[PATCH] hwmon: (w83781d) Clamp voltage limits before rounding

[Zhu Jun]

IN_TO_REG() adds 8 to an unsigned long before clamping. Writing
ULONG_MAX to a voltage limit therefore wraps and programs register zero
instead of 255.

Bound the input to the 0..4080 mV register range before adding the
rounding adjustment.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
---
Validation: x86-64 and i386 driver objects built with W=1.
Source-extracted boundary tests passed on both word sizes;
the corresponding test fails on the base revision. I/O is mocked.
No physical sensor or booted-kernel testing was available.
OpenAI Codex assisted analysis, code, tests and changelog drafting.
Please review and add your own Signed-off-by before submitting.

 drivers/hwmon/w83781d.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/w83781d.c b/drivers/hwmon/w83781d.c
index 59d2b9d40920..0a820e64a7a4 100644
--- a/drivers/hwmon/w83781d.c
+++ b/drivers/hwmon/w83781d.c
@@ -146,7 +146,7 @@ static const u8 BIT_SCFG2[] = { 0x10, 0x20, 0x40 };
 #define W83781D_DEFAULT_BETA		3435
 
 /* Conversions */
-#define IN_TO_REG(val)			clamp_val(((val) + 8) / 16, 0, 255)
+#define IN_TO_REG(val)			((clamp_val((val), 0, 4080) + 8) / 16)
 #define IN_FROM_REG(val)		((val) * 16)
 
 static inline u8

base-commit: 7475ea8b58616b33c04afb976cf0fbaad9dd63fb
-- 
2.51.0