Subject: [PATCH] ARM: DTS: am33xx: Use the new DT bindings for the eDMA3

From: [email-masked] (Peter Ujfalusi)
Date: Tue, 8 Dec 2015 12:22:09 +0200

On 12/08/2015 11:51 AM, Arnd Bergmann wrote:
> On Tuesday 08 December 2015 09:42:26 Peter Ujfalusi wrote:
>> On 12/04/2015 11:51 PM, Tony Lindgren wrote:
>>>>
>>>> Please just drop the /bits/ 16 and use normal cells.
>>>
>>> Yeah agreed, makes things less confusing for sure 
>>
>> 4.4 will be the first kernel where we will have the new eDMA bindings. I have
>> chosen to use 16bit array for specifying the channels used for memcpy
>> (ti,edma-memcpy-channels) and for the reserving paRAM slots
>> (ti,edma-reserved-slot-ranges). As of now we have maximum of 64 channels and
>> 512 paRAM slots. 16bit is more than enough to store this information and it
>> even gives us enough room if ever in the future these numbers are going to
>> increase (which  they are not).
>>
>> But in order to change them to 32bit the driver needs to be changed as well.
>> Currently we do not have drivers (in 4.4) using the new bindings, 4.4 is not
>> yet out, so it might be possible to change the binding document and the driver
>> to use 32bit arrays. The driver internally uses 16bit type for these which I'm
>> not going to change, but the code parsing the DT needs to be adjusted for the
>> new data type.
>>
>> If Vinod is willing to take update for the DT binding of eDMA for 4.4-rc, I
>> can cook up the patch(es) to do so.
> 
> I hadn't realized that it was already in 4.4-rc. The change should be trivial
> enough though, so I'd still do it. If Vinod would rather not change it now,
> it's not overly important though.

But this change must be done before we have actual users of these properties,
which is the am33xx, am437x and the da850 conversion series I have sent recently.
We might want to have this changed for 4.4 since it is going to be an LTS
release...

-- 
P?ter