linux-kernel - Re: [PATCH 2/2] media: atmel-isi: move configure_geometry() to start

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Date:	Sun, 30 Aug 2015 11:26:06 +0200 (CEST)
From:	Guennadi Liakhovetski <g.liakhovetski@....de>
To:	Josh Wu <josh.wu@...el.com>
cc:	Linux Media Mailing List <linux-media@...r.kernel.org>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Mauro Carvalho Chehab <mchehab@....samsung.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] media: atmel-isi: move configure_geometry() to
 start_streaming()

Hi Josh,

On Wed, 17 Jun 2015, Josh Wu wrote:

> As in set_fmt() function we only need to know which format is been set,
> we don't need to access the ISI hardware in this moment.
> 
> So move the configure_geometry(), which access the ISI hardware, to
> start_streaming() will make code more consistent and simpler.
> 
> Signed-off-by: Josh Wu <josh.wu@...el.com>
> ---
> 
>  drivers/media/platform/soc_camera/atmel-isi.c | 17 +++++------------
>  1 file changed, 5 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/media/platform/soc_camera/atmel-isi.c b/drivers/media/platform/soc_camera/atmel-isi.c
> index 8bc40ca..b01086d 100644
> --- a/drivers/media/platform/soc_camera/atmel-isi.c
> +++ b/drivers/media/platform/soc_camera/atmel-isi.c
> @@ -390,6 +390,11 @@ static int start_streaming(struct vb2_queue *vq, unsigned int count)
>  	/* Disable all interrupts */
>  	isi_writel(isi, ISI_INTDIS, (u32)~0UL);
>  
> +	ret = configure_geometry(isi, icd->user_width, icd->user_height,
> +				icd->current_fmt->code);
> +	if (ret < 0)
> +		return ret;

No. Firstly, you'd have to pm_runtime_put() here if you fail. Secondly I 
think it's better to fail earlier - at S_FMT, than here. Not accessing the 
hardware in S_FMT is a good idea, but I'd at least do all the checking 
there. So, maybe add a "u32 cfg2_cr" field to struct atmel_isi, calculate 
it in S_FMT but only write to the hardware in start_streaming()?

Thanks
Guennadi

> +
>  	spin_lock_irq(&isi->lock);
>  	/* Clear any pending interrupt */
>  	isi_readl(isi, ISI_STATUS);
> @@ -477,8 +482,6 @@ static int isi_camera_init_videobuf(struct vb2_queue *q,
>  static int isi_camera_set_fmt(struct soc_camera_device *icd,
>  			      struct v4l2_format *f)
>  {
> -	struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
> -	struct atmel_isi *isi = ici->priv;
>  	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
>  	const struct soc_camera_format_xlate *xlate;
>  	struct v4l2_pix_format *pix = &f->fmt.pix;
> @@ -511,16 +514,6 @@ static int isi_camera_set_fmt(struct soc_camera_device *icd,
>  	if (mf->code != xlate->code)
>  		return -EINVAL;
>  
> -	/* Enable PM and peripheral clock before operate isi registers */
> -	pm_runtime_get_sync(ici->v4l2_dev.dev);
> -
> -	ret = configure_geometry(isi, pix->width, pix->height, xlate->code);
> -
> -	pm_runtime_put(ici->v4l2_dev.dev);
> -
> -	if (ret < 0)
> -		return ret;
> -
>  	pix->width		= mf->width;
>  	pix->height		= mf->height;
>  	pix->field		= mf->field;
> -- 
> 1.9.1
> 
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