diff mbox series

[v2,4/7] media: imx: imx-mipi-csis: Set PIXEL_MODE for YUV422

Message ID 20220218183421.583874-5-jacopo@jmondi.org (mailing list archive)
State New, archived
Headers show
Series media: imx: Destage imx7-mipi-csis | expand

Commit Message

Jacopo Mondi Feb. 18, 2022, 6:34 p.m. UTC
Bits 13 and 12 of the ISP_CONFIGn register configure the PIXEL_MODE
which specifies the sampling size, in pixel component units, on the
CSI-2 output data interface when data are transferred to memory.

The register description in the chip manual specifies that DUAL mode
should be used for YUV422 data.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Xavier Roumegue <xavier.roumegue@oss.nxp.com>
---
 drivers/media/platform/imx/imx-mipi-csis.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Comments

Laurent Pinchart Feb. 20, 2022, 8:24 a.m. UTC | #1
Hi Jacopo,

Thank you for the patch.

On Fri, Feb 18, 2022 at 07:34:18PM +0100, Jacopo Mondi wrote:
> Bits 13 and 12 of the ISP_CONFIGn register configure the PIXEL_MODE
> which specifies the sampling size, in pixel component units, on the
> CSI-2 output data interface when data are transferred to memory.
> 
> The register description in the chip manual specifies that DUAL mode
> should be used for YUV422 data.
>
> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> Signed-off-by: Xavier Roumegue <xavier.roumegue@oss.nxp.com>
> ---
>  drivers/media/platform/imx/imx-mipi-csis.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/imx/imx-mipi-csis.c b/drivers/media/platform/imx/imx-mipi-csis.c
> index 3e7efcf43a5f..86e7ea3713d9 100644
> --- a/drivers/media/platform/imx/imx-mipi-csis.c
> +++ b/drivers/media/platform/imx/imx-mipi-csis.c
> @@ -173,6 +173,7 @@
>  #define MIPI_CSIS_ISPCFG_PIXEL_MODE_SINGLE	(0 << 12)
>  #define MIPI_CSIS_ISPCFG_PIXEL_MODE_DUAL	(1 << 12)
>  #define MIPI_CSIS_ISPCFG_PIXEL_MODE_QUAD	(2 << 12)	/* i.MX8M[MNP] only */
> +#define MIPI_CSIS_ISPCFG_PIXEL_MASK		(3 << 12)
>  #define MIPI_CSIS_ISPCFG_ALIGN_32BIT		BIT(11)
>  #define MIPI_CSIS_ISPCFG_FMT(fmt)		((fmt) << 2)
>  #define MIPI_CSIS_ISPCFG_FMT_MASK		(0x3f << 2)
> @@ -506,7 +507,13 @@ static void __mipi_csis_set_format(struct csi_state *state)
>  
>  	/* Color format */
>  	val = mipi_csis_read(state, MIPI_CSIS_ISP_CONFIG_CH(0));
> -	val &= ~(MIPI_CSIS_ISPCFG_ALIGN_32BIT | MIPI_CSIS_ISPCFG_FMT_MASK);
> +	val &= ~(MIPI_CSIS_ISPCFG_ALIGN_32BIT | MIPI_CSIS_ISPCFG_FMT_MASK
> +		| MIPI_CSIS_ISPCFG_PIXEL_MASK);
> +

Let's add some more information here too:

	/*
	 * YUV 4:2:2 can be transferred with 8 or 16 bits per clock sample
	 * (referred to in the documentation as single and dual pixel modes
	 * respectively, although the 8-bit mode transfers half a pixel per
	 * clock sample and the 16-bit mode one pixel). While both mode work
	 * when the CSIS is connected to a receiver that supports either option,
	 * single pixel mode requires clock rates twice as high. As all SoCs
	 * that integrate the CSIS can operate in 16-bit bit mode, and some do
	 * not support 8-bit mode (this is the case of the i.MX8MP), use dual
	 * pixel mode unconditionally.
	 */

With this,

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +	/* TODO: Verify which other formats require DUAL (or QUAD) modes. */

I expect that at least RAW8 could benefit from dual mode too. While the
i.MX8MM reference manual states that dual mode can also be used for
RAW10 and RAW12, I think the CSI bridge has a 16-bit input bus, so this
may not be possible (I could be wrong).

> +	if (state->csis_fmt->data_type == MIPI_CSI2_DATA_TYPE_YUV422_8)
> +		val |= MIPI_CSIS_ISPCFG_PIXEL_MODE_DUAL;
> +
>  	val |= MIPI_CSIS_ISPCFG_FMT(state->csis_fmt->data_type);
>  	mipi_csis_write(state, MIPI_CSIS_ISP_CONFIG_CH(0), val);
>
diff mbox series

Patch

diff --git a/drivers/media/platform/imx/imx-mipi-csis.c b/drivers/media/platform/imx/imx-mipi-csis.c
index 3e7efcf43a5f..86e7ea3713d9 100644
--- a/drivers/media/platform/imx/imx-mipi-csis.c
+++ b/drivers/media/platform/imx/imx-mipi-csis.c
@@ -173,6 +173,7 @@ 
 #define MIPI_CSIS_ISPCFG_PIXEL_MODE_SINGLE	(0 << 12)
 #define MIPI_CSIS_ISPCFG_PIXEL_MODE_DUAL	(1 << 12)
 #define MIPI_CSIS_ISPCFG_PIXEL_MODE_QUAD	(2 << 12)	/* i.MX8M[MNP] only */
+#define MIPI_CSIS_ISPCFG_PIXEL_MASK		(3 << 12)
 #define MIPI_CSIS_ISPCFG_ALIGN_32BIT		BIT(11)
 #define MIPI_CSIS_ISPCFG_FMT(fmt)		((fmt) << 2)
 #define MIPI_CSIS_ISPCFG_FMT_MASK		(0x3f << 2)
@@ -506,7 +507,13 @@  static void __mipi_csis_set_format(struct csi_state *state)
 
 	/* Color format */
 	val = mipi_csis_read(state, MIPI_CSIS_ISP_CONFIG_CH(0));
-	val &= ~(MIPI_CSIS_ISPCFG_ALIGN_32BIT | MIPI_CSIS_ISPCFG_FMT_MASK);
+	val &= ~(MIPI_CSIS_ISPCFG_ALIGN_32BIT | MIPI_CSIS_ISPCFG_FMT_MASK
+		| MIPI_CSIS_ISPCFG_PIXEL_MASK);
+
+	/* TODO: Verify which other formats require DUAL (or QUAD) modes. */
+	if (state->csis_fmt->data_type == MIPI_CSI2_DATA_TYPE_YUV422_8)
+		val |= MIPI_CSIS_ISPCFG_PIXEL_MODE_DUAL;
+
 	val |= MIPI_CSIS_ISPCFG_FMT(state->csis_fmt->data_type);
 	mipi_csis_write(state, MIPI_CSIS_ISP_CONFIG_CH(0), val);