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> |
8a77821e | 17 | #include <linux/slab.h> |
22c78d1c | 18 | |
83c42212 WS |
19 | #include "i2c-core.h" |
20 | ||
22c78d1c WS |
21 | #define CREATE_TRACE_POINTS |
22 | #include <trace/events/smbus.h> | |
23 | ||
24 | ||
25 | /* The SMBus parts */ | |
26 | ||
27 | #define POLY (0x1070U << 3) | |
28 | static u8 crc8(u16 data) | |
29 | { | |
30 | int i; | |
31 | ||
32 | for (i = 0; i < 8; i++) { | |
33 | if (data & 0x8000) | |
34 | data = data ^ POLY; | |
35 | data = data << 1; | |
36 | } | |
37 | return (u8)(data >> 8); | |
38 | } | |
39 | ||
40 | /* Incremental CRC8 over count bytes in the array pointed to by p */ | |
41 | static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count) | |
42 | { | |
43 | int i; | |
44 | ||
45 | for (i = 0; i < count; i++) | |
46 | crc = crc8((crc ^ p[i]) << 8); | |
47 | return crc; | |
48 | } | |
49 | ||
50 | /* Assume a 7-bit address, which is reasonable for SMBus */ | |
51 | static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg) | |
52 | { | |
53 | /* The address will be sent first */ | |
54 | u8 addr = i2c_8bit_addr_from_msg(msg); | |
55 | pec = i2c_smbus_pec(pec, &addr, 1); | |
56 | ||
57 | /* The data buffer follows */ | |
58 | return i2c_smbus_pec(pec, msg->buf, msg->len); | |
59 | } | |
60 | ||
61 | /* Used for write only transactions */ | |
62 | static inline void i2c_smbus_add_pec(struct i2c_msg *msg) | |
63 | { | |
64 | msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg); | |
65 | msg->len++; | |
66 | } | |
67 | ||
68 | /* Return <0 on CRC error | |
69 | If there was a write before this read (most cases) we need to take the | |
70 | partial CRC from the write part into account. | |
71 | Note that this function does modify the message (we need to decrease the | |
72 | message length to hide the CRC byte from the caller). */ | |
73 | static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg) | |
74 | { | |
75 | u8 rpec = msg->buf[--msg->len]; | |
76 | cpec = i2c_smbus_msg_pec(cpec, msg); | |
77 | ||
78 | if (rpec != cpec) { | |
79 | pr_debug("Bad PEC 0x%02x vs. 0x%02x\n", | |
80 | rpec, cpec); | |
81 | return -EBADMSG; | |
82 | } | |
83 | return 0; | |
84 | } | |
85 | ||
86 | /** | |
87 | * i2c_smbus_read_byte - SMBus "receive byte" protocol | |
88 | * @client: Handle to slave device | |
89 | * | |
90 | * This executes the SMBus "receive byte" protocol, returning negative errno | |
91 | * else the byte received from the device. | |
92 | */ | |
93 | s32 i2c_smbus_read_byte(const struct i2c_client *client) | |
94 | { | |
95 | union i2c_smbus_data data; | |
96 | int status; | |
97 | ||
98 | status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
99 | I2C_SMBUS_READ, 0, | |
100 | I2C_SMBUS_BYTE, &data); | |
101 | return (status < 0) ? status : data.byte; | |
102 | } | |
103 | EXPORT_SYMBOL(i2c_smbus_read_byte); | |
104 | ||
105 | /** | |
106 | * i2c_smbus_write_byte - SMBus "send byte" protocol | |
107 | * @client: Handle to slave device | |
108 | * @value: Byte to be sent | |
109 | * | |
110 | * This executes the SMBus "send byte" protocol, returning negative errno | |
111 | * else zero on success. | |
112 | */ | |
113 | s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value) | |
114 | { | |
