iio: ak8975: Support adapters limited to BYTE_DATA

The device has simple 8-bit registers but the driver incorrectly uses
block or word reads without checking functionality bits.

Fix by using i2c_smbus_read_i2c_block_data_or_emulated instead of
i2c_smbus_read_i2c_block_data or i2c_smbus_read_word_data. This will
check functionality bits and use the fastest available transfer method.

Signed-off-by: Crestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
index dbf066129a0408a82b0cfc448b1b0b0bbb17ce13..c24b8a509ed89172d526a60cfa03a5b28980ca1e 100644 (file)
--- a/drivers/iio/magnetometer/ak8975.c
+++ b/drivers/iio/magnetometer/ak8975.c
@@ -430,8 +430,8 @@ static int ak8975_who_i_am(struct i2c_client *client,
         * AK8975   |  DEVICE_ID |  NA
         * AK8963   |  DEVICE_ID |  NA
         */
-       ret = i2c_smbus_read_i2c_block_data(client, AK09912_REG_WIA1,
-                                           2, wia_val);
+       ret = i2c_smbus_read_i2c_block_data_or_emulated(
+                       client, AK09912_REG_WIA1, 2, wia_val);
        if (ret < 0) {
                dev_err(&client->dev, "Error reading WIA\n");
                return ret;
@@ -543,9 +543,9 @@ static int ak8975_setup(struct i2c_client *client)
        }
 
        /* Get asa data and store in the device data. */
-       ret = i2c_smbus_read_i2c_block_data(client,
-                                           data->def->ctrl_regs[ASA_BASE],
-                                           3, data->asa);
+       ret = i2c_smbus_read_i2c_block_data_or_emulated(
+                       client, data->def->ctrl_regs[ASA_BASE],
+                       3, data->asa);
        if (ret < 0) {
                dev_err(&client->dev, "Not able to read asa data\n");
                return ret;
@@ -686,6 +686,7 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
        struct ak8975_data *data = iio_priv(indio_dev);
        const struct i2c_client *client = data->client;
        const struct ak_def *def = data->def;
+       u16 buff;
        int ret;
 
        mutex_lock(&data->lock);
@@ -694,14 +695,17 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
        if (ret)
                goto exit;
 
-       ret = i2c_smbus_read_word_data(client, def->data_regs[index]);
+       ret = i2c_smbus_read_i2c_block_data_or_emulated(
+                       client, def->data_regs[index],
+                       sizeof(buff), (u8*)&buff);
        if (ret < 0)
                goto exit;
 
        mutex_unlock(&data->lock);
 
-       /* Clamp to valid range. */
-       *val = clamp_t(s16, ret, -def->range, def->range);
+       /* Swap bytes and convert to valid range. */
+       buff = le16_to_cpu(buff);
+       *val = clamp_t(s16, buff, -def->range, def->range);
        return IIO_VAL_INT;
 
 exit: