1// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2/*
3 * Amlogic Meson Reset Controller driver
4 *
5 * Copyright (c) 2016 BayLibre, SAS.
6 * Author: Neil Armstrong <narmstrong@baylibre.com>
7 */
8#include <linux/err.h>
9#include <linux/init.h>
10#include <linux/io.h>
11#include <linux/of.h>
12#include <linux/module.h>
13#include <linux/platform_device.h>
14#include <linux/reset-controller.h>
15#include <linux/slab.h>
16#include <linux/types.h>
17
18#define BITS_PER_REG	32
19
20struct meson_reset_param {
21	int reg_count;
22	int level_offset;
23};
24
25struct meson_reset {
26	void __iomem *reg_base;
27	const struct meson_reset_param *param;
28	struct reset_controller_dev rcdev;
29	spinlock_t lock;
30};
31
32static int meson_reset_reset(struct reset_controller_dev *rcdev,
33			      unsigned long id)
34{
35	struct meson_reset *data =
36		container_of(rcdev, struct meson_reset, rcdev);
37	unsigned int bank = id / BITS_PER_REG;
38	unsigned int offset = id % BITS_PER_REG;
39	void __iomem *reg_addr = data->reg_base + (bank << 2);
40
41	writel(BIT(offset), reg_addr);
42
43	return 0;
44}
45
46static int meson_reset_level(struct reset_controller_dev *rcdev,
47			    unsigned long id, bool assert)
48{
49	struct meson_reset *data =
50		container_of(rcdev, struct meson_reset, rcdev);
51	unsigned int bank = id / BITS_PER_REG;
52	unsigned int offset = id % BITS_PER_REG;
53	void __iomem *reg_addr;
54	unsigned long flags;
55	u32 reg;
56
57	reg_addr = data->reg_base + data->param->level_offset + (bank << 2);
58
59	spin_lock_irqsave(&data->lock, flags);
60
61	reg = readl(reg_addr);
62	if (assert)
63		writel(reg & ~BIT(offset), reg_addr);
64	else
65		writel(reg | BIT(offset), reg_addr);
66
67	spin_unlock_irqrestore(&data->lock, flags);
68
69	return 0;
70}
71
72static int meson_reset_assert(struct reset_controller_dev *rcdev,
73			      unsigned long id)
74{
75	return meson_reset_level(rcdev, id, true);
76}
77
78static int meson_reset_deassert(struct reset_controller_dev *rcdev,
79				unsigned long id)
80{
81	return meson_reset_level(rcdev, id, false);
82}
83
84static const struct reset_control_ops meson_reset_ops = {
85	.reset		= meson_reset_reset,
86	.assert		= meson_reset_assert,
87	.deassert	= meson_reset_deassert,
88};
89
90static const struct meson_reset_param meson8b_param = {
91	.reg_count	= 8,
92	.level_offset	= 0x7c,
93};
94
95static const struct meson_reset_param meson_a1_param = {
96	.reg_count	= 3,
97	.level_offset	= 0x40,
98};
99
100static const struct meson_reset_param meson_s4_param = {
101	.reg_count	= 6,
102	.level_offset	= 0x40,
103};
104
105static const struct of_device_id meson_reset_dt_ids[] = {
106	 { .compatible = "amlogic,meson8b-reset",    .data = &meson8b_param},
107	 { .compatible = "amlogic,meson-gxbb-reset", .data = &meson8b_param},
108	 { .compatible = "amlogic,meson-axg-reset",  .data = &meson8b_param},
109	 { .compatible = "amlogic,meson-a1-reset",   .data = &meson_a1_param},
110	 { .compatible = "amlogic,meson-s4-reset",   .data = &meson_s4_param},
111	 { .compatible = "amlogic,c3-reset",   .data = &meson_s4_param},
112	 { /* sentinel */ },
113};
114MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
115
116static int meson_reset_probe(struct platform_device *pdev)
117{
118	struct meson_reset *data;
119
120	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
121	if (!data)
122		return -ENOMEM;
123
124	data->reg_base = devm_platform_ioremap_resource(pdev, 0);
125	if (IS_ERR(data->reg_base))
126		return PTR_ERR(data->reg_base);
127
128	data->param = of_device_get_match_data(&pdev->dev);
129	if (!data->param)
130		return -ENODEV;
131
132	spin_lock_init(&data->lock);
133
134	data->rcdev.owner = THIS_MODULE;
135	data->rcdev.nr_resets = data->param->reg_count * BITS_PER_REG;
136	data->rcdev.ops = &meson_reset_ops;
137	data->rcdev.of_node = pdev->dev.of_node;
138
139	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
140}
141
142static struct platform_driver meson_reset_driver = {
143	.probe	= meson_reset_probe,
144	.driver = {
145		.name		= "meson_reset",
146		.of_match_table	= meson_reset_dt_ids,
147	},
148};
149module_platform_driver(meson_reset_driver);
150
151MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver");
152MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
153MODULE_LICENSE("Dual BSD/GPL");
154