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| author | Jeremy Fertic <jeremyfertic@gmail.com> | 2018-12-22 21:57:43 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-08 07:22:56 +0200 |
| commit | 15e4df25a6b7d8b3f396d7dbc1885343affa2539 (patch) | |
| tree | ced12dd0c161c4b4da57c4a975beed4d981d2385 | |
| parent | 85dbcda147f41cbf9be95864dae0daa25f66473c (diff) | |
| download | linux-stable-15e4df25a6b7d8b3f396d7dbc1885343affa2539.tar.gz linux-stable-15e4df25a6b7d8b3f396d7dbc1885343affa2539.tar.bz2 linux-stable-15e4df25a6b7d8b3f396d7dbc1885343affa2539.zip | |
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>
| -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 b84360ebb57a..ecbb29e2153e 100644 --- a/drivers/staging/iio/addac/adt7316.c +++ b/drivers/staging/iio/addac/adt7316.c @@ -1442,7 +1442,7 @@ 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; @@ -1460,9 +1460,13 @@ 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; } |