Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
22c78d1c WS |
2 | /* |
3 | * Linux I2C core SMBus and SMBus emulation code | |
4 | * | |
5 | * This file contains the SMBus functions which are always included in the I2C | |
6 | * core because they can be emulated via I2C. SMBus specific extensions | |
a23ff37b | 7 | * (e.g. smbalert) are handled in a separate i2c-smbus module. |
22c78d1c WS |
8 | * |
9 | * All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl> | |
10 | * SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and | |
11 | * Jean Delvare <jdelvare@suse.de> | |
22c78d1c WS |
12 | */ |
13 | #include <linux/device.h> | |
14 | #include <linux/err.h> | |
15 | #include <linux/i2c.h> | |
3c0a60be | 16 | #include <linux/i2c-smbus.h> |
a263a840 | 17 | #include <linux/property.h> |
8a77821e | 18 | #include <linux/slab.h> |
22c78d1c | 19 | |
83c42212 WS |
20 | #include "i2c-core.h" |
21 | ||
22c78d1c WS |
22 | #define CREATE_TRACE_POINTS |
23 | #include <trace/events/smbus.h> | |
24 | ||
25 | ||
26 | /* The SMBus parts */ | |
27 | ||
28 | #define POLY (0x1070U << 3) | |
29 | static u8 crc8(u16 data) | |
30 | { | |
31 | int i; | |
32 | ||
33 | for (i = 0; i < 8; i++) { | |
34 | if (data & 0x8000) | |
35 | data = data ^ POLY; | |
36 | data = data << 1; | |
37 | } | |
38 | return (u8)(data >> 8); | |
39 | } | |
40 | ||
87cf5127 QN |
41 | /** |
42 | * i2c_smbus_pec - Incremental CRC8 over the given input data array | |
43 | * @crc: previous return crc8 value | |
44 | * @p: pointer to data buffer. | |
45 | * @count: number of bytes in data buffer. | |
46 | * | |
47 | * Incremental CRC8 over count bytes in the array pointed to by p | |
48 | */ | |
49 | u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count) | |
22c78d1c WS |
50 | { |
51 | int i; | |
52 | ||
53 | for (i = 0; i < count; i++) | |
54 | crc = crc8((crc ^ p[i]) << 8); | |
55 | return crc; | |
56 | } | |
87cf5127 | 57 | EXPORT_SYMBOL(i2c_smbus_pec); |
22c78d1c WS |
58 | |
59 | /* Assume a 7-bit address, which is reasonable for SMBus */ | |
60 | static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg) | |
61 | { | |
62 | /* The address will be sent first */ | |
63 | u8 addr = i2c_8bit_addr_from_msg(msg); | |
64 | pec = i2c_smbus_pec(pec, &addr, 1); | |
65 | ||
66 | /* The data buffer follows */ | |
67 | return i2c_smbus_pec(pec, msg->buf, msg->len); | |
68 | } | |
69 | ||
70 | /* Used for write only transactions */ | |
71 | static inline void i2c_smbus_add_pec(struct i2c_msg *msg) | |
72 | { | |
73 | msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg); | |
74 | msg->len++; | |
75 | } | |
76 | ||
77 | /* Return <0 on CRC error | |
78 | If there was a write before this read (most cases) we need to take the | |
79 | partial CRC from the write part into account. | |
80 | Note that this function does modify the message (we need to decrease the | |
81 | message length to hide the CRC byte from the caller). */ | |
82 | static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg) | |
83 | { | |
84 | u8 rpec = msg->buf[--msg->len]; | |
85 | cpec = i2c_smbus_msg_pec(cpec, msg); | |
86 | ||
87 | if (rpec != cpec) { | |
88 | pr_debug("Bad PEC 0x%02x vs. 0x%02x\n", | |
89 | rpec, cpec); | |
90 | return -EBADMSG; | |
91 | } | |
92 | return 0; | |
93 | } | |
94 | ||
95 | /** | |
96 | * i2c_smbus_read_byte - SMBus "receive byte" protocol | |
97 | * @client: Handle to slave device | |
98 | * | |
