[PATCH v3 1/4] iio: adc: Add battery channel definition for ADC

[Billy Tsai <billy_tsai@aspeedtech.com>]

Defines a constant for the battery sensing channel, typically the last
channel of the ADC. Clarifies channel usage and improves code
readability.

Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
---
 drivers/iio/adc/aspeed_adc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c
index 4be44c524b4d..8eebaa3dc534 100644
--- a/drivers/iio/adc/aspeed_adc.c
+++ b/drivers/iio/adc/aspeed_adc.c
@@ -75,6 +75,8 @@
 
 #define ASPEED_ADC_INIT_POLLING_TIME	500
 #define ASPEED_ADC_INIT_TIMEOUT		500000
+/* Battery sensing is typically on the last channel */
+#define ASPEED_ADC_BATTERY_CHANNEL		7
 /*
  * When the sampling rate is too high, the ADC may not have enough charging
  * time, resulting in a low voltage value. Thus, the default uses a slow
@@ -285,7 +287,7 @@ static int aspeed_adc_read_raw(struct iio_dev *indio_dev,
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
-		if (data->battery_sensing && chan->channel == 7) {
+		if (data->battery_sensing && chan->channel == ASPEED_ADC_BATTERY_CHANNEL) {
 			adc_engine_control_reg_val =
 				readl(data->base + ASPEED_REG_ENGINE_CONTROL);
 			writel(adc_engine_control_reg_val |
@@ -309,7 +311,7 @@ static int aspeed_adc_read_raw(struct iio_dev *indio_dev,
 		return IIO_VAL_INT;
 
 	case IIO_CHAN_INFO_OFFSET:
-		if (data->battery_sensing && chan->channel == 7)
+		if (data->battery_sensing && chan->channel == ASPEED_ADC_BATTERY_CHANNEL)
 			*val = (data->cv * data->battery_mode_gain.mult) /
 			       data->battery_mode_gain.div;
 		else

-- 
2.34.1