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 #include <trace/hooks/regmap.h>
29
30 static struct platform_driver syscon_driver;
31
32 static DEFINE_MUTEX(syscon_list_lock);
33 static LIST_HEAD(syscon_list);
34
35 struct syscon {
36 struct device_node *np;
37 struct regmap *regmap;
38 struct reset_control *reset;
39 struct list_head list;
40 };
41
42 static const struct regmap_config syscon_regmap_config = {
43 .reg_bits = 32,
44 .val_bits = 32,
45 .reg_stride = 4,
46 };
47
of_syscon_register(struct device_node * np,bool check_res)48 static struct syscon *of_syscon_register(struct device_node *np, bool check_res)
49 {
50 struct clk *clk;
51 struct regmap *regmap;
52 void __iomem *base;
53 u32 reg_io_width;
54 int ret;
55 struct regmap_config syscon_config = syscon_regmap_config;
56 struct resource res;
57 struct reset_control *reset;
58
59 WARN_ON(!mutex_is_locked(&syscon_list_lock));
60
61 struct syscon *syscon __free(kfree) = kzalloc(sizeof(*syscon), GFP_KERNEL);
62 if (!syscon)
63 return ERR_PTR(-ENOMEM);
64
65 if (of_address_to_resource(np, 0, &res))
66 return ERR_PTR(-ENOMEM);
67
68 base = of_iomap(np, 0);
69 if (!base)
70 return ERR_PTR(-ENOMEM);
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", ®_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 trace_android_vh_regmap_update(&syscon_config, regmap);
149 syscon->regmap = regmap;
150 syscon->np = np;
151
152 list_add_tail(&syscon->list, &syscon_list);
153
154 return_ptr(syscon);
155
156 err_reset:
157 reset_control_put(reset);
158 err_attach_clk:
159 if (!IS_ERR(clk))
160 clk_put(clk);
161 err_clk:
162 regmap_exit(regmap);
163 err_regmap:
164 iounmap(base);
165 return ERR_PTR(ret);
166 }
167
device_node_get_regmap(struct device_node * np,bool check_res)168 static struct regmap *device_node_get_regmap(struct device_node *np,
169 bool check_res)
170 {
171 struct syscon *entry, *syscon = NULL;
172
173 mutex_lock(&syscon_list_lock);
174
175 list_for_each_entry(entry, &syscon_list, list)
176 if (entry->np == np) {
177 syscon = entry;
178 break;
179 }
180
181 if (!syscon)
182 syscon = of_syscon_register(np, check_res);
183
184 mutex_unlock(&syscon_list_lock);
185
186 if (IS_ERR(syscon))
187 return ERR_CAST(syscon);
188
189 return syscon->regmap;
190 }
191
192 /**
193 * of_syscon_register_regmap() - Register regmap for specified device node
194 * @np: Device tree node
195 * @regmap: Pointer to regmap object
196 *
197 * Register an externally created regmap object with syscon for the specified
198 * device tree node. This regmap will then be returned to client drivers using
199 * the syscon_regmap_lookup_by_phandle() API.
200 *
201 * Return: 0 on success, negative error code on failure.
