Re: Blockers on IIO usage of regmap.

From: Jonathan Cameron
Date: Wed Sep 07 2011 - 14:04:26 EST


On 09/07/11 18:57, Mark Brown wrote:
> On Wed, Sep 07, 2011 at 05:10:24PM +0100, Jonathan Cameron wrote:
>
> Please fix your mailer to word wrap at less than 80 colums, they're
> really quite hard to read as a result of this.
>
>> CS -_______________________-
>> TX Ada0...Ada7 Da0....Da7
>> RX XXXXXXXXXXXXXXXXXXXXXXXXX
>>
>> Reads are 16 bit with either of the two 8 bit register addresses given the same value
>>
>> CS -______________________-_____________________-
>> TX Ada0....Ada7 XXXXXXXX
>> RX XXXXXXXXXXXXXXXXXXXXX Da0...Da7 Db0....Db7
>
>> Can interpret Da0...Da7 and Db0....Db7 as single 16 bit register and consider this device
>> to just have a weird write method and normal read. Might be easier. I'll define Ax<n> as
>> 16 bit address for the burst read.
>
> This is starting to seem pretty far off the reservation.
Indeed.
>
>> Perhaps the burst mode thing is better handled by just providing a hook to allow data to be pushed
>> into regmap (from 'magic' sources), but the weird write read combination looks to me like something
>> that makes sense to have in regmap (be it as another bus variant).
>
> Probably not as a bus, it sounds like a marshalling difference rather
> than a bus - the buses should really only understand byte streams. I
> don't have any bright ideas on how to deal with this, it's fairly far
> away from the problem space I'm worried about.
The right answer maybe that it isn't a good idea to do it at all, but it
wasn't obvious until I tried! Having done it I'm not sure either way.

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