[RESEND PATCH v2 0/5] drm/tidss: Fixes data edge sampling on AM62X and AM62A

[RESEND PATCH v2 0/5] drm/tidss: Fixes data edge sampling on AM62X and AM62A

[Swamil Jain]

Currently the driver only configure the data edge sampling partially.
AM62X, AM62A and AM62P require it to be configured in two distinct
registers: one in tidss and one in the Control MMR registers.

Introduce a new dt property to link the proper syscon node from the main 
device registers into the tidss driver.

The series targets to fix the issue for AM62X and AM62A, later will add 
the changes required for AM62P after DSS support gets upstreamed.

Fixes: ad2ac9dc9426 ("drm/tidss: Add support for AM625 DSS")
Fixes: 5cc5ea7b6d7b ("drm/tidss: Add support for AM62A7 DSS")
---
Cc: stable@vger.kernel.org

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: Swamil Jain <s-jain1@ti.com>
---

Changelog v1->v2:
- Add all devices requiring the fix in cover letter
- Update Fixes tag
- Use "Cc: stable@vger.kernel.org" properly

Link to v1:
https://lore.kernel.org/all/20250730-fix-edge-handling-v1-0-1bdfb3fe7922@bootlin.com/
---

Louis Chauvet (4):
  dt-bindings: display: ti,am65x-dss: Add clk property for data edge
    synchronization
  dt-bindings: mfd: syscon: Add ti,am625-dss-clk-ctrl
  arm64: dts: ti: k3-am62-main: Add tidss clk-ctrl property
  drm/tidss: Fix sampling edge configuration

Swamil Jain (1):
  arm64: dts: ti: k3-am62a-main: Add tidss clk-ctrl property

 .../bindings/display/ti/ti,am65x-dss.yaml          |  6 ++++++
 Documentation/devicetree/bindings/mfd/syscon.yaml  |  3 ++-
 arch/arm64/boot/dts/ti/k3-am62-main.dtsi           |  6 ++++++
 arch/arm64/boot/dts/ti/k3-am62a-main.dtsi          |  7 +++++++
 drivers/gpu/drm/tidss/tidss_dispc.c                | 14 ++++++++++++++
 5 files changed, 35 insertions(+), 1 deletion(-)

[RESEND PATCH v2 1/5] dt-bindings: display: ti,am65x-dss: Add clk property for data edge synchronization

[Swamil Jain]

From: Louis Chauvet <louis.chauvet@bootlin.com>

The dt-bindings for the display, specifically ti,am65x-dss, need to
include a clock property for data edge synchronization. The current
implementation does not correctly apply the data edge sampling property.

To address this, synchronization of writes to two different registers is
required: one in the TIDSS IP (which is already described in the tidss
node) and one is in the Memory Mapped Control Register Modules.

As the Memory Mapped Control Register Modules is located in a different
IP, we need to use a phandle to write values in its registers.

Fixes: ad2ac9dc9426 ("drm/tidss: Add support for AM625 DSS")
Fixes: 5cc5ea7b6d7b ("drm/tidss: Add support for AM62A7 DSS")
Cc: stable@vger.kernel.org
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: Swamil Jain <s-jain1@ti.com>
---
 .../devicetree/bindings/display/ti/ti,am65x-dss.yaml        | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml b/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml
index 361e9cae6896..b9a373b56917 100644
--- a/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml
+++ b/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml
@@ -133,6 +133,12 @@ properties:
       and OLDI_CLK_IO_CTRL registers. This property is needed for OLDI
       interface to work.
 
+  ti,clk-ctrl:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      phandle to syscon device node mapping CFG0_CLK_CTRL registers.
+      This property is needed for proper data sampling edge.
+
   max-memory-bandwidth:
     $ref: /schemas/types.yaml#/definitions/uint32
     description:

Re: [RESEND PATCH v2 1/5] dt-bindings: display: ti,am65x-dss: Add clk property for data edge synchronization

[Krzysztof Kozlowski]

On Thu, Nov 06, 2025 at 07:42:23PM +0530, Swamil Jain wrote:
> From: Louis Chauvet <louis.chauvet@bootlin.com>
> 
> The dt-bindings for the display, specifically ti,am65x-dss, need to
> include a clock property for data edge synchronization. The current

clock properties are called "clocks". Please rephrase commit msg or use
proper clocks to indicate you access here a clock (if that's the case).

> implementation does not correctly apply the data edge sampling property.

Where is "data edge sampling property"? I do not see it in this binding.

