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1/*
2 * cros_ec_lightbar - expose the Chromebook Pixel lightbar to userspace
3 *
4 * Copyright (C) 2014 Google, Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 */
19
20#define pr_fmt(fmt) "cros_ec_lightbar: " fmt
21
22#include <linux/ctype.h>
23#include <linux/delay.h>
24#include <linux/device.h>
25#include <linux/fs.h>
26#include <linux/kobject.h>
27#include <linux/mfd/cros_ec.h>
28#include <linux/mfd/cros_ec_commands.h>
29#include <linux/module.h>
30#include <linux/platform_device.h>
31#include <linux/sched.h>
32#include <linux/types.h>
33#include <linux/uaccess.h>
34#include <linux/slab.h>
35
36/* Rate-limit the lightbar interface to prevent DoS. */
37static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
38
39/*
40 * Whether or not we have given userspace control of the lightbar.
41 * If this is true, we won't do anything during suspend/resume.
42 */
43static bool userspace_control;
44static struct cros_ec_dev *ec_with_lightbar;
45
46static ssize_t interval_msec_show(struct device *dev,
47 struct device_attribute *attr, char *buf)
48{
49 unsigned long msec = lb_interval_jiffies * 1000 / HZ;
50
51 return scnprintf(buf, PAGE_SIZE, "%lu\n", msec);
52}
53
54static ssize_t interval_msec_store(struct device *dev,
55 struct device_attribute *attr,
56 const char *buf, size_t count)
57{
58 unsigned long msec;
59
60 if (kstrtoul(buf, 0, &msec))
61 return -EINVAL;
62
63 lb_interval_jiffies = msec * HZ / 1000;
64
65 return count;
66}
67
68static DEFINE_MUTEX(lb_mutex);
69/* Return 0 if able to throttle correctly, error otherwise */
70static int lb_throttle(void)
71{
72 static unsigned long last_access;
73 unsigned long now, next_timeslot;
74 long delay;
75 int ret = 0;
76
77 mutex_lock(&lb_mutex);
78
79 now = jiffies;
80 next_timeslot = last_access + lb_interval_jiffies;
81
82 if (time_before(now, next_timeslot)) {
83 delay = (long)(next_timeslot) - (long)now;
84 set_current_state(TASK_INTERRUPTIBLE);
85 if (schedule_timeout(delay) > 0) {
86 /* interrupted - just abort */
87 ret = -EINTR;
88 goto out;
89 }
90 now = jiffies;
91 }
92
93 last_access = now;
94out:
95 mutex_unlock(&lb_mutex);
96
97 return ret;
98}
99
100static struct cros_ec_command *alloc_lightbar_cmd_msg(struct cros_ec_dev *ec)
101{
102 struct cros_ec_command *msg;
103 int len;
104
105 len = max(sizeof(struct ec_params_lightbar),
106 sizeof(struct ec_response_lightbar));
107
108 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
109 if (!msg)
110 return NULL;
111
112 msg->version = 0;
113 msg->command = EC_CMD_LIGHTBAR_CMD + ec->cmd_offset;
114 msg->outsize = sizeof(struct ec_params_lightbar);
115 msg->insize = sizeof(struct ec_response_lightbar);
116
117 return msg;
118}
119
120static int get_lightbar_version(struct cros_ec_dev *ec,
121 uint32_t *ver_ptr, uint32_t *flg_ptr)
122{
123 struct ec_params_lightbar *param;
124 struct ec_response_lightbar *resp;
125 struct cros_ec_command *msg;
126 int ret;
127
128 msg = alloc_lightbar_cmd_msg(ec);
129 if (!msg)
130 return 0;
131
132 param = (struct ec_params_lightbar *)msg->data;
133 param->cmd = LIGHTBAR_CMD_VERSION;
134 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
135 if (ret < 0) {
136 ret = 0;
137 goto exit;
138 }
139
140 switch (msg->result) {
141 case EC_RES_INVALID_PARAM:
