arch/powerpc/sysdev/fsl_pmc.c

   1 /*
   2  * Suspend/resume support
   3  *
   4  * Copyright 2009  MontaVista Software, Inc.
   5  *
   6  * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  */
  13
  14 #include <linux/init.h>
  15 #include <linux/types.h>
  16 #include <linux/errno.h>
  17 #include <linux/suspend.h>
  18 #include <linux/delay.h>
  19 #include <linux/device.h>
  20 #include <linux/of_platform.h>
  21
  22 struct pmc_regs {
  23         __be32 devdisr;
  24         __be32 devdisr2;
  25         __be32 :32;
  26         __be32 :32;
  27         __be32 pmcsr;
  28 #define PMCSR_SLP       (1 << 17)
  29 };
  30
  31 static struct device *pmc_dev;
  32 static struct pmc_regs __iomem *pmc_regs;
  33
  34 static int pmc_suspend_enter(suspend_state_t state)
  35 {
  36         int ret;
  37
  38         setbits32(&pmc_regs->pmcsr, PMCSR_SLP);
  39         /* At this point, the CPU is asleep. */
  40
  41         /* Upon resume, wait for SLP bit to be clear. */
  42         ret = spin_event_timeout((in_be32(&pmc_regs->pmcsr) & PMCSR_SLP) == 0,
  43                                  10000, 10) ? 0 : -ETIMEDOUT;
  44         if (ret)
  45                 dev_err(pmc_dev, "tired waiting for SLP bit to clear\n");
  46         return ret;
  47 }
  48
  49 static int pmc_suspend_valid(suspend_state_t state)
  50 {
  51         if (state != PM_SUSPEND_STANDBY)
  52                 return 0;
  53         return 1;
  54 }
  55
  56 static struct platform_suspend_ops pmc_suspend_ops = {
  57         .valid = pmc_suspend_valid,
  58         .enter = pmc_suspend_enter,
  59 };
  60
  61 static int pmc_probe(struct of_device *ofdev, const struct of_device_id *id)
  62 {
  63         pmc_regs = of_iomap(ofdev->dev.of_node, 0);
  64         if (!pmc_regs)
  65                 return -ENOMEM;
  66
  67         pmc_dev = &ofdev->dev;
  68         suspend_set_ops(&pmc_suspend_ops);
  69         return 0;
  70 }
  71
  72 static const struct of_device_id pmc_ids[] = {
  73         { .compatible = "fsl,mpc8548-pmc", },
  74         { .compatible = "fsl,mpc8641d-pmc", },
  75         { },
  76 };
  77
  78 static struct of_platform_driver pmc_driver = {
  79         .driver = {
  80                 .name = "fsl-pmc",
  81                 .owner = THIS_MODULE,
  82                 .of_match_table = pmc_ids,
  83         },
  84         .probe = pmc_probe,
  85 };
  86
  87 static int __init pmc_init(void)
  88 {
  89         return of_register_platform_driver(&pmc_driver);
  90 }
  91 device_initcall(pmc_init);