1 // SPDX-License-Identifier: GPL-2.0+
2 // Expose the Chromebook Pixel lightbar to userspace
4 // Copyright (C) 2014 Google, Inc.
6 #include <linux/ctype.h>
7 #include <linux/delay.h>
8 #include <linux/device.h>
10 #include <linux/kobject.h>
11 #include <linux/mfd/cros_ec.h>
12 #include <linux/mfd/cros_ec_commands.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15 #include <linux/sched.h>
16 #include <linux/types.h>
17 #include <linux/uaccess.h>
18 #include <linux/slab.h>
20 #define DRV_NAME "cros-ec-lightbar"
22 /* Rate-limit the lightbar interface to prevent DoS. */
23 static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
26 * Whether or not we have given userspace control of the lightbar.
27 * If this is true, we won't do anything during suspend/resume.
29 static bool userspace_control;
31 static ssize_t interval_msec_show(struct device *dev,
32 struct device_attribute *attr, char *buf)
34 unsigned long msec = lb_interval_jiffies * 1000 / HZ;
36 return scnprintf(buf, PAGE_SIZE, "%lu\n", msec);
39 static ssize_t interval_msec_store(struct device *dev,
40 struct device_attribute *attr,
41 const char *buf, size_t count)
45 if (kstrtoul(buf, 0, &msec))
48 lb_interval_jiffies = msec * HZ / 1000;
53 static DEFINE_MUTEX(lb_mutex);
54 /* Return 0 if able to throttle correctly, error otherwise */
55 static int lb_throttle(void)
57 static unsigned long last_access;
58 unsigned long now, next_timeslot;
62 mutex_lock(&lb_mutex);
65 next_timeslot = last_access + lb_interval_jiffies;
67 if (time_before(now, next_timeslot)) {
68 delay = (long)(next_timeslot) - (long)now;
69 set_current_state(TASK_INTERRUPTIBLE);
70 if (schedule_timeout(delay) > 0) {
71 /* interrupted - just abort */
80 mutex_unlock(&lb_mutex);
85 static struct cros_ec_command *alloc_lightbar_cmd_msg(struct cros_ec_dev *ec)
87 struct cros_ec_command *msg;
90 len = max(sizeof(struct ec_params_lightbar),
91 sizeof(struct ec_response_lightbar));
93 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
98 msg->command = EC_CMD_LIGHTBAR_CMD + ec->cmd_offset;
99 msg->outsize = sizeof(struct ec_params_lightbar);
100 msg->insize = sizeof(struct ec_response_lightbar);
105 static int get_lightbar_version(struct cros_ec_dev *ec,
106 uint32_t *ver_ptr, uint32_t *flg_ptr)
108 struct ec_params_lightbar *param;
109 struct ec_response_lightbar *resp;
110 struct cros_ec_command *msg;
113 msg = alloc_lightbar_cmd_msg(ec);
117 param = (struct ec_params_lightbar *)msg->data;
118 param->cmd = LIGHTBAR_CMD_VERSION;
119 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
125 switch (msg->result) {
126 case EC_RES_INVALID_PARAM:
127 /* Pixel had no version command. */
136 resp = (struct ec_response_lightbar *)msg->data;
138 /* Future devices w/lightbars should implement this command */
140 *ver_ptr = resp->version.num;
142 *flg_ptr = resp->version.flags;
147 /* Anything else (ie, EC_RES_INVALID_COMMAND) - no lightbar */
154 static ssize_t version_show(struct device *dev,
155 struct device_attribute *attr, char *buf)
157 uint32_t version = 0, flags = 0;
158 struct cros_ec_dev *ec = to_cros_ec_dev(dev);
165 /* This should always succeed, because we check during init. */
166 if (!get_lightbar_version(ec, &version, &flags))
169 return scnprintf(buf, PAGE_SIZE, "%d %d\n", version, flags);
172 static ssize_t brightness_store(struct device *dev,
173 struct device_attribute *attr,
174 const char *buf, size_t count)
176 struct ec_params_lightbar *param;
177 struct cros_ec_command *msg;
180 struct cros_ec_dev *ec = to_cros_ec_dev(dev);
182 if (kstrtouint(buf, 0, &val))
185 msg = alloc_lightbar_cmd_msg(ec);
189 param = (struct ec_params_lightbar *)msg->data;
190 param->cmd = LIGHTBAR_CMD_SET_BRIGHTNESS;
191 param->set_brightness.num = val;
196 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
200 if (msg->result != EC_RES_SUCCESS) {
213 * We expect numbers, and we'll keep reading until we find them, skipping over
214 * any whitespace (sysfs guarantees that the input is null-terminated). Every
215 * four numbers are sent to the lightbar as <LED,R,G,B>. We fail at the first
216 * parsing error, if we don't parse any numbers, or if we have numbers left
219 static ssize_t led_rgb_store(struct device *dev, struct device_attribute *attr,
220 const char *buf, size_t count)
222 struct ec_params_lightbar *param;
223 struct cros_ec_command *msg;
224 struct cros_ec_dev *ec = to_cros_ec_dev(dev);
226 int ret, i = 0, j = 0, ok = 0;
228 msg = alloc_lightbar_cmd_msg(ec);
233 /* Skip any whitespace */
234 while (*buf && isspace(*buf))
240 ret = sscanf(buf, "%i", &val[i++]);
245 param = (struct ec_params_lightbar *)msg->data;
246 param->cmd = LIGHTBAR_CMD_SET_RGB;
247 param->set_rgb.led = val[0];
248 param->set_rgb.red = val[1];
249 param->set_rgb.green = val[2];
250 param->set_rgb.blue = val[3];
252 * Throttle only the first of every four transactions,
253 * so that the user can update all four LEDs at once.