> 
> To address this, synchronization of writes to two different registers is

How this binding achieves that "synchronization"? What are you even
describing here?

> required: one in the TIDSS IP (which is already described in the tidss
> node) and one is in the Memory Mapped Control Register Modules.
> 
> As the Memory Mapped Control Register Modules is located in a different

And now another therm - MMCR...

This commit msg is barely parseable - language is correct but it is a
mix of completely wrong terms.

In case you used LLM to write this - don't. Ever.

> IP, we need to use a phandle to write values in its registers.
> 
> Fixes: ad2ac9dc9426 ("drm/tidss: Add support for AM625 DSS")
> Fixes: 5cc5ea7b6d7b ("drm/tidss: Add support for AM62A7 DSS")

You still did not describe the actual bug being fixed here.

> Cc: stable@vger.kernel.org

Best regards,
Krzysztof

Re: [RESEND PATCH v2 1/5] dt-bindings: display: ti,am65x-dss: Add clk property for data edge synchronization

[Krzysztof Kozlowski]

On 07/11/2025 08:54, Krzysztof Kozlowski wrote:
> On Thu, Nov 06, 2025 at 07:42:23PM +0530, Swamil Jain wrote:
>> From: Louis Chauvet <louis.chauvet@bootlin.com>
>>
>> The dt-bindings for the display, specifically ti,am65x-dss, need to
>> include a clock property for data edge synchronization. The current
> 
> clock properties are called "clocks". Please rephrase commit msg or use
> proper clocks to indicate you access here a clock (if that's the case).
> 
>> implementation does not correctly apply the data edge sampling property.
> 
> Where is "data edge sampling property"? I do not see it in this binding.
> 
>>
>> To address this, synchronization of writes to two different registers is
> 
> How this binding achieves that "synchronization"? What are you even
> describing here?
> 
>> required: one in the TIDSS IP (which is already described in the tidss
>> node) and one is in the Memory Mapped Control Register Modules.
>>
>> As the Memory Mapped Control Register Modules is located in a different
> 
> And now another therm - MMCR...
> 
> This commit msg is barely parseable - language is correct but it is a
> mix of completely wrong terms.
> 
> In case you used LLM to write this - don't. Ever.
> 
>> IP, we need to use a phandle to write values in its registers.
>>
>> Fixes: ad2ac9dc9426 ("drm/tidss: Add support for AM625 DSS")
>> Fixes: 5cc5ea7b6d7b ("drm/tidss: Add support for AM62A7 DSS")
> 
> You still did not describe the actual bug being fixed here.
> 


Actually, NAK, because you ignored entire previous feedback!

Best regards,
Krzysztof

[RESEND PATCH v2 2/5] dt-bindings: mfd: syscon: Add ti,am625-dss-clk-ctrl

[Swamil Jain]

From: Louis Chauvet <louis.chauvet@bootlin.com>

The dt-bindings for the multi-function device (mfd) syscon need to include
ti,am625-dss-clk-ctrl. On AM62X, AM62A and AM62P devicess, the display
controller (tidss) has external registers to control certain clock
properties. These registers are located in the device configuration
registers, so they need to be declared using syscon. They will later be
used with a phandle in the tidss node.

Fixes: ad2ac9dc9426 ("drm/tidss: Add support for AM625 DSS")
Fixes: 5cc5ea7b6d7b ("drm/tidss: Add support for AM62A7 DSS")
Cc: stable@vger.kernel.org
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: Swamil Jain <s-jain1@ti.com>
---
 Documentation/devicetree/bindings/mfd/syscon.yaml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mfd/syscon.yaml b/Documentation/devicetree/bindings/mfd/syscon.yaml
index 657c38175fba..2dace701b9a6 100644
--- a/Documentation/devicetree/bindings/mfd/syscon.yaml
+++ b/Documentation/devicetree/bindings/mfd/syscon.yaml
@@ -123,6 +123,7 @@ select:
           - ti,am62-opp-efuse-table
           - ti,am62-usb-phy-ctrl
           - ti,am625-dss-oldi-io-ctrl
+          - ti,am625-dss-clk-ctrl
           - ti,am62p-cpsw-mac-efuse
           - ti,am654-dss-oldi-io-ctrl
           - ti,j784s4-acspcie-proxy-ctrl
@@ -232,6 +233,7 @@ properties:
           - ti,am62-opp-efuse-table
           - ti,am62-usb-phy-ctrl
           - ti,am625-dss-oldi-io-ctrl
+          - ti,am625-dss-clk-ctrl
           - ti,am62p-cpsw-mac-efuse
           - ti,am654-dss-oldi-io-ctrl
           - ti,j784s4-acspcie-proxy-ctrl
@@ -260,4 +262,3 @@ examples:
         compatible = "allwinner,sun8i-h3-system-controller", "syscon";
         reg = <0x01c00000 0x1000>;
     };
-...

