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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 <[email protected]>
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/list.h>
16#include <linux/mutex.h>
17#include <linux/of.h>
18#include <linux/of_address.h>
19#include <linux/regmap.h>
20#include <linux/reset.h>
21#include <linux/mfd/syscon.h>
22#include <linux/slab.h>
23
24static DEFINE_MUTEX(syscon_list_lock);
25static LIST_HEAD(syscon_list);
26
27struct syscon {
28 struct device_node *np;
29 struct regmap *regmap;
30 struct reset_control *reset;
31 struct list_head list;
32};
33
34static const struct regmap_config syscon_regmap_config = {
35 .reg_bits = 32,
36 .val_bits = 32,
37 .reg_stride = 4,
38};
39
40static struct syscon *of_syscon_register(struct device_node *np, bool check_res)
41{
42 struct clk *clk;
43 struct regmap *regmap;
44 void __iomem *base;
45 u32 reg_io_width;
46 int ret;
47 struct regmap_config syscon_config = syscon_regmap_config;
48 struct resource res;
49 struct reset_control *reset;
50 resource_size_t res_size;
51
52 WARN_ON(!mutex_is_locked(&syscon_list_lock));
53
54 struct syscon *syscon __free(kfree) = kzalloc_obj(*syscon);
55 if (!syscon)
56 return ERR_PTR(-ENOMEM);
57
58 if (of_address_to_resource(np, 0, &res))
59 return ERR_PTR(-ENOMEM);
60
61 base = of_iomap(np, 0);
62 if (!base)
63 return ERR_PTR(-ENOMEM);
64
65 /* Parse the device's DT node for an endianness specification */
66 if (of_property_read_bool(np, "big-endian"))
67 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
68 else if (of_property_read_bool(np, "little-endian"))
69 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
70 else if (of_property_read_bool(np, "native-endian"))
71 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
72
73 /*
74 * search for reg-io-width property in DT. If it is not provided,
75 * default to 4 bytes. regmap_init_mmio will return an error if values
76 * are invalid so there is no need to check them here.
77 */
78 ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
79 if (ret)
80 reg_io_width = 4;
81
82 ret = of_hwspin_lock_get_id(np, 0);
83 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
84 syscon_config.use_hwlock = true;
85 syscon_config.hwlock_id = ret;
86 syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
87 } else if (ret < 0) {
88 switch (ret) {
89 case -ENOENT:
90 /* Ignore missing hwlock, it's optional. */
91 break;
92 default:
93 pr_err("Failed to retrieve valid hwlock: %d\n", ret);
94 fallthrough;
95 case -EPROBE_DEFER:
96 goto err_regmap;
97 }
98 }
99
100 res_size = resource_size(&res);
101 if (res_size < reg_io_width) {
102 ret = -EFAULT;
103 goto err_regmap;
104 }
105
106 syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start);
107 if (!syscon_config.name) {
108 ret = -ENOMEM;
109 goto err_regmap;
110 }
111 syscon_config.reg_stride = reg_io_width;
112 syscon_config.val_bits = reg_io_width * 8;
113 syscon_config.max_register = res_size - reg_io_width;
114 if (!syscon_config.max_register)
115 syscon_config.max_register_is_0 = true;
116
117 regmap = regmap_init_mmio(NULL, base, &syscon_config);
118 kfree(syscon_config.name);
119 if (IS_ERR(regmap)) {
120 pr_err("regmap init failed\n");
121 ret = PTR_ERR(regmap);
122 goto err_regmap;
123 }
124
125 if (check_res) {
126 clk = of_clk_get(np, 0);
127 if (IS_ERR(clk)) {
128 ret = PTR_ERR(clk);
129 /* clock is optional */
130 if (ret != -ENOENT)
131 goto err_clk;
132 } else {
133 ret = regmap_mmio_attach_clk(regmap, clk);
134 if (ret)
135 goto err_attach_clk;
136 }
137
138 reset = of_reset_control_get_optional_exclusive(np, NULL);
139 if (IS_ERR(reset)) {
140 ret = PTR_ERR(reset);
141 goto err_attach_clk;
142 }
143
144 ret = reset_control_deassert(reset);
145 if (ret)
146 goto err_reset;
147 }
148
149 syscon->regmap = regmap;
150 syscon->np = np;
151
152 list_add_tail(&syscon->list, &syscon_list);
153
154 return_ptr(syscon);
155
156err_reset:
157 reset_control_put(reset);
158err_attach_clk:
159 if (!IS_ERR(clk))
160 clk_put(clk);
161err_clk:
162 regmap_exit(regmap);
163err_regmap:
164 iounmap(base);
165 return ERR_PTR(ret);
166}
167
168static struct regmap *device_node_get_regmap(struct device_node *np,
169 bool create_regmap,
170 bool check_res)
171{
172 struct syscon *entry, *syscon = NULL;
173
174 mutex_lock(&syscon_list_lock);
175
176 list_for_each_entry(entry, &syscon_list, list)
177 if (entry->np == np) {
178 syscon = entry;
179 break;
180 }
181
182 if (!syscon) {
183 if (create_regmap)
184 syscon = of_syscon_register(np, check_res);
185 else
186 syscon = ERR_PTR(-EPROBE_DEFER);
187 }
188 mutex_unlock(&syscon_list_lock);
189
190 if (IS_ERR(syscon))
191 return ERR_CAST(syscon);
192
193 return syscon->regmap;
194}
195
196/**
197 * of_syscon_register_regmap() - Register regmap for specified device node
198 * @np: Device tree node
199 * @regmap: Pointer to regmap object
200 *
201 * Register an externally created regmap object with syscon for the specified
202 * device tree node. This regmap will then be returned to client drivers using
203 * the syscon_regmap_lookup_by_phandle() API.
