1 // SPDX-License-Identifier: GPL-2.0
2 // ChromeOS EC communication protocol helper functions
4 // Copyright (C) 2015 Google, Inc
6 #include <linux/delay.h>
7 #include <linux/device.h>
8 #include <linux/module.h>
9 #include <linux/platform_data/cros_ec_commands.h>
10 #include <linux/platform_data/cros_ec_proto.h>
11 #include <linux/slab.h>
12 #include <asm/unaligned.h>
14 #include "cros_ec_trace.h"
16 #define EC_COMMAND_RETRIES 50
18 static const int cros_ec_error_map[] = {
19 [EC_RES_INVALID_COMMAND] = -EOPNOTSUPP,
20 [EC_RES_ERROR] = -EIO,
21 [EC_RES_INVALID_PARAM] = -EINVAL,
22 [EC_RES_ACCESS_DENIED] = -EACCES,
23 [EC_RES_INVALID_RESPONSE] = -EPROTO,
24 [EC_RES_INVALID_VERSION] = -ENOPROTOOPT,
25 [EC_RES_INVALID_CHECKSUM] = -EBADMSG,
26 [EC_RES_IN_PROGRESS] = -EINPROGRESS,
27 [EC_RES_UNAVAILABLE] = -ENODATA,
28 [EC_RES_TIMEOUT] = -ETIMEDOUT,
29 [EC_RES_OVERFLOW] = -EOVERFLOW,
30 [EC_RES_INVALID_HEADER] = -EBADR,
31 [EC_RES_REQUEST_TRUNCATED] = -EBADR,
32 [EC_RES_RESPONSE_TOO_BIG] = -EFBIG,
33 [EC_RES_BUS_ERROR] = -EFAULT,
34 [EC_RES_BUSY] = -EBUSY,
35 [EC_RES_INVALID_HEADER_VERSION] = -EBADMSG,
36 [EC_RES_INVALID_HEADER_CRC] = -EBADMSG,
37 [EC_RES_INVALID_DATA_CRC] = -EBADMSG,
38 [EC_RES_DUP_UNAVAILABLE] = -ENODATA,
41 static int cros_ec_map_error(uint32_t result)
45 if (result != EC_RES_SUCCESS) {
46 if (result < ARRAY_SIZE(cros_ec_error_map) && cros_ec_error_map[result])
47 ret = cros_ec_error_map[result];
55 static int prepare_packet(struct cros_ec_device *ec_dev,
56 struct cros_ec_command *msg)
58 struct ec_host_request *request;
63 BUG_ON(ec_dev->proto_version != EC_HOST_REQUEST_VERSION);
64 BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size);
67 request = (struct ec_host_request *)out;
68 request->struct_version = EC_HOST_REQUEST_VERSION;
69 request->checksum = 0;
70 request->command = msg->command;
71 request->command_version = msg->version;
72 request->reserved = 0;
73 request->data_len = msg->outsize;
75 for (i = 0; i < sizeof(*request); i++)
78 /* Copy data and update checksum */
79 memcpy(out + sizeof(*request), msg->data, msg->outsize);
80 for (i = 0; i < msg->outsize; i++)
83 request->checksum = -csum;
85 return sizeof(*request) + msg->outsize;
88 static int send_command(struct cros_ec_device *ec_dev,
89 struct cros_ec_command *msg)
92 int (*xfer_fxn)(struct cros_ec_device *ec, struct cros_ec_command *msg);
94 if (ec_dev->proto_version > 2)
95 xfer_fxn = ec_dev->pkt_xfer;
97 xfer_fxn = ec_dev->cmd_xfer;
101 * This error can happen if a communication error happened and
102 * the EC is trying to use protocol v2, on an underlying
103 * communication mechanism that does not support v2.
