drivers/platform/chrome/cros_ec_lightbar.c - kernel/mindspeed - Git at Google

 /*
  * 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 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);
 }
	/*
	* 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 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);
	}