staging:iio:hmc5843: Added regmap support

This patch changes hmc5843.c to use regmap. This provides transparent caching
to the code as well as abstraction necessary to add support for SPI-based
hmc5983.
Signed-off-by: Josef Gajdusek <atx@atx.name>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/magnetometer/Kconfig

@@ -8,6 +8,7 @@ config SENSORS_HMC5843
 	depends on I2C
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
+	select REGMAP_I2C
 	help
 	  Say Y here to add support for the Honeywell HMC5843, HMC5883 and
 	  HMC5883L 3-Axis Magnetometer (digital compass).

drivers/staging/iio/magnetometer/hmc5843.c

@@ -21,6 +21,7 @@
 
 #include <linux/module.h>
 #include <linux/i2c.h>
+#include <linux/regmap.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/trigger_consumer.h>
@@ -34,6 +35,7 @@
 #define HMC5843_DATA_OUT_MSB_REGS		0x03
 #define HMC5843_STATUS_REG			0x09
 #define HMC5843_ID_REG				0x0a
+#define HMC5843_ID_END				0x0c
 
 enum hmc5843_ids {
 	HMC5843_ID,
@@ -49,6 +51,7 @@ enum hmc5843_ids {
 #define HMC5843_RANGE_GAIN_OFFSET		0x05
 #define HMC5843_RANGE_GAIN_DEFAULT		0x01
 #define HMC5843_RANGE_GAINS			8
+#define HMC5843_RANGE_GAIN_MASK		0xe0
 
 /* Device status */
 #define HMC5843_DATA_READY			0x01
@@ -68,6 +71,7 @@ enum hmc5843_ids {
 #define HMC5843_RATE_OFFSET			0x02
 #define HMC5843_RATE_DEFAULT			0x04
 #define HMC5843_RATES				7
+#define HMC5843_RATE_MASK		0x1c
 
 /* Device measurement configuration */
 #define HMC5843_MEAS_CONF_NORMAL		0x00
@@ -121,10 +125,7 @@ struct hmc5843_chip_info {
 struct hmc5843_data {
 	struct i2c_client *client;
 	struct mutex lock;
-	u8 rate;
-	u8 meas_conf;
-	u8 operating_mode;
-	u8 range;
+	struct regmap *regmap;
 	const struct hmc5843_chip_info *variant;
 	__be16 buffer[8]; /* 3x 16-bit channels + padding + 64-bit timestamp */
 };
@@ -135,10 +136,8 @@ static s32 hmc5843_set_mode(struct hmc5843_data *data, u8 operating_mode)
 	int ret;
 
 	mutex_lock(&data->lock);
-	ret = i2c_smbus_write_byte_data(data->client, HMC5843_MODE_REG,
-					operating_mode & HMC5843_MODE_MASK);
-	if (ret >= 0)
-		data->operating_mode = operating_mode;
+	ret = regmap_update_bits(data->regmap, HMC5843_MODE_REG,
+			HMC5843_MODE_MASK, operating_mode);
 	mutex_unlock(&data->lock);
 
 	return ret;
@@ -146,15 +145,15 @@ static s32 hmc5843_set_mode(struct hmc5843_data *data, u8 operating_mode)
 
 static int hmc5843_wait_measurement(struct hmc5843_data *data)
 {
-	s32 result;
 	int tries = 150;
+	int val;
+	int ret;
 
 	while (tries-- > 0) {
-		result = i2c_smbus_read_byte_data(data->client,
-			HMC5843_STATUS_REG);
-		if (result < 0)
-			return result;
-		if (result & HMC5843_DATA_READY)
+		ret = regmap_read(data->regmap, HMC5843_STATUS_REG, &val);
+		if (ret < 0)
+			return ret;
+		if (val & HMC5843_DATA_READY)
 			break;
 		msleep(20);
 	}
@@ -171,20 +170,20 @@ static int hmc5843_wait_measurement(struct hmc5843_data *data)
 static int hmc5843_read_measurement(struct hmc5843_data *data,
 				    int idx, int *val)
 {
-	s32 result;
 	__be16 values[3];
+	int ret;
 
 	mutex_lock(&data->lock);
-	result = hmc5843_wait_measurement(data);
-	if (result < 0) {
+	ret = hmc5843_wait_measurement(data);
+	if (ret < 0) {
 		mutex_unlock(&data->lock);
-		return result;
+		return ret;
 	}
-	result = i2c_smbus_read_i2c_block_data(data->client,
-		HMC5843_DATA_OUT_MSB_REGS, sizeof(values), (u8 *) values);
+	ret = regmap_bulk_read(data->regmap, HMC5843_DATA_OUT_MSB_REGS,
+			values, sizeof(values));
 	mutex_unlock(&data->lock);
-	if (result < 0)
-		return -EINVAL;
+	if (ret < 0)
+		return ret;
 