255 if ((j++ % 4) == 0) {
261 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
265 if (msg->result != EC_RES_SUCCESS)
272 /* Skip over the number we just read */
273 while (*buf && !isspace(*buf))
280 return (ok && i == 0) ? count : -EINVAL;
283 static char const *seqname[] = {
284 "ERROR", "S5", "S3", "S0", "S5S3", "S3S0",
285 "S0S3", "S3S5", "STOP", "RUN", "KONAMI",
289 static ssize_t sequence_show(struct device *dev,
290 struct device_attribute *attr, char *buf)
292 struct ec_params_lightbar *param;
293 struct ec_response_lightbar *resp;
294 struct cros_ec_command *msg;
296 struct cros_ec_dev *ec = to_cros_ec_dev(dev);
298 msg = alloc_lightbar_cmd_msg(ec);
302 param = (struct ec_params_lightbar *)msg->data;
303 param->cmd = LIGHTBAR_CMD_GET_SEQ;
308 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
312 if (msg->result != EC_RES_SUCCESS) {
313 ret = scnprintf(buf, PAGE_SIZE,
314 "ERROR: EC returned %d\n", msg->result);
318 resp = (struct ec_response_lightbar *)msg->data;
319 if (resp->get_seq.num >= ARRAY_SIZE(seqname))
320 ret = scnprintf(buf, PAGE_SIZE, "%d\n", resp->get_seq.num);
322 ret = scnprintf(buf, PAGE_SIZE, "%s\n",
323 seqname[resp->get_seq.num]);
330 static int lb_send_empty_cmd(struct cros_ec_dev *ec, uint8_t cmd)
332 struct ec_params_lightbar *param;
333 struct cros_ec_command *msg;
336 msg = alloc_lightbar_cmd_msg(ec);
340 param = (struct ec_params_lightbar *)msg->data;
347 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
350 if (msg->result != EC_RES_SUCCESS) {
361 static int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
363 struct ec_params_lightbar *param;
364 struct cros_ec_command *msg;
367 msg = alloc_lightbar_cmd_msg(ec);
371 param = (struct ec_params_lightbar *)msg->data;
373 param->cmd = LIGHTBAR_CMD_MANUAL_SUSPEND_CTRL;
374 param->manual_suspend_ctrl.enable = enable;
380 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
383 if (msg->result != EC_RES_SUCCESS) {
394 static ssize_t sequence_store(struct device *dev, struct device_attribute *attr,
395 const char *buf, size_t count)
397 struct ec_params_lightbar *param;
398 struct cros_ec_command *msg;
401 struct cros_ec_dev *ec = to_cros_ec_dev(dev);
403 for (len = 0; len < count; len++)
404 if (!isalnum(buf[len]))
407 for (num = 0; num < ARRAY_SIZE(seqname); num++)
408 if (!strncasecmp(seqname[num], buf, len))
411 if (num >= ARRAY_SIZE(seqname)) {
412 ret = kstrtouint(buf, 0, &num);
417 msg = alloc_lightbar_cmd_msg(ec);
421 param = (struct ec_params_lightbar *)msg->data;
422 param->cmd = LIGHTBAR_CMD_SEQ;
423 param->seq.num = num;
428 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
432 if (msg->result != EC_RES_SUCCESS) {
443 static ssize_t program_store(struct device *dev, struct device_attribute *attr,
444 const char *buf, size_t count)
446 int extra_bytes, max_size, ret;
447 struct ec_params_lightbar *param;
448 struct cros_ec_command *msg;
449 struct cros_ec_dev *ec = to_cros_ec_dev(dev);
452 * We might need to reject the program for size reasons. The EC
453 * enforces a maximum program size, but we also don't want to try
454 * and send a program that is too big for the protocol. In order
455 * to ensure the latter, we also need to ensure we have extra bytes
456 * to represent the rest of the packet.
