1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2016-2017 Linaro Ltd.
4 * Copyright (c) 2016-2017 HiSilicon Technologies Co., Ltd.
5 */
6 #include <linux/kernel.h>
7 #include <linux/mfd/syscon.h>
8 #include <linux/module.h>
9 #include <linux/of.h>
10 #include <linux/platform_device.h>
11 #include <linux/regmap.h>
12 #include <linux/reset-controller.h>
13
14 struct hi3660_reset_controller {
15 struct reset_controller_dev rst;
16 struct regmap *map;
17 };
18
19 #define to_hi3660_reset_controller(_rst) \
20 container_of(_rst, struct hi3660_reset_controller, rst)
21
hi3660_reset_program_hw(struct reset_controller_dev * rcdev,unsigned long idx,bool assert)22 static int hi3660_reset_program_hw(struct reset_controller_dev *rcdev,
23 unsigned long idx, bool assert)
24 {
25 struct hi3660_reset_controller *rc = to_hi3660_reset_controller(rcdev);
26 unsigned int offset = idx >> 8;
27 unsigned int mask = BIT(idx & 0x1f);
28
29 if (assert)
30 return regmap_write(rc->map, offset, mask);
31 else
32 return regmap_write(rc->map, offset + 4, mask);
33 }
34
hi3660_reset_assert(struct reset_controller_dev * rcdev,unsigned long idx)35 static int hi3660_reset_assert(struct reset_controller_dev *rcdev,
36 unsigned long idx)
37 {
38 return hi3660_reset_program_hw(rcdev, idx, true);
39 }
40
hi3660_reset_deassert(struct reset_controller_dev * rcdev,unsigned long idx)41 static int hi3660_reset_deassert(struct reset_controller_dev *rcdev,
42 unsigned long idx)
43 {
44 return hi3660_reset_program_hw(rcdev, idx, false);
45 }
46
hi3660_reset_dev(struct reset_controller_dev * rcdev,unsigned long idx)47 static int hi3660_reset_dev(struct reset_controller_dev *rcdev,
48 unsigned long idx)
49 {
50 int err;
51
52 err = hi3660_reset_assert(rcdev, idx);
53 if (err)
54 return err;
55
56 return hi3660_reset_deassert(rcdev, idx);
57 }
58
59 static const struct reset_control_ops hi3660_reset_ops = {
60 .reset = hi3660_reset_dev,
61 .assert = hi3660_reset_assert,
62 .deassert = hi3660_reset_deassert,
63 };
64
hi3660_reset_xlate(struct reset_controller_dev * rcdev,const struct of_phandle_args * reset_spec)65 static int hi3660_reset_xlate(struct reset_controller_dev *rcdev,
66 const struct of_phandle_args *reset_spec)
67 {
68 unsigned int offset, bit;
69
70 offset = reset_spec->args[0];
71 bit = reset_spec->args[1];
72
73 return (offset << 8) | bit;
74 }
75
hi3660_reset_probe(struct platform_device * pdev)76 static int hi3660_reset_probe(struct platform_device *pdev)
77 {
78 struct hi3660_reset_controller *rc;
79 struct device_node *np = pdev->dev.of_node;
80 struct device *dev = &pdev->dev;
81
82 rc = devm_kzalloc(dev, sizeof(*rc), GFP_KERNEL);
83 if (!rc)
84 return -ENOMEM;
85
86 rc->map = syscon_regmap_lookup_by_phandle(np, "hisilicon,rst-syscon");
87 if (rc->map == ERR_PTR(-ENODEV)) {
88 /* fall back to the deprecated compatible */
89 rc->map = syscon_regmap_lookup_by_phandle(np,
90 "hisi,rst-syscon");
91 }
92 if (IS_ERR(rc->map)) {
93 return dev_err_probe(dev, PTR_ERR(rc->map),
94 "failed to get hisilicon,rst-syscon\n");
95 }
96
97 rc->rst.ops = &hi3660_reset_ops,
98 rc->rst.of_node = np;
99 rc->rst.of_reset_n_cells = 2;
100 rc->rst.of_xlate = hi3660_reset_xlate;
101
102 return reset_controller_register(&rc->rst);
103 }
104
105 static const struct of_device_id hi3660_reset_match[] = {
106 { .compatible = "hisilicon,hi3660-reset", },
107 {},
108 };
109 MODULE_DEVICE_TABLE(of, hi3660_reset_match);
110
111 static struct platform_driver hi3660_reset_driver = {
112 .probe = hi3660_reset_probe,
113 .driver = {
114 .name = "hi3660-reset",
115 .of_match_table = hi3660_reset_match,
116 },
117 };
118
hi3660_reset_init(void)119 static int __init hi3660_reset_init(void)
120 {
121 return platform_driver_register(&hi3660_reset_driver);
122 }
123 arch_initcall(hi3660_reset_init);
124
125 MODULE_LICENSE("GPL");
126 MODULE_ALIAS("platform:hi3660-reset");
127 MODULE_DESCRIPTION("HiSilicon Hi3660 Reset Driver");
128