From: Jeremy Fertic jeremyfertic@gmail.com
commit 78accaea117c1ae878774974fab91ac4a0b0e2b0 upstream.
The lsb calculation is not masking the correct bits from the user input. Subtract 1 from (1 << offset) to correctly set up the mask to be applied to user input.
The lsb register stores its value starting at the bit 7 position. adt7316_store_DAC() currently assumes the value is at the other end of the register. Shift the lsb value before storing it in a new variable lsb_reg, and write this variable to the lsb register.
Fixes: 35f6b6b86ede ("staging: iio: new ADT7316/7/8 and ADT7516/7/9 driver") Signed-off-by: Jeremy Fertic jeremyfertic@gmail.com Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/staging/iio/addac/adt7316.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
--- a/drivers/staging/iio/addac/adt7316.c +++ b/drivers/staging/iio/addac/adt7316.c @@ -1450,7 +1450,7 @@ static ssize_t adt7316_show_DAC(struct a static ssize_t adt7316_store_DAC(struct adt7316_chip_info *chip, int channel, const char *buf, size_t len) { - u8 msb, lsb, offset; + u8 msb, lsb, lsb_reg, offset; u16 data; int ret;
@@ -1468,9 +1468,13 @@ static ssize_t adt7316_store_DAC(struct return -EINVAL;
if (chip->dac_bits > 8) { - lsb = data & (1 << offset); + lsb = data & ((1 << offset) - 1); + if (chip->dac_bits == 12) + lsb_reg = lsb << ADT7316_DA_12_BIT_LSB_SHIFT; + else + lsb_reg = lsb << ADT7316_DA_10_BIT_LSB_SHIFT; ret = chip->bus.write(chip->bus.client, - ADT7316_DA_DATA_BASE + channel * 2, lsb); + ADT7316_DA_DATA_BASE + channel * 2, lsb_reg); if (ret) return -EIO; }