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 platform_device *op)
  55 {
  56         regs = of_ioremap(&op->resource[0], 0,
  57                           resource_size(&op->resource[0]), PMC_OBPNAME);
  58         if (!regs) {
  59                 printk(KERN_ERR "%s: unable to map registers\n", PMC_DEVNAME);
  60                 return -ENODEV;
  61         }
  62
  63 #ifndef PMC_NO_IDLE
  64         /* Assign power management IDLE handler */
  65         pm_idle = pmc_swift_idle;
  66 #endif
  67
  68         printk(KERN_INFO "%s: power management initialized\n", PMC_DEVNAME);
  69         return 0;
  70 }
  71
  72 static struct of_device_id __initdata pmc_match[] = {
  73         {
  74                 .name = PMC_OBPNAME,
  75         },
  76         {},
  77 };
  78 MODULE_DEVICE_TABLE(of, pmc_match);
  79
  80 static struct platform_driver pmc_driver = {
  81         .driver = {
  82                 .name = "pmc",
  83                 .owner = THIS_MODULE,
  84                 .of_match_table = pmc_match,
  85         },
  86         .probe          = pmc_probe,
  87 };
  88
  89 static int __init pmc_init(void)
  90 {
  91         return platform_driver_register(&pmc_driver);
  92 }
  93
  94 /* This driver is not critical to the boot process
  95  * and is easiest to ioremap when SBus is already
  96  * initialized, so we install ourselves thusly:
  97  */
  98 __initcall(pmc_init);