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 
27 static struct platform_driver syscon_driver;
28 
29 static DEFINE_SPINLOCK(syscon_list_slock);
30 static LIST_HEAD(syscon_list);
31 
32 struct syscon {
33 	struct device_node *np;
34 	struct regmap *regmap;
35 	struct reset_control *reset;
36 	struct list_head list;
37 };
38 
39 static const struct regmap_config syscon_regmap_config = {
40 	.reg_bits = 32,
41 	.val_bits = 32,
42 	.reg_stride = 4,
43 };
44 
of_syscon_register(struct device_node * np,bool check_res)45 static 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 	syscon_config.reg_stride = reg_io_width;
109 	syscon_config.val_bits = reg_io_width * 8;
110 	syscon_config.max_register = resource_size(&res) - reg_io_width;
111 
112 	regmap = regmap_init_mmio(NULL, base, &syscon_config);
113 	kfree(syscon_config.name);
114 	if (IS_ERR(regmap)) {
115 		pr_err("regmap init failed\n");
116 		ret = PTR_ERR(regmap);
117 		goto err_regmap;
118 	}
119 
120 	if (check_res) {
121 		clk = of_clk_get(np, 0);
122 		if (IS_ERR(clk)) {
123 			ret = PTR_ERR(clk);
124 			/* clock is optional */
125 			if (ret != -ENOENT)
126 				goto err_clk;
127 		} else {
128 			ret = regmap_mmio_attach_clk(regmap, clk);
129 			if (ret)
130 				goto err_attach_clk;
131 		}
132 
133 		reset = of_reset_control_get_optional_exclusive(np, NULL);
134 		if (IS_ERR(reset)) {
135 			ret = PTR_ERR(reset);
136 			goto err_attach_clk;
137 		}
138 
139 		ret = reset_control_deassert(reset);
140 		if (ret)
141 			goto err_reset;
142 	}
143 
144 	syscon->regmap = regmap;
145 	syscon->np = np;
146 
147 	spin_lock(&syscon_list_slock);
148 	list_add_tail(&syscon->list, &syscon_list);
149 	spin_unlock(&syscon_list_slock);
150 
151 	return syscon;
152 
153 err_reset:
154 	reset_control_put(reset);
155 err_attach_clk:
156 	if (!IS_ERR(clk))
157 		clk_put(clk);
158 err_clk:
159 	regmap_exit(regmap);
160 err_regmap:
161 	iounmap(base);
162 err_map:
163 	kfree(syscon);
164 	return ERR_PTR(ret);
165 }
166 
device_node_get_regmap(struct device_node * np,bool check_res)167 static struct regmap *device_node_get_regmap(struct device_node *np,
168 					     bool check_res)
169 {
170 	struct syscon *entry, *syscon = NULL;
171 
172 	spin_lock(&syscon_list_slock);
173 
174 	list_for_each_entry(entry, &syscon_list, list)
175 		if (entry->np == np) {
176 			syscon = entry;
177 			break;
178 		}
179 
180 	spin_unlock(&syscon_list_slock);
181 
182 	if (!syscon)
183 		syscon = of_syscon_register(np, check_res);
184 
185 	if (IS_ERR(syscon))
186 		return ERR_CAST(syscon);
187 
188 	return syscon->regmap;
189 }
190 
device_node_to_regmap(struct device_node * np)191 struct regmap *device_node_to_regmap(struct device_node *np)
192 {
193 	return device_node_get_regmap(np, false);
194 }
195 EXPORT_SYMBOL_GPL(device_node_to_regmap);
196 
syscon_node_to_regmap(struct device_node * np)197 struct regmap *syscon_node_to_regmap(struct device_node *np)
198 {
199 	if (!of_device_is_compatible(np, "syscon"))
200 		return ERR_PTR(-EINVAL);
201 
202 	return device_node_get_regmap(np, true);
203 }
204 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
205 
syscon_regmap_lookup_by_compatible(const char * s)206 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
207 {
208 	struct device_node *syscon_np;
209 	struct regmap *regmap;
210 
211 	syscon_np = of_find_compatible_node(NULL, NULL, s);
212 	if (!syscon_np)
213 		return ERR_PTR(-ENODEV);
214 
215 	regmap = syscon_node_to_regmap(syscon_np);
216 	of_node_put(syscon_np);
217 
218 	return regmap;
219 }
220 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
221 
