staging: iio: cdc: ad7746: Break up use of chan->address and use FIELD_PREP etc

Instead of encoding several different fields into chan->address use
an indirection to a separate per channel structure where the various
fields can be expressed in a more readable form.  This also allows
the register values to be constructed at runtime using FIELD_PREP().

Drop the now redundant _SHIFT macros.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220626122938.582107-9-jic23@kernel.org

drivers/staging/iio/cdc/ad7746.c

@@ -5,6 +5,7 @@
  * Copyright 2011 Analog Devices Inc.
  */
 
+#include <linux/bitfield.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/i2c.h>
@@ -50,11 +51,12 @@
 #define AD7746_CAPSETUP_CACHOP		BIT(0)
 
 /* Voltage/Temperature Setup Register Bit Designations (AD7746_REG_VT_SETUP) */
-#define AD7746_VTSETUP_VTEN		(1 << 7)
-#define AD7746_VTSETUP_VTMD_INT_TEMP	(0 << 5)
-#define AD7746_VTSETUP_VTMD_EXT_TEMP	(1 << 5)
-#define AD7746_VTSETUP_VTMD_VDD_MON	(2 << 5)
-#define AD7746_VTSETUP_VTMD_EXT_VIN	(3 << 5)
+#define AD7746_VTSETUP_VTEN		BIT(7)
+#define AD7746_VTSETUP_VTMD_MASK	GENMASK(6, 5)
+#define AD7746_VTSETUP_VTMD_INT_TEMP	0
+#define AD7746_VTSETUP_VTMD_EXT_TEMP	1
+#define AD7746_VTSETUP_VTMD_VDD_MON	2
+#define AD7746_VTSETUP_VTMD_EXT_VIN	3
 #define AD7746_VTSETUP_EXTREF		BIT(4)
 #define AD7746_VTSETUP_VTSHORT		BIT(1)
 #define AD7746_VTSETUP_VTCHOP		BIT(0)
@@ -66,23 +68,22 @@
 #define AD7746_EXCSETUP_NEXCB		BIT(4)
 #define AD7746_EXCSETUP_EXCA		BIT(3)
 #define AD7746_EXCSETUP_NEXCA		BIT(2)
-#define AD7746_EXCSETUP_EXCLVL(x)	(((x) & 0x3) << 0)
+#define AD7746_EXCSETUP_EXCLVL_MASK	GENMASK(1, 0)
 
 /* Config Register Bit Designations (AD7746_REG_CFG) */
-#define AD7746_CONF_VTFS_SHIFT		6
-#define AD7746_CONF_CAPFS_SHIFT		3
 #define AD7746_CONF_VTFS_MASK		GENMASK(7, 6)
 #define AD7746_CONF_CAPFS_MASK		GENMASK(5, 3)
-#define AD7746_CONF_MODE_IDLE		(0 << 0)
-#define AD7746_CONF_MODE_CONT_CONV	(1 << 0)
-#define AD7746_CONF_MODE_SINGLE_CONV	(2 << 0)
-#define AD7746_CONF_MODE_PWRDN		(3 << 0)
-#define AD7746_CONF_MODE_OFFS_CAL	(5 << 0)
-#define AD7746_CONF_MODE_GAIN_CAL	(6 << 0)
+#define AD7746_CONF_MODE_MASK		GENMASK(2, 0)
+#define AD7746_CONF_MODE_IDLE		0
+#define AD7746_CONF_MODE_CONT_CONV	1
+#define AD7746_CONF_MODE_SINGLE_CONV	2
+#define AD7746_CONF_MODE_PWRDN		3
+#define AD7746_CONF_MODE_OFFS_CAL	5
+#define AD7746_CONF_MODE_GAIN_CAL	6
 
 /* CAPDAC Register Bit Designations (AD7746_REG_CAPDACx) */
 #define AD7746_CAPDAC_DACEN		BIT(7)
-#define AD7746_CAPDAC_DACP(x)		((x) & 0x7F)
+#define AD7746_CAPDAC_DACP_MASK		GENMASK(6, 0)
 
 struct ad7746_chip_info {
 	struct i2c_client *client;
@@ -109,6 +110,52 @@ enum ad7746_chan {
 	CIN2_DIFF,
 };
 
