1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * System Control Driver
4 *
5 * Copyright (C) 2012 Freescale Semiconductor, Inc.
6 * Copyright (C) 2012 Linaro Ltd.
7 *
8 * Author: Dong Aisheng <dong.aisheng@linaro.org>
9 */
10
11#include <linux/clk.h>
12#include <linux/err.h>
13#include <linux/hwspinlock.h>
14#include <linux/io.h>
15#include <linux/init.h>
16#include <linux/list.h>
17#include <linux/of.h>
18#include <linux/of_address.h>
19#include <linux/of_platform.h>
20#include <linux/platform_data/syscon.h>
21#include <linux/platform_device.h>
22#include <linux/regmap.h>
23#include <linux/reset.h>
24#include <linux/mfd/syscon.h>
25#include <linux/slab.h>
26
27static struct platform_driver syscon_driver;
28
29static DEFINE_SPINLOCK(syscon_list_slock);
30static LIST_HEAD(syscon_list);
31
32struct syscon {
33	struct device_node *np;
34	struct regmap *regmap;
35	struct reset_control *reset;
36	struct list_head list;
37};
38
39static const 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, bool check_res)
46{
47	struct clk *clk;
48	struct syscon *syscon;
49	struct regmap *regmap;
50	void __iomem *base;
51	u32 reg_io_width;
52	int ret;
53	struct regmap_config syscon_config = syscon_regmap_config;
54	struct resource res;
55	struct reset_control *reset;
56
57	syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
58	if (!syscon)
59		return ERR_PTR(-ENOMEM);
60
61	if (of_address_to_resource(np, 0, &res)) {
62		ret = -ENOMEM;
63		goto err_map;
64	}
65
66	base = of_iomap(np, 0);
67	if (!base) {
68		ret = -ENOMEM;
69		goto err_map;
70	}
71
72	/* Parse the device's DT node for an endianness specification */
73	if (of_property_read_bool(np, "big-endian"))
74		syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
75	else if (of_property_read_bool(np, "little-endian"))
76		syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
77	else if (of_property_read_bool(np, "native-endian"))
78		syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
79
80	/*
81	 * search for reg-io-width property in DT. If it is not provided,
82	 * default to 4 bytes. regmap_init_mmio will return an error if values
83	 * are invalid so there is no need to check them here.
84	 */
85	ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
86	if (ret)
87		reg_io_width = 4;
88
89	ret = of_hwspin_lock_get_id(np, 0);
90	if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
91		syscon_config.use_hwlock = true;
92		syscon_config.hwlock_id = ret;
93		syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
94	} else if (ret < 0) {
95		switch (ret) {
96		case -ENOENT:
97			/* Ignore missing hwlock, it's optional. */
98			break;
99		default:
100			pr_err("Failed to retrieve valid hwlock: %d\n", ret);
101			fallthrough;
102		case -EPROBE_DEFER:
103			goto err_regmap;
104		}
105	}
106
107	syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start);
108	if (!syscon_config.name) {
109		ret = -ENOMEM;
110		goto err_regmap;
111	}
112	syscon_config.reg_stride = reg_io_width;
113	syscon_config.val_bits = reg_io_width * 8;
114	syscon_config.max_register = resource_size(&res) - reg_io_width;
115
116	regmap = regmap_init_mmio(NULL, base, &syscon_config);
117	kfree(syscon_config.name);
118	if (IS_ERR(regmap)) {
119		pr_err("regmap init failed\n");
120		ret = PTR_ERR(regmap);
121		goto err_regmap;
122	}
123
124	if (check_res) {
125		clk = of_clk_get(np, 0);
126		if (IS_ERR(clk)) {
127			ret = PTR_ERR(clk);
128			/* clock is optional */
129			if (ret != -ENOENT)
130				goto err_clk;
131		} else {
132			ret = regmap_mmio_attach_clk(regmap, clk);
133			if (ret)
134				goto err_attach_clk;
135		}
136
137		reset = of_reset_control_get_optional_exclusive(np, NULL);
138		if (IS_ERR(reset)) {
139			ret = PTR_ERR(reset);
140			goto err_attach_clk;
141		}
142
143		ret = reset_control_deassert(reset);
144		if (ret)
145			goto err_reset;
146	}
147
148	syscon->regmap = regmap;
149	syscon->np = np;
150
151	spin_lock(&syscon_list_slock);
152	list_add_tail(&syscon->list, &syscon_list);
153	spin_unlock(&syscon_list_slock);
154
155	return syscon;
156
157err_reset:
158	reset_control_put(reset);
159err_attach_clk:
160	if (!IS_ERR(clk))
161		clk_put(clk);
162err_clk:
163	regmap_exit(regmap);
164err_regmap:
165	iounmap(base);
166err_map:
167	kfree(syscon);
168	return ERR_PTR(ret);
169}
170
171static struct regmap *device_node_get_regmap(struct device_node *np,
172					     bool check_res)
173{
174	struct syscon *entry, *syscon = NULL;
175
176	spin_lock(&syscon_list_slock);
177
178	list_for_each_entry(entry, &syscon_list, list)
179		if (entry->np == np) {
180			syscon = entry;
181			break;
182		}
183
184	spin_unlock(&syscon_list_slock);
185
186	if (!syscon)
187		syscon = of_syscon_register(np, check_res);
188
189	if (IS_ERR(syscon))
190		return ERR_CAST(syscon);
191
192	return syscon->regmap;
193}
194
195struct regmap *device_node_to_regmap(struct device_node *np)
196{
197	return device_node_get_regmap(np, false);
198}
199EXPORT_SYMBOL_GPL(device_node_to_regmap);
200
201struct regmap *syscon_node_to_regmap(struct device_node *np)
202{
203	if (!of_device_is_compatible(np, "syscon"))
204		return ERR_PTR(-EINVAL);
205
206	return device_node_get_regmap(np, true);
207}
208EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
209
210struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
211{
212	struct device_node *syscon_np;
213	struct regmap *regmap;
214
215	syscon_np = of_find_compatible_node(NULL, NULL, s);
216	if (!syscon_np)
217		return ERR_PTR(-ENODEV);
218
219	regmap = syscon_node_to_regmap(syscon_np);
220	of_node_put(syscon_np);
221
222	return regmap;
223}
224EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
225
226struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
227					const char *property)
228{
229	struct device_node *syscon_np;
230	struct regmap *regmap;
231
232	if (property)
233		syscon_np = of_parse_phandle(np, property, 0);
234	else
235		syscon_np = np;
236
237	if (!syscon_np)
238		return ERR_PTR(-ENODEV);
239
240	regmap = syscon_node_to_regmap(syscon_np);
241
242	if (property)
243		of_node_put(syscon_np);
244
245	return regmap;
246}
247EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
248
249struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
250					const char *property,
251					int arg_count,
252					unsigned int *out_args)
253{
254	struct device_node *syscon_np;
255	struct of_phandle_args args;
256	struct regmap *regmap;
257	unsigned int index;
258	int rc;
259
260	rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
261			0, &args);
262	if (rc)
263		return ERR_PTR(rc);
264
265	syscon_np = args.np;
266	if (!syscon_np)
267		return ERR_PTR(-ENODEV);
268
269	regmap = syscon_node_to_regmap(syscon_np);
270	for (index = 0; index < arg_count; index++)
271		out_args[index] = args.args[index];
272	of_node_put(syscon_np);
273
274	return regmap;
275}
276EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
277
278/*
279 * It behaves the same as syscon_regmap_lookup_by_phandle() except where
280 * there is no regmap phandle. In this case, instead of returning -ENODEV,
281 * the function returns NULL.
282 */
283struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
284					const char *property)
285{
286	struct regmap *regmap;
287
288	regmap = syscon_regmap_lookup_by_phandle(np, property);
289	if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
290		return NULL;
291
292	return regmap;
293}
294EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);
295
296static int syscon_probe(struct platform_device *pdev)
297{
298	struct device *dev = &pdev->dev;
299	struct syscon_platform_data *pdata = dev_get_platdata(dev);
300	struct syscon *syscon;
301	struct regmap_config syscon_config = syscon_regmap_config;
302	struct resource *res;
303	void __iomem *base;
304
305	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
306	if (!syscon)
307		return -ENOMEM;
308
309	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
310	if (!res)
311		return -ENOENT;
312
313	base = devm_ioremap(dev, res->start, resource_size(res));
314	if (!base)
315		return -ENOMEM;
316
317	syscon_config.max_register = resource_size(res) - 4;
318	if (pdata)
319		syscon_config.name = pdata->label;
320	syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
321	if (IS_ERR(syscon->regmap)) {
322		dev_err(dev, "regmap init failed\n");
323		return PTR_ERR(syscon->regmap);
324	}
325
326	platform_set_drvdata(pdev, syscon);
327
328	dev_dbg(dev, "regmap %pR registered\n", res);
329
330	return 0;
331}
332
333static const struct platform_device_id syscon_ids[] = {
334	{ "syscon", },
335	{ }
336};
337
338static struct platform_driver syscon_driver = {
339	.driver = {
340		.name = "syscon",
341	},
342	.probe		= syscon_probe,
343	.id_table	= syscon_ids,
344};
345
346static int __init syscon_init(void)
347{
348	return platform_driver_register(&syscon_driver);
349}
350postcore_initcall(syscon_init);
351