[PATCH v4 0/7] drm/msm/mdp4: rework LVDS/LCDC panel support

[PATCH v4 0/7] drm/msm/mdp4: rework LVDS/LCDC panel support

[Dmitry Baryshkov]

The LCDC controller uses pixel clock provided by the multimedia clock
controller (mmcc) instead of using LVDS PHY clock directly. Link LVDS
clocks properly, taking MMCC into account.

MDP4 uses custom code to handle LVDS panel. It predates handling
EPROBE_DEFER, it tries to work when the panel device is not available,
etc. Switch MDP4 LCDC code to use drm_panel_bridge/drm_bridge_connector
to follow contemporary DRM practices.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
Changes in v4:
- Retained compatibility with older DT by reusing PLL as LCDC clock
  (Abhinav)
- Link to v3: https://lore.kernel.org/r/20250227-fd-mdp4-lvds-v3-0-c983788987ae@linaro.org

Changes in v3:
- Fixed commit message to explain that DT name is used in addition to
  the global system table lookup (Konrad).
- Link to v2: https://lore.kernel.org/r/20250220-fd-mdp4-lvds-v2-0-15afe5578a31@linaro.org

Changes in v2:
- Rebase on top of msm-next.
- Upgrade LVDS clock code to use clock providers and parent_data
- Use LVDS clock from the MMCC instead of using LVDS PHY directly
- Link to v1: https://lore.kernel.org/r/20220616090321.433249-1-dmitry.baryshkov@linaro.org

---
Dmitry Baryshkov (7):
      dt-bindings: display: msm: mdp4: add LCDC clock and PLL source
      drm/msm/mdp4: drop mpd4_lvds_pll_init stub
      drm/msm/mdp4: register the LVDS PLL as a clock provider
      drm/msm/mdp4: use parent_data for LVDS PLL
      drm/msm/mdp4: move move_valid callback to lcdc_encoder
      drm/msm/mdp4: switch LVDS to use drm_bridge/_connector
      arm: dts: qcom: apq8064: link LVDS clocks

 .../devicetree/bindings/display/msm/mdp4.yaml      |   9 +-
 arch/arm/boot/dts/qcom/qcom-apq8064.dtsi           |  16 ++-
 drivers/gpu/drm/msm/Makefile                       |   1 -
 drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c           |  34 ++++--
 drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h           |  16 +--
 drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c  |  50 ++++-----
 .../gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c    | 121 ---------------------
 drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c      |  51 ++++++---
 8 files changed, 105 insertions(+), 193 deletions(-)
---
base-commit: 52beceed7049f2b4dc65ed0cc84b673bf804b679
change-id: 20240317-fd-mdp4-lvds-e317f86fd99c

Best regards,
-- 
Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

[PATCH v4 1/7] dt-bindings: display: msm: mdp4: add LCDC clock and PLL source

[Dmitry Baryshkov]

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Add the LCDC / LVDS clock input and the XO used to drive internal LVDS
PLL to MDP4 controller bindings. The controller also provides LVDS PHY
PLL, so add optional #clock-cells to the device.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 Documentation/devicetree/bindings/display/msm/mdp4.yaml | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/display/msm/mdp4.yaml b/Documentation/devicetree/bindings/display/msm/mdp4.yaml
index 35204a2875795e2c1f7582c8fab227f8a9107ed9..03ee09faa335f332259b64a42eefa3ec199b8e03 100644
--- a/Documentation/devicetree/bindings/display/msm/mdp4.yaml
+++ b/Documentation/devicetree/bindings/display/msm/mdp4.yaml
@@ -18,9 +18,10 @@ properties:
 
   clocks:
     minItems: 6
-    maxItems: 6
+    maxItems: 8
 
   clock-names:
+    minItems: 6
     items:
       - const: core_clk
       - const: iface_clk
@@ -28,6 +29,12 @@ properties:
       - const: lut_clk
       - const: hdmi_clk
       - const: tv_clk
+      - const: lcdc_clk
+      - const: pxo
+        description: XO used to drive the internal LVDS PLL
+
+  '#clock-cells':
+    const: 0
 
   reg:
     maxItems: 1

-- 
2.39.5

[PATCH v4 2/7] drm/msm/mdp4: drop mpd4_lvds_pll_init stub

[Dmitry Baryshkov]

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Drop the !COMMON_CLK stub for mpd4_lvds_pll_init(), the DRM_MSM driver
depends on COMMON_CLK.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
---
 drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
index 94b1ba92785fe55f8ead3bb8a7f998dc24a76f6a..142ccb68b435263f91ba1ab27676e426d43e5d84 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
@@ -207,13 +207,6 @@ static inline struct drm_encoder *mdp4_dsi_encoder_init(struct drm_device *dev)
 }
 #endif
 
