HID: wiimote: Read wiimote battery charge level

This registers a power_supply device for every remote to retrieve the current
battery charge level. Since this information is not sent by the wiimote
continously, we need to explicitely request it.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 61 insertions, 0 deletions

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 1130a8987125..9907dc9cfb12 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -590,6 +590,7 @@ config HID_WIIMOTE
         tristate "Nintendo Wii Remote support"
         depends on BT_HIDP
         depends on LEDS_CLASS
+        select POWER_SUPPLY
         ---help---
         Support for the Nintendo Wii Remote bluetooth device.
 
diff --git a/drivers/hid/hid-wiimote.c b/drivers/hid/hid-wiimote.c
index 48198cb0fed2..c83cafaa46a3 100644
--- a/drivers/hid/hid-wiimote.c
+++ b/drivers/hid/hid-wiimote.c
@@ -17,6 +17,7 @@
 #include <linux/leds.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/power_supply.h>
 #include <linux/spinlock.h>
 #include "hid-ids.h"
 
@@ -51,6 +52,7 @@ struct wiimote_data {
         struct led_classdev *leds[4];
         struct input_dev *accel;
         struct input_dev *ir;
+        struct power_supply battery;
 
         spinlock_t qlock;
         __u8 head;
@@ -133,6 +135,10 @@ static __u16 wiiproto_keymap[] = {
         BTN_MODE,       /* WIIPROTO_KEY_HOME */
 };
 
+static enum power_supply_property wiimote_battery_props[] = {
+        POWER_SUPPLY_PROP_CAPACITY
+};
+
 /* requires the state.lock spinlock to be held */
 static inline bool wiimote_cmd_pending(struct wiimote_data *wdata, int cmd,
                                                                 __u32 opt)
@@ -453,6 +459,43 @@ static int wiimote_cmd_write(struct wiimote_data *wdata, __u32 offset,
         return ret;
 }
 
+static int wiimote_battery_get_property(struct power_supply *psy,
+                                                enum power_supply_property psp,
+                                                union power_supply_propval *val)
+{
+        struct wiimote_data *wdata = container_of(psy,
+                                                struct wiimote_data, battery);
+        int ret = 0, state;
+        unsigned long flags;
+
+        ret = wiimote_cmd_acquire(wdata);
+        if (ret)
+                return ret;
+
+        spin_lock_irqsave(&wdata->state.lock, flags);
+        wiimote_cmd_set(wdata, WIIPROTO_REQ_SREQ, 0);
+        wiiproto_req_status(wdata);
+        spin_unlock_irqrestore(&wdata->state.lock, flags);
+
+        ret = wiimote_cmd_wait(wdata);
+        state = wdata->state.cmd_battery;
+        wiimote_cmd_release(wdata);
+
+        if (ret)
+                return ret;
+
+        switch (psp) {
+                case POWER_SUPPLY_PROP_CAPACITY:
+                        val->intval = state * 100 / 255;
+                        break;
+                default:
+                        ret = -EINVAL;
+                        break;
+        }
+
+        return ret;
+}
+
 static int wiimote_init_ir(struct wiimote_data *wdata, __u16 mode)
 {
         int ret;
@@ -1155,6 +1198,7 @@ static void wiimote_destroy(struct wiimote_data *wdata)
 {
         wiimote_leds_destroy(wdata);
 
+        power_supply_unregister(&wdata->battery);
         input_unregister_device(wdata->accel);
         input_unregister_device(wdata->ir);
         input_unregister_device(wdata->input);
@@ -1206,6 +1250,19 @@ static int wiimote_hid_probe(struct hid_device *hdev,
                 goto err_input;
         }
 
+        wdata->battery.properties = wiimote_battery_props;
+        wdata->battery.num_properties = ARRAY_SIZE(wiimote_battery_props);
+        wdata->battery.get_property = wiimote_battery_get_property;
+        wdata->battery.name = "wiimote_battery";
+        wdata->battery.type = POWER_SUPPLY_TYPE_BATTERY;
+        wdata->battery.use_for_apm = 0;
+
+        ret = power_supply_register(&wdata->hdev->dev, &wdata->battery);
+        if (ret) {
+                hid_err(hdev, "Cannot register battery device\n");
+                goto err_battery;
+        }
+
         ret = wiimote_leds_create(wdata);
         if (ret)
                 goto err_free;
@@ -1223,6 +1280,9 @@ err_free:
         wiimote_destroy(wdata);
         return ret;
 
+err_battery:
+        input_unregister_device(wdata->input);
+        wdata->input = NULL;
 err_input:
         input_unregister_device(wdata->ir);
         wdata->ir = NULL;