/* SPDX-License-Identifier: GPL-2.0-only */
  /*
   * apple-gmux.h - microcontroller built into dual GPU MacBook Pro & Mac Pro
   * Copyright (C) 2015 Lukas Wunner <lukas@wunner.de>
   */
  
  #ifndef LINUX_APPLE_GMUX_H
  #define LINUX_APPLE_GMUX_H
  
  #include <linux/acpi.h>
  
  #define GMUX_ACPI_HID "APP000B"
  
  #if IS_ENABLED(CONFIG_APPLE_GMUX)
  
  /**
   * apple_gmux_present() - detect if gmux is built into the machine
   *
   * Drivers may use this to activate quirks specific to dual GPU MacBook Pros
   * and Mac Pros, e.g. for deferred probing, runtime pm and backlight.
   *
   * Return: %true if gmux is present and the kernel was configured
   * with CONFIG_APPLE_GMUX, %false otherwise.
   */
  static inline bool apple_gmux_present(void)
  {
  	return acpi_dev_found(GMUX_ACPI_HID);
  }
  
  #else  /* !CONFIG_APPLE_GMUX */
  
  static inline bool apple_gmux_present(void)
  {
  	return false;
  }
  
  #endif /* !CONFIG_APPLE_GMUX */
  
  #endif /* LINUX_APPLE_GMUX_H */