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1 | /* |
2 | * Register map access API | |
3 | * | |
4 | * Copyright 2011 Wolfson Microelectronics plc | |
5 | * | |
6 | * Author: Mark Brown <broonie@opensource.wolfsonmicro.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/slab.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/mutex.h> | |
16 | #include <linux/err.h> | |
17 | ||
18 | #include <linux/regmap.h> | |
19 | ||
20 | struct regmap; | |
21 | ||
22 | struct regmap_format { | |
23 | size_t buf_size; | |
24 | size_t reg_bytes; | |
25 | size_t val_bytes; | |
26 | void (*format_write)(struct regmap *map, | |
27 | unsigned int reg, unsigned int val); | |
28 | void (*format_reg)(void *buf, unsigned int reg); | |
29 | void (*format_val)(void *buf, unsigned int val); | |
30 | unsigned int (*parse_val)(void *buf); | |
31 | }; | |
32 | ||
33 | struct regmap { | |
34 | struct mutex lock; | |
35 | ||
36 | struct device *dev; /* Device we do I/O on */ | |
37 | void *work_buf; /* Scratch buffer used to format I/O */ | |
38 | struct regmap_format format; /* Buffer format */ | |
39 | const struct regmap_bus *bus; | |
40 | }; | |
41 | ||
42 | static void regmap_format_4_12_write(struct regmap *map, | |
43 | unsigned int reg, unsigned int val) | |
44 | { | |
45 | __be16 *out = map->work_buf; | |
46 | *out = cpu_to_be16((reg << 12) | val); | |
47 | } | |
48 | ||
49 | static void regmap_format_7_9_write(struct regmap *map, | |
50 | unsigned int reg, unsigned int val) | |
51 | { | |
52 | __be16 *out = map->work_buf; | |
53 | *out = cpu_to_be16((reg << 9) | val); | |
54 | } | |
55 | ||
56 | static void regmap_format_8(void *buf, unsigned int val) | |
57 | { | |
58 | u8 *b = buf; | |
59 | ||
60 | b[0] = val; | |
61 | } | |
62 | ||
63 | static void regmap_format_16(void *buf, unsigned int val) | |
64 | { | |
65 | __be16 *b = buf; | |
66 | ||
67 | b[0] = cpu_to_be16(val); | |
68 | } | |
69 | ||
70 | static unsigned int regmap_parse_8(void *buf) | |
71 | { | |
72 | u8 *b = buf; | |
73 | ||
74 | return b[0]; | |
75 | } | |
76 | ||
77 | static unsigned int regmap_parse_16(void *buf) | |
78 | { | |
79 | __be16 *b = buf; | |
80 | ||
81 | b[0] = be16_to_cpu(b[0]); | |
82 | ||
83 | return b[0]; | |
84 | } | |
85 | ||
86 | /** | |
87 | * regmap_init(): Initialise register map | |
88 | * | |
89 | * @dev: Device that will be interacted with | |
90 | * @bus: Bus-specific callbacks to use with device | |
91 | * @config: Configuration for register map | |
92 | * | |
93 | * The return value will be an ERR_PTR() on error or a valid pointer to | |
94 | * a struct regmap. This function should generally not be called | |
95 | * directly, it should be called by bus-specific init functions. | |
96 | */ | |
97 | struct regmap *regmap_init(struct device *dev, | |
98 | const struct regmap_bus *bus, | |
99 | const struct regmap_config *config) | |
100 | { | |
101 | struct regmap *map; | |
102 | int ret = -EINVAL; | |
103 | ||
104 | if (!bus || !config) | |
105 | return NULL; | |
106 | ||
107 | map = kzalloc(sizeof(*map), GFP_KERNEL); | |
108 | if (map == NULL) { | |
109 | ret = -ENOMEM; | |
110 | goto err; | |
111 | } | |
112 | ||
113 | mutex_init(&map->lock); | |
114 | map->format.buf_size = (config->reg_bits + config->val_bits) / 8; | |
115 | map->format.reg_bytes = config->reg_bits / 8; | |
116 | map->format.val_bytes = config->val_bits / 8; | |
117 | map->dev = dev; | |
