[PATCH v2 3/4] iio: adc: at91_adc: add Kconfig dependency on the OF symbol

[Alexandru Ardelean]

This tries to solve a warning reported by the lkp bot:

>> drivers/iio/adc/at91_adc.c:1439:34: warning: unused variable
>> 'at91_adc_dt_ids' [-Wunused-const-variable]
   static const struct of_device_id at91_adc_dt_ids[] = {
                                    ^
   1 warning generated.

This shows up with 'compiler: clang version 12.0.0' and W=1 (as the bot
mentions).

Forward declarations for global variables can be a bit weird; forward
function declarations are more common.

Maybe another fix for this would have been to prefix with 'extern' the
'at91_adc_dt_ids' variable, thus making it more friendly as a forward
declaration. It would look weird, but it would work.

But, we can avoid that forward declaration altogether simply by obtaining
the private data with of_device_get_match_data().

This appeared after commit 4027860dcc4c ("iio: Kconfig: at91_adc: add
COMPILE_TEST dependency to driver"), which put this driver on the lkp's bot
radar.

Fixes: 4027860dcc4c ("iio: Kconfig: at91_adc: add COMPILE_TEST dependency to driver")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
---
 drivers/iio/adc/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 91ae90514aff..17e9ceb9c6c4 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -295,7 +295,7 @@ config ASPEED_ADC
 config AT91_ADC
 	tristate "Atmel AT91 ADC"
 	depends on ARCH_AT91 || COMPILE_TEST
-	depends on INPUT && SYSFS
+	depends on INPUT && SYSFS && OF
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
 	help
-- 
2.17.1