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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) STMicroelectronics 2018 - All Rights Reserved
* Author: Gabriel Fernandez <gabriel.fernandez@st.com> for STMicroelectronics.
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reset-controller.h>
#define CLR_OFFSET 0x4
struct stm32_reset_data {
struct reset_controller_dev rcdev;
void __iomem *membase;
};
static inline struct stm32_reset_data *
to_stm32_reset_data(struct reset_controller_dev *rcdev)
{
return container_of(rcdev, struct stm32_reset_data, rcdev);
}
static int stm32_reset_update(struct reset_controller_dev *rcdev,
unsigned long id, bool assert)
{
struct stm32_reset_data *data = to_stm32_reset_data(rcdev);
int reg_width = sizeof(u32);
int bank = id / (reg_width * BITS_PER_BYTE);
int offset = id % (reg_width * BITS_PER_BYTE);
void __iomem *addr;
addr = data->membase + (bank * reg_width);
if (!assert)
addr += CLR_OFFSET;
writel(BIT(offset), addr);
return 0;
}
static int stm32_reset_assert(struct reset_controller_dev *rcdev,
unsigned long id)
{
return stm32_reset_update(rcdev, id, true);
}
static int stm32_reset_deassert(struct reset_controller_dev *rcdev,
unsigned long id)
{
return stm32_reset_update(rcdev, id, false);
}
static int stm32_reset_status(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct stm32_reset_data *data = to_stm32_reset_data(rcdev);
int reg_width = sizeof(u32);
int bank = id / (reg_width * BITS_PER_BYTE);
int offset = id % (reg_width * BITS_PER_BYTE);
u32 reg;
reg = readl(data->membase + (bank * reg_width));
return !!(reg & BIT(offset));
}
static const struct reset_control_ops stm32_reset_ops = {
.assert = stm32_reset_assert,
.deassert = stm32_reset_deassert,
.status = stm32_reset_status,
};
static const struct of_device_id stm32_reset_dt_ids[] = {
{ .compatible = "st,stm32mp1-rcc"},
{ /* sentinel */ },
};
static int stm32_reset_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct stm32_reset_data *data;
void __iomem *membase;
struct resource *res;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
membase = devm_ioremap_resource(dev, res);
if (IS_ERR(membase))
return PTR_ERR(membase);
data->membase = membase;
data->rcdev.owner = THIS_MODULE;
data->rcdev.nr_resets = resource_size(res) * BITS_PER_BYTE;
data->rcdev.ops = &stm32_reset_ops;
data->rcdev.of_node = dev->of_node;
return devm_reset_controller_register(dev, &data->rcdev);
}
static struct platform_driver stm32_reset_driver = {
.probe = stm32_reset_probe,
.driver = {
.name = "stm32mp1-reset",
.of_match_table = stm32_reset_dt_ids,
},
};
builtin_platform_driver(stm32_reset_driver);
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