458 extra_bytes = sizeof(*param) - sizeof(param->set_program.data);
459 max_size = min(EC_LB_PROG_LEN, ec->ec_dev->max_request - extra_bytes);
460 if (count > max_size) {
461 dev_err(dev, "Program is %u bytes, too long to send (max: %u)",
462 (unsigned int)count, max_size);
467 msg = alloc_lightbar_cmd_msg(ec);
475 dev_info(dev, "Copying %zu byte program to EC", count);
477 param = (struct ec_params_lightbar *)msg->data;
478 param->cmd = LIGHTBAR_CMD_SET_PROGRAM;
480 param->set_program.size = count;
481 memcpy(param->set_program.data, buf, count);
484 * We need to set the message size manually or else it will use
485 * EC_LB_PROG_LEN. This might be too long, and the program
486 * is unlikely to use all of the space.
488 msg->outsize = count + extra_bytes;
490 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
493 if (msg->result != EC_RES_SUCCESS) {
505 static ssize_t userspace_control_show(struct device *dev,
506 struct device_attribute *attr,
509 return scnprintf(buf, PAGE_SIZE, "%d\n", userspace_control);
512 static ssize_t userspace_control_store(struct device *dev,
513 struct device_attribute *attr,
520 ret = strtobool(buf, &enable);
524 userspace_control = enable;
529 /* Module initialization */
531 static DEVICE_ATTR_RW(interval_msec);
532 static DEVICE_ATTR_RO(version);
533 static DEVICE_ATTR_WO(brightness);
534 static DEVICE_ATTR_WO(led_rgb);
535 static DEVICE_ATTR_RW(sequence);
536 static DEVICE_ATTR_WO(program);
537 static DEVICE_ATTR_RW(userspace_control);
539 static struct attribute *__lb_cmds_attrs[] = {
540 &dev_attr_interval_msec.attr,
541 &dev_attr_version.attr,
542 &dev_attr_brightness.attr,
543 &dev_attr_led_rgb.attr,
544 &dev_attr_sequence.attr,
545 &dev_attr_program.attr,
546 &dev_attr_userspace_control.attr,
550 struct attribute_group cros_ec_lightbar_attr_group = {
552 .attrs = __lb_cmds_attrs,
555 static int cros_ec_lightbar_probe(struct platform_device *pd)
557 struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
558 struct cros_ec_platform *pdata = dev_get_platdata(ec_dev->dev);
559 struct device *dev = &pd->dev;
563 * Only instantiate the lightbar if the EC name is 'cros_ec'. Other EC
564 * devices like 'cros_pd' doesn't have a lightbar.
566 if (strcmp(pdata->ec_name, CROS_EC_DEV_NAME) != 0)
570 * Ask then for the lightbar version, if it's 0 then the 'cros_ec'
571 * doesn't have a lightbar.
573 if (!get_lightbar_version(ec_dev, NULL, NULL))
576 /* Take control of the lightbar from the EC. */
577 lb_manual_suspend_ctrl(ec_dev, 1);
579 ret = sysfs_create_group(&ec_dev->class_dev.kobj,
580 &cros_ec_lightbar_attr_group);
582 dev_err(dev, "failed to create %s attributes. err=%d\n",
583 cros_ec_lightbar_attr_group.name, ret);
588 static int cros_ec_lightbar_remove(struct platform_device *pd)
590 struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
592 sysfs_remove_group(&ec_dev->class_dev.kobj,
593 &cros_ec_lightbar_attr_group);
595 /* Let the EC take over the lightbar again. */
596 lb_manual_suspend_ctrl(ec_dev, 0);
601 static int __maybe_unused cros_ec_lightbar_resume(struct device *dev)
603 struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
605 if (userspace_control)
608 return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_RESUME);
611 static int __maybe_unused cros_ec_lightbar_suspend(struct device *dev)
613 struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
615 if (userspace_control)
618 return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_SUSPEND);
621 static SIMPLE_DEV_PM_OPS(cros_ec_lightbar_pm_ops,
622 cros_ec_lightbar_suspend, cros_ec_lightbar_resume);
624 static struct platform_driver cros_ec_lightbar_driver = {
627 .pm = &cros_ec_lightbar_pm_ops,
629 .probe = cros_ec_lightbar_probe,
630 .remove = cros_ec_lightbar_remove,
633 module_platform_driver(cros_ec_lightbar_driver);
635 MODULE_LICENSE("GPL");
636 MODULE_DESCRIPTION("Expose the Chromebook Pixel's lightbar to userspace");
637 MODULE_ALIAS("platform:" DRV_NAME);