-#ifdef CONFIG_COMMON_CLK
 struct clk *mpd4_lvds_pll_init(struct drm_device *dev);
-#else
-static inline struct clk *mpd4_lvds_pll_init(struct drm_device *dev)
-{
-	return ERR_PTR(-ENODEV);
-}
-#endif
 
 #endif /* __MDP4_KMS_H__ */

-- 
2.39.5

[PATCH v4 3/7] drm/msm/mdp4: register the LVDS PLL as a clock provider

[Dmitry Baryshkov]

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

The LVDS/LCDC controller uses pixel clock coming from the multimedia
controller (mmcc) rather than using the PLL directly. Stop using LVDS
PLL directly and register it as a clock provider. Use lcdc_clk as a
pixel clock for the LCDC.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h          |  2 +-
 drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c |  3 +-
 drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c     | 45 ++++++++++++++++-------
 3 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
index 142ccb68b435263f91ba1ab27676e426d43e5d84..3d7ffd874e0d234f450f6170e623f87572456757 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
@@ -207,6 +207,6 @@ static inline struct drm_encoder *mdp4_dsi_encoder_init(struct drm_device *dev)
 }
 #endif
 
-struct clk *mpd4_lvds_pll_init(struct drm_device *dev);
+struct clk *mpd4_get_lcdc_clock(struct drm_device *dev);
 
 #endif /* __MDP4_KMS_H__ */
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c
index 8bbc7fb881d599e7d309cc61bda83697fecd253a..8694e5d7d3f012070c72214df063a6488b2ef707 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c
@@ -380,8 +380,7 @@ struct drm_encoder *mdp4_lcdc_encoder_init(struct drm_device *dev,
 
 	drm_encoder_helper_add(encoder, &mdp4_lcdc_encoder_helper_funcs);
 
-	/* TODO: do we need different pll in other cases? */
-	mdp4_lcdc_encoder->lcdc_clk = mpd4_lvds_pll_init(dev);
+	mdp4_lcdc_encoder->lcdc_clk = mpd4_get_lcdc_clock(dev);
 	if (IS_ERR(mdp4_lcdc_encoder->lcdc_clk)) {
 		DRM_DEV_ERROR(dev->dev, "failed to get lvds_clk\n");
 		return ERR_CAST(mdp4_lcdc_encoder->lcdc_clk);
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c
index ab8c0c187fb2cd05e26f5019244af15f1b2470c8..df2bbd475cc2a11da20ac07be8e757527ef41ae8 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c
@@ -133,29 +133,48 @@ static struct clk_init_data pll_init = {
 	.num_parents = ARRAY_SIZE(mpd4_lvds_pll_parents),
 };
 
-struct clk *mpd4_lvds_pll_init(struct drm_device *dev)
+static struct clk_hw *mpd4_lvds_pll_init(struct drm_device *dev)
 {
 	struct mdp4_lvds_pll *lvds_pll;
-	struct clk *clk;
 	int ret;
 
 	lvds_pll = devm_kzalloc(dev->dev, sizeof(*lvds_pll), GFP_KERNEL);
-	if (!lvds_pll) {
-		ret = -ENOMEM;
-		goto fail;
-	}
+	if (!lvds_pll)
+		return ERR_PTR(-ENOMEM);
 
 	lvds_pll->dev = dev;
 
 	lvds_pll->pll_hw.init = &pll_init;
-	clk = devm_clk_register(dev->dev, &lvds_pll->pll_hw);
-	if (IS_ERR(clk)) {
-		ret = PTR_ERR(clk);
-		goto fail;
+	ret = devm_clk_hw_register(dev->dev, &lvds_pll->pll_hw);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ret = devm_of_clk_add_hw_provider(dev->dev, of_clk_hw_simple_get, &lvds_pll->pll_hw);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return &lvds_pll->pll_hw;
+}
+
+struct clk *mpd4_get_lcdc_clock(struct drm_device *dev)
+{
+	struct clk_hw *hw;
+	struct clk *clk;
+
+
+	/* TODO: do we need different pll in other cases? */
+	hw = mpd4_lvds_pll_init(dev);
+	if (IS_ERR(hw)) {
+		DRM_DEV_ERROR(dev->dev, "failed to register LVDS PLL\n");
+		return ERR_CAST(hw);
 	}
 
-	return clk;
+	clk = devm_clk_get(dev->dev, "lcdc_clk");
+	if (clk == ERR_PTR(-ENOENT)) {
+		drm_warn(dev, "can't get LCDC clock, using PLL directly\n");
 
-fail:
-	return ERR_PTR(ret);
+		return devm_clk_hw_get_clk(dev->dev, hw, "lcdc_clk");
+	}
+
+	return clk;
 }

-- 
2.39.5

[PATCH v4 4/7] drm/msm/mdp4: use parent_data for LVDS PLL

[Dmitry Baryshkov]

