[mirror_ubuntu-bionic-kernel.git] / drivers / platform / chrome / cros_ec_lightbar.c

/*
 * cros_ec_lightbar - expose the Chromebook Pixel lightbar to userspace
 *
 * Copyright (C) 2014 Google, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#define pr_fmt(fmt) "cros_ec_lightbar: " fmt

#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/kobject.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/uaccess.h>

#include "cros_ec_dev.h"

/* Rate-limit the lightbar interface to prevent DoS. */
static unsigned long lb_interval_jiffies = 50 * HZ / 1000;

static ssize_t interval_msec_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	unsigned long msec = lb_interval_jiffies * 1000 / HZ;

	return scnprintf(buf, PAGE_SIZE, "%lu\n", msec);
}

static ssize_t interval_msec_store(struct device *dev,
				   struct device_attribute *attr,
				   const char *buf, size_t count)
{
	unsigned long msec;

	if (kstrtoul(buf, 0, &msec))
		return -EINVAL;

	lb_interval_jiffies = msec * HZ / 1000;

	return count;
}

static DEFINE_MUTEX(lb_mutex);
/* Return 0 if able to throttle correctly, error otherwise */
static int lb_throttle(void)
{
	static unsigned long last_access;
	unsigned long now, next_timeslot;
	long delay;
	int ret = 0;

	mutex_lock(&lb_mutex);

	now = jiffies;
	next_timeslot = last_access + lb_interval_jiffies;

	if (time_before(now, next_timeslot)) {
		delay = (long)(next_timeslot) - (long)now;
		set_current_state(TASK_INTERRUPTIBLE);
		if (schedule_timeout(delay) > 0) {
			/* interrupted - just abort */
			ret = -EINTR;
			goto out;
		}
		now = jiffies;
	}

	last_access = now;
out:
	mutex_unlock(&lb_mutex);

	return ret;
}

#define INIT_MSG(P, R) { \
		.command = EC_CMD_LIGHTBAR_CMD, \
		.outsize = sizeof(*P), \
		.insize = sizeof(*R), \
	}

static int get_lightbar_version(struct cros_ec_device *ec,
				uint32_t *ver_ptr, uint32_t *flg_ptr)
{
	struct ec_params_lightbar *param;
	struct ec_response_lightbar *resp;
	struct cros_ec_command msg = INIT_MSG(param, resp);
	int ret;

	param = (struct ec_params_lightbar *)msg.outdata;
	param->cmd = LIGHTBAR_CMD_VERSION;
	ret = cros_ec_cmd_xfer(ec, &msg);
	if (ret < 0)
		return 0;

	switch (msg.result) {
	case EC_RES_INVALID_PARAM:
		/* Pixel had no version command. */
		if (ver_ptr)
			*ver_ptr = 0;
		if (flg_ptr)
			*flg_ptr = 0;
		return 1;

	case EC_RES_SUCCESS:
		resp = (struct ec_response_lightbar *)msg.indata;

		/* Future devices w/lightbars should implement this command */
		if (ver_ptr)
			*ver_ptr = resp->version.num;
		if (flg_ptr)
			*flg_ptr = resp->version.flags;
		return 1;
	}

	/* Anything else (ie, EC_RES_INVALID_COMMAND) - no lightbar */
	return 0;
}

static ssize_t version_show(struct device *dev,
			    struct device_attribute *attr, char *buf)
{
	uint32_t version, flags;
	struct cros_ec_device *ec = dev_get_drvdata(dev);
	int ret;

	ret = lb_throttle();
	if (ret)
		return ret;

	/* This should always succeed, because we check during init. */
	if (!get_lightbar_version(ec, &version, &flags))
		return -EIO;

	return scnprintf(buf, PAGE_SIZE, "%d %d\n", version, flags);
}

static ssize_t brightness_store(struct device *dev,
				struct device_attribute *attr,
				const char *buf, size_t count)
{
	struct ec_params_lightbar *param;
	struct ec_response_lightbar *resp;
	struct cros_ec_command msg = INIT_MSG(param, resp);
	int ret;
	unsigned int val;
	struct cros_ec_device *ec = dev_get_drvdata(dev);

	if (kstrtouint(buf, 0, &val))
		return -EINVAL;

