drivers/gpu/drm/drm_sysfs.c - kernel/msm-4.19 - Gitiles


 /*
  * drm_sysfs.c - Modifications to drm_sysfs_class.c to support
  *               extra sysfs attribute from DRM. Normal drm_sysfs_class
  *               does not allow adding attributes.
  *
  * Copyright (c) 2004 Jon Smirl <jonsmirl@gmail.com>
  * Copyright (c) 2003-2004 Greg Kroah-Hartman <greg@kroah.com>
  * Copyright (c) 2003-2004 IBM Corp.
  *
  * This file is released under the GPLv2
  *
  */

 #include <linux/device.h>
 #include <linux/kdev_t.h>
 #include <linux/gfp.h>
 #include <linux/err.h>
 #include <linux/export.h>

 #include <drm/drm_sysfs.h>
 #include <drm/drm_core.h>
 #include <drm/drmP.h>

 #define to_drm_minor(d) dev_get_drvdata(d)
 #define to_drm_connector(d) dev_get_drvdata(d)

 static struct device_type drm_sysfs_device_minor = {
 	.name = "drm_minor"
 };

 /**
  * __drm_class_suspend - internal DRM class suspend routine
  * @dev: Linux device to suspend
  * @state: power state to enter
  *
  * Just figures out what the actual struct drm_device associated with
  * @dev is and calls its suspend hook, if present.
  */
 static int __drm_class_suspend(struct device *dev, pm_message_t state)
 {
 	if (dev->type == &drm_sysfs_device_minor) {
 		struct drm_minor *drm_minor = to_drm_minor(dev);
 		struct drm_device *drm_dev = drm_minor->dev;

 		if (drm_minor->type == DRM_MINOR_LEGACY &&
 		    !drm_core_check_feature(drm_dev, DRIVER_MODESET) &&
 		    drm_dev->driver->suspend)
 			return drm_dev->driver->suspend(drm_dev, state);
 	}
 	return 0;
 }

 /**
  * drm_class_suspend - internal DRM class suspend hook. Simply calls
  * __drm_class_suspend() with the correct pm state.
  * @dev: Linux device to suspend
  */
 static int drm_class_suspend(struct device *dev)
 {
 	return __drm_class_suspend(dev, PMSG_SUSPEND);
 }

 /**
  * drm_class_freeze - internal DRM class freeze hook. Simply calls
  * __drm_class_suspend() with the correct pm state.
  * @dev: Linux device to freeze
  */
 static int drm_class_freeze(struct device *dev)
 {
 	return __drm_class_suspend(dev, PMSG_FREEZE);
 }

 /**
  * drm_class_resume - DRM class resume hook
  * @dev: Linux device to resume
  *
  * Just figures out what the actual struct drm_device associated with
  * @dev is and calls its resume hook, if present.
  */
 static int drm_class_resume(struct device *dev)
 {
 	if (dev->type == &drm_sysfs_device_minor) {
 		struct drm_minor *drm_minor = to_drm_minor(dev);
 		struct drm_device *drm_dev = drm_minor->dev;

 		if (drm_minor->type == DRM_MINOR_LEGACY &&
 		    !drm_core_check_feature(drm_dev, DRIVER_MODESET) &&
 		    drm_dev->driver->resume)
 			return drm_dev->driver->resume(drm_dev);
 	}
 	return 0;
 }

 static const struct dev_pm_ops drm_class_dev_pm_ops = {
 	.suspend	= drm_class_suspend,
 	.resume		= drm_class_resume,
 	.freeze		= drm_class_freeze,
 };

 static char *drm_devnode(struct device *dev, umode_t *mode)
 {
 	return kasprintf(GFP_KERNEL, "dri/%s", dev_name(dev));
 }

 static CLASS_ATTR_STRING(version, S_IRUGO,
 		CORE_NAME " "
 		__stringify(CORE_MAJOR) "."
 		__stringify(CORE_MINOR) "."
 		__stringify(CORE_PATCHLEVEL) " "
 		CORE_DATE);

