Input: i8042 - Add support for platform filter contexts

Currently the platform filter cannot access any driver-specific state
which forces drivers installing a i8042 filter to have at least some
kind of global pointer for their filter.

Allow callers of i8042_install_filter() to submit a context pointer
which is then passed to the i8042 filter. This frees drivers from the
responsibility of having to manage this global pointer themself.

Also introduce a separate type for the i8042 filter (i8042_filter_t)
so that the function definitions can stay compact.

Tested on a Dell Inspiron 3505.

Reviewed-by: Ilpo Järvinen <[e-mail]>
Acked-by: Dmitry Torokhov <[e-mail]>
Signed-off-by: Armin Wolf <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ilpo Järvinen <[e-mail]>

drivers/input/misc/ideapad_slidebar.c

···
 }
 
 static bool slidebar_i8042_filter(unsigned char data, unsigned char str,
-				  struct serio *port)
+				  struct serio *port, void *context)
 {
 	static bool extended = false;
 
···
 	input_set_capability(slidebar_input_dev, EV_ABS, ABS_X);
 	input_set_abs_params(slidebar_input_dev, ABS_X, 0, 0xff, 0, 0);
 
-	err = i8042_install_filter(slidebar_i8042_filter);
+	err = i8042_install_filter(slidebar_i8042_filter, NULL);
 	if (err) {
 		dev_err(&pdev->dev,
 			"Failed to install i8042 filter: %d\n", err);

drivers/input/serio/i8042.c

···
 static struct notifier_block i8042_kbd_bind_notifier_block;
 
 static bool i8042_handle_data(int irq);
-static bool (*i8042_platform_filter)(unsigned char data, unsigned char str,
-				     struct serio *serio);
+static i8042_filter_t i8042_platform_filter;
+static void *i8042_platform_filter_context;
 
 void i8042_lock_chip(void)
 {
···
 }
 EXPORT_SYMBOL(i8042_unlock_chip);
 
-int i8042_install_filter(bool (*filter)(unsigned char data, unsigned char str,
-					struct serio *serio))
+int i8042_install_filter(i8042_filter_t filter, void *context)
 {
 	guard(spinlock_irqsave)(&i8042_lock);
 
···
 		return -EBUSY;
 
 	i8042_platform_filter = filter;
+	i8042_platform_filter_context = context;
 	return 0;
 }
 EXPORT_SYMBOL(i8042_install_filter);
 
-int i8042_remove_filter(bool (*filter)(unsigned char data, unsigned char str,
-				       struct serio *port))
+int i8042_remove_filter(i8042_filter_t filter)
 {
 	guard(spinlock_irqsave)(&i8042_lock);
 
···
 		return -EINVAL;
 
 	i8042_platform_filter = NULL;
+	i8042_platform_filter_context = NULL;
 	return 0;
 }
 EXPORT_SYMBOL(i8042_remove_filter);
···
 		}
 	}
 
-	if (i8042_platform_filter && i8042_platform_filter(data, str, serio)) {
+	if (!i8042_platform_filter)
+		return false;
+
+	if (i8042_platform_filter(data, str, serio, i8042_platform_filter_context)) {
 		dbg("Filtered out by platform filter\n");
 		return true;
 	}

drivers/platform/x86/asus-nb-wmi.c

···
 static struct quirk_entry *quirks;
 static bool atkbd_reports_vol_keys;
 
-static bool asus_i8042_filter(unsigned char data, unsigned char str, struct serio *port)
+static bool asus_i8042_filter(unsigned char data, unsigned char str, struct serio *port,
+			      void *context)
 {
 	static bool extended_e0;
 	static bool extended_e1;

drivers/platform/x86/asus-wmi.c

···
 	}
 
 	if (asus->driver->i8042_filter) {
-		err = i8042_install_filter(asus->driver->i8042_filter);
+		err = i8042_install_filter(asus->driver->i8042_filter, NULL);
 		if (err)
 			pr_warn("Unable to install key filter - %d\n", err);
 	}

drivers/platform/x86/asus-wmi.h

···
 	void (*key_filter) (struct asus_wmi_driver *driver, int *code,
 			    unsigned int *value, bool *autorelease);
 	/* Optional standard i8042 filter */
-	bool (*i8042_filter)(unsigned char data, unsigned char str,
-			     struct serio *serio);
+	i8042_filter_t		i8042_filter;
 
 	int (*probe) (struct platform_device *device);
 	void (*detect_quirks) (struct asus_wmi_driver *driver);

drivers/platform/x86/dell/dell-laptop.c

···
 }
 static DECLARE_DELAYED_WORK(dell_rfkill_work, dell_update_rfkill);
 
-static bool dell_laptop_i8042_filter(unsigned char data, unsigned char str,
-			      struct serio *port)
+static bool dell_laptop_i8042_filter(unsigned char data, unsigned char str, struct serio *port,
+				     void *context)
 {
 	static bool extended;
 
