arch/sparc/kernel/pmc.c

   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/of_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  */
  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
  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
  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);