 	*val = sign_extend32(be16_to_cpu(values[idx]), 15);
 	return IIO_VAL_INT;
@@ -208,16 +207,13 @@ static int hmc5843_read_measurement(struct hmc5843_data *data,
  *     and BN.
  *
  */
-static s32 hmc5843_set_meas_conf(struct hmc5843_data *data, u8 meas_conf)
+static int hmc5843_set_meas_conf(struct hmc5843_data *data, u8 meas_conf)
 {
 	int ret;
 
 	mutex_lock(&data->lock);
-	ret = i2c_smbus_write_byte_data(data->client, HMC5843_CONFIG_REG_A,
-		(meas_conf & HMC5843_MEAS_CONF_MASK) |
-		(data->rate << HMC5843_RATE_OFFSET));
-	if (ret >= 0)
-		data->meas_conf = meas_conf;
+	ret = regmap_update_bits(data->regmap, HMC5843_CONFIG_REG_A,
+			HMC5843_MEAS_CONF_MASK, meas_conf);
 	mutex_unlock(&data->lock);
 
 	return ret;
@@ -228,7 +224,15 @@ static ssize_t hmc5843_show_measurement_configuration(struct device *dev,
 						char *buf)
 {
 	struct hmc5843_data *data = iio_priv(dev_to_iio_dev(dev));
-	return sprintf(buf, "%d\n", data->meas_conf);
+	int val;
+	int ret;
+
+	ret = regmap_read(data->regmap, HMC5843_CONFIG_REG_A, &val);
+	if (ret)
+		return ret;
+	val &= HMC5843_MEAS_CONF_MASK;
+
+	return sprintf(buf, "%d\n", val);
 }
 
 static ssize_t hmc5843_set_measurement_configuration(struct device *dev,
@@ -282,10 +286,8 @@ static int hmc5843_set_samp_freq(struct hmc5843_data *data, u8 rate)
 	int ret;
 
 	mutex_lock(&data->lock);
-	ret = i2c_smbus_write_byte_data(data->client, HMC5843_CONFIG_REG_A,
-		data->meas_conf | (rate << HMC5843_RATE_OFFSET));
-	if (ret >= 0)
-		data->rate = rate;
+	ret = regmap_update_bits(data->regmap, HMC5843_CONFIG_REG_A,
+			HMC5843_RATE_MASK, rate << HMC5843_RATE_OFFSET);
 	mutex_unlock(&data->lock);
 
 	return ret;
@@ -309,10 +311,9 @@ static int hmc5843_set_range_gain(struct hmc5843_data *data, u8 range)
 	int ret;
 
 	mutex_lock(&data->lock);
-	ret = i2c_smbus_write_byte_data(data->client, HMC5843_CONFIG_REG_B,
+	ret = regmap_update_bits(data->regmap, HMC5843_CONFIG_REG_B,
+			HMC5843_RANGE_GAIN_MASK,
 			range << HMC5843_RANGE_GAIN_OFFSET);
-	if (ret >= 0)
-		data->range = range;
 	mutex_unlock(&data->lock);
 
