/r8a77995.dtsi | 2 ++
>  2 files changed, 4 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/renesas/r8a77990.dtsi b/arch/arm64/boot/dts/renesas/r8a77990.dtsi
> index d2ad665fe2d9..b52e3fdb5fca 100644
> --- a/arch/arm64/boot/dts/renesas/r8a77990.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r8a77990.dtsi
> @@ -1731,6 +1731,8 @@
>  			resets = <&cpg 727>;
>  			status = "disabled";
>
> +			renesas,companion = <&lvds1>;
> +
>  			ports {
>  				#address-cells = <1>;
>  				#size-cells = <0>;
> diff --git a/arch/arm64/boot/dts/renesas/r8a77995.dtsi b/arch/arm64/boot/dts/renesas/r8a77995.dtsi
> index 5bf3af246e14..94b5177eb152 100644
> --- a/arch/arm64/boot/dts/renesas/r8a77995.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r8a77995.dtsi
> @@ -1038,6 +1038,8 @@
>  			resets = <&cpg 727>;
>  			status = "disabled";
>
> +			renesas,companion = <&lvds1>;
> +
>  			ports {
>  				#address-cells = <1>;
>  				#size-cells = <0>;
> --
> Regards,
>
> Laurent Pinchart
>

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* Re: [PATCH v2 05/10] drm: rcar-du: lvds: Remove LVDS double-enable checks
  2019-05-11 21:06 ` [PATCH v2 05/10] drm: rcar-du: lvds: Remove LVDS double-enable checks Laurent Pinchart
@ 2019-05-28  9:40   ` Jacopo Mondi
  0 siblings, 0 replies; 25+ messages in thread
From: Jacopo Mondi @ 2019-05-28  9:40 UTC (permalink / raw)
  To: Laurent Pinchart; +Cc: dri-devel, linux-renesas-soc, Kieran Bingham

[-- Attachment #1: Type: text/plain, Size: 3189 bytes --]

Hi Laurent,

On Sun, May 12, 2019 at 12:06:57AM +0300, Laurent Pinchart wrote:
> The DRM core and DU driver guarantee that the LVDS bridge will not be
> double-enabled or double-disabled. Remove the corresponding unnecessary
> checks.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

Thanks
  j

> ---
>  drivers/gpu/drm/rcar-du/rcar_lvds.c | 19 -------------------
>  1 file changed, 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> index 620b51aab291..a331f0c32187 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> @@ -63,7 +63,6 @@ struct rcar_lvds {
>  		struct clk *extal;		/* External clock */
>  		struct clk *dotclkin[2];	/* External DU clocks */
>  	} clocks;
> -	bool enabled;
>
>  	struct drm_display_mode display_mode;
>  	enum rcar_lvds_mode mode;
> @@ -368,15 +367,12 @@ int rcar_lvds_clk_enable(struct drm_bridge *bridge, unsigned long freq)
>
>  	dev_dbg(lvds->dev, "enabling LVDS PLL, freq=%luHz\n", freq);
>
> -	WARN_ON(lvds->enabled);
> -
>  	ret = clk_prepare_enable(lvds->clocks.mod);
>  	if (ret < 0)
>  		return ret;
>
>  	__rcar_lvds_pll_setup_d3_e3(lvds, freq, true);
>
> -	lvds->enabled = true;
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(rcar_lvds_clk_enable);
> @@ -390,13 +386,9 @@ void rcar_lvds_clk_disable(struct drm_bridge *bridge)
>
>  	dev_dbg(lvds->dev, "disabling LVDS PLL\n");
>
> -	WARN_ON(!lvds->enabled);
> -
>  	rcar_lvds_write(lvds, LVDPLLCR, 0);
>
>  	clk_disable_unprepare(lvds->clocks.mod);
> -
> -	lvds->enabled = false;
>  }
>  EXPORT_SYMBOL_GPL(rcar_lvds_clk_disable);
>
> @@ -417,8 +409,6 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
>  	u32 lvdcr0;
>  	int ret;
>
> -	WARN_ON(lvds->enabled);
> -
>  	ret = clk_prepare_enable(lvds->clocks.mod);
>  	if (ret < 0)
>  		return;
> @@ -507,16 +497,12 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
>  		drm_panel_prepare(lvds->panel);
>  		drm_panel_enable(lvds->panel);
>  	}
> -
> -	lvds->enabled = true;
>  }
>
>  static void rcar_lvds_disable(struct drm_bridge *bridge)
>  {
>  	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
>
> -	WARN_ON(!lvds->enabled);
> -
>  	if (lvds->panel) {
>  		drm_panel_disable(lvds->panel);
>  		drm_panel_unprepare(lvds->panel);
> @@ -527,8 +513,6 @@ static void rcar_lvds_disable(struct drm_bridge *bridge)
>  	rcar_lvds_write(lvds, LVDPLLCR, 0);
>
>  	clk_disable_unprepare(lvds->clocks.mod);
> -
> -	lvds->enabled = false;
>  }
>
>  static bool rcar_lvds_mode_fixup(struct drm_bridge *bridge,
> @@ -592,8 +576,6 @@ static void rcar_lvds_mode_set(struct drm_bridge *bridge,
>  {
>  	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
>
> -	WARN_ON(lvds->enabled);
> -
>  	lvds->display_mode = *adjusted_mode;
>
>  	rcar_lvds_get_lvds_mode(lvds);
> @@ -793,7 +775,6 @@ static int rcar_lvds_probe(struct platform_device *pdev)
>
>  	lvds->dev = &pdev->dev;
>  	lvds->info = of_device_get_match_data(&pdev->dev);
> -	lvds->enabled = false;
>
>  	ret = rcar_lvds_parse_dt(lvds);
>  	if (ret < 0)
> --
> Regards,
>
> Laurent Pinchart
>

