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/cleanup.h>
12 #include <linux/clk.h>
13 #include <linux/err.h>
14 #include <linux/hwspinlock.h>
15 #include <linux/io.h>
16 #include <linux/init.h>
17 #include <linux/list.h>
18 #include <linux/mutex.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/reset.h>
26 #include <linux/mfd/syscon.h>
27 #include <linux/slab.h>
28
29 static struct platform_driver syscon_driver;
30
31 static DEFINE_MUTEX(syscon_list_lock);
32 static LIST_HEAD(syscon_list);
33
34 struct syscon {
35 struct device_node *np;
36 struct regmap *regmap;
37 struct reset_control *reset;
38 struct list_head list;
39 };
40
41 static const struct regmap_config syscon_regmap_config = {
42 .reg_bits = 32,
43 .val_bits = 32,
44 .reg_stride = 4,
45 };
46
of_syscon_register(struct device_node * np,bool check_res)47 static struct syscon *of_syscon_register(struct device_node *np, bool check_res)
48 {
49 struct clk *clk;
50 struct regmap *regmap;
51 void __iomem *base;
52 u32 reg_io_width;
53 int ret;
54 struct regmap_config syscon_config = syscon_regmap_config;
55 struct resource res;
56 struct reset_control *reset;
57
58 WARN_ON(!mutex_is_locked(&syscon_list_lock));
59
60 struct syscon *syscon __free(kfree) = kzalloc(sizeof(*syscon), GFP_KERNEL);
61 if (!syscon)
62 return ERR_PTR(-ENOMEM);
63
64 if (of_address_to_resource(np, 0, &res))
65 return ERR_PTR(-ENOMEM);
66
67 base = of_iomap(np, 0);
68 if (!base)
69 return ERR_PTR(-ENOMEM);
70
71 /* Parse the device's DT node for an endianness specification */
72 if (of_property_read_bool(np, "big-endian"))
73 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
74 else if (of_property_read_bool(np, "little-endian"))
75 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
76 else if (of_property_read_bool(np, "native-endian"))
77 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
78
79 /*
80 * search for reg-io-width property in DT. If it is not provided,
81 * default to 4 bytes. regmap_init_mmio will return an error if values
82 * are invalid so there is no need to check them here.
83 */
84 ret = of_property_read_u32(np, "reg-io-width", ®_io_width);
85 if (ret)
86 reg_io_width = 4;
87
88 ret = of_hwspin_lock_get_id(np, 0);
89 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
90 syscon_config.use_hwlock = true;
91 syscon_config.hwlock_id = ret;
92 syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
93 } else if (ret < 0) {
94 switch (ret) {
95 case -ENOENT:
96 /* Ignore missing hwlock, it's optional. */
97 break;
98 default:
99 pr_err("Failed to retrieve valid hwlock: %d\n", ret);
100 fallthrough;
101 case -EPROBE_DEFER:
102 goto err_regmap;
103 }
104 }
105
106 syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start);
107 if (!syscon_config.name) {
108 ret = -ENOMEM;
109 goto err_regmap;
110 }
111 syscon_config.reg_stride = reg_io_width;
112 syscon_config.val_bits = reg_io_width * 8;
113 syscon_config.max_register = resource_size(&res) - reg_io_width;
114
115 regmap = regmap_init_mmio(NULL, base, &syscon_config);
116 kfree(syscon_config.name);
117 if (IS_ERR(regmap)) {
118 pr_err("regmap init failed\n");
119 ret = PTR_ERR(regmap);
120 goto err_regmap;
121 }
122
123 if (check_res) {
124 clk = of_clk_get(np, 0);
125 if (IS_ERR(clk)) {
126 ret = PTR_ERR(clk);
127 /* clock is optional */
128 if (ret != -ENOENT)
129 goto err_clk;
130 } else {
131 ret = regmap_mmio_attach_clk(regmap, clk);
132 if (ret)
133 goto err_attach_clk;
134 }
135
136 reset = of_reset_control_get_optional_exclusive(np, NULL);
137 if (IS_ERR(reset)) {
138 ret = PTR_ERR(reset);
139 goto err_attach_clk;
140 }
141
142 ret = reset_control_deassert(reset);
143 if (ret)
144 goto err_reset;
145 }
146
147 syscon->regmap = regmap;
148 syscon->np = np;
149
150 list_add_tail(&syscon->list, &syscon_list);
151
152 return_ptr(syscon);
153
154 err_reset:
155 reset_control_put(reset);
156 err_attach_clk:
157 if (!IS_ERR(clk))
158 clk_put(clk);
159 err_clk:
160 regmap_exit(regmap);
161 err_regmap:
162 iounmap(base);
163 return ERR_PTR(ret);
164 }
165
device_node_get_regmap(struct device_node * np,bool check_res)166 static struct regmap *device_node_get_regmap(struct device_node *np,
167 bool check_res)
168 {
169 struct syscon *entry, *syscon = NULL;
170
171 mutex_lock(&syscon_list_lock);
172
173 list_for_each_entry(entry, &syscon_list, list)
174 if (entry->np == np) {
175 syscon = entry;
176 break;
177 }
178
179 if (!syscon)
180 syscon = of_syscon_register(np, check_res);
181
182 mutex_unlock(&syscon_list_lock);
183
184 if (IS_ERR(syscon))
185 return ERR_CAST(syscon);
186
187 return syscon->regmap;
188 }
189
190 /**
191 * of_syscon_register_regmap() - Register regmap for specified device node
192 * @np: Device tree node
193 * @regmap: Pointer to regmap object
194 *
195 * Register an externally created regmap object with syscon for the specified
196 * device tree node. This regmap will then be returned to client drivers using
197 * the syscon_regmap_lookup_by_phandle() API.
