[PATCH 0/2] media: v4l2-mediabus: add support for dual edge sampling

[PATCH 0/2] media: v4l2-mediabus: add support for dual edge sampling

[Michael Riesch]

Hi all,

Some devices (such as the Rockchip Video Input Processor (VIP) or the IT6801
HDMI receiver) support sampling of the parallel data at both edges of the
interface pixel clock in order to reduce the pixel clock by two.
This series adds support for this feature by using the pclk-sample device
tree property.

Looking forward to your comments!

Best regards,
Michael

Michael Riesch (2):
  dt-bindings: media: video-interfaces: add support for dual edge
    sampling
  media: v4l2-mediabus: add support for dual edge sampling

 .../bindings/media/video-interfaces.yaml      |  5 ++--
 drivers/media/v4l2-core/v4l2-fwnode.c         | 23 +++++++++++++++----
 include/media/v4l2-mediabus.h                 | 17 +++++++-------
 3 files changed, 31 insertions(+), 14 deletions(-)

-- 
2.30.2

[PATCH 1/2] dt-bindings: media: video-interfaces: add support for dual edge sampling

[Michael Riesch]

Some devices support sampling of the parallel data at both edges of the
interface pixel clock in order to reduce the pixel clock by two.
Use the pclk-sample property to reflect this feature in the device tree.

Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
---
 .../devicetree/bindings/media/video-interfaces.yaml          | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/media/video-interfaces.yaml b/Documentation/devicetree/bindings/media/video-interfaces.yaml
index 4391dce2caee..b7f77a255778 100644
--- a/Documentation/devicetree/bindings/media/video-interfaces.yaml
+++ b/Documentation/devicetree/bindings/media/video-interfaces.yaml
@@ -144,9 +144,10 @@ properties:
 
   pclk-sample:
     $ref: /schemas/types.yaml#/definitions/uint32
-    enum: [ 0, 1 ]
+    enum: [ 0, 1, 2 ]
     description:
-      Sample data on rising (1) or falling (0) edge of the pixel clock signal.
+      Sample data on falling (0), rising (1) or both (2) edges of the pixel
+      clock signal.
 
   sync-on-green-active:
     $ref: /schemas/types.yaml#/definitions/uint32
-- 
2.30.2

[PATCH 2/2] media: v4l2-mediabus: add support for dual edge sampling

[Michael Riesch]

Some devices support sampling of the parallel data at both edges of the
interface pixel clock in order to reduce the pixel clock by two.
Add a mediabus flag that represents this feature.

Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
---
 drivers/media/v4l2-core/v4l2-fwnode.c | 23 +++++++++++++++++++----
 include/media/v4l2-mediabus.h         | 17 +++++++++--------
 2 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 00457e1e93f6..70adf6549f5b 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -296,10 +296,25 @@ v4l2_fwnode_endpoint_parse_parallel_bus(struct fwnode_handle *fwnode,
 
 	if (!fwnode_property_read_u32(fwnode, "pclk-sample", &v)) {
 		flags &= ~(V4L2_MBUS_PCLK_SAMPLE_RISING |
-			   V4L2_MBUS_PCLK_SAMPLE_FALLING);
-		flags |= v ? V4L2_MBUS_PCLK_SAMPLE_RISING :
-			V4L2_MBUS_PCLK_SAMPLE_FALLING;
-		pr_debug("pclk-sample %s\n", v ? "high" : "low");
+			   V4L2_MBUS_PCLK_SAMPLE_FALLING |
+			   V4L2_MBUS_PCLK_SAMPLE_DUALEDGE);
+		switch (v) {
+		case 0:
+			flags |= V4L2_MBUS_PCLK_SAMPLE_FALLING;
+			pr_debug("pclk-sample low\n");
+			break;
+		case 1:
+			flags |= V4L2_MBUS_PCLK_SAMPLE_RISING;
+			pr_debug("pclk-sample high\n");
+			break;
+		case 2:
+			flags |= V4L2_MBUS_PCLK_SAMPLE_DUALEDGE;
+			pr_debug("pclk-sample dual edge\n");
+			break;
+		default:
+			pr_warn("invalid argument for pclk-sample");
+			break;
+		}
 	}
 
