ACPI: battery: Add the ThinkPad "Not Charging" quirk

The EC/ACPI firmware on Lenovo ThinkPads used to report a status
of "Unknown" when the battery is between the charge start and
charge stop thresholds. On Windows, it reports "Not Charging"
so the quirk has been added to also report correctly.

Now the "status" attribute returns "Not Charging" when the
battery on ThinkPads is not physicaly charging.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/battery.c

@@ -53,6 +53,7 @@ static int battery_bix_broken_package;
 static int battery_notification_delay_ms;
 static int battery_ac_is_broken;
 static int battery_check_pmic = 1;
+static int battery_quirk_notcharging;
 static unsigned int cache_time = 1000;
 module_param(cache_time, uint, 0644);
 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
@@ -217,6 +218,8 @@ static int acpi_battery_get_property(struct power_supply *psy,
 			val->intval = POWER_SUPPLY_STATUS_CHARGING;
 		else if (acpi_battery_is_charged(battery))
 			val->intval = POWER_SUPPLY_STATUS_FULL;
+		else if (battery_quirk_notcharging)
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
 		else
 			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
 		break;
@@ -1111,6 +1114,12 @@ battery_do_not_check_pmic_quirk(const struct dmi_system_id *d)
 	return 0;
 }
 
+static int __init battery_quirk_not_charging(const struct dmi_system_id *d)
+{
+	battery_quirk_notcharging = 1;
+	return 0;
+}
+
 static const struct dmi_system_id bat_dmi_table[] __initconst = {
 	{
 		/* NEC LZ750/LS */
@@ -1155,6 +1164,19 @@ static const struct dmi_system_id bat_dmi_table[] __initconst = {
 			DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo MIIX 320-10ICR"),
 		},
 	},
+	{
+		/*
+		 * On Lenovo ThinkPads the BIOS specification defines
+		 * a state when the bits for charging and discharging
+		 * are both set to 0. That state is "Not Charging".
+		 */
+		.callback = battery_quirk_not_charging,
+		.ident = "Lenovo ThinkPad",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad"),
+		},
+	},
 	{},
 };