+struct ad7746_chan_info {
+	u8 addr;
+	union {
+		u8 vtmd;
+		struct { /* CAP SETUP fields */
+			unsigned int cin2 : 1;
+			unsigned int capdiff : 1;
+		};
+	};
+};
+
+static const struct ad7746_chan_info ad7746_chan_info[] = {
+	[VIN] = {
+		.addr = AD7746_REG_VT_DATA_HIGH,
+		.vtmd = AD7746_VTSETUP_VTMD_EXT_VIN,
+	},
+	[VIN_VDD] = {
+		.addr = AD7746_REG_VT_DATA_HIGH,
+		.vtmd = AD7746_VTSETUP_VTMD_VDD_MON,
+	},
+	[TEMP_INT] = {
+		.addr = AD7746_REG_VT_DATA_HIGH,
+		.vtmd = AD7746_VTSETUP_VTMD_INT_TEMP,
+	},
+	[TEMP_EXT] = {
+		.addr = AD7746_REG_VT_DATA_HIGH,
+		.vtmd = AD7746_VTSETUP_VTMD_EXT_TEMP,
+	},
+	[CIN1] = {
+		.addr = AD7746_REG_CAP_DATA_HIGH,
+	},
+	[CIN1_DIFF] = {
+		.addr =  AD7746_REG_CAP_DATA_HIGH,
+		.capdiff = 1,
+	},
+	[CIN2] = {
+		.addr = AD7746_REG_CAP_DATA_HIGH,
+		.cin2 = 1,
+	},
+	[CIN2_DIFF] = {
+		.addr = AD7746_REG_CAP_DATA_HIGH,
+		.cin2 = 1,
+		.capdiff = 1,
+	},
+};
+
 static const struct iio_chan_spec ad7746_channels[] = {
 	[VIN] = {
 		.type = IIO_VOLTAGE,
@@ -116,8 +163,7 @@ static const struct iio_chan_spec ad7746_channels[] = {
 		.channel = 0,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ),
-		.address = AD7746_REG_VT_DATA_HIGH << 8 |
-			AD7746_VTSETUP_VTMD_EXT_VIN,
+		.address = VIN,
 	},
 	[VIN_VDD] = {
 		.type = IIO_VOLTAGE,
@@ -126,24 +172,21 @@ static const struct iio_chan_spec ad7746_channels[] = {
 		.extend_name = "supply",
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ),
-		.address = AD7746_REG_VT_DATA_HIGH << 8 |
-			AD7746_VTSETUP_VTMD_VDD_MON,
+		.address = VIN_VDD,
 	},
 	[TEMP_INT] = {
 		.type = IIO_TEMP,
 		.indexed = 1,
 		.channel = 0,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
-		.address = AD7746_REG_VT_DATA_HIGH << 8 |
-			AD7746_VTSETUP_VTMD_INT_TEMP,
+		.address = TEMP_INT,
 	},
 	[TEMP_EXT] = {
 		.type = IIO_TEMP,
 		.indexed = 1,
 		.channel = 1,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
-		.address = AD7746_REG_VT_DATA_HIGH << 8 |
-			AD7746_VTSETUP_VTMD_EXT_TEMP,
+		.address = TEMP_EXT,
 	},
 	[CIN1] = {
 		.type = IIO_CAPACITANCE,
@@ -153,7 +196,7 @@ static const struct iio_chan_spec ad7746_channels[] = {
 		BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_OFFSET),
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
 		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
-		.address = AD7746_REG_CAP_DATA_HIGH << 8,
+		.address = CIN1,
 	},
 	[CIN1_DIFF] = {
 		.type = IIO_CAPACITANCE,
@@ -165,8 +208,7 @@ static const struct iio_chan_spec ad7746_channels[] = {
 		BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_OFFSET),
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
 		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
-		.address = AD7746_REG_CAP_DATA_HIGH << 8 |
-			AD7746_CAPSETUP_CAPDIFF
+		.address = CIN1_DIFF,
 	},
 	[CIN2] = {
 		.type = IIO_CAPACITANCE,
@@ -176,8 +218,7 @@ static const struct iio_chan_spec ad7746_channels[] = {
 		BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_OFFSET),
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
 		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
-		.address = AD7746_REG_CAP_DATA_HIGH << 8 |
-			AD7746_CAPSETUP_CIN2,
+		.address = CIN2,
 	},
 	[CIN2_DIFF] = {
 		.type = IIO_CAPACITANCE,
@@ -189,8 +230,7 @@ static const struct iio_chan_spec ad7746_channels[] = {
 		BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_OFFSET),
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
 		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
-		.address = AD7746_REG_CAP_DATA_HIGH << 8 |
-			AD7746_CAPSETUP_CAPDIFF | AD7746_CAPSETUP_CIN2,
+		.address = CIN2_DIFF,
 	}
 };
 
