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", ®_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
157 err_reset:
158 reset_control_put(reset);
159 err_attach_clk:
160 if (!IS_ERR(clk))
161 clk_put(clk);
162 err_clk:
163 regmap_exit(regmap);
164 err_regmap:
165 iounmap(base);
166 err_map:
167 kfree(syscon);
168 return ERR_PTR(ret);
169 }
170
device_node_get_regmap(struct device_node * np,bool check_res)171 static 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
device_node_to_regmap(struct device_node * np)195 struct regmap *device_node_to_regmap(struct device_node *np)
196 {
197 return device_node_get_regmap(np, false);
198 }
199 EXPORT_SYMBOL_GPL(device_node_to_regmap);
200
syscon_node_to_regmap(struct device_node * np)201 struct 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 }
208 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
209
syscon_regmap_lookup_by_compatible(const char * s)210 struct 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 }
224 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
225
syscon_regmap_lookup_by_phandle(struct device_node * np,const char * property)226 struct 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 }
247 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
248
syscon_regmap_lookup_by_phandle_args(struct device_node * np,const char * property,int arg_count,unsigned int * out_args)249 struct 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 }
276 EXPORT_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 */
syscon_regmap_lookup_by_phandle_optional(struct device_node * np,const char * property)283 struct 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 }
294 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);
295
syscon_probe(struct platform_device * pdev)296 static 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
333 static const struct platform_device_id syscon_ids[] = {
334 { "syscon", },
335 { }
336 };
337
338 static struct platform_driver syscon_driver = {
339 .driver = {
340 .name = "syscon",
341 },
342 .probe = syscon_probe,
343 .id_table = syscon_ids,
344 };
345
syscon_init(void)346 static int __init syscon_init(void)
347 {
348 return platform_driver_register(&syscon_driver);
349 }
350 postcore_initcall(syscon_init);
351