| Message ID | 20230311002248.8548-1-william.gray@linaro.org (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | iio: dac: cio-dac: Fix max DAC write value check for 12-bit | expand |
On Fri, 10 Mar 2023 19:22:48 -0500 William Breathitt Gray <william.gray@linaro.org> wrote: > The CIO-DAC series of devices only supports DAC values up to 12-bit > rather than 16-bit. Trying to write a 16-bit value results in only the > lower 12 bits affecting the DAC output which is not what the user > expects. Instead, adjust the DAC write value check to reject values > larger than 12-bit so that they fail explicitly as invalid for the user. > > Fixes: 3b8df5fd526e ("iio: Add IIO support for the Measurement Computing CIO-DAC family") > Cc: stable@vger.kernel.org > Signed-off-by: William Breathitt Gray <william.gray@linaro.org> Applied to the fixes-togreg branch of iio.git. Thanks, Jonathan > --- > drivers/iio/dac/cio-dac.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c > index 791dd999cf29..18a64f72fc18 100644 > --- a/drivers/iio/dac/cio-dac.c > +++ b/drivers/iio/dac/cio-dac.c > @@ -66,8 +66,8 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev, > if (mask != IIO_CHAN_INFO_RAW) > return -EINVAL; > > - /* DAC can only accept up to a 16-bit value */ > - if ((unsigned int)val > 65535) > + /* DAC can only accept up to a 12-bit value */ > + if ((unsigned int)val > 4095) > return -EINVAL; > > priv->chan_out_states[chan->channel] = val; > > base-commit: fe15c26ee26efa11741a7b632e9f23b01aca4cc6
diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c index 791dd999cf29..18a64f72fc18 100644 --- a/drivers/iio/dac/cio-dac.c +++ b/drivers/iio/dac/cio-dac.c @@ -66,8 +66,8 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev, if (mask != IIO_CHAN_INFO_RAW) return -EINVAL; - /* DAC can only accept up to a 16-bit value */ - if ((unsigned int)val > 65535) + /* DAC can only accept up to a 12-bit value */ + if ((unsigned int)val > 4095) return -EINVAL; priv->chan_out_states[chan->channel] = val;
The CIO-DAC series of devices only supports DAC values up to 12-bit rather than 16-bit. Trying to write a 16-bit value results in only the lower 12 bits affecting the DAC output which is not what the user expects. Instead, adjust the DAC write value check to reject values larger than 12-bit so that they fail explicitly as invalid for the user. Fixes: 3b8df5fd526e ("iio: Add IIO support for the Measurement Computing CIO-DAC family") Cc: stable@vger.kernel.org Signed-off-by: William Breathitt Gray <william.gray@linaro.org> --- drivers/iio/dac/cio-dac.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) base-commit: fe15c26ee26efa11741a7b632e9f23b01aca4cc6