syscon_regmap_lookup_by_phandle(struct device_node * np,const char * property)222 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
223 					const char *property)
224 {
225 	struct device_node *syscon_np;
226 	struct regmap *regmap;
227 
228 	if (property)
229 		syscon_np = of_parse_phandle(np, property, 0);
230 	else
231 		syscon_np = np;
232 
233 	if (!syscon_np)
234 		return ERR_PTR(-ENODEV);
235 
236 	regmap = syscon_node_to_regmap(syscon_np);
237 	of_node_put(syscon_np);
238 
239 	return regmap;
240 }
241 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
242 
syscon_regmap_lookup_by_phandle_args(struct device_node * np,const char * property,int arg_count,unsigned int * out_args)243 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
244 					const char *property,
245 					int arg_count,
246 					unsigned int *out_args)
247 {
248 	struct device_node *syscon_np;
249 	struct of_phandle_args args;
250 	struct regmap *regmap;
251 	unsigned int index;
252 	int rc;
253 
254 	rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
255 			0, &args);
256 	if (rc)
257 		return ERR_PTR(rc);
258 
259 	syscon_np = args.np;
260 	if (!syscon_np)
261 		return ERR_PTR(-ENODEV);
262 
263 	regmap = syscon_node_to_regmap(syscon_np);
264 	for (index = 0; index < arg_count; index++)
265 		out_args[index] = args.args[index];
266 	of_node_put(syscon_np);
267 
268 	return regmap;
269 }
270 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
271 
272 /*
273  * It behaves the same as syscon_regmap_lookup_by_phandle() except where
274  * there is no regmap phandle. In this case, instead of returning -ENODEV,
275  * the function returns NULL.
276  */
syscon_regmap_lookup_by_phandle_optional(struct device_node * np,const char * property)277 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
278 					const char *property)
279 {
280 	struct regmap *regmap;
281 
282 	regmap = syscon_regmap_lookup_by_phandle(np, property);
283 	if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
284 		return NULL;
285 
286 	return regmap;
287 }
288 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);
289 
syscon_probe(struct platform_device * pdev)290 static int syscon_probe(struct platform_device *pdev)
291 {
292 	struct device *dev = &pdev->dev;
293 	struct syscon_platform_data *pdata = dev_get_platdata(dev);
294 	struct syscon *syscon;
295 	struct regmap_config syscon_config = syscon_regmap_config;
296 	struct resource *res;
297 	void __iomem *base;
298 
299 	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
300 	if (!syscon)
301 		return -ENOMEM;
302 
303 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
304 	if (!res)
305 		return -ENOENT;
306 
307 	base = devm_ioremap(dev, res->start, resource_size(res));
308 	if (!base)
309 		return -ENOMEM;
310 
311 	syscon_config.max_register = resource_size(res) - 4;
312 	if (pdata)
313 		syscon_config.name = pdata->label;
314 	syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
315 	if (IS_ERR(syscon->regmap)) {
316 		dev_err(dev, "regmap init failed\n");
317 		return PTR_ERR(syscon->regmap);
318 	}
319 
320 	platform_set_drvdata(pdev, syscon);
321 
322 	dev_dbg(dev, "regmap %pR registered\n", res);
323 
324 	return 0;
325 }
326 
327 static const struct platform_device_id syscon_ids[] = {
328 	{ "syscon", },
329 	{ }
330 };
331 
332 static struct platform_driver syscon_driver = {
333 	.driver = {
334 		.name = "syscon",
335 	},
336 	.probe		= syscon_probe,
337 	.id_table	= syscon_ids,
338 };
339 
syscon_init(void)340 static int __init syscon_init(void)
341 {
342 	return platform_driver_register(&syscon_driver);
343 }
344 postcore_initcall(syscon_init);
345