From: Oleksij Rempel <o.rempel@pengutronix.de>
Date: Wed, 4 Feb 2026 14:00:33 +0000 (+0100)
Subject: iio: dac: ds4424: reject -128 RAW value
X-Git-Tag: v7.0-rc4~15^2~7^2~12
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5187e03b817c;p=thirdparty%2Fkernel%2Fstable.git

iio: dac: ds4424: reject -128 RAW value

The DS442x DAC uses sign-magnitude encoding, so -128 cannot be represented
in hardware (7-bit magnitude).

Previously, passing -128 resulted in a truncated value that programmed
0mA (magnitude 0) instead of the expected maximum negative current,
effectively failing silently.

Reject -128 to avoid producing the wrong current.

Fixes: d632a2bd8ffc ("iio: dac: ds4422/ds4424 dac driver")
Cc: stable@vger.kernel.org
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---

diff --git a/drivers/iio/dac/ds4424.c b/drivers/iio/dac/ds4424.c
index 6dda8918975a6..c61868f2de316 100644
--- a/drivers/iio/dac/ds4424.c
+++ b/drivers/iio/dac/ds4424.c
@@ -140,7 +140,7 @@ static int ds4424_write_raw(struct iio_dev *indio_dev,
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
-		if (val < S8_MIN || val > S8_MAX)
+		if (val <= S8_MIN || val > S8_MAX)
 			return -EINVAL;
 
 		if (val > 0) {