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Instead of using .parent_names, use .parent_data, which binds parent
clocks by using relative names specified in DT in addition to using global
system clock names.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c
index df2bbd475cc2a11da20ac07be8e757527ef41ae8..fa2c294705105f5facbf7087a9d646f710c4a7fe 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c
@@ -122,14 +122,14 @@ static const struct clk_ops mpd4_lvds_pll_ops = {
 	.set_rate = mpd4_lvds_pll_set_rate,
 };
 
-static const char *mpd4_lvds_pll_parents[] = {
-	"pxo",
+static const struct clk_parent_data mpd4_lvds_pll_parents[] = {
+	{ .fw_name = "pxo", .name = "pxo", },
 };
 
 static struct clk_init_data pll_init = {
 	.name = "mpd4_lvds_pll",
 	.ops = &mpd4_lvds_pll_ops,
-	.parent_names = mpd4_lvds_pll_parents,
+	.parent_data = mpd4_lvds_pll_parents,
 	.num_parents = ARRAY_SIZE(mpd4_lvds_pll_parents),
 };
 

-- 
2.39.5

[PATCH v4 5/7] drm/msm/mdp4: move move_valid callback to lcdc_encoder

[Dmitry Baryshkov]

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

We can check the LCDC clock directly from the LCDC encoder driver, so
remove it from the LVDS connector.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
---
 drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h           |  1 -
 drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c  | 27 ++++++++++++++++------
 .../gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c    | 21 -----------------
 3 files changed, 20 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
index 3d7ffd874e0d234f450f6170e623f87572456757..66f5009fdf8aebcc543b5539d1c2d03075171001 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
@@ -191,7 +191,6 @@ struct drm_crtc *mdp4_crtc_init(struct drm_device *dev,
 long mdp4_dtv_round_pixclk(struct drm_encoder *encoder, unsigned long rate);
 struct drm_encoder *mdp4_dtv_encoder_init(struct drm_device *dev);
 
-long mdp4_lcdc_round_pixclk(struct drm_encoder *encoder, unsigned long rate);
 struct drm_encoder *mdp4_lcdc_encoder_init(struct drm_device *dev,
 		struct device_node *panel_node);
 
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c
index 8694e5d7d3f012070c72214df063a6488b2ef707..7f4e8005bc4ae0bc82ec5b87a1fea0530301b427 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c
@@ -348,19 +348,32 @@ static void mdp4_lcdc_encoder_enable(struct drm_encoder *encoder)
 	mdp4_lcdc_encoder->enabled = true;
 }
 
+static enum drm_mode_status
+mdp4_lcdc_encoder_mode_valid(struct drm_encoder *encoder,
+		const struct drm_display_mode *mode)
+{
+	struct mdp4_lcdc_encoder *mdp4_lcdc_encoder =
+			to_mdp4_lcdc_encoder(encoder);
+	long actual, requested;
+
+	requested = 1000 * mode->clock;
+	actual = clk_round_rate(mdp4_lcdc_encoder->lcdc_clk, requested);
+
+	DBG("requested=%ld, actual=%ld", requested, actual);
+
+	if (actual != requested)
+		return MODE_CLOCK_RANGE;
+
+	return MODE_OK;
+}
+
 static const struct drm_encoder_helper_funcs mdp4_lcdc_encoder_helper_funcs = {
 	.mode_set = mdp4_lcdc_encoder_mode_set,
 	.disable = mdp4_lcdc_encoder_disable,
 	.enable = mdp4_lcdc_encoder_enable,
+	.mode_valid = mdp4_lcdc_encoder_mode_valid,
 };
 
-long mdp4_lcdc_round_pixclk(struct drm_encoder *encoder, unsigned long rate)
-{
-	struct mdp4_lcdc_encoder *mdp4_lcdc_encoder =
-			to_mdp4_lcdc_encoder(encoder);
-	return clk_round_rate(mdp4_lcdc_encoder->lcdc_clk, rate);
-}
-
 /* initialize encoder */
 struct drm_encoder *mdp4_lcdc_encoder_init(struct drm_device *dev,
 		struct device_node *panel_node)
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c
index 52e728181b523cc3380d7718b5956e7e2dbd4cad..4755eb13ef79f313d2be088145c8cd2e615226fe 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c
@@ -56,26 +56,6 @@ static int mdp4_lvds_connector_get_modes(struct drm_connector *connector)
 	return ret;
 }
 
-static enum drm_mode_status
-mdp4_lvds_connector_mode_valid(struct drm_connector *connector,
-			       const struct drm_display_mode *mode)
-{
-	struct mdp4_lvds_connector *mdp4_lvds_connector =
-			to_mdp4_lvds_connector(connector);
-	struct drm_encoder *encoder = mdp4_lvds_connector->encoder;
-	long actual, requested;
-
-	requested = 1000 * mode->clock;
-	actual = mdp4_lcdc_round_pixclk(encoder, requested);
-
-	DBG("requested=%ld, actual=%ld", requested, actual);
-
-	if (actual != requested)
-		return MODE_CLOCK_RANGE;
-
-	return MODE_OK;
-}
-
 static const struct drm_connector_funcs mdp4_lvds_connector_funcs = {
 	.detect = mdp4_lvds_connector_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
@@ -87,7 +67,6 @@ static const struct drm_connector_funcs mdp4_lvds_connector_funcs = {
 
 static const struct drm_connector_helper_funcs mdp4_lvds_connector_helper_funcs = {
 	.get_modes = mdp4_lvds_connector_get_modes,
-	.mode_valid = mdp4_lvds_connector_mode_valid,
 };
 
