Use buffer without trigger

Use buffer without trigger

[Denis Ciocca]

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Hi all,

I have one question about iio device. I want create with only one physical
device a lot of iio devices because I want to activate each 'sensor'
without stop the buffer and reactivate with more channels.
But, I want to use only one trigger, for example of the major iio device.
It is possible to register only a buffer of one device and use the trigger
of another one?

Thanks
Denis

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Re: Use buffer without trigger

[Lars-Peter Clausen]

On 05/14/2013 06:18 PM, Denis Ciocca wrote:
> Hi all,
> 
> I have one question about iio device. I want create with only one physical
> device a lot of iio devices because I want to activate each 'sensor'
> without stop the buffer and reactivate with more channels.
> But, I want to use only one trigger, for example of the major iio device.
> It is possible to register only a buffer of one device and use the trigger
> of another one?

Simple answer: yes.

- Lars

Re: Use buffer without trigger

[Denis CIOCCA]

I've tried to register a buffer on one iio device, but when I try to enable=
 it=20
the error massage is about the no trigger available.
I don't want a trigger for this device, I want use only one trigger of anot=
her=20
iio device for all. It is possible?
Thanks,

Denis


On Tuesday, May 14, 2013 07:57:03 PM Lars-Peter Clausen wrote:
> On 05/14/2013 06:18 PM, Denis Ciocca wrote:
> > Hi all,
> >=20
> > I have one question about iio device. I want create with only one physi=
cal
> > device a lot of iio devices because I want to activate each 'sensor'
> > without stop the buffer and reactivate with more channels.
> > But, I want to use only one trigger, for example of the major iio devic=
e.
> > It is possible to register only a buffer of one device and use the trig=
ger
> > of another one?
>=20
> Simple answer: yes.
>=20
> - Lars
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Re: Use buffer without trigger

[Lars-Peter Clausen]

On 05/17/2013 01:28 PM, Denis CIOCCA wrote:
> I've tried to register a buffer on one iio device, but when I try to enable it 
> the error massage is about the no trigger available.
> I don't want a trigger for this device, I want use only one trigger of another 
> iio device for all. It is possible?
> Thanks,
> 
> Denis

Yes, but you still have to assign the trigger to the device in sysfs.

- Lars

Re: Use buffer without trigger

[Denis CIOCCA]

> Yes, but you still have to assign the trigger to the device in sysfs.

Ok but I have to use a dummy trigger for every device?

Denis=

Re: Use buffer without trigger

[Lars-Peter Clausen]

On 05/17/2013 02:34 PM, Denis CIOCCA wrote:
>> Yes, but you still have to assign the trigger to the device in sysfs.
> 
> Ok but I have to use a dummy trigger for every device?
> 
> Denis

No. Allocate your buffers and allocate your one trigger. Before you can
enable your buffer you need to assign the trigger to the buffer in sysfs (By
writing to trigger/current_trigger).

- Lars

Re: Use buffer without trigger

[Jonathan Cameron]

On 05/17/2013 01:52 PM, Lars-Peter Clausen wrote:
> On 05/17/2013 02:34 PM, Denis CIOCCA wrote:
>>> Yes, but you still have to assign the trigger to the device in sysfs.
>>
>> Ok but I have to use a dummy trigger for every device?
>>
>> Denis
> 
> No. Allocate your buffers and allocate your one trigger. Before you can
> enable your buffer you need to assign the trigger to the buffer in sysfs (By
> writing to trigger/current_trigger).
> 
Lots of the ADC drivers do this.  See max1363 for example. No sign a trigger
but it definitely has a buffer.  Often these parts convert on demand but can
do it at very high rates.

Re: Use buffer without trigger

[Denis CIOCCA]

On Saturday, May 18, 2013 12:20:06 PM Jonathan Cameron wrote:
> On 05/17/2013 01:52 PM, Lars-Peter Clausen wrote:
> > On 05/17/2013 02:34 PM, Denis CIOCCA wrote:
> >>> Yes, but you still have to assign the trigger to the device in sysfs.
> >>=20
> >> Ok but I have to use a dummy trigger for every device?
> >>=20
> >> Denis
> >=20
> > No. Allocate your buffers and allocate your one trigger. Before you can
> > enable your buffer you need to assign the trigger to the buffer in sysf=
s
> > (By writing to trigger/current_trigger).
>=20
> Lots of the ADC drivers do this.  See max1363 for example. No sign a trig=
ger
> but it definitely has a buffer.  Often these parts convert on demand but
> can do it at very high rates.

Ok, I will look!

Thanks Jonathan & Lars,

Denis=

Re: Use buffer without trigger

[Denis CIOCCA]

> Lots of the ADC drivers do this.  See max1363 for example. No sign a trigger
> but it definitely has a buffer.  Often these parts convert on demand but
> can do it at very high rates.
I Jonathan,

I'm seeing the max1363 driver but I don't understand the caller of 
max1363_trigger_handler function.
Usually, the iio_trigger_generic_data_rdy_poll function inside the 
request_threaded_irq, call iio_trigger_poll function and I suppose that this 
function is the caller of handler declarated inside iio_triggered_buffer_setup.

Many thanks,
Denis