 /**
  * drm_sysfs_create - create a struct drm_sysfs_class structure
  * @owner: pointer to the module that is to "own" this struct drm_sysfs_class
  * @name: pointer to a string for the name of this class.
  *
  * This is used to create DRM class pointer that can then be used
  * in calls to drm_sysfs_device_add().
  *
  * Note, the pointer created here is to be destroyed when finished by making a
  * call to drm_sysfs_destroy().
  */
 struct class *drm_sysfs_create(struct module *owner, char *name)
 {
 	struct class *class;
 	int err;

 	class = class_create(owner, name);
 	if (IS_ERR(class)) {
 		err = PTR_ERR(class);
 		goto err_out;
 	}

 	class->pm = &drm_class_dev_pm_ops;

 	err = class_create_file(class, &class_attr_version.attr);
 	if (err)
 		goto err_out_class;

 	class->devnode = drm_devnode;

 	return class;

 err_out_class:
 	class_destroy(class);
 err_out:
 	return ERR_PTR(err);
 }

 /**
  * drm_sysfs_destroy - destroys DRM class
  *
  * Destroy the DRM device class.
  */
 void drm_sysfs_destroy(void)
 {
 	if ((drm_class == NULL) || (IS_ERR(drm_class)))
 		return;
 	class_remove_file(drm_class, &class_attr_version.attr);
 	class_destroy(drm_class);
 	drm_class = NULL;
 }

 /*
  * Connector properties
  */
 static ssize_t status_show(struct device *device,
 			   struct device_attribute *attr,
 			   char *buf)
 {
 	struct drm_connector *connector = to_drm_connector(device);
 	enum drm_connector_status status;
 	int ret;

 	ret = mutex_lock_interruptible(&connector->dev->mode_config.mutex);
 	if (ret)
 		return ret;

 	status = connector->funcs->detect(connector, true);
 	mutex_unlock(&connector->dev->mode_config.mutex);

 	return snprintf(buf, PAGE_SIZE, "%s\n",
 			drm_get_connector_status_name(status));
 }

 static ssize_t dpms_show(struct device *device,
 			   struct device_attribute *attr,
 			   char *buf)
 {
 	struct drm_connector *connector = to_drm_connector(device);
 	struct drm_device *dev = connector->dev;
 	uint64_t dpms_status;
 	int ret;

 	ret = drm_object_property_get_value(&connector->base,
 					    dev->mode_config.dpms_property,
 					    &dpms_status);
 	if (ret)
 		return 0;

 	return snprintf(buf, PAGE_SIZE, "%s\n",
 			drm_get_dpms_name((int)dpms_status));
 }

 static ssize_t enabled_show(struct device *device,
 			    struct device_attribute *attr,
 			   char *buf)
 {
 	struct drm_connector *connector = to_drm_connector(device);

 	return snprintf(buf, PAGE_SIZE, "%s\n", connector->encoder ? "enabled" :
 			"disabled");
 }

 static ssize_t edid_show(struct file *filp, struct kobject *kobj,
 			 struct bin_attribute *attr, char *buf, loff_t off,
 			 size_t count)
 {
 	struct device *connector_dev = container_of(kobj, struct device, kobj);
 	struct drm_connector *connector = to_drm_connector(connector_dev);
 	unsigned char *edid;
 	size_t size;

 	if (!connector->edid_blob_ptr)
 		return 0;

 	edid = connector->edid_blob_ptr->data;
 	size = connector->edid_blob_ptr->length;
 	if (!edid)
 		return 0;

 	if (off >= size)
 		return 0;

 	if (off + count > size)
 		count = size - off;
 	memcpy(buf, edid + off, count);

 	return count;
 }

 static ssize_t modes_show(struct device *device,
 			   struct device_attribute *attr,
 			   char *buf)
 {
 	struct drm_connector *connector = to_drm_connector(device);
 	struct drm_display_mode *mode;
 	int written = 0;

 	list_for_each_entry(mode, &connector->modes, head) {
 		written += snprintf(buf + written, PAGE_SIZE - written, "%s\n",
 				    mode->name);
 	}

 	return written;
 }

 static ssize_t subconnector_show(struct device *device,
 			   struct device_attribute *attr,
 			   char *buf)
 {
 	struct drm_connector *connector = to_drm_connector(device);
 	struct drm_device *dev = connector->dev;
 	struct drm_property *prop = NULL;
 	uint64_t subconnector;
 	int is_tv = 0;
 	int ret;

 	switch (connector->connector_type) {
 		case DRM_MODE_CONNECTOR_DVII:
 			prop = dev->mode_config.dvi_i_subconnector_property;
 			break;
 		case DRM_MODE_CONNECTOR_Composite:
 		case DRM_MODE_CONNECTOR_SVIDEO:
 		case DRM_MODE_CONNECTOR_Component:
 		case DRM_MODE_CONNECTOR_TV:
 			prop = dev->mode_config.tv_subconnector_property;
 			is_tv = 1;
 			break;
 		default:
 			DRM_ERROR("Wrong connector type for this property\n");
 			return 0;
 	}

