diff options
| author | Jeremy Fertic <jeremyfertic@gmail.com> | 2018-12-22 21:57:43 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-08 07:21:52 +0200 |
| commit | f16e83170e252f5406e8974c885dbd96329ea381 (patch) | |
| tree | b4a8509f582ec49ab37cb8a77eab1ba4ecf68074 /drivers/staging | |
| parent | ad774285beee4e6cf71b5a87e2114dc04ba9ce41 (diff) | |
staging: iio: adt7316: fix the dac write calculation
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>
Diffstat (limited to 'drivers/staging')
| -rw-r--r-- | drivers/staging/iio/addac/adt7316.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/staging/iio/addac/adt7316.c b/drivers/staging/iio/addac/adt7316.c index 43c318a68b66..68866f552290 100644 --- a/drivers/staging/iio/addac/adt7316.c +++ b/drivers/staging/iio/addac/adt7316.c @@ -1447,7 +1447,7 @@ static ssize_t adt7316_show_DAC(struct adt7316_chip_info *chip, 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; @@ -1465,9 +1465,13 @@ static ssize_t adt7316_store_DAC(struct adt7316_chip_info *chip, 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; } |