xref: /openbmc/linux/drivers/reset/reset-meson.c (revision 5d0e4d78)
1 /*
2  * Amlogic Meson Reset Controller driver
3  *
4  * This file is provided under a dual BSD/GPLv2 license.  When using or
5  * redistributing this file, you may do so under either license.
6  *
7  * GPL LICENSE SUMMARY
8  *
9  * Copyright (c) 2016 BayLibre, SAS.
10  * Author: Neil Armstrong <narmstrong@baylibre.com>
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of version 2 of the GNU General Public License as
14  * published by the Free Software Foundation.
15  *
16  * This program is distributed in the hope that it will be useful, but
17  * WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
19  * General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, see <http://www.gnu.org/licenses/>.
23  * The full GNU General Public License is included in this distribution
24  * in the file called COPYING.
25  *
26  * BSD LICENSE
27  *
28  * Copyright (c) 2016 BayLibre, SAS.
29  * Author: Neil Armstrong <narmstrong@baylibre.com>
30  *
31  * Redistribution and use in source and binary forms, with or without
32  * modification, are permitted provided that the following conditions
33  * are met:
34  *
35  *   * Redistributions of source code must retain the above copyright
36  *     notice, this list of conditions and the following disclaimer.
37  *   * Redistributions in binary form must reproduce the above copyright
38  *     notice, this list of conditions and the following disclaimer in
39  *     the documentation and/or other materials provided with the
40  *     distribution.
41  *   * Neither the name of Intel Corporation nor the names of its
42  *     contributors may be used to endorse or promote products derived
43  *     from this software without specific prior written permission.
44  *
45  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
46  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
47  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
48  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
49  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
50  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
51  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
52  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
53  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
54  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
55  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
56  */
57 #include <linux/err.h>
58 #include <linux/init.h>
59 #include <linux/io.h>
60 #include <linux/of.h>
61 #include <linux/platform_device.h>
62 #include <linux/reset-controller.h>
63 #include <linux/slab.h>
64 #include <linux/types.h>
65 
66 #define REG_COUNT	8
67 #define BITS_PER_REG	32
68 
69 struct meson_reset {
70 	void __iomem *reg_base;
71 	struct reset_controller_dev rcdev;
72 };
73 
74 static int meson_reset_reset(struct reset_controller_dev *rcdev,
75 			      unsigned long id)
76 {
77 	struct meson_reset *data =
78 		container_of(rcdev, struct meson_reset, rcdev);
79 	unsigned int bank = id / BITS_PER_REG;
80 	unsigned int offset = id % BITS_PER_REG;
81 	void __iomem *reg_addr = data->reg_base + (bank << 2);
82 
83 	if (bank >= REG_COUNT)
84 		return -EINVAL;
85 
86 	writel(BIT(offset), reg_addr);
87 
88 	return 0;
89 }
90 
91 static const struct reset_control_ops meson_reset_ops = {
92 	.reset		= meson_reset_reset,
93 };
94 
95 static const struct of_device_id meson_reset_dt_ids[] = {
96 	 { .compatible = "amlogic,meson8b-reset", },
97 	 { .compatible = "amlogic,meson-gxbb-reset", },
98 	 { /* sentinel */ },
99 };
100 
101 static int meson_reset_probe(struct platform_device *pdev)
102 {
103 	struct meson_reset *data;
104 	struct resource *res;
105 
106 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
107 	if (!data)
108 		return -ENOMEM;
109 
110 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
111 	data->reg_base = devm_ioremap_resource(&pdev->dev, res);
112 	if (IS_ERR(data->reg_base))
113 		return PTR_ERR(data->reg_base);
114 
115 	platform_set_drvdata(pdev, data);
116 
117 	data->rcdev.owner = THIS_MODULE;
118 	data->rcdev.nr_resets = REG_COUNT * BITS_PER_REG;
119 	data->rcdev.ops = &meson_reset_ops;
120 	data->rcdev.of_node = pdev->dev.of_node;
121 
122 	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
123 }
124 
125 static struct platform_driver meson_reset_driver = {
126 	.probe	= meson_reset_probe,
127 	.driver = {
128 		.name		= "meson_reset",
129 		.of_match_table	= meson_reset_dt_ids,
130 	},
131 };
132 builtin_platform_driver(meson_reset_driver);
133