arch/powerpc/sysdev/fsl_pmc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Suspend/resume support
   4  *
   5  * Copyright 2009  MontaVista Software, Inc.
   6  *
   7  * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/types.h>
  12 #include <linux/errno.h>
  13 #include <linux/export.h>
  14 #include <linux/suspend.h>
  15 #include <linux/delay.h>
  16 #include <linux/device.h>
  17 #include <linux/of_address.h>
  18 #include <linux/of_platform.h>
  19
  20 struct pmc_regs {
  21         __be32 devdisr;
  22         __be32 devdisr2;
  23         __be32 :32;
  24         __be32 :32;
  25         __be32 pmcsr;
  26 #define PMCSR_SLP       (1 << 17)
  27 };
  28
  29 static struct device *pmc_dev;
  30 static struct pmc_regs __iomem *pmc_regs;
  31
  32 static int pmc_suspend_enter(suspend_state_t state)
  33 {
  34         int ret;
  35
  36         setbits32(&pmc_regs->pmcsr, PMCSR_SLP);
  37         /* At this point, the CPU is asleep. */
  38
  39         /* Upon resume, wait for SLP bit to be clear. */
  40         ret = spin_event_timeout((in_be32(&pmc_regs->pmcsr) & PMCSR_SLP) == 0,
  41                                  10000, 10) ? 0 : -ETIMEDOUT;
  42         if (ret)
  43                 dev_err(pmc_dev, "tired waiting for SLP bit to clear\n");
  44         return ret;
  45 }
  46
  47 static int pmc_suspend_valid(suspend_state_t state)
  48 {
  49         if (state != PM_SUSPEND_STANDBY)
  50                 return 0;
  51         return 1;
  52 }
  53
  54 static const struct platform_suspend_ops pmc_suspend_ops = {
  55         .valid = pmc_suspend_valid,
  56         .enter = pmc_suspend_enter,
  57 };
  58
  59 static int pmc_probe(struct platform_device *ofdev)
  60 {
  61         pmc_regs = of_iomap(ofdev->dev.of_node, 0);
  62         if (!pmc_regs)
  63                 return -ENOMEM;
  64
  65         pmc_dev = &ofdev->dev;
  66         suspend_set_ops(&pmc_suspend_ops);
  67         return 0;
  68 }
  69
  70 static const struct of_device_id pmc_ids[] = {
  71         { .compatible = "fsl,mpc8548-pmc", },
  72         { .compatible = "fsl,mpc8641d-pmc", },
  73         { },
  74 };
  75
  76 static struct platform_driver pmc_driver = {
  77         .driver = {
  78                 .name = "fsl-pmc",
  79                 .of_match_table = pmc_ids,
  80         },
  81         .probe = pmc_probe,
  82 };
  83
  84 builtin_platform_driver(pmc_driver);