99 | * This executes the SMBus "receive byte" protocol, returning negative errno | |
100 | * else the byte received from the device. | |
101 | */ | |
102 | s32 i2c_smbus_read_byte(const struct i2c_client *client) | |
103 | { | |
104 | union i2c_smbus_data data; | |
105 | int status; | |
106 | ||
107 | status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
108 | I2C_SMBUS_READ, 0, | |
109 | I2C_SMBUS_BYTE, &data); | |
110 | return (status < 0) ? status : data.byte; | |
111 | } | |
112 | EXPORT_SYMBOL(i2c_smbus_read_byte); | |
113 | ||
114 | /** | |
115 | * i2c_smbus_write_byte - SMBus "send byte" protocol | |
116 | * @client: Handle to slave device | |
117 | * @value: Byte to be sent | |
118 | * | |
119 | * This executes the SMBus "send byte" protocol, returning negative errno | |
120 | * else zero on success. | |
121 | */ | |
122 | s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value) | |
123 | { | |
124 | return i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
125 | I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL); | |
126 | } | |
127 | EXPORT_SYMBOL(i2c_smbus_write_byte); | |
128 | ||
129 | /** | |
130 | * i2c_smbus_read_byte_data - SMBus "read byte" protocol | |
131 | * @client: Handle to slave device | |
132 | * @command: Byte interpreted by slave | |
133 | * | |
134 | * This executes the SMBus "read byte" protocol, returning negative errno | |
135 | * else a data byte received from the device. | |
136 | */ | |
137 | s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command) | |
138 | { | |
139 | union i2c_smbus_data data; | |
140 | int status; | |
141 | ||
142 | status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
143 | I2C_SMBUS_READ, command, | |
144 | I2C_SMBUS_BYTE_DATA, &data); | |
145 | return (status < 0) ? status : data.byte; | |
146 | } | |
147 | EXPORT_SYMBOL(i2c_smbus_read_byte_data); | |
148 | ||
149 | /** | |
150 | * i2c_smbus_write_byte_data - SMBus "write byte" protocol | |
151 | * @client: Handle to slave device | |
152 | * @command: Byte interpreted by slave | |
153 | * @value: Byte being written | |
154 | * | |
155 | * This executes the SMBus "write byte" protocol, returning negative errno | |
156 | * else zero on success. | |
157 | */ | |
158 | s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command, | |
159 | u8 value) | |
160 | { | |
161 | union i2c_smbus_data data; | |
162 | data.byte = value; | |
163 | return i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
164 | I2C_SMBUS_WRITE, command, | |
165 | I2C_SMBUS_BYTE_DATA, &data); | |
166 | } | |
167 | EXPORT_SYMBOL(i2c_smbus_write_byte_data); | |
168 | ||
169 | /** | |
170 | * i2c_smbus_read_word_data - SMBus "read word" protocol | |
171 | * @client: Handle to slave device | |
172 | * @command: Byte interpreted by slave | |
173 | * | |
174 | * This executes the SMBus "read word" protocol, returning negative errno | |
175 | * else a 16-bit unsigned "word" received from the device. | |
176 | */ | |
177 | s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command) | |
178 | { | |
179 | union i2c_smbus_data data; | |
180 | int status; | |
181 | ||
182 | status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
183 | I2C_SMBUS_READ, command, | |
184 | I2C_SMBUS_WORD_DATA, &data); | |
185 | return (status < 0) ? status : data.word; | |
186 | } | |
187 | EXPORT_SYMBOL(i2c_smbus_read_word_data); | |
188 | ||
189 | /** | |
190 | * i2c_smbus_write_word_data - SMBus "write word" protocol | |
