Commit 55ecaf17 authored by Linus Walleij's avatar Linus Walleij Committed by Jonathan Cameron
Browse files

iio: magnetometer: ak8974: Break out measurement 



This breaks out the measurement code to its own function
so we can handle this without swirling it up with the
big switch() statement inside ak8974_read_raw().

Keep a local s16 helper variable for the signed value
coming out of the measurement before assigning it to the
integer *val. The local variable makes the code easier
to read and the compiler will optimize it if possible.

Cc: Nick Reitemeyer <nick.reitemeyer@web.de>
Cc: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: default avatarMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent b67959eb

drivers/iio/magnetometer/ak8974.c

+40 −26
Original line number Diff line number Diff line
@@ -554,41 +554,32 @@ static int ak8974_detect(struct ak8974 *ak8974) 
	return 0;

}



static int ak8974_read_raw(struct iio_dev *indio_dev,

			   struct iio_chan_spec const *chan,

			   int *val, int *val2,

			   long mask)

static int ak8974_measure_channel(struct ak8974 *ak8974, unsigned long address,

				  int *val)

{

	struct ak8974 *ak8974 = iio_priv(indio_dev);

	__le16 hw_values[3];

	int ret = -EINVAL;

	int ret;



	pm_runtime_get_sync(&ak8974->i2c->dev);

	mutex_lock(&ak8974->lock);



	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		if (chan->address > 2) {

			dev_err(&ak8974->i2c->dev, "faulty channel address\n");

			ret = -EIO;

			goto out_unlock;

		}

	/*

	 * We read all axes and discard all but one, for optimized

	 * reading, use the triggered buffer.

	 */

	ret = ak8974_trigmeas(ak8974);

	if (ret)

		goto out_unlock;

	ret = ak8974_getresult(ak8974, hw_values);

	if (ret)

		goto out_unlock;



	/*

		 * We read all axes and discard all but one, for optimized

		 * reading, use the triggered buffer.

	 * This explicit cast to (s16) is necessary as the measurement

	 * is done in 2's complement with positive and negative values.

	 * The follwing assignment to *val will then convert the signed

	 * s16 value to a signed int value.

	 */

		*val = (s16)le16_to_cpu(hw_values[chan->address]);



		ret = IIO_VAL_INT;

	}



	*val = (s16)le16_to_cpu(hw_values[address]);

out_unlock:

	mutex_unlock(&ak8974->lock);

	pm_runtime_mark_last_busy(&ak8974->i2c->dev);
@@ -597,6 +588,29 @@ static int ak8974_read_raw(struct iio_dev *indio_dev, 
	return ret;

}



static int ak8974_read_raw(struct iio_dev *indio_dev,

			   struct iio_chan_spec const *chan,

			   int *val, int *val2,

			   long mask)

{

	struct ak8974 *ak8974 = iio_priv(indio_dev);

	int ret;



	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		if (chan->address > 2) {

			dev_err(&ak8974->i2c->dev, "faulty channel address\n");

			return -EIO;

		}

		ret = ak8974_measure_channel(ak8974, chan->address, val);

		if (ret)

			return ret;

		return IIO_VAL_INT;

	}



	return -EINVAL;

}



static void ak8974_fill_buffer(struct iio_dev *indio_dev)

{

	struct ak8974 *ak8974 = iio_priv(indio_dev);