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
  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 of_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         .name           = "pmc",
  83         .match_table    = pmc_match,
  84         .probe          = pmc_probe,
  85 };
  86
  87 static int __init pmc_init(void)
  88 {
  89         return of_register_driver(&pmc_driver, &of_bus_type);
  90 }
  91
  92 /* This driver is not critical to the boot process
  93  * and is easiest to ioremap when SBus is already
  94  * initialized, so we install ourselves thusly:
  95  */
  96 __initcall(pmc_init);