1 files changed, 613 insertions, 0 deletions
diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
new file mode 100644
index 000000000..469dfc7a4
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_lightbar.c
@@ -0,0 +1,613 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Expose the Chromebook Pixel lightbar to userspace
+//
+// Copyright (C) 2014 Google, Inc.
+
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/kobject.h>
+#include <linux/module.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+
+#define DRV_NAME "cros-ec-lightbar"
+
+/* Rate-limit the lightbar interface to prevent DoS. */
+static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
+
+/*
+ * Whether or not we have given userspace control of the lightbar.
+ * If this is true, we won't do anything during suspend/resume.
+ */
+static bool userspace_control;
+
+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;
+}
+
+static struct cros_ec_command *alloc_lightbar_cmd_msg(struct cros_ec_dev *ec)
+{
+	struct cros_ec_command *msg;
+	int len;
+
+	len = max(sizeof(struct ec_params_lightbar),
+		  sizeof(struct ec_response_lightbar));
+
+	msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
+	if (!msg)
+		return NULL;
+
+	msg->version = 0;
+	msg->command = EC_CMD_LIGHTBAR_CMD + ec->cmd_offset;
+	msg->outsize = sizeof(struct ec_params_lightbar);
+	msg->insize = sizeof(struct ec_response_lightbar);
+
+	return msg;
+}
+
+static int get_lightbar_version(struct cros_ec_dev *ec,
+				uint32_t *ver_ptr, uint32_t *flg_ptr)
+{
+	struct ec_params_lightbar *param;
+	struct ec_response_lightbar *resp;
+	struct cros_ec_command *msg;
+	int ret;
+
+	msg = alloc_lightbar_cmd_msg(ec);
+	if (!msg)
+		return 0;
+
+	param = (struct ec_params_lightbar *)msg->data;
+	param->cmd = LIGHTBAR_CMD_VERSION;
+	msg->outsize = sizeof(param->cmd);
+	msg->result = sizeof(resp->version);
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+	if (ret < 0 && ret != -EINVAL) {
+		ret = 0;
+		goto exit;
+	}
+
+	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;
+		ret = 1;
+		goto exit;
+
+	case EC_RES_SUCCESS:
+		resp = (struct ec_response_lightbar *)msg->data;
+
+		/* Future devices w/lightbars should implement this command */
+		if (ver_ptr)
+			*ver_ptr = resp->version.num;
+		if (flg_ptr)
+			*flg_ptr = resp->version.flags;
+		ret = 1;
+		goto exit;
+	}
+
+	/* Anything else (ie, EC_RES_INVALID_COMMAND) - no lightbar */
+	ret = 0;
+exit:
+	kfree(msg);
+	return ret;
+}
+
+static ssize_t version_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	uint32_t version = 0, flags = 0;
+	struct cros_ec_dev *ec = to_cros_ec_dev(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 cros_ec_command *msg;
+	int ret;
+	unsigned int val;
+	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
+
+	if (kstrtouint(buf, 0, &val))
+		return -EINVAL;
+
+	msg = alloc_lightbar_cmd_msg(ec);
+	if (!msg)
+		return -ENOMEM;
+
+	param = (struct ec_params_lightbar *)msg->data;
+	param->cmd = LIGHTBAR_CMD_SET_BRIGHTNESS;
+	param->set_brightness.num = val;
+	ret = lb_throttle();
+	if (ret)
+		goto exit;
+
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+	if (ret < 0)
+		goto exit;
+
+	ret = count;
+exit:
+	kfree(msg);
+	return ret;
+}
+
+
+/*
+ * 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 cros_ec_command *msg;
+	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
+	unsigned int val[4];
+	int ret, i = 0, j = 0, ok = 0;
+
+	msg = alloc_lightbar_cmd_msg(ec);
+	if (!msg)
+		return -ENOMEM;
+
+	do {
+		/* Skip any whitespace */
+		while (*buf && isspace(*buf))
+			buf++;
+
+		if (!*buf)
+			break;
+
+		ret = sscanf(buf, "%i", &val[i++]);
+		if (ret == 0)
+			goto exit;
+
+		if (i == 4) {
+			param = (struct ec_params_lightbar *)msg->data;
+			param->cmd = LIGHTBAR_CMD_SET_RGB;
+			param->set_rgb.led = val[0];
+			param->set_rgb.red = val[1];
+			param->set_rgb.green = val[2];
+			param->set_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)
+					goto exit;
+			}
+
+			ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+			if (ret < 0)
+				goto exit;
+
+			i = 0;
+			ok = 1;
+		}
+
+		/* Skip over the number we just read */
+		while (*buf && !isspace(*buf))
+			buf++;
+
+	} while (*buf);
+
+exit:
+	kfree(msg);
+	return (ok && i == 0) ? count : -EINVAL;
+}
+
+static char const *seqname[] = {
+	"ERROR", "S5", "S3", "S0", "S5S3", "S3S0",
+	"S0S3", "S3S5", "STOP", "RUN", "KONAMI",
+	"TAP", "PROGRAM",
+};
+
+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;
+	int ret;
+	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
+
+	msg = alloc_lightbar_cmd_msg(ec);
+	if (!msg)
+		return -ENOMEM;
+
+	param = (struct ec_params_lightbar *)msg->data;
+	param->cmd = LIGHTBAR_CMD_GET_SEQ;
+	ret = lb_throttle();
+	if (ret)
+		goto exit;
+
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+	if (ret < 0) {
+		ret = scnprintf(buf, PAGE_SIZE, "XFER / EC ERROR %d / %d\n",
+				ret, msg->result);
+		goto exit;
+	}
+
+	resp = (struct ec_response_lightbar *)msg->data;
+	if (resp->get_seq.num >= ARRAY_SIZE(seqname))
+		ret = scnprintf(buf, PAGE_SIZE, "%d\n", resp->get_seq.num);
+	else
+		ret = scnprintf(buf, PAGE_SIZE, "%s\n",
+				seqname[resp->get_seq.num]);
+
+exit:
+	kfree(msg);
+	return ret;
+}
+
+static int lb_send_empty_cmd(struct cros_ec_dev *ec, uint8_t cmd)
+{
+	struct ec_params_lightbar *param;
+	struct cros_ec_command *msg;
+	int ret;
+
+	msg = alloc_lightbar_cmd_msg(ec);
+	if (!msg)
+		return -ENOMEM;
+
+	param = (struct ec_params_lightbar *)msg->data;
+	param->cmd = cmd;
+
+	ret = lb_throttle();
+	if (ret)
+		goto error;
+
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+	if (ret < 0)
+		goto error;
+
+	ret = 0;
+error:
+	kfree(msg);
+
+	return ret;
+}
+
+static int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
+{
+	struct ec_params_lightbar *param;
+	struct cros_ec_command *msg;
+	int ret;
+
+	msg = alloc_lightbar_cmd_msg(ec);
+	if (!msg)
+		return -ENOMEM;
+
+	param = (struct ec_params_lightbar *)msg->data;
+
+	param->cmd = LIGHTBAR_CMD_MANUAL_SUSPEND_CTRL;
+	param->manual_suspend_ctrl.enable = enable;
+
+	ret = lb_throttle();
+	if (ret)
+		goto error;
+
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+	if (ret < 0)
+		goto error;
+
+	ret = 0;
+error:
+	kfree(msg);
+
+	return ret;
+}
+
+static ssize_t sequence_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct ec_params_lightbar *param;
+	struct cros_ec_command *msg;
+	unsigned int num;
+	int ret, len;
+	struct cros_ec_dev *ec = to_cros_ec_dev(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;
+	}
+
+	msg = alloc_lightbar_cmd_msg(ec);
+	if (!msg)
+		return -ENOMEM;
+
+	param = (struct ec_params_lightbar *)msg->data;
+	param->cmd = LIGHTBAR_CMD_SEQ;
+	param->seq.num = num;
+	ret = lb_throttle();
+	if (ret)
+		goto exit;
+
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+	if (ret < 0)
+		goto exit;
+
+	ret = count;
+exit:
+	kfree(msg);
+	return ret;
+}
+
+static ssize_t program_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	int extra_bytes, max_size, ret;
+	struct ec_params_lightbar *param;
+	struct cros_ec_command *msg;
+	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
+
+	/*
+	 * We might need to reject the program for size reasons. The EC
+	 * enforces a maximum program size, but we also don't want to try
+	 * and send a program that is too big for the protocol. In order
+	 * to ensure the latter, we also need to ensure we have extra bytes
+	 * to represent the rest of the packet.
