LXR linux/drivers/cpuidle/cpuidle-at91.c

   1/*
   2 * based on arch/arm/mach-kirkwood/cpuidle.c
   3 *
   4 * CPU idle support for AT91 SoC
   5 *
   6 * This file is licensed under the terms of the GNU General Public
   7 * License version 2.  This program is licensed "as is" without any
   8 * warranty of any kind, whether express or implied.
   9 *
  10 * The cpu idle uses wait-for-interrupt and RAM self refresh in order
  11 * to implement two idle states -
  12 * #1 wait-for-interrupt
  13 * #2 wait-for-interrupt and RAM self refresh
  14 */
  15
  16#include <linux/kernel.h>
  17#include <linux/init.h>
  18#include <linux/platform_device.h>
  19#include <linux/cpuidle.h>
  20#include <linux/io.h>
  21#include <linux/export.h>
  22#include <asm/cpuidle.h>
  23
  24#define AT91_MAX_STATES 2
  25
  26static void (*at91_standby)(void);
  27
  28/* Actual code that puts the SoC in different idle states */
  29static int at91_enter_idle(struct cpuidle_device *dev,
  30                        struct cpuidle_driver *drv,
  31                               int index)
  32{
  33        at91_standby();
  34        return index;
  35}
  36
  37static struct cpuidle_driver at91_idle_driver = {
  38        .name                   = "at91_idle",
  39        .owner                  = THIS_MODULE,
  40        .states[0]              = ARM_CPUIDLE_WFI_STATE,
  41        .states[1]              = {
  42                .enter                  = at91_enter_idle,
  43                .exit_latency           = 10,
  44                .target_residency       = 10000,
  45                .name                   = "RAM_SR",
  46                .desc                   = "WFI and DDR Self Refresh",
  47        },
  48        .state_count = AT91_MAX_STATES,
  49};
  50
  51/* Initialize CPU idle by registering the idle states */
  52static int at91_cpuidle_probe(struct platform_device *dev)
  53{
  54        at91_standby = (void *)(dev->dev.platform_data);
  55        
  56        return cpuidle_register(&at91_idle_driver, NULL);
  57}
  58
  59static struct platform_driver at91_cpuidle_driver = {
  60        .driver = {
  61                .name = "cpuidle-at91",
  62        },
  63        .probe = at91_cpuidle_probe,
  64};
  65builtin_platform_driver(at91_cpuidle_driver);
  66