191 | * @client: Handle to slave device | |
192 | * @command: Byte interpreted by slave | |
193 | * @value: 16-bit "word" being written | |
194 | * | |
195 | * This executes the SMBus "write word" protocol, returning negative errno | |
196 | * else zero on success. | |
197 | */ | |
198 | s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command, | |
199 | u16 value) | |
200 | { | |
201 | union i2c_smbus_data data; | |
202 | data.word = value; | |
203 | return i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
204 | I2C_SMBUS_WRITE, command, | |
205 | I2C_SMBUS_WORD_DATA, &data); | |
206 | } | |
207 | EXPORT_SYMBOL(i2c_smbus_write_word_data); | |
208 | ||
209 | /** | |
210 | * i2c_smbus_read_block_data - SMBus "block read" protocol | |
211 | * @client: Handle to slave device | |
212 | * @command: Byte interpreted by slave | |
213 | * @values: Byte array into which data will be read; big enough to hold | |
214 | * the data returned by the slave. SMBus allows at most 32 bytes. | |
215 | * | |
216 | * This executes the SMBus "block read" protocol, returning negative errno | |
217 | * else the number of data bytes in the slave's response. | |
218 | * | |
219 | * Note that using this function requires that the client's adapter support | |
220 | * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers | |
221 | * support this; its emulation through I2C messaging relies on a specific | |
222 | * mechanism (I2C_M_RECV_LEN) which may not be implemented. | |
223 | */ | |
224 | s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command, | |
225 | u8 *values) | |
226 | { | |
227 | union i2c_smbus_data data; | |
228 | int status; | |
229 | ||
230 | status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
231 | I2C_SMBUS_READ, command, | |
232 | I2C_SMBUS_BLOCK_DATA, &data); | |
233 | if (status) | |
234 | return status; | |
235 | ||
236 | memcpy(values, &data.block[1], data.block[0]); | |
237 | return data.block[0]; | |
238 | } | |
239 | EXPORT_SYMBOL(i2c_smbus_read_block_data); | |
240 | ||
241 | /** | |
242 | * i2c_smbus_write_block_data - SMBus "block write" protocol | |
243 | * @client: Handle to slave device | |
244 | * @command: Byte interpreted by slave | |
245 | * @length: Size of data block; SMBus allows at most 32 bytes | |
246 | * @values: Byte array which will be written. | |
247 | * | |
248 | * This executes the SMBus "block write" protocol, returning negative errno | |
249 | * else zero on success. | |
250 | */ | |
251 | s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command, | |
252 | u8 length, const u8 *values) | |
253 | { | |
254 | union i2c_smbus_data data; | |
255 | ||
256 | if (length > I2C_SMBUS_BLOCK_MAX) | |
257 | length = I2C_SMBUS_BLOCK_MAX; | |
258 | data.block[0] = length; | |
259 | memcpy(&data.block[1], values, length); | |
260 | return i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
261 | I2C_SMBUS_WRITE, command, | |
262 | I2C_SMBUS_BLOCK_DATA, &data); | |
263 | } | |
264 | EXPORT_SYMBOL(i2c_smbus_write_block_data); | |
265 | ||
266 | /* Returns the number of read bytes */ | |
267 | s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command, | |
268 | u8 length, u8 *values) | |
269 | { | |
270 | union i2c_smbus_data data; | |
271 | int status; | |
272 | ||
273 | if (length > I2C_SMBUS_BLOCK_MAX) | |
274 | length = I2C_SMBUS_BLOCK_MAX; | |
275 | data.block[0] = length; | |
