iio: adc: axp20x_adc: Minor code cleanups

The code may be clearer if parameters are not re-purposed to hold
temporary results like register values, so introduce local variables
as necessary to avoid that. Regroup macros based on chip type, and
use the FIELD_PREP() macro instead of a hand-rolled version.
Suggested-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
Link: https://lore.kernel.org/r/20230217153404.32481-1-aidanmacdonald.0x0@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/axp20x_adc.c

@@ -5,6 +5,7 @@
  *	Quentin Schulz <quentin.schulz@free-electrons.com>
  */
 
+#include <linux/bitfield.h>
 #include <linux/completion.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
@@ -22,20 +23,20 @@
 #include <linux/mfd/axp20x.h>
 
 #define AXP20X_ADC_EN1_MASK			GENMASK(7, 0)
-
 #define AXP20X_ADC_EN2_MASK			(GENMASK(3, 2) | BIT(7))
+
 #define AXP22X_ADC_EN1_MASK			(GENMASK(7, 5) | BIT(0))
 
 #define AXP20X_GPIO10_IN_RANGE_GPIO0		BIT(0)
 #define AXP20X_GPIO10_IN_RANGE_GPIO1		BIT(1)
-#define AXP20X_GPIO10_IN_RANGE_GPIO0_VAL(x)	((x) & BIT(0))
-#define AXP20X_GPIO10_IN_RANGE_GPIO1_VAL(x)	(((x) & BIT(0)) << 1)
 
 #define AXP20X_ADC_RATE_MASK			GENMASK(7, 6)
-#define AXP813_V_I_ADC_RATE_MASK		GENMASK(5, 4)
-#define AXP813_ADC_RATE_MASK			(AXP20X_ADC_RATE_MASK | AXP813_V_I_ADC_RATE_MASK)
 #define AXP20X_ADC_RATE_HZ(x)			((ilog2((x) / 25) << 6) & AXP20X_ADC_RATE_MASK)
+
 #define AXP22X_ADC_RATE_HZ(x)			((ilog2((x) / 100) << 6) & AXP20X_ADC_RATE_MASK)
+
+#define AXP813_V_I_ADC_RATE_MASK		GENMASK(5, 4)
+#define AXP813_ADC_RATE_MASK			(AXP20X_ADC_RATE_MASK | AXP813_V_I_ADC_RATE_MASK)
 #define AXP813_TS_GPIO0_ADC_RATE_HZ(x)		AXP20X_ADC_RATE_HZ(x)
 #define AXP813_V_I_ADC_RATE_HZ(x)		((ilog2((x) / 100) << 4) & AXP813_V_I_ADC_RATE_MASK)
 #define AXP813_ADC_RATE_HZ(x)			(AXP20X_ADC_RATE_HZ(x) | AXP813_V_I_ADC_RATE_HZ(x))
@@ -234,7 +235,7 @@ static int axp20x_adc_raw(struct iio_dev *indio_dev,
 			  struct iio_chan_spec const *chan, int *val)
 {
 	struct axp20x_adc_iio *info = iio_priv(indio_dev);
-	int size = 12;
+	int ret, size;
 
 	/*
 	 * N.B.:  Unlike the Chinese datasheets tell, the charging current is
@@ -246,10 +247,11 @@ static int axp20x_adc_raw(struct iio_dev *indio_dev,
 	else
 		size = 12;
 
-	*val = axp20x_read_variable_width(info->regmap, chan->address, size);
-	if (*val < 0)
-		return *val;
+	ret = axp20x_read_variable_width(info->regmap, chan->address, size);
+	if (ret < 0)
+		return ret;
 
+	*val = ret;
 	return IIO_VAL_INT;
 }
 
@@ -257,11 +259,13 @@ static int axp22x_adc_raw(struct iio_dev *indio_dev,
 			  struct iio_chan_spec const *chan, int *val)
 {
 	struct axp20x_adc_iio *info = iio_priv(indio_dev);
+	int ret;
 
