linux-imx

/*

 * Copyright © 2009 Keith Packard

 *

 * 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/kernel.h>

#include <linux/module.h>

#include <linux/delay.h>

#include <linux/init.h>

#include <linux/errno.h>

#include <linux/sched.h>

#include <linux/i2c.h>

#include <linux/seq_file.h>

#include <drm/drm_dp_helper.h>

#include <drm/drmP.h>

​

#include "drm_crtc_helper_internal.h"

​

/**

 * DOC: dp helpers

 *

 * These functions contain some common logic and helpers at various abstraction

 * levels to deal with Display Port sink devices and related things like DP aux

 * channel transfers, EDID reading over DP aux channels, decoding certain DPCD

 * blocks, ...

 */

​

/* Helpers for DP link training */

static u8 dp_link_status(const u8 link_status[DP_LINK_STATUS_SIZE], int r)

{

    return link_status[r - DP_LANE0_1_STATUS];

}

​

static u8 dp_get_lane_status(const u8 link_status[DP_LINK_STATUS_SIZE],

                 int lane)

{

    int i = DP_LANE0_1_STATUS + (lane >> 1);

    int s = (lane & 1) * 4;

    u8 l = dp_link_status(link_status, i);

    return (l >> s) & 0xf;

}

​

bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE],

              int lane_count)

{

    u8 lane_align;