From 55ecaf1717c619edce304ba27d68c18876af6637 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Mon, 20 Apr 2020 22:40:21 +0200 Subject: [PATCH] iio: magnetometer: ak8974: Break out measurement MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Stephan Gerhold Reviewed-by: Michał Mirosław Signed-off-by: Linus Walleij Signed-off-by: Jonathan Cameron --- drivers/iio/magnetometer/ak8974.c | 66 +++++++++++++++++++------------ 1 file changed, 40 insertions(+), 26 deletions(-) diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c index bbda572eee3c..71a879c8faa5 100644 --- a/drivers/iio/magnetometer/ak8974.c +++ b/drivers/iio/magnetometer/ak8974.c @@ -554,47 +554,61 @@ static int ak8974_detect(struct ak8974 *ak8974) return 0; } +static int ak8974_measure_channel(struct ak8974 *ak8974, unsigned long address, + int *val) +{ + __le16 hw_values[3]; + int ret; + + pm_runtime_get_sync(&ak8974->i2c->dev); + mutex_lock(&ak8974->lock); + + /* + * 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; + /* + * 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[address]); +out_unlock: + mutex_unlock(&ak8974->lock); + pm_runtime_mark_last_busy(&ak8974->i2c->dev); + pm_runtime_put_autosuspend(&ak8974->i2c->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); - __le16 hw_values[3]; - int ret = -EINVAL; - - pm_runtime_get_sync(&ak8974->i2c->dev); - mutex_lock(&ak8974->lock); + int ret; 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; + return -EIO; } - ret = ak8974_trigmeas(ak8974); + ret = ak8974_measure_channel(ak8974, chan->address, val); 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. - */ - *val = (s16)le16_to_cpu(hw_values[chan->address]); - - ret = IIO_VAL_INT; + return ret; + return IIO_VAL_INT; } - out_unlock: - mutex_unlock(&ak8974->lock); - pm_runtime_mark_last_busy(&ak8974->i2c->dev); - pm_runtime_put_autosuspend(&ak8974->i2c->dev); - - return ret; + return -EINVAL; } static void ak8974_fill_buffer(struct iio_dev *indio_dev)