blob: 16f228dc243f3740f241a5f1315820e23f08b978 [file] [log] [blame]
Simon Glassa17d94f2013-02-25 14:08:39 -08001/*
2 * ChromeOS EC multi-function device (SPI)
3 *
4 * Copyright (C) 2012 Google, Inc
5 *
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 */
15
16#include <linux/delay.h>
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/mfd/cros_ec.h>
20#include <linux/mfd/cros_ec_commands.h>
Rhyland Klein01e73c82013-12-09 12:36:09 +010021#include <linux/of.h>
Simon Glassa17d94f2013-02-25 14:08:39 -080022#include <linux/platform_device.h>
23#include <linux/slab.h>
24#include <linux/spi/spi.h>
25
26
27/* The header byte, which follows the preamble */
28#define EC_MSG_HEADER 0xec
29
30/*
31 * Number of EC preamble bytes we read at a time. Since it takes
32 * about 400-500us for the EC to respond there is not a lot of
33 * point in tuning this. If the EC could respond faster then
34 * we could increase this so that might expect the preamble and
35 * message to occur in a single transaction. However, the maximum
36 * SPI transfer size is 256 bytes, so at 5MHz we need a response
37 * time of perhaps <320us (200 bytes / 1600 bits).
38 */
39#define EC_MSG_PREAMBLE_COUNT 32
40
41/*
Doug Anderson9c0b54a2014-04-30 10:44:07 -070042 * Allow for a long time for the EC to respond. We support i2c
43 * tunneling and support fairly long messages for the tunnel (249
44 * bytes long at the moment). If we're talking to a 100 kHz device
45 * on the other end and need to transfer ~256 bytes, then we need:
46 * 10 us/bit * ~10 bits/byte * ~256 bytes = ~25ms
47 *
48 * We'll wait 4 times that to handle clock stretching and other
49 * paranoia.
50 *
51 * It's pretty unlikely that we'll really see a 249 byte tunnel in
52 * anything other than testing. If this was more common we might
53 * consider having slow commands like this require a GET_STATUS
54 * wait loop. The 'flash write' command would be another candidate
55 * for this, clocking in at 2-3ms.
56 */
57#define EC_MSG_DEADLINE_MS 100
Simon Glassa17d94f2013-02-25 14:08:39 -080058
59/*
60 * Time between raising the SPI chip select (for the end of a
61 * transaction) and dropping it again (for the next transaction).
Derek Basehore49f91ac2013-11-18 11:30:48 +010062 * If we go too fast, the EC will miss the transaction. We know that we
63 * need at least 70 us with the 16 MHz STM32 EC, so go with 200 us to be
64 * safe.
Simon Glassa17d94f2013-02-25 14:08:39 -080065 */
Derek Basehore49f91ac2013-11-18 11:30:48 +010066#define EC_SPI_RECOVERY_TIME_NS (200 * 1000)
Simon Glassa17d94f2013-02-25 14:08:39 -080067
68/**
69 * struct cros_ec_spi - information about a SPI-connected EC
70 *
71 * @spi: SPI device we are connected to
72 * @last_transfer_ns: time that we last finished a transfer, or 0 if there
73 * if no record
Alexandru M Stanff4378f2015-06-09 13:04:49 +020074 * @start_of_msg_delay: used to set the delay_usecs on the spi_transfer that
75 * is sent when we want to turn on CS at the start of a transaction.
Rhyland Klein01e73c82013-12-09 12:36:09 +010076 * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that
77 * is sent when we want to turn off CS at the end of a transaction.
