4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Lorenzo Bianconi <lorenzo.bianconi83@xxxxxxxxx>
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 <lorenzo.bianconi@xxxxxx>
Tested-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
--
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