RE: AT91 ADC support

[Sergei Gavrikov <sergei.gavrikov@gmail.com>]

On Fri, 28 May 2010, Sergei Gavrikov wrote:

> On Thu, 27 May 2010, Christophe Coutand wrote:
>> Hi Sergei,
>> 
>> I have attached an updated var_io.h that includes ADC support for the
>> AT91M55800A. I took the opportunity to define the number of channels
>> per ADC in this file. It can be overwritten per platform basis since
>> AT91SAM7L64 for instance has 4 channels only.
>
> Hi Christophe,
>
> Thanks for your time. I will take a look this morning.

[snip]

>> The definition of AT91_MAX_ADC_CHAN must be removed from
>> devs/adc/arm/at91/current/src/adc_at91.c. I have not joined any patch
>> for it since I will hopefully submit a new driver that support both
>> ADCs.

Hi Christophe, John

Excuse, that took a bit more time for testing. So, with the latest sent
stuff, it's possible to build ADC driver and ADC tests for the next AT91
targets

   at91sam7sek: SUCCESS
   at91sam7xek: SUCCESS
   sam7ex256: SUCCESS
   eb55: SUCCESS
   phycore: SUCCESS

I'm personally do not see any pit stops which would block a check-in the
latest version of the driver. Christophe, thank you for your time and
contribution. John?

Sergei

>> -----Original Message-----
>> From: Sergei Gavrikov [mailto:sergei.gavrikov@gmail.com]
>> Sent: 27. mai 2010 18:38
>> To: Christophe Coutand
>> Cc: John Dallaway; eCos Patches
>> Subject: RE: AT91 ADC support
>> 
>> On Thu, 27 May 2010, Christophe Coutand wrote:
>>> Hi John,
>>> 
>>> It's pretty easy to add the required definition for the AT91M55800A
>>> targets. The only thing I see now is that this device contains 2 ADCs
>>> which I have not considered before. I guess there are several ways out
>>> of this:
>>> 
>>> 1- Update the actual AT91 ADC driver to make full use of the
>>> AT91M55800A targets. I guess should be done by loading a second ADC
>>> instance (one for each ADC. I have not been through all the thinking
>>> here...).
>>> 
>>> 2- or limit the AT91 driver to use only ADC0 of the AT91M55800A target
>>> for the time being.
>>> 
>>> 3- or exclude AT91M55800A targets for the time being.
>>> 
>>> IMO #1 is best but I cannot give any time frame for completing it.
>> 
>> Hi Christophe, John
>> 
>> I would prefer #1, if you want I can add that in AT91/ADC CDL/sources.
>> One thing: I won't be able to test it on real hardware (only build
>> process can be tested me).
>> 
>> John, what do you think: Can we add the second ADC instance without a
>> testing?
>> 
>>> One additional weakness of the driver is that it is made for up to 8
>>> channels. It is defined nowhere what the targeted CPU can actually
>>> handle, this is left to the user when configuring eCos. I believe this
>>> is pretty fine since the user must anyway know which signal he wants
>> to
>>> sample but you might disagree on that one.
>> 
>> I know only one target which would use all 8 channels :-) That's eCos
>> i386/Linux synthetic target.
>> 
>> Thanks for collaboration.
>> 
>> Sergei
>> 
>>> Regards,
>>> Christophe