Simon Glassa17d94f2013-02-25 14:08:39 -080078 */
79struct cros_ec_spi {
80 struct spi_device *spi;
81 s64 last_transfer_ns;
Alexandru M Stanff4378f2015-06-09 13:04:49 +020082 unsigned int start_of_msg_delay;
Rhyland Klein01e73c82013-12-09 12:36:09 +010083 unsigned int end_of_msg_delay;
Simon Glassa17d94f2013-02-25 14:08:39 -080084};
85
86static void debug_packet(struct device *dev, const char *name, u8 *ptr,
Stephen Barberd3654072015-06-09 13:04:46 +020087 int len)
Simon Glassa17d94f2013-02-25 14:08:39 -080088{
89#ifdef DEBUG
90 int i;
91
92 dev_dbg(dev, "%s: ", name);
93 for (i = 0; i < len; i++)
Thierry Reding9e146f42013-11-18 11:30:49 +010094 pr_cont(" %02x", ptr[i]);
95
96 pr_cont("\n");
Simon Glassa17d94f2013-02-25 14:08:39 -080097#endif
98}
99
Stephen Barberd3654072015-06-09 13:04:46 +0200100static int terminate_request(struct cros_ec_device *ec_dev)
101{
102 struct cros_ec_spi *ec_spi = ec_dev->priv;
103 struct spi_message msg;
104 struct spi_transfer trans;
105 int ret;
106
107 /*
108 * Turn off CS, possibly adding a delay to ensure the rising edge
109 * doesn't come too soon after the end of the data.
110 */
111 spi_message_init(&msg);
112 memset(&trans, 0, sizeof(trans));
113 trans.delay_usecs = ec_spi->end_of_msg_delay;
114 spi_message_add_tail(&trans, &msg);
115
116 ret = spi_sync(ec_spi->spi, &msg);
117
118 /* Reset end-of-response timer */
119 ec_spi->last_transfer_ns = ktime_get_ns();
120 if (ret < 0) {
121 dev_err(ec_dev->dev,
122 "cs-deassert spi transfer failed: %d\n",
123 ret);
124 }
125
126 return ret;
127}
128
129/**
130 * receive_n_bytes - receive n bytes from the EC.
131 *
132 * Assumes buf is a pointer into the ec_dev->din buffer
133 */
134static int receive_n_bytes(struct cros_ec_device *ec_dev, u8 *buf, int n)
135{
136 struct cros_ec_spi *ec_spi = ec_dev->priv;
137 struct spi_transfer trans;
138 struct spi_message msg;
139 int ret;
140
141 BUG_ON(buf - ec_dev->din + n > ec_dev->din_size);
142
143 memset(&trans, 0, sizeof(trans));
144 trans.cs_change = 1;
145 trans.rx_buf = buf;
146 trans.len = n;
147
148 spi_message_init(&msg);
149 spi_message_add_tail(&trans, &msg);
150 ret = spi_sync(ec_spi->spi, &msg);
151 if (ret < 0)
152 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
153
154 return ret;
155}
156
157/**
158 * cros_ec_spi_receive_packet - Receive a packet from the EC.
159 *
160 * This function has two phases: reading the preamble bytes (since if we read
161 * data from the EC before it is ready to send, we just get preamble) and
162 * reading the actual message.
163 *
164 * The received data is placed into ec_dev->din.
165 *
166 * @ec_dev: ChromeOS EC device
167 * @need_len: Number of message bytes we need to read
168 */
169static int cros_ec_spi_receive_packet(struct cros_ec_device *ec_dev,
170 int need_len)
171{
172 struct ec_host_response *response;
173 u8 *ptr, *end;
174 int ret;
175 unsigned long deadline;
176 int todo;
177
178 BUG_ON(EC_MSG_PREAMBLE_COUNT > ec_dev->din_size);
179
180 /* Receive data until we see the header byte */
181 deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
182 while (true) {
183 unsigned long start_jiffies = jiffies;
184
185 ret = receive_n_bytes(ec_dev,
186 ec_dev->din,
187 EC_MSG_PREAMBLE_COUNT);
188 if (ret < 0)
189 return ret;
190
191 ptr = ec_dev->din;
192 for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
193 if (*ptr == EC_SPI_FRAME_START) {
194 dev_dbg(ec_dev->dev, "msg found at %zd\n",
195 ptr - ec_dev->din);
196 break;
197 }
198 }
199 if (ptr != end)
200 break;
201
202 /*
203 * Use the time at the start of the loop as a timeout. This
204 * gives us one last shot at getting the transfer and is useful
205 * in case we got context switched out for a while.