 /* initialize connector */

-- 
2.39.5

[PATCH v4 6/7] drm/msm/mdp4: switch LVDS to use drm_bridge/_connector

[Dmitry Baryshkov]

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

LVDS support in MDP4 driver makes use of drm_connector directly. However
LCDC encoder and LVDS connector are wrappers around drm_panel. Switch
them to use drm_panel_bridge/drm_bridge_connector. This allows using
standard interface for the drm_panel and also inserting additional
bridges between encoder and panel.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/gpu/drm/msm/Makefile                       |   1 -
 drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c           |  34 +++++--
 drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h           |   6 +-
 drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c  |  20 +----
 .../gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c    | 100 ---------------------
 5 files changed, 28 insertions(+), 133 deletions(-)

diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
index 5df20cbeafb8bf07c825a1fd72719d5a56c38613..7a2ada6e2d74a902879e4f12a78ed475e5209ec2 100644
--- a/drivers/gpu/drm/msm/Makefile
+++ b/drivers/gpu/drm/msm/Makefile
@@ -48,7 +48,6 @@ msm-display-$(CONFIG_DRM_MSM_MDP4) += \
 	disp/mdp4/mdp4_dsi_encoder.o \
 	disp/mdp4/mdp4_dtv_encoder.o \
 	disp/mdp4/mdp4_lcdc_encoder.o \
-	disp/mdp4/mdp4_lvds_connector.o \
 	disp/mdp4/mdp4_lvds_pll.o \
 	disp/mdp4/mdp4_irq.o \
 	disp/mdp4/mdp4_kms.o \
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
index 689e210660a5218ed1e2d116073723215af5a187..93c9411eb422bc67b7fedb5ffce4c330310b520f 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
@@ -6,6 +6,8 @@
 
 #include <linux/delay.h>
 
+#include <drm/drm_bridge.h>
+#include <drm/drm_bridge_connector.h>
 #include <drm/drm_vblank.h>
 
 #include "msm_drv.h"
@@ -189,7 +191,7 @@ static int mdp4_modeset_init_intf(struct mdp4_kms *mdp4_kms,
 	struct msm_drm_private *priv = dev->dev_private;
 	struct drm_encoder *encoder;
 	struct drm_connector *connector;
-	struct device_node *panel_node;
+	struct drm_bridge *next_bridge;
 	int dsi_id;
 	int ret;
 
@@ -199,27 +201,43 @@ static int mdp4_modeset_init_intf(struct mdp4_kms *mdp4_kms,
 		 * bail out early if there is no panel node (no need to
 		 * initialize LCDC encoder and LVDS connector)
 		 */
-		panel_node = of_graph_get_remote_node(dev->dev->of_node, 0, 0);
-		if (!panel_node)
-			return 0;
+		next_bridge = devm_drm_of_get_bridge(dev->dev, dev->dev->of_node, 0, 0);
+		if (IS_ERR(next_bridge)) {
+			ret = PTR_ERR(next_bridge);
+			if (ret == -ENODEV)
+				return 0;
+			return ret;
+		}
 
-		encoder = mdp4_lcdc_encoder_init(dev, panel_node);
+		encoder = mdp4_lcdc_encoder_init(dev);
 		if (IS_ERR(encoder)) {
 			DRM_DEV_ERROR(dev->dev, "failed to construct LCDC encoder\n");
-			of_node_put(panel_node);
 			return PTR_ERR(encoder);
 		}
 
 		/* LCDC can be hooked to DMA_P (TODO: Add DMA_S later?) */
 		encoder->possible_crtcs = 1 << DMA_P;
 
-		connector = mdp4_lvds_connector_init(dev, panel_node, encoder);
+		ret = drm_bridge_attach(encoder, next_bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+		if (ret) {
+			DRM_DEV_ERROR(dev->dev, "failed to attach LVDS panel/bridge: %d\n", ret);
+
+			return ret;
+		}
+
+		connector = drm_bridge_connector_init(dev, encoder);
 		if (IS_ERR(connector)) {
 			DRM_DEV_ERROR(dev->dev, "failed to initialize LVDS connector\n");
-			of_node_put(panel_node);
 			return PTR_ERR(connector);
 		}
 