@@ -226,10 +266,13 @@ static int ad7746_select_channel(struct iio_dev *indio_dev,
 
 	switch (chan->type) {
 	case IIO_CAPACITANCE:
-		cap_setup = (chan->address & 0xFF) | AD7746_CAPSETUP_CAPEN;
+		cap_setup = FIELD_PREP(AD7746_CAPSETUP_CIN2,
+				       ad7746_chan_info[chan->address].cin2) |
+			FIELD_PREP(AD7746_CAPSETUP_CAPDIFF,
+				   ad7746_chan_info[chan->address].capdiff) |
+			FIELD_PREP(AD7746_CAPSETUP_CAPEN, 1);
 		vt_setup = chip->vt_setup & ~AD7746_VTSETUP_VTEN;
-		idx = (chip->config & AD7746_CONF_CAPFS_MASK) >>
-			AD7746_CONF_CAPFS_SHIFT;
+		idx = FIELD_GET(AD7746_CONF_CAPFS_MASK, chip->config);
 		delay = ad7746_cap_filter_rate_table[idx][1];
 
 		ret = ad7746_set_capdac(chip, chan->channel);
@@ -241,10 +284,11 @@ static int ad7746_select_channel(struct iio_dev *indio_dev,
 		break;
 	case IIO_VOLTAGE:
 	case IIO_TEMP:
-		vt_setup = (chan->address & 0xFF) | AD7746_VTSETUP_VTEN;
+		vt_setup = FIELD_PREP(AD7746_VTSETUP_VTMD_MASK,
+				      ad7746_chan_info[chan->address].vtmd) |
+			FIELD_PREP(AD7746_VTSETUP_VTEN, 1);
 		cap_setup = chip->cap_setup & ~AD7746_CAPSETUP_CAPEN;
-		idx = (chip->config & AD7746_CONF_VTFS_MASK) >>
-			AD7746_CONF_VTFS_SHIFT;
+		idx = FIELD_GET(AD7746_CONF_VTFS_MASK, chip->config);
 		delay = ad7746_cap_filter_rate_table[idx][1];
 		break;
 	default:
@@ -327,7 +371,8 @@ static ssize_t ad7746_start_offset_calib(struct device *dev,
 		return ret;
 
 	return ad7746_start_calib(dev, attr, buf, len,
-				  AD7746_CONF_MODE_OFFS_CAL);
+				  FIELD_PREP(AD7746_CONF_MODE_MASK,
+					     AD7746_CONF_MODE_OFFS_CAL));
 }
 
 static ssize_t ad7746_start_gain_calib(struct device *dev,
@@ -342,7 +387,8 @@ static ssize_t ad7746_start_gain_calib(struct device *dev,
 		return ret;
 
 	return ad7746_start_calib(dev, attr, buf, len,
-				  AD7746_CONF_MODE_GAIN_CAL);
+				  FIELD_PREP(AD7746_CONF_MODE_MASK,
+					     AD7746_CONF_MODE_GAIN_CAL));
 }
 
 static IIO_DEVICE_ATTR(in_capacitance0_calibbias_calibration,
@@ -369,7 +415,7 @@ static int ad7746_store_cap_filter_rate_setup(struct ad7746_chip_info *chip,
 		i = ARRAY_SIZE(ad7746_cap_filter_rate_table) - 1;
 
