From 2013607b85f03ff24a5a19933705905a1b324a31 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Wed, 26 May 2021 08:40:20 -0700 Subject: hwmon: (max31790) Clear fan fault after reporting it MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fault bits in MAX31790 are sticky and have to be cleared explicitly. A write operation into either the 'Target Duty Cycle' register or the 'Target Count' register is necessary to clear a fault. At the same time, we can never clear cached fault status values before reading them because the companion fault status for any given fan is cleared as well when clearing a fault. Cc: Jan Kundrát Cc: Václav Kubernát Signed-off-by: Guenter Roeck Tested-by: Václav Kubernát Link: https://lore.kernel.org/r/20210526154022.3223012-6-linux@roeck-us.net --- drivers/hwmon/max31790.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'drivers/hwmon/max31790.c') diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c index 67677c437768..7927468c5271 100644 --- a/drivers/hwmon/max31790.c +++ b/drivers/hwmon/max31790.c @@ -80,7 +80,7 @@ static struct max31790_data *max31790_update_device(struct device *dev) MAX31790_REG_FAN_FAULT_STATUS1); if (rv < 0) goto abort; - data->fault_status = rv & 0x3F; + data->fault_status |= rv & 0x3F; rv = i2c_smbus_read_byte_data(client, MAX31790_REG_FAN_FAULT_STATUS2); @@ -181,7 +181,21 @@ static int max31790_read_fan(struct device *dev, u32 attr, int channel, *val = rpm; return 0; case hwmon_fan_fault: + mutex_lock(&data->update_lock); *val = !!(data->fault_status & (1 << channel)); + data->fault_status &= ~(1 << channel); + /* + * If a fault bit is set, we need to write into one of the fan + * configuration registers to clear it. Note that this also + * clears the fault for the companion channel if enabled. + */ + if (*val) { + int reg = MAX31790_REG_TARGET_COUNT(channel % NR_CHANNEL); + + i2c_smbus_write_byte_data(data->client, reg, + data->target_count[channel % NR_CHANNEL] >> 8); + } + mutex_unlock(&data->update_lock); return 0; default: return -EOPNOTSUPP; -- cgit v1.2.3