iio: accel: kxsd9: Convert to use regmap for transport

This converts the KXSD9 driver to drop the custom transport
mechanism and just use regmap like everything else.
Tested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/accel/Kconfig

@@ -131,6 +131,7 @@ config KXSD9_SPI
 	depends on KXSD9
 	depends on SPI
 	default KXSD9
+	select REGMAP_SPI
 	help
 	  Say yes here to enable the Kionix KXSD9 accelerometer
 	  SPI transport channel.

drivers/iio/accel/kxsd9-spi.c

@@ -3,75 +3,30 @@
 #include <linux/spi/spi.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/regmap.h>
 
 #include "kxsd9.h"
 
-#define KXSD9_READ(a) (0x80 | (a))
-#define KXSD9_WRITE(a) (a)
-
-static int kxsd9_spi_readreg(struct kxsd9_transport *tr, u8 address)
-{
-	struct spi_device *spi = tr->trdev;
-
-	return spi_w8r8(spi, KXSD9_READ(address));
-}
-
-static int kxsd9_spi_writereg(struct kxsd9_transport *tr, u8 address, u8 val)
-{
-	struct spi_device *spi = tr->trdev;
-
-	tr->tx[0] = KXSD9_WRITE(address),
-	tr->tx[1] = val;
-	return spi_write(spi, tr->tx, 2);
-}
-
-static int kxsd9_spi_readval(struct kxsd9_transport *tr, u8 address)
-{
-	struct spi_device *spi = tr->trdev;
-	struct spi_transfer xfers[] = {
-		{
-			.bits_per_word = 8,
-			.len = 1,
-			.delay_usecs = 200,
-			.tx_buf = tr->tx,
-		}, {
-			.bits_per_word = 8,
-			.len = 2,
-			.rx_buf = tr->rx,
-		},
-	};
-	int ret;
-
-	tr->tx[0] = KXSD9_READ(address);
-	ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));
-	if (!ret)
-		ret = (((u16)(tr->rx[0])) << 8) | (tr->rx[1]);
-	return ret;
-}
-
 static int kxsd9_spi_probe(struct spi_device *spi)
 {
-	struct kxsd9_transport *transport;
-	int ret;
-
-	transport = devm_kzalloc(&spi->dev, sizeof(*transport), GFP_KERNEL);
-	if (!transport)
-		return -ENOMEM;
+	static const struct regmap_config config = {
+		.reg_bits = 8,
+		.val_bits = 8,
+		.max_register = 0x0e,
+	};
+	struct regmap *regmap;
 
-	transport->trdev = spi;
-	transport->readreg = kxsd9_spi_readreg;
-	transport->writereg = kxsd9_spi_writereg;
-	transport->readval = kxsd9_spi_readval;
 	spi->mode = SPI_MODE_0;
-	spi_setup(spi);
-
-	ret = kxsd9_common_probe(&spi->dev,
-				 transport,
+	regmap = devm_regmap_init_spi(spi, &config);
+	if (IS_ERR(regmap)) {
+		dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
+			__func__, PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	return kxsd9_common_probe(&spi->dev,
+				  regmap,
 				  spi_get_device_id(spi)->name);
-	if (ret)
-		return ret;
-
-	return 0;
 }
 
 static int kxsd9_spi_remove(struct spi_device *spi)

drivers/iio/accel/kxsd9.c

@@ -21,7 +21,7 @@
 #include <linux/sysfs.h>
 #include <linux/slab.h>
 #include <linux/module.h>
-
+#include <linux/regmap.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 
@@ -46,7 +46,7 @@
  * @us:		spi device
  **/
 struct kxsd9_state {
-	struct kxsd9_transport *transport;
+	struct regmap *map;
 	struct mutex buf_lock;
 };
 
@@ -63,6 +63,7 @@ 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]) {
@@ -73,13 +74,14 @@ static int kxsd9_write_scale(struct iio_dev *indio_dev, int micro)
 		return -EINVAL;
 
 	mutex_lock(&st->buf_lock);
-	ret = st->transport->readreg(st->transport,
-				     KXSD9_REG_CTRL_C);
+	ret = regmap_read(st->map,
+			  KXSD9_REG_CTRL_C,
+			  &val);
 	if (ret < 0)
 		goto error_ret;
-	ret = st->transport->writereg(st->transport,
+	ret = regmap_write(st->map,
 			   KXSD9_REG_CTRL_C,
-				      (ret & ~KXSD9_FS_MASK) | i);
+			   (val & ~KXSD9_FS_MASK) | i);
 error_ret:
 	mutex_unlock(&st->buf_lock);
 	return ret;
@@ -89,11 +91,15 @@ static int kxsd9_read(struct iio_dev *indio_dev, u8 address)
 {
 	int ret;
 	struct kxsd9_state *st = iio_priv(indio_dev);
+	__be16 raw_val;
 