206 */
207 if (time_after(start_jiffies, deadline)) {
208 dev_warn(ec_dev->dev, "EC failed to respond in time\n");
209 return -ETIMEDOUT;
210 }
211 }
212
213 /*
214 * ptr now points to the header byte. Copy any valid data to the
215 * start of our buffer
216 */
217 todo = end - ++ptr;
218 BUG_ON(todo < 0 || todo > ec_dev->din_size);
219 todo = min(todo, need_len);
220 memmove(ec_dev->din, ptr, todo);
221 ptr = ec_dev->din + todo;
222 dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
223 need_len, todo);
224 need_len -= todo;
225
226 /* If the entire response struct wasn't read, get the rest of it. */
227 if (todo < sizeof(*response)) {
228 ret = receive_n_bytes(ec_dev, ptr, sizeof(*response) - todo);
229 if (ret < 0)
230 return -EBADMSG;
231 ptr += (sizeof(*response) - todo);
232 todo = sizeof(*response);
233 }
234
235 response = (struct ec_host_response *)ec_dev->din;
236
237 /* Abort if data_len is too large. */
238 if (response->data_len > ec_dev->din_size)
239 return -EMSGSIZE;
240
241 /* Receive data until we have it all */
242 while (need_len > 0) {
243 /*
244 * We can't support transfers larger than the SPI FIFO size
245 * unless we have DMA. We don't have DMA on the ISP SPI ports
246 * for Exynos. We need a way of asking SPI driver for
247 * maximum-supported transfer size.
248 */
249 todo = min(need_len, 256);
250 dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
251 todo, need_len, ptr - ec_dev->din);
252
253 ret = receive_n_bytes(ec_dev, ptr, todo);
254 if (ret < 0)
255 return ret;
256
257 ptr += todo;
258 need_len -= todo;
259 }
260
261 dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
262
263 return 0;
264}
265
Simon Glassa17d94f2013-02-25 14:08:39 -0800266/**
267 * cros_ec_spi_receive_response - Receive a response from the EC.
268 *
269 * This function has two phases: reading the preamble bytes (since if we read
270 * data from the EC before it is ready to send, we just get preamble) and
271 * reading the actual message.
272 *
273 * The received data is placed into ec_dev->din.
274 *
275 * @ec_dev: ChromeOS EC device
276 * @need_len: Number of message bytes we need to read
277 */
278static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
279 int need_len)
280{
Simon Glassa17d94f2013-02-25 14:08:39 -0800281 u8 *ptr, *end;
282 int ret;
283 unsigned long deadline;
284 int todo;
285
Stephen Barberd3654072015-06-09 13:04:46 +0200286 BUG_ON(EC_MSG_PREAMBLE_COUNT > ec_dev->din_size);
287
Simon Glassa17d94f2013-02-25 14:08:39 -0800288 /* Receive data until we see the header byte */
289 deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
Doug Andersonc9a81d62014-04-30 10:44:06 -0700290 while (true) {
291 unsigned long start_jiffies = jiffies;
292
Stephen Barberd3654072015-06-09 13:04:46 +0200293 ret = receive_n_bytes(ec_dev,
294 ec_dev->din,
295 EC_MSG_PREAMBLE_COUNT);
296 if (ret < 0)
Simon Glassa17d94f2013-02-25 14:08:39 -0800297 return ret;
Simon Glassa17d94f2013-02-25 14:08:39 -0800298
Stephen Barberd3654072015-06-09 13:04:46 +0200299 ptr = ec_dev->din;
Simon Glassa17d94f2013-02-25 14:08:39 -0800300 for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
Stephen Barberd3654072015-06-09 13:04:46 +0200301 if (*ptr == EC_SPI_FRAME_START) {
Geert Uytterhoevenc34924b2013-05-08 23:37:45 +0200302 dev_dbg(ec_dev->dev, "msg found at %zd\n",
Simon Glassa17d94f2013-02-25 14:08:39 -0800303 ptr - ec_dev->din);
304 break;
305 }
306 }
Doug Andersonc9a81d62014-04-30 10:44:06 -0700307 if (ptr != end)
308 break;
Simon Glassa17d94f2013-02-25 14:08:39 -0800309
Doug Andersonc9a81d62014-04-30 10:44:06 -0700310 /*
311 * Use the time at the start of the loop as a timeout. This
312 * gives us one last shot at getting the transfer and is useful
313 * in case we got context switched out for a while.