105 dev_err_once(ec_dev->dev,
106 "missing EC transfer API, cannot send command\n");
110 trace_cros_ec_request_start(msg);
111 ret = (*xfer_fxn)(ec_dev, msg);
112 trace_cros_ec_request_done(msg, ret);
113 if (msg->result == EC_RES_IN_PROGRESS) {
115 struct cros_ec_command *status_msg;
116 struct ec_response_get_comms_status *status;
118 status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
123 status_msg->version = 0;
124 status_msg->command = EC_CMD_GET_COMMS_STATUS;
125 status_msg->insize = sizeof(*status);
126 status_msg->outsize = 0;
129 * Query the EC's status until it's no longer busy or
130 * we encounter an error.
132 for (i = 0; i < EC_COMMAND_RETRIES; i++) {
133 usleep_range(10000, 11000);
135 trace_cros_ec_request_start(status_msg);
136 ret = (*xfer_fxn)(ec_dev, status_msg);
137 trace_cros_ec_request_done(status_msg, ret);
143 msg->result = status_msg->result;
144 if (status_msg->result != EC_RES_SUCCESS)
147 status = (struct ec_response_get_comms_status *)
149 if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
160 * cros_ec_prepare_tx() - Prepare an outgoing message in the output buffer.
161 * @ec_dev: Device to register.
162 * @msg: Message to write.
164 * This is intended to be used by all ChromeOS EC drivers, but at present
165 * only SPI uses it. Once LPC uses the same protocol it can start using it.
166 * I2C could use it now, with a refactor of the existing code.
168 * Return: 0 on success or negative error code.
170 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
171 struct cros_ec_command *msg)
177 if (ec_dev->proto_version > 2)
178 return prepare_packet(ec_dev, msg);
180 BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
182 out[0] = EC_CMD_VERSION0 + msg->version;
183 out[1] = msg->command;
184 out[2] = msg->outsize;
185 csum = out[0] + out[1] + out[2];
186 for (i = 0; i < msg->outsize; i++)
187 csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
188 out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;
190 return EC_MSG_TX_PROTO_BYTES + msg->outsize;
192 EXPORT_SYMBOL(cros_ec_prepare_tx);
195 * cros_ec_check_result() - Check ec_msg->result.
196 * @ec_dev: EC device.
197 * @msg: Message to check.
199 * This is used by ChromeOS EC drivers to check the ec_msg->result for
200 * errors and to warn about them.
202 * Return: 0 on success or negative error code.
204 int cros_ec_check_result(struct cros_ec_device *ec_dev,
205 struct cros_ec_command *msg)
207 switch (msg->result) {
210 case EC_RES_IN_PROGRESS:
211 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
215 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
216 msg->command, msg->result);
220 EXPORT_SYMBOL(cros_ec_check_result);
223 * cros_ec_get_host_event_wake_mask
225 * Get the mask of host events that cause wake from suspend.
227 * @ec_dev: EC device to call
228 * @msg: message structure to use
229 * @mask: result when function returns >=0.
232 * the caller has ec_dev->lock mutex, or the caller knows there is
233 * no other command in progress.
235 static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev,
236 struct cros_ec_command *msg,
239 struct ec_response_host_event_mask *r;
242 msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK;
245 msg->insize = sizeof(*r);
247 ret = send_command(ec_dev, msg);
249 if (msg->result == EC_RES_INVALID_COMMAND)
251 if (msg->result != EC_RES_SUCCESS)
255 r = (struct ec_response_host_event_mask *)msg->data;
262 static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
264 struct cros_ec_command *msg)
267 * Try using v3+ to query for supported protocols. If this
268 * command fails, fall back to v2. Returns the highest protocol
269 * supported by the EC.
270 * Also sets the max request/response/passthru size.