	param = (struct ec_params_lightbar *)msg.outdata;
	param->cmd = LIGHTBAR_CMD_BRIGHTNESS;
	param->brightness.num = val;
	ret = lb_throttle();
	if (ret)
		return ret;

	ret = cros_ec_cmd_xfer(ec, &msg);
	if (ret < 0)
		return ret;

	if (msg.result != EC_RES_SUCCESS)
		return -EINVAL;

	return count;
}


/*
 * We expect numbers, and we'll keep reading until we find them, skipping over
 * any whitespace (sysfs guarantees that the input is null-terminated). Every
 * four numbers are sent to the lightbar as <LED,R,G,B>. We fail at the first
 * parsing error, if we don't parse any numbers, or if we have numbers left
 * over.
 */
static ssize_t led_rgb_store(struct device *dev, struct device_attribute *attr,
			     const char *buf, size_t count)
{
	struct ec_params_lightbar *param;
	struct ec_response_lightbar *resp;
	struct cros_ec_command msg = INIT_MSG(param, resp);
	struct cros_ec_device *ec = dev_get_drvdata(dev);
	unsigned int val[4];
	int ret, i = 0, j = 0, ok = 0;

	do {
		/* Skip any whitespace */
		while (*buf && isspace(*buf))
			buf++;

		if (!*buf)
			break;

		ret = sscanf(buf, "%i", &val[i++]);
		if (ret == 0)
			return -EINVAL;

		if (i == 4) {
			param = (struct ec_params_lightbar *)msg.outdata;
			param->cmd = LIGHTBAR_CMD_RGB;
			param->rgb.led = val[0];
			param->rgb.red = val[1];
			param->rgb.green = val[2];
			param->rgb.blue = val[3];
			/*
			 * Throttle only the first of every four transactions,
			 * so that the user can update all four LEDs at once.
			 */
			if ((j++ % 4) == 0) {
				ret = lb_throttle();
				if (ret)
					return ret;
			}

			ret = cros_ec_cmd_xfer(ec, &msg);
			if (ret < 0)
				return ret;

			if (msg.result != EC_RES_SUCCESS)
				return -EINVAL;

			i = 0;
			ok = 1;
		}

		/* Skip over the number we just read */
		while (*buf && !isspace(*buf))
			buf++;

	} while (*buf);

	return (ok && i == 0) ? count : -EINVAL;
}

static const char const *seqname[] = {
	"ERROR", "S5", "S3", "S0", "S5S3", "S3S0",
	"S0S3", "S3S5", "STOP", "RUN", "PULSE", "TEST", "KONAMI",
};

static ssize_t sequence_show(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	struct ec_params_lightbar *param;
	struct ec_response_lightbar *resp;
	struct cros_ec_command msg = INIT_MSG(param, resp);
	int ret;
	struct cros_ec_device *ec = dev_get_drvdata(dev);

	param = (struct ec_params_lightbar *)msg.outdata;
	param->cmd = LIGHTBAR_CMD_GET_SEQ;
	ret = lb_throttle();
	if (ret)
		return ret;

	ret = cros_ec_cmd_xfer(ec, &msg);
	if (ret < 0)
		return ret;

	if (msg.result != EC_RES_SUCCESS)
		return scnprintf(buf, PAGE_SIZE,
				 "ERROR: EC returned %d\n", msg.result);

	resp = (struct ec_response_lightbar *)msg.indata;
	if (resp->get_seq.num >= ARRAY_SIZE(seqname))
		return scnprintf(buf, PAGE_SIZE, "%d\n", resp->get_seq.num);
	else
		return scnprintf(buf, PAGE_SIZE, "%s\n",
				 seqname[resp->get_seq.num]);
}

static ssize_t sequence_store(struct device *dev, struct device_attribute *attr,
			      const char *buf, size_t count)
{
	struct ec_params_lightbar *param;
	struct ec_response_lightbar *resp;
	struct cros_ec_command msg = INIT_MSG(param, resp);
	unsigned int num;
	int ret, len;
	struct cros_ec_device *ec = dev_get_drvdata(dev);

	for (len = 0; len < count; len++)
		if (!isalnum(buf[len]))
			break;

	for (num = 0; num < ARRAY_SIZE(seqname); num++)
		if (!strncasecmp(seqname[num], buf, len))
			break;

	if (num >= ARRAY_SIZE(seqname)) {
		ret = kstrtouint(buf, 0, &num);
		if (ret)
			return ret;
	}

