xref: /openbmc/linux/arch/sparc/kernel/pmc.c (revision 263291fa)
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 
35 static 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  */
pmc_swift_idle(void)44 static 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 
pmc_probe(struct platform_device * op)57 static 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 
75 static const struct of_device_id pmc_match[] = {
76 	{
77 		.name = PMC_OBPNAME,
78 	},
79 	{},
80 };
81 MODULE_DEVICE_TABLE(of, pmc_match);
82 
83 static struct platform_driver pmc_driver = {
84 	.driver = {
85 		.name = "pmc",
86 		.of_match_table = pmc_match,
87 	},
88 	.probe		= pmc_probe,
89 };
90 
pmc_init(void)91 static 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