1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2020 Western Digital Corporation or its affiliates.
4 */
5 #include <linux/of.h>
6 #include <linux/of_device.h>
7 #include <linux/platform_device.h>
8 #include <linux/reset-controller.h>
9 #include <linux/delay.h>
10 #include <linux/mfd/syscon.h>
11 #include <linux/regmap.h>
12 #include <soc/canaan/k210-sysctl.h>
13
14 #include <dt-bindings/reset/k210-rst.h>
15
16 #define K210_RST_MASK 0x27FFFFFF
17
18 struct k210_rst {
19 struct regmap *map;
20 struct reset_controller_dev rcdev;
21 };
22
23 static inline struct k210_rst *
to_k210_rst(struct reset_controller_dev * rcdev)24 to_k210_rst(struct reset_controller_dev *rcdev)
25 {
26 return container_of(rcdev, struct k210_rst, rcdev);
27 }
28
k210_rst_assert(struct reset_controller_dev * rcdev,unsigned long id)29 static inline int k210_rst_assert(struct reset_controller_dev *rcdev,
30 unsigned long id)
31 {
32 struct k210_rst *ksr = to_k210_rst(rcdev);
33
34 return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 1);
35 }
36
k210_rst_deassert(struct reset_controller_dev * rcdev,unsigned long id)37 static inline int k210_rst_deassert(struct reset_controller_dev *rcdev,
38 unsigned long id)
39 {
40 struct k210_rst *ksr = to_k210_rst(rcdev);
41
42 return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 0);
43 }
44
k210_rst_reset(struct reset_controller_dev * rcdev,unsigned long id)45 static int k210_rst_reset(struct reset_controller_dev *rcdev,
46 unsigned long id)
47 {
48 int ret;
49
50 ret = k210_rst_assert(rcdev, id);
51 if (ret == 0) {
52 udelay(10);
53 ret = k210_rst_deassert(rcdev, id);
54 }
55
56 return ret;
57 }
58
k210_rst_status(struct reset_controller_dev * rcdev,unsigned long id)59 static int k210_rst_status(struct reset_controller_dev *rcdev,
60 unsigned long id)
61 {
62 struct k210_rst *ksr = to_k210_rst(rcdev);
63 u32 reg, bit = BIT(id);
64 int ret;
65
66 ret = regmap_read(ksr->map, K210_SYSCTL_PERI_RESET, ®);
67 if (ret)
68 return ret;
69
70 return reg & bit;
71 }
72
k210_rst_xlate(struct reset_controller_dev * rcdev,const struct of_phandle_args * reset_spec)73 static int k210_rst_xlate(struct reset_controller_dev *rcdev,
74 const struct of_phandle_args *reset_spec)
75 {
76 unsigned long id = reset_spec->args[0];
77
78 if (!(BIT(id) & K210_RST_MASK))
79 return -EINVAL;
80
81 return id;
82 }
83
84 static const struct reset_control_ops k210_rst_ops = {
85 .assert = k210_rst_assert,
86 .deassert = k210_rst_deassert,
87 .reset = k210_rst_reset,
88 .status = k210_rst_status,
89 };
90
k210_rst_probe(struct platform_device * pdev)91 static int k210_rst_probe(struct platform_device *pdev)
92 {
93 struct device *dev = &pdev->dev;
94 struct device_node *parent_np = of_get_parent(dev->of_node);
95 struct k210_rst *ksr;
96
97 dev_info(dev, "K210 reset controller\n");
98
99 ksr = devm_kzalloc(dev, sizeof(*ksr), GFP_KERNEL);
100 if (!ksr)
101 return -ENOMEM;
102
103 ksr->map = syscon_node_to_regmap(parent_np);
104 of_node_put(parent_np);
105 if (IS_ERR(ksr->map))
106 return PTR_ERR(ksr->map);
107
108 ksr->rcdev.owner = THIS_MODULE;
109 ksr->rcdev.dev = dev;
110 ksr->rcdev.of_node = dev->of_node;
111 ksr->rcdev.ops = &k210_rst_ops;
112 ksr->rcdev.nr_resets = fls(K210_RST_MASK);
113 ksr->rcdev.of_reset_n_cells = 1;
114 ksr->rcdev.of_xlate = k210_rst_xlate;
115
116 return devm_reset_controller_register(dev, &ksr->rcdev);
117 }
118
119 static const struct of_device_id k210_rst_dt_ids[] = {
120 { .compatible = "canaan,k210-rst" },
121 { /* sentinel */ },
122 };
123
124 static struct platform_driver k210_rst_driver = {
125 .probe = k210_rst_probe,
126 .driver = {
127 .name = "k210-rst",
128 .of_match_table = k210_rst_dt_ids,
129 },
130 };
131 builtin_platform_driver(k210_rst_driver);
132