274 if (!ec_dev->pkt_xfer)
275 return -EPROTONOSUPPORT;
277 memset(msg, 0, sizeof(*msg));
278 msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
279 msg->insize = sizeof(struct ec_response_get_protocol_info);
281 ret = send_command(ec_dev, msg);
285 "failed to check for EC[%d] protocol version: %d\n",
290 if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
292 else if (msg->result != EC_RES_SUCCESS)
298 static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
300 struct cros_ec_command *msg;
301 struct ec_params_hello *hello_params;
302 struct ec_response_hello *hello_response;
304 int len = max(sizeof(*hello_params), sizeof(*hello_response));
306 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
311 msg->command = EC_CMD_HELLO;
312 hello_params = (struct ec_params_hello *)msg->data;
313 msg->outsize = sizeof(*hello_params);
314 hello_response = (struct ec_response_hello *)msg->data;
315 msg->insize = sizeof(*hello_response);
317 hello_params->in_data = 0xa0b0c0d0;
319 ret = send_command(ec_dev, msg);
323 "EC failed to respond to v2 hello: %d\n",
326 } else if (msg->result != EC_RES_SUCCESS) {
328 "EC responded to v2 hello with error: %d\n",
332 } else if (hello_response->out_data != 0xa1b2c3d4) {
334 "EC responded to v2 hello with bad result: %u\n",
335 hello_response->out_data);
348 * cros_ec_get_host_command_version_mask
350 * Get the version mask of a given command.
352 * @ec_dev: EC device to call
353 * @msg: message structure to use
354 * @cmd: command to get the version of.
355 * @mask: result when function returns 0.
357 * @return 0 on success, error code otherwise
360 * the caller has ec_dev->lock mutex or the caller knows there is
361 * no other command in progress.
363 static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev,
366 struct ec_params_get_cmd_versions *pver;
367 struct ec_response_get_cmd_versions *rver;
368 struct cros_ec_command *msg;
371 msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)),
377 msg->command = EC_CMD_GET_CMD_VERSIONS;
378 msg->insize = sizeof(*rver);
379 msg->outsize = sizeof(*pver);
381 pver = (struct ec_params_get_cmd_versions *)msg->data;
384 ret = send_command(ec_dev, msg);
386 rver = (struct ec_response_get_cmd_versions *)msg->data;
387 *mask = rver->version_mask;
396 * cros_ec_query_all() - Query the protocol version supported by the
398 * @ec_dev: Device to register.
400 * Return: 0 on success or negative error code.
402 int cros_ec_query_all(struct cros_ec_device *ec_dev)
404 struct device *dev = ec_dev->dev;
405 struct cros_ec_command *proto_msg;
406 struct ec_response_get_protocol_info *proto_info;
410 proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
415 /* First try sending with proto v3. */
416 ec_dev->proto_version = 3;
417 ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg);
420 proto_info = (struct ec_response_get_protocol_info *)
422 ec_dev->max_request = proto_info->max_request_packet_size -
423 sizeof(struct ec_host_request);
424 ec_dev->max_response = proto_info->max_response_packet_size -
425 sizeof(struct ec_host_response);
426 ec_dev->proto_version =
427 min(EC_HOST_REQUEST_VERSION,
428 fls(proto_info->protocol_versions) - 1);
431 ec_dev->proto_version);
433 ec_dev->din_size = ec_dev->max_response +
434 sizeof(struct ec_host_response) +
435 EC_MAX_RESPONSE_OVERHEAD;
436 ec_dev->dout_size = ec_dev->max_request +
437 sizeof(struct ec_host_request) +
438 EC_MAX_REQUEST_OVERHEAD;
443 ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg);
446 dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
447 ec_dev->max_passthru = 0;
449 dev_dbg(ec_dev->dev, "found PD chip\n");
450 ec_dev->max_passthru =
451 proto_info->max_request_packet_size -
452 sizeof(struct ec_host_request);
455 /* Try querying with a v2 hello message. */
456 ec_dev->proto_version = 2;
457 ret = cros_ec_host_command_proto_query_v2(ec_dev);
460 /* V2 hello succeeded. */
461 dev_dbg(ec_dev->dev, "falling back to proto v2\n");
463 ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
464 ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
465 ec_dev->max_passthru = 0;
466 ec_dev->pkt_xfer = NULL;
467 ec_dev->din_size = EC_PROTO2_MSG_BYTES;
468 ec_dev->dout_size = EC_PROTO2_MSG_BYTES;
471 * It's possible for a test to occur too early when
472 * the EC isn't listening. If this happens, we'll
473 * test later when the first command is run.