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* Re: [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support
  2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
                   ` (10 preceding siblings ...)
  2019-05-12  8:55 ` [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Geert Uytterhoeven
@ 2019-05-28 10:20 ` Jacopo Mondi
  11 siblings, 0 replies; 25+ messages in thread
From: Jacopo Mondi @ 2019-05-28 10:20 UTC (permalink / raw)
  To: Laurent Pinchart
  Cc: dri-devel, linux-renesas-soc, Kieran Bingham, Andrzej Hajda,
	devicetree, Jacopo Mondi

[-- Attachment #1: Type: text/plain, Size: 6274 bytes --]

Hi Laurent,

On Sun, May 12, 2019 at 12:06:52AM +0300, Laurent Pinchart wrote:
> Hello everybody,
>
> This patch series implements support for LVDS dual-link mode in the
> R-Car DU and R-Car LVDS encoder drivers, and well as in the thc63lvd1024
> LVDS decoder driver.
>
> LVDS dual-link is a mode of operation where two individual LVDS links
> are operated together to carry even- and odd-numbered pixels separately.
> This doubles the possible bandwidth of the video transmission. Both the
> transmitter and the receiver need to support this mode of operation.
>
> The R-Car D3 and E3 SoCs include two independent LVDS encoders that can
> be grouped together to operate in dual-link mode. When used separately,
> the LVDS encoders are connected to two different CRTCs and transmit
> independent video streams. When used in dual-link mode, the first LVDS
> encoder is connected to the first CRTC, and split even- and odd-numbered
> pixels. It transmits half of the pixels on its LVDS output, and sends
> the other half to the second LVDS encoder for transmittion over the
> second LVDS link. The second LVDS encoder thus operates under control of
> the first one, and isn't connected directly to a CRTC.
>
> On the receiving side, the THC63LVD1024 LVDS-to-parallel bridge has two
> LVDS inputs and two parallel outputs. It can operate in four different
> modes:
>
> - Single-in, single-out: The first LVDS input receives the video stream,
>   and the bridge outputs it on the first parallel output. The second
>   LVDS input and the second parallel output are not used.
>
> - Single-in, dual-out: The first LVDS input receives the video stream,
>   and the bridge splits even- and odd-numbered pixels and outputs them
>   on the first and second parallel outputs. The second LVDS input is not
>   used.
>
> - Dual-in, single-out: The two LVDS inputs are used in dual-link mode,
>   and the bridge combines the even- and odd-numbered pixels and outputs
>   them on the first parallel output. The second parallel output is not
>   used.
>
> - Dual-in, dual-out: The two LVDS inputs are used in dual-link mode,
>   and the bridge outputs the even- and odd-numbered pixels on the first
>   parallel output.
>
> The operating mode is selected by two input pins of the bridge, which
> are connected to DIP switches on the development boards I use. The mode
> is thus fixed from a Linux point of view.
>
> Patch 01/10 adds a new dual_link boolen field to the drm_bridge_timings
> structure to let bridges report their LVDS mode of operation. Patch
> 02/10 clarifies the THC63LVD1024 DT bindings to document dual-link
> operation, and patch 03/10 implements dual-link support in the
> thc64lvd1024 bridge driver by setting the drm_bridge_timings dual_link
> field according to the mode selected through DT.
>