Re: [RESEND PATCH v2 2/5] dt-bindings: mfd: syscon: Add ti,am625-dss-clk-ctrl

[Krzysztof Kozlowski]

On Thu, Nov 06, 2025 at 07:42:24PM +0530, Swamil Jain wrote:
> From: Louis Chauvet <louis.chauvet@bootlin.com>
> 
> The dt-bindings for the multi-function device (mfd) syscon need to include
> ti,am625-dss-clk-ctrl. On AM62X, AM62A and AM62P devicess, the display
> controller (tidss) has external registers to control certain clock
> properties. These registers are located in the device configuration
> registers, so they need to be declared using syscon. They will later be
> used with a phandle in the tidss node.
> 
> Fixes: ad2ac9dc9426 ("drm/tidss: Add support for AM625 DSS")
> Fixes: 5cc5ea7b6d7b ("drm/tidss: Add support for AM62A7 DSS")

Adding missing hardware is not a fix. Drop both.

> Cc: stable@vger.kernel.org

For sure not a stable commit. You just add new hardware.

> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> Signed-off-by: Swamil Jain <s-jain1@ti.com>
> ---
>  Documentation/devicetree/bindings/mfd/syscon.yaml | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

With these fixed/dropped:

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [RESEND PATCH v2 2/5] dt-bindings: mfd: syscon: Add ti,am625-dss-clk-ctrl

[Krzysztof Kozlowski]

On 07/11/2025 08:50, Krzysztof Kozlowski wrote:
> On Thu, Nov 06, 2025 at 07:42:24PM +0530, Swamil Jain wrote:
>> From: Louis Chauvet <louis.chauvet@bootlin.com>
>>
>> The dt-bindings for the multi-function device (mfd) syscon need to include
>> ti,am625-dss-clk-ctrl. On AM62X, AM62A and AM62P devicess, the display
>> controller (tidss) has external registers to control certain clock
>> properties. These registers are located in the device configuration
>> registers, so they need to be declared using syscon. They will later be
>> used with a phandle in the tidss node.
>>
>> Fixes: ad2ac9dc9426 ("drm/tidss: Add support for AM625 DSS")
>> Fixes: 5cc5ea7b6d7b ("drm/tidss: Add support for AM62A7 DSS")
> 
> Adding missing hardware is not a fix. Drop both.
> 
>> Cc: stable@vger.kernel.org
> 
> For sure not a stable commit. You just add new hardware.
> 
>> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
>> Signed-off-by: Swamil Jain <s-jain1@ti.com>
>> ---
>>  Documentation/devicetree/bindings/mfd/syscon.yaml | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> With these fixed/dropped:
> 
> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Un-acked, NAK.

You just ignored previous feedback.

Best regards,
Krzysztof

[RESEND PATCH v2 3/5] arm64: dts: ti: k3-am62-main: Add tidss clk-ctrl property

[Swamil Jain]

From: Louis Chauvet <louis.chauvet@bootlin.com>

For am62 processors, we need to use the newly created clk-ctrl property to
properly handle data edge sampling configuration. Add them in the main
device tree.

Fixes: ad2ac9dc9426 ("drm/tidss: Add support for AM625 DSS")
Cc: stable@vger.kernel.org
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: Swamil Jain <s-jain1@ti.com>
---
 arch/arm64/boot/dts/ti/k3-am62-main.dtsi | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-am62-main.dtsi b/arch/arm64/boot/dts/ti/k3-am62-main.dtsi
index a290a674767b..2b6c033ae393 100644
--- a/arch/arm64/boot/dts/ti/k3-am62-main.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am62-main.dtsi
@@ -77,6 +77,11 @@ audio_refclk1: clock-controller@82e4 {
 			#clock-cells = <0>;
 		};
 
+		dss_clk_ctrl: dss-clk-ctrl@8300 {
+			compatible = "ti,am625-dss-clk-ctrl", "syscon";
+			reg = <0x8300 0x4>;
+		};
+
 		dss_oldi_io_ctrl: oldi-io-controller@8600 {
 			compatible = "ti,am625-dss-oldi-io-ctrl", "syscon";
 			reg = <0x8600 0x200>;
@@ -801,6 +806,7 @@ dss: dss@30200000 {
 			 <&k3_clks 186 2>;
 		clock-names = "fck", "vp1", "vp2";
 		interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
+		ti,clk-ctrl = <&dss_clk_ctrl>;
 		status = "disabled";
 
 		oldi-transmitters {

Re: [RESEND PATCH v2 3/5] arm64: dts: ti: k3-am62-main: Add tidss clk-ctrl property