314 */
315 if (time_after(start_jiffies, deadline)) {
Simon Glassa17d94f2013-02-25 14:08:39 -0800316 dev_warn(ec_dev->dev, "EC failed to respond in time\n");
317 return -ETIMEDOUT;
318 }
Doug Andersonc9a81d62014-04-30 10:44:06 -0700319 }
Simon Glassa17d94f2013-02-25 14:08:39 -0800320
321 /*
322 * ptr now points to the header byte. Copy any valid data to the
323 * start of our buffer
324 */
325 todo = end - ++ptr;
326 BUG_ON(todo < 0 || todo > ec_dev->din_size);
327 todo = min(todo, need_len);
328 memmove(ec_dev->din, ptr, todo);
329 ptr = ec_dev->din + todo;
330 dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
331 need_len, todo);
332 need_len -= todo;
333
334 /* Receive data until we have it all */
335 while (need_len > 0) {
336 /*
337 * We can't support transfers larger than the SPI FIFO size
338 * unless we have DMA. We don't have DMA on the ISP SPI ports
339 * for Exynos. We need a way of asking SPI driver for
340 * maximum-supported transfer size.
341 */
342 todo = min(need_len, 256);
Geert Uytterhoevenc34924b2013-05-08 23:37:45 +0200343 dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
Simon Glassa17d94f2013-02-25 14:08:39 -0800344 todo, need_len, ptr - ec_dev->din);
345
Stephen Barberd3654072015-06-09 13:04:46 +0200346 ret = receive_n_bytes(ec_dev, ptr, todo);
347 if (ret < 0)
Simon Glassa17d94f2013-02-25 14:08:39 -0800348 return ret;
Simon Glassa17d94f2013-02-25 14:08:39 -0800349
350 debug_packet(ec_dev->dev, "interim", ptr, todo);
351 ptr += todo;
352 need_len -= todo;
353 }
354
Geert Uytterhoevenc34924b2013-05-08 23:37:45 +0200355 dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
Simon Glassa17d94f2013-02-25 14:08:39 -0800356
357 return 0;
358}
359
360/**
Stephen Barberd3654072015-06-09 13:04:46 +0200361 * cros_ec_pkt_xfer_spi - Transfer a packet over SPI and receive the reply
362 *
363 * @ec_dev: ChromeOS EC device
364 * @ec_msg: Message to transfer
365 */
366static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
367 struct cros_ec_command *ec_msg)
368{
369 struct ec_host_request *request;
370 struct ec_host_response *response;
371 struct cros_ec_spi *ec_spi = ec_dev->priv;
Alexandru M Stanff4378f2015-06-09 13:04:49 +0200372 struct spi_transfer trans, trans_delay;
Stephen Barberd3654072015-06-09 13:04:46 +0200373 struct spi_message msg;
374 int i, len;
375 u8 *ptr;
376 u8 *rx_buf;
377 u8 sum;
378 int ret = 0, final_ret;
379
380 len = cros_ec_prepare_tx(ec_dev, ec_msg);
381 request = (struct ec_host_request *)ec_dev->dout;
382 dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
383
384 /* If it's too soon to do another transaction, wait */
385 if (ec_spi->last_transfer_ns) {
386 unsigned long delay; /* The delay completed so far */
387
388 delay = ktime_get_ns() - ec_spi->last_transfer_ns;
389 if (delay < EC_SPI_RECOVERY_TIME_NS)
390 ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
391 }
392
393 rx_buf = kzalloc(len, GFP_KERNEL);
394 if (!rx_buf) {
395 ret = -ENOMEM;
396 goto exit;
397 }
398
Alexandru M Stanff4378f2015-06-09 13:04:49 +0200399 /*
400 * Leave a gap between CS assertion and clocking of data to allow the
401 * EC time to wakeup.
