[PATCH] iio: adc: MCP3564: fix calib_bias and calib_scale range checks

From: Javier Carrasco
Date: Fri Dec 01 2023 - 04:48:18 EST


The current implementation uses the AND (&&) operator to check if the
value to write for IIO_CHAN_INFO_CALIBBIAS and IIO_CHAN_INFO_CALIBSCALE
is within the valid ranges.
The evaluated values are the lower and upper limits of the ranges,
so this operation always evaluates to false.

The OR (||) operator must be used instead.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@xxxxxxxxx>
---
This bug has been found when looking for use cases of IIO_AVAIL_RANGE
and the fix could not be tested with real hardware. The issue and its
soulution are rather simple, but still some testing and confirmation
would be welcome.
---
drivers/iio/adc/mcp3564.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/mcp3564.c b/drivers/iio/adc/mcp3564.c
index e3f1de5fcc5a..d5fb1cae8aeb 100644
--- a/drivers/iio/adc/mcp3564.c
+++ b/drivers/iio/adc/mcp3564.c
@@ -918,7 +918,7 @@ static int mcp3564_write_raw(struct iio_dev *indio_dev,
mutex_unlock(&adc->lock);
return ret;
case IIO_CHAN_INFO_CALIBBIAS:
- if (val < mcp3564_calib_bias[0] && val > mcp3564_calib_bias[2])
+ if (val < mcp3564_calib_bias[0] || val > mcp3564_calib_bias[2])
return -EINVAL;

mutex_lock(&adc->lock);
@@ -928,7 +928,7 @@ static int mcp3564_write_raw(struct iio_dev *indio_dev,
mutex_unlock(&adc->lock);
return ret;
case IIO_CHAN_INFO_CALIBSCALE:
- if (val < mcp3564_calib_scale[0] && val > mcp3564_calib_scale[2])
+ if (val < mcp3564_calib_scale[0] || val > mcp3564_calib_scale[2])
return -EINVAL;

if (adc->calib_scale == val)

---
base-commit: 994d5c58e50e91bb02c7be4a91d5186292a895c8
change-id: 20231201-mcp3564_range_checks-221708838130

Best regards,
--
Javier Carrasco <javier.carrasco.cruz@xxxxxxxxx>