115 | return i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
116 | I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL); | |
117 | } | |
118 | EXPORT_SYMBOL(i2c_smbus_write_byte); | |
119 | ||
120 | /** | |
121 | * i2c_smbus_read_byte_data - SMBus "read byte" protocol | |
122 | * @client: Handle to slave device | |
123 | * @command: Byte interpreted by slave | |
124 | * | |
125 | * This executes the SMBus "read byte" protocol, returning negative errno | |
126 | * else a data byte received from the device. | |
127 | */ | |
128 | s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command) | |
129 | { | |
130 | union i2c_smbus_data data; | |
131 | int status; | |
132 | ||
133 | status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
134 | I2C_SMBUS_READ, command, | |
135 | I2C_SMBUS_BYTE_DATA, &data); | |
136 | return (status < 0) ? status : data.byte; | |
137 | } | |
138 | EXPORT_SYMBOL(i2c_smbus_read_byte_data); | |
139 | ||
140 | /** | |
141 | * i2c_smbus_write_byte_data - SMBus "write byte" protocol | |
142 | * @client: Handle to slave device | |
143 | * @command: Byte interpreted by slave | |
144 | * @value: Byte being written | |
145 | * | |
146 | * This executes the SMBus "write byte" protocol, returning negative errno | |
147 | * else zero on success. | |
148 | */ | |
149 | s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command, | |
150 | u8 value) | |
151 | { | |
152 | union i2c_smbus_data data; | |
153 | data.byte = value; | |
154 | return i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
155 | I2C_SMBUS_WRITE, command, | |
156 | I2C_SMBUS_BYTE_DATA, &data); | |
157 | } | |
158 | EXPORT_SYMBOL(i2c_smbus_write_byte_data); | |
159 | ||
160 | /** | |
161 | * i2c_smbus_read_word_data - SMBus "read word" protocol | |
162 | * @client: Handle to slave device | |
163 | * @command: Byte interpreted by slave | |
164 | * | |
165 | * This executes the SMBus "read word" protocol, returning negative errno | |
166 | * else a 16-bit unsigned "word" received from the device. | |
167 | */ | |
168 | s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command) | |
169 | { | |
170 | union i2c_smbus_data data; | |
171 | int status; | |
172 | ||
173 | status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
174 | I2C_SMBUS_READ, command, | |
175 | I2C_SMBUS_WORD_DATA, &data); | |
176 | return (status < 0) ? status : data.word; | |
177 | } | |
178 | EXPORT_SYMBOL(i2c_smbus_read_word_data); | |
179 | ||
180 | /** | |
181 | * i2c_smbus_write_word_data - SMBus "write word" protocol | |
182 | * @client: Handle to slave device | |
183 | * @command: Byte interpreted by slave | |
184 | * @value: 16-bit "word" being written | |
185 | * | |
186 | * This executes the SMBus "write word" protocol, returning negative errno | |
187 | * else zero on success. | |
188 | */ | |
189 | s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command, | |
190 | u16 value) | |
191 | { | |
192 | union i2c_smbus_data data; | |
193 | data.word = value; | |
194 | return i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
195 | I2C_SMBUS_WRITE, command, | |
196 | I2C_SMBUS_WORD_DATA, &data); | |
197 | } | |
198 | EXPORT_SYMBOL(i2c_smbus_write_word_data); | |
199 | ||
200 | /** | |
201 | * i2c_smbus_read_block_data - SMBus "block read" protocol | |
