HID: steam: add battery device.

The wireless Steam Controller is battery operated, so add the battery
device and power information.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-steam.c b/drivers/hid/hid-steam.c
index 36fc85714ea5b7b058fa1d61a7ed3ba93e39aaa7..af7ebb6188671c2e3bf721ac9ffbb1a8f4eeace0 100644 (file)
--- a/drivers/hid/hid-steam.c
+++ b/drivers/hid/hid-steam.c
@@ -40,6 +40,7 @@
 #include <linux/mutex.h>
 #include <linux/rcupdate.h>
 #include <linux/delay.h>
+#include <linux/power_supply.h>
 #include "hid-ids.h"
 
 MODULE_LICENSE("GPL");
@@ -118,6 +119,10 @@ struct steam_device {
        struct work_struct work_connect;
        bool connected;
        char serial_no[STEAM_SERIAL_LEN + 1];
+       struct power_supply_desc battery_desc;
+       struct power_supply __rcu *battery;
+       u8 battery_charge;
+       u16 voltage;
 };
 
 static int steam_recv_report(struct steam_device *steam,
@@ -316,6 +321,85 @@ static void steam_input_close(struct input_dev *dev)
        hid_hw_close(steam->hdev);
 }
 
+static enum power_supply_property steam_battery_props[] = {
+       POWER_SUPPLY_PROP_PRESENT,
+       POWER_SUPPLY_PROP_SCOPE,
+       POWER_SUPPLY_PROP_VOLTAGE_NOW,
+       POWER_SUPPLY_PROP_CAPACITY,
+};
+
+static int steam_battery_get_property(struct power_supply *psy,
+                               enum power_supply_property psp,
+                               union power_supply_propval *val)
+{
+       struct steam_device *steam = power_supply_get_drvdata(psy);
+       unsigned long flags;
+       s16 volts;
+       u8 batt;
+       int ret = 0;
+
+       spin_lock_irqsave(&steam->lock, flags);
+       volts = steam->voltage;
+       batt = steam->battery_charge;
+       spin_unlock_irqrestore(&steam->lock, flags);
+
+       switch (psp) {
+       case POWER_SUPPLY_PROP_PRESENT:
+               val->intval = 1;
+               break;
+       case POWER_SUPPLY_PROP_SCOPE:
+               val->intval = POWER_SUPPLY_SCOPE_DEVICE;
+               break;
+       case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+               val->intval = volts * 1000; /* mV -> uV */
+               break;
+       case POWER_SUPPLY_PROP_CAPACITY:
+               val->intval = batt;
+               break;
+       default:
+               ret = -EINVAL;
+               break;
+       }
+       return ret;
+}
+
+static int steam_battery_register(struct steam_device *steam)
+{
+       struct power_supply *battery;
+       struct power_supply_config battery_cfg = { .drv_data = steam, };
+       unsigned long flags;
+       int ret;
+
+       steam->battery_desc.type = POWER_SUPPLY_TYPE_BATTERY;
+       steam->battery_desc.properties = steam_battery_props;
+       steam->battery_desc.num_properties = ARRAY_SIZE(steam_battery_props);
+       steam->battery_desc.get_property = steam_battery_get_property;
+       steam->battery_desc.name = devm_kasprintf(&steam->hdev->dev,
+                       GFP_KERNEL, "steam-controller-%s-battery",
+                       steam->serial_no);
+       if (!steam->battery_desc.name)
+               return -ENOMEM;
+
+       /* avoid the warning of 0% battery while waiting for the first info */
+       spin_lock_irqsave(&steam->lock, flags);
+       steam->voltage = 3000;
+       steam->battery_charge = 100;
+       spin_unlock_irqrestore(&steam->lock, flags);
+
+       battery = power_supply_register(&steam->hdev->dev,
+                       &steam->battery_desc, &battery_cfg);
+       if (IS_ERR(battery)) {
+               ret = PTR_ERR(battery);
+               hid_err(steam->hdev,
+                               "%s:power_supply_register failed with error %d\n",
+                               __func__, ret);
+               return ret;
+       }
+       rcu_assign_pointer(steam->battery, battery);
+       power_supply_powers(battery, &steam->hdev->dev);
+       return 0;
+}
+
 static int steam_register(struct steam_device *steam)
 {
        struct hid_device *hdev = steam->hdev;
@@ -409,6 +493,10 @@ static int steam_register(struct steam_device *steam)
 
        rcu_assign_pointer(steam->input, input);
 
+       /* ignore battery errors, we can live without it */
+       if (steam->quirks & STEAM_QUIRK_WIRELESS)
+               steam_battery_register(steam);
+
        return 0;
 
 input_register_fail:
@@ -419,11 +507,18 @@ input_register_fail:
 static void steam_unregister(struct steam_device *steam)
 {
        struct input_dev *input;
+       struct power_supply *battery;
 
        rcu_read_lock();
        input = rcu_dereference(steam->input);
+       battery = rcu_dereference(steam->battery);
        rcu_read_unlock();
 
+       if (battery) {
+               RCU_INIT_POINTER(steam->battery, NULL);
+               synchronize_rcu();
+               power_supply_unregister(battery);
+       }
        if (input) {
                RCU_INIT_POINTER(steam->input, NULL);
                synchronize_rcu();
@@ -851,12 +946,44 @@ static void steam_do_input_event(struct steam_device *steam,
        input_sync(input);
 }
 
+/*
+ * The size for this message payload is 11.
+ * The known values are:
+ *  Offset| Type  | Meaning
+ * -------+-------+---------------------------
+ *  4-7   | u32   | sequence number
+ *  8-11  | --    | always 0
+ *  12-13 | u16   | voltage (mV)
+ *  14    | u8    | battery percent
+ */
+static void steam_do_battery_event(struct steam_device *steam,
+               struct power_supply *battery, u8 *data)
+{
+       unsigned long flags;
+
+       s16 volts = steam_le16(data + 12);
+       u8 batt = data[14];
+
+       /* Creating the battery may have failed */
+       rcu_read_lock();
+       battery = rcu_dereference(steam->battery);
+       if (likely(battery)) {
+               spin_lock_irqsave(&steam->lock, flags);
+               steam->voltage = volts;
+               steam->battery_charge = batt;
+               spin_unlock_irqrestore(&steam->lock, flags);
+               power_supply_changed(battery);
+       }
+       rcu_read_unlock();
+}
+
 static int steam_raw_event(struct hid_device *hdev,
                        struct hid_report *report, u8 *data,
                        int size)
 {
        struct steam_device *steam = hid_get_drvdata(hdev);
        struct input_dev *input;
+       struct power_supply *battery;
 
        if (!steam)
                return 0;
@@ -914,7 +1041,19 @@ static int steam_raw_event(struct hid_device *hdev,
                }
                break;
        case STEAM_EV_BATTERY:
-               /* TODO: battery info */
+               if (steam->quirks & STEAM_QUIRK_WIRELESS) {
+                       rcu_read_lock();
+                       battery = rcu_dereference(steam->battery);
+                       if (likely(battery)) {
+                               steam_do_battery_event(steam, battery, data);
+                       } else {
+                               dbg_hid(
+                                       "%s: battery data without connect event\n",
+                                       __func__);
+                               steam_do_connect_event(steam, true);
+                       }
+                       rcu_read_unlock();
+               }
                break;
        }
        return 0;