1/*
2 * System Control Driver
3 *
4 * Copyright (C) 2012 Freescale Semiconductor, Inc.
5 * Copyright (C) 2012 Linaro Ltd.
6 *
7 * Author: Dong Aisheng <dong.aisheng@linaro.org>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 */
14
15#include <linux/err.h>
16#include <linux/io.h>
17#include <linux/module.h>
18#include <linux/list.h>
19#include <linux/of.h>
20#include <linux/of_address.h>
21#include <linux/of_platform.h>
22#include <linux/platform_data/syscon.h>
23#include <linux/platform_device.h>
24#include <linux/regmap.h>
25#include <linux/mfd/syscon.h>
26#include <linux/slab.h>
27
28static struct platform_driver syscon_driver;
29
30static DEFINE_SPINLOCK(syscon_list_slock);
31static LIST_HEAD(syscon_list);
32
33struct syscon {
34	struct device_node *np;
35	struct regmap *regmap;
36	struct list_head list;
37};
38
39static struct regmap_config syscon_regmap_config = {
40	.reg_bits = 32,
41	.val_bits = 32,
42	.reg_stride = 4,
43};
44
45static struct syscon *of_syscon_register(struct device_node *np)
46{
47	struct syscon *syscon;
48	struct regmap *regmap;
49	void __iomem *base;
50	int ret;
51	struct regmap_config syscon_config = syscon_regmap_config;
52
53	if (!of_device_is_compatible(np, "syscon"))
54		return ERR_PTR(-EINVAL);
55
56	syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
57	if (!syscon)
58		return ERR_PTR(-ENOMEM);
59
60	base = of_iomap(np, 0);
61	if (!base) {
62		ret = -ENOMEM;
63		goto err_map;
64	}
65
66	/* Parse the device's DT node for an endianness specification */
67	if (of_property_read_bool(np, "big-endian"))
68		syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
69	 else if (of_property_read_bool(np, "little-endian"))
70		syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
71
72	regmap = regmap_init_mmio(NULL, base, &syscon_config);
73	if (IS_ERR(regmap)) {
74		pr_err("regmap init failed\n");
75		ret = PTR_ERR(regmap);
76		goto err_regmap;
77	}
78
79	syscon->regmap = regmap;
80	syscon->np = np;
81
82	spin_lock(&syscon_list_slock);
83	list_add_tail(&syscon->list, &syscon_list);
84	spin_unlock(&syscon_list_slock);
85
86	return syscon;
87
88err_regmap:
89	iounmap(base);
90err_map:
91	kfree(syscon);
92	return ERR_PTR(ret);
93}
94
95struct regmap *syscon_node_to_regmap(struct device_node *np)
96{
97	struct syscon *entry, *syscon = NULL;
98
99	spin_lock(&syscon_list_slock);
100
101	list_for_each_entry(entry, &syscon_list, list)
102		if (entry->np == np) {
103			syscon = entry;
104			break;
105		}
106
107	spin_unlock(&syscon_list_slock);
108
109	if (!syscon)
110		syscon = of_syscon_register(np);
111
112	if (IS_ERR(syscon))
113		return ERR_CAST(syscon);
114
115	return syscon->regmap;
116}
117EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
118
119struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
120{
121	struct device_node *syscon_np;
122	struct regmap *regmap;
123
124	syscon_np = of_find_compatible_node(NULL, NULL, s);
125	if (!syscon_np)
126		return ERR_PTR(-ENODEV);
127
128	regmap = syscon_node_to_regmap(syscon_np);
129	of_node_put(syscon_np);
130
131	return regmap;
132}
133EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
134
135static int syscon_match_pdevname(struct device *dev, void *data)
136{
137	return !strcmp(dev_name(dev), (const char *)data);
138}
139
140struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
141{
142	struct device *dev;
143	struct syscon *syscon;
144
145	dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
146				 syscon_match_pdevname);
147	if (!dev)
148		return ERR_PTR(-EPROBE_DEFER);
149
150	syscon = dev_get_drvdata(dev);
151
152	return syscon->regmap;
153}
154EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
155
156struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
157					const char *property)
158{
159	struct device_node *syscon_np;
160	struct regmap *regmap;
161
162	if (property)
163		syscon_np = of_parse_phandle(np, property, 0);
164	else
165		syscon_np = np;
166
167	if (!syscon_np)
168		return ERR_PTR(-ENODEV);
169
170	regmap = syscon_node_to_regmap(syscon_np);
171	of_node_put(syscon_np);
172
173	return regmap;
174}
175EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
176
177static int syscon_probe(struct platform_device *pdev)
178{
179	struct device *dev = &pdev->dev;
180	struct syscon_platform_data *pdata = dev_get_platdata(dev);
181	struct syscon *syscon;
182	struct resource *res;
183	void __iomem *base;
184
185	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
186	if (!syscon)
187		return -ENOMEM;
188
189	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
190	if (!res)
191		return -ENOENT;
192
193	base = devm_ioremap(dev, res->start, resource_size(res));
194	if (!base)
195		return -ENOMEM;
196
197	syscon_regmap_config.max_register = res->end - res->start - 3;
198	if (pdata)
199		syscon_regmap_config.name = pdata->label;
200	syscon->regmap = devm_regmap_init_mmio(dev, base,
201					&syscon_regmap_config);
202	if (IS_ERR(syscon->regmap)) {
203		dev_err(dev, "regmap init failed\n");
204		return PTR_ERR(syscon->regmap);
205	}
206
207	platform_set_drvdata(pdev, syscon);
208
209	dev_dbg(dev, "regmap %pR registered\n", res);
210
211	return 0;
212}
213
214static const struct platform_device_id syscon_ids[] = {
215	{ "syscon", },
216	{ }
217};
218
219static struct platform_driver syscon_driver = {
220	.driver = {
221		.name = "syscon",
222	},
223	.probe		= syscon_probe,
224	.id_table	= syscon_ids,
225};
226
227static int __init syscon_init(void)
228{
229	return platform_driver_register(&syscon_driver);
230}
231postcore_initcall(syscon_init);
232
233static void __exit syscon_exit(void)
234{
235	platform_driver_unregister(&syscon_driver);
236}
237module_exit(syscon_exit);
238
239MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
240MODULE_DESCRIPTION("System Control driver");
241MODULE_LICENSE("GPL v2");
242