905 lines
25 KiB
C
905 lines
25 KiB
C
/*
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* Copyright © 2009 Keith Packard
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*
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* Permission to use, copy, modify, distribute, and sell this software and its
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* documentation for any purpose is hereby granted without fee, provided that
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* the above copyright notice appear in all copies and that both that copyright
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* notice and this permission notice appear in supporting documentation, and
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* that the name of the copyright holders not be used in advertising or
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* publicity pertaining to distribution of the software without specific,
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* written prior permission. The copyright holders make no representations
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* about the suitability of this software for any purpose. It is provided "as
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* is" without express or implied warranty.
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*
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* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
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* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
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* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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* OF THIS SOFTWARE.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/i2c.h>
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#include <drm/drm_dp_helper.h>
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#include <drm/drm_dp_aux_dev.h>
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#include <drm/drmP.h>
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/**
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* DOC: dp helpers
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*
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* These functions contain some common logic and helpers at various abstraction
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* levels to deal with Display Port sink devices and related things like DP aux
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* channel transfers, EDID reading over DP aux channels, decoding certain DPCD
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* blocks, ...
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*/
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/* Helpers for DP link training */
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static u8 dp_link_status(const u8 link_status[DP_LINK_STATUS_SIZE], int r)
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{
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return link_status[r - DP_LANE0_1_STATUS];
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}
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static u8 dp_get_lane_status(const u8 link_status[DP_LINK_STATUS_SIZE],
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int lane)
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{
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int i = DP_LANE0_1_STATUS + (lane >> 1);
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int s = (lane & 1) * 4;
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u8 l = dp_link_status(link_status, i);
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return (l >> s) & 0xf;
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}
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bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
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int lane_count)
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{
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u8 lane_align;
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u8 lane_status;
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int lane;
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lane_align = dp_link_status(link_status,
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DP_LANE_ALIGN_STATUS_UPDATED);
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if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0)
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return false;
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for (lane = 0; lane < lane_count; lane++) {
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lane_status = dp_get_lane_status(link_status, lane);
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if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS)
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return false;
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}
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return true;
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}
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EXPORT_SYMBOL(drm_dp_channel_eq_ok);
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bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
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int lane_count)
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{
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int lane;
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u8 lane_status;
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for (lane = 0; lane < lane_count; lane++) {
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lane_status = dp_get_lane_status(link_status, lane);
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if ((lane_status & DP_LANE_CR_DONE) == 0)
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return false;
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}
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return true;
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}
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EXPORT_SYMBOL(drm_dp_clock_recovery_ok);
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u8 drm_dp_get_adjust_request_voltage(const u8 link_status[DP_LINK_STATUS_SIZE],
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int lane)
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{
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int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
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int s = ((lane & 1) ?
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DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT :
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DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT);
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u8 l = dp_link_status(link_status, i);
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return ((l >> s) & 0x3) << DP_TRAIN_VOLTAGE_SWING_SHIFT;
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}
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EXPORT_SYMBOL(drm_dp_get_adjust_request_voltage);
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u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SIZE],
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int lane)
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{
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int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
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int s = ((lane & 1) ?
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DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT :
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DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT);
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u8 l = dp_link_status(link_status, i);
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return ((l >> s) & 0x3) << DP_TRAIN_PRE_EMPHASIS_SHIFT;
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}
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EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis);
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void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) {
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if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0)
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udelay(100);
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else
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mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4);
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}
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EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay);
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void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) {
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if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0)
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udelay(400);
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else
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mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4);
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}
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EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay);
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u8 drm_dp_link_rate_to_bw_code(int link_rate)
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{
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switch (link_rate) {
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case 162000:
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default:
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return DP_LINK_BW_1_62;
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case 270000:
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return DP_LINK_BW_2_7;
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case 540000:
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return DP_LINK_BW_5_4;
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}
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}
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EXPORT_SYMBOL(drm_dp_link_rate_to_bw_code);
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int drm_dp_bw_code_to_link_rate(u8 link_bw)
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{
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switch (link_bw) {
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case DP_LINK_BW_1_62:
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default:
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return 162000;
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case DP_LINK_BW_2_7:
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return 270000;
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case DP_LINK_BW_5_4:
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return 540000;
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}
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}
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EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate);
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#define AUX_RETRY_INTERVAL 500 /* us */
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/**
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* DOC: dp helpers
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*
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* The DisplayPort AUX channel is an abstraction to allow generic, driver-
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* independent access to AUX functionality. Drivers can take advantage of
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* this by filling in the fields of the drm_dp_aux structure.
