power_supply: Add a charge_type property, and use it for olpc driver

This adds a new sysfs file called 'charge_type' which displays the
type of charging (unknown, n/a, trickle charge, or fast charging).

This allows things like battery diagnostics to determine what the
battery/EC is doing without resorting to changing the 'status' sysfs
output.

Signed-off-by: Andres Salomon <dilinger@collabora.co.uk>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

Documentation/power/power_supply_class.txt

@@ -76,6 +76,11 @@ STATUS - this attribute represents operating status (charging, full,
 discharging (i.e. powering a load), etc.). This corresponds to
 BATTERY_STATUS_* values, as defined in battery.h.
 
+CHARGE_TYPE - batteries can typically charge at different rates.
+This defines trickle and fast charges.  For batteries that
+are already charged or discharging, 'n/a' can be displayed (or
+'unknown', if the status is not known).
+
 HEALTH - represents health of the battery, values corresponds to
 POWER_SUPPLY_HEALTH_*, defined in battery.h.
 

drivers/power/olpc_battery.c

@@ -233,6 +233,14 @@ static int olpc_bat_get_property(struct power_supply *psy,
 		if (ret)
 			return ret;
 		break;
+	case POWER_SUPPLY_PROP_CHARGE_TYPE:
+		if (ec_byte & BAT_STAT_TRICKLE)
+			val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
+		else if (ec_byte & BAT_STAT_CHARGING)
+			val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
+		else
+			val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
+		break;
 	case POWER_SUPPLY_PROP_PRESENT:
 		val->intval = !!(ec_byte & (BAT_STAT_PRESENT |
 					    BAT_STAT_TRICKLE));
@@ -325,6 +333,7 @@ static int olpc_bat_get_property(struct power_supply *psy,
 
 static enum power_supply_property olpc_bat_props[] = {
 	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_CHARGE_TYPE,
 	POWER_SUPPLY_PROP_PRESENT,
 	POWER_SUPPLY_PROP_HEALTH,
 	POWER_SUPPLY_PROP_TECHNOLOGY,

drivers/power/power_supply_sysfs.c

@@ -43,6 +43,9 @@ static ssize_t power_supply_show_property(struct device *dev,
 	static char *status_text[] = {
 		"Unknown", "Charging", "Discharging", "Not charging", "Full"
 	};
+	static char *charge_type[] = {
+		"Unknown", "N/A", "Trickle", "Fast"
+	};
 	static char *health_text[] = {
 		"Unknown", "Good", "Overheat", "Dead", "Over voltage",
 		"Unspecified failure", "Cold",
@@ -70,6 +73,8 @@ static ssize_t power_supply_show_property(struct device *dev,
 
 	if (off == POWER_SUPPLY_PROP_STATUS)
 		return sprintf(buf, "%s\n", status_text[value.intval]);
+	else if (off == POWER_SUPPLY_PROP_CHARGE_TYPE)
+		return sprintf(buf, "%s\n", charge_type[value.intval]);
 	else if (off == POWER_SUPPLY_PROP_HEALTH)
 		return sprintf(buf, "%s\n", health_text[value.intval]);
 	else if (off == POWER_SUPPLY_PROP_TECHNOLOGY)
@@ -86,6 +91,7 @@ static ssize_t power_supply_show_property(struct device *dev,
 static struct device_attribute power_supply_attrs[] = {
 	/* Properties of type `int' */
 	POWER_SUPPLY_ATTR(status),
+	POWER_SUPPLY_ATTR(charge_type),
 	POWER_SUPPLY_ATTR(health),
 	POWER_SUPPLY_ATTR(present),
 	POWER_SUPPLY_ATTR(online),

include/linux/power_supply.h

@@ -38,6 +38,13 @@ enum {
 	POWER_SUPPLY_STATUS_FULL,
 };
 
+enum {
+	POWER_SUPPLY_CHARGE_TYPE_UNKNOWN = 0,
+	POWER_SUPPLY_CHARGE_TYPE_NONE,
+	POWER_SUPPLY_CHARGE_TYPE_TRICKLE,
+	POWER_SUPPLY_CHARGE_TYPE_FAST,
+};
+
 enum {
 	POWER_SUPPLY_HEALTH_UNKNOWN = 0,
 	POWER_SUPPLY_HEALTH_GOOD,
@@ -70,6 +77,7 @@ enum {
 enum power_supply_property {
 	/* Properties of type `int' */
 	POWER_SUPPLY_PROP_STATUS = 0,
+	POWER_SUPPLY_PROP_CHARGE_TYPE,
 	POWER_SUPPLY_PROP_HEALTH,
 	POWER_SUPPLY_PROP_PRESENT,
 	POWER_SUPPLY_PROP_ONLINE,