hwmon: (tmp421) report /PVLD condition as fault

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.

Fixes: 9410700b881f ("hwmon: Add driver for Texas Instruments TMP421/422/423 sensor chips")
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Link: https://lore.kernel.org/r/20210924093011.26083-2-fercerpav@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/tmp421.c b/drivers/hwmon/tmp421.c
index 8fd8c3a94dfe0386abfd972007edb64062d0b4a3..c9ef83627bb73b7fafe3a92c59e472496e1f8de3 100644 (file)
--- a/drivers/hwmon/tmp421.c
+++ b/drivers/hwmon/tmp421.c
@@ -179,10 +179,10 @@ 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;
@@ -195,9 +195,6 @@ 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: