linux-kernel - [PATCH 2/3] hwmon: tmp421: report /PVLD condition

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Message-Id: <20210922134154.20766-2-fercerpav@gmail.com>
Date:   Wed, 22 Sep 2021 16:41:53 +0300
From:   Paul Fertser <fercerpav@...il.com>
To:     linux-hwmon@...r.kernel.org
Cc:     Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        linux-kernel@...r.kernel.org, Paul Fertser <fercerpav@...il.com>
Subject: [PATCH 2/3] hwmon: tmp421: report /PVLD condition

For both local and remote sensors all the supported ICs can report an
"undervoltage lockout" condition which means the conversion wasn't
properly performed due to insufficient power supply voltage and so the
measurement results can't be trusted.

Signed-off-by: Paul Fertser <fercerpav@...il.com>
---
 drivers/hwmon/tmp421.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/hwmon/tmp421.c b/drivers/hwmon/tmp421.c
index 6175ed4b10bd..9ee4c61531f3 100644
--- a/drivers/hwmon/tmp421.c
+++ b/drivers/hwmon/tmp421.c
@@ -174,10 +174,10 @@ static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
 		return 0;
 	case hwmon_temp_fault:
 		/*
-		 * The OPEN bit signals a fault. This is bit 0 of the temperature
-		 * register (low byte).
+		 * Any of OPEN or /PVLD bits indicate a hardware mulfunction
+		 * and the conversion result may be incorrect
 		 */
-		*val = tmp421->temp[channel] & 0x01;
+		*val = !!(tmp421->temp[channel] & 0x03);
 		return 0;
 	default:
 		return -EOPNOTSUPP;
@@ -190,9 +190,6 @@ static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type,
 {
 	switch (attr) {
 	case hwmon_temp_fault:
-		if (channel == 0)
-			return 0;
-		return 0444;
 	case hwmon_temp_input:
 		return 0444;
 	default:
-- 
2.17.1