xref: /openbmc/linux/arch/powerpc/sysdev/fsl_pmc.c (revision 81d7cac4)
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/mod_devicetable.h>
17 #include <linux/of_address.h>
18 #include <linux/platform_device.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 
pmc_suspend_enter(suspend_state_t state)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 
pmc_suspend_valid(suspend_state_t state)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 
pmc_probe(struct platform_device * ofdev)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);
85