[PATCH 3/3] HID: steam: add battery device.

From: Rodrigo Rivas Costa
Date: Tue Feb 13 2018 - 07:03:57 EST


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

Signed-off-by: Rodrigo Rivas Costa <rodrigorivascosta@xxxxxxxxx>
---
drivers/hid/hid-steam.c | 139 +++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 138 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-steam.c b/drivers/hid/hid-steam.c
index f269a986e2be..eb2424688092 100644
--- a/drivers/hid/hid-steam.c
+++ b/drivers/hid/hid-steam.c
@@ -20,6 +20,7 @@
#include <linux/hid.h>
#include <linux/module.h>
#include <linux/workqueue.h>
+#include <linux/power_supply.h>
#include "hid-ids.h"

MODULE_LICENSE("GPL");
@@ -35,6 +36,10 @@ struct steam_device {
struct work_struct work_connect;
bool connected;
char serial_no[11];
+ struct power_supply_desc battery_desc;
+ struct power_supply *battery;
+ u8 battery_charge;
+ u16 voltage;
};

static int steam_register(struct steam_device *steam);
@@ -45,6 +50,8 @@ static int steam_send_report(struct steam_device *steam,
u8 *cmd, int size);
static int steam_recv_report(struct steam_device *steam,
u8 *data, int size);
+static int steam_battery_register(struct steam_device *steam);
+static void steam_do_battery_event(struct steam_device *steam, u8 *data);

static int steam_input_open(struct input_dev *dev)
{
@@ -311,7 +318,8 @@ static int steam_raw_event(struct hid_device *hdev,
}
break;
case 0x04:
- /* TODO battery status */
+ if (steam->quirks & STEAM_QUIRK_WIRELESS)
+ steam_do_battery_event(steam, data);
break;
}
return 0;
@@ -517,6 +525,10 @@ static int steam_register(struct steam_device *steam)

steam->input_dev = input;

+ /* ignore battery errors, we can live without it */
+ if (steam->quirks & STEAM_QUIRK_WIRELESS)
+ steam_battery_register(steam);
+
return 0;

input_register_fail:
@@ -528,6 +540,12 @@ static void steam_unregister(struct steam_device *steam)
{
dbg_hid("%s\n", __func__);

+ if (steam->battery) {
+ power_supply_unregister(steam->battery);
+ steam->battery = NULL;
+ kfree(steam->battery_desc.name);
+ steam->battery_desc.name = NULL;
+ }
if (steam->input_dev) {
hid_info(steam->hid_dev, "Steam Controller SN: '%s' disconnected",
steam->serial_no);
@@ -536,6 +554,125 @@ static void steam_unregister(struct steam_device *steam)
}
}

+/* 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, u8 *data)
+{
+ unsigned long flags;
+ s16 volts = le16_to_cpup((__le16 *)(data + 12));
+ u8 batt = data[14];
+
+ dbg_hid("%s: %d %d\n", __func__, volts, batt);
+
+ if (unlikely(!steam->battery)) {
+ dbg_hid("%s: battery data without connect event\n", __func__);
+ steam_do_connect_event(steam, true);
+ return;
+ }
+
+ spin_lock_irqsave(&steam->lock, flags);
+ steam->voltage = volts;
+ steam->battery_charge = batt;
+ spin_unlock_irqrestore(&steam->lock, flags);
+
+ power_supply_changed(steam->battery);
+}
+
+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;
+
+ dbg_hid("%s\n", __func__);
+
+ 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 = kasprintf(GFP_KERNEL,
+ "steam-controller-%s-battery", steam->serial_no);
+ if (!steam->battery_desc.name) {
+ ret = -ENOMEM;
+ goto print_name_fail;
+ }
+
+ /* 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->hid_dev->dev,
+ &steam->battery_desc, &battery_cfg);
+ if (IS_ERR(battery)) {
+ ret = PTR_ERR(battery);
+ hid_err(steam->hid_dev,
+ "%s:power_supply_register returned error %d\n",
+ __func__, ret);
+ goto power_supply_reg_fail;
+ }
+ steam->battery = battery;
+ power_supply_powers(steam->battery, &steam->hid_dev->dev);
+ return 0;
+
+power_supply_reg_fail:
+ kfree(steam->battery_desc.name);
+ steam->battery_desc.name = NULL;
+print_name_fail:
+ return ret;
+}
+
static const struct hid_device_id steam_controllers[] = {
{ /* Wired Steam Controller */
HID_USB_DEVICE(USB_VENDOR_ID_VALVE,
--
2.16.1