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