[PATCH 1/5] media: atmel-isi: correct yuv swap according to different sensor outputs

[g.liakhovetski@gmx.de (Guennadi Liakhovetski)]

Hi Josh,

On Tue, 22 Sep 2015, Josh Wu wrote:

> we need to configure the YCC_SWAP bits in ISI_CFG2 according to current
> sensor output and Atmel ISI output format.
> 
> Current there are two cases Atmel ISI supported:
>   1. Atmel ISI outputs YUYV format.
>      This case we need to setup YCC_SWAP according to sensor output
>      format.
>   2. Atmel ISI output a pass-through formats, which means no swap.
>      Just setup YCC_SWAP as default with no swap.
> 
> Signed-off-by: Josh Wu <josh.wu@atmel.com>
> ---
> 
>  drivers/media/platform/soc_camera/atmel-isi.c | 43 ++++++++++++++++++++-------
>  1 file changed, 33 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/media/platform/soc_camera/atmel-isi.c b/drivers/media/platform/soc_camera/atmel-isi.c
> index 45e304a..df64294 100644
> --- a/drivers/media/platform/soc_camera/atmel-isi.c
> +++ b/drivers/media/platform/soc_camera/atmel-isi.c
> @@ -103,13 +103,41 @@ static u32 isi_readl(struct atmel_isi *isi, u32 reg)
>  	return readl(isi->regs + reg);
>  }
>  
> +static u32 setup_cfg2_yuv_swap(struct atmel_isi *isi,
> +		const struct soc_camera_format_xlate *xlate)
> +{

This function will be called only for the four media codes from the 
switch-case statement below, namely for

MEDIA_BUS_FMT_VYUY8_2X8
MEDIA_BUS_FMT_UYVY8_2X8
MEDIA_BUS_FMT_YVYU8_2X8
MEDIA_BUS_FMT_YUYV8_2X8

> +	/* By default, no swap for the codec path of Atmel ISI. So codec
> +	* output is same as sensor's output.
> +	* For instance, if sensor's output is YUYV, then codec outputs YUYV.
> +	* And if sensor's output is UYVY, then codec outputs UYVY.
> +	*/
> +	u32 cfg2_yuv_swap = ISI_CFG2_YCC_SWAP_DEFAULT;

Then this ISI_CFG2_YCC_SWAP_DEFAULT will only hold for 
MEDIA_BUS_FMT_YUYV8_2X8? Why don't you just add one more case below? Don't 
think this initialisation is really justified.

> +
> +	if (xlate->host_fmt->fourcc == V4L2_PIX_FMT_YUYV) {
> +		/* all convert to YUYV */
> +		switch (xlate->code) {
> +		case MEDIA_BUS_FMT_VYUY8_2X8:
> +			cfg2_yuv_swap = ISI_CFG2_YCC_SWAP_MODE_3;
> +			break;
> +		case MEDIA_BUS_FMT_UYVY8_2X8:
> +			cfg2_yuv_swap = ISI_CFG2_YCC_SWAP_MODE_2;
> +			break;
> +		case MEDIA_BUS_FMT_YVYU8_2X8:
> +			cfg2_yuv_swap = ISI_CFG2_YCC_SWAP_MODE_1;
> +			break;
> +		}
> +	}
> +
> +	return cfg2_yuv_swap;
> +}
> +
>  static void configure_geometry(struct atmel_isi *isi, u32 width,
> -			u32 height, u32 code)
> +		u32 height, const struct soc_camera_format_xlate *xlate)
>  {
>  	u32 cfg2;
>  
>  	/* According to sensor's output format to set cfg2 */
> -	switch (code) {
> +	switch (xlate->code) {
>  	default:
>  	/* Grey */
>  	case MEDIA_BUS_FMT_Y8_1X8:
> @@ -117,16 +145,11 @@ static void configure_geometry(struct atmel_isi *isi, u32 width,
>  		break;
>  	/* YUV */
>  	case MEDIA_BUS_FMT_VYUY8_2X8:
> -		cfg2 = ISI_CFG2_YCC_SWAP_MODE_3 | ISI_CFG2_COL_SPACE_YCbCr;
> -		break;
>  	case MEDIA_BUS_FMT_UYVY8_2X8:
> -		cfg2 = ISI_CFG2_YCC_SWAP_MODE_2 | ISI_CFG2_COL_SPACE_YCbCr;
> -		break;
>  	case MEDIA_BUS_FMT_YVYU8_2X8:
> -		cfg2 = ISI_CFG2_YCC_SWAP_MODE_1 | ISI_CFG2_COL_SPACE_YCbCr;
> -		break;
>  	case MEDIA_BUS_FMT_YUYV8_2X8:
> -		cfg2 = ISI_CFG2_YCC_SWAP_DEFAULT | ISI_CFG2_COL_SPACE_YCbCr;
> +		cfg2 = ISI_CFG2_COL_SPACE_YCbCr |
> +				setup_cfg2_yuv_swap(isi, xlate);
>  		break;
>  	/* RGB, TODO */
>  	}

I would move this switch-case completely inside setup_cfg2_yuv_swap(). 
Just do

	cfg2 = setup_cfg2_yuv_swap(isi, xlate);

and handle the

 	case MEDIA_BUS_FMT_Y8_1X8:

in the function too. These two switch-case statements really look 
redundant.

> @@ -407,7 +430,7 @@ static int start_streaming(struct vb2_queue *vq, unsigned int count)
>  	isi_writel(isi, ISI_INTDIS, (u32)~0UL);
>  
>  	configure_geometry(isi, icd->user_width, icd->user_height,
> -				icd->current_fmt->code);
> +				icd->current_fmt);
>  
>  	spin_lock_irq(&isi->lock);
>  	/* Clear any pending interrupt */
> -- 
> 1.9.1
> 

Thanks
Guennadi