iio: adc: Add battery channel definition for ADC

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>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c
index 4be44c524b4daa9d7842de0df57cda4f21c2861b..8eebaa3dc53481bbd24fea76ef2fd7ed8fb47ed6 100644 (file)
--- 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