iio: accel: bmc150: fix endianness when reading axes

BugLink: http://bugs.launchpad.net/bugs/1573034
commit 2215f31dc6f88634c1916362e922b1ecdce0a6b3 upstream.

For big endian platforms, reading the axes will return
invalid values.

The device stores each axis value in a 16 bit little
endian register. The driver uses regmap_read_bulk to get
the axis value, resulting in a 16 bit little endian value.
This needs to be converted to cpu endianness to work
on big endian platforms.

Fix endianness for big endian platforms by converting
the values for the axes read from little endian to
cpu.

This is also partially fixed in commit b6fb9b6d6552 ("iio:
accel: bmc150: optimize transfers in trigger handler").

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/drivers/iio/accel/bmc150-accel-core.c b/drivers/iio/accel/bmc150-accel-core.c
index 2d33f1e821db0098a0d774e6c5d0fd44ba596675..291c61a41c9a8cae12198c207a2f12afd5d5532c 100644 (file)
--- a/drivers/iio/accel/bmc150-accel-core.c
+++ b/drivers/iio/accel/bmc150-accel-core.c
@@ -547,7 +547,7 @@ static int bmc150_accel_get_axis(struct bmc150_accel_data *data,
 {
        int ret;
        int axis = chan->scan_index;
-       unsigned int raw_val;
+       __le16 raw_val;
 
        mutex_lock(&data->mutex);
        ret = bmc150_accel_set_power_state(data, true);
@@ -557,14 +557,14 @@ static int bmc150_accel_get_axis(struct bmc150_accel_data *data,
        }
 
        ret = regmap_bulk_read(data->regmap, BMC150_ACCEL_AXIS_TO_REG(axis),
-                              &raw_val, 2);
+                              &raw_val, sizeof(raw_val));
        if (ret < 0) {
                dev_err(data->dev, "Error reading axis %d\n", axis);
                bmc150_accel_set_power_state(data, false);
                mutex_unlock(&data->mutex);
                return ret;
        }
-       *val = sign_extend32(raw_val >> chan->scan_type.shift,
+       *val = sign_extend32(le16_to_cpu(raw_val) >> chan->scan_type.shift,
                             chan->scan_type.realbits - 1);
        ret = bmc150_accel_set_power_state(data, false);
        mutex_unlock(&data->mutex);
@@ -988,6 +988,7 @@ static const struct iio_event_spec bmc150_accel_event = {
                .realbits = (bits),                                     \
                .storagebits = 16,                                      \
                .shift = 16 - (bits),                                   \
+               .endianness = IIO_LE,                                   \
        },                                                              \
        .event_spec = &bmc150_accel_event,                              \
        .num_event_specs = 1                                            \