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*
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* Transactions are described using a hardware-independent drm_dp_aux_msg
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* structure, which is passed into a driver's .transfer() implementation.
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* Both native and I2C-over-AUX transactions are supported.
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*/
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static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request,
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unsigned int offset, void *buffer, size_t size)
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{
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struct drm_dp_aux_msg msg;
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unsigned int retry, native_reply;
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int err = 0, ret = 0;
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memset(&msg, 0, sizeof(msg));
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msg.address = offset;
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msg.request = request;
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msg.buffer = buffer;
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msg.size = size;
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mutex_lock(&aux->hw_mutex);
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/*
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* The specification doesn't give any recommendation on how often to
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* retry native transactions. We used to retry 7 times like for
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* aux i2c transactions but real world devices this wasn't
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* sufficient, bump to 32 which makes Dell 4k monitors happier.
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*/
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for (retry = 0; retry < 32; retry++) {
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if (ret != 0 && ret != -ETIMEDOUT) {
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usleep_range(AUX_RETRY_INTERVAL,
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AUX_RETRY_INTERVAL + 100);
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}
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ret = aux->transfer(aux, &msg);
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if (ret >= 0) {
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native_reply = msg.reply & DP_AUX_NATIVE_REPLY_MASK;
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if (native_reply == DP_AUX_NATIVE_REPLY_ACK) {
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if (ret == size)
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goto unlock;
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ret = -EPROTO;
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} else
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ret = -EIO;
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}
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/*
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* We want the error we return to be the error we received on
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* the first transaction, since we may get a different error the
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* next time we retry
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*/
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if (!err)
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err = ret;
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}
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DRM_DEBUG_KMS("Too many retries, giving up. First error: %d\n", err);
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ret = err;
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unlock:
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mutex_unlock(&aux->hw_mutex);
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return ret;
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}
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/**
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* drm_dp_dpcd_read() - read a series of bytes from the DPCD
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* @aux: DisplayPort AUX channel
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* @offset: address of the (first) register to read
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* @buffer: buffer to store the register values
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* @size: number of bytes in @buffer
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*
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* Returns the number of bytes transferred on success, or a negative error
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* code on failure. -EIO is returned if the request was NAKed by the sink or
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* if the retry count was exceeded. If not all bytes were transferred, this
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* function returns -EPROTO. Errors from the underlying AUX channel transfer
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* function, with the exception of -EBUSY (which causes the transaction to
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* be retried), are propagated to the caller.
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*/
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ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset,
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void *buffer, size_t size)
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{
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int ret;
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/*
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* HP ZR24w corrupts the first DPCD access after entering power save
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* mode. Eg. on a read, the entire buffer will be filled with the same
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* byte. Do a throw away read to avoid corrupting anything we care
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* about. Afterwards things will work correctly until the monitor
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* gets woken up and subsequently re-enters power save mode.
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*
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* The user pressing any button on the monitor is enough to wake it
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* up, so there is no particularly good place to do the workaround.
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* We just have to do it before any DPCD access and hope that the
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* monitor doesn't power down exactly after the throw away read.
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*/
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ret = drm_dp_dpcd_access(aux, DP_AUX_NATIVE_READ, DP_DPCD_REV, buffer,
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1);
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if (ret != 1)
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return ret;
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return drm_dp_dpcd_access(aux, DP_AUX_NATIVE_READ, offset, buffer,
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size);
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}
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EXPORT_SYMBOL(drm_dp_dpcd_read);
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/**
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* drm_dp_dpcd_write() - write a series of bytes to the DPCD
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* @aux: DisplayPort AUX channel
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* @offset: address of the (first) register to write
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* @buffer: buffer containing the values to write
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* @size: number of bytes in @buffer
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*
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* Returns the number of bytes transferred on success, or a negative error
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* code on failure. -EIO is returned if the request was NAKed by the sink or
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* if the retry count was exceeded. If not all bytes were transferred, this
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* function returns -EPROTO. Errors from the underlying AUX channel transfer
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* function, with the exception of -EBUSY (which causes the transaction to
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* be retried), are propagated to the caller.
