linux-kernel - [PATCH v1 1/1] hwmon: (isl28022) Fix current reading calculation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250519061637.8796-2-yikai.tsai.wiwynn@gmail.com>
Date: Mon, 19 May 2025 14:16:36 +0800
From: Yikai Tsai <yikai.tsai.wiwynn@...il.com>
To: patrick@...cx.xyz,
	Carsten Spieß <mail@...sten-spiess.de>,
	Jean Delvare <jdelvare@...e.com>,
	Guenter Roeck <linux@...ck-us.net>
Cc: Yikai Tsai <yikai.tsai.wiwynn@...il.com>,
	linux-hwmon@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v1 1/1] hwmon: (isl28022) Fix current reading calculation

According to the ISL28022 datasheet, bit15 of the current register is
representing -32768. Fix the calculation to properly handle this bit,
ensuring correct measurements for negative values.

Signed-off-by: Yikai Tsai <yikai.tsai.wiwynn@...il.com>
---
 drivers/hwmon/isl28022.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/isl28022.c b/drivers/hwmon/isl28022.c
index 1fb9864635db..6d8cdf80c9ea 100644
--- a/drivers/hwmon/isl28022.c
+++ b/drivers/hwmon/isl28022.c
@@ -161,8 +161,9 @@ static int isl28022_read_current(struct device *dev, u32 attr, long *val)
 				  ISL28022_REG_CURRENT, &regval);
 		if (err < 0)
 			return err;
-		*val = ((long)regval * 1250L * (long)data->gain) /
-			(long)data->shunt;
+		sign_bit = (regval >> 15) & 0x01;
+		*val = (((long)(((u16)regval) & 0x7FFF) - (sign_bit * 32768)) *
+			1250L * (long)data->gain) / (long)data->shunt;
 		break;
 	default:
 		return -EOPNOTSUPP;
-- 
2.25.1