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