+	 */
+	extra_bytes = sizeof(*param) - sizeof(param->set_program.data);
+	max_size = min(EC_LB_PROG_LEN, ec->ec_dev->max_request - extra_bytes);
+	if (count > max_size) {
+		dev_err(dev, "Program is %u bytes, too long to send (max: %u)",
+			(unsigned int)count, max_size);
+
+		return -EINVAL;
+	}
+
+	msg = alloc_lightbar_cmd_msg(ec);
+	if (!msg)
+		return -ENOMEM;
+
+	ret = lb_throttle();
+	if (ret)
+		goto exit;
+
+	dev_info(dev, "Copying %zu byte program to EC", count);
+
+	param = (struct ec_params_lightbar *)msg->data;
+	param->cmd = LIGHTBAR_CMD_SET_PROGRAM;
+
+	param->set_program.size = count;
+	memcpy(param->set_program.data, buf, count);
+
+	/*
+	 * We need to set the message size manually or else it will use
+	 * EC_LB_PROG_LEN. This might be too long, and the program
+	 * is unlikely to use all of the space.
+	 */
+	msg->outsize = count + extra_bytes;
+
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+	if (ret < 0)
+		goto exit;
+
+	ret = count;
+exit:
+	kfree(msg);
+
+	return ret;
+}
+
+static ssize_t userspace_control_show(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "%d\n", userspace_control);
+}
+
+static ssize_t userspace_control_store(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf,
+				       size_t count)
+{
+	bool enable;
+	int ret;
+
+	ret = strtobool(buf, &enable);
+	if (ret < 0)
+		return ret;
+
+	userspace_control = enable;
+
+	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 DEVICE_ATTR_WO(program);
+static DEVICE_ATTR_RW(userspace_control);
+
+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,
+	&dev_attr_program.attr,
+	&dev_attr_userspace_control.attr,
+	NULL,
+};
+
+static const struct attribute_group cros_ec_lightbar_attr_group = {
+	.name = "lightbar",
+	.attrs = __lb_cmds_attrs,
+};
+
+static int cros_ec_lightbar_probe(struct platform_device *pd)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
+	struct cros_ec_platform *pdata = dev_get_platdata(ec_dev->dev);
+	struct device *dev = &pd->dev;
+	int ret;
+
+	/*
+	 * Only instantiate the lightbar if the EC name is 'cros_ec'. Other EC
+	 * devices like 'cros_pd' doesn't have a lightbar.
+	 */
+	if (strcmp(pdata->ec_name, CROS_EC_DEV_NAME) != 0)
+		return -ENODEV;
+
+	/*
+	 * Ask then for the lightbar version, if it's 0 then the 'cros_ec'
+	 * doesn't have a lightbar.
+	 */
+	if (!get_lightbar_version(ec_dev, NULL, NULL))
+		return -ENODEV;
+
+	/* Take control of the lightbar from the EC. */
+	lb_manual_suspend_ctrl(ec_dev, 1);
+
+	ret = sysfs_create_group(&ec_dev->class_dev.kobj,
+				 &cros_ec_lightbar_attr_group);
+	if (ret < 0)
+		dev_err(dev, "failed to create %s attributes. err=%d\n",
+			cros_ec_lightbar_attr_group.name, ret);
+
+	return ret;
+}
+
+static int cros_ec_lightbar_remove(struct platform_device *pd)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
+
+	sysfs_remove_group(&ec_dev->class_dev.kobj,
+			   &cros_ec_lightbar_attr_group);
+
+	/* Let the EC take over the lightbar again. */
+	lb_manual_suspend_ctrl(ec_dev, 0);
+
+	return 0;
+}
+
+static int __maybe_unused cros_ec_lightbar_resume(struct device *dev)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
+
+	if (userspace_control)
+		return 0;
+
+	return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_RESUME);
+}
+
+static int __maybe_unused cros_ec_lightbar_suspend(struct device *dev)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
+
+	if (userspace_control)
+		return 0;
+
+	return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_SUSPEND);
+}
+
+static SIMPLE_DEV_PM_OPS(cros_ec_lightbar_pm_ops,
+			 cros_ec_lightbar_suspend, cros_ec_lightbar_resume);
+
+static struct platform_driver cros_ec_lightbar_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.pm = &cros_ec_lightbar_pm_ops,
+	},
+	.probe = cros_ec_lightbar_probe,
+	.remove = cros_ec_lightbar_remove,
+};
+
+module_platform_driver(cros_ec_lightbar_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Expose the Chromebook Pixel's lightbar to userspace");
+MODULE_ALIAS("platform:" DRV_NAME);