> Patch 04/10 extends the R-Car LVDS DT bindings to specify the companion
> LVDS encoder for dual-link operation. Patches 05/10 then performs a
> small cleanup in the LVDS encoder driver. Patch 06/10 implements
> dual-link support in the LVDS encoder driver, which involves retrieving
> the operation mode from the LVDS receiver, locating the companion LVDS
> encoder, and configuring both encoders when dual-link operation is
> desired. The API towards the DU driver is also extended to report the
> mode of operation.
>
> Patch 07/10 implements dual-link mode support in the DU driver. There is
> no specific configuration to be performed there, as dual-link is fully
> implemented in the LVDS encoder driver, but the DU driver has to skip
> creation of the DRM encoder and connector related to the second LVDS
> encoder when dual-link is used, as the second LVDS encoder operates as a
> slave of the first one, transparently from a CRTC (and thus userspace)
> perspective.
>
> Patch 08/10 specifies the companion LVDS encoder in the D3 and E3 DT
> bindings. This by itself doesn't enable dual-link mode, the LVDS0
> encoder is still connected to the HDMI output through LVDS receiver, and
> the LVDS1 encoder is not used. Patches 09/10 and 10/10, not intended to
> be merged, enable dual-link operation for the D3 and E3 boards for
> testing and require flipping DIP switches on the boards.
>
> The patches are based on top of my drm/du/next branch, and are available
> for convenience at
>
>         git://linuxtv.org/pinchartl/media.git drm/du/lvds/dual-link
>
> They have been tested successfully on the D3 Draak board. I expect them
> to work on E3 as well, but I don't have access to an Ebisu board to test
> this.

I have now tested the series on E3 Ebisu board using kms-tests using
the HDMI output and I confirm it works as expected.

For the whole series:
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

Thanks
  j

>
> Laurent Pinchart (10):
>   drm: bridge: Add dual_link field to the drm_bridge_timings structure
>   dt-bindings: display: bridge: thc63lvd1024: Document dual-link
>     operation
>   drm: bridge: thc63: Report input bus mode through bridge timings
>   dt-bindings: display: renesas: lvds: Add renesas,companion property
>   drm: rcar-du: lvds: Remove LVDS double-enable checks
>   drm: rcar-du: lvds: Add support for dual-link mode
>   drm: rcar-du: Skip LVDS1 output on Gen3 when using dual-link LVDS mode
>   arm64: dts: renesas: r8a7799[05]: Point LVDS0 to its companion LVDS1
>   [HACK] arm64: dts: renesas: draak: Enable LVDS dual-link operation
>   [HACK] arm64: dts: renesas: ebisu: Enable LVDS dual-link operation
>
>  .../bindings/display/bridge/renesas,lvds.txt  |   6 +
>  .../display/bridge/thine,thc63lvd1024.txt     |   6 +
>  .../arm64/boot/dts/renesas/r8a77990-ebisu.dts |  21 ++-
>  arch/arm64/boot/dts/renesas/r8a77990.dtsi     |   2 +
>  .../arm64/boot/dts/renesas/r8a77995-draak.dts |  21 ++-
>  arch/arm64/boot/dts/renesas/r8a77995.dtsi     |   2 +
>  drivers/gpu/drm/bridge/thc63lvd1024.c         |  54 ++++++--
>  drivers/gpu/drm/rcar-du/rcar_du_encoder.c     |  12 ++
>  drivers/gpu/drm/rcar-du/rcar_du_kms.c         |   2 +-
>  drivers/gpu/drm/rcar-du/rcar_lvds.c           | 123 +++++++++++++-----
>  drivers/gpu/drm/rcar-du/rcar_lvds.h           |   5 +
>  include/drm/drm_bridge.h                      |   8 ++
>  12 files changed, 214 insertions(+), 48 deletions(-)
>
> --
> Regards,
>
> Laurent Pinchart
>