 	if (!prop) {
 		DRM_ERROR("Unable to find subconnector property\n");
 		return 0;
 	}

 	ret = drm_object_property_get_value(&connector->base, prop, &subconnector);
 	if (ret)
 		return 0;

 	return snprintf(buf, PAGE_SIZE, "%s", is_tv ?
 			drm_get_tv_subconnector_name((int)subconnector) :
 			drm_get_dvi_i_subconnector_name((int)subconnector));
 }

 static ssize_t select_subconnector_show(struct device *device,
 			   struct device_attribute *attr,
 			   char *buf)
 {
 	struct drm_connector *connector = to_drm_connector(device);
 	struct drm_device *dev = connector->dev;
 	struct drm_property *prop = NULL;
 	uint64_t subconnector;
 	int is_tv = 0;
 	int ret;

 	switch (connector->connector_type) {
 		case DRM_MODE_CONNECTOR_DVII:
 			prop = dev->mode_config.dvi_i_select_subconnector_property;
 			break;
 		case DRM_MODE_CONNECTOR_Composite:
 		case DRM_MODE_CONNECTOR_SVIDEO:
 		case DRM_MODE_CONNECTOR_Component:
 		case DRM_MODE_CONNECTOR_TV:
 			prop = dev->mode_config.tv_select_subconnector_property;
 			is_tv = 1;
 			break;
 		default:
 			DRM_ERROR("Wrong connector type for this property\n");
 			return 0;
 	}

 	if (!prop) {
 		DRM_ERROR("Unable to find select subconnector property\n");
 		return 0;
 	}

 	ret = drm_object_property_get_value(&connector->base, prop, &subconnector);
 	if (ret)
 		return 0;

 	return snprintf(buf, PAGE_SIZE, "%s", is_tv ?
 			drm_get_tv_select_name((int)subconnector) :
 			drm_get_dvi_i_select_name((int)subconnector));
 }

 static struct device_attribute connector_attrs[] = {
 	__ATTR_RO(status),
 	__ATTR_RO(enabled),
 	__ATTR_RO(dpms),
 	__ATTR_RO(modes),
 };

 /* These attributes are for both DVI-I connectors and all types of tv-out. */
 static struct device_attribute connector_attrs_opt1[] = {
 	__ATTR_RO(subconnector),
 	__ATTR_RO(select_subconnector),
 };

 static struct bin_attribute edid_attr = {
 	.attr.name = "edid",
 	.attr.mode = 0444,
 	.size = 0,
 	.read = edid_show,
 };

 /**
  * drm_sysfs_connector_add - add a connector to sysfs
  * @connector: connector to add
  *
  * Create a connector device in sysfs, along with its associated connector
  * properties (so far, connection status, dpms, mode list & edid) and
  * generate a hotplug event so userspace knows there's a new connector
  * available.
  */
 int drm_sysfs_connector_add(struct drm_connector *connector)
 {
 	struct drm_device *dev = connector->dev;
 	int attr_cnt = 0;
 	int opt_cnt = 0;
 	int i;
 	int ret;

 	if (connector->kdev)
 		return 0;

 	connector->kdev = device_create(drm_class, dev->primary->kdev,
 					0, connector, "card%d-%s",
 					dev->primary->index, drm_get_connector_name(connector));
 	DRM_DEBUG("adding \"%s\" to sysfs\n",
 		  drm_get_connector_name(connector));

 	if (IS_ERR(connector->kdev)) {
 		DRM_ERROR("failed to register connector device: %ld\n", PTR_ERR(connector->kdev));
 		ret = PTR_ERR(connector->kdev);
 		goto out;
 	}

 	/* Standard attributes */

 	for (attr_cnt = 0; attr_cnt < ARRAY_SIZE(connector_attrs); attr_cnt++) {
 		ret = device_create_file(connector->kdev, &connector_attrs[attr_cnt]);
 		if (ret)
 			goto err_out_files;
 	}

 	/* Optional attributes */
 	/*
 	 * In the long run it maybe a good idea to make one set of
 	 * optionals per connector type.
 	 */
 	switch (connector->connector_type) {
 		case DRM_MODE_CONNECTOR_DVII:
 		case DRM_MODE_CONNECTOR_Composite:
 		case DRM_MODE_CONNECTOR_SVIDEO:
 		case DRM_MODE_CONNECTOR_Component:
 		case DRM_MODE_CONNECTOR_TV:
 			for (opt_cnt = 0; opt_cnt < ARRAY_SIZE(connector_attrs_opt1); opt_cnt++) {
 				ret = device_create_file(connector->kdev, &connector_attrs_opt1[opt_cnt]);
 				if (ret)
 					goto err_out_files;
 			}
 			break;
 		default:
 			break;
 	}

 	ret = sysfs_create_bin_file(&connector->kdev->kobj, &edid_attr);
 	if (ret)
 		goto err_out_files;

 	/* Let userspace know we have a new connector */
 	drm_sysfs_hotplug_event(dev);

 	return 0;

 err_out_files:
 	for (i = 0; i < opt_cnt; i++)
 		device_remove_file(connector->kdev, &connector_attrs_opt1[i]);
 	for (i = 0; i < attr_cnt; i++)
 		device_remove_file(connector->kdev, &connector_attrs[i]);
 	device_unregister(connector->kdev);

 out:
 	return ret;
 }
 EXPORT_SYMBOL(drm_sysfs_connector_add);

 /**
  * drm_sysfs_connector_remove - remove an connector device from sysfs
  * @connector: connector to remove
  *
  * Remove @connector and its associated attributes from sysfs.  Note that
  * the device model core will take care of sending the "remove" uevent
  * at this time, so we don't need to do it.
  *
  * Note:
  * This routine should only be called if the connector was previously
  * successfully registered.  If @connector hasn't been registered yet,
  * you'll likely see a panic somewhere deep in sysfs code when called.
  */
 void drm_sysfs_connector_remove(struct drm_connector *connector)
 {
 	int i;

 	if (!connector->kdev)
 		return;
 	DRM_DEBUG("removing \"%s\" from sysfs\n",
 		  drm_get_connector_name(connector));

 	for (i = 0; i < ARRAY_SIZE(connector_attrs); i++)
 		device_remove_file(connector->kdev, &connector_attrs[i]);
 	sysfs_remove_bin_file(&connector->kdev->kobj, &edid_attr);
 	device_unregister(connector->kdev);
 	connector->kdev = NULL;
 }
 EXPORT_SYMBOL(drm_sysfs_connector_remove);

 /**
  * drm_sysfs_hotplug_event - generate a DRM uevent
  * @dev: DRM device
  *
  * Send a uevent for the DRM device specified by @dev.  Currently we only
  * set HOTPLUG=1 in the uevent environment, but this could be expanded to
  * deal with other types of events.
  */
 void drm_sysfs_hotplug_event(struct drm_device *dev)
 {
 	char *event_string = "HOTPLUG=1";
 	char *envp[] = { event_string, NULL };

 	DRM_DEBUG("generating hotplug event\n");

 	kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
 }
 EXPORT_SYMBOL(drm_sysfs_hotplug_event);

 /**
  * drm_sysfs_device_add - adds a class device to sysfs for a character driver
  * @dev: DRM device to be added
  * @head: DRM head in question
  *
  * Add a DRM device to the DRM's device model class.  We use @dev's PCI device
  * as the parent for the Linux device, and make sure it has a file containing
  * the driver we're using (for userspace compatibility).
  */
 int drm_sysfs_device_add(struct drm_minor *minor)
 {
 	char *minor_str;

 	if (minor->type == DRM_MINOR_CONTROL)
 		minor_str = "controlD%d";
         else if (minor->type == DRM_MINOR_RENDER)
                 minor_str = "renderD%d";
         else
                 minor_str = "card%d";

 	minor->kdev = device_create(drm_class, minor->dev->dev,
 				    MKDEV(DRM_MAJOR, minor->index),
 				    minor, minor_str, minor->index);
 	if (IS_ERR(minor->kdev)) {
 		DRM_ERROR("device create failed %ld\n", PTR_ERR(minor->kdev));
 		return PTR_ERR(minor->kdev);
 	}
 	return 0;
 }

 /**
  * drm_sysfs_device_remove - remove DRM device
  * @dev: DRM device to remove
  *
  * This call unregisters and cleans up a class device that was created with a
  * call to drm_sysfs_device_add()
  */
 void drm_sysfs_device_remove(struct drm_minor *minor)
 {
 	if (minor->kdev)
 		device_destroy(drm_class, MKDEV(DRM_MAJOR, minor->index));
 	minor->kdev = NULL;
 }


 /**
  * drm_class_device_register - Register a struct device in the drm class.
  *
  * @dev: pointer to struct device to register.
  *
  * @dev should have all relevant members pre-filled with the exception
  * of the class member. In particular, the device_type member must
  * be set.
  */

 int drm_class_device_register(struct device *dev)
 {
 	if (!drm_class || IS_ERR(drm_class))
 		return -ENOENT;

 	dev->class = drm_class;
 	return device_register(dev);
 }
 EXPORT_SYMBOL_GPL(drm_class_device_register);

 void drm_class_device_unregister(struct device *dev)
 {
 	return device_unregister(dev);
 }
 EXPORT_SYMBOL_GPL(drm_class_device_unregister);

	/*
	* drm_sysfs.c - Modifications to drm_sysfs_class.c to support
	* extra sysfs attribute from DRM. Normal drm_sysfs_class
	* does not allow adding attributes.
	*
	* Copyright (c) 2004 Jon Smirl <jonsmirl@gmail.com>
	* Copyright (c) 2003-2004 Greg Kroah-Hartman <greg@kroah.com>
	* Copyright (c) 2003-2004 IBM Corp.
	*
	* This file is released under the GPLv2
	*
	*/

	#include <linux/device.h>
	#include <linux/kdev_t.h>
	#include <linux/gfp.h>
	#include <linux/err.h>
	#include <linux/export.h>

	#include <drm/drm_sysfs.h>
	#include <drm/drm_core.h>
	#include <drm/drmP.h>

	#define to_drm_minor(d) dev_get_drvdata(d)
	#define to_drm_connector(d) dev_get_drvdata(d)

	static struct device_type drm_sysfs_device_minor = {
	.name = "drm_minor"
	};

	/**
	* __drm_class_suspend - internal DRM class suspend routine
	* @dev: Linux device to suspend
	* @state: power state to enter
	*
	* Just figures out what the actual struct drm_device associated with
	* @dev is and calls its suspend hook, if present.
	*/
	static int __drm_class_suspend(struct device *dev, pm_message_t state)
	{
	if (dev->type == &drm_sysfs_device_minor) {
	struct drm_minor *drm_minor = to_drm_minor(dev);
	struct drm_device *drm_dev = drm_minor->dev;

	if (drm_minor->type == DRM_MINOR_LEGACY &&
	!drm_core_check_feature(drm_dev, DRIVER_MODESET) &&
	drm_dev->driver->suspend)
	return drm_dev->driver->suspend(drm_dev, state);
	}
	return 0;
	}

	/**
	* drm_class_suspend - internal DRM class suspend hook. Simply calls
	* __drm_class_suspend() with the correct pm state.
	* @dev: Linux device to suspend
	*/
	static int drm_class_suspend(struct device *dev)
	{
	return __drm_class_suspend(dev, PMSG_SUSPEND);
	}

	/**
	* drm_class_freeze - internal DRM class freeze hook. Simply calls
	* __drm_class_suspend() with the correct pm state.
	* @dev: Linux device to freeze
	*/
	static int drm_class_freeze(struct device *dev)
	{
	return __drm_class_suspend(dev, PMSG_FREEZE);
	}

	/**
	* drm_class_resume - DRM class resume hook
	* @dev: Linux device to resume
	*
	* Just figures out what the actual struct drm_device associated with
	* @dev is and calls its resume hook, if present.
	*/
	static int drm_class_resume(struct device *dev)
	{
	if (dev->type == &drm_sysfs_device_minor) {
	struct drm_minor *drm_minor = to_drm_minor(dev);
	struct drm_device *drm_dev = drm_minor->dev;

	if (drm_minor->type == DRM_MINOR_LEGACY &&
	!drm_core_check_feature(drm_dev, DRIVER_MODESET) &&
	drm_dev->driver->resume)
	return drm_dev->driver->resume(drm_dev);
	}
	return 0;
	}

	static const struct dev_pm_ops drm_class_dev_pm_ops = {
	.suspend = drm_class_suspend,
	.resume = drm_class_resume,
	.freeze = drm_class_freeze,
	};

	static char drm_devnode(struct device dev, umode_t *mode)
	{
	return kasprintf(GFP_KERNEL, "dri/%s", dev_name(dev));
	}

	static CLASS_ATTR_STRING(version, S_IRUGO,
	CORE_NAME " "
	__stringify(CORE_MAJOR) "."
	__stringify(CORE_MINOR) "."
	__stringify(CORE_PATCHLEVEL) " "
	CORE_DATE);

