1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Register map access API - I2C support
4 //
5 // Copyright 2011 Wolfson Microelectronics plc
6 //
7 // Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
8
9 #include <linux/regmap.h>
10 #include <linux/i2c.h>
11 #include <linux/module.h>
12
13 #include "internal.h"
14
regmap_smbus_byte_reg_read(void * context,unsigned int reg,unsigned int * val)15 static int regmap_smbus_byte_reg_read(void *context, unsigned int reg,
16 unsigned int *val)
17 {
18 struct device *dev = context;
19 struct i2c_client *i2c = to_i2c_client(dev);
20 int ret;
21
22 if (reg > 0xff)
23 return -EINVAL;
24
25 ret = i2c_smbus_read_byte_data(i2c, reg);
26 if (ret < 0)
27 return ret;
28
29 *val = ret;
30
31 return 0;
32 }
33
regmap_smbus_byte_reg_write(void * context,unsigned int reg,unsigned int val)34 static int regmap_smbus_byte_reg_write(void *context, unsigned int reg,
35 unsigned int val)
36 {
37 struct device *dev = context;
38 struct i2c_client *i2c = to_i2c_client(dev);
39
40 if (val > 0xff || reg > 0xff)
41 return -EINVAL;
42
43 return i2c_smbus_write_byte_data(i2c, reg, val);
44 }
45
46 static const struct regmap_bus regmap_smbus_byte = {
47 .reg_write = regmap_smbus_byte_reg_write,
48 .reg_read = regmap_smbus_byte_reg_read,
49 };
50
regmap_smbus_word_reg_read(void * context,unsigned int reg,unsigned int * val)51 static int regmap_smbus_word_reg_read(void *context, unsigned int reg,
52 unsigned int *val)
53 {
54 struct device *dev = context;
55 struct i2c_client *i2c = to_i2c_client(dev);
56 int ret;
57
58 if (reg > 0xff)
59 return -EINVAL;
60
61 ret = i2c_smbus_read_word_data(i2c, reg);
62 if (ret < 0)
63 return ret;
64
65 *val = ret;
66
67 return 0;
68 }
69
regmap_smbus_word_reg_write(void * context,unsigned int reg,unsigned int val)70 static int regmap_smbus_word_reg_write(void *context, unsigned int reg,
71 unsigned int val)
72 {
73 struct device *dev = context;
74 struct i2c_client *i2c = to_i2c_client(dev);
75
76 if (val > 0xffff || reg > 0xff)
77 return -EINVAL;
78
79 return i2c_smbus_write_word_data(i2c, reg, val);
80 }
81
82 static const struct regmap_bus regmap_smbus_word = {
83 .reg_write = regmap_smbus_word_reg_write,
84 .reg_read = regmap_smbus_word_reg_read,
85 };
86
regmap_smbus_word_read_swapped(void * context,unsigned int reg,unsigned int * val)87 static int regmap_smbus_word_read_swapped(void *context, unsigned int reg,
88 unsigned int *val)
89 {
90 struct device *dev = context;
91 struct i2c_client *i2c = to_i2c_client(dev);
92 int ret;
93
94 if (reg > 0xff)
95 return -EINVAL;
96
97 ret = i2c_smbus_read_word_swapped(i2c, reg);
98 if (ret < 0)
99 return ret;
100
101 *val = ret;
102
103 return 0;
104 }
105
regmap_smbus_word_write_swapped(void * context,unsigned int reg,unsigned int val)106 static int regmap_smbus_word_write_swapped(void *context, unsigned int reg,
107 unsigned int val)
108 {
109 struct device *dev = context;
110 struct i2c_client *i2c = to_i2c_client(dev);
111
112 if (val > 0xffff || reg > 0xff)
113 return -EINVAL;
114
115 return i2c_smbus_write_word_swapped(i2c, reg, val);
116 }
117
118 static const struct regmap_bus regmap_smbus_word_swapped = {
119 .reg_write = regmap_smbus_word_write_swapped,
120 .reg_read = regmap_smbus_word_read_swapped,
121 };
122
regmap_i2c_write(void * context,const void * data,size_t count)123 static int regmap_i2c_write(void *context, const void *data, size_t count)
124 {
125 struct device *dev = context;
126 struct i2c_client *i2c = to_i2c_client(dev);
127 int ret;
128
129 ret = i2c_master_send(i2c, data, count);
130 if (ret == count)
131 return 0;
132 else if (ret < 0)
133 return ret;
134 else
135 return -EIO;
136 }
137
regmap_i2c_gather_write(void * context,const void * reg,size_t reg_size,const void * val,size_t val_size)138 static int regmap_i2c_gather_write(void *context,
139 const void *reg, size_t reg_size,
140 const void *val, size_t val_size)
141 {
142 struct device *dev = context;
143 struct i2c_client *i2c = to_i2c_client(dev);
144 struct i2c_msg xfer[2];
145 int ret;
146
147 /* If the I2C controller can't do a gather tell the core, it
148 * will substitute in a linear write for us.