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* Re: [PATCH v2 04/10] dt-bindings: display: renesas: lvds: Add renesas,companion property
  2019-05-28  9:28   ` Jacopo Mondi
@ 2019-05-28 12:30     ` Laurent Pinchart
  0 siblings, 0 replies; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-28 12:30 UTC (permalink / raw)
  To: Jacopo Mondi
  Cc: Laurent Pinchart, dri-devel, linux-renesas-soc, Kieran Bingham,
	devicetree

Hi Jacopo,

On Tue, May 28, 2019 at 11:28:47AM +0200, Jacopo Mondi wrote:
> On Sun, May 12, 2019 at 12:06:56AM +0300, Laurent Pinchart wrote:
> > Add a new optional renesas,companion property to point to the companion
> > LVDS encoder. This is used to support dual-link operation where the main
> > LVDS encoder splits even-numbered and odd-numbered pixels between the
> > two LVDS encoders.
> >
> > The new property doesn't control the mode of operation, it only
> > describes the relationship between the master and companion LVDS
> > encoders.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> > ---
> > Changes since v1:
> >
> > - Fixed typo
> > ---
> >  .../devicetree/bindings/display/bridge/renesas,lvds.txt     | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt b/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt
> > index 900a884ad9f5..f2cc01d54cbd 100644
> > --- a/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt
> > +++ b/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt
> > @@ -45,6 +45,12 @@ OF graph bindings specified in Documentation/devicetree/bindings/graph.txt.
> >
> >  Each port shall have a single endpoint.
> >
> > +Optional properties:
> > +
> > +- renesas,companion : phandle to the companion LVDS encoder. This property is
> > +  valid for the first LVDS encoder on D3 and E3 SoCs only, and points to the
> > +  second encoder to be used as a companion in dual-link mode.
> > +
> 
> If I got this right, the property does not enable dual-link
> operations by itself, but it needs the next bridge to be operating in
> dual link mode (ie. has both LVDS0 and LVDS1 output connected to its
> input ports).

Correct.

> Is it worth describing it here (or at least clarify the the property
> alone does not enable dual link operations).

How about the following ?

- renesas,companion : phandle to the companion LVDS encoder. This property is
  mandatory for the first LVDS encoder on D3 and E3 SoCs, and shall point to 
  the second encoder to be used as a companion in dual-link mode. It shall not 
  be set for any other LVDS encoder.

> Apart from that
> Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

-- 
Regards,

Laurent Pinchart

^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v2 06/10] drm: rcar-du: lvds: Add support for dual-link mode
  2019-05-28  9:35   ` Jacopo Mondi
@ 2019-05-28 12:46     ` Laurent Pinchart
  0 siblings, 0 replies; 25+ messages in thread
From: Laurent Pinchart @ 2019-05-28 12:46 UTC (permalink / raw)
  To: Jacopo Mondi
  Cc: Laurent Pinchart, dri-devel, linux-renesas-soc, Kieran Bingham,
	Jacopo Mondi

