// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) STMicroelectronics 2018 - All Rights Reserved
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* Author: Gabriel Fernandez <gabriel.fernandez@st.com> for STMicroelectronics.
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*/
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/reset-controller.h>
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#define CLR_OFFSET 0x4
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struct stm32_reset_data {
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struct reset_controller_dev rcdev;
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void __iomem *membase;
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};
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static inline struct stm32_reset_data *
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to_stm32_reset_data(struct reset_controller_dev *rcdev)
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{
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return container_of(rcdev, struct stm32_reset_data, rcdev);
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}
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static int stm32_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 stm32_reset_data *data = to_stm32_reset_data(rcdev);
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int reg_width = sizeof(u32);
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int bank = id / (reg_width * BITS_PER_BYTE);
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int offset = id % (reg_width * BITS_PER_BYTE);
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void __iomem *addr;
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addr = data->membase + (bank * reg_width);
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if (!assert)
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addr += CLR_OFFSET;
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writel(BIT(offset), addr);
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return 0;
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}
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static int stm32_reset_assert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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return stm32_reset_update(rcdev, id, true);
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}
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static int stm32_reset_deassert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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return stm32_reset_update(rcdev, id, false);
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}
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static int stm32_reset_status(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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struct stm32_reset_data *data = to_stm32_reset_data(rcdev);
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int reg_width = sizeof(u32);
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int bank = id / (reg_width * BITS_PER_BYTE);
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int offset = id % (reg_width * BITS_PER_BYTE);
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u32 reg;
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reg = readl(data->membase + (bank * reg_width));
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return !!(reg & BIT(offset));
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}
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static const struct reset_control_ops stm32_reset_ops = {
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.assert = stm32_reset_assert,
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.deassert = stm32_reset_deassert,
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.status = stm32_reset_status,
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};
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static const struct of_device_id stm32_reset_dt_ids[] = {
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{ .compatible = "st,stm32mp1-rcc"},
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{ /* sentinel */ },
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};
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static int stm32_reset_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct stm32_reset_data *data;
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void __iomem *membase;
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struct resource *res;
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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membase = devm_ioremap_resource(dev, res);
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if (IS_ERR(membase))
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return PTR_ERR(membase);
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data->membase = membase;
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data->rcdev.owner = THIS_MODULE;
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data->rcdev.nr_resets = resource_size(res) * BITS_PER_BYTE;
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data->rcdev.ops = &stm32_reset_ops;
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data->rcdev.of_node = dev->of_node;
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return devm_reset_controller_register(dev, &data->rcdev);
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}
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static struct platform_driver stm32_reset_driver = {
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.probe = stm32_reset_probe,
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.driver = {
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.name = "stm32mp1-reset",
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.of_match_table = stm32_reset_dt_ids,
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},
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};
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builtin_platform_driver(stm32_reset_driver);
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