202 | * @client: Handle to slave device | |
203 | * @command: Byte interpreted by slave | |
204 | * @values: Byte array into which data will be read; big enough to hold | |
205 | * the data returned by the slave. SMBus allows at most 32 bytes. | |
206 | * | |
207 | * This executes the SMBus "block read" protocol, returning negative errno | |
208 | * else the number of data bytes in the slave's response. | |
209 | * | |
210 | * Note that using this function requires that the client's adapter support | |
211 | * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers | |
212 | * support this; its emulation through I2C messaging relies on a specific | |
213 | * mechanism (I2C_M_RECV_LEN) which may not be implemented. | |
214 | */ | |
215 | s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command, | |
216 | u8 *values) | |
217 | { | |
218 | union i2c_smbus_data data; | |
219 | int status; | |
220 | ||
221 | status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
222 | I2C_SMBUS_READ, command, | |
223 | I2C_SMBUS_BLOCK_DATA, &data); | |
224 | if (status) | |
225 | return status; | |
226 | ||
227 | memcpy(values, &data.block[1], data.block[0]); | |
228 | return data.block[0]; | |
229 | } | |
230 | EXPORT_SYMBOL(i2c_smbus_read_block_data); | |
231 | ||
232 | /** | |
233 | * i2c_smbus_write_block_data - SMBus "block write" protocol | |
234 | * @client: Handle to slave device | |
235 | * @command: Byte interpreted by slave | |
236 | * @length: Size of data block; SMBus allows at most 32 bytes | |
237 | * @values: Byte array which will be written. | |
238 | * | |
239 | * This executes the SMBus "block write" protocol, returning negative errno | |
240 | * else zero on success. | |
241 | */ | |
242 | s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command, | |
243 | u8 length, const u8 *values) | |
244 | { | |
245 | union i2c_smbus_data data; | |
246 | ||
247 | if (length > I2C_SMBUS_BLOCK_MAX) | |
248 | length = I2C_SMBUS_BLOCK_MAX; | |
249 | data.block[0] = length; | |
250 | memcpy(&data.block[1], values, length); | |
251 | return i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
252 | I2C_SMBUS_WRITE, command, | |
253 | I2C_SMBUS_BLOCK_DATA, &data); | |
254 | } | |
255 | EXPORT_SYMBOL(i2c_smbus_write_block_data); | |
256 | ||
257 | /* Returns the number of read bytes */ | |
258 | s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command, | |
259 | u8 length, u8 *values) | |
260 | { | |
261 | union i2c_smbus_data data; | |
262 | int status; | |
263 | ||
264 | if (length > I2C_SMBUS_BLOCK_MAX) | |
265 | length = I2C_SMBUS_BLOCK_MAX; | |
266 | data.block[0] = length; | |
267 | status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
268 | I2C_SMBUS_READ, command, | |
269 | I2C_SMBUS_I2C_BLOCK_DATA, &data); | |
270 | if (status < 0) | |
271 | return status; | |
272 | ||
273 | memcpy(values, &data.block[1], data.block[0]); | |
274 | return data.block[0]; | |
275 | } | |
276 | EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data); | |
277 | ||
278 | s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command, | |
279 | u8 length, const u8 *values) | |
280 | { | |
281 | union i2c_smbus_data data; | |
282 | ||
283 | if (length > I2C_SMBUS_BLOCK_MAX) | |
284 | length = I2C_SMBUS_BLOCK_MAX; | |
