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 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