276 | status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
277 | I2C_SMBUS_READ, command, | |
278 | I2C_SMBUS_I2C_BLOCK_DATA, &data); | |
279 | if (status < 0) | |
280 | return status; | |
281 | ||
282 | memcpy(values, &data.block[1], data.block[0]); | |
283 | return data.block[0]; | |
284 | } | |
285 | EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data); | |
286 | ||
287 | s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command, | |
288 | u8 length, const u8 *values) | |
289 | { | |
290 | union i2c_smbus_data data; | |
291 | ||
292 | if (length > I2C_SMBUS_BLOCK_MAX) | |
293 | length = I2C_SMBUS_BLOCK_MAX; | |
294 | data.block[0] = length; | |
295 | memcpy(data.block + 1, values, length); | |
296 | return i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
297 | I2C_SMBUS_WRITE, command, | |
298 | I2C_SMBUS_I2C_BLOCK_DATA, &data); | |
299 | } | |
300 | EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data); | |
301 | ||
8a77821e WS |
302 | static void i2c_smbus_try_get_dmabuf(struct i2c_msg *msg, u8 init_val) |
303 | { | |
304 | bool is_read = msg->flags & I2C_M_RD; | |
305 | unsigned char *dma_buf; | |
306 | ||
307 | dma_buf = kzalloc(I2C_SMBUS_BLOCK_MAX + (is_read ? 2 : 3), GFP_KERNEL); | |
308 | if (!dma_buf) | |
309 | return; | |
310 | ||
311 | msg->buf = dma_buf; | |
312 | msg->flags |= I2C_M_DMA_SAFE; | |
313 | ||
314 | if (init_val) | |
315 | msg->buf[0] = init_val; | |
316 | } | |
317 | ||
be5b9280 WS |
318 | /* |
319 | * Simulate a SMBus command using the I2C protocol. | |
320 | * No checking of parameters is done! | |
321 | */ | |
22c78d1c WS |
322 | static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr, |
323 | unsigned short flags, | |
324 | char read_write, u8 command, int size, | |
325 | union i2c_smbus_data *data) | |
326 | { | |
be5b9280 WS |
327 | /* |
328 | * So we need to generate a series of msgs. In the case of writing, we | |
329 | * need to use only one message; when reading, we need two. We | |
330 | * initialize most things with sane defaults, to keep the code below | |
331 | * somewhat simpler. | |
332 | */ | |
22c78d1c WS |
333 | unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3]; |
334 | unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2]; | |
0390bdd4 | 335 | int nmsgs = read_write == I2C_SMBUS_READ ? 2 : 1; |
22c78d1c WS |
336 | u8 partial_pec = 0; |
337 | int status; | |
338 | struct i2c_msg msg[2] = { | |
339 | { | |
340 | .addr = addr, | |
341 | .flags = flags, | |
342 | .len = 1, | |
343 | .buf = msgbuf0, | |
344 | }, { | |
345 | .addr = addr, | |
346 | .flags = flags | I2C_M_RD, | |
347 | .len = 0, | |
348 | .buf = msgbuf1, | |
349 | }, | |
350 | }; | |
265fec2a WS |
351 | bool wants_pec = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK |
352 | && size != I2C_SMBUS_I2C_BLOCK_DATA); | |
22c78d1c WS |
353 | |
354 | msgbuf0[0] = command; | |
355 | switch (size) { | |
356 | case I2C_SMBUS_QUICK: | |
357 | msg[0].len = 0; | |
358 | /* Special case: The read/write field is used as data */ | |
359 | msg[0].flags = flags | (read_write == I2C_SMBUS_READ ? | |
360 | I2C_M_RD : 0); | |
0390bdd4 | 361 | nmsgs = 1; |
22c78d1c WS |
362 | break; |
363 | case I2C_SMBUS_BYTE: | |
364 | if (read_write == I2C_SMBUS_READ) { | |
365 | /* Special case: only a read! */ | |
366 | msg[0].flags = I2C_M_RD | flags; | |
0390bdd4 | 367 | nmsgs = 1; |
22c78d1c WS |
368 | } |
369 | break; | |
370 | case I2C_SMBUS_BYTE_DATA: | |
