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Commit a8175ba3 authored by Crestez Dan Leonard's avatar Crestez Dan Leonard Committed by Jonathan Cameron
Browse files

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: default avatarCrestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent fbced0e9

drivers/iio/magnetometer/ak8975.c

+12 −8
Original line number Diff line number Diff line
@@ -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;
@@ -543,8 +543,8 @@ 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],

	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");
@@ -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: