LXR linux/drivers/reset/reset-ath79.c

   1/*
   2 * AR71xx Reset Controller Driver
   3 * Author: Alban Bedel
   4 *
   5 * Copyright (C) 2015 Alban Bedel <albeu@free.fr>
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License as published by
   9 * the Free Software Foundation; either version 2 of the License, or
  10 * (at your option) any later version.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 */
  17
  18#include <linux/io.h>
  19#include <linux/init.h>
  20#include <linux/platform_device.h>
  21#include <linux/reset-controller.h>
  22#include <linux/reboot.h>
  23
  24struct ath79_reset {
  25        struct reset_controller_dev rcdev;
  26        struct notifier_block restart_nb;
  27        void __iomem *base;
  28        spinlock_t lock;
  29};
  30
  31#define FULL_CHIP_RESET 24
  32
  33static int ath79_reset_update(struct reset_controller_dev *rcdev,
  34                        unsigned long id, bool assert)
  35{
  36        struct ath79_reset *ath79_reset =
  37                container_of(rcdev, struct ath79_reset, rcdev);
  38        unsigned long flags;
  39        u32 val;
  40
  41        spin_lock_irqsave(&ath79_reset->lock, flags);
  42        val = readl(ath79_reset->base);
  43        if (assert)
  44                val |= BIT(id);
  45        else
  46                val &= ~BIT(id);
  47        writel(val, ath79_reset->base);
  48        spin_unlock_irqrestore(&ath79_reset->lock, flags);
  49
  50        return 0;
  51}
  52
  53static int ath79_reset_assert(struct reset_controller_dev *rcdev,
  54                        unsigned long id)
  55{
  56        return ath79_reset_update(rcdev, id, true);
  57}
  58
  59static int ath79_reset_deassert(struct reset_controller_dev *rcdev,
  60                                unsigned long id)
  61{
  62        return ath79_reset_update(rcdev, id, false);
  63}
  64
  65static int ath79_reset_status(struct reset_controller_dev *rcdev,
  66                        unsigned long id)
  67{
  68        struct ath79_reset *ath79_reset =
  69                container_of(rcdev, struct ath79_reset, rcdev);
  70        u32 val;
  71
  72        val = readl(ath79_reset->base);
  73
  74        return !!(val & BIT(id));
  75}
  76
  77static const struct reset_control_ops ath79_reset_ops = {
  78        .assert = ath79_reset_assert,
  79        .deassert = ath79_reset_deassert,
  80        .status = ath79_reset_status,
  81};
  82
  83static int ath79_reset_restart_handler(struct notifier_block *nb,
  84                                unsigned long action, void *data)
  85{
  86        struct ath79_reset *ath79_reset =
  87                container_of(nb, struct ath79_reset, restart_nb);
  88
  89        ath79_reset_assert(&ath79_reset->rcdev, FULL_CHIP_RESET);
  90
  91        return NOTIFY_DONE;
  92}
  93
  94static int ath79_reset_probe(struct platform_device *pdev)
  95{
  96        struct ath79_reset *ath79_reset;
  97        struct resource *res;
  98        int err;
  99
 100        ath79_reset = devm_kzalloc(&pdev->dev,
 101                                sizeof(*ath79_reset), GFP_KERNEL);
 102        if (!ath79_reset)
 103                return -ENOMEM;
 104
 105        platform_set_drvdata(pdev, ath79_reset);
 106
 107        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 108        ath79_reset->base = devm_ioremap_resource(&pdev->dev, res);
 109        if (IS_ERR(ath79_reset->base))
 110                return PTR_ERR(ath79_reset->base);
 111
 112        spin_lock_init(&ath79_reset->lock);
 113        ath79_reset->rcdev.ops = &ath79_reset_ops;
 114        ath79_reset->rcdev.owner = THIS_MODULE;
 115        ath79_reset->rcdev.of_node = pdev->dev.of_node;
 116        ath79_reset->rcdev.of_reset_n_cells = 1;
 117        ath79_reset->rcdev.nr_resets = 32;
 118
 119        err = devm_reset_controller_register(&pdev->dev, &ath79_reset->rcdev);
 120        if (err)
 121                return err;
 122
 123        ath79_reset->restart_nb.notifier_call = ath79_reset_restart_handler;
 124        ath79_reset->restart_nb.priority = 128;
 125
 126        err = register_restart_handler(&ath79_reset->restart_nb);
 127        if (err)
 128                dev_warn(&pdev->dev, "Failed to register restart handler\n");
 129
 130        return 0;
 131}
 132
 133static const struct of_device_id ath79_reset_dt_ids[] = {
 134        { .compatible = "qca,ar7100-reset", },
 135        { },
 136};
 137
 138static struct platform_driver ath79_reset_driver = {
 139        .probe  = ath79_reset_probe,
 140        .driver = {
 141                .name                   = "ath79-reset",
 142                .of_match_table         = ath79_reset_dt_ids,
 143                .suppress_bind_attrs    = true,
 144        },
 145};
 146builtin_platform_driver(ath79_reset_driver);
 147