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