+		ret = drm_connector_attach_encoder(connector, encoder);
+		if (ret) {
+			DRM_DEV_ERROR(dev->dev, "failed to attach LVDS connector: %d\n", ret);
+
+			return ret;
+		}
+
 		break;
 	case DRM_MODE_ENCODER_TMDS:
 		encoder = mdp4_dtv_encoder_init(dev);
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
index 66f5009fdf8aebcc543b5539d1c2d03075171001..f9d988076337cb6fb63af8e76be59b2eb34ab327 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
@@ -191,11 +191,7 @@ struct drm_crtc *mdp4_crtc_init(struct drm_device *dev,
 long mdp4_dtv_round_pixclk(struct drm_encoder *encoder, unsigned long rate);
 struct drm_encoder *mdp4_dtv_encoder_init(struct drm_device *dev);
 
-struct drm_encoder *mdp4_lcdc_encoder_init(struct drm_device *dev,
-		struct device_node *panel_node);
-
-struct drm_connector *mdp4_lvds_connector_init(struct drm_device *dev,
-		struct device_node *panel_node, struct drm_encoder *encoder);
+struct drm_encoder *mdp4_lcdc_encoder_init(struct drm_device *dev);
 
 #ifdef CONFIG_DRM_MSM_DSI
 struct drm_encoder *mdp4_dsi_encoder_init(struct drm_device *dev);
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c
index 7f4e8005bc4ae0bc82ec5b87a1fea0530301b427..06a307c1272d10e678501062a63559c5672ce999 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c
@@ -14,7 +14,6 @@
 
 struct mdp4_lcdc_encoder {
 	struct drm_encoder base;
-	struct device_node *panel_node;
 	struct drm_panel *panel;
 	struct clk *lcdc_clk;
 	unsigned long int pixclock;
@@ -262,19 +261,12 @@ static void mdp4_lcdc_encoder_disable(struct drm_encoder *encoder)
 	struct mdp4_lcdc_encoder *mdp4_lcdc_encoder =
 			to_mdp4_lcdc_encoder(encoder);
 	struct mdp4_kms *mdp4_kms = get_kms(encoder);
-	struct drm_panel *panel;
 
 	if (WARN_ON(!mdp4_lcdc_encoder->enabled))
 		return;
 
 	mdp4_write(mdp4_kms, REG_MDP4_LCDC_ENABLE, 0);
 
-	panel = of_drm_find_panel(mdp4_lcdc_encoder->panel_node);
-	if (!IS_ERR(panel)) {
-		drm_panel_disable(panel);
-		drm_panel_unprepare(panel);
-	}
-
 	/*
 	 * Wait for a vsync so we know the ENABLE=0 latched before
 	 * the (connector) source of the vsync's gets disabled,
@@ -300,7 +292,6 @@ static void mdp4_lcdc_encoder_enable(struct drm_encoder *encoder)
 			to_mdp4_lcdc_encoder(encoder);
 	unsigned long pc = mdp4_lcdc_encoder->pixclock;
 	struct mdp4_kms *mdp4_kms = get_kms(encoder);
-	struct drm_panel *panel;
 	uint32_t config;
 	int ret;
 
@@ -335,12 +326,6 @@ static void mdp4_lcdc_encoder_enable(struct drm_encoder *encoder)
 	if (ret)
 		DRM_DEV_ERROR(dev->dev, "failed to enable lcdc_clk: %d\n", ret);
 
-	panel = of_drm_find_panel(mdp4_lcdc_encoder->panel_node);
-	if (!IS_ERR(panel)) {
-		drm_panel_prepare(panel);
-		drm_panel_enable(panel);
-	}
-
 	setup_phy(encoder);
 
 	mdp4_write(mdp4_kms, REG_MDP4_LCDC_ENABLE, 1);
@@ -375,8 +360,7 @@ static const struct drm_encoder_helper_funcs mdp4_lcdc_encoder_helper_funcs = {
 };
 
 /* initialize encoder */
-struct drm_encoder *mdp4_lcdc_encoder_init(struct drm_device *dev,
-		struct device_node *panel_node)
+struct drm_encoder *mdp4_lcdc_encoder_init(struct drm_device *dev)
 {
 	struct drm_encoder *encoder;
 	struct mdp4_lcdc_encoder *mdp4_lcdc_encoder;
@@ -387,8 +371,6 @@ struct drm_encoder *mdp4_lcdc_encoder_init(struct drm_device *dev,
 	if (IS_ERR(mdp4_lcdc_encoder))
 		return ERR_CAST(mdp4_lcdc_encoder);
 