204 *
205 * Return: 0 on success, negative error code on failure.
206 */
207int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap)
208{
209 struct syscon *entry, *syscon = NULL;
210 int ret;
211
212 if (!np || !regmap)
213 return -EINVAL;
214
215 syscon = kzalloc_obj(*syscon);
216 if (!syscon)
217 return -ENOMEM;
218
219 /* check if syscon entry already exists */
220 mutex_lock(&syscon_list_lock);
221
222 list_for_each_entry(entry, &syscon_list, list)
223 if (entry->np == np) {
224 ret = -EEXIST;
225 goto err_unlock;
226 }
227
228 syscon->regmap = regmap;
229 syscon->np = np;
230
231 /* register the regmap in syscon list */
232 list_add_tail(&syscon->list, &syscon_list);
233 mutex_unlock(&syscon_list_lock);
234
235 return 0;
236
237err_unlock:
238 mutex_unlock(&syscon_list_lock);
239 kfree(syscon);
240 return ret;
241}
242EXPORT_SYMBOL_GPL(of_syscon_register_regmap);
243
244/**
245 * device_node_to_regmap() - Get or create a regmap for specified device node
246 * @np: Device tree node
247 *
248 * Get a regmap for the specified device node. If there's not an existing
249 * regmap, then one is instantiated. This function should not be used if the
250 * device node has a custom regmap driver or has resources (clocks, resets) to
251 * be managed. Use syscon_node_to_regmap() instead for those cases.
252 *
253 * Return: regmap ptr on success, negative error code on failure.
254 */
255struct regmap *device_node_to_regmap(struct device_node *np)
256{
257 return device_node_get_regmap(np, true, false);
258}
259EXPORT_SYMBOL_GPL(device_node_to_regmap);
260
261/**
262 * syscon_node_to_regmap() - Get or create a regmap for specified syscon device node
263 * @np: Device tree node
264 *
265 * Get a regmap for the specified device node. If there's not an existing
266 * regmap, then one is instantiated if the node is a generic "syscon". This
267 * function is safe to use for a syscon registered with
268 * of_syscon_register_regmap().
269 *
270 * Return: regmap ptr on success, negative error code on failure.
271 */
272struct regmap *syscon_node_to_regmap(struct device_node *np)
273{
274 return device_node_get_regmap(np, of_device_is_compatible(np, "syscon"), true);
275}
276EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
277
278struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
279{
280 struct device_node *syscon_np;
281 struct regmap *regmap;
282
283 syscon_np = of_find_compatible_node(NULL, NULL, s);
284 if (!syscon_np)
285 return ERR_PTR(-ENODEV);
286
287 regmap = syscon_node_to_regmap(syscon_np);
288 of_node_put(syscon_np);
289
290 return regmap;
291}
292EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
293
294struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
295 const char *property)
296{
297 struct device_node *syscon_np;
298 struct regmap *regmap;
299
300 if (property)
301 syscon_np = of_parse_phandle(np, property, 0);
302 else
303 syscon_np = np;
304
305 if (!syscon_np)
306 return ERR_PTR(-ENODEV);
307
308 regmap = syscon_node_to_regmap(syscon_np);
309
310 if (property)
311 of_node_put(syscon_np);
312
313 return regmap;
314}
315EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
316
317struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
318 const char *property,
319 int arg_count,
320 unsigned int *out_args)
321{
322 struct device_node *syscon_np;
323 struct of_phandle_args args;
324 struct regmap *regmap;
325 unsigned int index;
326 int rc;
327
328 rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
329 0, &args);
330 if (rc)
331 return ERR_PTR(rc);
332
333 syscon_np = args.np;
334 if (!syscon_np)
335 return ERR_PTR(-ENODEV);
336
337 regmap = syscon_node_to_regmap(syscon_np);
338 for (index = 0; index < arg_count; index++)
339 out_args[index] = args.args[index];
340 of_node_put(syscon_np);
341
342 return regmap;
343}
344EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
345
346/*
347 * It behaves the same as syscon_regmap_lookup_by_phandle() except where
348 * there is no regmap phandle. In this case, instead of returning -ENODEV,
349 * the function returns NULL.
350 */
351struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
352 const char *property)
353{
354 struct regmap *regmap;
355
356 regmap = syscon_regmap_lookup_by_phandle(np, property);
357 if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
358 return NULL;
359
360 return regmap;
361}
362EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);