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 23 struct 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 32 static struct device *pmc_dev; 33 static struct pmc_regs __iomem *pmc_regs; 34 35 static 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 50 static int pmc_suspend_valid(suspend_state_t state) 51 { 52 if (state != PM_SUSPEND_STANDBY) 53 return 0; 54 return 1; 55 } 56 57 static const struct platform_suspend_ops pmc_suspend_ops = { 58 .valid = pmc_suspend_valid, 59 .enter = pmc_suspend_enter, 60 }; 61 62 static 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 73 static const struct of_device_id pmc_ids[] = { 74 { .compatible = "fsl,mpc8548-pmc", }, 75 { .compatible = "fsl,mpc8641d-pmc", }, 76 { }, 77 }; 78 79 static 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 88 static int __init pmc_init(void) 89 { 90 return platform_driver_register(&pmc_driver); 91 } 92 device_initcall(pmc_init); 93