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

Jacopo Mondi
2022-01-17T08:29:18Z

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
>