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1 | /* |
2 | * Copyright (c) 2015, National Instruments Corp. | |
3 | * | |
4 | * Xilinx Zynq Reset controller driver | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; version 2 of the License. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | */ | |
15 | ||
16 | #include <linux/err.h> | |
17 | #include <linux/io.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/mfd/syscon.h> | |
20 | #include <linux/of.h> | |
21 | #include <linux/platform_device.h> | |
22 | #include <linux/reset-controller.h> | |
23 | #include <linux/regmap.h> | |
24 | #include <linux/types.h> | |
25 | ||
26 | struct zynq_reset_data { | |
27 | struct regmap *slcr; | |
28 | struct reset_controller_dev rcdev; | |
29 | u32 offset; | |
30 | }; | |
31 | ||
32 | #define to_zynq_reset_data(p) \ | |
33 | container_of((p), struct zynq_reset_data, rcdev) | |
34 | ||
35 | static int zynq_reset_assert(struct reset_controller_dev *rcdev, | |
36 | unsigned long id) | |
37 | { | |
38 | struct zynq_reset_data *priv = to_zynq_reset_data(rcdev); | |
39 | ||
40 | int bank = id / BITS_PER_LONG; | |
41 | int offset = id % BITS_PER_LONG; | |
42 | ||
43 | pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__, | |
44 | bank, offset); | |
45 | ||
46 | return regmap_update_bits(priv->slcr, | |
47 | priv->offset + (bank * 4), | |
48 | BIT(offset), | |
49 | BIT(offset)); | |
50 | } | |
51 | ||
52 | static int zynq_reset_deassert(struct reset_controller_dev *rcdev, | |
53 | unsigned long id) | |
54 | { | |
55 | struct zynq_reset_data *priv = to_zynq_reset_data(rcdev); | |
56 | ||
57 | int bank = id / BITS_PER_LONG; | |
58 | int offset = id % BITS_PER_LONG; | |
59 | ||
60 | pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__, | |
61 | bank, offset); | |
62 | ||
63 | return regmap_update_bits(priv->slcr, | |
64 | priv->offset + (bank * 4), | |
65 | BIT(offset), | |
66 | ~BIT(offset)); | |
67 | } | |
68 | ||
69 | static int zynq_reset_status(struct reset_controller_dev *rcdev, | |
70 | unsigned long id) | |
71 | { | |
72 | struct zynq_reset_data *priv = to_zynq_reset_data(rcdev); | |
73 | ||
74 | int bank = id / BITS_PER_LONG; | |
75 | int offset = id % BITS_PER_LONG; | |
76 | int ret; | |
77 | u32 reg; | |
78 | ||
79 | pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__, | |
80 | bank, offset); | |
81 | ||
82 | ret = regmap_read(priv->slcr, priv->offset + (bank * 4), ®); | |
83 | if (ret) | |
84 | return ret; | |
85 | ||
86 | return !!(reg & BIT(offset)); | |
87 | } | |
88 | ||
89 | static struct reset_control_ops zynq_reset_ops = { | |
90 | .assert = zynq_reset_assert, | |
91 | .deassert = zynq_reset_deassert, | |
92 | .status = zynq_reset_status, | |
93 | }; | |
94 | ||
95 | static int zynq_reset_probe(struct platform_device *pdev) | |
96 | { | |
97 | struct resource *res; | |
98 | struct zynq_reset_data *priv; | |
99 | ||
100 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); | |
101 | if (!priv) | |
102 | return -ENOMEM; | |
103 | platform_set_drvdata(pdev, priv); | |
104 | ||
105 | priv->slcr = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, | |
106 | "syscon"); | |
107 | if (IS_ERR(priv->slcr)) { | |
108 | dev_err(&pdev->dev, "unable to get zynq-slcr regmap"); | |
109 | return PTR_ERR(priv->slcr); | |
110 | } | |
111 | ||
112 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
113 | if (!res) { | |
114 | dev_err(&pdev->dev, "missing IO resource\n"); | |
115 | return -ENODEV; | |
116 | } | |
117 | ||
118 | priv->offset = res->start; | |
119 | ||
120 | priv->rcdev.owner = THIS_MODULE; | |
121 | priv->rcdev.nr_resets = resource_size(res) / 4 * BITS_PER_LONG; | |
122 | priv->rcdev.ops = &zynq_reset_ops; | |
123 | priv->rcdev.of_node = pdev->dev.of_node; | |
124 | reset_controller_register(&priv->rcdev); | |
125 | ||
126 | return 0; | |
127 | } | |
128 | ||
129 | static int zynq_reset_remove(struct platform_device *pdev) | |
130 | { | |
131 | struct zynq_reset_data *priv = platform_get_drvdata(pdev); | |
132 | ||
133 | reset_controller_unregister(&priv->rcdev); | |
134 | ||
135 | return 0; | |
136 | } | |
137 | ||
138 | static const struct of_device_id zynq_reset_dt_ids[] = { | |
139 | { .compatible = "xlnx,zynq-reset", }, | |
140 | { /* sentinel */ }, | |
141 | }; | |
142 | ||
143 | static struct platform_driver zynq_reset_driver = { | |
144 | .probe = zynq_reset_probe, | |
145 | .remove = zynq_reset_remove, | |
146 | .driver = { | |
147 | .name = KBUILD_MODNAME, | |
148 | .of_match_table = zynq_reset_dt_ids, | |
149 | }, | |
150 | }; | |
151 | module_platform_driver(zynq_reset_driver); | |
152 | ||
153 | MODULE_LICENSE("GPL v2"); | |
154 | MODULE_AUTHOR("Moritz Fischer <moritz.fischer@ettus.com>"); | |
155 | MODULE_DESCRIPTION("Zynq Reset Controller Driver"); |