linux-imx

/*

 * Copyright (c) 2016 Intel Corporation

 *

 * Permission to use, copy, modify, distribute, and sell this software and its

 * documentation for any purpose is hereby granted without fee, provided that

 * the above copyright notice appear in all copies and that both that copyright

 * notice and this permission notice appear in supporting documentation, and

 * that the name of the copyright holders not be used in advertising or

 * publicity pertaining to distribution of the software without specific,

 * written prior permission.  The copyright holders make no representations

 * about the suitability of this software for any purpose.  It is provided "as

 * is" without express or implied warranty.

 *

 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,

 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO

 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR

 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,

 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER

 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE

 * OF THIS SOFTWARE.

 */

​

#include <linux/export.h>

#include <drm/drmP.h>

#include <drm/drm_encoder.h>

​

#include "drm_crtc_internal.h"

​

/**

 * DOC: overview

 *

 * Encoders represent the connecting element between the CRTC (as the overall

 * pixel pipeline, represented by &struct drm_crtc) and the connectors (as the

 * generic sink entity, represented by &struct drm_connector). An encoder takes

 * pixel data from a CRTC and converts it to a format suitable for any attached

 * connector. Encoders are objects exposed to userspace, originally to allow

 * userspace to infer cloning and connector/CRTC restrictions. Unfortunately

 * almost all drivers get this wrong, making the uabi pretty much useless. On

 * top of that the exposed restrictions are too simple for today's hardware, and

 * the recommended way to infer restrictions is by using the

 * DRM_MODE_ATOMIC_TEST_ONLY flag for the atomic IOCTL.

 *

 * Otherwise encoders aren't used in the uapi at all (any modeset request from

 * userspace directly connects a connector with a CRTC), drivers are therefore

 * free to use them however they wish. Modeset helper libraries make strong use

 * of encoders to facilitate code sharing. But for more complex settings it is

 * usually better to move shared code into a separate &drm_bridge. Compared to

 * encoders, bridges also have the benefit of being purely an internal

 * abstraction since they are not exposed to userspace at all.

 *

 * Encoders are initialized with drm_encoder_init() and cleaned up using

 * drm_encoder_cleanup().

 */

static const struct drm_prop_enum_list drm_encoder_enum_list[] = {

    { DRM_MODE_ENCODER_NONE, "None" },

    { DRM_MODE_ENCODER_DAC, "DAC" },

    { DRM_MODE_ENCODER_TMDS, "TMDS" },

    { DRM_MODE_ENCODER_LVDS, "LVDS" },

    { DRM_MODE_ENCODER_TVDAC, "TV" },

    { DRM_MODE_ENCODER_VIRTUAL, "Virtual" },

    { DRM_MODE_ENCODER_DSI, "DSI" },

    { DRM_MODE_ENCODER_DPMST, "DP MST" },

    { DRM_MODE_ENCODER_DPI, "DPI" },