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From:   Eliav Farber <farbere@amazon.com>
To:     <jdelvare@suse.com>, <linux@roeck-us.net>, <robh+dt@kernel.org>,
        <mark.rutland@arm.com>, <linux-hwmon@vger.kernel.org>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
CC:     <farbere@amazon.com>, <talel@amazon.com>, <hhhawa@amazon.com>,
        <jonnyc@amazon.com>, <hanochu@amazon.com>, <ronenk@amazon.com>,
        <itamark@amazon.com>, <shellykz@amazon.com>, <shorer@amazon.com>,
        <amitlavi@amazon.com>, <almogbs@amazon.com>, <dwmw@amazon.co.uk>,
        <rtanwar@maxlinear.com>
Subject: [PATCH v2 11/16] hwmon: (mr75203) add protection for negative voltage value
Date:   Wed, 17 Aug 2022 05:43:16 +0000
Message-ID: <20220817054321.6519-12-farbere@amazon.com>
In-Reply-To: <20220817054321.6519-1-farbere@amazon.com>
References: <20220817054321.6519-1-farbere@amazon.com>
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This change makes sure the returned voltage vlaue is 0 or positive.

Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 drivers/hwmon/mr75203.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c
index 24a00339cfd8..e3191f590167 100644
--- a/drivers/hwmon/mr75203.c
+++ b/drivers/hwmon/mr75203.c
@@ -218,6 +218,13 @@ static int pvt_read_in(struct device *dev, u32 attr, int channel, long *val)
 			return ret;
 
 		n &= SAMPLE_DATA_MSK;
+
+		/* Voltage can't be negative */
+		if (PVT_N_CONST * n < PVT_R_CONST) {
+			*val = 0;
+			return 0;
+		}
+
 		/* Convert the N bitstream count into voltage */
 		*val = pvt->vd[channel].pre_scaler;
 		*val *= (PVT_N_CONST * n - PVT_R_CONST);
-- 
2.37.1