[PATCH v3 7/8] iio: adc: ti-ads1015: replace custom shift macros with FIELD_PREP/GET

The driver currently uses custom _SHIFT macros and manual bitwise
operations to read and write to the configuration register.

Modernize the bitwise logic by replacing all manual shifts with the
standard FIELD_PREP() and FIELD_GET() macros from <linux/bitfield.h>.
This improves readability and prevents potential bitwise errors.

Remove the now-unused _SHIFT macros from the top of the file.

Suggested-by: Jonathan Cameron <[email protected]>
Signed-off-by: Archit Anant <[email protected]>
---
 drivers/iio/adc/ti-ads1015.c | 39 ++++++++++++++++--------------------
 1 file changed, 17 insertions(+), 22 deletions(-)

diff --git a/drivers/iio/adc/ti-ads1015.c b/drivers/iio/adc/ti-ads1015.c
index f92ec5941c47..3c78d85321e0 100644
--- a/drivers/iio/adc/ti-ads1015.c
+++ b/drivers/iio/adc/ti-ads1015.c
@@ -11,6 +11,7 @@
  *	* 0x4B - ADDR connected to SCL
  */
 
+#include <linux/bitfield.h>
 #include <linux/cleanup.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
@@ -39,14 +40,7 @@
 #define ADS1015_LO_THRESH_REG	0x02
 #define ADS1015_HI_THRESH_REG	0x03
 
-#define ADS1015_CFG_COMP_QUE_SHIFT	0
-#define ADS1015_CFG_COMP_LAT_SHIFT	2
-#define ADS1015_CFG_COMP_POL_SHIFT	3
-#define ADS1015_CFG_COMP_MODE_SHIFT	4
-#define ADS1015_CFG_DR_SHIFT	5
 #define ADS1015_CFG_MOD_SHIFT	8
-#define ADS1015_CFG_PGA_SHIFT	9
-#define ADS1015_CFG_MUX_SHIFT	12
 
 #define ADS1015_CFG_COMP_QUE_MASK	GENMASK(1, 0)
 #define ADS1015_CFG_COMP_LAT_MASK	BIT(2)
@@ -408,15 +402,15 @@ int ads1015_get_adc_result(struct ads1015_data *data, int chan, int *val)
 	dr = data->channel_data[chan].data_rate;
 	mask = ADS1015_CFG_MUX_MASK | ADS1015_CFG_PGA_MASK |
 		ADS1015_CFG_DR_MASK;
-	cfg = chan << ADS1015_CFG_MUX_SHIFT | pga << ADS1015_CFG_PGA_SHIFT |
-		dr << ADS1015_CFG_DR_SHIFT;
+	cfg = FIELD_PREP(ADS1015_CFG_MUX_MASK, chan) | FIELD_PREP(ADS1015_CFG_PGA_MASK, pga) |
+		FIELD_PREP(ADS1015_CFG_DR_MASK, dr);
 
 	if (ads1015_event_channel_enabled(data)) {
 		mask |= ADS1015_CFG_COMP_QUE_MASK | ADS1015_CFG_COMP_MODE_MASK;
-		cfg |= data->thresh_data[chan].comp_queue <<
-				ADS1015_CFG_COMP_QUE_SHIFT |
-			data->comp_mode <<
-				ADS1015_CFG_COMP_MODE_SHIFT;
+		cfg |= FIELD_PREP(ADS1015_CFG_COMP_QUE_MASK,
+				  data->thresh_data[chan].comp_queue) |
+			FIELD_PREP(ADS1015_CFG_COMP_MODE_MASK,
+				   data->comp_mode);
 	}
 
 	cfg = (old & ~mask) | (cfg & mask);
@@ -427,7 +421,7 @@ int ads1015_get_adc_result(struct ads1015_data *data, int chan, int *val)
 		data->conv_invalid = true;
 	}
 	if (data->conv_invalid) {
-		dr_old = (old & ADS1015_CFG_DR_MASK) >> ADS1015_CFG_DR_SHIFT;
+		dr_old = FIELD_GET(ADS1015_CFG_DR_MASK, old);
 		conv_time = DIV_ROUND_UP(USEC_PER_SEC, data_rate[dr_old]);
 		conv_time += DIV_ROUND_UP(USEC_PER_SEC, data_rate[dr]);
 		conv_time += conv_time / 10; /* 10% internal clock inaccuracy */
@@ -758,8 +752,8 @@ static int ads1015_disable_event_config(struct ads1015_data *data,
 
 	ret = regmap_update_bits(data->regmap, ADS1015_CFG_REG,
 				ADS1015_CFG_COMP_QUE_MASK,
-				ADS1015_CFG_COMP_DISABLE <<
-					ADS1015_CFG_COMP_QUE_SHIFT);
+				FIELD_PREP(ADS1015_CFG_COMP_QUE_MASK,
+					   ADS1015_CFG_COMP_DISABLE));
 	if (ret)
 		return ret;
 
@@ -999,19 +993,20 @@ static int ads1015_probe(struct i2c_client *client)
 		unsigned int cfg_comp_mask = ADS1015_CFG_COMP_QUE_MASK |
 			ADS1015_CFG_COMP_LAT_MASK | ADS1015_CFG_COMP_POL_MASK;
 		unsigned int cfg_comp =
-			ADS1015_CFG_COMP_DISABLE << ADS1015_CFG_COMP_QUE_SHIFT |
-			1 << ADS1015_CFG_COMP_LAT_SHIFT;
+			FIELD_PREP(ADS1015_CFG_COMP_QUE_MASK,
+				   ADS1015_CFG_COMP_DISABLE) |
+			FIELD_PREP(ADS1015_CFG_COMP_LAT_MASK, 1);
 
 		switch (irq_trig) {
 		case IRQF_TRIGGER_FALLING:
 		case IRQF_TRIGGER_LOW:
-			cfg_comp |= ADS1015_CFG_COMP_POL_LOW <<
-					ADS1015_CFG_COMP_POL_SHIFT;
+			cfg_comp |= FIELD_PREP(ADS1015_CFG_COMP_POL_MASK,
+					       ADS1015_CFG_COMP_POL_LOW);
 			break;
 		case IRQF_TRIGGER_HIGH:
 		case IRQF_TRIGGER_RISING:
-			cfg_comp |= ADS1015_CFG_COMP_POL_HIGH <<
-					ADS1015_CFG_COMP_POL_SHIFT;
+			cfg_comp |= FIELD_PREP(ADS1015_CFG_COMP_POL_MASK,
+					       ADS1015_CFG_COMP_POL_HIGH);
 			break;
 		default:
 			return -EINVAL;
-- 
2.39.5