	param = (struct ec_params_lightbar *)msg.outdata;
	param->cmd = LIGHTBAR_CMD_SEQ;
	param->seq.num = num;
	ret = lb_throttle();
	if (ret)
		return ret;

	ret = cros_ec_cmd_xfer(ec, &msg);
	if (ret < 0)
		return ret;

	if (msg.result != EC_RES_SUCCESS)
		return -EINVAL;

	return count;
}

/* Module initialization */

static DEVICE_ATTR_RW(interval_msec);
static DEVICE_ATTR_RO(version);
static DEVICE_ATTR_WO(brightness);
static DEVICE_ATTR_WO(led_rgb);
static DEVICE_ATTR_RW(sequence);
static struct attribute *__lb_cmds_attrs[] = {
	&dev_attr_interval_msec.attr,
	&dev_attr_version.attr,
	&dev_attr_brightness.attr,
	&dev_attr_led_rgb.attr,
	&dev_attr_sequence.attr,
	NULL,
};
static struct attribute_group lb_cmds_attr_group = {
	.name = "lightbar",
	.attrs = __lb_cmds_attrs,
};

void ec_dev_lightbar_init(struct cros_ec_device *ec)
{
	int ret = 0;

	/* Only instantiate this stuff if the EC has a lightbar */
	if (!get_lightbar_version(ec, NULL, NULL))
		return;

	ret = sysfs_create_group(&ec->vdev->kobj, &lb_cmds_attr_group);
	if (ret)
		pr_warn("sysfs_create_group() failed: %d\n", ret);
}

