On 09/10/2017 06:00 PM, Jonathan Cameron wrote:
> On Wed, 6 Sep 2017 18:16:33 +0200
> Fabrice Gasnier <fabrice.gasnier@xxxxxx> wrote:
>
>> On 09/06/2017 02:56 PM, Arnd Bergmann wrote:
>>> The ADC driver can trigger on either the timer or the lptim
>>> trigger, but it only uses a Kconfig 'select' statement
>>> to ensure that the first of the two is present. When the lptim
>>> trigger is enabled as a loadable module, and the adc driver
>>> is built-in, we now get a link error:
>>>
>>> drivers/iio/adc/stm32-adc.o: In function `stm32_adc_get_trig_extsel':
>>> stm32-adc.c:(.text+0x4e0): undefined reference to `is_stm32_lptim_trigger'
>>>
>>> We could use a second 'select' statement and always have both
>>> trigger drivers enabled when the adc driver is, but it seems that
>>> the lptimer trigger was intentionally left optional, so it seems
>>> better to keep it that way.
>> Hi Arnd,
>>
>> This is correct, not all stm32 have this hardware.
>>>
>>> This adds a hack to use 'IS_REACHABLE()' rather than 'IS_ENABLED()',
>>> which avoids the link error, but instead leads to the lptimer trigger
>>> not being used in the broken configuration. I've added a runtime
>>> warning for this case to help users figure out what they did wrong
>>> if this should ever be done by accident.
>>>
>>> Fixes: f0b638a7f6db ("iio: adc: stm32: add support for lptimer triggers")
>>> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
>> Tested-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
>
> This may take me a few weeks to pick up. I don't want to
> pull the mfd immutable branch in just to have this fix, so this will
> get sorted after rc1 is out.
>
> As ever, poke me if it looks like I've forgotten about it.
Hi Jonathan,
Di you apply this one?
Thanks,
Best Regards,
Fabrice
> Sorry for the delay!
>
> Jonathan
>
>>
>> Many thanks for the fix,
>> Best Regards,
>> Fabrice
>>> ---
>>> include/linux/iio/timer/stm32-lptim-trigger.h | 5 ++++-
>>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/include/linux/iio/timer/stm32-lptim-trigger.h b/include/linux/iio/timer/stm32-lptim-trigger.h
>>> index 34d59bfdce2d..464458d20b16 100644
>>> --- a/include/linux/iio/timer/stm32-lptim-trigger.h
>>> +++ b/include/linux/iio/timer/stm32-lptim-trigger.h
>>> @@ -16,11 +16,14 @@
>>> #define LPTIM2_OUT "lptim2_out"
>>> #define LPTIM3_OUT "lptim3_out"
>>>
>>> -#if IS_ENABLED(CONFIG_IIO_STM32_LPTIMER_TRIGGER)
>>> +#if IS_REACHABLE(CONFIG_IIO_STM32_LPTIMER_TRIGGER)
>>> bool is_stm32_lptim_trigger(struct iio_trigger *trig);
>>> #else
>>> static inline bool is_stm32_lptim_trigger(struct iio_trigger *trig)
>>> {
>>> +#if IS_ENABLED(CONFIG_IIO_STM32_LPTIMER_TRIGGER)
>>> + pr_warn_once("stm32 lptim_trigger not linked in\n");
>>> +#endif
>>> return false;
>>> }
>>> #endif
>>>
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