Hi Jacopo,

On Tue, May 28, 2019 at 11:35:50AM +0200, Jacopo Mondi wrote:
> Hi Laurent,
>  a small note.
> 
> On Sun, May 12, 2019 at 12:06:58AM +0300, Laurent Pinchart wrote:
> > In dual-link mode the LVDS0 encoder transmits even-numbered pixels, and
> > sends odd-numbered pixels to the LVDS1 encoder for transmission on a
> > separate link.
> >
> > To implement support for this mode of operation, determine if the LVDS
> > connection operates in dual-link mode by querying the next device in the
> > pipeline, locate the companion encoder, and control it directly through
> > its bridge operations.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> > Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > ---
> >  drivers/gpu/drm/rcar-du/rcar_lvds.c | 104 ++++++++++++++++++++++++----
> >  drivers/gpu/drm/rcar-du/rcar_lvds.h |   5 ++
> >  2 files changed, 96 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > index a331f0c32187..f7e4710fe33f 100644
> > --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > @@ -66,6 +66,9 @@ struct rcar_lvds {
> >
> >  	struct drm_display_mode display_mode;
> >  	enum rcar_lvds_mode mode;
> > +
> > +	struct drm_bridge *companion;
> > +	bool dual_link;
> >  };
> >
> >  #define bridge_to_rcar_lvds(bridge) \
> > @@ -400,11 +403,6 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
> >  {
> >  	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
> >  	const struct drm_display_mode *mode = &lvds->display_mode;
> > -	/*
> > -	 * FIXME: We should really retrieve the CRTC through the state, but how
> > -	 * do we get a state pointer?
> > -	 */
> > -	struct drm_crtc *crtc = lvds->bridge.encoder->crtc;
> >  	u32 lvdhcr;
> >  	u32 lvdcr0;
> >  	int ret;
> > @@ -413,6 +411,10 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
> >  	if (ret < 0)
> >  		return;
> >
> > +	/* Enable the companion LVDS encoder in dual-link mode. */
> > +	if (lvds->dual_link && lvds->companion)
> > +		lvds->companion->funcs->enable(lvds->companion);
> > +
> >  	/*
> >  	 * Hardcode the channels and control signals routing for now.
> >  	 *
> > @@ -435,17 +437,33 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
> >  	rcar_lvds_write(lvds, LVDCHCR, lvdhcr);
> >
> >  	if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK) {
> > -		/* Disable dual-link mode. */
> > -		rcar_lvds_write(lvds, LVDSTRIPE, 0);
> > +		/*
> > +		 * Configure vertical stripe based on the mode of operation of
> > +		 * the connected device.
> > +		 */
> > +		rcar_lvds_write(lvds, LVDSTRIPE,
> > +				lvds->dual_link ? LVDSTRIPE_ST_ON : 0);
> >  	}
> >
> > -	/* PLL clock configuration. */
> > -	lvds->info->pll_setup(lvds, mode->clock * 1000);
> > +	/*
> > +	 * PLL clock configuration on all instances but the companion in
> > +	 * dual-link mode.
> > +	 */
> > +	if (!lvds->dual_link || lvds->companion)
> > +		lvds->info->pll_setup(lvds, mode->clock * 1000);
> >
> >  	/* Set the LVDS mode and select the input. */
> >  	lvdcr0 = lvds->mode << LVDCR0_LVMD_SHIFT;
> > -	if (drm_crtc_index(crtc) == 2)
> > -		lvdcr0 |= LVDCR0_DUSEL;
> > +
> > +	if (lvds->bridge.encoder) {
> > +		/*
> > +		 * FIXME: We should really retrieve the CRTC through the state,
> > +		 * but how do we get a state pointer?
> > +		 */
> > +		if (drm_crtc_index(lvds->bridge.encoder->crtc) == 2)
