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Subject[PATCH v9 2/2] HID: steam: add battery device.
Date
The wireless Steam Controller is battery operated, so add the battery
device and power information.
---
drivers/hid/hid-steam.c | 141 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 140 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-steam.c b/drivers/hid/hid-steam.c
index 36fc85714ea5..af7ebb618867 100644
--- 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 @@ static int steam_register(struct steam_device *steam)
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;
--
2.17.0
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