[PATCH] ARM : i.MX27 : split code for allocation of ressources of camera and eMMA

[Gaëtan Carlier]

On 09/05/2012 10:22 AM, javier Martin wrote:
> On 5 September 2012 09:37, Gaëtan Carlier <gcembed at gmail.com> wrote:
>> Hi Javier,
>> This is because I will send a patch to add support of eMMA-PP. eMMA-PrP is
>> not only used for soc-camera. It can also be used as stand-alone driver and
>> now to be able to use eMMA-PrP module, IMX_HAVE_PLATFORM_MX2_CAMERA must be
>> set.
>
> Do you mean the following stand-alone driver I submitted some time
> ago? Are you working on some improvements to it?
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/media/video/mx2_emmaprp.c;h=5f8a6f5b98f91c3af4e1bdbd06654e7b496d8d65;hb=HEAD
yes
>
> This driver can be used without applying your patch. Please take a
> look at the following patch which is pending to get merged in
> linux-media tree:
> https://patchwork.kernel.org/patch/1347921/
>
>
>> And if I follow this logic, I have to put declaration of eMMA-PP with imx-fb
>> and eMMA-PP can only be enabled if IMX_HAVE_PLATFORM_IMX_FB.
>> Of course, eMMA-PrP is almost always used with soc-camera and eMMA-PP with
>> LCDC (imx-fb) but eMMA can be used to do HW accelarated colorspace
>> conversion.
>
> Agree, there is already one driver supporting this feature.
>
>> It is not a problem for me to keep eMMA-PrP and mx2-camera together. It was
>> just to have a more independant eMMA driver.
>
> I won't oppose to it, for me it is just aesthetic. However, you must
> do it properly without breaking existing boards such as Visstrim_M10.
Ok, I missed your patch in mailing-list and I work with linux-next 
(20120824) so I didn't know that my patch would break yours. Sorry.
>
>> For the Visstrim_M10 board, I don't think that it is needed to set
>> IMX_HAVE_PLATFORM_MX2_EMMA because there is no reference to m2m-emmaprp and
>> mx2-camera embeds handling of eMMA-PrP without using eMMA-PrP driver.
>
> The following patch was sent to the list in Agust the 20th and will be
> merged in the linux-media tree. This patch does reference m2m-emmaprp
> in Visstrim_M10
> https://patchwork.kernel.org/patch/1347921/
>
> So, please, since you have to fix the wrong chunk and have to send a
> v2 anyways I strongly encourage you to add the flag
> IMX_HAVE_PLATFORM_MX2_EMMA to Visstrim_M10. This way nothing will be
> broken no matter your patch gets merged after or before mine.
What do you mean by "wrong chunk" ?
>
>> It seems that eMMA-PrP embeded in mx2camera handles more case than
>> stand-alone eMMA-PrP driver. Maybe eMMA-PrP driver needs some review to
>> handle all In/Out image formats ?
>
> eMMa-PrP is currently used in two drivers:
>
> 1. http://git.linuxtv.org/media_tree.git/blob/refs/heads/staging/for_v3.7:/drivers/media/platform/soc_camera/mx2_camera.c
> Where it is used as a substitute to a DMA that moves data between the
> CSI and RAM apart from providing more features like format conversion,
> etc... This is a soc_camera video capture driver.
>
> 2. http://git.linuxtv.org/media_tree.git/blob/refs/heads/staging/for_v3.7:/drivers/media/platform/mx2_emmaprp.c
> This is a stand-alone mem2mem v4l2 driver that can get YUYV 422 in the
> input and transform it to YUV 420. Of course, the driver can be
> extended to support more kinds of conversions.
>
> Regards.
>
Regards,
Gaëtan.