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/mfd/syscon.h>
24 #include <linux/slab.h>
25
26 static struct platform_driver syscon_driver;
27
28 static DEFINE_SPINLOCK(syscon_list_slock);
29 static LIST_HEAD(syscon_list);
30
31 struct syscon {
32 struct device_node *np;
33 struct regmap *regmap;
34 struct list_head list;
35 };
36
37 static const struct regmap_config syscon_regmap_config = {
38 .reg_bits = 32,
39 .val_bits = 32,
40 .reg_stride = 4,
41 };
42
of_syscon_register(struct device_node * np,bool check_clk)43 static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
44 {
45 struct clk *clk;
46 struct syscon *syscon;
47 struct regmap *regmap;
48 void __iomem *base;
49 u32 reg_io_width;
50 int ret;
51 struct regmap_config syscon_config = syscon_regmap_config;
52 struct resource res;
53
54 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
55 if (!syscon)
56 return ERR_PTR(-ENOMEM);
57
58 if (of_address_to_resource(np, 0, &res)) {
59 ret = -ENOMEM;
60 goto err_map;
61 }
62
63 base = ioremap(res.start, resource_size(&res));
64 if (!base) {
65 ret = -ENOMEM;
66 goto err_map;
67 }
68
69 /* Parse the device's DT node for an endianness specification */
70 if (of_property_read_bool(np, "big-endian"))
71 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
72 else if (of_property_read_bool(np, "little-endian"))
73 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
74 else if (of_property_read_bool(np, "native-endian"))
75 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
76
77 /*
78 * search for reg-io-width property in DT. If it is not provided,
79 * default to 4 bytes. regmap_init_mmio will return an error if values
80 * are invalid so there is no need to check them here.
81 */
82 ret = of_property_read_u32(np, "reg-io-width", ®_io_width);
83 if (ret)
84 reg_io_width = 4;
85
86 ret = of_hwspin_lock_get_id(np, 0);
87 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
88 syscon_config.use_hwlock = true;
89 syscon_config.hwlock_id = ret;
90 syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
91 } else if (ret < 0) {
92 switch (ret) {
93 case -ENOENT:
94 /* Ignore missing hwlock, it's optional. */
95 break;
96 default:
97 pr_err("Failed to retrieve valid hwlock: %d\n", ret);
98 fallthrough;
99 case -EPROBE_DEFER:
100 goto err_regmap;
101 }
102 }
103
104 syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%llx", np,
105 (u64)res.start);
106 if (!syscon_config.name) {
107 ret = -ENOMEM;
108 goto err_regmap;
109 }
110 syscon_config.reg_stride = reg_io_width;
111 syscon_config.val_bits = reg_io_width * 8;
112 syscon_config.max_register = resource_size(&res) - reg_io_width;
113
114 regmap = regmap_init_mmio(NULL, base, &syscon_config);
115 kfree(syscon_config.name);
116 if (IS_ERR(regmap)) {
117 pr_err("regmap init failed\n");
118 ret = PTR_ERR(regmap);
119 goto err_regmap;
120 }
121
122 if (check_clk) {
123 clk = of_clk_get(np, 0);
124 if (IS_ERR(clk)) {
125 ret = PTR_ERR(clk);
126 /* clock is optional */
127 if (ret != -ENOENT)
128 goto err_clk;
129 } else {
130 ret = regmap_mmio_attach_clk(regmap, clk);
131 if (ret)
132 goto err_attach;
133 }
134 }
135
136 syscon->regmap = regmap;
137 syscon->np = np;
138
139 spin_lock(&syscon_list_slock);
140 list_add_tail(&syscon->list, &syscon_list);
141 spin_unlock(&syscon_list_slock);
142
143 return syscon;
144
145 err_attach:
146 if (!IS_ERR(clk))
147 clk_put(clk);
148 err_clk:
149 regmap_exit(regmap);
150 err_regmap:
151 iounmap(base);
152 err_map:
153 kfree(syscon);
154 return ERR_PTR(ret);
155 }
156
device_node_get_regmap(struct device_node * np,bool check_clk)157 static struct regmap *device_node_get_regmap(struct device_node *np,
158 bool check_clk)
159 {
160 struct syscon *entry, *syscon = NULL;
161
162 spin_lock(&syscon_list_slock);
163
164 list_for_each_entry(entry, &syscon_list, list)
165 if (entry->np == np) {
166 syscon = entry;
167 break;
168 }
169
170 spin_unlock(&syscon_list_slock);
171
172 if (!syscon)
173 syscon = of_syscon_register(np, check_clk);