-	mdp4_lcdc_encoder->panel_node = panel_node;
-
 	encoder = &mdp4_lcdc_encoder->base;
 
 	drm_encoder_helper_add(encoder, &mdp4_lcdc_encoder_helper_funcs);
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c
deleted file mode 100644
index 4755eb13ef79f313d2be088145c8cd2e615226fe..0000000000000000000000000000000000000000
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c
+++ /dev/null
@@ -1,100 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Copyright (C) 2014 Red Hat
- * Author: Rob Clark <robdclark@gmail.com>
- * Author: Vinay Simha <vinaysimha@inforcecomputing.com>
- */
-
-#include "mdp4_kms.h"
-
-struct mdp4_lvds_connector {
-	struct drm_connector base;
-	struct drm_encoder *encoder;
-	struct device_node *panel_node;
-	struct drm_panel *panel;
-};
-#define to_mdp4_lvds_connector(x) container_of(x, struct mdp4_lvds_connector, base)
-
-static enum drm_connector_status mdp4_lvds_connector_detect(
-		struct drm_connector *connector, bool force)
-{
-	struct mdp4_lvds_connector *mdp4_lvds_connector =
-			to_mdp4_lvds_connector(connector);
-
-	if (!mdp4_lvds_connector->panel) {
-		mdp4_lvds_connector->panel =
-			of_drm_find_panel(mdp4_lvds_connector->panel_node);
-		if (IS_ERR(mdp4_lvds_connector->panel))
-			mdp4_lvds_connector->panel = NULL;
-	}
-
-	return mdp4_lvds_connector->panel ?
-			connector_status_connected :
-			connector_status_disconnected;
-}
-
-static void mdp4_lvds_connector_destroy(struct drm_connector *connector)
-{
-	struct mdp4_lvds_connector *mdp4_lvds_connector =
-			to_mdp4_lvds_connector(connector);
-
-	drm_connector_cleanup(connector);
-
-	kfree(mdp4_lvds_connector);
-}
-
-static int mdp4_lvds_connector_get_modes(struct drm_connector *connector)
-{
-	struct mdp4_lvds_connector *mdp4_lvds_connector =
-			to_mdp4_lvds_connector(connector);
-	struct drm_panel *panel = mdp4_lvds_connector->panel;
-	int ret = 0;
-
-	if (panel)
-		ret = drm_panel_get_modes(panel, connector);
-
-	return ret;
-}
-
-static const struct drm_connector_funcs mdp4_lvds_connector_funcs = {
-	.detect = mdp4_lvds_connector_detect,
-	.fill_modes = drm_helper_probe_single_connector_modes,
-	.destroy = mdp4_lvds_connector_destroy,
-	.reset = drm_atomic_helper_connector_reset,
-	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
-	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
-};
-
-static const struct drm_connector_helper_funcs mdp4_lvds_connector_helper_funcs = {
-	.get_modes = mdp4_lvds_connector_get_modes,
-};
-
-/* initialize connector */
-struct drm_connector *mdp4_lvds_connector_init(struct drm_device *dev,
-		struct device_node *panel_node, struct drm_encoder *encoder)
-{
-	struct drm_connector *connector = NULL;
-	struct mdp4_lvds_connector *mdp4_lvds_connector;
-
-	mdp4_lvds_connector = kzalloc(sizeof(*mdp4_lvds_connector), GFP_KERNEL);
-	if (!mdp4_lvds_connector)
-		return ERR_PTR(-ENOMEM);
-
-	mdp4_lvds_connector->encoder = encoder;
-	mdp4_lvds_connector->panel_node = panel_node;
-
-	connector = &mdp4_lvds_connector->base;
-
-	drm_connector_init(dev, connector, &mdp4_lvds_connector_funcs,
-			DRM_MODE_CONNECTOR_LVDS);
-	drm_connector_helper_add(connector, &mdp4_lvds_connector_helper_funcs);
-
-	connector->polled = 0;
-
-	connector->interlace_allowed = 0;
-	connector->doublescan_allowed = 0;
-
-	drm_connector_attach_encoder(connector, encoder);
-
-	return connector;
-}

-- 
2.39.5

[PATCH v4 7/7] arm: dts: qcom: apq8064: link LVDS clocks

[Dmitry Baryshkov]

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Link LVDS clocks to the from MDP4 to the MMCC and back from the MMCC
to the MDP4 display controller.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 arch/arm/boot/dts/qcom/qcom-apq8064.dtsi | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/arch/arm/boot/dts/qcom/qcom-apq8064.dtsi b/arch/arm/boot/dts/qcom/qcom-apq8064.dtsi
index 5f1a6b4b764492486df1a2610979f56c0a37b64a..b884900716464b6291869ff50825762a55099982 100644
--- a/arch/arm/boot/dts/qcom/qcom-apq8064.dtsi
+++ b/arch/arm/boot/dts/qcom/qcom-apq8064.dtsi
@@ -737,7 +737,8 @@ mmcc: clock-controller@4000000 {
 				 <&dsi0_phy 0>,
 				 <&dsi1_phy 1>,
 				 <&dsi1_phy 0>,
-				 <&hdmi_phy>;
+				 <&hdmi_phy>,
+				 <&mdp>;
 			clock-names = "pxo",
 				      "pll3",
 				      "pll8_vote",
@@ -745,7 +746,8 @@ mmcc: clock-controller@4000000 {
 				      "dsi1pllbyte",
 				      "dsi2pll",
 				      "dsi2pllbyte",
-				      "hdmipll";
+				      "hdmipll",
+				      "lvdspll";
 		};
 
