4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Lorenzo Bianconi <[email protected]> commit 65c8aea07de11b6507efa175edb44bd8b4488218 upstream. Using realbits as i2c/spi read len, when that value is not byte aligned (e.g 12 bits), lead to skip msb part of out data registers. Fix this taking into account scan_type.shift in addition to scan_type.realbits as read length: read_len = DIV_ROUND_UP(realbits + shift, 8) This fix has been tested on 8, 12, 16, 24 bit sensors Fixes: e7385de5291e ("iio:st_sensors: align on storagebits boundaries") Signed-off-by: Lorenzo Bianconi <[email protected]> Tested-by: Linus Walleij <[email protected]> Signed-off-by: Jonathan Cameron <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/iio/common/st_sensors/st_sensors_buffer.c | 4 +++- drivers/iio/common/st_sensors/st_sensors_core.c | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) --- a/drivers/iio/common/st_sensors/st_sensors_buffer.c +++ b/drivers/iio/common/st_sensors/st_sensors_buffer.c @@ -30,7 +30,9 @@ static int st_sensors_get_buffer_element for_each_set_bit(i, indio_dev->active_scan_mask, num_data_channels) { const struct iio_chan_spec *channel = &indio_dev->channels[i]; - unsigned int bytes_to_read = channel->scan_type.realbits >> 3; + unsigned int bytes_to_read = + DIV_ROUND_UP(channel->scan_type.realbits + + channel->scan_type.shift, 8); unsigned int storage_bytes = channel->scan_type.storagebits >> 3; --- a/drivers/iio/common/st_sensors/st_sensors_core.c +++ b/drivers/iio/common/st_sensors/st_sensors_core.c @@ -483,8 +483,10 @@ static int st_sensors_read_axis_data(str int err; u8 *outdata; struct st_sensor_data *sdata = iio_priv(indio_dev); - unsigned int byte_for_channel = ch->scan_type.realbits >> 3; + unsigned int byte_for_channel; + byte_for_channel = DIV_ROUND_UP(ch->scan_type.realbits + + ch->scan_type.shift, 8); outdata = kmalloc(byte_for_channel, GFP_KERNEL); if (!outdata) return -ENOMEM;