···
 		pr_warn("Unable to register dell rbtn notifier\n");
 		goto err_filter;
 	} else {
-		ret = i8042_install_filter(dell_laptop_i8042_filter);
+		ret = i8042_install_filter(dell_laptop_i8042_filter, NULL);
 		if (ret) {
 			pr_warn("Unable to install key filter\n");
 			goto err_filter;

drivers/platform/x86/hp/hp_accel.c

···
 };
 
 static bool hp_accel_i8042_filter(unsigned char data, unsigned char str,
-				  struct serio *port)
+				  struct serio *port, void *context)
 {
 	static bool extended;
 
···
 	/* filter to remove HPQ6000 accelerometer data
 	 * from keyboard bus stream */
 	if (strstr(dev_name(&device->dev), "HPQ6000"))
-		i8042_install_filter(hp_accel_i8042_filter);
+		i8042_install_filter(hp_accel_i8042_filter, NULL);
 
 	INIT_WORK(&hpled_led.work, delayed_set_status_worker);
 	ret = led_classdev_register(NULL, &hpled_led.led_classdev);

drivers/platform/x86/msi-laptop.c

···
 }
 static DECLARE_DELAYED_WORK(msi_touchpad_dwork, msi_send_touchpad_key);
 
-static bool msi_laptop_i8042_filter(unsigned char data, unsigned char str,
-				struct serio *port)
+static bool msi_laptop_i8042_filter(unsigned char data, unsigned char str, struct serio *port,
+				    void *context)
 {
 	static bool extended;
 
···
 	if (result)
 		goto fail_input;
 
-	result = i8042_install_filter(msi_laptop_i8042_filter);
+	result = i8042_install_filter(msi_laptop_i8042_filter, NULL);
 	if (result) {
 		pr_err("Unable to install key filter\n");
 		goto fail_filter;

drivers/platform/x86/panasonic-laptop.c

···
  * keypress events over the PS/2 kbd interface, filter these out.
  */
 static bool panasonic_i8042_filter(unsigned char data, unsigned char str,
-				   struct serio *port)
+				   struct serio *port, void *context)
 {
 	static bool extended;
 
···
 		pcc->platform = NULL;
 	}
 
-	i8042_install_filter(panasonic_i8042_filter);
+	i8042_install_filter(panasonic_i8042_filter, NULL);
 	return 0;
 
 out_platform:

drivers/platform/x86/toshiba_acpi.c

···
 }
 
 static bool toshiba_acpi_i8042_filter(unsigned char data, unsigned char str,
-				      struct serio *port)
+				      struct serio *port, void *context)
 {
 	if (str & I8042_STR_AUXDATA)
 		return false;
···
 	if (ec_handle && acpi_has_method(ec_handle, "NTFY")) {
 		INIT_WORK(&dev->hotkey_work, toshiba_acpi_hotkey_work);
 
-		error = i8042_install_filter(toshiba_acpi_i8042_filter);
+		error = i8042_install_filter(toshiba_acpi_i8042_filter, NULL);
 		if (error) {
 			pr_err("Error installing key filter\n");
 			goto err_free_dev;

include/linux/i8042.h

···
 
 struct serio;
 
+/**
+ * typedef i8042_filter_t - i8042 filter callback
+ * @data: Data received by the i8042 controller
+ * @str: Status register of the i8042 controller
+ * @serio: Serio of the i8042 controller
+ * @context: Context pointer associated with this callback
+ *
+ * This represents a i8042 filter callback which can be used with i8042_install_filter()
+ * and i8042_remove_filter() to filter the i8042 input for platform-specific key codes.
+ *
+ * Context: Interrupt context.
+ * Returns: true if the data should be filtered out, false if otherwise.
+ */
+typedef bool (*i8042_filter_t)(unsigned char data, unsigned char str, struct serio *serio,
+			       void *context);
+
 #if defined(CONFIG_SERIO_I8042) || defined(CONFIG_SERIO_I8042_MODULE)
 
 void i8042_lock_chip(void);
 void i8042_unlock_chip(void);
 int i8042_command(unsigned char *param, int command);
-int i8042_install_filter(bool (*filter)(unsigned char data, unsigned char str,
-					struct serio *serio));
-int i8042_remove_filter(bool (*filter)(unsigned char data, unsigned char str,
-				       struct serio *serio));
+int i8042_install_filter(i8042_filter_t filter, void *context);
+int i8042_remove_filter(i8042_filter_t filter);
 
 #else
 
···
 	return -ENODEV;
 }
 
-static inline int i8042_install_filter(bool (*filter)(unsigned char data, unsigned char str,
-					struct serio *serio))
+static inline int i8042_install_filter(i8042_filter_t filter, void *context)
 {
 	return -ENODEV;
 }
 
-static inline int i8042_remove_filter(bool (*filter)(unsigned char data, unsigned char str,
-				       struct serio *serio))
+static inline int i8042_remove_filter(i8042_filter_t filter)
 {
 	return -ENODEV;
 }