drivers/gpu/drm/drm_sysfs.c - kernel/msm-4.9 - 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>
 #include "drm_internal.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 DEVICE_ATTR_RO(status);
 static DEVICE_ATTR_RO(enabled);
 static DEVICE_ATTR_RO(dpms);
 static DEVICE_ATTR_RO(modes);

 static struct attribute *connector_dev_attrs[] = {
 	&dev_attr_status.attr,
 	&dev_attr_enabled.attr,
 	&dev_attr_dpms.attr,
 	&dev_attr_modes.attr,
 	NULL
 };

 /* These attributes are for both DVI-I connectors and all types of tv-out. */
 static DEVICE_ATTR_RO(subconnector);
 static DEVICE_ATTR_RO(select_subconnector);

 static struct attribute *connector_opt_dev_attrs[] = {
 	&dev_attr_subconnector.attr,
 	&dev_attr_select_subconnector.attr,
 	NULL
 };

 static umode_t connector_opt_dev_is_visible(struct kobject *kobj,
 					    struct attribute *attr, int idx)
 {
 	struct device *dev = kobj_to_dev(kobj);
 	struct drm_connector *connector = to_drm_connector(dev);

 	/*
 	 * 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:
 		return attr->mode;
 	}

 	return 0;
 }

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

 static struct bin_attribute *connector_bin_attrs[] = {
 	&edid_attr,
 	NULL
 };

 static const struct attribute_group connector_dev_group = {
 	.attrs = connector_dev_attrs,
 	.bin_attrs = connector_bin_attrs,
 };

 static const struct attribute_group connector_opt_dev_group = {
 	.attrs = connector_opt_dev_attrs,
 	.is_visible = connector_opt_dev_is_visible,
 };

 static const struct attribute_group *connector_dev_groups[] = {
 	&connector_dev_group,
 	&connector_opt_dev_group,
 	NULL
 };

 /**
  * 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;

 	if (connector->kdev)
 		return 0;

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

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

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

 	return 0;
 }

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

 	device_unregister(connector->kdev);
 	connector->kdev = NULL;
 }

 /**
  * 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);

 static void drm_sysfs_release(struct device *dev)
 {
 	kfree(dev);
 }

 /**
  * drm_sysfs_minor_alloc() - Allocate sysfs device for given minor
  * @minor: minor to allocate sysfs device for
  *
  * This allocates a new sysfs device for @minor and returns it. The device is
  * not registered nor linked. The caller has to use device_add() and
  * device_del() to register and unregister it.
  *
  * Note that dev_get_drvdata() on the new device will return the minor.
  * However, the device does not hold a ref-count to the minor nor to the
  * underlying drm_device. This is unproblematic as long as you access the
  * private data only in sysfs callbacks. device_del() disables those
  * synchronously, so they cannot be called after you cleanup a minor.
  */
 struct device *drm_sysfs_minor_alloc(struct drm_minor *minor)
 {
 	const char *minor_str;
 	struct device *kdev;
 	int r;

 	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";

 	kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
 	if (!kdev)
 		return ERR_PTR(-ENOMEM);

 	device_initialize(kdev);
 	kdev->devt = MKDEV(DRM_MAJOR, minor->index);
 	kdev->class = drm_class;
 	kdev->type = &drm_sysfs_device_minor;
 	kdev->parent = minor->dev->dev;
 	kdev->release = drm_sysfs_release;
 	dev_set_drvdata(kdev, minor);

 	r = dev_set_name(kdev, minor_str, minor->index);
 	if (r < 0)
 		goto err_free;

 	return kdev;

 err_free:
 	put_device(kdev);
 	return ERR_PTR(r);
 }

 /**
  * 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>
	#include "drm_internal.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 DEVICE_ATTR_RO(status);
	static DEVICE_ATTR_RO(enabled);
	static DEVICE_ATTR_RO(dpms);
	static DEVICE_ATTR_RO(modes);

	static struct attribute *connector_dev_attrs[] = {
	&dev_attr_status.attr,
	&dev_attr_enabled.attr,
	&dev_attr_dpms.attr,
	&dev_attr_modes.attr,
	NULL
	};

	/* These attributes are for both DVI-I connectors and all types of tv-out. */
	static DEVICE_ATTR_RO(subconnector);
	static DEVICE_ATTR_RO(select_subconnector);

	static struct attribute *connector_opt_dev_attrs[] = {
	&dev_attr_subconnector.attr,
	&dev_attr_select_subconnector.attr,
	NULL
	};

	static umode_t connector_opt_dev_is_visible(struct kobject *kobj,
	struct attribute *attr, int idx)
	{
	struct device *dev = kobj_to_dev(kobj);
	struct drm_connector *connector = to_drm_connector(dev);

	/*
	* 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:
	return attr->mode;
	}

	return 0;
	}

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

	static struct bin_attribute *connector_bin_attrs[] = {
	&edid_attr,
	NULL
	};

	static const struct attribute_group connector_dev_group = {
	.attrs = connector_dev_attrs,
	.bin_attrs = connector_bin_attrs,
	};

	static const struct attribute_group connector_opt_dev_group = {
	.attrs = connector_opt_dev_attrs,
	.is_visible = connector_opt_dev_is_visible,
	};

	static const struct attribute_group *connector_dev_groups[] = {
	&connector_dev_group,
	&connector_opt_dev_group,
	NULL
	};

	/**
	* 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;

	if (connector->kdev)
	return 0;

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

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

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

	return 0;
	}

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

	device_unregister(connector->kdev);
	connector->kdev = NULL;
	}

	/**
	* 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);

	static void drm_sysfs_release(struct device *dev)
	{
	kfree(dev);
	}

	/**
	* drm_sysfs_minor_alloc() - Allocate sysfs device for given minor
	* @minor: minor to allocate sysfs device for
	*
	* This allocates a new sysfs device for @minor and returns it. The device is
	* not registered nor linked. The caller has to use device_add() and
	* device_del() to register and unregister it.
	*
	* Note that dev_get_drvdata() on the new device will return the minor.
	* However, the device does not hold a ref-count to the minor nor to the
	* underlying drm_device. This is unproblematic as long as you access the
	* private data only in sysfs callbacks. device_del() disables those
	* synchronously, so they cannot be called after you cleanup a minor.
	*/
	struct device drm_sysfs_minor_alloc(struct drm_minor minor)
	{
	const char *minor_str;
	struct device *kdev;
	int r;

	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";

	kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
	if (!kdev)
	return ERR_PTR(-ENOMEM);

	device_initialize(kdev);
	kdev->devt = MKDEV(DRM_MAJOR, minor->index);
	kdev->class = drm_class;
	kdev->type = &drm_sysfs_device_minor;
	kdev->parent = minor->dev->dev;
	kdev->release = drm_sysfs_release;
	dev_set_drvdata(kdev, minor);

	r = dev_set_name(kdev, minor_str, minor->index);
	if (r < 0)
	goto err_free;

	return kdev;

	err_free:
	put_device(kdev);
	return ERR_PTR(r);
	}

	/**
	* 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);