arch/sparc/kernel/pmc.c

   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 #include <linux/module.h>
  15
  16 #include <asm/io.h>
  17 #include <asm/oplib.h>
  18 #include <linux/uaccess.h>
  19 #include <asm/auxio.h>
  20 #include <asm/processor.h>
  21
  22 /* Debug
  23  *
  24  * #define PMC_DEBUG_LED
  25  * #define PMC_NO_IDLE
  26  */
  27
  28 #define PMC_OBPNAME     "SUNW,pmc"
  29 #define PMC_DEVNAME     "pmc"
  30
  31 #define PMC_IDLE_REG    0x00
  32 #define PMC_IDLE_ON     0x01
  33
  34 static u8 __iomem *regs;
  35
  36 #define pmc_readb(offs)         (sbus_readb(regs+offs))
  37 #define pmc_writeb(val, offs)   (sbus_writeb(val, regs+offs))
  38
  39 /*
  40  * CPU idle callback function
  41  * See .../arch/sparc/kernel/process.c
  42  */
  43 static void pmc_swift_idle(void)
  44 {
  45 #ifdef PMC_DEBUG_LED
  46         set_auxio(0x00, AUXIO_LED);
  47 #endif
  48
  49         pmc_writeb(pmc_readb(PMC_IDLE_REG) | PMC_IDLE_ON, PMC_IDLE_REG);
  50
  51 #ifdef PMC_DEBUG_LED
  52         set_auxio(AUXIO_LED, 0x00);
  53 #endif
  54 }
  55
  56 static int pmc_probe(struct platform_device *op)
  57 {
  58         regs = of_ioremap(&op->resource[0], 0,
  59                           resource_size(&op->resource[0]), PMC_OBPNAME);
  60         if (!regs) {
  61                 printk(KERN_ERR "%s: unable to map registers\n", PMC_DEVNAME);
  62                 return -ENODEV;
  63         }
  64
  65 #ifndef PMC_NO_IDLE
  66         /* Assign power management IDLE handler */
  67         sparc_idle = pmc_swift_idle;
  68 #endif
  69
  70         printk(KERN_INFO "%s: power management initialized\n", PMC_DEVNAME);
  71         return 0;
  72 }
  73
  74 static const struct of_device_id pmc_match[] = {
  75         {
  76                 .name = PMC_OBPNAME,
  77         },
  78         {},
  79 };
  80 MODULE_DEVICE_TABLE(of, pmc_match);
  81
  82 static struct platform_driver pmc_driver = {
  83         .driver = {
  84                 .name = "pmc",
  85                 .of_match_table = pmc_match,
  86         },
  87         .probe          = pmc_probe,
  88 };
  89
  90 static int __init pmc_init(void)
  91 {
  92         return platform_driver_register(&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);