402 */
403 spi_message_init(&msg);
404 if (ec_spi->start_of_msg_delay) {
405 memset(&trans_delay, 0, sizeof(trans_delay));
406 trans_delay.delay_usecs = ec_spi->start_of_msg_delay;
407 spi_message_add_tail(&trans_delay, &msg);
408 }
409
Stephen Barberd3654072015-06-09 13:04:46 +0200410 /* Transmit phase - send our message */
411 memset(&trans, 0, sizeof(trans));
412 trans.tx_buf = ec_dev->dout;
413 trans.rx_buf = rx_buf;
414 trans.len = len;
415 trans.cs_change = 1;
Stephen Barberd3654072015-06-09 13:04:46 +0200416 spi_message_add_tail(&trans, &msg);
417 ret = spi_sync(ec_spi->spi, &msg);
418
419 /* Get the response */
420 if (!ret) {
421 /* Verify that EC can process command */
422 for (i = 0; i < len; i++) {
423 switch (rx_buf[i]) {
424 case EC_SPI_PAST_END:
425 case EC_SPI_RX_BAD_DATA:
426 case EC_SPI_NOT_READY:
427 ret = -EAGAIN;
428 ec_msg->result = EC_RES_IN_PROGRESS;
429 default:
430 break;
431 }
432 if (ret)
433 break;
434 }
435 if (!ret)
436 ret = cros_ec_spi_receive_packet(ec_dev,
437 ec_msg->insize + sizeof(*response));
438 } else {
439 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
440 }
441
442 final_ret = terminate_request(ec_dev);
443 if (!ret)
444 ret = final_ret;
445 if (ret < 0)
446 goto exit;
447
448 ptr = ec_dev->din;
449
450 /* check response error code */
451 response = (struct ec_host_response *)ptr;
452 ec_msg->result = response->result;
453
454 ret = cros_ec_check_result(ec_dev, ec_msg);
455 if (ret)
456 goto exit;
457
458 len = response->data_len;
459 sum = 0;
460 if (len > ec_msg->insize) {
461 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
462 len, ec_msg->insize);
463 ret = -EMSGSIZE;
464 goto exit;
465 }
466
467 for (i = 0; i < sizeof(*response); i++)
468 sum += ptr[i];
469
470 /* copy response packet payload and compute checksum */
471 memcpy(ec_msg->data, ptr + sizeof(*response), len);
472 for (i = 0; i < len; i++)
473 sum += ec_msg->data[i];
474
475 if (sum) {
476 dev_err(ec_dev->dev,
477 "bad packet checksum, calculated %x\n",
478 sum);
479 ret = -EBADMSG;
480 goto exit;
481 }
482
483 ret = len;
484exit:
485 kfree(rx_buf);
486 if (ec_msg->command == EC_CMD_REBOOT_EC)
487 msleep(EC_REBOOT_DELAY_MS);
488
489 return ret;
490}
491
492/**
Bill Richardson7e6cb5b2014-06-18 11:14:00 -0700493 * cros_ec_cmd_xfer_spi - Transfer a message over SPI and receive the reply
Simon Glassa17d94f2013-02-25 14:08:39 -0800494 *
495 * @ec_dev: ChromeOS EC device
496 * @ec_msg: Message to transfer
497 */
Bill Richardson7e6cb5b2014-06-18 11:14:00 -0700498static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
Bill Richardson5d4773e2014-06-18 11:14:02 -0700499 struct cros_ec_command *ec_msg)
Simon Glassa17d94f2013-02-25 14:08:39 -0800500{
501 struct cros_ec_spi *ec_spi = ec_dev->priv;
502 struct spi_transfer trans;