285 | data.block[0] = length; | |
286 | memcpy(data.block + 1, values, length); | |
287 | return i2c_smbus_xfer(client->adapter, client->addr, client->flags, | |
288 | I2C_SMBUS_WRITE, command, | |
289 | I2C_SMBUS_I2C_BLOCK_DATA, &data); | |
290 | } | |
291 | EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data); | |
292 | ||
8a77821e WS |
293 | static void i2c_smbus_try_get_dmabuf(struct i2c_msg *msg, u8 init_val) |
294 | { | |
295 | bool is_read = msg->flags & I2C_M_RD; | |
296 | unsigned char *dma_buf; | |
297 | ||
298 | dma_buf = kzalloc(I2C_SMBUS_BLOCK_MAX + (is_read ? 2 : 3), GFP_KERNEL); | |
299 | if (!dma_buf) | |
300 | return; | |
301 | ||
302 | msg->buf = dma_buf; | |
303 | msg->flags |= I2C_M_DMA_SAFE; | |
304 | ||
305 | if (init_val) | |
306 | msg->buf[0] = init_val; | |
307 | } | |
308 | ||
be5b9280 WS |
309 | /* |
310 | * Simulate a SMBus command using the I2C protocol. | |
311 | * No checking of parameters is done! | |
312 | */ | |
22c78d1c WS |
313 | static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr, |
314 | unsigned short flags, | |
315 | char read_write, u8 command, int size, | |
316 | union i2c_smbus_data *data) | |
317 | { | |
be5b9280 WS |
318 | /* |
319 | * So we need to generate a series of msgs. In the case of writing, we | |
320 | * need to use only one message; when reading, we need two. We | |
321 | * initialize most things with sane defaults, to keep the code below | |
322 | * somewhat simpler. | |
323 | */ | |
22c78d1c WS |
324 | unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3]; |
325 | unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2]; | |
0390bdd4 | 326 | int nmsgs = read_write == I2C_SMBUS_READ ? 2 : 1; |
22c78d1c WS |
327 | u8 partial_pec = 0; |
328 | int status; | |
329 | struct i2c_msg msg[2] = { | |
330 | { | |
331 | .addr = addr, | |
332 | .flags = flags, | |
333 | .len = 1, | |
334 | .buf = msgbuf0, | |
335 | }, { | |
336 | .addr = addr, | |
337 | .flags = flags | I2C_M_RD, | |
338 | .len = 0, | |
339 | .buf = msgbuf1, | |
340 | }, | |
341 | }; | |
265fec2a WS |
342 | bool wants_pec = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK |
343 | && size != I2C_SMBUS_I2C_BLOCK_DATA); | |
22c78d1c WS |
344 | |
345 | msgbuf0[0] = command; | |
346 | switch (size) { | |
347 | case I2C_SMBUS_QUICK: | |
348 | msg[0].len = 0; | |
349 | /* Special case: The read/write field is used as data */ | |
350 | msg[0].flags = flags | (read_write == I2C_SMBUS_READ ? | |
351 | I2C_M_RD : 0); | |
0390bdd4 | 352 | nmsgs = 1; |
22c78d1c WS |
353 | break; |
354 | case I2C_SMBUS_BYTE: | |
355 | if (read_write == I2C_SMBUS_READ) { | |
356 | /* Special case: only a read! */ | |
357 | msg[0].flags = I2C_M_RD | flags; | |
0390bdd4 | 358 | nmsgs = 1; |
22c78d1c WS |
359 | } |
360 | break; | |
361 | case I2C_SMBUS_BYTE_DATA: | |
362 | if (read_write == I2C_SMBUS_READ) | |
363 | msg[1].len = 1; | |
364 | else { | |
365 | msg[0].len = 2; | |
366 | msgbuf0[1] = data->byte; | |
367 | } | |
368 | break; | |
369 | case I2C_SMBUS_WORD_DATA: | |
370 | if (read_write == I2C_SMBUS_READ) | |
371 | msg[1].len = 2; | |
372 | else { | |
373 | msg[0].len = 3; | |
374 | msgbuf0[1] = data->word & 0xff; | |
375 | msgbuf0[2] = data->word >> 8; | |
376 | } | |
377 | break; | |
378 | case I2C_SMBUS_PROC_CALL: | |
