DAC switch between current and voltage mode

DAC switch between current and voltage mode

[Sean Nyekjær]

Hi all

I'm in the process of creating a custom BSP with an ad5755 dac. It an requirement to be able to switch between voltage and current mode per channel from userspace.
Is it possible with the current iio interface?
Is there a feature in the pipeline where it's possible to do this switch?

Regards
Sean Nyekjær

Re: DAC switch between current and voltage mode

[Sean Nyekjær]

Hi Lars-Peter

Sorry the write again. Is the possible with the current iio interface to 
switch a dac from voltage to current mode from userspace?
If not, will upstream be interrested in a patch if it's possible?

Regards
Sean Nyekjær

On 2015-08-20 11:57, Sean Nyekjær wrote:
> Hi all
>
> I'm in the process of creating a custom BSP with an ad5755 dac. It an requirement to be able to switch between voltage and current mode per channel from userspace.
> Is it possible with the current iio interface?
> Is there a feature in the pipeline where it's possible to do this switch?
>
> Regards
> Sean Nyekjær--
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: DAC switch between current and voltage mode

[Lars-Peter Clausen]

On 08/24/2015 08:44 AM, Sean Nyekjær wrote:
> Hi Lars-Peter
> 
> Sorry the write again. Is the possible with the current iio interface to
> switch a dac from voltage to current mode from userspace?
> If not, will upstream be interrested in a patch if it's possible?

Hi,

Currently this does not work. A patch to add support for this is certainly
welcome. I'm just not sure what the interface for this should look like.
Maybe register both a current and a voltage channel and only allow one of
them to be powered at a time.

- Lars


> 
> Regards
> Sean Nyekjær
> 
> On 2015-08-20 11:57, Sean Nyekjær wrote:
>> Hi all
>>
>> I'm in the process of creating a custom BSP with an ad5755 dac. It an
>> requirement to be able to switch between voltage and current mode per
>> channel from userspace.
>> Is it possible with the current iio interface?
>> Is there a feature in the pipeline where it's possible to do this switch?
>>
>> Regards
>> Sean Nyekjær--
>> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: DAC switch between current and voltage mode

[Jonathan Cameron]

On 24/08/15 19:44, Lars-Peter Clausen wrote:
> On 08/24/2015 08:44 AM, Sean Nyekjær wrote:
>> Hi Lars-Peter
>>
>> Sorry the write again. Is the possible with the current iio interface to
>> switch a dac from voltage to current mode from userspace?
>> If not, will upstream be interrested in a patch if it's possible?
> 
> Hi,
> 
> Currently this does not work. A patch to add support for this is certainly
> welcome. I'm just not sure what the interface for this should look like.
> Maybe register both a current and a voltage channel and only allow one of
> them to be powered at a time.
That's certainly my initial thought on an interface as well... The only tricky
bit is what a read back of the 'other' channels value should report.  Perhaps
return -EBUSY?

Jonathan
> 
> - Lars
> 
> 
>>
>> Regards
>> Sean Nyekjær
>>
>> On 2015-08-20 11:57, Sean Nyekjær wrote:
>>> Hi all
>>>
>>> I'm in the process of creating a custom BSP with an ad5755 dac. It an
>>> requirement to be able to switch between voltage and current mode per
>>> channel from userspace.
>>> Is it possible with the current iio interface?
>>> Is there a feature in the pipeline where it's possible to do this switch?
>>>
>>> Regards
>>> Sean Nyekjær--
>>> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
> 
> --
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>