371 | if (read_write == I2C_SMBUS_READ) | |
372 | msg[1].len = 1; | |
373 | else { | |
374 | msg[0].len = 2; | |
375 | msgbuf0[1] = data->byte; | |
376 | } | |
377 | break; | |
378 | case I2C_SMBUS_WORD_DATA: | |
379 | if (read_write == I2C_SMBUS_READ) | |
380 | msg[1].len = 2; | |
381 | else { | |
382 | msg[0].len = 3; | |
383 | msgbuf0[1] = data->word & 0xff; | |
384 | msgbuf0[2] = data->word >> 8; | |
385 | } | |
386 | break; | |
387 | case I2C_SMBUS_PROC_CALL: | |
0390bdd4 | 388 | nmsgs = 2; /* Special case */ |
22c78d1c WS |
389 | read_write = I2C_SMBUS_READ; |
390 | msg[0].len = 3; | |
391 | msg[1].len = 2; | |
392 | msgbuf0[1] = data->word & 0xff; | |
393 | msgbuf0[2] = data->word >> 8; | |
394 | break; | |
395 | case I2C_SMBUS_BLOCK_DATA: | |
396 | if (read_write == I2C_SMBUS_READ) { | |
397 | msg[1].flags |= I2C_M_RECV_LEN; | |
398 | msg[1].len = 1; /* block length will be added by | |
399 | the underlying bus driver */ | |
8a77821e | 400 | i2c_smbus_try_get_dmabuf(&msg[1], 0); |
22c78d1c WS |
401 | } else { |
402 | msg[0].len = data->block[0] + 2; | |
403 | if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) { | |
404 | dev_err(&adapter->dev, | |
405 | "Invalid block write size %d\n", | |
406 | data->block[0]); | |
407 | return -EINVAL; | |
408 | } | |
8a77821e WS |
409 | |
410 | i2c_smbus_try_get_dmabuf(&msg[0], command); | |
f0535df0 | 411 | memcpy(msg[0].buf + 1, data->block, msg[0].len - 1); |
22c78d1c WS |
412 | } |
413 | break; | |
414 | case I2C_SMBUS_BLOCK_PROC_CALL: | |
0390bdd4 | 415 | nmsgs = 2; /* Another special case */ |
22c78d1c WS |
416 | read_write = I2C_SMBUS_READ; |
417 | if (data->block[0] > I2C_SMBUS_BLOCK_MAX) { | |
418 | dev_err(&adapter->dev, | |
419 | "Invalid block write size %d\n", | |
420 | data->block[0]); | |
421 | return -EINVAL; | |
422 | } | |
8a77821e | 423 | |
22c78d1c | 424 | msg[0].len = data->block[0] + 2; |
8a77821e | 425 | i2c_smbus_try_get_dmabuf(&msg[0], command); |
f0535df0 | 426 | memcpy(msg[0].buf + 1, data->block, msg[0].len - 1); |
8a77821e | 427 | |
22c78d1c WS |
428 | msg[1].flags |= I2C_M_RECV_LEN; |
429 | msg[1].len = 1; /* block length will be added by | |
430 | the underlying bus driver */ | |
8a77821e | 431 | i2c_smbus_try_get_dmabuf(&msg[1], 0); |
22c78d1c WS |
432 | break; |
433 | case I2C_SMBUS_I2C_BLOCK_DATA: | |
89c6efa6 JC |
434 | if (data->block[0] > I2C_SMBUS_BLOCK_MAX) { |
435 | dev_err(&adapter->dev, "Invalid block %s size %d\n", | |
436 | read_write == I2C_SMBUS_READ ? "read" : "write", | |
437 | data->block[0]); | |
438 | return -EINVAL; | |
439 | } | |
440 | ||
22c78d1c WS |
441 | if (read_write == I2C_SMBUS_READ) { |
442 | msg[1].len = data->block[0]; | |
8a77821e | 443 | i2c_smbus_try_get_dmabuf(&msg[1], 0); |
22c78d1c WS |
444 | } else { |
445 | msg[0].len = data->block[0] + 1; | |
8a77821e WS |
446 | |
447 | i2c_smbus_try_get_dmabuf(&msg[0], command); | |
f0535df0 | 448 | memcpy(msg[0].buf + 1, data->block + 1, data->block[0]); |
22c78d1c WS |
449 | } |
450 | break; | |
451 | default: | |
452 | dev_err(&adapter->dev, "Unsupported transaction %d\n", size); | |
453 | return -EOPNOTSUPP; | |
454 | } | |
455 | ||
265fec2a | 456 | if (wants_pec) { |
22c78d1c WS |
457 | /* Compute PEC if first message is a write */ |
458 | if (!(msg[0].flags & I2C_M_RD)) { | |
0390bdd4 | 459 | if (nmsgs == 1) /* Write only */ |
22c78d1c WS |
460 | i2c_smbus_add_pec(&msg[0]); |
461 | else /* Write followed by read */ | |
