diff options
| author | Guenter Roeck <linux@roeck-us.net> | 2021-05-26 08:40:21 -0700 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2021-06-17 04:21:46 -0700 |
| commit | 1814c4e84de2a89d1c2e1e9bbd241240561075a4 (patch) | |
| tree | fb83823204e878cafb36d6a7b9f2a8f9c81b5867 /drivers/hwmon/max31790.c | |
| parent | 2013607b85f03ff24a5a19933705905a1b324a31 (diff) | |
hwmon: (max31790) Detect and report zero fan speed
If a fan is not running or not connected, of if fan monitoring is disabled,
the fan count register returns a fixed value of 0xffe0. So far this is then
translated to a RPM value larger than 0. Since this is misleading and does
not really make much sense, report a fan RPM of 0 in this situation.
Cc: Jan Kundrát <jan.kundrat@cesnet.cz>
Cc: Václav Kubernát <kubernat@cesnet.cz>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Václav Kubernát <kubernat@cesnet.cz>
Link: https://lore.kernel.org/r/20210526154022.3223012-7-linux@roeck-us.net
Diffstat (limited to 'drivers/hwmon/max31790.c')
| -rw-r--r-- | drivers/hwmon/max31790.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c index 7927468c5271..7e9362f6dc29 100644 --- a/drivers/hwmon/max31790.c +++ b/drivers/hwmon/max31790.c @@ -40,6 +40,8 @@ #define FAN_RPM_MIN 120 #define FAN_RPM_MAX 7864320 +#define FAN_COUNT_REG_MAX 0xffe0 + #define RPM_FROM_REG(reg, sr) (((reg) >> 4) ? \ ((60 * (sr) * 8192) / ((reg) >> 4)) : \ FAN_RPM_MAX) @@ -172,7 +174,10 @@ static int max31790_read_fan(struct device *dev, u32 attr, int channel, switch (attr) { case hwmon_fan_input: sr = get_tach_period(data->fan_dynamics[channel % NR_CHANNEL]); - rpm = RPM_FROM_REG(data->tach[channel], sr); + if (data->tach[channel] == FAN_COUNT_REG_MAX) + rpm = 0; + else + rpm = RPM_FROM_REG(data->tach[channel], sr); *val = rpm; return 0; case hwmon_fan_target: |