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