462 | partial_pec = i2c_smbus_msg_pec(0, &msg[0]); | |
463 | } | |
464 | /* Ask for PEC if last message is a read */ | |
0390bdd4 WS |
465 | if (msg[nmsgs - 1].flags & I2C_M_RD) |
466 | msg[nmsgs - 1].len++; | |
22c78d1c WS |
467 | } |
468 | ||
0390bdd4 | 469 | status = __i2c_transfer(adapter, msg, nmsgs); |
22c78d1c | 470 | if (status < 0) |
9aa61367 | 471 | goto cleanup; |
0390bdd4 | 472 | if (status != nmsgs) { |
9aa61367 PR |
473 | status = -EIO; |
474 | goto cleanup; | |
475 | } | |
476 | status = 0; | |
22c78d1c WS |
477 | |
478 | /* Check PEC if last message is a read */ | |
0390bdd4 WS |
479 | if (wants_pec && (msg[nmsgs - 1].flags & I2C_M_RD)) { |
480 | status = i2c_smbus_check_pec(partial_pec, &msg[nmsgs - 1]); | |
22c78d1c | 481 | if (status < 0) |
9aa61367 | 482 | goto cleanup; |
22c78d1c WS |
483 | } |
484 | ||
485 | if (read_write == I2C_SMBUS_READ) | |
486 | switch (size) { | |
487 | case I2C_SMBUS_BYTE: | |
488 | data->byte = msgbuf0[0]; | |
489 | break; | |
490 | case I2C_SMBUS_BYTE_DATA: | |
491 | data->byte = msgbuf1[0]; | |
492 | break; | |
493 | case I2C_SMBUS_WORD_DATA: | |
494 | case I2C_SMBUS_PROC_CALL: | |
495 | data->word = msgbuf1[0] | (msgbuf1[1] << 8); | |
496 | break; | |
497 | case I2C_SMBUS_I2C_BLOCK_DATA: | |
f0535df0 | 498 | memcpy(data->block + 1, msg[1].buf, data->block[0]); |
22c78d1c WS |
499 | break; |
500 | case I2C_SMBUS_BLOCK_DATA: | |
501 | case I2C_SMBUS_BLOCK_PROC_CALL: | |
40e05200 MR |
502 | if (msg[1].buf[0] > I2C_SMBUS_BLOCK_MAX) { |
503 | dev_err(&adapter->dev, | |
504 | "Invalid block size returned: %d\n", | |
505 | msg[1].buf[0]); | |
506 | status = -EPROTO; | |
507 | goto cleanup; | |
508 | } | |
f0535df0 | 509 | memcpy(data->block, msg[1].buf, msg[1].buf[0] + 1); |
22c78d1c WS |
510 | break; |
511 | } | |
8a77821e | 512 | |
9aa61367 | 513 | cleanup: |
8a77821e WS |
514 | if (msg[0].flags & I2C_M_DMA_SAFE) |
515 | kfree(msg[0].buf); | |
516 | if (msg[1].flags & I2C_M_DMA_SAFE) | |
517 | kfree(msg[1].buf); | |
518 | ||
9aa61367 | 519 | return status; |
22c78d1c WS |
520 | } |
521 | ||
522 | /** | |
523 | * i2c_smbus_xfer - execute SMBus protocol operations | |
524 | * @adapter: Handle to I2C bus | |
525 | * @addr: Address of SMBus slave on that bus | |
526 | * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC) | |
527 | * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE | |
528 | * @command: Byte interpreted by slave, for protocols which use such bytes | |
529 | * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL | |
530 | * @data: Data to be read or written | |
531 | * | |
532 | * This executes an SMBus protocol operation, and returns a negative | |
533 | * errno code else zero on success. | |
534 | */ | |
eef5ba1a PR |
535 | s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, |
536 | unsigned short flags, char read_write, | |
537 | u8 command, int protocol, union i2c_smbus_data *data) | |
538 | { | |
539 | s32 res; | |
540 | ||
83c42212 WS |
541 | res = __i2c_lock_bus_helper(adapter); |
542 | if (res) | |
543 | return res; | |
544 | ||
eef5ba1a PR |
545 | res = __i2c_smbus_xfer(adapter, addr, flags, read_write, |
546 | command, protocol, data); | |
547 | i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT); | |
548 | ||
549 | return res; | |
550 | } | |
551 | EXPORT_SYMBOL(i2c_smbus_xfer); | |
552 | ||
553 | s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, | |
554 | unsigned short flags, char read_write, | |