 		l2cc: clock-controller@2011000 {
@@ -1404,13 +1406,19 @@ mdp: display-controller@5100000 {
 				 <&mmcc MDP_AXI_CLK>,
 				 <&mmcc MDP_LUT_CLK>,
 				 <&mmcc HDMI_TV_CLK>,
-				 <&mmcc MDP_TV_CLK>;
+				 <&mmcc MDP_TV_CLK>,
+				 <&mmcc LVDS_CLK>,
+				 <&rpmcc RPM_PXO_CLK>;
 			clock-names = "core_clk",
 				      "iface_clk",
 				      "bus_clk",
 				      "lut_clk",
 				      "hdmi_clk",
-				      "tv_clk";
+				      "tv_clk",
+				      "lcdc_clk",
+				      "pxo";
+
+			#clock-cells = <0>;
 
 			iommus = <&mdp_port0 0
 				  &mdp_port0 2

-- 
2.39.5

Re: [PATCH v4 3/7] drm/msm/mdp4: register the LVDS PLL as a clock provider

[Abhinav Kumar]

On 4/25/2025 2:51 AM, Dmitry Baryshkov wrote:
> From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> 
> The LVDS/LCDC controller uses pixel clock coming from the multimedia
> controller (mmcc) rather than using the PLL directly. Stop using LVDS
> PLL directly and register it as a clock provider. Use lcdc_clk as a
> pixel clock for the LCDC.
> 
> Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h          |  2 +-
>   drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c |  3 +-
>   drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_pll.c     | 45 ++++++++++++++++-------
>   3 files changed, 34 insertions(+), 16 deletions(-)
> 


Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>

Re: [PATCH v4 6/7] drm/msm/mdp4: switch LVDS to use drm_bridge/_connector

[Abhinav Kumar]

On 4/25/2025 2:51 AM, Dmitry Baryshkov wrote:
> From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> 
> LVDS support in MDP4 driver makes use of drm_connector directly. However
> LCDC encoder and LVDS connector are wrappers around drm_panel. Switch
> them to use drm_panel_bridge/drm_bridge_connector. This allows using
> standard interface for the drm_panel and also inserting additional
> bridges between encoder and panel.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
>   drivers/gpu/drm/msm/Makefile                       |   1 -
>   drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c           |  34 +++++--
>   drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h           |   6 +-
>   drivers/gpu/drm/msm/disp/mdp4/mdp4_lcdc_encoder.c  |  20 +----
>   .../gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c    | 100 ---------------------
>   5 files changed, 28 insertions(+), 133 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
> index 5df20cbeafb8bf07c825a1fd72719d5a56c38613..7a2ada6e2d74a902879e4f12a78ed475e5209ec2 100644
> --- a/drivers/gpu/drm/msm/Makefile
> +++ b/drivers/gpu/drm/msm/Makefile
> @@ -48,7 +48,6 @@ msm-display-$(CONFIG_DRM_MSM_MDP4) += \
>   	disp/mdp4/mdp4_dsi_encoder.o \
>   	disp/mdp4/mdp4_dtv_encoder.o \
>   	disp/mdp4/mdp4_lcdc_encoder.o \
> -	disp/mdp4/mdp4_lvds_connector.o \
>   	disp/mdp4/mdp4_lvds_pll.o \
>   	disp/mdp4/mdp4_irq.o \
>   	disp/mdp4/mdp4_kms.o \
> diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
> index 689e210660a5218ed1e2d116073723215af5a187..93c9411eb422bc67b7fedb5ffce4c330310b520f 100644
> --- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
> +++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
> @@ -6,6 +6,8 @@
>   
>   #include <linux/delay.h>
>   
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_bridge_connector.h>
>   #include <drm/drm_vblank.h>
>   
>   #include "msm_drv.h"
> @@ -189,7 +191,7 @@ static int mdp4_modeset_init_intf(struct mdp4_kms *mdp4_kms,
>   	struct msm_drm_private *priv = dev->dev_private;
>   	struct drm_encoder *encoder;
>   	struct drm_connector *connector;
> -	struct device_node *panel_node;
> +	struct drm_bridge *next_bridge;
>   	int dsi_id;
>   	int ret;
>   
> @@ -199,27 +201,43 @@ static int mdp4_modeset_init_intf(struct mdp4_kms *mdp4_kms,
>   		 * bail out early if there is no panel node (no need to
>   		 * initialize LCDC encoder and LVDS connector)
>   		 */
> -		panel_node = of_graph_get_remote_node(dev->dev->of_node, 0, 0);
> -		if (!panel_node)
> -			return 0;
> +		next_bridge = devm_drm_of_get_bridge(dev->dev, dev->dev->of_node, 0, 0);
> +		if (IS_ERR(next_bridge)) {
> +			ret = PTR_ERR(next_bridge);
> +			if (ret == -ENODEV)
> +				return 0;
> +			return ret;
> +		}

