Improved DRM sysfs support

This patch ties outputs, output properties and hotplug events into the
DRM core.  Each output has a corresponding directory under the primary
DRM device (usually card0) containing dpms, edid, modes, and connection
status files.

New hotplug change events occur when outputs are added or hotplug events
are detected.

1 files changed, 188 insertions, 9 deletions

diff --git a/linux-core/drm_sysfs.c b/linux-core/drm_sysfs.c
index 3372a713..3e682c99 100644
--- a/linux-core/drm_sysfs.c
+++ b/linux-core/drm_sysfs.c
@@ -133,10 +133,6 @@ static ssize_t show_dri(struct device *device, struct device_attribute *attr,
 	return snprintf(buf, PAGE_SIZE, "%s\n", drm_dev->driver->pci_driver.name);
 }
 
-static struct device_attribute device_attrs[] = {
-	__ATTR(dri_library_name, S_IRUGO, show_dri, NULL),
-};
-
 /**
  * drm_sysfs_device_release - do nothing
  * @dev: Linux device
@@ -150,6 +146,189 @@ static void drm_sysfs_device_release(struct device *dev)
 	return;
 }
 
+/*
+ * Output properties
+ */
+static ssize_t status_show(struct device *device,
+			   struct device_attribute *attr,
+			   char *buf)
+{
+	struct drm_output *output = container_of(device, struct drm_output, kdev);
+	return snprintf(buf, PAGE_SIZE, "%s",
+			drm_get_output_status_name(output->funcs->detect(output)));
+}
+
+static ssize_t dpms_show(struct device *device,
+			   struct device_attribute *attr,
+			   char *buf)
+{
+	struct drm_output *output = container_of(device, struct drm_output, kdev);
+	struct drm_device *dev = output->dev;
+	uint64_t dpms_status;
+	int ret;
+
+	ret = drm_output_property_get_value(output,
+					    dev->mode_config.dpms_property,
+					    &dpms_status);
+	if (ret)
+		return 0;
+	
+	return snprintf(buf, PAGE_SIZE, "%s", drm_get_dpms_name((int)dpms_status));
+}
+
+static ssize_t edid_show(struct kobject *kobj, struct bin_attribute *attr,
+			 char *buf, loff_t off, size_t count)
+{
+	struct device *output_dev = container_of(kobj, struct device, kobj);
+	struct drm_output *output = container_of(output_dev, struct drm_output,
+						 kdev);
+	unsigned char *edid;
+	size_t size;
+
+	if (!output->edid_blob_ptr)
+		return 0;
+
+	edid = output->edid_blob_ptr->data;
+	size = output->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_output *output = container_of(device, struct drm_output, kdev);
+	struct drm_display_mode *mode;
+	int written = 0;
+
+	list_for_each_entry(mode, &output->modes, head) {
+		written += snprintf(buf + written, PAGE_SIZE - written, "%s\n",
+				    mode->name);
+	}
+
+	return written;
+}
+
+static struct device_attribute output_attrs[] = {
+	__ATTR_RO(status),
+	__ATTR_RO(dpms),
+	__ATTR_RO(modes),
+};
+
+static struct bin_attribute edid_attr = {
+	.attr.name = "edid",
+	.size = 128,
+	.read = edid_show,
+};
+
+/**
+ * drm_sysfs_output_add - add an output to sysfs
+ * @output: output to add
+ *
+ * Create an output device in sysfs, along with its associated output
+ * properties (so far, connection status, dpms, mode list & edid) and
+ * generate a hotplug event so userspace knows there's a new output
+ * available.
+ */
+int drm_sysfs_output_add(struct drm_output *output)
+{
+	struct drm_device *dev = output->dev;
+	int ret = 0, i, j;
+
+	if (device_is_registered(&output->kdev))
+	    return 0;
+
+	output->kdev.parent = &dev->primary->kdev;
+	output->kdev.class = drm_class;
+	output->kdev.release = drm_sysfs_device_release;
+
+	DRM_DEBUG("adding \"%s\" to sysfs", drm_get_output_name(output));
+
+	snprintf(output->kdev.bus_id, BUS_ID_SIZE, "card%d-%s",
+		 dev->primary->index, drm_get_output_name(output));
+	ret = device_register(&output->kdev);
+
+	if (ret) {
+		DRM_ERROR("failed to register output device: %d\n", ret);
+		goto out;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(output_attrs); i++) {
+		ret = device_create_file(&output->kdev, &output_attrs[i]);
+		if (ret)
+			goto err_out_files;
+	}
+
+	ret = sysfs_create_bin_file(&output->kdev.kobj, &edid_attr);
+	if (ret)
+		goto err_out_files;
+
+	/* Let userspace know we have a new output */
+	drm_sysfs_hotplug_event(dev);
+
+	return 0;
+
+err_out_files:
+	if (i > 0)
+		for (j = 0; j < i; j++)
+			device_remove_file(&output->kdev, &output_attrs[i]);
+	device_unregister(&output->kdev);
+
+out:
+	return ret;
+}
+
+/**
+ * drm_sysfs_output_remove - remove an output device from sysfs
+ * @output: output to remove
+ *
+ * Remove @output 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.
+ */
+void drm_sysfs_output_remove(struct drm_output *output)
+{
+	int i;
+
+	DRM_DEBUG("removing \"%s\" from sysfs\n", drm_get_output_name(output));
+	for (i = 0; i < i; i++)
+		device_remove_file(&output->kdev, &output_attrs[i]);
+	sysfs_remove_bin_file(&output->kdev.kobj, &edid_attr);
+	device_unregister(&output->kdev);
+}
+
+/**
+ * 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);
+}
+
+static struct device_attribute dri_attrs[] = {
+	__ATTR(dri_library_name, S_IRUGO, show_dri, NULL),
+};
+
 /**
  * drm_sysfs_device_add - adds a class device to sysfs for a character driver
  * @dev: DRM device to be added
@@ -184,8 +363,8 @@ int drm_sysfs_device_add(struct drm_minor *minor)
 		goto err_out;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(device_attrs); i++) {
-		err = device_create_file(&minor->kdev, &device_attrs[i]);
+	for (i = 0; i < ARRAY_SIZE(dri_attrs); i++) {
+		err = device_create_file(&minor->kdev, &dri_attrs[i]);
 		if (err)
 			goto err_out_files;
 	}
@@ -195,7 +374,7 @@ int drm_sysfs_device_add(struct drm_minor *minor)
 err_out_files:
 	if (i > 0)
 		for (j = 0; j < i; j++)
-			device_remove_file(&minor->kdev, &device_attrs[i]);
+			device_remove_file(&minor->kdev, &dri_attrs[i]);
 	device_unregister(&minor->kdev);
 err_out:
 
@@ -213,7 +392,7 @@ void drm_sysfs_device_remove(struct drm_minor *minor)
 {
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(device_attrs); i++)
-		device_remove_file(&minor->kdev, &device_attrs[i]);
+	for (i = 0; i < ARRAY_SIZE(dri_attrs); i++)
+		device_remove_file(&minor->kdev, &dri_attrs[i]);
 	device_unregister(&minor->kdev);
 }