	/**
	* drm_sysfs_create - create a struct drm_sysfs_class structure
	* @owner: pointer to the module that is to "own" this struct drm_sysfs_class
	* @name: pointer to a string for the name of this class.
	*
	* This is used to create DRM class pointer that can then be used
	* in calls to drm_sysfs_device_add().
	*
	* Note, the pointer created here is to be destroyed when finished by making a
	* call to drm_sysfs_destroy().
	*/
	struct class drm_sysfs_create(struct module owner, char *name)
	{
	struct class *class;
	int err;

	class = class_create(owner, name);
	if (IS_ERR(class)) {
	err = PTR_ERR(class);
	goto err_out;
	}

	class->pm = &drm_class_dev_pm_ops;

	err = class_create_file(class, &class_attr_version.attr);
	if (err)
	goto err_out_class;

	class->devnode = drm_devnode;

	return class;

	err_out_class:
	class_destroy(class);
	err_out:
	return ERR_PTR(err);
	}

	/**
	* drm_sysfs_destroy - destroys DRM class
	*
	* Destroy the DRM device class.
	*/
	void drm_sysfs_destroy(void)
	{
	if ((drm_class == NULL) \|\| (IS_ERR(drm_class)))
	return;
	class_remove_file(drm_class, &class_attr_version.attr);
	class_destroy(drm_class);
	drm_class = NULL;
	}

	/*
	* Connector properties
	*/
	static ssize_t status_show(struct device *device,
	struct device_attribute *attr,
	char *buf)
	{
	struct drm_connector *connector = to_drm_connector(device);
	enum drm_connector_status status;
	int ret;

	ret = mutex_lock_interruptible(&connector->dev->mode_config.mutex);
	if (ret)
	return ret;

	status = connector->funcs->detect(connector, true);
	mutex_unlock(&connector->dev->mode_config.mutex);

	return snprintf(buf, PAGE_SIZE, "%s\n",
	drm_get_connector_status_name(status));
	}

	static ssize_t dpms_show(struct device *device,
	struct device_attribute *attr,
	char *buf)
	{
	struct drm_connector *connector = to_drm_connector(device);
	struct drm_device *dev = connector->dev;
	uint64_t dpms_status;
	int ret;

	ret = drm_object_property_get_value(&connector->base,
	dev->mode_config.dpms_property,
	&dpms_status);
	if (ret)
	return 0;

	return snprintf(buf, PAGE_SIZE, "%s\n",
	drm_get_dpms_name((int)dpms_status));
	}

	static ssize_t enabled_show(struct device *device,
	struct device_attribute *attr,
	char *buf)
	{
	struct drm_connector *connector = to_drm_connector(device);

	return snprintf(buf, PAGE_SIZE, "%s\n", connector->encoder ? "enabled" :
	"disabled");
	}

	static ssize_t edid_show(struct file filp, struct kobject kobj,
	struct bin_attribute attr, char buf, loff_t off,
	size_t count)
	{
	struct device *connector_dev = container_of(kobj, struct device, kobj);
	struct drm_connector *connector = to_drm_connector(connector_dev);
	unsigned char *edid;
	size_t size;

	if (!connector->edid_blob_ptr)
	return 0;

	edid = connector->edid_blob_ptr->data;
	size = connector->edid_blob_ptr->length;
	if (!edid)
	return 0;

	if (off >= size)
	return 0;

	if (off + count > size)
	count = size - off;
	memcpy(buf, edid + off, count);

	return count;
	}

	static ssize_t modes_show(struct device *device,
	struct device_attribute *attr,
	char *buf)
	{
	struct drm_connector *connector = to_drm_connector(device);
	struct drm_display_mode *mode;
	int written = 0;

	list_for_each_entry(mode, &connector->modes, head) {
	written += snprintf(buf + written, PAGE_SIZE - written, "%s\n",
	mode->name);
	}

	return written;
	}

	static ssize_t subconnector_show(struct device *device,
	struct device_attribute *attr,
	char *buf)
	{
	struct drm_connector *connector = to_drm_connector(device);
	struct drm_device *dev = connector->dev;
	struct drm_property *prop = NULL;
	uint64_t subconnector;
	int is_tv = 0;
	int ret;

	switch (connector->connector_type) {
	case DRM_MODE_CONNECTOR_DVII:
	prop = dev->mode_config.dvi_i_subconnector_property;
	break;
	case DRM_MODE_CONNECTOR_Composite:
	case DRM_MODE_CONNECTOR_SVIDEO:
	case DRM_MODE_CONNECTOR_Component:
	case DRM_MODE_CONNECTOR_TV:
	prop = dev->mode_config.tv_subconnector_property;
	is_tv = 1;
	break;
	default:
	DRM_ERROR("Wrong connector type for this property\n");
	return 0;
	}