555 | u8 command, int protocol, union i2c_smbus_data *data) | |
22c78d1c | 556 | { |
63b96983 WS |
557 | int (*xfer_func)(struct i2c_adapter *adap, u16 addr, |
558 | unsigned short flags, char read_write, | |
559 | u8 command, int size, union i2c_smbus_data *data); | |
22c78d1c WS |
560 | unsigned long orig_jiffies; |
561 | int try; | |
562 | s32 res; | |
563 | ||
5d756112 WS |
564 | res = __i2c_check_suspended(adapter); |
565 | if (res) | |
566 | return res; | |
567 | ||
22c78d1c WS |
568 | /* If enabled, the following two tracepoints are conditional on |
569 | * read_write and protocol. | |
570 | */ | |
571 | trace_smbus_write(adapter, addr, flags, read_write, | |
572 | command, protocol, data); | |
573 | trace_smbus_read(adapter, addr, flags, read_write, | |
574 | command, protocol); | |
575 | ||
576 | flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB; | |
577 | ||
63b96983 WS |
578 | xfer_func = adapter->algo->smbus_xfer; |
579 | if (i2c_in_atomic_xfer_mode()) { | |
580 | if (adapter->algo->smbus_xfer_atomic) | |
581 | xfer_func = adapter->algo->smbus_xfer_atomic; | |
582 | else if (adapter->algo->master_xfer_atomic) | |
583 | xfer_func = NULL; /* fallback to I2C emulation */ | |
584 | } | |
585 | ||
586 | if (xfer_func) { | |
22c78d1c WS |
587 | /* Retry automatically on arbitration loss */ |
588 | orig_jiffies = jiffies; | |
589 | for (res = 0, try = 0; try <= adapter->retries; try++) { | |
63b96983 WS |
590 | res = xfer_func(adapter, addr, flags, read_write, |
591 | command, protocol, data); | |
22c78d1c WS |
592 | if (res != -EAGAIN) |
593 | break; | |
594 | if (time_after(jiffies, | |
595 | orig_jiffies + adapter->timeout)) | |
596 | break; | |
597 | } | |
22c78d1c WS |
598 | |
599 | if (res != -EOPNOTSUPP || !adapter->algo->master_xfer) | |
600 | goto trace; | |
601 | /* | |
602 | * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't | |
603 | * implement native support for the SMBus operation. | |
604 | */ | |
605 | } | |
606 | ||
607 | res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write, | |
608 | command, protocol, data); | |
609 | ||
610 | trace: | |
611 | /* If enabled, the reply tracepoint is conditional on read_write. */ | |
612 | trace_smbus_reply(adapter, addr, flags, read_write, | |
d8434c31 | 613 | command, protocol, data, res); |
22c78d1c WS |
614 | trace_smbus_result(adapter, addr, flags, read_write, |
615 | command, protocol, res); | |
616 | ||
617 | return res; | |
618 | } | |
eef5ba1a | 619 | EXPORT_SYMBOL(__i2c_smbus_xfer); |
22c78d1c WS |
620 | |
621 | /** | |
622 | * i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate | |
623 | * @client: Handle to slave device | |
624 | * @command: Byte interpreted by slave | |
625 | * @length: Size of data block; SMBus allows at most I2C_SMBUS_BLOCK_MAX bytes | |
626 | * @values: Byte array into which data will be read; big enough to hold | |
627 | * the data returned by the slave. SMBus allows at most | |
628 | * I2C_SMBUS_BLOCK_MAX bytes. | |
629 | * | |
630 | * This executes the SMBus "block read" protocol if supported by the adapter. | |
631 | * If block read is not supported, it emulates it using either word or byte | |
632 | * read protocols depending on availability. | |
633 | * | |
634 | * The addresses of the I2C slave device that are accessed with this function | |
635 | * must be mapped to a linear region, so that a block read will have the same | |