475 ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
476 dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
481 devm_kfree(dev, ec_dev->din);
482 devm_kfree(dev, ec_dev->dout);
484 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
490 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
492 devm_kfree(dev, ec_dev->din);
497 /* Probe if MKBP event is supported */
498 ret = cros_ec_get_host_command_version_mask(ec_dev,
499 EC_CMD_GET_NEXT_EVENT,
501 if (ret < 0 || ver_mask == 0)
502 ec_dev->mkbp_event_supported = 0;
504 ec_dev->mkbp_event_supported = fls(ver_mask);
506 dev_dbg(ec_dev->dev, "MKBP support version %u\n",
507 ec_dev->mkbp_event_supported - 1);
509 /* Probe if host sleep v1 is supported for S0ix failure detection. */
510 ret = cros_ec_get_host_command_version_mask(ec_dev,
511 EC_CMD_HOST_SLEEP_EVENT,
513 ec_dev->host_sleep_v1 = (ret >= 0 && (ver_mask & EC_VER_MASK(1)));
515 /* Get host event wake mask. */
516 ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg,
517 &ec_dev->host_event_wake_mask);
520 * If the EC doesn't support EC_CMD_HOST_EVENT_GET_WAKE_MASK,
521 * use a reasonable default. Note that we ignore various
522 * battery, AC status, and power-state events, because (a)
523 * those can be quite common (e.g., when sitting at full
524 * charge, on AC) and (b) these are not actionable wake events;
525 * if anything, we'd like to continue suspending (to save
526 * power), not wake up.
528 ec_dev->host_event_wake_mask = U32_MAX &
529 ~(BIT(EC_HOST_EVENT_AC_DISCONNECTED) |
530 BIT(EC_HOST_EVENT_BATTERY_LOW) |
531 BIT(EC_HOST_EVENT_BATTERY_CRITICAL) |
532 BIT(EC_HOST_EVENT_PD_MCU) |
533 BIT(EC_HOST_EVENT_BATTERY_STATUS));
535 * Old ECs may not support this command. Complain about all
538 if (ret != -EOPNOTSUPP)
540 "failed to retrieve wake mask: %d\n", ret);
549 EXPORT_SYMBOL(cros_ec_query_all);
552 * cros_ec_cmd_xfer() - Send a command to the ChromeOS EC.
553 * @ec_dev: EC device.
554 * @msg: Message to write.
556 * Call this to send a command to the ChromeOS EC. This should be used
557 * instead of calling the EC's cmd_xfer() callback directly.
559 * Return: 0 on success or negative error code.
561 static int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
562 struct cros_ec_command *msg)
566 mutex_lock(&ec_dev->lock);
567 if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
568 ret = cros_ec_query_all(ec_dev);
571 "EC version unknown and query failed; aborting command\n");
572 mutex_unlock(&ec_dev->lock);
577 if (msg->insize > ec_dev->max_response) {
578 dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
579 msg->insize = ec_dev->max_response;
582 if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) {
583 if (msg->outsize > ec_dev->max_request) {
585 "request of size %u is too big (max: %u)\n",
587 ec_dev->max_request);
588 mutex_unlock(&ec_dev->lock);
592 if (msg->outsize > ec_dev->max_passthru) {
594 "passthru rq of size %u is too big (max: %u)\n",
596 ec_dev->max_passthru);
597 mutex_unlock(&ec_dev->lock);
601 ret = send_command(ec_dev, msg);
602 mutex_unlock(&ec_dev->lock);
608 * cros_ec_cmd_xfer_status() - Send a command to the ChromeOS EC.
609 * @ec_dev: EC device.
610 * @msg: Message to write.
612 * This function is identical to cros_ec_cmd_xfer, except it returns success
613 * status only if both the command was transmitted successfully and the EC
614 * replied with success status. It's not necessary to check msg->result when
615 * using this function.