[Krzysztof Kozlowski]

On Thu, Nov 06, 2025 at 07:42:25PM +0530, Swamil Jain wrote:
> From: Louis Chauvet <louis.chauvet@bootlin.com>
> 
> For am62 processors, we need to use the newly created clk-ctrl property to
> properly handle data edge sampling configuration. Add them in the main
> device tree.
> 
> Fixes: ad2ac9dc9426 ("drm/tidss: Add support for AM625 DSS")
> Cc: stable@vger.kernel.org
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> Signed-off-by: Swamil Jain <s-jain1@ti.com>
> ---
>  arch/arm64/boot/dts/ti/k3-am62-main.dtsi | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/ti/k3-am62-main.dtsi b/arch/arm64/boot/dts/ti/k3-am62-main.dtsi
> index a290a674767b..2b6c033ae393 100644
> --- a/arch/arm64/boot/dts/ti/k3-am62-main.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-am62-main.dtsi
> @@ -77,6 +77,11 @@ audio_refclk1: clock-controller@82e4 {
>  			#clock-cells = <0>;
>  		};
>  
> +		dss_clk_ctrl: dss-clk-ctrl@8300 {
> +			compatible = "ti,am625-dss-clk-ctrl", "syscon";
> +			reg = <0x8300 0x4>;

Same problem as last time. Nothing improved.

NAK

Best regards,
Krzysztof

[RESEND PATCH v2 4/5] arm64: dts: ti: k3-am62a-main: Add tidss clk-ctrl property

[Swamil Jain]

For AM62A, we need to use the newly created clk-ctrl property to
properly handle data edge sampling configuration. Add them in main
device tree.

Fixes: 5cc5ea7b6d7b ("drm/tidss: Add support for AM62A7 DSS")
Cc: stable@vger.kernel.org
Signed-off-by: Swamil Jain <s-jain1@ti.com>
---
 arch/arm64/boot/dts/ti/k3-am62a-main.dtsi | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-am62a-main.dtsi b/arch/arm64/boot/dts/ti/k3-am62a-main.dtsi
index 9e5b75a4e88e..15a9ee35dbce 100644
--- a/arch/arm64/boot/dts/ti/k3-am62a-main.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am62a-main.dtsi
@@ -77,6 +77,12 @@ audio_refclk1: clock-controller@82e4 {
 			assigned-clock-parents = <&k3_clks 157 18>;
 			#clock-cells = <0>;
 		};
+
+		dss_clk_ctrl: dss-clk-ctrl@8300 {
+			compatible = "ti,am625-dss-clk-ctrl", "syscon";
+			reg = <0x8300 0x4>;
+		};
+
 	};
 
 	dmss: bus@48000000 {
@@ -1136,6 +1142,7 @@ dss: dss@30200000 {
 			 <&k3_clks 186 2>;
 		clock-names = "fck", "vp1", "vp2";
 		interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
+		ti,clk-ctrl = <&dss_clk_ctrl>;
 		status = "disabled";
 
 		dss_ports: ports {

Re: [RESEND PATCH v2 4/5] arm64: dts: ti: k3-am62a-main: Add tidss clk-ctrl property

[Krzysztof Kozlowski]

On Thu, Nov 06, 2025 at 07:42:26PM +0530, Swamil Jain wrote:
> For AM62A, we need to use the newly created clk-ctrl property to
> properly handle data edge sampling configuration. Add them in main
> device tree.
> 
> Fixes: 5cc5ea7b6d7b ("drm/tidss: Add support for AM62A7 DSS")
> Cc: stable@vger.kernel.org
> Signed-off-by: Swamil Jain <s-jain1@ti.com>
> ---
>  arch/arm64/boot/dts/ti/k3-am62a-main.dtsi | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/ti/k3-am62a-main.dtsi b/arch/arm64/boot/dts/ti/k3-am62a-main.dtsi
> index 9e5b75a4e88e..15a9ee35dbce 100644
> --- a/arch/arm64/boot/dts/ti/k3-am62a-main.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-am62a-main.dtsi
> @@ -77,6 +77,12 @@ audio_refclk1: clock-controller@82e4 {
>  			assigned-clock-parents = <&k3_clks 157 18>;
>  			#clock-cells = <0>;
>  		};
> +
> +		dss_clk_ctrl: dss-clk-ctrl@8300 {
> +			compatible = "ti,am625-dss-clk-ctrl", "syscon";
> +			reg = <0x8300 0x4>;

NAK, you just ignored everything which was said.