 	chip->config &= ~AD7746_CONF_CAPFS_MASK;
-	chip->config |= i << AD7746_CONF_CAPFS_SHIFT;
+	chip->config |= FIELD_PREP(AD7746_CONF_CAPFS_MASK, i);
 
 	return 0;
 }
@@ -387,7 +433,7 @@ static int ad7746_store_vt_filter_rate_setup(struct ad7746_chip_info *chip,
 		i = ARRAY_SIZE(ad7746_vt_filter_rate_table) - 1;
 
 	chip->config &= ~AD7746_CONF_VTFS_MASK;
-	chip->config |= i << AD7746_CONF_VTFS_SHIFT;
+	chip->config |= FIELD_PREP(AD7746_CONF_VTFS_MASK, i);
 
 	return 0;
 }
@@ -470,7 +516,7 @@ static int ad7746_write_raw(struct iio_dev *indio_dev,
 		val /= 338646;
 		mutex_lock(&chip->lock);
 		chip->capdac[chan->channel][chan->differential] = val > 0 ?
-			AD7746_CAPDAC_DACP(val) | AD7746_CAPDAC_DACEN : 0;
+			FIELD_PREP(AD7746_CAPDAC_DACP_MASK, val) | AD7746_CAPDAC_DACEN : 0;
 
 		ret = ad7746_set_capdac(chip, chan->channel);
 		if (ret < 0) {
@@ -519,14 +565,16 @@ static int ad7746_read_channel(struct iio_dev *indio_dev,
 		return ret;
 	delay = ret;
 
-	regval = chip->config | AD7746_CONF_MODE_SINGLE_CONV;
+	regval = chip->config | FIELD_PREP(AD7746_CONF_MODE_MASK,
+					   AD7746_CONF_MODE_SINGLE_CONV);
 	ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG, regval);
 	if (ret < 0)
 		return ret;
 
 	msleep(delay);
 	/* Now read the actual register */
-	ret = i2c_smbus_read_i2c_block_data(chip->client,  chan->address >> 8,
+	ret = i2c_smbus_read_i2c_block_data(chip->client,
+					    ad7746_chan_info[chan->address].addr,
 					    sizeof(data), data);
 	if (ret < 0)
 		return ret;
@@ -600,8 +648,8 @@ static int ad7746_read_raw(struct iio_dev *indio_dev,
 
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_OFFSET:
-		*val = AD7746_CAPDAC_DACP(chip->capdac[chan->channel]
-					  [chan->differential]) * 338646;
+		*val = FIELD_GET(AD7746_CAPDAC_DACP_MASK,
+				 chip->capdac[chan->channel][chan->differential]) * 338646;
 
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
@@ -624,13 +672,11 @@ static int ad7746_read_raw(struct iio_dev *indio_dev,
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		switch (chan->type) {
 		case IIO_CAPACITANCE:
-			idx = (chip->config & AD7746_CONF_CAPFS_MASK) >>
-				AD7746_CONF_CAPFS_SHIFT;
+			idx = FIELD_GET(AD7746_CONF_CAPFS_MASK, chip->config);
 			*val = ad7746_cap_filter_rate_table[idx][0];
 			return IIO_VAL_INT;
 		case IIO_VOLTAGE:
-			idx = (chip->config & AD7746_CONF_VTFS_MASK) >>
-				AD7746_CONF_VTFS_SHIFT;
+			idx = FIELD_GET(AD7746_CONF_VTFS_MASK, chip->config);
 			*val = ad7746_vt_filter_rate_table[idx][0];
 			return IIO_VAL_INT;
 		default:
@@ -696,16 +742,16 @@ static int ad7746_probe(struct i2c_client *client,
 	if (!ret) {
 		switch (vdd_permille) {
 		case 125:
-			regval |= AD7746_EXCSETUP_EXCLVL(0);
+			regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 0);
 			break;
 		case 250:
-			regval |= AD7746_EXCSETUP_EXCLVL(1);
+			regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 1);
 			break;
 		case 375:
-			regval |= AD7746_EXCSETUP_EXCLVL(2);
+			regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 2);
 			break;
 		case 500:
-			regval |= AD7746_EXCSETUP_EXCLVL(3);
+			regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 3);
 			break;
 		default:
 			break;