503 struct spi_message msg;
504 int i, len;
505 u8 *ptr;
Stephen Barberd3654072015-06-09 13:04:46 +0200506 u8 *rx_buf;
Simon Glassa17d94f2013-02-25 14:08:39 -0800507 int sum;
508 int ret = 0, final_ret;
Simon Glassa17d94f2013-02-25 14:08:39 -0800509
510 len = cros_ec_prepare_tx(ec_dev, ec_msg);
511 dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
512
513 /* If it's too soon to do another transaction, wait */
514 if (ec_spi->last_transfer_ns) {
Simon Glassa17d94f2013-02-25 14:08:39 -0800515 unsigned long delay; /* The delay completed so far */
516
Thomas Gleixner154adc12014-07-16 21:04:41 +0000517 delay = ktime_get_ns() - ec_spi->last_transfer_ns;
Simon Glassa17d94f2013-02-25 14:08:39 -0800518 if (delay < EC_SPI_RECOVERY_TIME_NS)
David Hendricks1fe36862014-04-30 10:44:04 -0700519 ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
Simon Glassa17d94f2013-02-25 14:08:39 -0800520 }
521
Stephen Barberd3654072015-06-09 13:04:46 +0200522 rx_buf = kzalloc(len, GFP_KERNEL);
523 if (!rx_buf) {
524 ret = -ENOMEM;
525 goto exit;
526 }
527
Simon Glassa17d94f2013-02-25 14:08:39 -0800528 /* Transmit phase - send our message */
529 debug_packet(ec_dev->dev, "out", ec_dev->dout, len);
Thierry Redingdaf93d22013-12-09 12:36:10 +0100530 memset(&trans, 0, sizeof(trans));
Simon Glassa17d94f2013-02-25 14:08:39 -0800531 trans.tx_buf = ec_dev->dout;
Stephen Barberd3654072015-06-09 13:04:46 +0200532 trans.rx_buf = rx_buf;
Simon Glassa17d94f2013-02-25 14:08:39 -0800533 trans.len = len;
534 trans.cs_change = 1;
535 spi_message_init(&msg);
536 spi_message_add_tail(&trans, &msg);
537 ret = spi_sync(ec_spi->spi, &msg);
538
539 /* Get the response */
540 if (!ret) {
Stephen Barberd3654072015-06-09 13:04:46 +0200541 /* Verify that EC can process command */
542 for (i = 0; i < len; i++) {
543 switch (rx_buf[i]) {
544 case EC_SPI_PAST_END:
545 case EC_SPI_RX_BAD_DATA:
546 case EC_SPI_NOT_READY:
547 ret = -EAGAIN;
548 ec_msg->result = EC_RES_IN_PROGRESS;
549 default:
550 break;
551 }
552 if (ret)
553 break;
554 }
555 if (!ret)
556 ret = cros_ec_spi_receive_response(ec_dev,
557 ec_msg->insize + EC_MSG_TX_PROTO_BYTES);
Simon Glassa17d94f2013-02-25 14:08:39 -0800558 } else {
559 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
560 }
561
Stephen Barberd3654072015-06-09 13:04:46 +0200562 final_ret = terminate_request(ec_dev);
Simon Glassa17d94f2013-02-25 14:08:39 -0800563 if (!ret)
564 ret = final_ret;
Stephen Barberd3654072015-06-09 13:04:46 +0200565 if (ret < 0)
Doug Anderson362196e2014-04-30 10:44:05 -0700566 goto exit;
Simon Glassa17d94f2013-02-25 14:08:39 -0800567
Simon Glassa17d94f2013-02-25 14:08:39 -0800568 ptr = ec_dev->din;
Bill Richardson6db07b62014-06-18 11:14:05 -0700569
570 /* check response error code */
571 ec_msg->result = ptr[0];
572 ret = cros_ec_check_result(ec_dev, ec_msg);
