[PATCH v2] iio: adc: aspeed: clear reference voltage bits before configuring vref

[Billy Tsai]

Ensures the reference voltage bits are cleared in the ADC engine
control register before configuring the voltage reference. This
avoids potential misconfigurations caused by residual bits.

Signed-off-by: Billy Tsai <billy_tsai at aspeedtech.com>
---
 drivers/iio/adc/aspeed_adc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c
index 1d5fd5f534b8..8ab29948214a 100644
--- a/drivers/iio/adc/aspeed_adc.c
+++ b/drivers/iio/adc/aspeed_adc.c
@@ -415,6 +415,7 @@ static int aspeed_adc_vref_config(struct iio_dev *indio_dev)
 	}
 	adc_engine_control_reg_val =
 		readl(data->base + ASPEED_REG_ENGINE_CONTROL);
+	adc_engine_control_reg_val &= ~ASPEED_ADC_REF_VOLTAGE;
 
 	ret = devm_regulator_get_enable_read_voltage(data->dev, "vref");
 	if (ret < 0 && ret != -ENODEV)
-- 
2.25.1