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staging: iio: adt7316: fix the dac write calculation
commit78accaea11
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:35f6b6b86e
("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>
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8c5a4013e6
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1 changed files with 7 additions and 3 deletions
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@ -1450,7 +1450,7 @@ static ssize_t adt7316_show_DAC(struct adt7316_chip_info *chip,
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static ssize_t adt7316_store_DAC(struct adt7316_chip_info *chip,
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int channel, const char *buf, size_t len)
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{
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u8 msb, lsb, offset;
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u8 msb, lsb, lsb_reg, offset;
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u16 data;
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int ret;
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@ -1468,9 +1468,13 @@ static ssize_t adt7316_store_DAC(struct adt7316_chip_info *chip,
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return -EINVAL;
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if (chip->dac_bits > 8) {
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lsb = data & (1 << offset);
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lsb = data & ((1 << offset) - 1);
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if (chip->dac_bits == 12)
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lsb_reg = lsb << ADT7316_DA_12_BIT_LSB_SHIFT;
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else
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lsb_reg = lsb << ADT7316_DA_10_BIT_LSB_SHIFT;
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ret = chip->bus.write(chip->bus.client,
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ADT7316_DA_DATA_BASE + channel * 2, lsb);
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ADT7316_DA_DATA_BASE + channel * 2, lsb_reg);
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if (ret)
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return -EIO;
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}
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