[PATCH v2] iio: frequency: ad9832: Use FIELD_PREP macro to set bit fields

[Siddharth Menon <simeddon@gmail.com>]

Refactor code to use the FIELD_PREP macro for setting bit fields
instead of manual bit manipulation.

Suggested-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Signed-off-by: Siddharth Menon <simeddon@gmail.com>
---
 Based on feedback from Jonathan and Marcello, I have made the following
 changes
 
 v1->v2:
 - removed CMD_SHIFT andADD_SHIFT completely
 - use GENMASK
 - store regval into an array and iterate through it
 drivers/staging/iio/frequency/ad9832.c | 53 ++++++++++++++------------
 1 file changed, 28 insertions(+), 25 deletions(-)

diff --git a/drivers/staging/iio/frequency/ad9832.c b/drivers/staging/iio/frequency/ad9832.c
index 140ee4f9c137..0c1816505495 100644
--- a/drivers/staging/iio/frequency/ad9832.c
+++ b/drivers/staging/iio/frequency/ad9832.c
@@ -16,6 +16,8 @@
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
 #include <linux/sysfs.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -65,11 +67,12 @@
 #define AD9832_SLEEP		BIT(13)
 #define AD9832_RESET		BIT(12)
 #define AD9832_CLR		BIT(11)
-#define CMD_SHIFT		12
-#define ADD_SHIFT		8
 #define AD9832_FREQ_BITS	32
 #define AD9832_PHASE_BITS	12
 #define RES_MASK(bits)		((1 << (bits)) - 1)
+#define CMD_MASK_2   GENMASK(15, 12)
+#define ADD_MASK_2   GENMASK(11, 8)
+#define DATA_MASK_2  GENMASK(7, 0)
 
 /**
  * struct ad9832_state - driver instance specific data
@@ -131,6 +134,7 @@ static int ad9832_write_frequency(struct ad9832_state *st,
 {
 	unsigned long clk_freq;
 	unsigned long regval;
+	u8 regval_bytes[4];
 
 	clk_freq = clk_get_rate(st->mclk);
 
@@ -138,19 +142,14 @@ static int ad9832_write_frequency(struct ad9832_state *st,
 		return -EINVAL;
 
 	regval = ad9832_calc_freqreg(clk_freq, fout);
+	put_unaligned_be32(regval, regval_bytes);
 
-	st->freq_data[0] = cpu_to_be16((AD9832_CMD_FRE8BITSW << CMD_SHIFT) |
-					(addr << ADD_SHIFT) |
-					((regval >> 24) & 0xFF));
-	st->freq_data[1] = cpu_to_be16((AD9832_CMD_FRE16BITSW << CMD_SHIFT) |
-					((addr - 1) << ADD_SHIFT) |
-					((regval >> 16) & 0xFF));
-	st->freq_data[2] = cpu_to_be16((AD9832_CMD_FRE8BITSW << CMD_SHIFT) |
-					((addr - 2) << ADD_SHIFT) |
-					((regval >> 8) & 0xFF));
-	st->freq_data[3] = cpu_to_be16((AD9832_CMD_FRE16BITSW << CMD_SHIFT) |
-					((addr - 3) << ADD_SHIFT) |
-					((regval >> 0) & 0xFF));
+	for (int i = 0; i < 4; i++) {
+		st->freq_data[i] = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK,
+				(i % 2 == 0) ? AD9832_CMD_FRE8BITSW : AD9832_CMD_FRE16BITSW) |
+			FIELD_PREP(AD9832_ADD_MSK, addr - i) |
+			FIELD_PREP(AD9832_DAT_MSK, regval_bytes[i]));
+	}
 
 	return spi_sync(st->spi, &st->freq_msg);
 }
@@ -158,15 +157,19 @@ static int ad9832_write_frequency(struct ad9832_state *st,
 static int ad9832_write_phase(struct ad9832_state *st,
 			      unsigned long addr, unsigned long phase)
 {
+	u8 phase_bytes[2];
+
 	if (phase >= BIT(AD9832_PHASE_BITS))
 		return -EINVAL;
 
-	st->phase_data[0] = cpu_to_be16((AD9832_CMD_PHA8BITSW << CMD_SHIFT) |
-					(addr << ADD_SHIFT) |
-					((phase >> 8) & 0xFF));
-	st->phase_data[1] = cpu_to_be16((AD9832_CMD_PHA16BITSW << CMD_SHIFT) |
-					((addr - 1) << ADD_SHIFT) |
-					(phase & 0xFF));
+	put_unaligned_be16(phase, phase_bytes);
+
+	for (int i = 0; i < 2; i++) {
+		st->phase_data[i] = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK,
+				(i % 2 == 0) ? AD9832_CMD_PHA8BITSW : AD9832_CMD_PHA16BITSW) |
+			FIELD_PREP(AD9832_ADD_MSK, addr - i) |
+			FIELD_PREP(AD9832_DAT_MSK, phase_bytes[i]));
+	}
 
 	return spi_sync(st->spi, &st->phase_msg);
 }
@@ -201,7 +204,7 @@ static ssize_t ad9832_write(struct device *dev, struct device_attribute *attr,
 			st->ctrl_ss &= ~AD9832_SELSRC;
 		else
 			st->ctrl_ss |= AD9832_SELSRC;
-		st->data = cpu_to_be16((AD9832_CMD_SYNCSELSRC << CMD_SHIFT) |
+		st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_SYNCSELSRC) |
 					st->ctrl_ss);
 		ret = spi_sync(st->spi, &st->msg);
 		break;
@@ -214,7 +217,7 @@ static ssize_t ad9832_write(struct device *dev, struct device_attribute *attr,
 			ret = -EINVAL;
 			break;
 		}
-		st->data = cpu_to_be16((AD9832_CMD_FPSELECT << CMD_SHIFT) |
+		st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_FPSELECT) |
 					st->ctrl_fp);
 		ret = spi_sync(st->spi, &st->msg);
 		break;
@@ -227,7 +230,7 @@ static ssize_t ad9832_write(struct device *dev, struct device_attribute *attr,
 		st->ctrl_fp &= ~AD9832_PHASE(3);
 		st->ctrl_fp |= AD9832_PHASE(val);
 
-		st->data = cpu_to_be16((AD9832_CMD_FPSELECT << CMD_SHIFT) |
+		st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_FPSELECT) |
 					st->ctrl_fp);
 		ret = spi_sync(st->spi, &st->msg);
 		break;
@@ -238,7 +241,7 @@ static ssize_t ad9832_write(struct device *dev, struct device_attribute *attr,
 		else
 			st->ctrl_src |= AD9832_RESET;
 
-		st->data = cpu_to_be16((AD9832_CMD_SLEEPRESCLR << CMD_SHIFT) |
+		st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_SLEEPRESCLR) |
 					st->ctrl_src);
 		ret = spi_sync(st->spi, &st->msg);
 		break;
@@ -396,7 +399,7 @@ static int ad9832_probe(struct spi_device *spi)
 	spi_message_add_tail(&st->phase_xfer[1], &st->phase_msg);
 
 	st->ctrl_src = AD9832_SLEEP | AD9832_RESET | AD9832_CLR;
-	st->data = cpu_to_be16((AD9832_CMD_SLEEPRESCLR << CMD_SHIFT) |
+	st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_SLEEPRESCLR) |
 					st->ctrl_src);
 	ret = spi_sync(st->spi, &st->msg);
 	if (ret) {
-- 
2.48.1