drm: Add helper for simple display pipeline

Provides helper functions for drivers that have a simple display
pipeline. Plane, crtc and encoder are collapsed into one entity.

Changes since v4:
- Remove drm_connector_register() call
- Forgot to assign pipe->connector

Changes since v3:
- (struct drm_simple_display_pipe *)->funcs should be const

Changes since v2:
- Drop Kconfig knob DRM_KMS_HELPER
- Expand documentation

Changes since v1:
- Add DOC header and add to gpu.tmpl
- Fix docs: @funcs is optional, "negative error code",
  "This hook is optional."
- Add checks to drm_simple_kms_plane_atomic_check()

Cc: jsarha@ti.com
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1465570559-14238-1-git-send-email-noralf@tronnes.org

1 files changed, 94 insertions, 0 deletions

diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h
new file mode 100644
index 000000000000..269039722f91
--- /dev/null
+++ b/include/drm/drm_simple_kms_helper.h
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2016 Noralf Trønnes
+ *
+ * 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.
+ */
+
+#ifndef __LINUX_DRM_SIMPLE_KMS_HELPER_H
+#define __LINUX_DRM_SIMPLE_KMS_HELPER_H
+
+struct drm_simple_display_pipe;
+
+/**
+ * struct drm_simple_display_pipe_funcs - helper operations for a simple
+ *                                        display pipeline
+ */
+struct drm_simple_display_pipe_funcs {
+	/**
+	 * @enable:
+	 *
+	 * This function should be used to enable the pipeline.
+	 * It is called when the underlying crtc is enabled.
+	 * This hook is optional.
+	 */
+	void (*enable)(struct drm_simple_display_pipe *pipe,
+		       struct drm_crtc_state *crtc_state);
+	/**
+	 * @disable:
+	 *
+	 * This function should be used to disable the pipeline.
+	 * It is called when the underlying crtc is disabled.
+	 * This hook is optional.
+	 */
+	void (*disable)(struct drm_simple_display_pipe *pipe);
+
+	/**
+	 * @check:
+	 *
+	 * This function is called in the check phase of an atomic update,
+	 * specifically when the underlying plane is checked.
+	 * The simple display pipeline helpers already check that the plane is
+	 * not scaled, fills the entire visible area and is always enabled
+	 * when the crtc is also enabled.
+	 * This hook is optional.
+	 *
+	 * RETURNS:
+	 *
+	 * 0 on success, -EINVAL if the state or the transition can't be
+	 * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
+	 * attempt to obtain another state object ran into a &drm_modeset_lock
+	 * deadlock.
+	 */
+	int (*check)(struct drm_simple_display_pipe *pipe,
+		     struct drm_plane_state *plane_state,
+		     struct drm_crtc_state *crtc_state);
+	/**
+	 * @update:
+	 *
+	 * This function is called when the underlying plane state is updated.
+	 * This hook is optional.
+	 */
+	void (*update)(struct drm_simple_display_pipe *pipe,
+		       struct drm_plane_state *plane_state);
+};
+
+/**
+ * struct drm_simple_display_pipe - simple display pipeline
+ * @crtc: CRTC control structure
+ * @plane: Plane control structure
+ * @encoder: Encoder control structure
+ * @connector: Connector control structure
+ * @funcs: Pipeline control functions (optional)
+ *
+ * Simple display pipeline with plane, crtc and encoder collapsed into one
+ * entity. It should be initialized by calling drm_simple_display_pipe_init().
+ */
+struct drm_simple_display_pipe {
+	struct drm_crtc crtc;
+	struct drm_plane plane;
+	struct drm_encoder encoder;
+	struct drm_connector *connector;
+
+	const struct drm_simple_display_pipe_funcs *funcs;
+};
+
+int drm_simple_display_pipe_init(struct drm_device *dev,
+			struct drm_simple_display_pipe *pipe,
+			const struct drm_simple_display_pipe_funcs *funcs,
+			const uint32_t *formats, unsigned int format_count,
+			struct drm_connector *connector);
+
+#endif /* __LINUX_DRM_SIMPLE_KMS_HELPER_H */