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/export.h>
  18 #include <linux/suspend.h>
  19 #include <linux/delay.h>
  20 #include <linux/device.h>
  21 #include <linux/of_address.h>
  22 #include <linux/of_platform.h>
  23
  24 struct pmc_regs {
  25         __be32 devdisr;
  26         __be32 devdisr2;
  27         __be32 :32;
  28         __be32 :32;
  29         __be32 pmcsr;
  30 #define PMCSR_SLP       (1 << 17)
  31 };
  32
  33 static struct device *pmc_dev;
  34 static struct pmc_regs __iomem *pmc_regs;
  35
  36 static int pmc_suspend_enter(suspend_state_t state)
  37 {
  38         int ret;
  39
  40         setbits32(&pmc_regs->pmcsr, PMCSR_SLP);
  41         /* At this point, the CPU is asleep. */
  42
  43         /* Upon resume, wait for SLP bit to be clear. */
  44         ret = spin_event_timeout((in_be32(&pmc_regs->pmcsr) & PMCSR_SLP) == 0,
  45                                  10000, 10) ? 0 : -ETIMEDOUT;
  46         if (ret)
  47                 dev_err(pmc_dev, "tired waiting for SLP bit to clear\n");
  48         return ret;
  49 }
  50
  51 static int pmc_suspend_valid(suspend_state_t state)
  52 {
  53         if (state != PM_SUSPEND_STANDBY)
  54                 return 0;
  55         return 1;
  56 }
  57
  58 static const struct platform_suspend_ops pmc_suspend_ops = {
  59         .valid = pmc_suspend_valid,
  60         .enter = pmc_suspend_enter,
  61 };
  62
  63 static int pmc_probe(struct platform_device *ofdev)
  64 {
  65         pmc_regs = of_iomap(ofdev->dev.of_node, 0);
  66         if (!pmc_regs)
  67                 return -ENOMEM;
  68
  69         pmc_dev = &ofdev->dev;
  70         suspend_set_ops(&pmc_suspend_ops);
  71         return 0;
  72 }
  73
  74 static const struct of_device_id pmc_ids[] = {
  75         { .compatible = "fsl,mpc8548-pmc", },
  76         { .compatible = "fsl,mpc8641d-pmc", },
  77         { },
  78 };
  79
  80 static struct platform_driver pmc_driver = {
  81         .driver = {
  82                 .name = "fsl-pmc",
  83                 .owner = THIS_MODULE,
  84                 .of_match_table = pmc_ids,
  85         },
  86         .probe = pmc_probe,
  87 };
  88
  89 static int __init pmc_init(void)
  90 {
  91         return platform_driver_register(&pmc_driver);
  92 }
  93 device_initcall(pmc_init);