1/*
2 * Copyright (C) 2014 Marvell Technology Group Ltd.
3 *
4 * Marvell Berlin reset driver
5 *
6 * Antoine Tenart <antoine.tenart@free-electrons.com>
7 * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
8 *
9 * This file is licensed under the terms of the GNU General Public
10 * License version 2. This program is licensed "as is" without any
11 * warranty of any kind, whether express or implied.
12 */
13
14#include <linux/delay.h>
15#include <linux/io.h>
16#include <linux/mfd/syscon.h>
17#include <linux/module.h>
18#include <linux/of.h>
19#include <linux/of_address.h>
20#include <linux/platform_device.h>
21#include <linux/regmap.h>
22#include <linux/reset-controller.h>
23#include <linux/slab.h>
24#include <linux/types.h>
25
26#define BERLIN_MAX_RESETS	32
27
28#define to_berlin_reset_priv(p)		\
29	container_of((p), struct berlin_reset_priv, rcdev)
30
31struct berlin_reset_priv {
32	struct regmap			*regmap;
33	struct reset_controller_dev	rcdev;
34};
35
36static int berlin_reset_reset(struct reset_controller_dev *rcdev,
37			      unsigned long id)
38{
39	struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev);
40	int offset = id >> 8;
41	int mask = BIT(id & 0x1f);
42
43	regmap_write(priv->regmap, offset, mask);
44
45	/* let the reset be effective */
46	udelay(10);
47
48	return 0;
49}
50
51static const struct reset_control_ops berlin_reset_ops = {
52	.reset	= berlin_reset_reset,
53};
54
55static int berlin_reset_xlate(struct reset_controller_dev *rcdev,
56			      const struct of_phandle_args *reset_spec)
57{
58	unsigned int offset, bit;
59
60	offset = reset_spec->args[0];
61	bit = reset_spec->args[1];
62
63	if (bit >= BERLIN_MAX_RESETS)
64		return -EINVAL;
65
66	return (offset << 8) | bit;
67}
68
69static int berlin2_reset_probe(struct platform_device *pdev)
70{
71	struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
72	struct berlin_reset_priv *priv;
73
74	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
75	if (!priv)
76		return -ENOMEM;
77
78	priv->regmap = syscon_node_to_regmap(parent_np);
79	of_node_put(parent_np);
80	if (IS_ERR(priv->regmap))
81		return PTR_ERR(priv->regmap);
82
83	priv->rcdev.owner = THIS_MODULE;
84	priv->rcdev.ops = &berlin_reset_ops;
85	priv->rcdev.of_node = pdev->dev.of_node;
86	priv->rcdev.of_reset_n_cells = 2;
87	priv->rcdev.of_xlate = berlin_reset_xlate;
88
89	return reset_controller_register(&priv->rcdev);
90}
91
92static const struct of_device_id berlin_reset_dt_match[] = {
93	{ .compatible = "marvell,berlin2-reset" },
94	{ },
95};
96MODULE_DEVICE_TABLE(of, berlin_reset_dt_match);
97
98static struct platform_driver berlin_reset_driver = {
99	.probe	= berlin2_reset_probe,
100	.driver	= {
101		.name = "berlin2-reset",
102		.of_match_table = berlin_reset_dt_match,
103	},
104};
105module_platform_driver(berlin_reset_driver);
106
107MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
108MODULE_AUTHOR("Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>");
109MODULE_DESCRIPTION("Synaptics Berlin reset controller");
110MODULE_LICENSE("GPL");
111