	if (!prop) {
	DRM_ERROR("Unable to find subconnector property\n");
	return 0;
	}

	ret = drm_object_property_get_value(&connector->base, prop, &subconnector);
	if (ret)
	return 0;

	return snprintf(buf, PAGE_SIZE, "%s", is_tv ?
	drm_get_tv_subconnector_name((int)subconnector) :
	drm_get_dvi_i_subconnector_name((int)subconnector));
	}

	static ssize_t select_subconnector_show(struct device *device,
	struct device_attribute *attr,
	char *buf)
	{
	struct drm_connector *connector = to_drm_connector(device);
	struct drm_device *dev = connector->dev;
	struct drm_property *prop = NULL;
	uint64_t subconnector;
	int is_tv = 0;
	int ret;

	switch (connector->connector_type) {
	case DRM_MODE_CONNECTOR_DVII:
	prop = dev->mode_config.dvi_i_select_subconnector_property;
	break;
	case DRM_MODE_CONNECTOR_Composite:
	case DRM_MODE_CONNECTOR_SVIDEO:
	case DRM_MODE_CONNECTOR_Component:
	case DRM_MODE_CONNECTOR_TV:
	prop = dev->mode_config.tv_select_subconnector_property;
	is_tv = 1;
	break;
	default:
	DRM_ERROR("Wrong connector type for this property\n");
	return 0;
	}

	if (!prop) {
	DRM_ERROR("Unable to find select subconnector property\n");
	return 0;
	}

	ret = drm_object_property_get_value(&connector->base, prop, &subconnector);
	if (ret)
	return 0;

	return snprintf(buf, PAGE_SIZE, "%s", is_tv ?
	drm_get_tv_select_name((int)subconnector) :
	drm_get_dvi_i_select_name((int)subconnector));
	}

	static struct device_attribute connector_attrs[] = {
	__ATTR_RO(status),
	__ATTR_RO(enabled),
	__ATTR_RO(dpms),
	__ATTR_RO(modes),
	};

	/* These attributes are for both DVI-I connectors and all types of tv-out. */
	static struct device_attribute connector_attrs_opt1[] = {
	__ATTR_RO(subconnector),
	__ATTR_RO(select_subconnector),
	};

	static struct bin_attribute edid_attr = {
	.attr.name = "edid",
	.attr.mode = 0444,
	.size = 0,
	.read = edid_show,
	};

	/**
	* drm_sysfs_connector_add - add a connector to sysfs
	* @connector: connector to add
	*
	* Create a connector device in sysfs, along with its associated connector
	* properties (so far, connection status, dpms, mode list & edid) and
	* generate a hotplug event so userspace knows there's a new connector
	* available.
	*/
	int drm_sysfs_connector_add(struct drm_connector *connector)
	{
	struct drm_device *dev = connector->dev;
	int attr_cnt = 0;
	int opt_cnt = 0;
	int i;
	int ret;

	if (connector->kdev)
	return 0;

	connector->kdev = device_create(drm_class, dev->primary->kdev,
	0, connector, "card%d-%s",
	dev->primary->index, drm_get_connector_name(connector));
	DRM_DEBUG("adding \"%s\" to sysfs\n",
	drm_get_connector_name(connector));

	if (IS_ERR(connector->kdev)) {
	DRM_ERROR("failed to register connector device: %ld\n", PTR_ERR(connector->kdev));
	ret = PTR_ERR(connector->kdev);
	goto out;
	}

	/* Standard attributes */

	for (attr_cnt = 0; attr_cnt < ARRAY_SIZE(connector_attrs); attr_cnt++) {
	ret = device_create_file(connector->kdev, &connector_attrs[attr_cnt]);
	if (ret)
	goto err_out_files;
	}

	/* Optional attributes */
	/*
	* In the long run it maybe a good idea to make one set of
	* optionals per connector type.
	*/
	switch (connector->connector_type) {
	case DRM_MODE_CONNECTOR_DVII:
	case DRM_MODE_CONNECTOR_Composite:
	case DRM_MODE_CONNECTOR_SVIDEO:
	case DRM_MODE_CONNECTOR_Component:
	case DRM_MODE_CONNECTOR_TV:
	for (opt_cnt = 0; opt_cnt < ARRAY_SIZE(connector_attrs_opt1); opt_cnt++) {
	ret = device_create_file(connector->kdev, &connector_attrs_opt1[opt_cnt]);
	if (ret)
	goto err_out_files;
	}
	break;
	default:
	break;
	}

	ret = sysfs_create_bin_file(&connector->kdev->kobj, &edid_attr);
	if (ret)
	goto err_out_files;

