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
20 struct meson_reset_param {
21 int reg_count;
22 int level_offset;
23 };
24
25 struct 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
meson_reset_reset(struct reset_controller_dev * rcdev,unsigned long id)32 static 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
meson_reset_level(struct reset_controller_dev * rcdev,unsigned long id,bool assert)46 static 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
meson_reset_assert(struct reset_controller_dev * rcdev,unsigned long id)72 static int meson_reset_assert(struct reset_controller_dev *rcdev,
73 unsigned long id)
74 {
75 return meson_reset_level(rcdev, id, true);
76 }
77
meson_reset_deassert(struct reset_controller_dev * rcdev,unsigned long id)78 static int meson_reset_deassert(struct reset_controller_dev *rcdev,
79 unsigned long id)
80 {
81 return meson_reset_level(rcdev, id, false);
82 }
83
84 static 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
90 static const struct meson_reset_param meson8b_param = {
91 .reg_count = 8,
92 .level_offset = 0x7c,
93 };
94
95 static const struct meson_reset_param meson_a1_param = {
96 .reg_count = 3,
97 .level_offset = 0x40,
98 };
99
100 static const struct meson_reset_param meson_s4_param = {
101 .reg_count = 6,
102 .level_offset = 0x40,
103 };
104
105 static const struct meson_reset_param t7_param = {
106 .reg_count = 7,
107 .level_offset = 0x40,
108 };
109
110 static const struct of_device_id meson_reset_dt_ids[] = {
111 { .compatible = "amlogic,meson8b-reset", .data = &meson8b_param},
112 { .compatible = "amlogic,meson-gxbb-reset", .data = &meson8b_param},
113 { .compatible = "amlogic,meson-axg-reset", .data = &meson8b_param},
114 { .compatible = "amlogic,meson-a1-reset", .data = &meson_a1_param},
115 { .compatible = "amlogic,meson-s4-reset", .data = &meson_s4_param},
116 { .compatible = "amlogic,c3-reset", .data = &meson_s4_param},
117 { .compatible = "amlogic,t7-reset", .data = &t7_param},
118 { /* sentinel */ },
119 };
120 MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
121
meson_reset_probe(struct platform_device * pdev)122 static int meson_reset_probe(struct platform_device *pdev)
123 {
124 struct meson_reset *data;
125
126 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
127 if (!data)
128 return -ENOMEM;
129
130 data->reg_base = devm_platform_ioremap_resource(pdev, 0);
131 if (IS_ERR(data->reg_base))
132 return PTR_ERR(data->reg_base);
133
134 data->param = of_device_get_match_data(&pdev->dev);
135 if (!data->param)
136 return -ENODEV;
137
138 spin_lock_init(&data->lock);
139
140 data->rcdev.owner = THIS_MODULE;
141 data->rcdev.nr_resets = data->param->reg_count * BITS_PER_REG;
142 data->rcdev.ops = &meson_reset_ops;
143 data->rcdev.of_node = pdev->dev.of_node;
144
145 return devm_reset_controller_register(&pdev->dev, &data->rcdev);
146 }
147
148 static struct platform_driver meson_reset_driver = {
149 .probe = meson_reset_probe,
150 .driver = {
151 .name = "meson_reset",
152 .of_match_table = meson_reset_dt_ids,
153 },
154 };
155 module_platform_driver(meson_reset_driver);
156
157 MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver");
158 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
159 MODULE_LICENSE("Dual BSD/GPL");
160