198 *
199 * Return: 0 on success, negative error code on failure.
200 */
of_syscon_register_regmap(struct device_node * np,struct regmap * regmap)201 int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap)
202 {
203 struct syscon *entry, *syscon = NULL;
204 int ret;
205
206 if (!np || !regmap)
207 return -EINVAL;
208
209 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
210 if (!syscon)
211 return -ENOMEM;
212
213 /* check if syscon entry already exists */
214 mutex_lock(&syscon_list_lock);
215
216 list_for_each_entry(entry, &syscon_list, list)
217 if (entry->np == np) {
218 ret = -EEXIST;
219 goto err_unlock;
220 }
221
222 syscon->regmap = regmap;
223 syscon->np = np;
224
225 /* register the regmap in syscon list */
226 list_add_tail(&syscon->list, &syscon_list);
227 mutex_unlock(&syscon_list_lock);
228
229 return 0;
230
231 err_unlock:
232 mutex_unlock(&syscon_list_lock);
233 kfree(syscon);
234 return ret;
235 }
236 EXPORT_SYMBOL_GPL(of_syscon_register_regmap);
237
device_node_to_regmap(struct device_node * np)238 struct regmap *device_node_to_regmap(struct device_node *np)
239 {
240 return device_node_get_regmap(np, false);
241 }
242 EXPORT_SYMBOL_GPL(device_node_to_regmap);
243
syscon_node_to_regmap(struct device_node * np)244 struct regmap *syscon_node_to_regmap(struct device_node *np)
245 {
246 if (!of_device_is_compatible(np, "syscon"))
247 return ERR_PTR(-EINVAL);
248
249 return device_node_get_regmap(np, true);
250 }
251 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
252
syscon_regmap_lookup_by_compatible(const char * s)253 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
254 {
255 struct device_node *syscon_np;
256 struct regmap *regmap;
257
258 syscon_np = of_find_compatible_node(NULL, NULL, s);
259 if (!syscon_np)
260 return ERR_PTR(-ENODEV);
261
262 regmap = syscon_node_to_regmap(syscon_np);
263 of_node_put(syscon_np);
264
265 return regmap;
266 }
267 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
268
syscon_regmap_lookup_by_phandle(struct device_node * np,const char * property)269 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
270 const char *property)
271 {
272 struct device_node *syscon_np;
273 struct regmap *regmap;
274
275 if (property)
276 syscon_np = of_parse_phandle(np, property, 0);
277 else
278 syscon_np = np;
279
280 if (!syscon_np)
281 return ERR_PTR(-ENODEV);
282
283 regmap = syscon_node_to_regmap(syscon_np);
284
285 if (property)
286 of_node_put(syscon_np);
287
288 return regmap;
289 }
290 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
291
syscon_regmap_lookup_by_phandle_args(struct device_node * np,const char * property,int arg_count,unsigned int * out_args)292 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
293 const char *property,
294 int arg_count,
295 unsigned int *out_args)
296 {
297 struct device_node *syscon_np;
298 struct of_phandle_args args;
299 struct regmap *regmap;
300 unsigned int index;
301 int rc;
302
303 rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
304 0, &args);
305 if (rc)
306 return ERR_PTR(rc);
307
308 syscon_np = args.np;
309 if (!syscon_np)
310 return ERR_PTR(-ENODEV);
311
312 regmap = syscon_node_to_regmap(syscon_np);
313 for (index = 0; index < arg_count; index++)
314 out_args[index] = args.args[index];
315 of_node_put(syscon_np);
316
317 return regmap;
318 }
319 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
320
321 /*
322 * It behaves the same as syscon_regmap_lookup_by_phandle() except where
323 * there is no regmap phandle. In this case, instead of returning -ENODEV,
324 * the function returns NULL.
325 */
syscon_regmap_lookup_by_phandle_optional(struct device_node * np,const char * property)326 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
327 const char *property)
328 {
329 struct regmap *regmap;
330
331 regmap = syscon_regmap_lookup_by_phandle(np, property);
332 if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
333 return NULL;
334
335 return regmap;
336 }
337 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);
338
syscon_probe(struct platform_device * pdev)339 static int syscon_probe(struct platform_device *pdev)
340 {
341 struct device *dev = &pdev->dev;
342 struct syscon_platform_data *pdata = dev_get_platdata(dev);
343 struct syscon *syscon;
344 struct regmap_config syscon_config = syscon_regmap_config;
345 struct resource *res;
346 void __iomem *base;
347
348 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
349 if (!syscon)
350 return -ENOMEM;
351
352 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
353 if (!res)
354 return -ENOENT;
355
356 base = devm_ioremap(dev, res->start, resource_size(res));
357 if (!base)
358 return -ENOMEM;
359
360 syscon_config.max_register = resource_size(res) - 4;
361 if (pdata)
362 syscon_config.name = pdata->label;
363 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
364 if (IS_ERR(syscon->regmap)) {
365 dev_err(dev, "regmap init failed\n");
366 return PTR_ERR(syscon->regmap);
367 }
368
369 platform_set_drvdata(pdev, syscon);
370
371 dev_dbg(dev, "regmap %pR registered\n", res);
372
373 return 0;
374 }
375
376 static const struct platform_device_id syscon_ids[] = {
377 { "syscon", },
378 { }
379 };
380
381 static struct platform_driver syscon_driver = {
382 .driver = {
383 .name = "syscon",
384 },
385 .probe = syscon_probe,
386 .id_table = syscon_ids,
387 };
388
syscon_init(void)389 static int __init syscon_init(void)
390 {
391 return platform_driver_register(&syscon_driver);
392 }
393 postcore_initcall(syscon_init);
394