Alright, I think this will protect us against the fact that there is no 
panel in the DT currently like before, hence

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>

Re: [PATCH v4 0/7] drm/msm/mdp4: rework LVDS/LCDC panel support

[Dmitry Baryshkov]

On Fri, 25 Apr 2025 12:51:50 +0300, Dmitry Baryshkov wrote:
> The LCDC controller uses pixel clock provided by the multimedia clock
> controller (mmcc) instead of using LVDS PHY clock directly. Link LVDS
> clocks properly, taking MMCC into account.
> 
> MDP4 uses custom code to handle LVDS panel. It predates handling
> EPROBE_DEFER, it tries to work when the panel device is not available,
> etc. Switch MDP4 LCDC code to use drm_panel_bridge/drm_bridge_connector
> to follow contemporary DRM practices.
> 
> [...]

Applied, thanks!

[1/7] dt-bindings: display: msm: mdp4: add LCDC clock and PLL source
      https://gitlab.freedesktop.org/lumag/msm/-/commit/2f1d131147aa
[2/7] drm/msm/mdp4: drop mpd4_lvds_pll_init stub
      https://gitlab.freedesktop.org/lumag/msm/-/commit/f6720d64d8eb
[3/7] drm/msm/mdp4: register the LVDS PLL as a clock provider
      https://gitlab.freedesktop.org/lumag/msm/-/commit/9c2f63da6a70
[4/7] drm/msm/mdp4: use parent_data for LVDS PLL
      https://gitlab.freedesktop.org/lumag/msm/-/commit/b641bf534cf4
[5/7] drm/msm/mdp4: move move_valid callback to lcdc_encoder
      https://gitlab.freedesktop.org/lumag/msm/-/commit/f26b80359bc7
[6/7] drm/msm/mdp4: switch LVDS to use drm_bridge/_connector
      https://gitlab.freedesktop.org/lumag/msm/-/commit/9b565edc44b6

Best regards,
-- 
Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

Re: (subset) [PATCH v4 0/7] drm/msm/mdp4: rework LVDS/LCDC panel support

[Bjorn Andersson]

On Fri, 25 Apr 2025 12:51:50 +0300, Dmitry Baryshkov wrote:
> The LCDC controller uses pixel clock provided by the multimedia clock
> controller (mmcc) instead of using LVDS PHY clock directly. Link LVDS
> clocks properly, taking MMCC into account.
> 
> MDP4 uses custom code to handle LVDS panel. It predates handling
> EPROBE_DEFER, it tries to work when the panel device is not available,
> etc. Switch MDP4 LCDC code to use drm_panel_bridge/drm_bridge_connector
> to follow contemporary DRM practices.
> 
> [...]

Applied, thanks!

[7/7] arm: dts: qcom: apq8064: link LVDS clocks
      commit: d8dc4889afc92bd8757fcab607b734c684fce167

Best regards,
-- 
Bjorn Andersson <andersson@kernel.org>

Re: [PATCH v4 0/7] drm/msm/mdp4: rework LVDS/LCDC panel support

[Dmitry Baryshkov]

On Fri, 25 Apr 2025 12:51:50 +0300, Dmitry Baryshkov wrote:
> The LCDC controller uses pixel clock provided by the multimedia clock
> controller (mmcc) instead of using LVDS PHY clock directly. Link LVDS
> clocks properly, taking MMCC into account.
> 
> MDP4 uses custom code to handle LVDS panel. It predates handling
> EPROBE_DEFER, it tries to work when the panel device is not available,
> etc. Switch MDP4 LCDC code to use drm_panel_bridge/drm_bridge_connector
> to follow contemporary DRM practices.
> 
> [...]

Applied, thanks!

[1/7] dt-bindings: display: msm: mdp4: add LCDC clock and PLL source
      https://gitlab.freedesktop.org/lumag/msm/-/commit/2f1d131147aa
[2/7] drm/msm/mdp4: drop mpd4_lvds_pll_init stub
      https://gitlab.freedesktop.org/lumag/msm/-/commit/f6720d64d8eb
[3/7] drm/msm/mdp4: register the LVDS PLL as a clock provider
      https://gitlab.freedesktop.org/lumag/msm/-/commit/9c2f63da6a70
[4/7] drm/msm/mdp4: use parent_data for LVDS PLL
      https://gitlab.freedesktop.org/lumag/msm/-/commit/b641bf534cf4
[5/7] drm/msm/mdp4: move move_valid callback to lcdc_encoder
      https://gitlab.freedesktop.org/lumag/msm/-/commit/f26b80359bc7
[6/7] drm/msm/mdp4: switch LVDS to use drm_bridge/_connector
      https://gitlab.freedesktop.org/lumag/msm/-/commit/9b565edc44b6

Best regards,
-- 
Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>