202 */
of_syscon_register_regmap(struct device_node * np,struct regmap * regmap)203 int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap)
204 {
205 struct syscon *entry, *syscon = NULL;
206 int ret;
207
208 if (!np || !regmap)
209 return -EINVAL;
210
211 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
212 if (!syscon)
213 return -ENOMEM;
214
215 /* check if syscon entry already exists */
216 mutex_lock(&syscon_list_lock);
217
218 list_for_each_entry(entry, &syscon_list, list)
219 if (entry->np == np) {
220 ret = -EEXIST;
221 goto err_unlock;
222 }
223
224 syscon->regmap = regmap;
225 syscon->np = np;
226
227 /* register the regmap in syscon list */
228 list_add_tail(&syscon->list, &syscon_list);
229 mutex_unlock(&syscon_list_lock);
230
231 return 0;
232
233 err_unlock:
234 mutex_unlock(&syscon_list_lock);
235 kfree(syscon);
236 return ret;
237 }
238 EXPORT_SYMBOL_GPL(of_syscon_register_regmap);
239
device_node_to_regmap(struct device_node * np)240 struct regmap *device_node_to_regmap(struct device_node *np)
241 {
242 return device_node_get_regmap(np, false);
243 }
244 EXPORT_SYMBOL_GPL(device_node_to_regmap);
245
syscon_node_to_regmap(struct device_node * np)246 struct regmap *syscon_node_to_regmap(struct device_node *np)
247 {
248 if (!of_device_is_compatible(np, "syscon"))
249 return ERR_PTR(-EINVAL);
250
251 return device_node_get_regmap(np, true);
252 }
253 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
254
syscon_regmap_lookup_by_compatible(const char * s)255 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
256 {
257 struct device_node *syscon_np;
258 struct regmap *regmap;
259
260 syscon_np = of_find_compatible_node(NULL, NULL, s);
261 if (!syscon_np)
262 return ERR_PTR(-ENODEV);
263
264 regmap = syscon_node_to_regmap(syscon_np);
265 of_node_put(syscon_np);
266
267 return regmap;
268 }
269 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
270
syscon_regmap_lookup_by_phandle(struct device_node * np,const char * property)271 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
272 const char *property)
273 {
274 struct device_node *syscon_np;
275 struct regmap *regmap;
276
277 if (property)
278 syscon_np = of_parse_phandle(np, property, 0);
279 else
280 syscon_np = np;
281
282 if (!syscon_np)
283 return ERR_PTR(-ENODEV);
284
285 regmap = syscon_node_to_regmap(syscon_np);
286
287 if (property)
288 of_node_put(syscon_np);
289
290 return regmap;
291 }
292 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
293
syscon_regmap_lookup_by_phandle_args(struct device_node * np,const char * property,int arg_count,unsigned int * out_args)294 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
295 const char *property,
296 int arg_count,
297 unsigned int *out_args)
298 {
299 struct device_node *syscon_np;
300 struct of_phandle_args args;
301 struct regmap *regmap;
302 unsigned int index;
303 int rc;
304
305 rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
306 0, &args);
307 if (rc)
308 return ERR_PTR(rc);
309
310 syscon_np = args.np;
311 if (!syscon_np)
312 return ERR_PTR(-ENODEV);
313
314 regmap = syscon_node_to_regmap(syscon_np);
315 for (index = 0; index < arg_count; index++)
316 out_args[index] = args.args[index];
317 of_node_put(syscon_np);
318
319 return regmap;
320 }
321 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
322
323 /*
324 * It behaves the same as syscon_regmap_lookup_by_phandle() except where
325 * there is no regmap phandle. In this case, instead of returning -ENODEV,
326 * the function returns NULL.
327 */
syscon_regmap_lookup_by_phandle_optional(struct device_node * np,const char * property)328 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
329 const char *property)
330 {
331 struct regmap *regmap;
332
333 regmap = syscon_regmap_lookup_by_phandle(np, property);
334 if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
335 return NULL;
336
337 return regmap;
338 }
339 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);
340
syscon_probe(struct platform_device * pdev)341 static int syscon_probe(struct platform_device *pdev)
342 {
343 struct device *dev = &pdev->dev;
344 struct syscon_platform_data *pdata = dev_get_platdata(dev);
345 struct syscon *syscon;
346 struct regmap_config syscon_config = syscon_regmap_config;
347 struct resource *res;
348 void __iomem *base;
349
350 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
351 if (!syscon)
352 return -ENOMEM;
353
354 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
355 if (!res)
356 return -ENOENT;
357
358 base = devm_ioremap(dev, res->start, resource_size(res));
359 if (!base)
360 return -ENOMEM;
361
362 syscon_config.max_register = resource_size(res) - 4;
363 if (pdata)
364 syscon_config.name = pdata->label;
365 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
366 if (IS_ERR(syscon->regmap)) {
367 dev_err(dev, "regmap init failed\n");
368 return PTR_ERR(syscon->regmap);
369 }
370
371 platform_set_drvdata(pdev, syscon);
372
373 dev_dbg(dev, "regmap %pR registered\n", res);
374
375 return 0;
376 }
377
378 static const struct platform_device_id syscon_ids[] = {
379 { "syscon", },
380 { }
381 };
382
383 static struct platform_driver syscon_driver = {
384 .driver = {
385 .name = "syscon",
386 },
387 .probe = syscon_probe,
388 .id_table = syscon_ids,
389 };
390
syscon_init(void)391 static int __init syscon_init(void)
392 {
393 return platform_driver_register(&syscon_driver);
394 }
395 postcore_initcall(syscon_init);
396