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![Philipp Zabel](/assets/img/avatar_default.png)
The reset-simple driver can be used without changes. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Reviewed-by: Alexandru Gagniuc <alex.g@adaptrum.com>
186 lines
5.1 KiB
C
186 lines
5.1 KiB
C
/*
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* Simple Reset Controller Driver
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*
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* Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
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*
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* Based on Allwinner SoCs Reset Controller driver
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*
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* Copyright 2013 Maxime Ripard
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*
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* Maxime Ripard <maxime.ripard@free-electrons.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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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/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/reset-controller.h>
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#include <linux/spinlock.h>
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#include "reset-simple.h"
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static inline struct reset_simple_data *
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to_reset_simple_data(struct reset_controller_dev *rcdev)
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{
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return container_of(rcdev, struct reset_simple_data, rcdev);
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}
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static int reset_simple_update(struct reset_controller_dev *rcdev,
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unsigned long id, bool assert)
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{
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struct reset_simple_data *data = to_reset_simple_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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unsigned long flags;
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u32 reg;
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spin_lock_irqsave(&data->lock, flags);
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reg = readl(data->membase + (bank * reg_width));
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if (assert ^ data->active_low)
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reg |= BIT(offset);
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else
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reg &= ~BIT(offset);
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writel(reg, data->membase + (bank * reg_width));
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spin_unlock_irqrestore(&data->lock, flags);
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return 0;
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}
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static int reset_simple_assert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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return reset_simple_update(rcdev, id, true);
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}
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static int reset_simple_deassert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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return reset_simple_update(rcdev, id, false);
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}
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static int reset_simple_status(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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struct reset_simple_data *data = to_reset_simple_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)) ^ !data->status_active_low;
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}
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const struct reset_control_ops reset_simple_ops = {
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.assert = reset_simple_assert,
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.deassert = reset_simple_deassert,
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.status = reset_simple_status,
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};
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/**
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* struct reset_simple_devdata - simple reset controller properties
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* @reg_offset: offset between base address and first reset register.
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* @nr_resets: number of resets. If not set, default to resource size in bits.
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* @active_low: if true, bits are cleared to assert the reset. Otherwise, bits
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* are set to assert the reset.
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* @status_active_low: if true, bits read back as cleared while the reset is
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* asserted. Otherwise, bits read back as set while the
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* reset is asserted.
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*/
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struct reset_simple_devdata {
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u32 reg_offset;
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u32 nr_resets;
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bool active_low;
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bool status_active_low;
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};
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#define SOCFPGA_NR_BANKS 8
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static const struct reset_simple_devdata reset_simple_socfpga = {
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.reg_offset = 0x10,
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.nr_resets = SOCFPGA_NR_BANKS * 32,
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.status_active_low = true,
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};
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static const struct reset_simple_devdata reset_simple_active_low = {
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.active_low = true,
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.status_active_low = true,
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};
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static const struct of_device_id reset_simple_dt_ids[] = {
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{ .compatible = "altr,rst-mgr", .data = &reset_simple_socfpga },
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{ .compatible = "st,stm32-rcc", },
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{ .compatible = "allwinner,sun6i-a31-clock-reset",
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.data = &reset_simple_active_low },
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{ .compatible = "zte,zx296718-reset",
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.data = &reset_simple_active_low },
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{ /* sentinel */ },
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};
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static int reset_simple_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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const struct reset_simple_devdata *devdata;
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struct reset_simple_data *data;
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void __iomem *membase;
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struct resource *res;
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u32 reg_offset = 0;
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devdata = of_device_get_match_data(dev);
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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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spin_lock_init(&data->lock);
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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 = &reset_simple_ops;
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data->rcdev.of_node = dev->of_node;
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if (devdata) {
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reg_offset = devdata->reg_offset;
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if (devdata->nr_resets)
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data->rcdev.nr_resets = devdata->nr_resets;
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data->active_low = devdata->active_low;
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data->status_active_low = devdata->status_active_low;
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}
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if (of_device_is_compatible(dev->of_node, "altr,rst-mgr") &&
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of_property_read_u32(dev->of_node, "altr,modrst-offset",
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®_offset)) {
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dev_warn(dev,
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"missing altr,modrst-offset property, assuming 0x%x!\n",
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reg_offset);
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}
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data->membase += reg_offset;
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return devm_reset_controller_register(dev, &data->rcdev);
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}
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static struct platform_driver reset_simple_driver = {
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.probe = reset_simple_probe,
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.driver = {
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.name = "simple-reset",
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.of_match_table = reset_simple_dt_ids,
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},
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};
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builtin_platform_driver(reset_simple_driver);
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