[PATCH v3 4/7] HID: asus: Cycle the platform profile from the Zenbook Duo profile key

[Paolo Pisati <p.pisati@gmail.com>]

From: Joshua Leivenzon <hacker1024@users.sourceforge.net>

The Zenbook Duo keyboard reports Fn+F, the performance mode key, as
vendor usage 0x9d. On the built-in keyboards of other ASUS laptops the
same key arrives through asus-wmi, which cycles the platform profile
in response. Do the same here so the key works on the detachable
keyboard too.

asus_event() runs from the HID input path, which for USB is the URB
completion handler, while platform_profile_cycle() takes a mutex, so run
it from the driver's worker like the Fn-lock toggle, and consume the
event. Queue at most one cycle at a time, so that a device repeating the
key cannot grow the worker's list. Only call it when the platform
profile class is reachable: it is not built on architectures without
ACPI, where HID_ASUS still is, and it may be a module while HID_ASUS is
built in.

Signed-off-by: Joshua Leivenzon <hacker1024@users.sourceforge.net>
[pisati: defer platform_profile_cycle() to the worker and queue at
 most one cycle, return 1 from asus_event() instead of propagating
 its return value, and guard the call with
 IS_REACHABLE(CONFIG_ACPI_PLATFORM_PROFILE)]
Assisted-by: LLM
Signed-off-by: Paolo Pisati <p.pisati@gmail.com>
Tested-by: Rebecca Mara Müller <rebecca.mara@posteo.de> # UX8407AA
---
 drivers/hid/hid-asus.c | 67 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 65 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
index d69431615c27..b127f5c38f60 100644
--- a/drivers/hid/hid-asus.c
+++ b/drivers/hid/hid-asus.c
@@ -29,6 +29,7 @@
 #include <linux/input/mt.h>
 #include <linux/usb.h> /* For to_usb_interface for T100 touchpad intf check */
 #include <linux/power_supply.h>
+#include <linux/platform_profile.h>
 #include <linux/leds.h>
 
 #include "hid-ids.h"
@@ -115,6 +116,7 @@ enum asus_work_action_type {
 	FN_LOCK_SYNC,
 	BRIGHTNESS_SET,
 	WMI_FAN,
+	PLATFORM_PROFILE_CYCLE,
 };
 
 struct hid_raw_event_data {
@@ -423,6 +425,42 @@ static int asus_kbd_fn_lock_set(struct asus_drvdata *drvdata, bool enabled)
 	return 0;
 }
 
+static int asus_platform_profile_cycle(struct asus_drvdata *drvdata)
+{
+	struct asus_worker *worker = drvdata->worker;
+	struct asus_work_action *action, *pending;
+	unsigned long flags;
+	int ret = 0;
+
+	if (!IS_REACHABLE(CONFIG_ACPI_PLATFORM_PROFILE))
+		return 0;
+
+	spin_lock_irqsave(&worker->lock, flags);
+
+	/*
+	 * One pending cycle is enough: a key press cannot outrun the
+	 * worker, and a device repeating the key must not grow the list.
+	 */
+	list_for_each_entry(pending, &worker->actions, node) {
+		if (pending->type == PLATFORM_PROFILE_CYCLE)
+			goto unlock;
+	}
+
+	action = kzalloc_obj(struct asus_work_action, GFP_ATOMIC);
+	if (!action) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	action->type = PLATFORM_PROFILE_CYCLE;
+	INIT_LIST_HEAD(&action->node);
+	asus_worker_schedule(worker, action);
+
+unlock:
+	spin_unlock_irqrestore(&worker->lock, flags);
+	return ret;
+}
+
 static int asus_kbd_wmi_fan_send(struct asus_drvdata *drvdata, u8 *report_data,
 				 size_t report_size)
 {
@@ -459,8 +497,25 @@ static int asus_event(struct hid_device *hdev, struct hid_field *field,
 	if ((usage->hid & HID_USAGE_PAGE) == HID_UP_ASUSVENDOR &&
 	    (usage->hid & HID_USAGE) != 0x00 &&
 	    (usage->hid & HID_USAGE) != 0xff && !usage->type) {
-		hid_warn(hdev, "Unmapped Asus vendor usagepage code 0x%02x\n",
-			 usage->hid & HID_USAGE);
+		/*
+		 * Some vendor usages do not map to a key and need special
+		 * handling.
+		 */
+		switch (usage->hid & HID_USAGE) {
+		case 0x9d: /* Zenbook Duo Fn+F: cycle the platform profile */
+			if (value) {
+				ret = asus_platform_profile_cycle(drvdata);
+				if (ret) {
+					hid_err(hdev, "Failed to cycle the platform profile: %d\n",
+						ret);
+					return ret;
+				}
+			}
+			return 1;
+		default:
+			hid_warn(hdev, "Unmapped Asus vendor usagepage code 0x%02x\n",
+				 usage->hid & HID_USAGE);
+		}
 	}
 
 	if (usage->type == EV_KEY && value) {
@@ -765,6 +820,7 @@ static void asus_work(struct work_struct *work)
 	struct asus_worker *worker = container_of(work, struct asus_worker, work);
 	struct asus_work_action *action = NULL;
 	unsigned long flags;
+	int ret;
 
 	/* Save the action to be performed and clear the flag */
 	spin_lock_irqsave(&worker->lock, flags);
@@ -788,6 +844,13 @@ static void asus_work(struct work_struct *work)
 	case WMI_FAN:
 		asus_kbd_wmi_fan(worker->hdev, &action->data.fan_hid_data);
 		break;
+	case PLATFORM_PROFILE_CYCLE:
+		if (!IS_REACHABLE(CONFIG_ACPI_PLATFORM_PROFILE))
+			break;
+		ret = platform_profile_cycle();
+		if (ret)
+			hid_dbg(worker->hdev, "Failed to cycle the platform profile: %d\n", ret);
+		break;
 	default:
 		hid_err(worker->hdev, "Invalid action type: %d\n", action->type);
 		break;
-- 
2.43.0