LXR linux/drivers/power/reset/axxia-reset.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Reset driver for Axxia devices
   4 *
   5 * Copyright (C) 2014 LSI
   6 */
   7#include <linux/init.h>
   8#include <linux/err.h>
   9#include <linux/io.h>
  10#include <linux/kernel.h>
  11#include <linux/mfd/syscon.h>
  12#include <linux/module.h>
  13#include <linux/notifier.h>
  14#include <linux/of.h>
  15#include <linux/platform_device.h>
  16#include <linux/reboot.h>
  17#include <linux/regmap.h>
  18
  19#define SC_CRIT_WRITE_KEY       0x1000
  20#define SC_LATCH_ON_RESET       0x1004
  21#define SC_RESET_CONTROL        0x1008
  22#define   RSTCTL_RST_ZERO       (1<<3)
  23#define   RSTCTL_RST_FAB        (1<<2)
  24#define   RSTCTL_RST_CHIP       (1<<1)
  25#define   RSTCTL_RST_SYS        (1<<0)
  26#define SC_EFUSE_INT_STATUS     0x180c
  27#define   EFUSE_READ_DONE       (1<<31)
  28
  29static struct regmap *syscon;
  30
  31static int axxia_restart_handler(struct notifier_block *this,
  32                                 unsigned long mode, void *cmd)
  33{
  34        /* Access Key (0xab) */
  35        regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab);
  36        /* Select internal boot from 0xffff0000 */
  37        regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040);
  38        /* Assert ResetReadDone (to avoid hanging in boot ROM) */
  39        regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE);
  40        /* Assert chip reset */
  41        regmap_update_bits(syscon, SC_RESET_CONTROL,
  42                           RSTCTL_RST_CHIP, RSTCTL_RST_CHIP);
  43
  44        return NOTIFY_DONE;
  45}
  46
  47static struct notifier_block axxia_restart_nb = {
  48        .notifier_call = axxia_restart_handler,
  49        .priority = 128,
  50};
  51
  52static int axxia_reset_probe(struct platform_device *pdev)
  53{
  54        struct device *dev = &pdev->dev;
  55        int err;
  56
  57        syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
  58        if (IS_ERR(syscon)) {
  59                pr_err("%pOFn: syscon lookup failed\n", dev->of_node);
  60                return PTR_ERR(syscon);
  61        }
  62
  63        err = register_restart_handler(&axxia_restart_nb);
  64        if (err)
  65                dev_err(dev, "cannot register restart handler (err=%d)\n", err);
  66
  67        return err;
  68}
  69
  70static const struct of_device_id of_axxia_reset_match[] = {
  71        { .compatible = "lsi,axm55xx-reset", },
  72        {},
  73};
  74MODULE_DEVICE_TABLE(of, of_axxia_reset_match);
  75
  76static struct platform_driver axxia_reset_driver = {
  77        .probe = axxia_reset_probe,
  78        .driver = {
  79                .name = "axxia-reset",
  80                .of_match_table = of_match_ptr(of_axxia_reset_match),
  81        },
  82};
  83
  84static int __init axxia_reset_init(void)
  85{
  86        return platform_driver_register(&axxia_reset_driver);
  87}
  88device_initcall(axxia_reset_init);
  89