 	return ret;
@@ -358,17 +359,27 @@ static int hmc5843_read_raw(struct iio_dev *indio_dev,
 			    int *val, int *val2, long mask)
 {
 	struct hmc5843_data *data = iio_priv(indio_dev);
+	int rval;
+	int ret;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		return hmc5843_read_measurement(data, chan->scan_index, val);
 	case IIO_CHAN_INFO_SCALE:
+		ret = regmap_read(data->regmap, HMC5843_CONFIG_REG_B, &rval);
+		if (ret < 0)
+			return ret;
+		rval >>= HMC5843_RANGE_GAIN_OFFSET;
 		*val = 0;
-		*val2 = data->variant->regval_to_nanoscale[data->range];
+		*val2 = data->variant->regval_to_nanoscale[rval];
 		return IIO_VAL_INT_PLUS_NANO;
 	case IIO_CHAN_INFO_SAMP_FREQ:
-		*val = data->variant->regval_to_samp_freq[data->rate][0];
-		*val2 = data->variant->regval_to_samp_freq[data->rate][1];
+		ret = regmap_read(data->regmap, HMC5843_CONFIG_REG_A, &rval);
+		if (ret < 0)
+			return ret;
+		rval >>= HMC5843_RATE_OFFSET;
+		*val = data->variant->regval_to_samp_freq[rval][0];
+		*val2 = data->variant->regval_to_samp_freq[rval][1];
 		return IIO_VAL_INT_PLUS_MICRO;
 	}
 	return -EINVAL;
@@ -426,9 +437,9 @@ static irqreturn_t hmc5843_trigger_handler(int irq, void *p)
 		goto done;
 	}
 
-	ret = i2c_smbus_read_i2c_block_data(data->client,
-		HMC5843_DATA_OUT_MSB_REGS, 3 * sizeof(__be16),
-			(u8 *) data->buffer);
+	ret = regmap_bulk_read(data->regmap, HMC5843_DATA_OUT_MSB_REGS,
+			data->buffer, 3 * sizeof(__be16));
+
 	mutex_unlock(&data->lock);
 	if (ret < 0)
 		goto done;
@@ -508,8 +519,8 @@ static int hmc5843_init(struct hmc5843_data *data)
 	int ret;
 	u8 id[3];
 
-	ret = i2c_smbus_read_i2c_block_data(data->client, HMC5843_ID_REG,
-		sizeof(id), id);
+	ret = regmap_bulk_read(data->regmap, HMC5843_ID_REG,
+			id, ARRAY_SIZE(id));
 	if (ret < 0)
 		return ret;
 	if (id[0] != 'H' || id[1] != '4' || id[2] != '3') {
@@ -539,6 +550,44 @@ static const struct iio_info hmc5843_info = {
 
 static const unsigned long hmc5843_scan_masks[] = {0x7, 0};
 
+static const struct regmap_range hmc5843_readable_ranges[] = {
+		regmap_reg_range(0, HMC5843_ID_END),
+};
+
+static struct regmap_access_table hmc5843_readable_table = {
+		.yes_ranges = hmc5843_readable_ranges,
+		.n_yes_ranges = ARRAY_SIZE(hmc5843_readable_ranges),
+};
+
+static const struct regmap_range hmc5843_writable_ranges[] = {
+		regmap_reg_range(0, HMC5843_MODE_REG),
+};
+
+static struct regmap_access_table hmc5843_writable_table = {
+		.yes_ranges = hmc5843_writable_ranges,
+		.n_yes_ranges = ARRAY_SIZE(hmc5843_writable_ranges),
+};
+
+static const struct regmap_range hmc5843_volatile_ranges[] = {
+		regmap_reg_range(HMC5843_DATA_OUT_MSB_REGS, HMC5843_STATUS_REG),
+};
+
+static struct regmap_access_table hmc5843_volatile_table = {
+		.yes_ranges = hmc5843_volatile_ranges,
+		.n_yes_ranges = ARRAY_SIZE(hmc5843_volatile_ranges),
+};
+
+static struct regmap_config hmc5843_regmap_config = {
+		.reg_bits = 8,
+		.val_bits = 8,
+
+		.rd_table = &hmc5843_readable_table,
+		.wr_table = &hmc5843_writable_table,
+		.volatile_table = &hmc5843_volatile_table,
+
+		.cache_type = REGCACHE_RBTREE,
+};
+
 static int hmc5843_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -554,6 +603,7 @@ static int hmc5843_probe(struct i2c_client *client,
 	data = iio_priv(indio_dev);
 	data->client = client;
 	data->variant = &hmc5843_chip_info_tbl[id->driver_data];
+	data->regmap = devm_regmap_init_i2c(client, &hmc5843_regmap_config);
 	mutex_init(&data->lock);
 
 	i2c_set_clientdata(client, indio_dev);