Arnd Bergmann 6d745ee8b5 iio: stm32: fix adc/trigger link error ... 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. 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: f0b638a7f6 ("iio: adc: stm32: add support for lptimer triggers") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>		2017-12-02 11:21:31 +00:00
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stm32-lptim-trigger.h
stm32-timer-trigger.h