iio: accel: kxsd9: Deploy proper register bit defines

There are some hardcoded register values etc in the code, define
proper bitfield definitions, and use them when getting and setting
the scale. Optimize a read/modify/write to use regmap_update_bits()
at the same time.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/accel/kxsd9.c

@@ -20,6 +20,7 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
+#include <linux/bitops.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/buffer.h>
@@ -35,9 +36,29 @@
 #define KXSD9_REG_RESET		0x0a
 #define KXSD9_REG_CTRL_C	0x0c
 
-#define KXSD9_FS_MASK		0x03
+#define KXSD9_CTRL_C_FS_MASK	0x03
+#define KXSD9_CTRL_C_FS_8G	0x00
+#define KXSD9_CTRL_C_FS_6G	0x01
+#define KXSD9_CTRL_C_FS_4G	0x02
+#define KXSD9_CTRL_C_FS_2G	0x03
+#define KXSD9_CTRL_C_MOT_LAT	BIT(3)
+#define KXSD9_CTRL_C_MOT_LEV	BIT(4)
+#define KXSD9_CTRL_C_LP_MASK	0xe0
+#define KXSD9_CTRL_C_LP_NONE	0x00
+#define KXSD9_CTRL_C_LP_2000HZC	BIT(5)
+#define KXSD9_CTRL_C_LP_2000HZB	BIT(6)
+#define KXSD9_CTRL_C_LP_2000HZA	(BIT(5)|BIT(6))
+#define KXSD9_CTRL_C_LP_1000HZ	BIT(7)
+#define KXSD9_CTRL_C_LP_500HZ	(BIT(7)|BIT(5))
+#define KXSD9_CTRL_C_LP_100HZ	(BIT(7)|BIT(6))
+#define KXSD9_CTRL_C_LP_50HZ	(BIT(7)|BIT(6)|BIT(5))
 
 #define KXSD9_REG_CTRL_B	0x0d
+
+#define KXSD9_CTRL_B_CLK_HLD	BIT(7)
+#define KXSD9_CTRL_B_ENABLE	BIT(6)
+#define KXSD9_CTRL_B_ST		BIT(5) /* Self-test */
+
 #define KXSD9_REG_CTRL_A	0x0e
 
 /**
@@ -65,7 +86,6 @@ static int kxsd9_write_scale(struct iio_dev *indio_dev, int micro)
 	int ret, i;
 	struct kxsd9_state *st = iio_priv(indio_dev);
 	bool foundit = false;
-	unsigned int val;
 
 	for (i = 0; i < 4; i++)
 		if (micro == kxsd9_micro_scales[i]) {
@@ -75,14 +95,12 @@ static int kxsd9_write_scale(struct iio_dev *indio_dev, int micro)
 	if (!foundit)
 		return -EINVAL;
 
-	ret = regmap_read(st->map,
+	ret = regmap_update_bits(st->map,
 				 KXSD9_REG_CTRL_C,
-			  &val);
+				 KXSD9_CTRL_C_FS_MASK,
+				 i);
 	if (ret < 0)
 		goto error_ret;
-	ret = regmap_write(st->map,
-			   KXSD9_REG_CTRL_C,
-			   (val & ~KXSD9_FS_MASK) | i);
 error_ret:
 	return ret;
 }
@@ -150,7 +168,7 @@ static int kxsd9_read_raw(struct iio_dev *indio_dev,
 		if (ret < 0)
 			goto error_ret;
 		*val = 0;
-		*val2 = kxsd9_micro_scales[regval & KXSD9_FS_MASK];
+		*val2 = kxsd9_micro_scales[regval & KXSD9_CTRL_C_FS_MASK];
 		ret = IIO_VAL_INT_PLUS_MICRO;
 		break;
 	}