hwmon: (nct7904) Read all SMI status registers in probe function

When nct7904 power up, it compares current sensor readings against the
default threshold immediately. This results in false alarms on startup.
Read all SMI status registers in probe function to clear the alarms.

Signed-off-by: Amy Shih <[email protected]>
[groeck: Reworded description]
Signed-off-by: Guenter Roeck <[email protected]>

Author: ChiaYuShih

drivers/hwmon/nct7904.c

@@ -41,6 +41,7 @@
 #define FANCTL_MAX		4	/* Counted from 1 */
 #define TCPU_MAX		8	/* Counted from 1 */
 #define TEMP_MAX		4	/* Counted from 1 */
+#define SMI_STS_MAX		10	/* Counted from 1 */
 
 #define VT_ADC_CTRL0_REG	0x20	/* Bank 0 */
 #define VT_ADC_CTRL1_REG	0x21	/* Bank 0 */
@@ -1009,6 +1010,13 @@ static int nct7904_probe(struct i2c_client *client,
 		data->fan_mode[i] = ret;
 	}
 
+	/* Read all of SMI status register to clear alarms */
+	for (i = 0; i < SMI_STS_MAX; i++) {
+		ret = nct7904_read_reg(data, BANK_0, SMI_STS1_REG + i);
+		if (ret < 0)
+			return ret;
+	}
+
 	hwmon_dev =
 		devm_hwmon_device_register_with_info(dev, client->name, data,
 						     &nct7904_chip_info, NULL);