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_address.h>
  22#include <linux/of_platform.h>
  23
  24struct 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
  33static struct device *pmc_dev;
  34static struct pmc_regs __iomem *pmc_regs;
  35
  36static 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
  51static int pmc_suspend_valid(suspend_state_t state)
  52{
  53        if (state != PM_SUSPEND_STANDBY)
  54                return 0;
  55        return 1;
  56}
  57
  58static const struct platform_suspend_ops pmc_suspend_ops = {
  59        .valid = pmc_suspend_valid,
  60        .enter = pmc_suspend_enter,
  61};
  62
  63static 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
  74static const struct of_device_id pmc_ids[] = {
  75        { .compatible = "fsl,mpc8548-pmc", },
  76        { .compatible = "fsl,mpc8641d-pmc", },
  77        { },
  78};
  79
  80static struct platform_driver pmc_driver = {
  81        .driver = {
  82                .name = "fsl-pmc",
  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