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 
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 
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 
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 
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 
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 
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 
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