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135 lines
3.5 KiB
135 lines
3.5 KiB
// 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 <[email protected]> |
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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 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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