regmap: Implement writable register checks
[deliverable/linux.git] / drivers / base / regmap / regmap.c
CommitLineData
b83a313b
MB
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
fb2736bb
MB
20#define CREATE_TRACE_POINTS
21#include <trace/events/regmap.h>
22
b83a313b
MB
23struct regmap;
24
25struct regmap_format {
26 size_t buf_size;
27 size_t reg_bytes;
28 size_t val_bytes;
29 void (*format_write)(struct regmap *map,
30 unsigned int reg, unsigned int val);
31 void (*format_reg)(void *buf, unsigned int reg);
32 void (*format_val)(void *buf, unsigned int val);
33 unsigned int (*parse_val)(void *buf);
34};
35
36struct regmap {
37 struct mutex lock;
38
39 struct device *dev; /* Device we do I/O on */
40 void *work_buf; /* Scratch buffer used to format I/O */
41 struct regmap_format format; /* Buffer format */
42 const struct regmap_bus *bus;
2e2ae66d
MB
43
44 unsigned int max_register;
45 bool (*writeable_reg)(struct device *dev, unsigned int reg);
46 bool (*readable_reg)(struct device *dev, unsigned int reg);
47 bool (*volatile_reg)(struct device *dev, unsigned int reg);
b83a313b
MB
48};
49
50static void regmap_format_4_12_write(struct regmap *map,
51 unsigned int reg, unsigned int val)
52{
53 __be16 *out = map->work_buf;
54 *out = cpu_to_be16((reg << 12) | val);
55}
56
57static void regmap_format_7_9_write(struct regmap *map,
58 unsigned int reg, unsigned int val)
59{
60 __be16 *out = map->work_buf;
61 *out = cpu_to_be16((reg << 9) | val);
62}
63
64static void regmap_format_8(void *buf, unsigned int val)
65{
66 u8 *b = buf;
67
68 b[0] = val;
69}
70
71static void regmap_format_16(void *buf, unsigned int val)
72{
73 __be16 *b = buf;
74
75 b[0] = cpu_to_be16(val);
76}
77
78static unsigned int regmap_parse_8(void *buf)
79{
80 u8 *b = buf;
81
82 return b[0];
83}
84
85static unsigned int regmap_parse_16(void *buf)
86{
87 __be16 *b = buf;
88
89 b[0] = be16_to_cpu(b[0]);
90
91 return b[0];
92}
93
94/**
95 * regmap_init(): Initialise register map
96 *
97 * @dev: Device that will be interacted with
98 * @bus: Bus-specific callbacks to use with device
99 * @config: Configuration for register map
100 *
101 * The return value will be an ERR_PTR() on error or a valid pointer to
102 * a struct regmap. This function should generally not be called
103 * directly, it should be called by bus-specific init functions.
104 */
105struct regmap *regmap_init(struct device *dev,
106 const struct regmap_bus *bus,
107 const struct regmap_config *config)
108{
109 struct regmap *map;
110 int ret = -EINVAL;
111
112 if (!bus || !config)
113 return NULL;
114
115 map = kzalloc(sizeof(*map), GFP_KERNEL);
116 if (map == NULL) {
117 ret = -ENOMEM;
118 goto err;
119 }
120
121 mutex_init(&map->lock);
122 map->format.buf_size = (config->reg_bits + config->val_bits) / 8;
123 map->format.reg_bytes = config->reg_bits / 8;
124 map->format.val_bytes = config->val_bits / 8;
125 map->dev = dev;
126 map->bus = bus;
2e2ae66d
MB
127 map->max_register = config->max_register;
128 map->writeable_reg = config->writeable_reg;
129 map->readable_reg = config->readable_reg;
130 map->volatile_reg = config->volatile_reg;
b83a313b
MB
131
132 switch (config->reg_bits) {
133 case 4:
134 switch (config->val_bits) {
135 case 12:
136 map->format.format_write = regmap_format_4_12_write;
137 break;
138 default:
139 goto err_map;
140 }
141 break;
142
143 case 7:
144 switch (config->val_bits) {
145 case 9:
146 map->format.format_write = regmap_format_7_9_write;
147 break;
148 default:
149 goto err_map;
150 }
151 break;
152
153 case 8:
154 map->format.format_reg = regmap_format_8;
155 break;
156
157 case 16:
158 map->format.format_reg = regmap_format_16;
159 break;
160
161 default:
162 goto err_map;
163 }
164
165 switch (config->val_bits) {
166 case 8:
167 map->format.format_val = regmap_format_8;
168 map->format.parse_val = regmap_parse_8;
169 break;
170 case 16:
171 map->format.format_val = regmap_format_16;
172 map->format.parse_val = regmap_parse_16;
173 break;
174 }
175
176 if (!map->format.format_write &&
177 !(map->format.format_reg && map->format.format_val))
178 goto err_map;
179
