xref: /openbmc/linux/arch/sparc/kernel/pmc.c (revision df2634f43f5106947f3735a0b61a6527a4b278cd)
1 /* pmc - Driver implementation for power management functions
2  * of Power Management Controller (PMC) on SPARCstation-Voyager.
3  *
4  * Copyright (c) 2002 Eric Brower (ebrower@usa.net)
5  */
6 
7 #include <linux/kernel.h>
8 #include <linux/fs.h>
9 #include <linux/errno.h>
10 #include <linux/init.h>
11 #include <linux/pm.h>
12 #include <linux/of.h>
13 #include <linux/of_device.h>
14 
15 #include <asm/io.h>
16 #include <asm/oplib.h>
17 #include <asm/uaccess.h>
18 #include <asm/auxio.h>
19 
20 /* Debug
21  *
22  * #define PMC_DEBUG_LED
23  * #define PMC_NO_IDLE
24  */
25 
26 #define PMC_OBPNAME	"SUNW,pmc"
27 #define PMC_DEVNAME	"pmc"
28 
29 #define PMC_IDLE_REG	0x00
30 #define PMC_IDLE_ON	0x01
31 
32 static u8 __iomem *regs;
33 
34 #define pmc_readb(offs)		(sbus_readb(regs+offs))
35 #define pmc_writeb(val, offs)	(sbus_writeb(val, regs+offs))
36 
37 /*
38  * CPU idle callback function
39  * See .../arch/sparc/kernel/process.c
40  */
41 static void pmc_swift_idle(void)
42 {
43 #ifdef PMC_DEBUG_LED
44 	set_auxio(0x00, AUXIO_LED);
45 #endif
46 
47 	pmc_writeb(pmc_readb(PMC_IDLE_REG) | PMC_IDLE_ON, PMC_IDLE_REG);
48 
49 #ifdef PMC_DEBUG_LED
50 	set_auxio(AUXIO_LED, 0x00);
51 #endif
52 }
53 
54 static int __devinit pmc_probe(struct platform_device *op,
55 			       const struct of_device_id *match)
56 {
57 	regs = of_ioremap(&op->resource[0], 0,
58 			  resource_size(&op->resource[0]), PMC_OBPNAME);
59 	if (!regs) {
60 		printk(KERN_ERR "%s: unable to map registers\n", PMC_DEVNAME);
61 		return -ENODEV;
62 	}
63 
64 #ifndef PMC_NO_IDLE
65 	/* Assign power management IDLE handler */
66 	pm_idle = pmc_swift_idle;
67 #endif
68 
69 	printk(KERN_INFO "%s: power management initialized\n", PMC_DEVNAME);
70 	return 0;
71 }
72 
73 static struct of_device_id __initdata pmc_match[] = {
74 	{
75 		.name = PMC_OBPNAME,
76 	},
77 	{},
78 };
79 MODULE_DEVICE_TABLE(of, pmc_match);
80 
81 static struct of_platform_driver pmc_driver = {
82 	.driver = {
83 		.name = "pmc",
84 		.owner = THIS_MODULE,
85 		.of_match_table = pmc_match,
86 	},
87 	.probe		= pmc_probe,
88 };
89 
90 static int __init pmc_init(void)
91 {
92 	return of_register_platform_driver(&pmc_driver);
93 }
94 
95 /* This driver is not critical to the boot process
96  * and is easiest to ioremap when SBus is already
97  * initialized, so we install ourselves thusly:
98  */
99 __initcall(pmc_init);
100