	/* Let userspace know we have a new connector */
	drm_sysfs_hotplug_event(dev);

	return 0;

	err_out_files:
	for (i = 0; i < opt_cnt; i++)
	device_remove_file(connector->kdev, &connector_attrs_opt1[i]);
	for (i = 0; i < attr_cnt; i++)
	device_remove_file(connector->kdev, &connector_attrs[i]);
	device_unregister(connector->kdev);

	out:
	return ret;
	}
	EXPORT_SYMBOL(drm_sysfs_connector_add);

	/**
	* drm_sysfs_connector_remove - remove an connector device from sysfs
	* @connector: connector to remove
	*
	* Remove @connector and its associated attributes from sysfs. Note that
	* the device model core will take care of sending the "remove" uevent
	* at this time, so we don't need to do it.
	*
	* Note:
	* This routine should only be called if the connector was previously
	* successfully registered. If @connector hasn't been registered yet,
	* you'll likely see a panic somewhere deep in sysfs code when called.
	*/
	void drm_sysfs_connector_remove(struct drm_connector *connector)
	{
	int i;

	if (!connector->kdev)
	return;
	DRM_DEBUG("removing \"%s\" from sysfs\n",
	drm_get_connector_name(connector));

	for (i = 0; i < ARRAY_SIZE(connector_attrs); i++)
	device_remove_file(connector->kdev, &connector_attrs[i]);
	sysfs_remove_bin_file(&connector->kdev->kobj, &edid_attr);
	device_unregister(connector->kdev);
	connector->kdev = NULL;
	}
	EXPORT_SYMBOL(drm_sysfs_connector_remove);

	/**
	* drm_sysfs_hotplug_event - generate a DRM uevent
	* @dev: DRM device
	*
	* Send a uevent for the DRM device specified by @dev. Currently we only
	* set HOTPLUG=1 in the uevent environment, but this could be expanded to
	* deal with other types of events.
	*/
	void drm_sysfs_hotplug_event(struct drm_device *dev)
	{
	char *event_string = "HOTPLUG=1";
	char *envp[] = { event_string, NULL };

	DRM_DEBUG("generating hotplug event\n");

	kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
	}
	EXPORT_SYMBOL(drm_sysfs_hotplug_event);

	/**
	* drm_sysfs_device_add - adds a class device to sysfs for a character driver
	* @dev: DRM device to be added
	* @head: DRM head in question
	*
	* Add a DRM device to the DRM's device model class. We use @dev's PCI device
	* as the parent for the Linux device, and make sure it has a file containing
	* the driver we're using (for userspace compatibility).
	*/
	int drm_sysfs_device_add(struct drm_minor *minor)
	{
	char *minor_str;

	if (minor->type == DRM_MINOR_CONTROL)
	minor_str = "controlD%d";
	else if (minor->type == DRM_MINOR_RENDER)
	minor_str = "renderD%d";
	else
	minor_str = "card%d";

	minor->kdev = device_create(drm_class, minor->dev->dev,
	MKDEV(DRM_MAJOR, minor->index),
	minor, minor_str, minor->index);
	if (IS_ERR(minor->kdev)) {
	DRM_ERROR("device create failed %ld\n", PTR_ERR(minor->kdev));
	return PTR_ERR(minor->kdev);
	}
	return 0;
	}

	/**
	* drm_sysfs_device_remove - remove DRM device
	* @dev: DRM device to remove
	*
	* This call unregisters and cleans up a class device that was created with a
	* call to drm_sysfs_device_add()
	*/
	void drm_sysfs_device_remove(struct drm_minor *minor)
	{
	if (minor->kdev)
	device_destroy(drm_class, MKDEV(DRM_MAJOR, minor->index));
	minor->kdev = NULL;
	}


	/**
	* drm_class_device_register - Register a struct device in the drm class.
	*
	* @dev: pointer to struct device to register.
	*
	* @dev should have all relevant members pre-filled with the exception
	* of the class member. In particular, the device_type member must
	* be set.
	*/

	int drm_class_device_register(struct device *dev)
	{
	if (!drm_class \|\| IS_ERR(drm_class))
	return -ENOENT;

	dev->class = drm_class;
	return device_register(dev);
	}
	EXPORT_SYMBOL_GPL(drm_class_device_register);

	void drm_class_device_unregister(struct device *dev)
	{
	return device_unregister(dev);
	}
	EXPORT_SYMBOL_GPL(drm_class_device_unregister);