142 /* Pixel had no version command. */
143 if (ver_ptr)
144 *ver_ptr = 0;
145 if (flg_ptr)
146 *flg_ptr = 0;
147 ret = 1;
148 goto exit;
149
150 case EC_RES_SUCCESS:
151 resp = (struct ec_response_lightbar *)msg->data;
152
153 /* Future devices w/lightbars should implement this command */
154 if (ver_ptr)
155 *ver_ptr = resp->version.num;
156 if (flg_ptr)
157 *flg_ptr = resp->version.flags;
158 ret = 1;
159 goto exit;
160 }
161
162 /* Anything else (ie, EC_RES_INVALID_COMMAND) - no lightbar */
163 ret = 0;
164exit:
165 kfree(msg);
166 return ret;
167}
168
169static ssize_t version_show(struct device *dev,
170 struct device_attribute *attr, char *buf)
171{
172 uint32_t version = 0, flags = 0;
173 struct cros_ec_dev *ec = container_of(dev,
174 struct cros_ec_dev, class_dev);
175 int ret;
176
177 ret = lb_throttle();
178 if (ret)
179 return ret;
180
181 /* This should always succeed, because we check during init. */
182 if (!get_lightbar_version(ec, &version, &flags))
183 return -EIO;
184
185 return scnprintf(buf, PAGE_SIZE, "%d %d\n", version, flags);
186}
187
188static ssize_t brightness_store(struct device *dev,
189 struct device_attribute *attr,
190 const char *buf, size_t count)
191{
192 struct ec_params_lightbar *param;
193 struct cros_ec_command *msg;
194 int ret;
195 unsigned int val;
196 struct cros_ec_dev *ec = container_of(dev,
197 struct cros_ec_dev, class_dev);
198
199 if (kstrtouint(buf, 0, &val))
200 return -EINVAL;
201
202 msg = alloc_lightbar_cmd_msg(ec);
203 if (!msg)
204 return -ENOMEM;
205
206 param = (struct ec_params_lightbar *)msg->data;
207 param->cmd = LIGHTBAR_CMD_SET_BRIGHTNESS;
208 param->set_brightness.num = val;
209 ret = lb_throttle();
210 if (ret)
211 goto exit;
212
213 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
214 if (ret < 0)
215 goto exit;
216
217 if (msg->result != EC_RES_SUCCESS) {
218 ret = -EINVAL;
219 goto exit;
220 }
221
222 ret = count;
223exit:
224 kfree(msg);
225 return ret;
226}
227
228
229/*
230 * We expect numbers, and we'll keep reading until we find them, skipping over
231 * any whitespace (sysfs guarantees that the input is null-terminated). Every
232 * four numbers are sent to the lightbar as <LED,R,G,B>. We fail at the first
233 * parsing error, if we don't parse any numbers, or if we have numbers left
234 * over.
235 */
236static ssize_t led_rgb_store(struct device *dev, struct device_attribute *attr,
237 const char *buf, size_t count)
238{
239 struct ec_params_lightbar *param;
240 struct cros_ec_command *msg;
241 struct cros_ec_dev *ec = container_of(dev,
242 struct cros_ec_dev, class_dev);
243 unsigned int val[4];
244 int ret, i = 0, j = 0, ok = 0;
245
246 msg = alloc_lightbar_cmd_msg(ec);
247 if (!msg)
248 return -ENOMEM;
249
250 do {
251 /* Skip any whitespace */
252 while (*buf && isspace(*buf))
253 buf++;
254
255 if (!*buf)
256 break;
257
258 ret = sscanf(buf, "%i", &val[i++]);
259 if (ret == 0)
260 goto exit;
261
262 if (i == 4) {
263 param = (struct ec_params_lightbar *)msg->data;
264 param->cmd = LIGHTBAR_CMD_SET_RGB;
265 param->set_rgb.led = val[0];
266 param->set_rgb.red = val[1];
267 param->set_rgb.green = val[2];
268 param->set_rgb.blue = val[3];
269 /*
270 * Throttle only the first of every four transactions,
271 * so that the user can update all four LEDs at once.
