hwmon: (adm1275) Add support for peak attributes

Add support for voltage and current peak (historic maximum) attributes.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Robert Coulson <robert.coulson@ericsson.com>

Documentation/hwmon/adm1275

@@ -43,8 +43,8 @@ Documentation/hwmon/pmbus for details.
 Sysfs entries
 -------------
 
-The following attributes are supported. Limits are read-write; all other
-attributes are read-only.
+The following attributes are supported. Limits are read-write, history reset
+attributes are write-only, all other attributes are read-only.
 
 in1_label		"vin1" or "vout1" depending on chip variant and
 			configuration.
@@ -53,8 +53,12 @@ in1_min			Minumum Voltage. From VOUT_UV_WARN_LIMIT register.
 in1_max			Maximum voltage. From VOUT_OV_WARN_LIMIT register.
 in1_min_alarm		Voltage low alarm. From VOLTAGE_UV_WARNING status.
 in1_max_alarm		Voltage high alarm. From VOLTAGE_OV_WARNING status.
+in1_highest		Historical maximum voltage.
+in1_reset_history	Write any value to reset history.
 
 curr1_label		"iout1"
 curr1_input		Measured current. From READ_IOUT register.
 curr1_max		Maximum current. From IOUT_OC_WARN_LIMIT register.
 curr1_max_alarm		Current high alarm. From IOUT_OC_WARN_LIMIT register.
+curr1_highest		Historical maximum current.
+curr1_reset_history	Write any value to reset history.

drivers/hwmon/pmbus/adm1275.c

@@ -23,11 +23,68 @@
 #include <linux/i2c.h>
 #include "pmbus.h"
 
+#define ADM1275_PEAK_IOUT		0xd0
+#define ADM1275_PEAK_VIN		0xd1
+#define ADM1275_PEAK_VOUT		0xd2
 #define ADM1275_PMON_CONFIG		0xd4
 
 #define ADM1275_VIN_VOUT_SELECT		(1 << 6)
 #define ADM1275_VRANGE			(1 << 5)
 
+static int adm1275_read_word_data(struct i2c_client *client, int page, int reg)
+{
+	int ret;
+
+	if (page)
+		return -EINVAL;
+
+	switch (reg) {
+	case PMBUS_VIRT_READ_IOUT_MAX:
+		ret = pmbus_read_word_data(client, 0, ADM1275_PEAK_IOUT);
+		break;
+	case PMBUS_VIRT_READ_VOUT_MAX:
+		ret = pmbus_read_word_data(client, 0, ADM1275_PEAK_VOUT);
+		break;
+	case PMBUS_VIRT_READ_VIN_MAX:
+		ret = pmbus_read_word_data(client, 0, ADM1275_PEAK_VIN);
+		break;
+	case PMBUS_VIRT_RESET_IOUT_HISTORY:
+	case PMBUS_VIRT_RESET_VOUT_HISTORY:
+	case PMBUS_VIRT_RESET_VIN_HISTORY:
+		ret = 0;
+		break;
+	default:
+		ret = -ENODATA;
+		break;
+	}
+	return ret;
+}
+
+static int adm1275_write_word_data(struct i2c_client *client, int page, int reg,
+				   u16 word)
+{
+	int ret;
+
+	if (page)
+		return -EINVAL;
+
+	switch (reg) {
+	case PMBUS_VIRT_RESET_IOUT_HISTORY:
+		ret = pmbus_write_word_data(client, 0, ADM1275_PEAK_IOUT, 0);
+		break;
+	case PMBUS_VIRT_RESET_VOUT_HISTORY:
+		ret = pmbus_write_word_data(client, 0, ADM1275_PEAK_VOUT, 0);
+		break;
+	case PMBUS_VIRT_RESET_VIN_HISTORY:
+		ret = pmbus_write_word_data(client, 0, ADM1275_PEAK_VIN, 0);
+		break;
+	default:
+		ret = -ENODATA;
+		break;
+	}
+	return ret;
+}
+
 static int adm1275_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -58,6 +115,9 @@ static int adm1275_probe(struct i2c_client *client,
 	info->R[PSC_CURRENT_OUT] = -1;
 	info->func[0] = PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT;
 
+	info->read_word_data = adm1275_read_word_data;
+	info->write_word_data = adm1275_write_word_data;
+
 	if (config & ADM1275_VRANGE) {
 		info->m[PSC_VOLTAGE_IN] = 19199;
 		info->b[PSC_VOLTAGE_IN] = 0;