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gerrit-public.fairphone.software / kernel / msm-4.19 / 0563df2ce72b5d21217223e73f56ecfcacffb639 / . / drivers / reset / reset-zynq.c
blob: 89318a5d5bd78590d7319c05628af23e98a0e878 [file] [log] [blame]
Moritz Fischerfedf42b2015-07-30 18:13:56 -0700[diff] [blame]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
26struct 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
35static 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
52static 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
69static 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), &reg);
83 if (ret)
84 return ret;
85
86 return !!(reg & BIT(offset));
87}
88
89static struct reset_control_ops zynq_reset_ops = {
90 .assert = zynq_reset_assert,
91 .deassert = zynq_reset_deassert,
92 .status = zynq_reset_status,
93};
94
95static 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
129static 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
138static const struct of_device_id zynq_reset_dt_ids[] = {
139 { .compatible = "xlnx,zynq-reset", },
140 { /* sentinel */ },
141};
142
143static 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};
151module_platform_driver(zynq_reset_driver);
152
153MODULE_LICENSE("GPL v2");
154MODULE_AUTHOR("Moritz Fischer <moritz.fischer@ettus.com>");
155MODULE_DESCRIPTION("Zynq Reset Controller Driver");