[PATCH 5.10 011/406] HID: wacom: remove the battery when the EKR is off

Greg Kroah-Hartman
2023-09-17T19:17:46Z

From: Aaron Armstrong Skomra <aaron.skomra@wacom.com>

commit 9ac6678b95b0dd9458a7a6869f46e51cd55a1d84 upstream.

Currently the EKR battery remains even after we stop getting information
from the device. This can lead to a stale battery persisting indefinitely
in userspace.

The remote sends a heartbeat every 10 seconds. Delete the battery if we
miss two heartbeats (after 21 seconds). Restore the battery once we see
a heartbeat again.

Signed-off-by: Aaron Skomra <skomra@gmail.com>
Signed-off-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com>
Reviewed-by: Jason Gerecke <jason.gerecke@wacom.com>
Fixes: 9f1015d45f62 ("HID: wacom: EKR: attach the power_supply on first connection")
CC: stable@vger.kernel.org
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hid/wacom.h | 1 +
drivers/hid/wacom_sys.c | 25 +++++++++++++++++++++----
drivers/hid/wacom_wac.c | 1 +
drivers/hid/wacom_wac.h | 1 +
4 files changed, 24 insertions(+), 4 deletions(-)

--- a/drivers/hid/wacom.h
+++ b/drivers/hid/wacom.h
@@ -153,6 +153,7 @@ struct wacom_remote {
struct input_dev *input;
bool registered;
struct wacom_battery battery;
+ ktime_t active_time;
} remotes[WACOM_MAX_REMOTES];
};

--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -2529,6 +2529,18 @@ fail:
return;
}

+static void wacom_remote_destroy_battery(struct wacom *wacom, int index)
+{
+ struct wacom_remote *remote = wacom->remote;
+
+ if (remote->remotes[index].battery.battery) {
+ devres_release_group(&wacom->hdev->dev,
+ &remote->remotes[index].battery.bat_desc);
+ remote->remotes[index].battery.battery = NULL;
+ remote->remotes[index].active_time = 0;
+ }
+}
+
static void wacom_remote_destroy_one(struct wacom *wacom, unsigned int index)
{
struct wacom_remote *remote = wacom->remote;
@@ -2543,9 +2555,7 @@ static void wacom_remote_destroy_one(str
remote->remotes[i].registered = false;
spin_unlock_irqrestore(&remote->remote_lock, flags);

- if (remote->remotes[i].battery.battery)
- devres_release_group(&wacom->hdev->dev,
- &remote->remotes[i].battery.bat_desc);
+ wacom_remote_destroy_battery(wacom, i);

if (remote->remotes[i].group.name)
devres_release_group(&wacom->hdev->dev,
@@ -2553,7 +2563,6 @@ static void wacom_remote_destroy_one(str

remote->remotes[i].serial = 0;
remote->remotes[i].group.name = NULL;
- remote->remotes[i].battery.battery = NULL;
wacom->led.groups[i].select = WACOM_STATUS_UNKNOWN;
}
}
@@ -2638,6 +2647,9 @@ static int wacom_remote_attach_battery(s
if (remote->remotes[index].battery.battery)
return 0;

+ if (!remote->remotes[index].active_time)
+ return 0;
+
if (wacom->led.groups[index].select == WACOM_STATUS_UNKNOWN)
return 0;

@@ -2653,6 +2665,7 @@ static void wacom_remote_work(struct wor
{
struct wacom *wacom = container_of(work, struct wacom, remote_work);
struct wacom_remote *remote = wacom->remote;
+ ktime_t kt = ktime_get();
struct wacom_remote_data data;
unsigned long flags;
unsigned int count;
@@ -2679,6 +2692,10 @@ static void wacom_remote_work(struct wor
serial = data.remote[i].serial;
if (data.remote[i].connected) {

+ if (kt - remote->remotes[i].active_time > WACOM_REMOTE_BATTERY_TIMEOUT
+ && remote->remotes[i].active_time != 0)
+ wacom_remote_destroy_battery(wacom, i);
+
if (remote->remotes[i].serial == serial) {
wacom_remote_attach_battery(wacom, i);
continue;
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -1127,6 +1127,7 @@ static int wacom_remote_irq(struct wacom
if (index < 0 || !remote->remotes[index].registered)
goto out;

+ remote->remotes[i].active_time = ktime_get();
input = remote->remotes[index].input;

input_report_key(input, BTN_0, (data[9] & 0x01));
--- a/drivers/hid/wacom_wac.h
+++ b/drivers/hid/wacom_wac.h
@@ -15,6 +15,7 @@
#define WACOM_NAME_MAX 64
#define WACOM_MAX_REMOTES 5
#define WACOM_STATUS_UNKNOWN 255
+#define WACOM_REMOTE_BATTERY_TIMEOUT 21000000000ll

/* packet length for individual models */
#define WACOM_PKGLEN_BBFUN 9