> > +			lvdcr0 |= LVDCR0_DUSEL;
> > +	}
> > +
> >  	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
> >
> >  	/* Turn all the channels on. */
> > @@ -512,6 +530,10 @@ static void rcar_lvds_disable(struct drm_bridge *bridge)
> >  	rcar_lvds_write(lvds, LVDCR1, 0);
> >  	rcar_lvds_write(lvds, LVDPLLCR, 0);
> >
> > +	/* Disable the companion LVDS encoder in dual-link mode. */
> > +	if (lvds->dual_link && lvds->companion)
> > +		lvds->companion->funcs->disable(lvds->companion);
> > +
> >  	clk_disable_unprepare(lvds->clocks.mod);
> >  }
> >
> > @@ -628,10 +650,54 @@ static const struct drm_bridge_funcs rcar_lvds_bridge_ops = {
> >  	.mode_set = rcar_lvds_mode_set,
> >  };
> >
> > +bool rcar_lvds_dual_link(struct drm_bridge *bridge)
> > +{
> > +	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
> > +
> > +	return lvds->dual_link;
> > +}
> > +EXPORT_SYMBOL_GPL(rcar_lvds_dual_link);
> > +
> >  /* -----------------------------------------------------------------------------
> >   * Probe & Remove
> >   */
> >
> > +static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
> > +{
> > +	const struct of_device_id *match;
> > +	struct device_node *companion;
> > +	struct device *dev = lvds->dev;
> > +	int ret = 0;
> > +
> > +	/* Locate the companion LVDS encoder for dual-link operation, if any. */
> > +	companion = of_parse_phandle(dev->of_node, "renesas,companion", 0);
> > +	if (!companion)
> > +		return -ENODEV;
> > +
> > +	/*
> > +	 * Sanity check: the companion encoder must have the same compatible
> > +	 * string.
> > +	 */
> > +	match = of_match_device(dev->driver->of_match_table, dev);
> > +	if (!of_device_is_compatible(companion, match->compatible)) {
> > +		ret = -ENODEV;
> > +		goto done;
> > +	}
> > +
> > +	lvds->companion = of_drm_find_bridge(companion);
> > +	if (!lvds->companion) {
> > +		ret = -EPROBE_DEFER;
> > +		goto done;
> > +	}
> > +
> > +	dev_dbg(dev, "Found companion encoder %pOF\n", companion);
> > +
> > +done:
> > +	of_node_put(companion);
> > +
> > +	return ret;
> > +}
> > +
> >  static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
> >  {
> >  	struct device_node *local_output = NULL;
> > @@ -682,14 +748,26 @@ static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
> >
> >  	if (is_bridge) {
> >  		lvds->next_bridge = of_drm_find_bridge(remote);
> > -		if (!lvds->next_bridge)
> > +		if (!lvds->next_bridge) {
> >  			ret = -EPROBE_DEFER;
> > +			goto done;
> > +		}
> > +
> > +		if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK)
> > +			lvds->dual_link = lvds->next_bridge->timings
> > +					? lvds->next_bridge->timings->dual_link
> > +					: false;
> >  	} else {
> >  		lvds->panel = of_drm_find_panel(remote);
> > -		if (IS_ERR(lvds->panel))
> > +		if (IS_ERR(lvds->panel)) {
> >  			ret = PTR_ERR(lvds->panel);
> > +			goto done;
> > +		}
> >  	}
> >
> > +	if (lvds->dual_link)
> > +		ret = rcar_lvds_parse_dt_companion(lvds);
> 
> Looking at the error path here below, for E3/D3, -ENODEV gets
> sanitized to return 0 as we want this method to return success even if
> no endpoint is there, when using the LVDS encoder provided clock to
> back-feed the DU.
> 
> This is not the case for the companion property imho. If the property is
> specified, it should be sane and -ENODEV is worth being propagated to
> the caller.