573 if (ret)
Doug Anderson362196e2014-04-30 10:44:05 -0700574 goto exit;
Bill Richardson6db07b62014-06-18 11:14:05 -0700575
Simon Glassa17d94f2013-02-25 14:08:39 -0800576 len = ptr[1];
577 sum = ptr[0] + ptr[1];
Bill Richardson5d4773e2014-06-18 11:14:02 -0700578 if (len > ec_msg->insize) {
Simon Glassa17d94f2013-02-25 14:08:39 -0800579 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
Bill Richardson5d4773e2014-06-18 11:14:02 -0700580 len, ec_msg->insize);
Doug Anderson362196e2014-04-30 10:44:05 -0700581 ret = -ENOSPC;
582 goto exit;
Simon Glassa17d94f2013-02-25 14:08:39 -0800583 }
584
585 /* copy response packet payload and compute checksum */
586 for (i = 0; i < len; i++) {
587 sum += ptr[i + 2];
Bill Richardson5d4773e2014-06-18 11:14:02 -0700588 if (ec_msg->insize)
Javier Martinez Canillasa8411782015-06-09 13:04:42 +0200589 ec_msg->data[i] = ptr[i + 2];
Simon Glassa17d94f2013-02-25 14:08:39 -0800590 }
591 sum &= 0xff;
592
593 debug_packet(ec_dev->dev, "in", ptr, len + 3);
594
595 if (sum != ptr[len + 2]) {
596 dev_err(ec_dev->dev,
597 "bad packet checksum, expected %02x, got %02x\n",
598 sum, ptr[len + 2]);
Doug Anderson362196e2014-04-30 10:44:05 -0700599 ret = -EBADMSG;
600 goto exit;
Simon Glassa17d94f2013-02-25 14:08:39 -0800601 }
602
Bill Richardson12ebc8a2014-06-18 11:14:06 -0700603 ret = len;
Doug Anderson362196e2014-04-30 10:44:05 -0700604exit:
Stephen Barberd3654072015-06-09 13:04:46 +0200605 kfree(rx_buf);
Doug Anderson659e1422014-09-18 17:18:54 +0200606 if (ec_msg->command == EC_CMD_REBOOT_EC)
607 msleep(EC_REBOOT_DELAY_MS);
608
Doug Anderson362196e2014-04-30 10:44:05 -0700609 return ret;
Simon Glassa17d94f2013-02-25 14:08:39 -0800610}
611
Rhyland Klein01e73c82013-12-09 12:36:09 +0100612static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
613{
614 struct device_node *np = dev->of_node;
615 u32 val;
616 int ret;
617
Alexandru M Stanff4378f2015-06-09 13:04:49 +0200618 ret = of_property_read_u32(np, "google,cros-ec-spi-pre-delay", &val);
619 if (!ret)
620 ec_spi->start_of_msg_delay = val;
621
Rhyland Klein01e73c82013-12-09 12:36:09 +0100622 ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val);
623 if (!ret)
624 ec_spi->end_of_msg_delay = val;
625}
626
Thierry Reding9922b412013-11-25 13:22:30 +0100627static int cros_ec_spi_probe(struct spi_device *spi)
Simon Glassa17d94f2013-02-25 14:08:39 -0800628{
629 struct device *dev = &spi->dev;
630 struct cros_ec_device *ec_dev;
631 struct cros_ec_spi *ec_spi;
632 int err;
633
634 spi->bits_per_word = 8;
635 spi->mode = SPI_MODE_0;
636 err = spi_setup(spi);
637 if (err < 0)
638 return err;
639
640 ec_spi = devm_kzalloc(dev, sizeof(*ec_spi), GFP_KERNEL);
641 if (ec_spi == NULL)
642 return -ENOMEM;
643 ec_spi->spi = spi;
644 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