118 | map->bus = bus; | |
119 | ||
120 | switch (config->reg_bits) { | |
121 | case 4: | |
122 | switch (config->val_bits) { | |
123 | case 12: | |
124 | map->format.format_write = regmap_format_4_12_write; | |
125 | break; | |
126 | default: | |
127 | goto err_map; | |
128 | } | |
129 | break; | |
130 | ||
131 | case 7: | |
132 | switch (config->val_bits) { | |
133 | case 9: | |
134 | map->format.format_write = regmap_format_7_9_write; | |
135 | break; | |
136 | default: | |
137 | goto err_map; | |
138 | } | |
139 | break; | |
140 | ||
141 | case 8: | |
142 | map->format.format_reg = regmap_format_8; | |
143 | break; | |
144 | ||
145 | case 16: | |
146 | map->format.format_reg = regmap_format_16; | |
147 | break; | |
148 | ||
149 | default: | |
150 | goto err_map; | |
151 | } | |
152 | ||
153 | switch (config->val_bits) { | |
154 | case 8: | |
155 | map->format.format_val = regmap_format_8; | |
156 | map->format.parse_val = regmap_parse_8; | |
157 | break; | |
158 | case 16: | |
159 | map->format.format_val = regmap_format_16; | |
160 | map->format.parse_val = regmap_parse_16; | |
161 | break; | |
162 | } | |
163 | ||
164 | if (!map->format.format_write && | |
165 | !(map->format.format_reg && map->format.format_val)) | |
166 | goto err_map; | |
167 | ||
168 | map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL); | |
169 | if (map->work_buf == NULL) { | |
170 | ret = -ENOMEM; | |
171 | goto err_bus; | |
172 | } | |
173 | ||
174 | return map; | |
175 | ||
176 | err_bus: | |
177 | module_put(map->bus->owner); | |
178 | err_map: | |
179 | kfree(map); | |
180 | err: | |
181 | return ERR_PTR(ret); | |
182 | } | |
183 | EXPORT_SYMBOL_GPL(regmap_init); | |
184 | ||
185 | /** | |
186 | * regmap_exit(): Free a previously allocated register map | |
187 | */ | |
188 | void regmap_exit(struct regmap *map) | |
189 | { | |
190 | kfree(map->work_buf); | |
191 | module_put(map->bus->owner); | |
192 | kfree(map); | |
193 | } | |
194 | EXPORT_SYMBOL_GPL(regmap_exit); | |
195 | ||
196 | static int _regmap_raw_write(struct regmap *map, unsigned int reg, | |
197 | const void *val, size_t val_len) | |
198 | { | |
199 | void *buf; | |
200 | int ret = -ENOTSUPP; | |
201 | size_t len; | |
202 | ||
203 | map->format.format_reg(map->work_buf, reg); | |
204 | ||
205 | /* Try to do a gather write if we can */ | |
206 | if (map->bus->gather_write) | |
207 | ret = map->bus->gather_write(map->dev, map->work_buf, | |
208 | map->format.reg_bytes, | |
209 | val, val_len); | |
210 | ||
211 | /* Otherwise fall back on linearising by hand. */ | |
212 | if (ret == -ENOTSUPP) { | |
213 | len = map->format.reg_bytes + val_len; | |
214 | buf = kmalloc(len, GFP_KERNEL); | |
215 | if (!buf) | |
216 | return -ENOMEM; | |
217 | ||
218 | memcpy(buf, map->work_buf, map->format.reg_bytes); | |
219 | memcpy(buf + map->format.reg_bytes, val, val_len); | |
220 | ret = map->bus->write(map->dev, buf, len); | |
221 | ||
222 | kfree(buf); | |
223 | } | |
224 | ||
225 | return ret; | |
226 | } | |
227 | ||
228 | static int _regmap_write(struct regmap *map, unsigned int reg, | |
229 | unsigned int val) | |
230 | { | |
231 | BUG_ON(!map->format.format_write && !map->format.format_val); | |
232 | ||
233 | if (map->format.format_write) { | |
234 | map->format.format_write(map, reg, val); | |
235 | ||
236 | return map->bus->write(map->dev, map->work_buf, | |
237 | map->format.buf_size); | |
238 | } else { | |