149 */
150 if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_NOSTART))
151 return -ENOTSUPP;
152
153 xfer[0].addr = i2c->addr;
154 xfer[0].flags = 0;
155 xfer[0].len = reg_size;
156 xfer[0].buf = (void *)reg;
157
158 xfer[1].addr = i2c->addr;
159 xfer[1].flags = I2C_M_NOSTART;
160 xfer[1].len = val_size;
161 xfer[1].buf = (void *)val;
162
163 ret = i2c_transfer(i2c->adapter, xfer, 2);
164 if (ret == 2)
165 return 0;
166 if (ret < 0)
167 return ret;
168 else
169 return -EIO;
170 }
171
regmap_i2c_read(void * context,const void * reg,size_t reg_size,void * val,size_t val_size)172 static int regmap_i2c_read(void *context,
173 const void *reg, size_t reg_size,
174 void *val, size_t val_size)
175 {
176 struct device *dev = context;
177 struct i2c_client *i2c = to_i2c_client(dev);
178 struct i2c_msg xfer[2];
179 int ret;
180
181 xfer[0].addr = i2c->addr;
182 xfer[0].flags = 0;
183 xfer[0].len = reg_size;
184 xfer[0].buf = (void *)reg;
185
186 xfer[1].addr = i2c->addr;
187 xfer[1].flags = I2C_M_RD;
188 xfer[1].len = val_size;
189 xfer[1].buf = val;
190
191 ret = i2c_transfer(i2c->adapter, xfer, 2);
192 if (ret == 2)
193 return 0;
194 else if (ret < 0)
195 return ret;
196 else
197 return -EIO;
198 }
199
200 static const struct regmap_bus regmap_i2c = {
201 .write = regmap_i2c_write,
202 .gather_write = regmap_i2c_gather_write,
203 .read = regmap_i2c_read,
204 .reg_format_endian_default = REGMAP_ENDIAN_BIG,
205 .val_format_endian_default = REGMAP_ENDIAN_BIG,
206 };
207
regmap_i2c_smbus_i2c_write(void * context,const void * data,size_t count)208 static int regmap_i2c_smbus_i2c_write(void *context, const void *data,
209 size_t count)
210 {
211 struct device *dev = context;
212 struct i2c_client *i2c = to_i2c_client(dev);
213
214 if (count < 1)
215 return -EINVAL;
216
217 --count;
218 return i2c_smbus_write_i2c_block_data(i2c, ((u8 *)data)[0], count,
219 ((u8 *)data + 1));
220 }
221
regmap_i2c_smbus_i2c_read(void * context,const void * reg,size_t reg_size,void * val,size_t val_size)222 static int regmap_i2c_smbus_i2c_read(void *context, const void *reg,
223 size_t reg_size, void *val,
224 size_t val_size)
225 {
226 struct device *dev = context;
227 struct i2c_client *i2c = to_i2c_client(dev);
228 int ret;
229
230 if (reg_size != 1 || val_size < 1)
231 return -EINVAL;
232
233 ret = i2c_smbus_read_i2c_block_data(i2c, ((u8 *)reg)[0], val_size, val);
234 if (ret == val_size)
235 return 0;
236 else if (ret < 0)
237 return ret;
238 else
239 return -EIO;
240 }
241
242 static const struct regmap_bus regmap_i2c_smbus_i2c_block = {
243 .write = regmap_i2c_smbus_i2c_write,
244 .read = regmap_i2c_smbus_i2c_read,
245 .max_raw_read = I2C_SMBUS_BLOCK_MAX - 1,
246 .max_raw_write = I2C_SMBUS_BLOCK_MAX - 1,
247 };
248
regmap_i2c_smbus_i2c_write_reg16(void * context,const void * data,size_t count)249 static int regmap_i2c_smbus_i2c_write_reg16(void *context, const void *data,
250 size_t count)
251 {
252 struct device *dev = context;
253 struct i2c_client *i2c = to_i2c_client(dev);
254
255 if (count < 2)
256 return -EINVAL;
257
258 count--;
259 return i2c_smbus_write_i2c_block_data(i2c, ((u8 *)data)[0], count,
260 (u8 *)data + 1);
261 }
262
regmap_i2c_smbus_i2c_read_reg16(void * context,const void * reg,size_t reg_size,void * val,size_t val_size)263 static int regmap_i2c_smbus_i2c_read_reg16(void *context, const void *reg,
264 size_t reg_size, void *val,
265 size_t val_size)
266 {
267 struct device *dev = context;
268 struct i2c_client *i2c = to_i2c_client(dev);
269 int ret, count, len = val_size;
270
271 if (reg_size != 2)
272 return -EINVAL;
273
274 ret = i2c_smbus_write_byte_data(i2c, ((u16 *)reg)[0] & 0xff,
275 ((u16 *)reg)[0] >> 8);
276 if (ret < 0)
277 return ret;
278
279 count = 0;
280 do {
281 /* Current Address Read */
282 ret = i2c_smbus_read_byte(i2c);
283 if (ret < 0)
284 break;
