/*
   * based on arch/arm/mach-kirkwood/cpuidle.c
   *
   * CPU idle support for AT91 SoC
   *
   * This file is licensed under the terms of the GNU General Public
   * License version 2.  This program is licensed "as is" without any
   * warranty of any kind, whether express or implied.
   *
   * The cpu idle uses wait-for-interrupt and RAM self refresh in order
   * to implement two idle states -
   * #1 wait-for-interrupt
   * #2 wait-for-interrupt and RAM self refresh
   */
  
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/platform_device.h>
  #include <linux/cpuidle.h>
  #include <linux/io.h>
  #include <linux/export.h>
  #include <asm/cpuidle.h>
  
  #define AT91_MAX_STATES	2
  
  static void (*at91_standby)(void);
  
  /* Actual code that puts the SoC in different idle states */
  static int at91_enter_idle(struct cpuidle_device *dev,
  			struct cpuidle_driver *drv,
  			       int index)
  {
  	at91_standby();
  	return index;
  }
  
  static struct cpuidle_driver at91_idle_driver = {
  	.name			= "at91_idle",
  	.owner			= THIS_MODULE,
  	.states[0]		= ARM_CPUIDLE_WFI_STATE,
  	.states[1]		= {
  		.enter			= at91_enter_idle,
  		.exit_latency		= 10,
  		.target_residency	= 10000,
  		.name			= "RAM_SR",
  		.desc			= "WFI and DDR Self Refresh",
  	},
  	.state_count = AT91_MAX_STATES,
  };
  
  /* Initialize CPU idle by registering the idle states */
  static int at91_cpuidle_probe(struct platform_device *dev)
  {
  	at91_standby = (void *)(dev->dev.platform_data);
  	
  	return cpuidle_register(&at91_idle_driver, NULL);
  }
  
  static struct platform_driver at91_cpuidle_driver = {
  	.driver = {
  		.name = "cpuidle-at91",
  	},
  	.probe = at91_cpuidle_probe,
  };
  builtin_platform_driver(at91_cpuidle_driver);