void ec_dev_lightbar_remove(struct cros_ec_device *ec)
{
	sysfs_remove_group(&ec->vdev->kobj, &lb_cmds_attr_group);
}
Commit	Line	Data
f3f837e5 BR	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
	35	#include "cros_ec_dev.h"
	36
	37	/* Rate-limit the lightbar interface to prevent DoS. */
	38	static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
	39
	40	static ssize_t interval_msec_show(struct device *dev,
	41	struct device_attribute attr, char buf)
	42	{
	43	unsigned long msec = lb_interval_jiffies * 1000 / HZ;
	44
	45	return scnprintf(buf, PAGE_SIZE, "%lu\n", msec);
	46	}
	47
	48	static ssize_t interval_msec_store(struct device *dev,
	49	struct device_attribute *attr,
	50	const char *buf, size_t count)
	51	{
	52	unsigned long msec;
	53
	54	if (kstrtoul(buf, 0, &msec))
	55	return -EINVAL;
	56
	57	lb_interval_jiffies = msec * HZ / 1000;
	58
	59	return count;
	60	}
	61
	62	static DEFINE_MUTEX(lb_mutex);
	63	/* Return 0 if able to throttle correctly, error otherwise */
	64	static int lb_throttle(void)
65	{
66	static unsigned long last_access;
67	unsigned long now, next_timeslot;
68	long delay;
69	int ret = 0;
70
71	mutex_lock(&lb_mutex);
72
73	now = jiffies;
74	next_timeslot = last_access + lb_interval_jiffies;
75
76	if (time_before(now, next_timeslot)) {
77	delay = (long)(next_timeslot) - (long)now;
78	set_current_state(TASK_INTERRUPTIBLE);
79	if (schedule_timeout(delay) > 0) {
80	/* interrupted - just abort */
81	ret = -EINTR;
82	goto out;
83	}
84	now = jiffies;
85	}
86
87	last_access = now;
88	out:
89	mutex_unlock(&lb_mutex);
90
91	return ret;
92	}
93
94	#define INIT_MSG(P, R) { \
95	.command = EC_CMD_LIGHTBAR_CMD, \
96	.outsize = sizeof(*P), \
97	.insize = sizeof(*R), \
98	}
99
100	static int get_lightbar_version(struct cros_ec_device *ec,
101	uint32_t ver_ptr, uint32_t flg_ptr)
102	{
103	struct ec_params_lightbar *param;
104	struct ec_response_lightbar *resp;
105	struct cros_ec_command msg = INIT_MSG(param, resp);
106	int ret;
107
108	param = (struct ec_params_lightbar *)msg.outdata;
109	param->cmd = LIGHTBAR_CMD_VERSION;
110	ret = cros_ec_cmd_xfer(ec, &msg);
111	if (ret < 0)
112	return 0;
113
114	switch (msg.result) {
115	case EC_RES_INVALID_PARAM:
116	/* Pixel had no version command. */
117	if (ver_ptr)
118	*ver_ptr = 0;
119	if (flg_ptr)
120	*flg_ptr = 0;
121	return 1;
122
123	case EC_RES_SUCCESS:
124	resp = (struct ec_response_lightbar *)msg.indata;
125
126	/* Future devices w/lightbars should implement this command */
127	if (ver_ptr)
128	*ver_ptr = resp->version.num;
129	if (flg_ptr)
130	*flg_ptr = resp->version.flags;
131	return 1;
132	}
133
134	/* Anything else (ie, EC_RES_INVALID_COMMAND) - no lightbar */
135	return 0;
136	}
137
138	static ssize_t version_show(struct device *dev,
139	struct device_attribute attr, char buf)
140	{
141	uint32_t version, flags;
142	struct cros_ec_device *ec = dev_get_drvdata(dev);
143	int ret;
144
145	ret = lb_throttle();
146	if (ret)
147	return ret;
148
149	/* This should always succeed, because we check during init. */
150	if (!get_lightbar_version(ec, &version, &flags))
151	return -EIO;
152
153	return scnprintf(buf, PAGE_SIZE, "%d %d\n", version, flags);
154	}
155
156	static ssize_t brightness_store(struct device *dev,
157	struct device_attribute *attr,
158	const char *buf, size_t count)
159	{
160	struct ec_params_lightbar *param;
161	struct ec_response_lightbar *resp;
162	struct cros_ec_command msg = INIT_MSG(param, resp);
163	int ret;
164	unsigned int val;
165	struct cros_ec_device *ec = dev_get_drvdata(dev);
166
167	if (kstrtouint(buf, 0, &val))
168	return -EINVAL;
169
170	param = (struct ec_params_lightbar *)msg.outdata;
171	param->cmd = LIGHTBAR_CMD_BRIGHTNESS;
172	param->brightness.num = val;
173	ret = lb_throttle();
174	if (ret)
175	return ret;
176
177	ret = cros_ec_cmd_xfer(ec, &msg);
178	if (ret < 0)
179	return ret;
180
181	if (msg.result != EC_RES_SUCCESS)
182	return -EINVAL;
183
184	return count;
185	}
186
187
188	/*
189	* We expect numbers, and we'll keep reading until we find them, skipping over
190	* any whitespace (sysfs guarantees that the input is null-terminated). Every
191	* four numbers are sent to the lightbar as <LED,R,G,B>. We fail at the first
192	* parsing error, if we don't parse any numbers, or if we have numbers left
193	* over.
194	*/
195	static ssize_t led_rgb_store(struct device dev, struct device_attribute attr,
196	const char *buf, size_t count)