0390bdd4 | 379 | nmsgs = 2; /* Special case */ |
22c78d1c WS |
380 | read_write = I2C_SMBUS_READ; |
381 | msg[0].len = 3; | |
382 | msg[1].len = 2; | |
383 | msgbuf0[1] = data->word & 0xff; | |
384 | msgbuf0[2] = data->word >> 8; | |
385 | break; | |
386 | case I2C_SMBUS_BLOCK_DATA: | |
387 | if (read_write == I2C_SMBUS_READ) { | |
388 | msg[1].flags |= I2C_M_RECV_LEN; | |
389 | msg[1].len = 1; /* block length will be added by | |
390 | the underlying bus driver */ | |
8a77821e | 391 | i2c_smbus_try_get_dmabuf(&msg[1], 0); |
22c78d1c WS |
392 | } else { |
393 | msg[0].len = data->block[0] + 2; | |
394 | if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) { | |
395 | dev_err(&adapter->dev, | |
396 | "Invalid block write size %d\n", | |
397 | data->block[0]); | |
398 | return -EINVAL; | |
399 | } | |
8a77821e WS |
400 | |
401 | i2c_smbus_try_get_dmabuf(&msg[0], command); | |
f0535df0 | 402 | memcpy(msg[0].buf + 1, data->block, msg[0].len - 1); |
22c78d1c WS |
403 | } |
404 | break; | |
405 | case I2C_SMBUS_BLOCK_PROC_CALL: | |
0390bdd4 | 406 | nmsgs = 2; /* Another special case */ |
22c78d1c WS |
407 | read_write = I2C_SMBUS_READ; |
408 | if (data->block[0] > I2C_SMBUS_BLOCK_MAX) { | |
409 | dev_err(&adapter->dev, | |
410 | "Invalid block write size %d\n", | |
411 | data->block[0]); | |
412 | return -EINVAL; | |
413 | } | |
8a77821e | 414 | |
22c78d1c | 415 | msg[0].len = data->block[0] + 2; |
8a77821e | 416 | i2c_smbus_try_get_dmabuf(&msg[0], command); |
f0535df0 | 417 | memcpy(msg[0].buf + 1, data->block, msg[0].len - 1); |
8a77821e | 418 | |
22c78d1c WS |
419 | msg[1].flags |= I2C_M_RECV_LEN; |
420 | msg[1].len = 1; /* block length will be added by | |
421 | the underlying bus driver */ | |
8a77821e | 422 | i2c_smbus_try_get_dmabuf(&msg[1], 0); |
22c78d1c WS |
423 | break; |
424 | case I2C_SMBUS_I2C_BLOCK_DATA: | |
89c6efa6 JC |
425 | if (data->block[0] > I2C_SMBUS_BLOCK_MAX) { |
426 | dev_err(&adapter->dev, "Invalid block %s size %d\n", | |
427 | read_write == I2C_SMBUS_READ ? "read" : "write", | |
428 | data->block[0]); | |
429 | return -EINVAL; | |
430 | } | |
431 | ||
22c78d1c WS |
432 | if (read_write == I2C_SMBUS_READ) { |
433 | msg[1].len = data->block[0]; | |
8a77821e | 434 | i2c_smbus_try_get_dmabuf(&msg[1], 0); |
22c78d1c WS |
435 | } else { |
436 | msg[0].len = data->block[0] + 1; | |
8a77821e WS |
437 | |
438 | i2c_smbus_try_get_dmabuf(&msg[0], command); | |
f0535df0 | 439 | memcpy(msg[0].buf + 1, data->block + 1, data->block[0]); |
22c78d1c WS |
440 | } |
441 | break; | |
442 | default: | |
443 | dev_err(&adapter->dev, "Unsupported transaction %d\n", size); | |
444 | return -EOPNOTSUPP; | |
445 | } | |
446 | ||
265fec2a | 447 | if (wants_pec) { |
22c78d1c WS |
448 | /* Compute PEC if first message is a write */ |
449 | if (!(msg[0].flags & I2C_M_RD)) { | |
0390bdd4 | 450 | if (nmsgs == 1) /* Write only */ |
22c78d1c WS |
451 | i2c_smbus_add_pec(&msg[0]); |
452 | else /* Write followed by read */ | |
453 | partial_pec = i2c_smbus_msg_pec(0, &msg[0]); | |
454 | } | |
455 | /* Ask for PEC if last message is a read */ | |
0390bdd4 WS |
456 | if (msg[nmsgs - 1].flags & I2C_M_RD) |
457 | msg[nmsgs - 1].len++; | |
22c78d1c WS |
458 | } |
459 | ||
0390bdd4 | 460 | status = __i2c_transfer(adapter, msg, nmsgs); |
