[1/2] HID: wacom: Lazy-init batteries

From: Jason Gerecke <killertofu@gmail.com>

Rather than creating batteries as part of the initial device probe, let's
make the process lazy. This gives us the opportunity to prevent batteries
from being created in situations where they are unnecessary.

There are two cases in particular where batteries are being unnecessarily
created at initialization. These are AES sensors (for which we don't know
any battery status information until a battery-powered pen actually comes
into prox) peripheral tablets which share HID descriptors between the
wired-only and wireless-capable SKUs of a family of devices.

This patch will delay battery initialization of the former until a pen
actually comes into prox. It will delay battery initialization of the
latter until either a pen comes into prox or a "heartbeat" packet is
processed.

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Tested-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/hid/wacom_sys.c | 10 ----------
 drivers/hid/wacom_wac.c | 13 ++++++-------
 2 files changed, 6 insertions(+), 17 deletions(-)

[Public]

> From: Jason Gerecke <killertofu@gmail.com>
> 
> Rather than creating batteries as part of the initial device probe, let's
> make the process lazy. This gives us the opportunity to prevent batteries
> from being created in situations where they are unnecessary.
> 
> There are two cases in particular where batteries are being unnecessarily
> created at initialization. These are AES sensors (for which we don't know
> any battery status information until a battery-powered pen actually comes
> into prox) peripheral tablets which share HID descriptors between the
> wired-only and wireless-capable SKUs of a family of devices.
> 
> This patch will delay battery initialization of the former until a pen
> actually comes into prox. It will delay battery initialization of the
> latter until either a pen comes into prox or a "heartbeat" packet is
> processed.
> 
> Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
> Tested-by: Mario Limonciello <mario.limonciello@amd.com>

Some other tags to add:

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217062
Link: https://gitlab.gnome.org/GNOME/gnome-control-center/-/issues/2354

> ---
>  drivers/hid/wacom_sys.c | 10 ----------
>  drivers/hid/wacom_wac.c | 13 ++++++-------
>  2 files changed, 6 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
> index fb538a6c4add8..8214896adadad 100644
> --- a/drivers/hid/wacom_sys.c
> +++ b/drivers/hid/wacom_sys.c
> @@ -2372,13 +2372,6 @@ static int wacom_parse_and_register(struct
> wacom *wacom, bool wireless)
>  	if (error)
>  		goto fail;
> 
> -	if (!(features->device_type & WACOM_DEVICETYPE_WL_MONITOR)
> &&
> -	     (features->quirks & WACOM_QUIRK_BATTERY)) {
> -		error = wacom_initialize_battery(wacom);
> -		if (error)
> -			goto fail;
> -	}
> -
>  	error = wacom_register_inputs(wacom);
>  	if (error)
>  		goto fail;
> @@ -2509,9 +2502,6 @@ static void wacom_wireless_work(struct
> work_struct *work)
> 
>  		strscpy(wacom_wac->name, wacom_wac1->name,
>  			sizeof(wacom_wac->name));
> -		error = wacom_initialize_battery(wacom);
> -		if (error)
> -			goto fail;
>  	}
> 
>  	return;
> diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
> index 4cfa51416dbcb..391fde5bf6024 100644
> --- a/drivers/hid/wacom_wac.c
> +++ b/drivers/hid/wacom_wac.c
> @@ -113,6 +113,11 @@ static void wacom_notify_battery(struct
> wacom_wac *wacom_wac,
>  	bool bat_connected, bool ps_connected)
>  {
>  	struct wacom *wacom = container_of(wacom_wac, struct wacom,
> wacom_wac);
> +	bool bat_initialized = wacom->battery.battery;
> +	bool has_quirk = wacom_wac->features.quirks &
> WACOM_QUIRK_BATTERY;
> +
> +	if (bat_initialized != has_quirk)
> +		wacom_schedule_work(wacom_wac,
> WACOM_WORKER_BATTERY);
> 
>  	__wacom_notify_battery(&wacom->battery, bat_status,
> bat_capacity,
>  			       bat_charging, bat_connected, ps_connected);
> @@ -3391,19 +3396,13 @@ static int wacom_status_irq(struct wacom_wac
> *wacom_wac, size_t len)
>  		int battery = (data[8] & 0x3f) * 100 / 31;
>  		bool charging = !!(data[8] & 0x80);
> 
> +		features->quirks |= WACOM_QUIRK_BATTERY;
>  		wacom_notify_battery(wacom_wac,
> WACOM_POWER_SUPPLY_STATUS_AUTO,
>  				     battery, charging, battery || charging, 1);
> -
> -		if (!wacom->battery.battery &&
> -		    !(features->quirks & WACOM_QUIRK_BATTERY)) {
> -			features->quirks |= WACOM_QUIRK_BATTERY;
> -			wacom_schedule_work(wacom_wac,
> WACOM_WORKER_BATTERY);
> -		}
>  	}
>  	else if ((features->quirks & WACOM_QUIRK_BATTERY) &&
>  		 wacom->battery.battery) {
>  		features->quirks &= ~WACOM_QUIRK_BATTERY;
> -		wacom_schedule_work(wacom_wac,
> WACOM_WORKER_BATTERY);
>  		wacom_notify_battery(wacom_wac,
> POWER_SUPPLY_STATUS_UNKNOWN, 0, 0, 0, 0);
>  	}
>  	return 0;
> --
> 2.40.0

On Thu, 13 Apr 2023, Jason Gerecke wrote:

> From: Jason Gerecke <killertofu@gmail.com>
> 
> Rather than creating batteries as part of the initial device probe, let's
> make the process lazy. This gives us the opportunity to prevent batteries
> from being created in situations where they are unnecessary.
> 
> There are two cases in particular where batteries are being unnecessarily
> created at initialization. These are AES sensors (for which we don't know
> any battery status information until a battery-powered pen actually comes
> into prox) peripheral tablets which share HID descriptors between the
> wired-only and wireless-capable SKUs of a family of devices.
> 
> This patch will delay battery initialization of the former until a pen
> actually comes into prox. It will delay battery initialization of the
> latter until either a pen comes into prox or a "heartbeat" packet is
> processed.
> 
> Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
> Tested-by: Mario Limonciello <mario.limonciello@amd.com>

I have added the Link: tags suggested by Mario and applied, thanks.