645 if (!ec_dev)
646 return -ENOMEM;
647
Rhyland Klein01e73c82013-12-09 12:36:09 +0100648 /* Check for any DT properties */
649 cros_ec_spi_dt_probe(ec_spi, dev);
650
Simon Glassa17d94f2013-02-25 14:08:39 -0800651 spi_set_drvdata(spi, ec_dev);
Simon Glassa17d94f2013-02-25 14:08:39 -0800652 ec_dev->dev = dev;
653 ec_dev->priv = ec_spi;
654 ec_dev->irq = spi->irq;
Bill Richardson7e6cb5b2014-06-18 11:14:00 -0700655 ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi;
Stephen Barberd3654072015-06-09 13:04:46 +0200656 ec_dev->pkt_xfer = cros_ec_pkt_xfer_spi;
Simon Glassa17d94f2013-02-25 14:08:39 -0800657 ec_dev->phys_name = dev_name(&ec_spi->spi->dev);
Stephen Barber2c7589a2015-06-09 13:04:45 +0200658 ec_dev->din_size = EC_MSG_PREAMBLE_COUNT +
659 sizeof(struct ec_host_response) +
660 sizeof(struct ec_response_get_protocol_info);
661 ec_dev->dout_size = sizeof(struct ec_host_request);
Simon Glassa17d94f2013-02-25 14:08:39 -0800662
Stephen Barberd3654072015-06-09 13:04:46 +0200663
Simon Glassa17d94f2013-02-25 14:08:39 -0800664 err = cros_ec_register(ec_dev);
665 if (err) {
666 dev_err(dev, "cannot register EC\n");
667 return err;
668 }
669
Prathyush Kfb504972014-06-16 14:12:23 -0700670 device_init_wakeup(&spi->dev, true);
671
Simon Glassa17d94f2013-02-25 14:08:39 -0800672 return 0;
673}
674
Thierry Reding9922b412013-11-25 13:22:30 +0100675static int cros_ec_spi_remove(struct spi_device *spi)
Simon Glassa17d94f2013-02-25 14:08:39 -0800676{
677 struct cros_ec_device *ec_dev;
678
679 ec_dev = spi_get_drvdata(spi);
680 cros_ec_remove(ec_dev);
681
682 return 0;
683}
684
685#ifdef CONFIG_PM_SLEEP
686static int cros_ec_spi_suspend(struct device *dev)
687{
688 struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
689
690 return cros_ec_suspend(ec_dev);
691}
692
693static int cros_ec_spi_resume(struct device *dev)
694{
695 struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
696
697 return cros_ec_resume(ec_dev);
698}
699#endif
700
701static SIMPLE_DEV_PM_OPS(cros_ec_spi_pm_ops, cros_ec_spi_suspend,
702 cros_ec_spi_resume);
703
704static const struct spi_device_id cros_ec_spi_id[] = {
705 { "cros-ec-spi", 0 },
706 { }
707};
708MODULE_DEVICE_TABLE(spi, cros_ec_spi_id);
709
710static struct spi_driver cros_ec_driver_spi = {
711 .driver = {
712 .name = "cros-ec-spi",
713 .owner = THIS_MODULE,
714 .pm = &cros_ec_spi_pm_ops,
715 },
Thierry Reding9922b412013-11-25 13:22:30 +0100716 .probe = cros_ec_spi_probe,
717 .remove = cros_ec_spi_remove,
Simon Glassa17d94f2013-02-25 14:08:39 -0800718 .id_table = cros_ec_spi_id,
719};
720
721module_spi_driver(cros_ec_driver_spi);
722
Thierry Redingea0f8b02013-12-09 11:05:38 +0100723MODULE_LICENSE("GPL v2");
Simon Glassa17d94f2013-02-25 14:08:39 -0800724MODULE_DESCRIPTION("ChromeOS EC multi function device (SPI)");