239 | map->format.format_val(map->work_buf + map->format.reg_bytes, | |
240 | val); | |
241 | return _regmap_raw_write(map, reg, | |
242 | map->work_buf + map->format.reg_bytes, | |
243 | map->format.val_bytes); | |
244 | } | |
245 | } | |
246 | ||
247 | /** | |
248 | * regmap_write(): Write a value to a single register | |
249 | * | |
250 | * @map: Register map to write to | |
251 | * @reg: Register to write to | |
252 | * @val: Value to be written | |
253 | * | |
254 | * A value of zero will be returned on success, a negative errno will | |
255 | * be returned in error cases. | |
256 | */ | |
257 | int regmap_write(struct regmap *map, unsigned int reg, unsigned int val) | |
258 | { | |
259 | int ret; | |
260 | ||
261 | mutex_lock(&map->lock); | |
262 | ||
263 | ret = _regmap_write(map, reg, val); | |
264 | ||
265 | mutex_unlock(&map->lock); | |
266 | ||
267 | return ret; | |
268 | } | |
269 | EXPORT_SYMBOL_GPL(regmap_write); | |
270 | ||
271 | /** | |
272 | * regmap_raw_write(): Write raw values to one or more registers | |
273 | * | |
274 | * @map: Register map to write to | |
275 | * @reg: Initial register to write to | |
276 | * @val: Block of data to be written, laid out for direct transmission to the | |
277 | * device | |
278 | * @val_len: Length of data pointed to by val. | |
279 | * | |
280 | * This function is intended to be used for things like firmware | |
281 | * download where a large block of data needs to be transferred to the | |
282 | * device. No formatting will be done on the data provided. | |
283 | * | |
284 | * A value of zero will be returned on success, a negative errno will | |
285 | * be returned in error cases. | |
286 | */ | |
287 | int regmap_raw_write(struct regmap *map, unsigned int reg, | |
288 | const void *val, size_t val_len) | |
289 | { | |
290 | int ret; | |
291 | ||
292 | mutex_lock(&map->lock); | |
293 | ||
294 | ret = _regmap_raw_write(map, reg, val, val_len); | |
295 | ||
296 | mutex_unlock(&map->lock); | |
297 | ||
298 | return ret; | |
299 | } | |
300 | EXPORT_SYMBOL_GPL(regmap_raw_write); | |
301 | ||
302 | static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val, | |
303 | unsigned int val_len) | |
304 | { | |
305 | u8 *u8 = map->work_buf; | |
306 | int ret; | |
307 | ||
308 | map->format.format_reg(map->work_buf, reg); | |
309 | ||
310 | /* | |
311 | * Some buses flag reads by setting the high bits in the | |
312 | * register addresss; since it's always the high bits for all | |
313 | * current formats we can do this here rather than in | |
314 | * formatting. This may break if we get interesting formats. | |
315 | */ | |
316 | if (map->bus->read_flag_mask) | |
317 | u8[0] |= map->bus->read_flag_mask; | |
318 | ||
319 | ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes, | |
320 | val, map->format.val_bytes); | |
321 | if (ret != 0) | |
322 | return ret; | |
323 | ||
324 | return 0; | |
325 | } | |
326 | ||
327 | static int _regmap_read(struct regmap *map, unsigned int reg, | |
328 | unsigned int *val) | |
329 | { | |
330 | int ret; | |
331 | ||
332 | if (!map->format.parse_val) | |
333 | return -EINVAL; | |
334 | ||
335 | ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes); | |
336 | if (ret == 0) | |
337 | *val = map->format.parse_val(map->work_buf); | |
338 | ||
339 | return ret; | |
340 | } | |
341 | ||
342 | /** | |
343 | * regmap_read(): Read a value from a single register | |
344 | * | |