618 * >=0 - The number of bytes transferred
619 * <0 - Linux error code
621 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
622 struct cros_ec_command *msg)
626 ret = cros_ec_cmd_xfer(ec_dev, msg);
628 dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
631 mapped = cros_ec_map_error(msg->result);
633 dev_dbg(ec_dev->dev, "Command result (err: %d [%d])\n",
634 msg->result, mapped);
639 EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
641 static int get_next_event_xfer(struct cros_ec_device *ec_dev,
642 struct cros_ec_command *msg,
643 struct ec_response_get_next_event_v1 *event,
644 int version, uint32_t size)
648 msg->version = version;
649 msg->command = EC_CMD_GET_NEXT_EVENT;
653 ret = cros_ec_cmd_xfer(ec_dev, msg);
655 ec_dev->event_size = ret - 1;
656 ec_dev->event_data = *event;
662 static int get_next_event(struct cros_ec_device *ec_dev)
665 struct cros_ec_command msg;
666 struct ec_response_get_next_event_v1 event;
668 struct cros_ec_command *msg = &buf.msg;
669 struct ec_response_get_next_event_v1 *event = &buf.event;
670 const int cmd_version = ec_dev->mkbp_event_supported - 1;
672 memset(msg, 0, sizeof(*msg));
673 if (ec_dev->suspended) {
674 dev_dbg(ec_dev->dev, "Device suspended.\n");
678 if (cmd_version == 0)
679 return get_next_event_xfer(ec_dev, msg, event, 0,
680 sizeof(struct ec_response_get_next_event));
682 return get_next_event_xfer(ec_dev, msg, event, cmd_version,
683 sizeof(struct ec_response_get_next_event_v1));
686 static int get_keyboard_state_event(struct cros_ec_device *ec_dev)
688 u8 buffer[sizeof(struct cros_ec_command) +
689 sizeof(ec_dev->event_data.data)];
690 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
693 msg->command = EC_CMD_MKBP_STATE;
694 msg->insize = sizeof(ec_dev->event_data.data);
697 ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg);
698 ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX;
699 memcpy(&ec_dev->event_data.data, msg->data,
700 sizeof(ec_dev->event_data.data));
702 return ec_dev->event_size;
706 * cros_ec_get_next_event() - Fetch next event from the ChromeOS EC.
707 * @ec_dev: Device to fetch event from.
708 * @wake_event: Pointer to a bool set to true upon return if the event might be
709 * treated as a wake event. Ignored if null.
710 * @has_more_events: Pointer to bool set to true if more than one event is
712 * Some EC will set this flag to indicate cros_ec_get_next_event()
713 * can be called multiple times in a row.
714 * It is an optimization to prevent issuing a EC command for
715 * nothing or wait for another interrupt from the EC to process
719 * Return: negative error code on errors; 0 for no data; or else number of
720 * bytes received (i.e., an event was retrieved successfully). Event types are
721 * written out to @ec_dev->event_data.event_type on success.
723 int cros_ec_get_next_event(struct cros_ec_device *ec_dev,
725 bool *has_more_events)
732 * Default value for wake_event.
733 * Wake up on keyboard event, wake up for spurious interrupt or link
740 * Default value for has_more_events.
741 * EC will raise another interrupt if AP does not process all events
745 *has_more_events = false;
747 if (!ec_dev->mkbp_event_supported)
748 return get_keyboard_state_event(ec_dev);
750 ret = get_next_event(ec_dev);
755 *has_more_events = ec_dev->event_data.event_type &
756 EC_MKBP_HAS_MORE_EVENTS;
757 ec_dev->event_data.event_type &= EC_MKBP_EVENT_TYPE_MASK;
760 event_type = ec_dev->event_data.event_type;
761 host_event = cros_ec_get_host_event(ec_dev);
764 * Sensor events need to be parsed by the sensor sub-device.
765 * Defer them, and don't report the wakeup here.
767 if (event_type == EC_MKBP_EVENT_SENSOR_FIFO)
769 /* Masked host-events should not count as wake events. */
770 else if (host_event &&
771 !(host_event & ec_dev->host_event_wake_mask))
777 EXPORT_SYMBOL(cros_ec_get_next_event);
780 * cros_ec_get_host_event() - Return a mask of event set by the ChromeOS EC.