636 | * effect as a byte read. Before using this function you must double-check | |
637 | * if the I2C slave does support exchanging a block transfer with a byte | |
638 | * transfer. | |
639 | */ | |
640 | s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client, | |
641 | u8 command, u8 length, u8 *values) | |
642 | { | |
643 | u8 i = 0; | |
644 | int status; | |
645 | ||
646 | if (length > I2C_SMBUS_BLOCK_MAX) | |
647 | length = I2C_SMBUS_BLOCK_MAX; | |
648 | ||
649 | if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) | |
650 | return i2c_smbus_read_i2c_block_data(client, command, length, values); | |
651 | ||
652 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) | |
653 | return -EOPNOTSUPP; | |
654 | ||
655 | if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) { | |
656 | while ((i + 2) <= length) { | |
657 | status = i2c_smbus_read_word_data(client, command + i); | |
658 | if (status < 0) | |
659 | return status; | |
660 | values[i] = status & 0xff; | |
661 | values[i + 1] = status >> 8; | |
662 | i += 2; | |
663 | } | |
664 | } | |
665 | ||
666 | while (i < length) { | |
667 | status = i2c_smbus_read_byte_data(client, command + i); | |
668 | if (status < 0) | |
669 | return status; | |
670 | values[i] = status; | |
671 | i++; | |
672 | } | |
673 | ||
674 | return i; | |
675 | } | |
676 | EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated); | |
3c0a60be PR |
677 | |
678 | /** | |
ed680522 | 679 | * i2c_new_smbus_alert_device - get ara client for SMBus alert support |
3c0a60be PR |
680 | * @adapter: the target adapter |
681 | * @setup: setup data for the SMBus alert handler | |
682 | * Context: can sleep | |
683 | * | |
684 | * Setup handling of the SMBus alert protocol on a given I2C bus segment. | |
685 | * | |
686 | * Handling can be done either through our IRQ handler, or by the | |
687 | * adapter (from its handler, periodic polling, or whatever). | |
688 | * | |
3c0a60be | 689 | * This returns the ara client, which should be saved for later use with |
ed680522 WS |
690 | * i2c_handle_smbus_alert() and ultimately i2c_unregister_device(); or an |
691 | * ERRPTR to indicate an error. | |
3c0a60be | 692 | */ |
ed680522 WS |
693 | struct i2c_client *i2c_new_smbus_alert_device(struct i2c_adapter *adapter, |
694 | struct i2c_smbus_alert_setup *setup) | |
3c0a60be PR |
695 | { |
696 | struct i2c_board_info ara_board_info = { | |
697 | I2C_BOARD_INFO("smbus_alert", 0x0c), | |
698 | .platform_data = setup, | |
699 | }; | |
700 | ||
ed680522 | 701 | return i2c_new_client_device(adapter, &ara_board_info); |
3c0a60be | 702 | } |
ed680522 | 703 | EXPORT_SYMBOL_GPL(i2c_new_smbus_alert_device); |
69d17246 | 704 | |
a263a840 A |
705 | #if IS_ENABLED(CONFIG_I2C_SMBUS) |
706 | int i2c_setup_smbus_alert(struct i2c_adapter *adapter) | |
69d17246 | 707 | { |
8302532f | 708 | struct device *parent = adapter->dev.parent; |
69d17246 PR |
709 | int irq; |
710 | ||
8302532f AS |
711 | /* Adapter instantiated without parent, skip the SMBus alert setup */ |
712 | if (!parent) | |
713 | return 0; | |
714 | ||
715 | irq = device_property_match_string(parent, "interrupt-names", "smbus_alert"); | |
69d17246 PR |
716 | if (irq == -EINVAL || irq == -ENODATA) |
717 | return 0; | |
718 | else if (irq < 0) | |
719 | return irq; | |
720 | ||
ed680522 | 721 | return PTR_ERR_OR_ZERO(i2c_new_smbus_alert_device(adapter, NULL)); |
69d17246 | 722 | } |
69d17246 | 723 | #endif |