345 | * @map: Register map to write to | |
346 | * @reg: Register to be read from | |
347 | * @val: Pointer to store read value | |
348 | * | |
349 | * A value of zero will be returned on success, a negative errno will | |
350 | * be returned in error cases. | |
351 | */ | |
352 | int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val) | |
353 | { | |
354 | int ret; | |
355 | ||
356 | mutex_lock(&map->lock); | |
357 | ||
358 | ret = _regmap_read(map, reg, val); | |
359 | ||
360 | mutex_unlock(&map->lock); | |
361 | ||
362 | return ret; | |
363 | } | |
364 | EXPORT_SYMBOL_GPL(regmap_read); | |
365 | ||
366 | /** | |
367 | * regmap_raw_read(): Read raw data from the device | |
368 | * | |
369 | * @map: Register map to write to | |
370 | * @reg: First register to be read from | |
371 | * @val: Pointer to store read value | |
372 | * @val_len: Size of data to read | |
373 | * | |
374 | * A value of zero will be returned on success, a negative errno will | |
375 | * be returned in error cases. | |
376 | */ | |
377 | int regmap_raw_read(struct regmap *map, unsigned int reg, void *val, | |
378 | size_t val_len) | |
379 | { | |
380 | int ret; | |
381 | ||
382 | mutex_lock(&map->lock); | |
383 | ||
384 | ret = _regmap_raw_read(map, reg, val, val_len); | |
385 | ||
386 | mutex_unlock(&map->lock); | |
387 | ||
388 | return ret; | |
389 | } | |
390 | EXPORT_SYMBOL_GPL(regmap_raw_read); | |
391 | ||
392 | /** | |
393 | * regmap_bulk_read(): Read multiple registers from the device | |
394 | * | |
395 | * @map: Register map to write to | |
396 | * @reg: First register to be read from | |
397 | * @val: Pointer to store read value, in native register size for device | |
398 | * @val_count: Number of registers to read | |
399 | * | |
400 | * A value of zero will be returned on success, a negative errno will | |
401 | * be returned in error cases. | |
402 | */ | |
403 | int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val, | |
404 | size_t val_count) | |
405 | { | |
406 | int ret, i; | |
407 | size_t val_bytes = map->format.val_bytes; | |
408 | ||
409 | if (!map->format.parse_val) | |
410 | return -EINVAL; | |
411 | ||
412 | ret = regmap_raw_read(map, reg, val, val_bytes * val_count); | |
413 | if (ret != 0) | |
414 | return ret; | |
415 | ||
416 | for (i = 0; i < val_count * val_bytes; i += val_bytes) | |
417 | map->format.parse_val(val + i); | |
418 | ||
419 | return 0; | |
420 | } | |
421 | EXPORT_SYMBOL_GPL(regmap_bulk_read); | |
422 | ||
423 | /** | |
424 | * remap_update_bits: Perform a read/modify/write cycle on the register map | |
425 | * | |
426 | * @map: Register map to update | |
427 | * @reg: Register to update | |
428 | * @mask: Bitmask to change | |
429 | * @val: New value for bitmask | |
430 | * | |
431 | * Returns zero for success, a negative number on error. | |
432 | */ | |
433 | int regmap_update_bits(struct regmap *map, unsigned int reg, | |
434 | unsigned int mask, unsigned int val) | |
435 | { | |
436 | int ret; | |
437 | unsigned int tmp; | |
438 | ||
439 | mutex_lock(&map->lock); | |
440 | ||
441 | ret = _regmap_read(map, reg, &tmp); | |
442 | if (ret != 0) | |
443 | goto out; | |
444 | ||
445 | tmp &= ~mask; | |
446 | tmp |= val & mask; | |
447 | ||
448 | ret = _regmap_write(map, reg, tmp); | |
449 | ||
450 | out: | |
451 | mutex_unlock(&map->lock); | |
452 | ||
453 | return ret; | |
454 | } | |
455 | EXPORT_SYMBOL_GPL(regmap_update_bits); |