Groups > linux.kernel > #1592094

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

From	Lars-Peter Clausen <lars@metafoo.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 6/6] iio: adc: stm32: add support for EXTI trigger
Date	2017-03-03 17:00 +0100
Message-ID	<tgXMC-3jh-27@gated-at.bofh.it> (permalink)
References	<tfTBn-7wT-7@gated-at.bofh.it> <tfTBn-7wT-5@gated-at.bofh.it> <tgUOK-1js-19@gated-at.bofh.it> <tgWxc-2tg-27@gated-at.bofh.it> <tgXMC-3jh-23@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

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?
>

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

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

csiph-web