Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1591919 > unrolled thread

Re: [PATCH v3 6/6] iio: adc: stm32: add support for EXTI trigger

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: [PATCH v3 6/6] iio: adc: stm32: add support for EXTI trigger Lars-Peter Clausen <lars@metafoo.de> - 2017-03-03 13:50 +0100
    Re: [PATCH v3 6/6] iio: adc: stm32: add support for EXTI trigger Fabrice Gasnier <fabrice.gasnier@st.com> - 2017-03-03 15:40 +0100
      Re: [PATCH v3 6/6] iio: adc: stm32: add support for EXTI trigger Lars-Peter Clausen <lars@metafoo.de> - 2017-03-03 17:00 +0100
        Re: [PATCH v3 6/6] iio: adc: stm32: add support for EXTI trigger Lars-Peter Clausen <lars@metafoo.de> - 2017-03-03 17:00 +0100

#1591919 — Re: [PATCH v3 6/6] iio: adc: stm32: add support for EXTI trigger

On 02/28/2017 05:51 PM, Fabrice Gasnier wrote:
> EXTi (external interrupt) signal can be routed internally as trigger
> source for ADC conversions: STM32F4 ADC can use EXTI11.
> 
> Retrieve interrupt trigger from DT, so it can be muxed into ADC IP,
> via extsel.

Hi,

Sorry, I have some trouble understanding the specifics of this. Is EXTI a
hardware input signal into the ADC that automatically triggers a conversion
when asserted? If yes how is it configured which external signal is used
here. Your bindings suggest that any GPIO can be used, but the driver only
differentiates between EXTI on or EXTI off.

Or is this just a software triggered conversion? The GPIO triggers a
software interrupt routine and the interrupt routine than triggers conversion?

[toc] | [next] | [standalone]

#1591998

On 03/03/2017 12:45 PM, Lars-Peter Clausen wrote:
> On 02/28/2017 05:51 PM, Fabrice Gasnier wrote:
>> EXTi (external interrupt) signal can be routed internally as trigger
>> source for ADC conversions: STM32F4 ADC can use EXTI11.
>>
>> Retrieve interrupt trigger from DT, so it can be muxed into ADC IP,
>> via extsel.
> 
> Hi,
> 
> Sorry, I have some trouble understanding the specifics of this. Is EXTI a
> hardware input signal into the ADC that automatically triggers a conversion
> when asserted? If yes how is it configured which external signal is used
> here. Your bindings suggest that any GPIO can be used, but the driver only
> differentiates between EXTI on or EXTI off.
Hi Lars,

Yes, STM32 EXTI is external interrupt/event line. In case of STM32 ADC,
EXTI11 signal can be used to start a conversion. In this case, it must
be selected inside ADC IP using extsel bitfield. This EXTI11 line can
mapped from any GPIO bank A,B... line 11 (e.g. PA11 or PB11...) by using
interrupt binding.
This is why I expose this in DT.

> 
> Or is this just a software triggered conversion? The GPIO triggers a
> software interrupt routine and the interrupt routine than triggers conversion?
> 

[toc] | [prev] | [next] | [standalone]

#1592093

On 03/03/2017 02:00 PM, Fabrice Gasnier wrote:
> On 03/03/2017 12:45 PM, Lars-Peter Clausen wrote:
>> On 02/28/2017 05:51 PM, Fabrice Gasnier wrote:
>>> EXTi (external interrupt) signal can be routed internally as trigger
>>> source for ADC conversions: STM32F4 ADC can use EXTI11.
>>>
>>> Retrieve interrupt trigger from DT, so it can be muxed into ADC IP,
>>> via extsel.
>>
>> Hi,
>>
>> Sorry, I have some trouble understanding the specifics of this. Is EXTI a
>> hardware input signal into the ADC that automatically triggers a conversion
>> when asserted? If yes how is it configured which external signal is used
>> here. Your bindings suggest that any GPIO can be used, but the driver only
>> differentiates between EXTI on or EXTI off.
> Hi Lars,
> 
> Yes, STM32 EXTI is external interrupt/event line. In case of STM32 ADC,
> EXTI11 signal can be used to start a conversion. In this case, it must
> be selected inside ADC IP using extsel bitfield. This EXTI11 line can
> mapped from any GPIO bank A,B... line 11 (e.g. PA11 or PB11...) by using
> interrupt binding.
> This is why I expose this in DT.

How is the mapping? That's the part I don't understand. How does requesting
the IRQ for the GPIO as a generic software IRQ establish the hardware
connection between the GPIO block and the ADC?

[toc] | [prev] | [next] | [standalone]

#1592094

On 03/03/2017 04:46 PM, Lars-Peter Clausen wrote:
> On 03/03/2017 02:00 PM, Fabrice Gasnier wrote:
>> On 03/03/2017 12:45 PM, Lars-Peter Clausen wrote:
>>> On 02/28/2017 05:51 PM, Fabrice Gasnier wrote:
>>>> EXTi (external interrupt) signal can be routed internally as trigger
>>>> source for ADC conversions: STM32F4 ADC can use EXTI11.
>>>>
>>>> Retrieve interrupt trigger from DT, so it can be muxed into ADC IP,
>>>> via extsel.
>>>
>>> Hi,
>>>
>>> Sorry, I have some trouble understanding the specifics of this. Is EXTI a
>>> hardware input signal into the ADC that automatically triggers a conversion
>>> when asserted? If yes how is it configured which external signal is used
>>> here. Your bindings suggest that any GPIO can be used, but the driver only
>>> differentiates between EXTI on or EXTI off.
>> Hi Lars,
>>
>> Yes, STM32 EXTI is external interrupt/event line. In case of STM32 ADC,
>> EXTI11 signal can be used to start a conversion. In this case, it must
>> be selected inside ADC IP using extsel bitfield. This EXTI11 line can
>> mapped from any GPIO bank A,B... line 11 (e.g. PA11 or PB11...) by using
>> interrupt binding.
>> This is why I expose this in DT.
> 
> How is the mapping? That's the part I don't understand. How does requesting

How is the mapping done?

> the IRQ for the GPIO as a generic software IRQ establish the hardware
> connection between the GPIO block and the ADC?
> 

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web