LXR linux/arch/powerpc/sysdev/fsl

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