174
175 if (IS_ERR(syscon))
176 return ERR_CAST(syscon);
177
178 return syscon->regmap;
179 }
180
device_node_to_regmap(struct device_node * np)181 struct regmap *device_node_to_regmap(struct device_node *np)
182 {
183 return device_node_get_regmap(np, false);
184 }
185 EXPORT_SYMBOL_GPL(device_node_to_regmap);
186
syscon_node_to_regmap(struct device_node * np)187 struct regmap *syscon_node_to_regmap(struct device_node *np)
188 {
189 if (!of_device_is_compatible(np, "syscon"))
190 return ERR_PTR(-EINVAL);
191
192 return device_node_get_regmap(np, true);
193 }
194 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
195
syscon_regmap_lookup_by_compatible(const char * s)196 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
197 {
198 struct device_node *syscon_np;
199 struct regmap *regmap;
200
201 syscon_np = of_find_compatible_node(NULL, NULL, s);
202 if (!syscon_np)
203 return ERR_PTR(-ENODEV);
204
205 regmap = syscon_node_to_regmap(syscon_np);
206 of_node_put(syscon_np);
207
208 return regmap;
209 }
210 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
211
syscon_regmap_lookup_by_phandle(struct device_node * np,const char * property)212 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
213 const char *property)
214 {
215 struct device_node *syscon_np;
216 struct regmap *regmap;
217
218 if (property)
219 syscon_np = of_parse_phandle(np, property, 0);
220 else
221 syscon_np = np;
222
223 if (!syscon_np)
224 return ERR_PTR(-ENODEV);
225
226 regmap = syscon_node_to_regmap(syscon_np);
227 of_node_put(syscon_np);
228
229 return regmap;
230 }
231 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
232
syscon_regmap_lookup_by_phandle_args(struct device_node * np,const char * property,int arg_count,unsigned int * out_args)233 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
234 const char *property,
235 int arg_count,
236 unsigned int *out_args)
237 {
238 struct device_node *syscon_np;
239 struct of_phandle_args args;
240 struct regmap *regmap;
241 unsigned int index;
242 int rc;
243
244 rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
245 0, &args);
246 if (rc)
247 return ERR_PTR(rc);
248
249 syscon_np = args.np;
250 if (!syscon_np)
251 return ERR_PTR(-ENODEV);
252
253 regmap = syscon_node_to_regmap(syscon_np);
254 for (index = 0; index < arg_count; index++)
255 out_args[index] = args.args[index];
256 of_node_put(syscon_np);
257
258 return regmap;
259 }
260 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
261
syscon_probe(struct platform_device * pdev)262 static int syscon_probe(struct platform_device *pdev)
263 {
264 struct device *dev = &pdev->dev;
265 struct syscon_platform_data *pdata = dev_get_platdata(dev);
266 struct syscon *syscon;
267 struct regmap_config syscon_config = syscon_regmap_config;
268 struct resource *res;
269 void __iomem *base;
270
271 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
272 if (!syscon)
273 return -ENOMEM;
274
275 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
276 if (!res)
277 return -ENOENT;
278
279 base = devm_ioremap(dev, res->start, resource_size(res));
280 if (!base)
281 return -ENOMEM;
282
283 syscon_config.max_register = resource_size(res) - 4;
284 if (pdata)
285 syscon_config.name = pdata->label;
286 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
287 if (IS_ERR(syscon->regmap)) {
288 dev_err(dev, "regmap init failed\n");
289 return PTR_ERR(syscon->regmap);
290 }
291
292 platform_set_drvdata(pdev, syscon);
293
294 dev_dbg(dev, "regmap %pR registered\n", res);
295
296 return 0;
297 }
298
299 static const struct platform_device_id syscon_ids[] = {
300 { "syscon", },
301 { }
302 };
303
304 static struct platform_driver syscon_driver = {
305 .driver = {
306 .name = "syscon",
307 },
308 .probe = syscon_probe,
309 .id_table = syscon_ids,
310 };
311
syscon_init(void)312 static int __init syscon_init(void)
313 {
314 return platform_driver_register(&syscon_driver);
315 }
316 postcore_initcall(syscon_init);
317