197	{
198	struct ec_params_lightbar *param;
199	struct ec_response_lightbar *resp;
200	struct cros_ec_command msg = INIT_MSG(param, resp);
201	struct cros_ec_device *ec = dev_get_drvdata(dev);
202	unsigned int val[4];
203	int ret, i = 0, j = 0, ok = 0;
204
205	do {
206	/* Skip any whitespace */
207	while (buf && isspace(buf))
208	buf++;
209
210	if (!*buf)
211	break;
212
213	ret = sscanf(buf, "%i", &val[i++]);
214	if (ret == 0)
215	return -EINVAL;
216
217	if (i == 4) {
218	param = (struct ec_params_lightbar *)msg.outdata;
219	param->cmd = LIGHTBAR_CMD_RGB;
220	param->rgb.led = val[0];
221	param->rgb.red = val[1];
222	param->rgb.green = val[2];
223	param->rgb.blue = val[3];
224	/*
225	* Throttle only the first of every four transactions,
226	* so that the user can update all four LEDs at once.
227	*/
228	if ((j++ % 4) == 0) {
229	ret = lb_throttle();
230	if (ret)
231	return ret;
232	}
233
234	ret = cros_ec_cmd_xfer(ec, &msg);
235	if (ret < 0)
236	return ret;
237
238	if (msg.result != EC_RES_SUCCESS)
239	return -EINVAL;
240
241	i = 0;
242	ok = 1;
243	}
244
245	/* Skip over the number we just read */
246	while (buf && !isspace(buf))
247	buf++;
248
249	} while (*buf);
250
251	return (ok && i == 0) ? count : -EINVAL;
252	}
253
254	static const char const *seqname[] = {
255	"ERROR", "S5", "S3", "S0", "S5S3", "S3S0",
256	"S0S3", "S3S5", "STOP", "RUN", "PULSE", "TEST", "KONAMI",
257	};
258
259	static ssize_t sequence_show(struct device *dev,
260	struct device_attribute attr, char buf)
261	{
262	struct ec_params_lightbar *param;
263	struct ec_response_lightbar *resp;
264	struct cros_ec_command msg = INIT_MSG(param, resp);
265	int ret;
266	struct cros_ec_device *ec = dev_get_drvdata(dev);
267
268	param = (struct ec_params_lightbar *)msg.outdata;
269	param->cmd = LIGHTBAR_CMD_GET_SEQ;
270	ret = lb_throttle();
271	if (ret)
272	return ret;
273
274	ret = cros_ec_cmd_xfer(ec, &msg);
275	if (ret < 0)
276	return ret;
277
278	if (msg.result != EC_RES_SUCCESS)
279	return scnprintf(buf, PAGE_SIZE,
280	"ERROR: EC returned %d\n", msg.result);
281
282	resp = (struct ec_response_lightbar *)msg.indata;
283	if (resp->get_seq.num >= ARRAY_SIZE(seqname))
284	return scnprintf(buf, PAGE_SIZE, "%d\n", resp->get_seq.num);
285	else
286	return scnprintf(buf, PAGE_SIZE, "%s\n",
287	seqname[resp->get_seq.num]);
288	}
289
290	static ssize_t sequence_store(struct device dev, struct device_attribute attr,
291	const char *buf, size_t count)
292	{
293	struct ec_params_lightbar *param;
294	struct ec_response_lightbar *resp;
295	struct cros_ec_command msg = INIT_MSG(param, resp);
296	unsigned int num;
297	int ret, len;
298	struct cros_ec_device *ec = dev_get_drvdata(dev);
299
300	for (len = 0; len < count; len++)
301	if (!isalnum(buf[len]))
302	break;
303
304	for (num = 0; num < ARRAY_SIZE(seqname); num++)
305	if (!strncasecmp(seqname[num], buf, len))
306	break;
307
308	if (num >= ARRAY_SIZE(seqname)) {
309	ret = kstrtouint(buf, 0, &num);
310	if (ret)
311	return ret;
312	}
313
314	param = (struct ec_params_lightbar *)msg.outdata;
315	param->cmd = LIGHTBAR_CMD_SEQ;
316	param->seq.num = num;
317	ret = lb_throttle();
318	if (ret)
319	return ret;
320
321	ret = cros_ec_cmd_xfer(ec, &msg);
322	if (ret < 0)
323	return ret;
324
325	if (msg.result != EC_RES_SUCCESS)
326	return -EINVAL;
327
328	return count;
329	}
330
331	/* Module initialization */
332
333	static DEVICE_ATTR_RW(interval_msec);
334	static DEVICE_ATTR_RO(version);
335	static DEVICE_ATTR_WO(brightness);
336	static DEVICE_ATTR_WO(led_rgb);
337	static DEVICE_ATTR_RW(sequence);
338	static struct attribute *__lb_cmds_attrs[] = {
339	&dev_attr_interval_msec.attr,
340	&dev_attr_version.attr,
341	&dev_attr_brightness.attr,
342	&dev_attr_led_rgb.attr,
343	&dev_attr_sequence.attr,
344	NULL,
345	};
346	static struct attribute_group lb_cmds_attr_group = {
347	.name = "lightbar",
348	.attrs = __lb_cmds_attrs,
349	};
350
351	void ec_dev_lightbar_init(struct cros_ec_device *ec)
352	{
353	int ret = 0;
354
355	/* Only instantiate this stuff if the EC has a lightbar */
356	if (!get_lightbar_version(ec, NULL, NULL))
357	return;
358
359	ret = sysfs_create_group(&ec->vdev->kobj, &lb_cmds_attr_group);
360	if (ret)
361	pr_warn("sysfs_create_group() failed: %d\n", ret);
362	}
363
364	void ec_dev_lightbar_remove(struct cros_ec_device *ec)
365	{
366	sysfs_remove_group(&ec->vdev->kobj, &lb_cmds_attr_group);
367	}