272 */
273 if ((j++ % 4) == 0) {
274 ret = lb_throttle();
275 if (ret)
276 goto exit;
277 }
278
279 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
280 if (ret < 0)
281 goto exit;
282
283 if (msg->result != EC_RES_SUCCESS)
284 goto exit;
285
286 i = 0;
287 ok = 1;
288 }
289
290 /* Skip over the number we just read */
291 while (*buf && !isspace(*buf))
292 buf++;
293
294 } while (*buf);
295
296exit:
297 kfree(msg);
298 return (ok && i == 0) ? count : -EINVAL;
299}
300
301static char const *seqname[] = {
302 "ERROR", "S5", "S3", "S0", "S5S3", "S3S0",
303 "S0S3", "S3S5", "STOP", "RUN", "KONAMI",
304 "TAP", "PROGRAM",
305};
306
307static ssize_t sequence_show(struct device *dev,
308 struct device_attribute *attr, char *buf)
309{
310 struct ec_params_lightbar *param;
311 struct ec_response_lightbar *resp;
312 struct cros_ec_command *msg;
313 int ret;
314 struct cros_ec_dev *ec = container_of(dev,
315 struct cros_ec_dev, class_dev);
316
317 msg = alloc_lightbar_cmd_msg(ec);
318 if (!msg)
319 return -ENOMEM;
320
321 param = (struct ec_params_lightbar *)msg->data;
322 param->cmd = LIGHTBAR_CMD_GET_SEQ;
323 ret = lb_throttle();
324 if (ret)
325 goto exit;
326
327 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
328 if (ret < 0)
329 goto exit;
330
331 if (msg->result != EC_RES_SUCCESS) {
332 ret = scnprintf(buf, PAGE_SIZE,
333 "ERROR: EC returned %d\n", msg->result);
334 goto exit;
335 }
336
337 resp = (struct ec_response_lightbar *)msg->data;
338 if (resp->get_seq.num >= ARRAY_SIZE(seqname))
339 ret = scnprintf(buf, PAGE_SIZE, "%d\n", resp->get_seq.num);
340 else
341 ret = scnprintf(buf, PAGE_SIZE, "%s\n",
342 seqname[resp->get_seq.num]);
343
344exit:
345 kfree(msg);
346 return ret;
347}
348
349static int lb_send_empty_cmd(struct cros_ec_dev *ec, uint8_t cmd)
350{
351 struct ec_params_lightbar *param;
352 struct cros_ec_command *msg;
353 int ret;
354
355 msg = alloc_lightbar_cmd_msg(ec);
356 if (!msg)
357 return -ENOMEM;
358
359 param = (struct ec_params_lightbar *)msg->data;
360 param->cmd = cmd;
361
362 ret = lb_throttle();
363 if (ret)
364 goto error;
365
366 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
367 if (ret < 0)
368 goto error;
369 if (msg->result != EC_RES_SUCCESS) {
370 ret = -EINVAL;
371 goto error;
372 }
373 ret = 0;
374error:
375 kfree(msg);
376
377 return ret;
378}
379
380int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
381{
382 struct ec_params_lightbar *param;
383 struct cros_ec_command *msg;
384 int ret;
385
386 if (ec != ec_with_lightbar)
387 return 0;
388
389 msg = alloc_lightbar_cmd_msg(ec);
390 if (!msg)
391 return -ENOMEM;
392
393 param = (struct ec_params_lightbar *)msg->data;
394
395 param->cmd = LIGHTBAR_CMD_MANUAL_SUSPEND_CTRL;
396 param->manual_suspend_ctrl.enable = enable;
397
398 ret = lb_throttle();
399 if (ret)
400 goto error;
401
402 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
403 if (ret < 0)
404 goto error;
405 if (msg->result != EC_RES_SUCCESS) {
406 ret = -EINVAL;
407 goto error;
408 }
409 ret = 0;
410error:
411 kfree(msg);
412
413 return ret;
414}
415EXPORT_SYMBOL(lb_manual_suspend_ctrl);
416
417int lb_suspend(struct cros_ec_dev *ec)
418{
419 if (userspace_control || ec != ec_with_lightbar)
420 return 0;
421
422 return lb_send_empty_cmd(ec, LIGHTBAR_CMD_SUSPEND);
423}
424EXPORT_SYMBOL(lb_suspend);
425
426int lb_resume(struct cros_ec_dev *ec)
427{
428 if (userspace_control || ec != ec_with_lightbar)
429 return 0;
430
431 return lb_send_empty_cmd(ec, LIGHTBAR_CMD_RESUME);
432}
433EXPORT_SYMBOL(lb_resume);
434
435static ssize_t sequence_store(struct device *dev, struct device_attribute *attr,
436 const char *buf, size_t count)
437{
438 struct ec_params_lightbar *param;
439 struct cros_ec_command *msg;
440 unsigned int num;
441 int ret, len;
442 struct cros_ec_dev *ec = container_of(dev,
443 struct cros_ec_dev, class_dev);
444
445 for (len = 0; len < count; len++)
446 if (!isalnum(buf[len]))
447 break;
448
449 for (num = 0; num < ARRAY_SIZE(seqname); num++)
450 if (!strncasecmp(seqname[num], buf, len))
451 break;
452
453 if (num >= ARRAY_SIZE(seqname)) {
454 ret = kstrtouint(buf, 0, &num);
455 if (ret)
456 return ret;
457 }
458
459 msg = alloc_lightbar_cmd_msg(ec);
460 if (!msg)
461 return -ENOMEM;
462
463 param = (struct ec_params_lightbar *)msg->data;
464 param->cmd = LIGHTBAR_CMD_SEQ;
465 param->seq.num = num;
466 ret = lb_throttle();
467 if (ret)
468 goto exit;
469
470 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
471 if (ret < 0)
472 goto exit;
473
474 if (msg->result != EC_RES_SUCCESS) {
475 ret = -EINVAL;
476 goto exit;
477 }
478
479 ret = count;
480exit:
481 kfree(msg);
482 return ret;
483}
484
485static ssize_t program_store(struct device *dev, struct device_attribute *attr,
486 const char *buf, size_t count)
487{
488 int extra_bytes, max_size, ret;
489 struct ec_params_lightbar *param;
490 struct cros_ec_command *msg;
491 struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev,
492 class_dev);
493
494 /*
495 * We might need to reject the program for size reasons. The EC
496 * enforces a maximum program size, but we also don't want to try
497 * and send a program that is too big for the protocol. In order
498 * to ensure the latter, we also need to ensure we have extra bytes
499 * to represent the rest of the packet.