781 * @ec_dev: Device to fetch event from.
783 * When MKBP is supported, when the EC raises an interrupt, we collect the
784 * events raised and call the functions in the ec notifier. This function
785 * is a helper to know which events are raised.
787 * Return: 0 on error or non-zero bitmask of one or more EC_HOST_EVENT_*.
789 u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev)
793 BUG_ON(!ec_dev->mkbp_event_supported);
795 if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT)
798 if (ec_dev->event_size != sizeof(host_event)) {
799 dev_warn(ec_dev->dev, "Invalid host event size\n");
803 host_event = get_unaligned_le32(&ec_dev->event_data.data.host_event);
807 EXPORT_SYMBOL(cros_ec_get_host_event);
810 * cros_ec_check_features() - Test for the presence of EC features
812 * @ec: EC device, does not have to be connected directly to the AP,
813 * can be daisy chained through another device.
814 * @feature: One of ec_feature_code bit.
816 * Call this function to test whether the ChromeOS EC supports a feature.
818 * Return: 1 if supported, 0 if not
820 int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
822 struct cros_ec_command *msg;
825 if (ec->features[0] == -1U && ec->features[1] == -1U) {
826 /* features bitmap not read yet */
827 msg = kzalloc(sizeof(*msg) + sizeof(ec->features), GFP_KERNEL);
831 msg->command = EC_CMD_GET_FEATURES + ec->cmd_offset;
832 msg->insize = sizeof(ec->features);
834 ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
836 dev_warn(ec->dev, "cannot get EC features: %d/%d\n",
838 memset(ec->features, 0, sizeof(ec->features));
840 memcpy(ec->features, msg->data, sizeof(ec->features));
843 dev_dbg(ec->dev, "EC features %08x %08x\n",
844 ec->features[0], ec->features[1]);
849 return ec->features[feature / 32] & EC_FEATURE_MASK_0(feature);
851 EXPORT_SYMBOL_GPL(cros_ec_check_features);
854 * cros_ec_get_sensor_count() - Return the number of MEMS sensors supported.
856 * @ec: EC device, does not have to be connected directly to the AP,
857 * can be daisy chained through another device.
858 * Return: < 0 in case of error.
860 int cros_ec_get_sensor_count(struct cros_ec_dev *ec)
863 * Issue a command to get the number of sensor reported.
864 * If not supported, check for legacy mode.
866 int ret, sensor_count;
867 struct ec_params_motion_sense *params;
868 struct ec_response_motion_sense *resp;
869 struct cros_ec_command *msg;
870 struct cros_ec_device *ec_dev = ec->ec_dev;
873 msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*resp)),
879 msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
880 msg->outsize = sizeof(*params);
881 msg->insize = sizeof(*resp);
883 params = (struct ec_params_motion_sense *)msg->data;
884 params->cmd = MOTIONSENSE_CMD_DUMP;
886 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
889 } else if (msg->result != EC_RES_SUCCESS) {
890 sensor_count = -EPROTO;
892 resp = (struct ec_response_motion_sense *)msg->data;
893 sensor_count = resp->dump.sensor_count;
898 * Check legacy mode: Let's find out if sensors are accessible
901 if (sensor_count == -EPROTO &&
902 ec->cmd_offset == 0 &&
903 ec_dev->cmd_readmem) {
904 ret = ec_dev->cmd_readmem(ec_dev, EC_MEMMAP_ACC_STATUS,
907 (status & EC_MEMMAP_ACC_STATUS_PRESENCE_BIT)) {
909 * We have 2 sensors, one in the lid, one in the base.
914 * EC uses LPC interface and no sensors are presented.
918 } else if (sensor_count == -EPROTO) {
919 /* EC responded, but does not understand DUMP command. */
924 EXPORT_SYMBOL_GPL(cros_ec_get_sensor_count);