HID: wacom: Provide battery charge state to system over USB if available

If a wireless adapter (which contains the charging circuitry) is
detected as being attached to the tablet then create a new battery
interface and update its status as data is reported. Also destroy the
battery if the adapter goes away.

Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Acked-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index 5d57fec177a8..f1e53f15abb5 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -1952,6 +1952,7 @@ static int wacom_wireless_irq(struct wacom_wac *wacom, size_t len)
 
 static int wacom_status_irq(struct wacom_wac *wacom_wac, size_t len)
 {
+        struct wacom *wacom = container_of(wacom_wac, struct wacom, wacom_wac);
         struct wacom_features *features = &wacom_wac->features;
         unsigned char *data = wacom_wac->data;
 
@@ -1965,6 +1966,30 @@ static int wacom_status_irq(struct wacom_wac *wacom_wac, size_t len)
                                     SW_MUTE_DEVICE, data[8] & 0x40);
                 input_sync(wacom_wac->shared->touch_input);
         }
+
+        if (data[9] & 0x02) { /* wireless module is attached */
+                int battery = (data[8] & 0x3f) * 100 / 31;
+                bool ps_connected = !!(data[8] & 0x80);
+                bool charging = ps_connected &&
+                                wacom_wac->battery_capacity < 100;
+
+                wacom_notify_battery(wacom_wac, battery, charging,
+                                     ps_connected);
+
+                if (!wacom->battery.dev &&
+                    !(features->quirks & WACOM_QUIRK_BATTERY)) {
+                        features->quirks |= WACOM_QUIRK_BATTERY;
+                        INIT_WORK(&wacom->work, wacom_battery_work);
+                        wacom_schedule_work(wacom_wac);
+                }
+        }
+        else if ((features->quirks & WACOM_QUIRK_BATTERY) &&
+                 wacom->battery.dev) {
+                features->quirks &= ~WACOM_QUIRK_BATTERY;
+                INIT_WORK(&wacom->work, wacom_battery_work);
+                wacom_schedule_work(wacom_wac);
+                wacom_notify_battery(wacom_wac, 0, 0, 0);
+        }
         return 0;
 }