 	if (!fwnode_property_read_u32(fwnode, "data-active", &v)) {
diff --git a/include/media/v4l2-mediabus.h b/include/media/v4l2-mediabus.h
index 841e190aedd9..c98f956ef586 100644
--- a/include/media/v4l2-mediabus.h
+++ b/include/media/v4l2-mediabus.h
@@ -57,17 +57,18 @@
 #define V4L2_MBUS_VSYNC_ACTIVE_LOW		BIT(5)
 #define V4L2_MBUS_PCLK_SAMPLE_RISING		BIT(6)
 #define V4L2_MBUS_PCLK_SAMPLE_FALLING		BIT(7)
-#define V4L2_MBUS_DATA_ACTIVE_HIGH		BIT(8)
-#define V4L2_MBUS_DATA_ACTIVE_LOW		BIT(9)
+#define V4L2_MBUS_PCLK_SAMPLE_DUALEDGE		BIT(8)
+#define V4L2_MBUS_DATA_ACTIVE_HIGH		BIT(9)
+#define V4L2_MBUS_DATA_ACTIVE_LOW		BIT(10)
 /* FIELD = 0/1 - Field1 (odd)/Field2 (even) */
-#define V4L2_MBUS_FIELD_EVEN_HIGH		BIT(10)
+#define V4L2_MBUS_FIELD_EVEN_HIGH		BIT(11)
 /* FIELD = 1/0 - Field1 (odd)/Field2 (even) */
-#define V4L2_MBUS_FIELD_EVEN_LOW		BIT(11)
+#define V4L2_MBUS_FIELD_EVEN_LOW		BIT(12)
 /* Active state of Sync-on-green (SoG) signal, 0/1 for LOW/HIGH respectively. */
-#define V4L2_MBUS_VIDEO_SOG_ACTIVE_HIGH		BIT(12)
-#define V4L2_MBUS_VIDEO_SOG_ACTIVE_LOW		BIT(13)
-#define V4L2_MBUS_DATA_ENABLE_HIGH		BIT(14)
-#define V4L2_MBUS_DATA_ENABLE_LOW		BIT(15)
+#define V4L2_MBUS_VIDEO_SOG_ACTIVE_HIGH		BIT(13)
+#define V4L2_MBUS_VIDEO_SOG_ACTIVE_LOW		BIT(14)
+#define V4L2_MBUS_DATA_ENABLE_HIGH		BIT(15)
+#define V4L2_MBUS_DATA_ENABLE_LOW		BIT(16)
 
 /* Serial flags */
 /* CSI-2 D-PHY number of data lanes. */
-- 
2.30.2

Re: [PATCH 1/2] dt-bindings: media: video-interfaces: add support for dual edge sampling

[Jacopo Mondi]

Hi Michael,

On Fri, Jan 14, 2022 at 11:57:54AM +0100, Michael Riesch wrote:
> Some devices support sampling of the parallel data at both edges of the
> interface pixel clock in order to reduce the pixel clock by two.
> Use the pclk-sample property to reflect this feature in the device tree.
>
> Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>

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

Thanks
  j

> ---
>  .../devicetree/bindings/media/video-interfaces.yaml          | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/media/video-interfaces.yaml b/Documentation/devicetree/bindings/media/video-interfaces.yaml
> index 4391dce2caee..b7f77a255778 100644
> --- a/Documentation/devicetree/bindings/media/video-interfaces.yaml
> +++ b/Documentation/devicetree/bindings/media/video-interfaces.yaml
> @@ -144,9 +144,10 @@ properties:
>
>    pclk-sample:
>      $ref: /schemas/types.yaml#/definitions/uint32
> -    enum: [ 0, 1 ]
> +    enum: [ 0, 1, 2 ]
>      description:
> -      Sample data on rising (1) or falling (0) edge of the pixel clock signal.
> +      Sample data on falling (0), rising (1) or both (2) edges of the pixel
> +      clock signal.
>
>    sync-on-green-active:
>      $ref: /schemas/types.yaml#/definitions/uint32
> --
> 2.30.2
>

Re: [PATCH 2/2] media: v4l2-mediabus: add support for dual edge sampling

[Jacopo Mondi]

Hi Michael

On Fri, Jan 14, 2022 at 11:57:55AM +0100, Michael Riesch wrote:
> Some devices support sampling of the parallel data at both edges of the
> interface pixel clock in order to reduce the pixel clock by two.
> Add a mediabus flag that represents this feature.
>
> Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>

I was not expecting this :)
But I guess makes sense to add such option.

