JESD204B support

JESD204B support

[Shubhrajyoti Datta]

Hi ,

I was wondering if there is any plans or existing support for JESD204B.
I was thinking of IIO. However any other ideas may be welcome.


With Regards,
Shubhrajyoti

Re: JESD204B support

[Lars-Peter Clausen]

On 06/18/2015 02:46 PM, Shubhrajyoti Datta wrote:
> Hi ,
>
> I was wondering if there is any plans or existing support for JESD204B.
> I was thinking of IIO. However any other ideas may be welcome.

Yes, IIO is the way to go. We have some out-of-tree drivers for JESD204B 
chips. They are not quite ready yet, but we'll get there.

- Lars

Re: JESD204B support

[Shubhrajyoti Datta]

On Thu, Jun 18, 2015 at 8:44 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
> On 06/18/2015 02:46 PM, Shubhrajyoti Datta wrote:
>>
>> Hi ,
>>
>> I was wondering if there is any plans or existing support for JESD204B.
>> I was thinking of IIO. However any other ideas may be welcome.
>
>
> Yes, IIO is the way to go. We have some out-of-tree drivers for JESD204B
> chips.

Great.

> They are not quite ready yet,  but we'll get there
May be sharing early could get some alignment.


The thing is the data rate change and the related clock tree
dependencies that it may bring.
That part looked tricky to me. So thought of talking to the community
before sketching something
not compatible. :-)

>
> - Lars
>

Re: JESD204B support

[Lars-Peter Clausen]

On 06/19/2015 08:45 AM, Shubhrajyoti Datta wrote:
> On Thu, Jun 18, 2015 at 8:44 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
>> On 06/18/2015 02:46 PM, Shubhrajyoti Datta wrote:
>>>
>>> Hi ,
>>>
>>> I was wondering if there is any plans or existing support for JESD204B.
>>> I was thinking of IIO. However any other ideas may be welcome.
>>
>>
>> Yes, IIO is the way to go. We have some out-of-tree drivers for JESD204B
>> chips.
>
> Great.
>
>> They are not quite ready yet,  but we'll get there
> May be sharing early could get some alignment.

It mostly all at 
https://github.com/analogdevicesinc/linux/blob/xcomm_zynq/drivers/iio/adc/

E.g. 
https://github.com/analogdevicesinc/linux/blob/xcomm_zynq/drivers/iio/adc/cf_axi_jesd204b_v51.c 
and 
https://github.com/analogdevicesinc/linux/blob/xcomm_zynq/drivers/iio/adc/cf_axi_adc_core.c

But it is nothing you'd want to copy infrastructure wise. The drivers have a 
lot of built-in assumptions about the underlying topology and will really 
only work with a certain JESD converter and JESD host controller combination.

>
>
> The thing is the data rate change and the related clock tree
> dependencies that it may bring.
> That part looked tricky to me. So thought of talking to the community
> before sketching something
> not compatible. :-)

Yeah, I think that's one of the parts we haven't really figured out yet. The 
JESD transceiver that we are using on the host system unfortunately is not 
re-programmable at runtime.

But otherwise we are using the normal clock framework to model the various 
clock relationships and use it to enable/disable and setup the clocks as 
required.

- Lars

Re: JESD204B support

[Shubhrajyoti Datta]

On Fri, Jun 19, 2015 at 1:40 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
> On 06/19/2015 08:45 AM, Shubhrajyoti Datta wrote:
>>
>> On Thu, Jun 18, 2015 at 8:44 PM, Lars-Peter Clausen <lars@metafoo.de>
>> wrote:
>>>
>>> On 06/18/2015 02:46 PM, Shubhrajyoti Datta wrote:
>>>>
>>>>
>>>> Hi ,
>>>>
>>>> I was wondering if there is any plans or existing support for JESD204B.
>>>> I was thinking of IIO. However any other ideas may be welcome.
>>>
>>>
>>>
>>> Yes, IIO is the way to go. We have some out-of-tree drivers for JESD204B
>>> chips.
>>
>>
>> Great.
>>
>>> They are not quite ready yet,  but we'll get there
>>
>> May be sharing early could get some alignment.
>
>
> It mostly all at
> https://github.com/analogdevicesinc/linux/blob/xcomm_zynq/drivers/iio/adc/
>
> E.g.
> https://github.com/analogdevicesinc/linux/blob/xcomm_zynq/drivers/iio/adc/cf_axi_jesd204b_v51.c
> and
> https://github.com/analogdevicesinc/linux/blob/xcomm_zynq/drivers/iio/adc/cf_axi_adc_core.c
>
> But it is nothing you'd want to copy infrastructure wise. The drivers have a
> lot of built-in assumptions about the underlying topology and will really
> only work with a certain JESD converter and JESD host controller
> combination.

OK still good stuff.

>
>>
>>
>> The thing is the data rate change and the related clock tree
>> dependencies that it may bring.
>> That part looked tricky to me. So thought of talking to the community
>> before sketching something
>> not compatible. :-)
>
>
> Yeah, I think that's one of the parts we haven't really figured out yet. The
> JESD transceiver that we are using on the host system unfortunately is not
> re-programmable at runtime.
>
> But otherwise we are using the normal clock framework to model the various
> clock relationships and use it to enable/disable and setup the clocks as
> required.

Thanks for the  heads up.
>
> - Lars
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