iio: inv-mpu: Specify the expected format/precision for write channels

commit 6a3c45bb5a385be7049a7725a4fe93eaa76915f4 upstream.

The gyroscope needs IIO_VAL_INT_PLUS_NANO for the scale channel and
unless specified write returns MICRO by default.
This needs to be properly specified so that write operations into scale
have the expected behaviour.

Signed-off-by: Adriana Reus <adriana.reus@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
index 0c6517c94a9db9faf12783b57332f100540fd6fd..63468e3c3ac8b0665823dd527fe2e581a4d06a1b 100644 (file)
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
@@ -340,6 +340,23 @@ static int inv_mpu6050_write_fsr(struct inv_mpu6050_state *st, int fsr)
        return 0;
 }
 
+static int inv_write_raw_get_fmt(struct iio_dev *indio_dev,
+                                struct iio_chan_spec const *chan, long mask)
+{
+       switch (mask) {
+       case IIO_CHAN_INFO_SCALE:
+               switch (chan->type) {
+               case IIO_ANGL_VEL:
+                       return IIO_VAL_INT_PLUS_NANO;
+               default:
+                       return IIO_VAL_INT_PLUS_MICRO;
+               }
+       default:
+               return IIO_VAL_INT_PLUS_MICRO;
+       }
+
+       return -EINVAL;
+}
 static int inv_mpu6050_write_accel_fs(struct inv_mpu6050_state *st, int fs)
 {
        int result;
@@ -603,6 +620,7 @@ static const struct iio_info mpu_info = {
        .driver_module = THIS_MODULE,
        .read_raw = &inv_mpu6050_read_raw,
        .write_raw = &inv_mpu6050_write_raw,
+       .write_raw_get_fmt = &inv_write_raw_get_fmt,
        .attrs = &inv_attribute_group,
        .validate_trigger = inv_mpu6050_validate_trigger,
 };