But in that case the LVDS encoder will fail to probe, and so the DU
channel will not be able to output on the DPAD. Isn't it worth
supporting that ? Otherwise I can simply make
rcar_lvds_parse_dt_companion() return -EINVAL or -ENXIO and it should be
fine with the existing error handling path.

> You could move the error handling bits in the error path:
> 
> 	/*
> 	 * On D3/E3 the LVDS encoder provides a clock to the DU, which can be
> 	 * used for the DPAD output even when the LVDS output is not connected.
> 	 * Don't fail probe in that case as the DU will need the bridge to
> 	 * control the clock.
> 	 */
> 	if (lvds->info->quirks & RCAR_LVDS_QUIRK_EXT_PLL)
> 		return ret == -ENODEV ? 0 : ret;
> 
> before the of_node_put() sequences, and add one more label, to skip
> the above part in case parse_dt_companion() fails.
> 
> Apart from this you can retain my tag if you like.
> Thanks
>    j
> 
> > +
> >  done:
> >  	of_node_put(local_output);
> >  	of_node_put(remote_input);
> > diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.h b/drivers/gpu/drm/rcar-du/rcar_lvds.h
> > index a709cae1bc32..222ec0e60785 100644
> > --- a/drivers/gpu/drm/rcar-du/rcar_lvds.h
> > +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.h
> > @@ -15,6 +15,7 @@ struct drm_bridge;
> >  #if IS_ENABLED(CONFIG_DRM_RCAR_LVDS)
> >  int rcar_lvds_clk_enable(struct drm_bridge *bridge, unsigned long freq);
> >  void rcar_lvds_clk_disable(struct drm_bridge *bridge);
> > +bool rcar_lvds_dual_link(struct drm_bridge *bridge);
> >  #else
> >  static inline int rcar_lvds_clk_enable(struct drm_bridge *bridge,
> >  				       unsigned long freq)
> > @@ -22,6 +23,10 @@ static inline int rcar_lvds_clk_enable(struct drm_bridge *bridge,
> >  	return -ENOSYS;
> >  }
> >  static inline void rcar_lvds_clk_disable(struct drm_bridge *bridge) { }
> > +static inline bool rcar_lvds_dual_link(struct drm_bridge *bridge)
> > +{
> > +	return false;
> > +}
> >  #endif /* CONFIG_DRM_RCAR_LVDS */
> >
> >  #endif /* __RCAR_LVDS_H__ */

-- 
Regards,

Laurent Pinchart

^ permalink raw reply	[flat|nested] 25+ messages in thread

end of thread, back to index

Thread overview: 25+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-05-11 21:06 [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Laurent Pinchart
2019-05-11 21:06 ` [PATCH v2 01/10] drm: bridge: Add dual_link field to the drm_bridge_timings structure Laurent Pinchart
2019-05-11 21:06 ` [PATCH v2 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation Laurent Pinchart
2019-05-12  8:58   ` Geert Uytterhoeven
2019-05-12 10:22     ` Laurent Pinchart
2019-05-14 20:17   ` Rob Herring
2019-05-11 21:06 ` [PATCH v2 03/10] drm: bridge: thc63: Report input bus mode through bridge timings Laurent Pinchart
2019-05-28  9:05   ` Jacopo Mondi
2019-05-11 21:06 ` [PATCH v2 04/10] dt-bindings: display: renesas: lvds: Add renesas,companion property Laurent Pinchart
2019-05-28  9:28   ` Jacopo Mondi
2019-05-28 12:30     ` Laurent Pinchart
2019-05-11 21:06 ` [PATCH v2 05/10] drm: rcar-du: lvds: Remove LVDS double-enable checks Laurent Pinchart
2019-05-28  9:40   ` Jacopo Mondi
2019-05-11 21:06 ` [PATCH v2 06/10] drm: rcar-du: lvds: Add support for dual-link mode Laurent Pinchart
2019-05-28  9:35   ` Jacopo Mondi
2019-05-28 12:46     ` Laurent Pinchart
2019-05-11 21:06 ` [PATCH v2 07/10] drm: rcar-du: Skip LVDS1 output on Gen3 when using dual-link LVDS mode Laurent Pinchart
2019-05-28  9:38   ` Jacopo Mondi
2019-05-11 21:07 ` [PATCH v2 08/10] arm64: dts: renesas: r8a7799[05]: Point LVDS0 to its companion LVDS1 Laurent Pinchart
2019-05-28  9:39   ` Jacopo Mondi
2019-05-11 21:07 ` [PATCH v2 09/10] [HACK] arm64: dts: renesas: draak: Enable LVDS dual-link operation Laurent Pinchart
2019-05-11 21:07 ` [PATCH v2 10/10] [HACK] arm64: dts: renesas: ebisu: " Laurent Pinchart
2019-05-12  8:55 ` [PATCH v2 00/10] R-Car DU: LVDS dual-link mode support Geert Uytterhoeven
2019-05-12 10:15   ` Laurent Pinchart
2019-05-28 10:20 ` Jacopo Mondi

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