Best regards,
Krzysztof

[RESEND PATCH v2 5/5] drm/tidss: Fix sampling edge configuration

[Swamil Jain]

From: Louis Chauvet <louis.chauvet@bootlin.com>

As stated in the AM62x Technical Reference Manual (SPRUIV7B)[1], the data
sampling edge needs to be configured in two distinct registers: one in the
TIDSS IP and another in the memory-mapped control register modules. Since
the latter is not within the same address range, a phandle to a syscon
device is used to access the regmap.

Configure the CTRL_MMR register, as mentioned in the Technical Reference
Manual to fix sampling edge.

[1]: https://www.ti.com/lit/ug/spruiv7b/spruiv7b.pdf

Fixes: ad2ac9dc9426 ("drm/tidss: Add support for AM625 DSS")
Fixes: 5cc5ea7b6d7b ("drm/tidss: Add support for AM62A7 DSS")
Cc: stable@vger.kernel.org
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: Swamil Jain <s-jain1@ti.com>
---
 drivers/gpu/drm/tidss/tidss_dispc.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c b/drivers/gpu/drm/tidss/tidss_dispc.c
index d8e1a1bcd660..d09eecb72dc0 100644
--- a/drivers/gpu/drm/tidss/tidss_dispc.c
+++ b/drivers/gpu/drm/tidss/tidss_dispc.c
@@ -500,6 +500,7 @@ struct dispc_device {
 	const struct dispc_features *feat;
 
 	struct clk *fclk;
+	struct regmap *clk_ctrl;
 
 	bool is_enabled;
 
@@ -1234,6 +1235,11 @@ void dispc_vp_prepare(struct dispc_device *dispc, u32 hw_videoport,
 				  mode->crtc_hdisplay - 1) |
 		       FIELD_PREP(DISPC_VP_SIZE_SCREEN_VDISPLAY_MASK,
 				  mode->crtc_vdisplay - 1));
+
+	if (dispc->clk_ctrl) {
+		regmap_update_bits(dispc->clk_ctrl, 0, 0x100, ipc ? 0x100 : 0x000);
+		regmap_update_bits(dispc->clk_ctrl, 0, 0x200, rf ? 0x200 : 0x000);
+	}
 }
 
 void dispc_vp_enable(struct dispc_device *dispc, u32 hw_videoport)
@@ -3003,6 +3009,14 @@ int dispc_init(struct tidss_device *tidss)
 
 	dispc_init_errata(dispc);
 
+	dispc->clk_ctrl = syscon_regmap_lookup_by_phandle_optional(tidss->dev->of_node,
+								   "ti,clk-ctrl");
+	if (IS_ERR(dispc->clk_ctrl)) {
+		r = dev_err_probe(dispc->dev, PTR_ERR(dispc->clk_ctrl),
+				  "DISPC: syscon_regmap_lookup_by_phandle failed.\n");
+		return r;
+	}
+
 	dispc->fourccs = devm_kcalloc(dev, ARRAY_SIZE(dispc_color_formats),
 				      sizeof(*dispc->fourccs), GFP_KERNEL);
 	if (!dispc->fourccs)

Re: [RESEND PATCH v2 5/5] drm/tidss: Fix sampling edge configuration

[Krzysztof Kozlowski]

On Thu, Nov 06, 2025 at 07:42:27PM +0530, Swamil Jain wrote:
>  
>  void dispc_vp_enable(struct dispc_device *dispc, u32 hw_videoport)
> @@ -3003,6 +3009,14 @@ int dispc_init(struct tidss_device *tidss)
>  
>  	dispc_init_errata(dispc);
>  
> +	dispc->clk_ctrl = syscon_regmap_lookup_by_phandle_optional(tidss->dev->of_node,
> +								   "ti,clk-ctrl");
> +	if (IS_ERR(dispc->clk_ctrl)) {
> +		r = dev_err_probe(dispc->dev, PTR_ERR(dispc->clk_ctrl),
> +				  "DISPC: syscon_regmap_lookup_by_phandle failed.\n");
> +		return r;

NAK. Read previous comments instead of silently ignoring them.

Best regards,
Krzysztof