LXR linux/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
  35static 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 */
  44static 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
  57static 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
  75static const struct of_device_id pmc_match[] = {
  76        {
  77                .name = PMC_OBPNAME,
  78        },
  79        {},
  80};
  81MODULE_DEVICE_TABLE(of, pmc_match);
  82
  83static struct platform_driver pmc_driver = {
  84        .driver = {
  85                .name = "pmc",
  86                .of_match_table = pmc_match,
  87        },
  88        .probe          = pmc_probe,
  89};
  90
  91static 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);
 101