180 map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL);
181 if (map->work_buf == NULL) {
182 ret = -ENOMEM;
183 goto err_bus;
184 }
185
186 return map;
187
188err_bus:
189 module_put(map->bus->owner);
190err_map:
191 kfree(map);
192err:
193 return ERR_PTR(ret);
194}
195EXPORT_SYMBOL_GPL(regmap_init);
196
197/**
198 * regmap_exit(): Free a previously allocated register map
199 */
200void regmap_exit(struct regmap *map)
201{
202 kfree(map->work_buf);
203 module_put(map->bus->owner);
204 kfree(map);
205}
206EXPORT_SYMBOL_GPL(regmap_exit);
207
208static int _regmap_raw_write(struct regmap *map, unsigned int reg,
209 const void *val, size_t val_len)
210{
211 void *buf;
212 int ret = -ENOTSUPP;
213 size_t len;
73304781
MB
214 int i;
215
216 /* Check for unwritable registers before we start */
217 if (map->writeable_reg)
218 for (i = 0; i < val_len / map->format.val_bytes; i++)
219 if (!map->writeable_reg(map->dev, reg + i))
220 return -EINVAL;
b83a313b
MB
221
222 map->format.format_reg(map->work_buf, reg);
223
fb2736bb
MB
224 trace_regmap_hw_write_start(map->dev, reg,
225 val_len / map->format.val_bytes);
226
2547e201
MB
227 /* If we're doing a single register write we can probably just
228 * send the work_buf directly, otherwise try to do a gather
229 * write.
230 */
231 if (val == map->work_buf + map->format.reg_bytes)
232 ret = map->bus->write(map->dev, map->work_buf,
233 map->format.reg_bytes + val_len);
234 else if (map->bus->gather_write)
b83a313b
MB
235 ret = map->bus->gather_write(map->dev, map->work_buf,
236 map->format.reg_bytes,
237 val, val_len);
238
2547e201 239 /* If that didn't work fall back on linearising by hand. */
b83a313b
MB
240 if (ret == -ENOTSUPP) {
241 len = map->format.reg_bytes + val_len;
242 buf = kmalloc(len, GFP_KERNEL);
243 if (!buf)
244 return -ENOMEM;
245
246 memcpy(buf, map->work_buf, map->format.reg_bytes);
247 memcpy(buf + map->format.reg_bytes, val, val_len);
248 ret = map->bus->write(map->dev, buf, len);
249
250 kfree(buf);
251 }
252
fb2736bb
MB
253 trace_regmap_hw_write_done(map->dev, reg,
254 val_len / map->format.val_bytes);
255
b83a313b
MB
256 return ret;
257}
258
259static int _regmap_write(struct regmap *map, unsigned int reg,
260 unsigned int val)
261{
fb2736bb 262 int ret;
b83a313b
MB
263 BUG_ON(!map->format.format_write && !map->format.format_val);
264
fb2736bb
MB
265 trace_regmap_reg_write(map->dev, reg, val);
266
b83a313b
MB
267 if (map->format.format_write) {
268 map->format.format_write(map, reg, val);
269
fb2736bb
MB
270 trace_regmap_hw_write_start(map->dev, reg, 1);
271
272 ret = map->bus->write(map->dev, map->work_buf,
273 map->format.buf_size);
274
275 trace_regmap_hw_write_done(map->dev, reg, 1);
276
277 return ret;
b83a313b
MB
278 } else {
279 map->format.format_val(map->work_buf + map->format.reg_bytes,
280 val);
281 return _regmap_raw_write(map, reg,
282 map->work_buf + map->format.reg_bytes,
283 map->format.val_bytes);
284 }
285}
286
287/**
288 * regmap_write(): Write a value to a single register
289 *
290 * @map: Register map to write to
291 * @reg: Register to write to
292 * @val: Value to be written
293 *
294 * A value of zero will be returned on success, a negative errno will
295 * be returned in error cases.
296 */
297int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
298{
299 int ret;
300
301 mutex_lock(&map->lock);
302
303 ret = _regmap_write(map, reg, val);
304
305 mutex_unlock(&map->lock);
306
307 return ret;
308}
309EXPORT_SYMBOL_GPL(regmap_write);
310
311/**
312 * regmap_raw_write(): Write raw values to one or more registers
313 *
314 * @map: Register map to write to
315 * @reg: Initial register to write to
316 * @val: Block of data to be written, laid out for direct transmission to the
317 * device
318 * @val_len: Length of data pointed to by val.
319 *
320 * This function is intended to be used for things like firmware
321 * download where a large block of data needs to be transferred to the
322 * device. No formatting will be done on the data provided.
323 *
324 * A value of zero will be returned on success, a negative errno will
325 * be returned in error cases.
