136 lines
3.5 KiB
C
136 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* BCM6345 Reset Controller Driver
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*
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* Copyright (C) 2020 Álvaro Fernández Rojas <noltari@gmail.com>
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*/
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/mod_devicetable.h>
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#include <linux/platform_device.h>
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#include <linux/reset-controller.h>
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#define BCM6345_RESET_NUM 32
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#define BCM6345_RESET_SLEEP_MIN_US 10000
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#define BCM6345_RESET_SLEEP_MAX_US 20000
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struct bcm6345_reset {
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struct reset_controller_dev rcdev;
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void __iomem *base;
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spinlock_t lock;
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};
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static inline struct bcm6345_reset *
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to_bcm6345_reset(struct reset_controller_dev *rcdev)
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{
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return container_of(rcdev, struct bcm6345_reset, rcdev);
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}
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static int bcm6345_reset_update(struct reset_controller_dev *rcdev,
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unsigned long id, bool assert)
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{
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struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);
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unsigned long flags;
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uint32_t val;
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spin_lock_irqsave(&bcm6345_reset->lock, flags);
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val = __raw_readl(bcm6345_reset->base);
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if (assert)
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val &= ~BIT(id);
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else
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val |= BIT(id);
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__raw_writel(val, bcm6345_reset->base);
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spin_unlock_irqrestore(&bcm6345_reset->lock, flags);
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return 0;
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}
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static int bcm6345_reset_assert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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return bcm6345_reset_update(rcdev, id, true);
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}
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static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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return bcm6345_reset_update(rcdev, id, false);
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}
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static int bcm6345_reset_reset(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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bcm6345_reset_update(rcdev, id, true);
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usleep_range(BCM6345_RESET_SLEEP_MIN_US,
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BCM6345_RESET_SLEEP_MAX_US);
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bcm6345_reset_update(rcdev, id, false);
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/*
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* Ensure component is taken out reset state by sleeping also after
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* deasserting the reset. Otherwise, the component may not be ready
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* for operation.
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*/
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usleep_range(BCM6345_RESET_SLEEP_MIN_US,
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BCM6345_RESET_SLEEP_MAX_US);
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return 0;
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}
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static int bcm6345_reset_status(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);
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return !(__raw_readl(bcm6345_reset->base) & BIT(id));
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}
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static const struct reset_control_ops bcm6345_reset_ops = {
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.assert = bcm6345_reset_assert,
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.deassert = bcm6345_reset_deassert,
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.reset = bcm6345_reset_reset,
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.status = bcm6345_reset_status,
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};
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static int bcm6345_reset_probe(struct platform_device *pdev)
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{
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struct bcm6345_reset *bcm6345_reset;
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bcm6345_reset = devm_kzalloc(&pdev->dev,
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sizeof(*bcm6345_reset), GFP_KERNEL);
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if (!bcm6345_reset)
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return -ENOMEM;
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platform_set_drvdata(pdev, bcm6345_reset);
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bcm6345_reset->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(bcm6345_reset->base))
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return PTR_ERR(bcm6345_reset->base);
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spin_lock_init(&bcm6345_reset->lock);
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bcm6345_reset->rcdev.ops = &bcm6345_reset_ops;
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bcm6345_reset->rcdev.owner = THIS_MODULE;
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bcm6345_reset->rcdev.of_node = pdev->dev.of_node;
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bcm6345_reset->rcdev.of_reset_n_cells = 1;
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bcm6345_reset->rcdev.nr_resets = BCM6345_RESET_NUM;
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return devm_reset_controller_register(&pdev->dev,
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&bcm6345_reset->rcdev);
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}
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static const struct of_device_id bcm6345_reset_of_match[] = {
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{ .compatible = "brcm,bcm6345-reset" },
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{ /* sentinel */ },
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};
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static struct platform_driver bcm6345_reset_driver = {
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.probe = bcm6345_reset_probe,
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.driver = {
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.name = "bcm6345-reset",
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.of_match_table = bcm6345_reset_of_match,
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.suppress_bind_attrs = true,
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},
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};
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builtin_platform_driver(bcm6345_reset_driver);
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