285
286 *((u8 *)val++) = ret;
287 count++;
288 len--;
289 } while (len > 0);
290
291 if (count == val_size)
292 return 0;
293 else if (ret < 0)
294 return ret;
295 else
296 return -EIO;
297 }
298
299 static const struct regmap_bus regmap_i2c_smbus_i2c_block_reg16 = {
300 .write = regmap_i2c_smbus_i2c_write_reg16,
301 .read = regmap_i2c_smbus_i2c_read_reg16,
302 .max_raw_read = I2C_SMBUS_BLOCK_MAX - 2,
303 .max_raw_write = I2C_SMBUS_BLOCK_MAX - 2,
304 };
305
regmap_get_i2c_bus(struct i2c_client * i2c,const struct regmap_config * config)306 static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,
307 const struct regmap_config *config)
308 {
309 const struct i2c_adapter_quirks *quirks;
310 const struct regmap_bus *bus = NULL;
311 struct regmap_bus *ret_bus;
312 u16 max_read = 0, max_write = 0;
313
314 if (i2c_check_functionality(i2c->adapter, I2C_FUNC_I2C))
315 bus = ®map_i2c;
316 else if (config->val_bits == 8 && config->reg_bits == 8 &&
317 i2c_check_functionality(i2c->adapter,
318 I2C_FUNC_SMBUS_I2C_BLOCK))
319 bus = ®map_i2c_smbus_i2c_block;
320 else if (config->val_bits == 8 && config->reg_bits == 16 &&
321 i2c_check_functionality(i2c->adapter,
322 I2C_FUNC_SMBUS_I2C_BLOCK))
323 bus = ®map_i2c_smbus_i2c_block_reg16;
324 else if (config->val_bits == 16 && config->reg_bits == 8 &&
325 i2c_check_functionality(i2c->adapter,
326 I2C_FUNC_SMBUS_WORD_DATA))
327 switch (regmap_get_val_endian(&i2c->dev, NULL, config)) {
328 case REGMAP_ENDIAN_LITTLE:
329 bus = ®map_smbus_word;
330 break;
331 case REGMAP_ENDIAN_BIG:
332 bus = ®map_smbus_word_swapped;
333 break;
334 default: /* everything else is not supported */
335 break;
336 }
337 else if (config->val_bits == 8 && config->reg_bits == 8 &&
338 i2c_check_functionality(i2c->adapter,
339 I2C_FUNC_SMBUS_BYTE_DATA))
340 bus = ®map_smbus_byte;
341
342 if (!bus)
343 return ERR_PTR(-ENOTSUPP);
344
345 quirks = i2c->adapter->quirks;
346 if (quirks) {
347 if (quirks->max_read_len &&
348 (bus->max_raw_read == 0 || bus->max_raw_read > quirks->max_read_len))
349 max_read = quirks->max_read_len;
350
351 if (quirks->max_write_len &&
352 (bus->max_raw_write == 0 || bus->max_raw_write > quirks->max_write_len))
353 max_write = quirks->max_write_len -
354 (config->reg_bits + config->pad_bits) / BITS_PER_BYTE;
355
356 if (max_read || max_write) {
357 ret_bus = kmemdup(bus, sizeof(*bus), GFP_KERNEL);
358 if (!ret_bus)
359 return ERR_PTR(-ENOMEM);
360 ret_bus->free_on_exit = true;
361 ret_bus->max_raw_read = max_read;
362 ret_bus->max_raw_write = max_write;
363 bus = ret_bus;
364 }
365 }
366
367 return bus;
368 }
369
__regmap_init_i2c(struct i2c_client * i2c,const struct regmap_config * config,struct lock_class_key * lock_key,const char * lock_name)370 struct regmap *__regmap_init_i2c(struct i2c_client *i2c,
371 const struct regmap_config *config,
372 struct lock_class_key *lock_key,
373 const char *lock_name)
374 {
375 const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
376
377 if (IS_ERR(bus))
378 return ERR_CAST(bus);
379
380 return __regmap_init(&i2c->dev, bus, &i2c->dev, config,
381 lock_key, lock_name);
382 }
383 EXPORT_SYMBOL_GPL(__regmap_init_i2c);
384
__devm_regmap_init_i2c(struct i2c_client * i2c,const struct regmap_config * config,struct lock_class_key * lock_key,const char * lock_name)385 struct regmap *__devm_regmap_init_i2c(struct i2c_client *i2c,
386 const struct regmap_config *config,
387 struct lock_class_key *lock_key,
388 const char *lock_name)
389 {
390 const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
391
392 if (IS_ERR(bus))
393 return ERR_CAST(bus);
394
395 return __devm_regmap_init(&i2c->dev, bus, &i2c->dev, config,
396 lock_key, lock_name);
397 }
398 EXPORT_SYMBOL_GPL(__devm_regmap_init_i2c);
399
400 MODULE_DESCRIPTION("Register map access API - I2C support");
401 MODULE_LICENSE("GPL");
402