326 */
327int regmap_raw_write(struct regmap *map, unsigned int reg,
328 const void *val, size_t val_len)
329{
330 int ret;
331
332 mutex_lock(&map->lock);
333
334 ret = _regmap_raw_write(map, reg, val, val_len);
335
336 mutex_unlock(&map->lock);
337
338 return ret;
339}
340EXPORT_SYMBOL_GPL(regmap_raw_write);
341
342static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
343 unsigned int val_len)
344{
345 u8 *u8 = map->work_buf;
346 int ret;
347
348 map->format.format_reg(map->work_buf, reg);
349
350 /*
351 * Some buses flag reads by setting the high bits in the
352 * register addresss; since it's always the high bits for all
353 * current formats we can do this here rather than in
354 * formatting. This may break if we get interesting formats.
355 */
356 if (map->bus->read_flag_mask)
357 u8[0] |= map->bus->read_flag_mask;
358
fb2736bb
MB
359 trace_regmap_hw_read_start(map->dev, reg,
360 val_len / map->format.val_bytes);
361
b83a313b 362 ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes,
40c5cc26 363 val, val_len);
b83a313b 364
fb2736bb
MB
365 trace_regmap_hw_read_done(map->dev, reg,
366 val_len / map->format.val_bytes);
367
368 return ret;
b83a313b
MB
369}
370
371static int _regmap_read(struct regmap *map, unsigned int reg,
372 unsigned int *val)
373{
374 int ret;
375
376 if (!map->format.parse_val)
377 return -EINVAL;
378
379 ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
fb2736bb 380 if (ret == 0) {
b83a313b 381 *val = map->format.parse_val(map->work_buf);
fb2736bb
MB
382 trace_regmap_reg_read(map->dev, reg, *val);
383 }
b83a313b
MB
384
385 return ret;
386}
387
388/**
389 * regmap_read(): Read a value from a single register
390 *
391 * @map: Register map to write to
392 * @reg: Register to be read from
393 * @val: Pointer to store read value
394 *
395 * A value of zero will be returned on success, a negative errno will
396 * be returned in error cases.
397 */
398int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
399{
400 int ret;
401
402 mutex_lock(&map->lock);
403
404 ret = _regmap_read(map, reg, val);
405
406 mutex_unlock(&map->lock);
407
408 return ret;
409}
410EXPORT_SYMBOL_GPL(regmap_read);
411
412/**
413 * regmap_raw_read(): Read raw data from the device
414 *
415 * @map: Register map to write to
416 * @reg: First register to be read from
417 * @val: Pointer to store read value
418 * @val_len: Size of data to read
419 *
420 * A value of zero will be returned on success, a negative errno will
421 * be returned in error cases.
422 */
423int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
424 size_t val_len)
425{
426 int ret;
427
428 mutex_lock(&map->lock);
429
430 ret = _regmap_raw_read(map, reg, val, val_len);
431
432 mutex_unlock(&map->lock);
433
434 return ret;
435}
436EXPORT_SYMBOL_GPL(regmap_raw_read);
437
438/**
439 * regmap_bulk_read(): Read multiple registers from the device
440 *
441 * @map: Register map to write to
442 * @reg: First register to be read from
443 * @val: Pointer to store read value, in native register size for device
444 * @val_count: Number of registers to read
445 *
446 * A value of zero will be returned on success, a negative errno will
447 * be returned in error cases.
448 */
449int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
450 size_t val_count)
451{
452 int ret, i;
453 size_t val_bytes = map->format.val_bytes;
454
455 if (!map->format.parse_val)
456 return -EINVAL;
457
458 ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
459 if (ret != 0)
460 return ret;
461
462 for (i = 0; i < val_count * val_bytes; i += val_bytes)
463 map->format.parse_val(val + i);
464
465 return 0;
466}
467EXPORT_SYMBOL_GPL(regmap_bulk_read);
468
469/**
470 * remap_update_bits: Perform a read/modify/write cycle on the register map
471 *
472 * @map: Register map to update
473 * @reg: Register to update
474 * @mask: Bitmask to change
475 * @val: New value for bitmask
476 *
477 * Returns zero for success, a negative number on error.
478 */
479int regmap_update_bits(struct regmap *map, unsigned int reg,
480 unsigned int mask, unsigned int val)
481{
482 int ret;
483 unsigned int tmp;
484
485 mutex_lock(&map->lock);
486
487 ret = _regmap_read(map, reg, &tmp);
488 if (ret != 0)
489 goto out;
490
491 tmp &= ~mask;
492 tmp |= val & mask;
493
494 ret = _regmap_write(map, reg, tmp);
495
496out:
497 mutex_unlock(&map->lock);
498
499 return ret;
500}
501EXPORT_SYMBOL_GPL(regmap_update_bits);
This page took 0.05277 seconds and 5 git commands to generate.