500 */
501 extra_bytes = sizeof(*param) - sizeof(param->set_program.data);
502 max_size = min(EC_LB_PROG_LEN, ec->ec_dev->max_request - extra_bytes);
503 if (count > max_size) {
504 dev_err(dev, "Program is %u bytes, too long to send (max: %u)",
505 (unsigned int)count, max_size);
506
507 return -EINVAL;
508 }
509
510 msg = alloc_lightbar_cmd_msg(ec);
511 if (!msg)
512 return -ENOMEM;
513
514 ret = lb_throttle();
515 if (ret)
516 goto exit;
517
518 dev_info(dev, "Copying %zu byte program to EC", count);
519
520 param = (struct ec_params_lightbar *)msg->data;
521 param->cmd = LIGHTBAR_CMD_SET_PROGRAM;
522
523 param->set_program.size = count;
524 memcpy(param->set_program.data, buf, count);
525
526 /*
527 * We need to set the message size manually or else it will use
528 * EC_LB_PROG_LEN. This might be too long, and the program
529 * is unlikely to use all of the space.
530 */
531 msg->outsize = count + extra_bytes;
532
533 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
534 if (ret < 0)
535 goto exit;
536 if (msg->result != EC_RES_SUCCESS) {
537 ret = -EINVAL;
538 goto exit;
539 }
540
541 ret = count;
542exit:
543 kfree(msg);
544
545 return ret;
546}
547
548static ssize_t userspace_control_show(struct device *dev,
549 struct device_attribute *attr,
550 char *buf)
551{
552 return scnprintf(buf, PAGE_SIZE, "%d\n", userspace_control);
553}
554
555static ssize_t userspace_control_store(struct device *dev,
556 struct device_attribute *attr,
557 const char *buf,
558 size_t count)
559{
560 bool enable;
561 int ret;
562
563 ret = strtobool(buf, &enable);
564 if (ret < 0)
565 return ret;
566
567 userspace_control = enable;
568
569 return count;
570}
571
572/* Module initialization */
573
574static DEVICE_ATTR_RW(interval_msec);
575static DEVICE_ATTR_RO(version);
576static DEVICE_ATTR_WO(brightness);
577static DEVICE_ATTR_WO(led_rgb);
578static DEVICE_ATTR_RW(sequence);
579static DEVICE_ATTR_WO(program);
580static DEVICE_ATTR_RW(userspace_control);
581
582static struct attribute *__lb_cmds_attrs[] = {
583 &dev_attr_interval_msec.attr,
584 &dev_attr_version.attr,
585 &dev_attr_brightness.attr,
586 &dev_attr_led_rgb.attr,
587 &dev_attr_sequence.attr,
588 &dev_attr_program.attr,
589 &dev_attr_userspace_control.attr,
590 NULL,
591};
592
593bool ec_has_lightbar(struct cros_ec_dev *ec)
594{
595 return !!get_lightbar_version(ec, NULL, NULL);
596}
597
598static umode_t cros_ec_lightbar_attrs_are_visible(struct kobject *kobj,
599 struct attribute *a, int n)
600{
601 struct device *dev = container_of(kobj, struct device, kobj);
602 struct cros_ec_dev *ec = container_of(dev,
603 struct cros_ec_dev, class_dev);
604 struct platform_device *pdev = to_platform_device(ec->dev);
605 struct cros_ec_platform *pdata = pdev->dev.platform_data;
606 int is_cros_ec;
607
608 is_cros_ec = strcmp(pdata->ec_name, CROS_EC_DEV_NAME);
609
610 if (is_cros_ec != 0)
611 return 0;
612
613 /* Only instantiate this stuff if the EC has a lightbar */
614 if (ec_has_lightbar(ec)) {
615 ec_with_lightbar = ec;
616 return a->mode;
617 }
618 return 0;
619}
620
621struct attribute_group cros_ec_lightbar_attr_group = {
622 .name = "lightbar",
623 .attrs = __lb_cmds_attrs,
624 .is_visible = cros_ec_lightbar_attrs_are_visible,
625};
626EXPORT_SYMBOL(cros_ec_lightbar_attr_group);