hwmon: (pmbus) Improve support for paged temperature sensors

Assumption so far was that PMBus devices would support TEMP2 and TEMP3 registers
only on page 0, and that only the TEMP1 register would be used/supported
on other pages.

Turns out that is not correct. UCD92xx devices support TEMP1 and TEMP2 on
page 0, and TEMP2 on other pages. So it is necessary to change the core code
such that it does not make a page based assumptions about temperature register
support.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

drivers/hwmon/pmbus_core.c

@@ -797,6 +797,12 @@ static const int pmbus_temp_registers[] = {
 	PMBUS_READ_TEMPERATURE_3
 };
 
+static const int pmbus_temp_flags[] = {
+	PMBUS_HAVE_TEMP,
+	PMBUS_HAVE_TEMP2,
+	PMBUS_HAVE_TEMP3
+};
+
 static const int pmbus_fan_registers[] = {
 	PMBUS_READ_FAN_SPEED_1,
 	PMBUS_READ_FAN_SPEED_2,
@@ -871,17 +877,16 @@ static void pmbus_find_max_attr(struct i2c_client *client,
 			max_booleans += 2 * PMBUS_MAX_BOOLEANS_PER_FAN;
 		}
 		if (info->func[page] & PMBUS_HAVE_TEMP) {
-			if (page == 0) {
-				max_sensors +=
-				    ARRAY_SIZE(pmbus_temp_registers) *
-				    PMBUS_MAX_SENSORS_PER_TEMP;
-				max_booleans +=
-				    ARRAY_SIZE(pmbus_temp_registers) *
-				    PMBUS_MAX_BOOLEANS_PER_TEMP;
-			} else {
 			max_sensors += PMBUS_MAX_SENSORS_PER_TEMP;
 			max_booleans += PMBUS_MAX_BOOLEANS_PER_TEMP;
 		}
+		if (info->func[page] & PMBUS_HAVE_TEMP2) {
+			max_sensors += PMBUS_MAX_SENSORS_PER_TEMP;
+			max_booleans += PMBUS_MAX_BOOLEANS_PER_TEMP;
+		}
+		if (info->func[page] & PMBUS_HAVE_TEMP3) {
+			max_sensors += PMBUS_MAX_SENSORS_PER_TEMP;
+			max_booleans += PMBUS_MAX_BOOLEANS_PER_TEMP;
 		}
 	}
 	data->max_sensors = max_sensors;
@@ -1273,18 +1278,23 @@ static void pmbus_find_attributes(struct i2c_client *client,
 	 */
 	in_index = 1;
 	for (page = 0; page < info->pages; page++) {
-		int t, temps;
+		int t;
 
-		if (!(info->func[page] & PMBUS_HAVE_TEMP))
-			continue;
-
-		temps = page ? 1 : ARRAY_SIZE(pmbus_temp_registers);
-		for (t = 0; t < temps; t++) {
+		for (t = 0; t < ARRAY_SIZE(pmbus_temp_registers); t++) {
 			bool have_alarm = false;
 
+			/*
+			 * A PMBus chip may support any combination of
+			 * temperature registers on any page. So we can not
+			 * abort after a failure to detect a register, but have
+			 * to continue checking for all registers on all pages.
+			 */
+			if (!(info->func[page] & pmbus_temp_flags[t]))
+				continue;
+
 			if (!pmbus_check_word_register
 			    (client, page, pmbus_temp_registers[t]))
-				break;
+				continue;
 
 			i0 = data->num_sensors;
 			pmbus_add_sensor(data, "temp", "input", in_index, page,