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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * AR71xx Reset Controller Driver4 * Author: Alban Bedel5 *6 * Copyright (C) 2015 Alban Bedel <albeu@free.fr>7 */8 9#include <linux/io.h>10#include <linux/init.h>11#include <linux/mod_devicetable.h>12#include <linux/platform_device.h>13#include <linux/reset-controller.h>14#include <linux/reboot.h>15 16struct ath79_reset {17 struct reset_controller_dev rcdev;18 struct notifier_block restart_nb;19 void __iomem *base;20 spinlock_t lock;21};22 23#define FULL_CHIP_RESET 2424 25static int ath79_reset_update(struct reset_controller_dev *rcdev,26 unsigned long id, bool assert)27{28 struct ath79_reset *ath79_reset =29 container_of(rcdev, struct ath79_reset, rcdev);30 unsigned long flags;31 u32 val;32 33 spin_lock_irqsave(&ath79_reset->lock, flags);34 val = readl(ath79_reset->base);35 if (assert)36 val |= BIT(id);37 else38 val &= ~BIT(id);39 writel(val, ath79_reset->base);40 spin_unlock_irqrestore(&ath79_reset->lock, flags);41 42 return 0;43}44 45static int ath79_reset_assert(struct reset_controller_dev *rcdev,46 unsigned long id)47{48 return ath79_reset_update(rcdev, id, true);49}50 51static int ath79_reset_deassert(struct reset_controller_dev *rcdev,52 unsigned long id)53{54 return ath79_reset_update(rcdev, id, false);55}56 57static int ath79_reset_status(struct reset_controller_dev *rcdev,58 unsigned long id)59{60 struct ath79_reset *ath79_reset =61 container_of(rcdev, struct ath79_reset, rcdev);62 u32 val;63 64 val = readl(ath79_reset->base);65 66 return !!(val & BIT(id));67}68 69static const struct reset_control_ops ath79_reset_ops = {70 .assert = ath79_reset_assert,71 .deassert = ath79_reset_deassert,72 .status = ath79_reset_status,73};74 75static int ath79_reset_restart_handler(struct notifier_block *nb,76 unsigned long action, void *data)77{78 struct ath79_reset *ath79_reset =79 container_of(nb, struct ath79_reset, restart_nb);80 81 ath79_reset_assert(&ath79_reset->rcdev, FULL_CHIP_RESET);82 83 return NOTIFY_DONE;84}85 86static int ath79_reset_probe(struct platform_device *pdev)87{88 struct ath79_reset *ath79_reset;89 int err;90 91 ath79_reset = devm_kzalloc(&pdev->dev,92 sizeof(*ath79_reset), GFP_KERNEL);93 if (!ath79_reset)94 return -ENOMEM;95 96 ath79_reset->base = devm_platform_ioremap_resource(pdev, 0);97 if (IS_ERR(ath79_reset->base))98 return PTR_ERR(ath79_reset->base);99 100 spin_lock_init(&ath79_reset->lock);101 ath79_reset->rcdev.ops = &ath79_reset_ops;102 ath79_reset->rcdev.owner = THIS_MODULE;103 ath79_reset->rcdev.of_node = pdev->dev.of_node;104 ath79_reset->rcdev.of_reset_n_cells = 1;105 ath79_reset->rcdev.nr_resets = 32;106 107 err = devm_reset_controller_register(&pdev->dev, &ath79_reset->rcdev);108 if (err)109 return err;110 111 ath79_reset->restart_nb.notifier_call = ath79_reset_restart_handler;112 ath79_reset->restart_nb.priority = 128;113 114 err = register_restart_handler(&ath79_reset->restart_nb);115 if (err)116 dev_warn(&pdev->dev, "Failed to register restart handler\n");117 118 return 0;119}120 121static const struct of_device_id ath79_reset_dt_ids[] = {122 { .compatible = "qca,ar7100-reset", },123 { },124};125 126static struct platform_driver ath79_reset_driver = {127 .probe = ath79_reset_probe,128 .driver = {129 .name = "ath79-reset",130 .of_match_table = ath79_reset_dt_ids,131 .suppress_bind_attrs = true,132 },133};134builtin_platform_driver(ath79_reset_driver);135