 	mutex_lock(&st->buf_lock);
-	ret = st->transport->readval(st->transport, address);
+	ret = regmap_bulk_read(st->map, address, &raw_val, sizeof(raw_val));
+	if (ret)
+		goto out_fail_read;
 	/* Only 12 bits are valid */
-	ret &= 0xfff0;
+	ret = be16_to_cpu(raw_val) & 0xfff0;
+out_fail_read:
 	mutex_unlock(&st->buf_lock);
 	return ret;
 }
@@ -133,6 +139,7 @@ static int kxsd9_read_raw(struct iio_dev *indio_dev,
 {
 	int ret = -EINVAL;
 	struct kxsd9_state *st = iio_priv(indio_dev);
+	unsigned int regval;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
@@ -143,12 +150,13 @@ static int kxsd9_read_raw(struct iio_dev *indio_dev,
 		ret = IIO_VAL_INT;
 		break;
 	case IIO_CHAN_INFO_SCALE:
-		ret = st->transport->readreg(st->transport,
-					     KXSD9_REG_CTRL_C);
+		ret = regmap_read(st->map,
+				  KXSD9_REG_CTRL_C,
+				  &regval);
 		if (ret < 0)
 			goto error_ret;
 		*val = 0;
-		*val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK];
+		*val2 = kxsd9_micro_scales[regval & KXSD9_FS_MASK];
 		ret = IIO_VAL_INT_PLUS_MICRO;
 		break;
 	}
@@ -184,10 +192,10 @@ static int kxsd9_power_up(struct kxsd9_state *st)
 {
 	int ret;
 
-	ret = st->transport->writereg(st->transport, KXSD9_REG_CTRL_B, 0x40);
+	ret = regmap_write(st->map, KXSD9_REG_CTRL_B, 0x40);
 	if (ret)
 		return ret;
-	return st->transport->writereg(st->transport, KXSD9_REG_CTRL_C, 0x9b);
+	return regmap_write(st->map, KXSD9_REG_CTRL_C, 0x9b);
 };
 
 static const struct iio_info kxsd9_info = {
@@ -198,7 +206,7 @@ static const struct iio_info kxsd9_info = {
 };
 
 int kxsd9_common_probe(struct device *parent,
-		       struct kxsd9_transport *transport,
+		       struct regmap *map,
 		       const char *name)
 {
 	struct iio_dev *indio_dev;
@@ -210,7 +218,7 @@ int kxsd9_common_probe(struct device *parent,
 		return -ENOMEM;
 
 	st = iio_priv(indio_dev);
-	st->transport = transport;
+	st->map = map;
 
 	mutex_init(&st->buf_lock);
 	indio_dev->channels = kxsd9_channels;

drivers/iio/accel/kxsd9.h

@@ -4,27 +4,7 @@
 #define KXSD9_STATE_RX_SIZE 2
 #define KXSD9_STATE_TX_SIZE 2
 
-struct kxsd9_transport;
-
-/**
- * struct kxsd9_transport - transport adapter for SPI or I2C
- * @trdev: transport device such as SPI or I2C
- * @readreg(): function to read a byte from an address in the device
- * @writereg(): function to write a byte to an address in the device
- * @readval(): function to read a 16bit value from the device
- * @rx: cache aligned read buffer
- * @tx: cache aligned write buffer
- */
-struct kxsd9_transport {
-	void *trdev;
-	int (*readreg) (struct kxsd9_transport *tr, u8 address);
-	int (*writereg) (struct kxsd9_transport *tr, u8 address, u8 val);
-	int (*readval) (struct kxsd9_transport *tr, u8 address);
-	u8 rx[KXSD9_STATE_RX_SIZE] ____cacheline_aligned;
-	u8 tx[KXSD9_STATE_TX_SIZE];
-};
-
 int kxsd9_common_probe(struct device *parent,
-		       struct kxsd9_transport *transport,
+		       struct regmap *map,
 		       const char *name);
 int kxsd9_common_remove(struct device *parent);