1// SPDX-License-Identifier: GPL-2.0
2/* pmc - Driver implementation for power management functions
3 * of Power Management Controller (PMC) on SPARCstation-Voyager.
4 *
5 * Copyright (c) 2002 Eric Brower (ebrower@usa.net)
6 */
7
8#include <linux/kernel.h>
9#include <linux/fs.h>
10#include <linux/errno.h>
11#include <linux/init.h>
12#include <linux/pm.h>
13#include <linux/of.h>
14#include <linux/platform_device.h>
15#include <linux/module.h>
16
17#include <asm/io.h>
18#include <asm/oplib.h>
19#include <linux/uaccess.h>
20#include <asm/auxio.h>
21#include <asm/processor.h>
22
23/* Debug
24 *
25 * #define PMC_DEBUG_LED
26 * #define PMC_NO_IDLE
27 */
28
29#define PMC_OBPNAME	"SUNW,pmc"
30#define PMC_DEVNAME	"pmc"
31
32#define PMC_IDLE_REG	0x00
33#define PMC_IDLE_ON	0x01
34
35static u8 __iomem *regs;
36
37#define pmc_readb(offs)		(sbus_readb(regs+offs))
38#define pmc_writeb(val, offs)	(sbus_writeb(val, regs+offs))
39
40/*
41 * CPU idle callback function
42 * See .../arch/sparc/kernel/process.c
43 */
44static void pmc_swift_idle(void)
45{
46#ifdef PMC_DEBUG_LED
47	set_auxio(0x00, AUXIO_LED);
48#endif
49
50	pmc_writeb(pmc_readb(PMC_IDLE_REG) | PMC_IDLE_ON, PMC_IDLE_REG);
51
52#ifdef PMC_DEBUG_LED
53	set_auxio(AUXIO_LED, 0x00);
54#endif
55}
56
57static int pmc_probe(struct platform_device *op)
58{
59	regs = of_ioremap(&op->resource[0], 0,
60			  resource_size(&op->resource[0]), PMC_OBPNAME);
61	if (!regs) {
62		printk(KERN_ERR "%s: unable to map registers\n", PMC_DEVNAME);
63		return -ENODEV;
64	}
65
66#ifndef PMC_NO_IDLE
67	/* Assign power management IDLE handler */
68	sparc_idle = pmc_swift_idle;
69#endif
70
71	printk(KERN_INFO "%s: power management initialized\n", PMC_DEVNAME);
72	return 0;
73}
74
75static const struct of_device_id pmc_match[] = {
76	{
77		.name = PMC_OBPNAME,
78	},
79	{},
80};
81MODULE_DEVICE_TABLE(of, pmc_match);
82
83static struct platform_driver pmc_driver = {
84	.driver = {
85		.name = "pmc",
86		.of_match_table = pmc_match,
87	},
88	.probe		= pmc_probe,
89};
90
91static int __init pmc_init(void)
92{
93	return platform_driver_register(&pmc_driver);
94}
95
96/* This driver is not critical to the boot process
97 * and is easiest to ioremap when SBus is already
98 * initialized, so we install ourselves thusly:
99 */
100__initcall(pmc_init);
101