22c78d1c | 461 | if (status < 0) |
9aa61367 | 462 | goto cleanup; |
0390bdd4 | 463 | if (status != nmsgs) { |
9aa61367 PR |
464 | status = -EIO; |
465 | goto cleanup; | |
466 | } | |
467 | status = 0; | |
22c78d1c WS |
468 | |
469 | /* Check PEC if last message is a read */ | |
0390bdd4 WS |
470 | if (wants_pec && (msg[nmsgs - 1].flags & I2C_M_RD)) { |
471 | status = i2c_smbus_check_pec(partial_pec, &msg[nmsgs - 1]); | |
22c78d1c | 472 | if (status < 0) |
9aa61367 | 473 | goto cleanup; |
22c78d1c WS |
474 | } |
475 | ||
476 | if (read_write == I2C_SMBUS_READ) | |
477 | switch (size) { | |
478 | case I2C_SMBUS_BYTE: | |
479 | data->byte = msgbuf0[0]; | |
480 | break; | |
481 | case I2C_SMBUS_BYTE_DATA: | |
482 | data->byte = msgbuf1[0]; | |
483 | break; | |
484 | case I2C_SMBUS_WORD_DATA: | |
485 | case I2C_SMBUS_PROC_CALL: | |
486 | data->word = msgbuf1[0] | (msgbuf1[1] << 8); | |
487 | break; | |
488 | case I2C_SMBUS_I2C_BLOCK_DATA: | |
f0535df0 | 489 | memcpy(data->block + 1, msg[1].buf, data->block[0]); |
22c78d1c WS |
490 | break; |
491 | case I2C_SMBUS_BLOCK_DATA: | |
492 | case I2C_SMBUS_BLOCK_PROC_CALL: | |
40e05200 MR |
493 | if (msg[1].buf[0] > I2C_SMBUS_BLOCK_MAX) { |
494 | dev_err(&adapter->dev, | |
495 | "Invalid block size returned: %d\n", | |
496 | msg[1].buf[0]); | |
497 | status = -EPROTO; | |
498 | goto cleanup; | |
499 | } | |
f0535df0 | 500 | memcpy(data->block, msg[1].buf, msg[1].buf[0] + 1); |
22c78d1c WS |
501 | break; |
502 | } | |
8a77821e | 503 | |
9aa61367 | 504 | cleanup: |
8a77821e WS |
505 | if (msg[0].flags & I2C_M_DMA_SAFE) |
506 | kfree(msg[0].buf); | |
507 | if (msg[1].flags & I2C_M_DMA_SAFE) | |
508 | kfree(msg[1].buf); | |
509 | ||
9aa61367 | 510 | return status; |
22c78d1c WS |
511 | } |
512 | ||
513 | /** | |
514 | * i2c_smbus_xfer - execute SMBus protocol operations | |
515 | * @adapter: Handle to I2C bus | |
516 | * @addr: Address of SMBus slave on that bus | |
517 | * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC) | |
518 | * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE | |
519 | * @command: Byte interpreted by slave, for protocols which use such bytes | |
520 | * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL | |
521 | * @data: Data to be read or written | |
522 | * | |
523 | * This executes an SMBus protocol operation, and returns a negative | |
524 | * errno code else zero on success. | |
525 | */ | |
eef5ba1a PR |
526 | s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, |
527 | unsigned short flags, char read_write, | |
528 | u8 command, int protocol, union i2c_smbus_data *data) | |
529 | { | |
530 | s32 res; | |
531 | ||
83c42212 WS |
532 | res = __i2c_lock_bus_helper(adapter); |
533 | if (res) | |
534 | return res; | |
535 | ||
eef5ba1a PR |
536 | res = __i2c_smbus_xfer(adapter, addr, flags, read_write, |
537 | command, protocol, data); | |
538 | i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT); | |
539 | ||
540 | return res; | |
541 | } | |
542 | EXPORT_SYMBOL(i2c_smbus_xfer); | |
543 | ||
544 | s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, | |
545 | unsigned short flags, char read_write, | |
546 | u8 command, int protocol, union i2c_smbus_data *data) | |
22c78d1c | 547 | { |
63b96983 WS |
548 | int (*xfer_func)(struct i2c_adapter *adap, u16 addr, |
