/* * AR71xx Reset Controller Driver * Author: Alban Bedel * * Copyright (C) 2015 Alban Bedel <albeu@free.fr> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <linux/io.h> #include <linux/init.h> #include <linux/platform_device.h> #include <linux/reset-controller.h> #include <linux/reboot.h> struct ath79_reset { struct reset_controller_dev rcdev; struct notifier_block restart_nb; void __iomem *base; spinlock_t lock; }; #define FULL_CHIP_RESET 24 static int ath79_reset_update(struct reset_controller_dev *rcdev, unsigned long id, bool assert) { struct ath79_reset *ath79_reset = container_of(rcdev, struct ath79_reset, rcdev); unsigned long flags; u32 val; spin_lock_irqsave(&ath79_reset->lock, flags); val = readl(ath79_reset->base); if (assert) val |= BIT(id); else val &= ~BIT(id); writel(val, ath79_reset->base); spin_unlock_irqrestore(&ath79_reset->lock, flags); return 0; } static int ath79_reset_assert(struct reset_controller_dev *rcdev, unsigned long id) { return ath79_reset_update(rcdev, id, true); } static int ath79_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id) { return ath79_reset_update(rcdev, id, false); } static int ath79_reset_status(struct reset_controller_dev *rcdev, unsigned long id) { struct ath79_reset *ath79_reset = container_of(rcdev, struct ath79_reset, rcdev); u32 val; val = readl(ath79_reset->base); return !!(val & BIT(id)); } static const struct reset_control_ops ath79_reset_ops = { .assert = ath79_reset_assert, .deassert = ath79_reset_deassert, .status = ath79_reset_status, }; static int ath79_reset_restart_handler(struct notifier_block *nb, unsigned long action, void *data) { struct ath79_reset *ath79_reset = container_of(nb, struct ath79_reset, restart_nb); ath79_reset_assert(&ath79_reset->rcdev, FULL_CHIP_RESET); return NOTIFY_DONE; } static int ath79_reset_probe(struct platform_device *pdev) { struct ath79_reset *ath79_reset; struct resource *res; int err; ath79_reset = devm_kzalloc(&pdev->dev, sizeof(*ath79_reset), GFP_KERNEL); if (!ath79_reset) return -ENOMEM; platform_set_drvdata(pdev, ath79_reset); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); ath79_reset->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(ath79_reset->base)) return PTR_ERR(ath79_reset->base); spin_lock_init(&ath79_reset->lock); ath79_reset->rcdev.ops = &ath79_reset_ops; ath79_reset->rcdev.owner = THIS_MODULE; ath79_reset->rcdev.of_node = pdev->dev.of_node; ath79_reset->rcdev.of_reset_n_cells = 1; ath79_reset->rcdev.nr_resets = 32; err = devm_reset_controller_register(&pdev->dev, &ath79_reset->rcdev); if (err) return err; ath79_reset->restart_nb.notifier_call = ath79_reset_restart_handler; ath79_reset->restart_nb.priority = 128; err = register_restart_handler(&ath79_reset->restart_nb); if (err) dev_warn(&pdev->dev, "Failed to register restart handler\n"); return 0; } static const struct of_device_id ath79_reset_dt_ids[] = { { .compatible = "qca,ar7100-reset", }, { }, }; static struct platform_driver ath79_reset_driver = { .probe = ath79_reset_probe, .driver = { .name = "ath79-reset", .of_match_table = ath79_reset_dt_ids, .suppress_bind_attrs = true, }, }; builtin_platform_driver(ath79_reset_driver);