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. Reported-by: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> --- drivers/iio/adc/at91_adc.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c index 9b2c548fae95..c9ec0a4a357e 100644 --- a/drivers/iio/adc/at91_adc.c +++ b/drivers/iio/adc/at91_adc.c @@ -829,8 +829,6 @@ static u32 calc_startup_ticks_9x5(u32 startup_time, u32 adc_clk_khz) return ticks; } -static const struct of_device_id at91_adc_dt_ids[]; - static int at91_adc_probe_dt_ts(struct device_node *node, struct at91_adc_state *st, struct device *dev) { @@ -878,8 +876,7 @@ static int at91_adc_probe_dt(struct iio_dev *idev, if (!node) return -EINVAL; - st->caps = (struct at91_adc_caps *) - of_match_device(at91_adc_dt_ids, &pdev->dev)->data; + st->caps = (struct at91_adc_caps *)of_device_get_match_data(&pdev->dev); st->use_external = of_property_read_bool(node, "atmel,adc-use-external-triggers"); -- 2.17.1