549 | unsigned short flags, char read_write, | |
550 | u8 command, int size, union i2c_smbus_data *data); | |
22c78d1c WS |
551 | unsigned long orig_jiffies; |
552 | int try; | |
553 | s32 res; | |
554 | ||
5d756112 WS |
555 | res = __i2c_check_suspended(adapter); |
556 | if (res) | |
557 | return res; | |
558 | ||
22c78d1c WS |
559 | /* If enabled, the following two tracepoints are conditional on |
560 | * read_write and protocol. | |
561 | */ | |
562 | trace_smbus_write(adapter, addr, flags, read_write, | |
563 | command, protocol, data); | |
564 | trace_smbus_read(adapter, addr, flags, read_write, | |
565 | command, protocol); | |
566 | ||
567 | flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB; | |
568 | ||
63b96983 WS |
569 | xfer_func = adapter->algo->smbus_xfer; |
570 | if (i2c_in_atomic_xfer_mode()) { | |
571 | if (adapter->algo->smbus_xfer_atomic) | |
572 | xfer_func = adapter->algo->smbus_xfer_atomic; | |
573 | else if (adapter->algo->master_xfer_atomic) | |
574 | xfer_func = NULL; /* fallback to I2C emulation */ | |
575 | } | |
576 | ||
577 | if (xfer_func) { | |
22c78d1c WS |
578 | /* Retry automatically on arbitration loss */ |
579 | orig_jiffies = jiffies; | |
580 | for (res = 0, try = 0; try <= adapter->retries; try++) { | |
63b96983 WS |
581 | res = xfer_func(adapter, addr, flags, read_write, |
582 | command, protocol, data); | |
22c78d1c WS |
583 | if (res != -EAGAIN) |
584 | break; | |
585 | if (time_after(jiffies, | |
586 | orig_jiffies + adapter->timeout)) | |
587 | break; | |
588 | } | |
22c78d1c WS |
589 | |
590 | if (res != -EOPNOTSUPP || !adapter->algo->master_xfer) | |
591 | goto trace; | |
592 | /* | |
593 | * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't | |
594 | * implement native support for the SMBus operation. | |
595 | */ | |
596 | } | |
597 | ||
598 | res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write, | |
599 | command, protocol, data); | |
600 | ||
601 | trace: | |
602 | /* If enabled, the reply tracepoint is conditional on read_write. */ | |
603 | trace_smbus_reply(adapter, addr, flags, read_write, | |
d8434c31 | 604 | command, protocol, data, res); |
22c78d1c WS |
605 | trace_smbus_result(adapter, addr, flags, read_write, |
606 | command, protocol, res); | |
607 | ||
608 | return res; | |
609 | } | |
eef5ba1a | 610 | EXPORT_SYMBOL(__i2c_smbus_xfer); |
22c78d1c WS |
611 | |
612 | /** | |
613 | * i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate | |
614 | * @client: Handle to slave device | |
615 | * @command: Byte interpreted by slave | |
616 | * @length: Size of data block; SMBus allows at most I2C_SMBUS_BLOCK_MAX bytes | |
617 | * @values: Byte array into which data will be read; big enough to hold | |
618 | * the data returned by the slave. SMBus allows at most | |
619 | * I2C_SMBUS_BLOCK_MAX bytes. | |
620 | * | |
621 | * This executes the SMBus "block read" protocol if supported by the adapter. | |
622 | * If block read is not supported, it emulates it using either word or byte | |
623 | * read protocols depending on availability. | |
624 | * | |
625 | * The addresses of the I2C slave device that are accessed with this function | |
626 | * must be mapped to a linear region, so that a block read will have the same | |