-	*val = axp20x_read_variable_width(info->regmap, chan->address, 12);
-	if (*val < 0)
-		return *val;
+	ret = axp20x_read_variable_width(info->regmap, chan->address, 12);
+	if (ret < 0)
+		return ret;
 
+	*val = ret;
 	return IIO_VAL_INT;
 }
 
@@ -269,11 +273,13 @@ static int axp813_adc_raw(struct iio_dev *indio_dev,
 			  struct iio_chan_spec const *chan, int *val)
 {
 	struct axp20x_adc_iio *info = iio_priv(indio_dev);
+	int ret;
 
-	*val = axp20x_read_variable_width(info->regmap, chan->address, 12);
-	if (*val < 0)
-		return *val;
+	ret = axp20x_read_variable_width(info->regmap, chan->address, 12);
+	if (ret < 0)
+		return ret;
 
+	*val = ret;
 	return IIO_VAL_INT;
 }
 
@@ -443,27 +449,27 @@ static int axp20x_adc_offset_voltage(struct iio_dev *indio_dev, int channel,
 				     int *val)
 {
 	struct axp20x_adc_iio *info = iio_priv(indio_dev);
+	unsigned int regval;
 	int ret;
 
-	ret = regmap_read(info->regmap, AXP20X_GPIO10_IN_RANGE, val);
+	ret = regmap_read(info->regmap, AXP20X_GPIO10_IN_RANGE, &regval);
 	if (ret < 0)
 		return ret;
 
 	switch (channel) {
 	case AXP20X_GPIO0_V:
-		*val &= AXP20X_GPIO10_IN_RANGE_GPIO0;
+		regval = FIELD_GET(AXP20X_GPIO10_IN_RANGE_GPIO0, regval);
 		break;
 
 	case AXP20X_GPIO1_V:
-		*val &= AXP20X_GPIO10_IN_RANGE_GPIO1;
+		regval = FIELD_GET(AXP20X_GPIO10_IN_RANGE_GPIO1, regval);
 		break;
 
 	default:
 		return -EINVAL;
 	}
 
-	*val = *val ? 700000 : 0;
-
+	*val = regval ? 700000 : 0;
 	return IIO_VAL_INT;
 }
 
@@ -548,7 +554,7 @@ static int axp20x_write_raw(struct iio_dev *indio_dev,
 			    long mask)
 {
 	struct axp20x_adc_iio *info = iio_priv(indio_dev);
-	unsigned int reg, regval;
+	unsigned int regmask, regval;
 
 	/*
 	 * The AXP20X PMIC allows the user to choose between 0V and 0.7V offsets
@@ -560,25 +566,22 @@ static int axp20x_write_raw(struct iio_dev *indio_dev,
 	if (val != 0 && val != 700000)
 		return -EINVAL;
 
-	val = val ? 1 : 0;
-
 	switch (chan->channel) {
 	case AXP20X_GPIO0_V:
-		reg = AXP20X_GPIO10_IN_RANGE_GPIO0;
-		regval = AXP20X_GPIO10_IN_RANGE_GPIO0_VAL(val);
+		regmask = AXP20X_GPIO10_IN_RANGE_GPIO0;
+		regval = FIELD_PREP(AXP20X_GPIO10_IN_RANGE_GPIO0, !!val);
 		break;
 
 	case AXP20X_GPIO1_V:
-		reg = AXP20X_GPIO10_IN_RANGE_GPIO1;
-		regval = AXP20X_GPIO10_IN_RANGE_GPIO1_VAL(val);
+		regmask = AXP20X_GPIO10_IN_RANGE_GPIO1;
+		regval = FIELD_PREP(AXP20X_GPIO10_IN_RANGE_GPIO1, !!val);
 		break;
 
 	default:
 		return -EINVAL;
 	}
 
-	return regmap_update_bits(info->regmap, AXP20X_GPIO10_IN_RANGE, reg,
-				  regval);
+	return regmap_update_bits(info->regmap, AXP20X_GPIO10_IN_RANGE, regmask, regval);
 }
 
 static const struct iio_info axp20x_adc_iio_info = {