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

Thanks
  j

> ---
>  drivers/media/v4l2-core/v4l2-fwnode.c | 23 +++++++++++++++++++----
>  include/media/v4l2-mediabus.h         | 17 +++++++++--------
>  2 files changed, 28 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> index 00457e1e93f6..70adf6549f5b 100644
> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> @@ -296,10 +296,25 @@ v4l2_fwnode_endpoint_parse_parallel_bus(struct fwnode_handle *fwnode,
>
>  	if (!fwnode_property_read_u32(fwnode, "pclk-sample", &v)) {
>  		flags &= ~(V4L2_MBUS_PCLK_SAMPLE_RISING |
> -			   V4L2_MBUS_PCLK_SAMPLE_FALLING);
> -		flags |= v ? V4L2_MBUS_PCLK_SAMPLE_RISING :
> -			V4L2_MBUS_PCLK_SAMPLE_FALLING;
> -		pr_debug("pclk-sample %s\n", v ? "high" : "low");
> +			   V4L2_MBUS_PCLK_SAMPLE_FALLING |
> +			   V4L2_MBUS_PCLK_SAMPLE_DUALEDGE);
> +		switch (v) {
> +		case 0:
> +			flags |= V4L2_MBUS_PCLK_SAMPLE_FALLING;
> +			pr_debug("pclk-sample low\n");
> +			break;
> +		case 1:
> +			flags |= V4L2_MBUS_PCLK_SAMPLE_RISING;
> +			pr_debug("pclk-sample high\n");
> +			break;
> +		case 2:
> +			flags |= V4L2_MBUS_PCLK_SAMPLE_DUALEDGE;
> +			pr_debug("pclk-sample dual edge\n");
> +			break;
> +		default:
> +			pr_warn("invalid argument for pclk-sample");
> +			break;
> +		}
>  	}
>
>  	if (!fwnode_property_read_u32(fwnode, "data-active", &v)) {
> diff --git a/include/media/v4l2-mediabus.h b/include/media/v4l2-mediabus.h
> index 841e190aedd9..c98f956ef586 100644
> --- a/include/media/v4l2-mediabus.h
> +++ b/include/media/v4l2-mediabus.h
> @@ -57,17 +57,18 @@
>  #define V4L2_MBUS_VSYNC_ACTIVE_LOW		BIT(5)
>  #define V4L2_MBUS_PCLK_SAMPLE_RISING		BIT(6)
>  #define V4L2_MBUS_PCLK_SAMPLE_FALLING		BIT(7)
> -#define V4L2_MBUS_DATA_ACTIVE_HIGH		BIT(8)
> -#define V4L2_MBUS_DATA_ACTIVE_LOW		BIT(9)
> +#define V4L2_MBUS_PCLK_SAMPLE_DUALEDGE		BIT(8)
> +#define V4L2_MBUS_DATA_ACTIVE_HIGH		BIT(9)
> +#define V4L2_MBUS_DATA_ACTIVE_LOW		BIT(10)
>  /* FIELD = 0/1 - Field1 (odd)/Field2 (even) */
> -#define V4L2_MBUS_FIELD_EVEN_HIGH		BIT(10)
> +#define V4L2_MBUS_FIELD_EVEN_HIGH		BIT(11)
>  /* FIELD = 1/0 - Field1 (odd)/Field2 (even) */
> -#define V4L2_MBUS_FIELD_EVEN_LOW		BIT(11)
> +#define V4L2_MBUS_FIELD_EVEN_LOW		BIT(12)
>  /* Active state of Sync-on-green (SoG) signal, 0/1 for LOW/HIGH respectively. */
> -#define V4L2_MBUS_VIDEO_SOG_ACTIVE_HIGH		BIT(12)
> -#define V4L2_MBUS_VIDEO_SOG_ACTIVE_LOW		BIT(13)
> -#define V4L2_MBUS_DATA_ENABLE_HIGH		BIT(14)
> -#define V4L2_MBUS_DATA_ENABLE_LOW		BIT(15)
> +#define V4L2_MBUS_VIDEO_SOG_ACTIVE_HIGH		BIT(13)
> +#define V4L2_MBUS_VIDEO_SOG_ACTIVE_LOW		BIT(14)
> +#define V4L2_MBUS_DATA_ENABLE_HIGH		BIT(15)
> +#define V4L2_MBUS_DATA_ENABLE_LOW		BIT(16)
>
>  /* Serial flags */
>  /* CSI-2 D-PHY number of data lanes. */
> --
> 2.30.2
>

Re: [PATCH 1/2] dt-bindings: media: video-interfaces: add support for dual edge sampling

[Rob Herring]

On Fri, 14 Jan 2022 11:57:54 +0100, Michael Riesch wrote:
> Some devices support sampling of the parallel data at both edges of the
> interface pixel clock in order to reduce the pixel clock by two.
> Use the pclk-sample property to reflect this feature in the device tree.
> 
> Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
> ---
>  .../devicetree/bindings/media/video-interfaces.yaml          | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 

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