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/platform_device.h>
7 #include <linux/reset-controller.h>
8 #include <linux/delay.h>
9 #include <linux/mfd/syscon.h>
10 #include <linux/regmap.h>
11 #include <soc/canaan/k210-sysctl.h>
12
13 #include <dt-bindings/reset/k210-rst.h>
14
15 #define K210_RST_MASK 0x27FFFFFF
16
17 struct k210_rst {
18 struct regmap *map;
19 struct reset_controller_dev rcdev;
20 };
21
22 static inline struct k210_rst *
to_k210_rst(struct reset_controller_dev * rcdev)23 to_k210_rst(struct reset_controller_dev *rcdev)
24 {
25 return container_of(rcdev, struct k210_rst, rcdev);
26 }
27
k210_rst_assert(struct reset_controller_dev * rcdev,unsigned long id)28 static inline int k210_rst_assert(struct reset_controller_dev *rcdev,
29 unsigned long id)
30 {
31 struct k210_rst *ksr = to_k210_rst(rcdev);
32
33 return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 1);
34 }
35
k210_rst_deassert(struct reset_controller_dev * rcdev,unsigned long id)36 static inline int k210_rst_deassert(struct reset_controller_dev *rcdev,
37 unsigned long id)
38 {
39 struct k210_rst *ksr = to_k210_rst(rcdev);
40
41 return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 0);
42 }
43
k210_rst_reset(struct reset_controller_dev * rcdev,unsigned long id)44 static int k210_rst_reset(struct reset_controller_dev *rcdev,
45 unsigned long id)
46 {
47 int ret;
48
49 ret = k210_rst_assert(rcdev, id);
50 if (ret == 0) {
51 udelay(10);
52 ret = k210_rst_deassert(rcdev, id);
53 }
54
55 return ret;
56 }
57
k210_rst_status(struct reset_controller_dev * rcdev,unsigned long id)58 static int k210_rst_status(struct reset_controller_dev *rcdev,
59 unsigned long id)
60 {
61 struct k210_rst *ksr = to_k210_rst(rcdev);
62 u32 reg, bit = BIT(id);
63 int ret;
64
65 ret = regmap_read(ksr->map, K210_SYSCTL_PERI_RESET, ®);
66 if (ret)
67 return ret;
68
69 return reg & bit;
70 }
71
k210_rst_xlate(struct reset_controller_dev * rcdev,const struct of_phandle_args * reset_spec)72 static int k210_rst_xlate(struct reset_controller_dev *rcdev,
73 const struct of_phandle_args *reset_spec)
74 {
75 unsigned long id = reset_spec->args[0];
76
77 if (!(BIT(id) & K210_RST_MASK))
78 return -EINVAL;
79
80 return id;
81 }
82
83 static const struct reset_control_ops k210_rst_ops = {
84 .assert = k210_rst_assert,
85 .deassert = k210_rst_deassert,
86 .reset = k210_rst_reset,
87 .status = k210_rst_status,
88 };
89
k210_rst_probe(struct platform_device * pdev)90 static int k210_rst_probe(struct platform_device *pdev)
91 {
92 struct device *dev = &pdev->dev;
93 struct device_node *parent_np;
94 struct k210_rst *ksr;
95
96 dev_info(dev, "K210 reset controller\n");
97
98 ksr = devm_kzalloc(dev, sizeof(*ksr), GFP_KERNEL);
99 if (!ksr)
100 return -ENOMEM;
101
102 parent_np = of_get_parent(dev->of_node);
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