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>
diff --git a/drivers/power/power_supply_sysfs.c b/drivers/power/power_supply_sysfs.c
index 9deabbd..0814439 100644
--- a/drivers/power/power_supply_sysfs.c
+++ b/drivers/power/power_supply_sysfs.c
@@ -43,6 +43,9 @@
 	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 @@
 
 	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 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),