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// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
* Amlogic Meson Reset Controller driver
*
* Copyright (c) 2016 BayLibre, SAS.
* Author: Neil Armstrong <narmstrong@baylibre.com>
*/
#include <linux/err.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/of_device.h>
#define REG_COUNT 8
#define BITS_PER_REG 32
#define LEVEL_OFFSET 0x7c
struct meson_reset {
void __iomem *reg_base;
struct reset_controller_dev rcdev;
spinlock_t lock;
};
static int meson_reset_reset(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct meson_reset *data =
container_of(rcdev, struct meson_reset, rcdev);
unsigned int bank = id / BITS_PER_REG;
unsigned int offset = id % BITS_PER_REG;
void __iomem *reg_addr = data->reg_base + (bank << 2);
writel(BIT(offset), reg_addr);
return 0;
}
static int meson_reset_level(struct reset_controller_dev *rcdev,
unsigned long id, bool assert)
{
struct meson_reset *data =
container_of(rcdev, struct meson_reset, rcdev);
unsigned int bank = id / BITS_PER_REG;
unsigned int offset = id % BITS_PER_REG;
void __iomem *reg_addr = data->reg_base + LEVEL_OFFSET + (bank << 2);
unsigned long flags;
u32 reg;
spin_lock_irqsave(&data->lock, flags);
reg = readl(reg_addr);
if (assert)
writel(reg & ~BIT(offset), reg_addr);
else
writel(reg | BIT(offset), reg_addr);
spin_unlock_irqrestore(&data->lock, flags);
return 0;
}
static int meson_reset_assert(struct reset_controller_dev *rcdev,
unsigned long id)
{
return meson_reset_level(rcdev, id, true);
}
static int meson_reset_deassert(struct reset_controller_dev *rcdev,
unsigned long id)
{
return meson_reset_level(rcdev, id, false);
}
static const struct reset_control_ops meson_reset_ops = {
.reset = meson_reset_reset,
.assert = meson_reset_assert,
.deassert = meson_reset_deassert,
};
static const struct of_device_id meson_reset_dt_ids[] = {
{ .compatible = "amlogic,meson8b-reset" },
{ .compatible = "amlogic,meson-gxbb-reset" },
{ .compatible = "amlogic,meson-axg-reset" },
{ /* sentinel */ },
};
static int meson_reset_probe(struct platform_device *pdev)
{
struct meson_reset *data;
struct resource *res;
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
data->reg_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(data->reg_base))
return PTR_ERR(data->reg_base);
platform_set_drvdata(pdev, data);
spin_lock_init(&data->lock);
data->rcdev.owner = THIS_MODULE;
data->rcdev.nr_resets = REG_COUNT * BITS_PER_REG;
data->rcdev.ops = &meson_reset_ops;
data->rcdev.of_node = pdev->dev.of_node;
return devm_reset_controller_register(&pdev->dev, &data->rcdev);
}
static struct platform_driver meson_reset_driver = {
.probe = meson_reset_probe,
.driver = {
.name = "meson_reset",
.of_match_table = meson_reset_dt_ids,
},
};
builtin_platform_driver(meson_reset_driver);
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