[PATCH v4 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. Other ASUS devices may use the same usage for something
else, so only handle it on the Zenbook Duo keyboards.

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, only handle the usage on Zenbook Duo keyboards, return
 1 from asus_event() instead of propagating its return value, and
 guard the call with IS_REACHABLE(CONFIG_ACPI_PLATFORM_PROFILE)]
Signed-off-by: Paolo Pisati <p.pisati@gmail.com>
---
 drivers/hid/hid-asus.c | 54 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
index 68211ebe1290..739637f1964a 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"
@@ -117,6 +118,7 @@ enum asus_work_action_type {
 	FN_LOCK_SYNC,
 	BRIGHTNESS_SET,
 	WMI_FAN,
+	PLATFORM_PROFILE_CYCLE,
 };
 
 struct hid_raw_event_data {
@@ -431,6 +433,36 @@ 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;
+
+	if (!IS_REACHABLE(CONFIG_ACPI_PLATFORM_PROFILE))
+		return 0;
+
+	guard(spinlock_irqsave)(&worker->lock);
+
+	/*
+	 * 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)
+			return 0;
+	}
+
+	action = kzalloc_obj(struct asus_work_action, GFP_ATOMIC);
+	if (!action)
+		return -ENOMEM;
+
+	action->type = PLATFORM_PROFILE_CYCLE;
+	INIT_LIST_HEAD(&action->node);
+	asus_worker_schedule(worker, action);
+
+	return 0;
+}
+
 static int asus_kbd_wmi_fan_send(struct asus_drvdata *drvdata, u8 *report_data,
 				 size_t report_size)
 {
@@ -467,6 +499,20 @@ 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) {
+		/* Zenbook Duo Fn+F: cycle the platform profile */
+		if ((drvdata->quirks & QUIRK_ZENBOOK_DUO_KEYBOARD) &&
+		    (usage->hid & HID_USAGE) == 0x9d) {
+			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;
+		}
+
 		hid_warn(hdev, "Unmapped Asus vendor usagepage code 0x%02x\n",
 			 usage->hid & HID_USAGE);
 	}
@@ -773,6 +819,7 @@ 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;
 
 	/*
 	 * Dequeue the next action, if any. Once teardown has begun .removed
@@ -801,6 +848,13 @@ 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