627 | * effect as a byte read. Before using this function you must double-check | |
628 | * if the I2C slave does support exchanging a block transfer with a byte | |
629 | * transfer. | |
630 | */ | |
631 | s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client, | |
632 | u8 command, u8 length, u8 *values) | |
633 | { | |
634 | u8 i = 0; | |
635 | int status; | |
636 | ||
637 | if (length > I2C_SMBUS_BLOCK_MAX) | |
638 | length = I2C_SMBUS_BLOCK_MAX; | |
639 | ||
640 | if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) | |
641 | return i2c_smbus_read_i2c_block_data(client, command, length, values); | |
642 | ||
643 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) | |
644 | return -EOPNOTSUPP; | |
645 | ||
646 | if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) { | |
647 | while ((i + 2) <= length) { | |
648 | status = i2c_smbus_read_word_data(client, command + i); | |
649 | if (status < 0) | |
650 | return status; | |
651 | values[i] = status & 0xff; | |
652 | values[i + 1] = status >> 8; | |
653 | i += 2; | |
654 | } | |
655 | } | |
656 | ||
657 | while (i < length) { | |
658 | status = i2c_smbus_read_byte_data(client, command + i); | |
659 | if (status < 0) | |
660 | return status; | |
661 | values[i] = status; | |
662 | i++; | |
663 | } | |
664 | ||
665 | return i; | |
666 | } | |
667 | EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated); | |
3c0a60be PR |
668 | |
669 | /** | |
ed680522 | 670 | * i2c_new_smbus_alert_device - get ara client for SMBus alert support |
3c0a60be PR |
671 | * @adapter: the target adapter |
672 | * @setup: setup data for the SMBus alert handler | |
673 | * Context: can sleep | |
674 | * | |
675 | * Setup handling of the SMBus alert protocol on a given I2C bus segment. | |
676 | * | |
677 | * Handling can be done either through our IRQ handler, or by the | |
678 | * adapter (from its handler, periodic polling, or whatever). | |
679 | * | |
3c0a60be | 680 | * This returns the ara client, which should be saved for later use with |
ed680522 WS |
681 | * i2c_handle_smbus_alert() and ultimately i2c_unregister_device(); or an |
682 | * ERRPTR to indicate an error. | |
3c0a60be | 683 | */ |
ed680522 WS |
684 | struct i2c_client *i2c_new_smbus_alert_device(struct i2c_adapter *adapter, |
685 | struct i2c_smbus_alert_setup *setup) | |
3c0a60be PR |
686 | { |
687 | struct i2c_board_info ara_board_info = { | |
688 | I2C_BOARD_INFO("smbus_alert", 0x0c), | |
689 | .platform_data = setup, | |
690 | }; | |
691 | ||
ed680522 | 692 | return i2c_new_client_device(adapter, &ara_board_info); |
3c0a60be | 693 | } |
ed680522 | 694 | EXPORT_SYMBOL_GPL(i2c_new_smbus_alert_device); |
69d17246 PR |
695 | |
696 | #if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_OF) | |
697 | int of_i2c_setup_smbus_alert(struct i2c_adapter *adapter) | |
698 | { | |
69d17246 PR |
699 | int irq; |
700 | ||
701 | irq = of_property_match_string(adapter->dev.of_node, "interrupt-names", | |
702 | "smbus_alert"); | |
703 | if (irq == -EINVAL || irq == -ENODATA) | |
704 | return 0; | |
705 | else if (irq < 0) | |
706 | return irq; | |
707 | ||
ed680522 | 708 | return PTR_ERR_OR_ZERO(i2c_new_smbus_alert_device(adapter, NULL)); |
69d17246 PR |
709 | } |
710 | EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert); | |
711 | #endif |