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*/
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ssize_t drm_dp_dpcd_write(struct drm_dp_aux *aux, unsigned int offset,
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void *buffer, size_t size)
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{
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return drm_dp_dpcd_access(aux, DP_AUX_NATIVE_WRITE, offset, buffer,
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size);
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}
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EXPORT_SYMBOL(drm_dp_dpcd_write);
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/**
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* drm_dp_dpcd_read_link_status() - read DPCD link status (bytes 0x202-0x207)
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* @aux: DisplayPort AUX channel
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* @status: buffer to store the link status in (must be at least 6 bytes)
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*
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* Returns the number of bytes transferred on success or a negative error
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* code on failure.
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*/
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int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,
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u8 status[DP_LINK_STATUS_SIZE])
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{
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return drm_dp_dpcd_read(aux, DP_LANE0_1_STATUS, status,
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DP_LINK_STATUS_SIZE);
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}
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EXPORT_SYMBOL(drm_dp_dpcd_read_link_status);
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/**
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* drm_dp_link_probe() - probe a DisplayPort link for capabilities
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* @aux: DisplayPort AUX channel
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* @link: pointer to structure in which to return link capabilities
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*
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* The structure filled in by this function can usually be passed directly
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* into drm_dp_link_power_up() and drm_dp_link_configure() to power up and
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* configure the link based on the link's capabilities.
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*
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* Returns 0 on success or a negative error code on failure.
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*/
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int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link)
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{
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u8 values[3];
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int err;
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memset(link, 0, sizeof(*link));
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err = drm_dp_dpcd_read(aux, DP_DPCD_REV, values, sizeof(values));
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if (err < 0)
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return err;
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link->revision = values[0];
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link->rate = drm_dp_bw_code_to_link_rate(values[1]);
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link->num_lanes = values[2] & DP_MAX_LANE_COUNT_MASK;
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if (values[2] & DP_ENHANCED_FRAME_CAP)
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link->capabilities |= DP_LINK_CAP_ENHANCED_FRAMING;
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return 0;
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}
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EXPORT_SYMBOL(drm_dp_link_probe);
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/**
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* drm_dp_link_power_up() - power up a DisplayPort link
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* @aux: DisplayPort AUX channel
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* @link: pointer to a structure containing the link configuration
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*
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* Returns 0 on success or a negative error code on failure.
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*/
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int drm_dp_link_power_up(struct drm_dp_aux *aux, struct drm_dp_link *link)
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{
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u8 value;
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int err;
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/* DP_SET_POWER register is only available on DPCD v1.1 and later */
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if (link->revision < 0x11)
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return 0;
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err = drm_dp_dpcd_readb(aux, DP_SET_POWER, &value);
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if (err < 0)
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return err;
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value &= ~DP_SET_POWER_MASK;
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value |= DP_SET_POWER_D0;
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err = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value);
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if (err < 0)
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return err;
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/*
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* According to the DP 1.1 specification, a "Sink Device must exit the
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* power saving state within 1 ms" (Section 2.5.3.1, Table 5-52, "Sink
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* Control Field" (register 0x600).
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*/
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usleep_range(1000, 2000);
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return 0;
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}
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EXPORT_SYMBOL(drm_dp_link_power_up);
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/**
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* drm_dp_link_power_down() - power down a DisplayPort link
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* @aux: DisplayPort AUX channel
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* @link: pointer to a structure containing the link configuration
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*
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* Returns 0 on success or a negative error code on failure.
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*/
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int drm_dp_link_power_down(struct drm_dp_aux *aux, struct drm_dp_link *link)
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{
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u8 value;
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int err;
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/* DP_SET_POWER register is only available on DPCD v1.1 and later */
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if (link->revision < 0x11)
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return 0;
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err = drm_dp_dpcd_readb(aux, DP_SET_POWER, &value);
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if (err < 0)
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return err;
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value &= ~DP_SET_POWER_MASK;
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value |= DP_SET_POWER_D3;
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err = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value);
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if (err < 0)
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return err;
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return 0;
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}
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EXPORT_SYMBOL(drm_dp_link_power_down);
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/**
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* drm_dp_link_configure() - configure a DisplayPort link
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* @aux: DisplayPort AUX channel
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* @link: pointer to a structure containing the link configuration
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*
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* Returns 0 on success or a negative error code on failure.
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*/
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int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link)
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{
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u8 values[2];
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int err;
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values[0] = drm_dp_link_rate_to_bw_code(link->rate);
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values[1] = link->num_lanes;
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if (link->capabilities & DP_LINK_CAP_ENHANCED_FRAMING)
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values[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
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err = drm_dp_dpcd_write(aux, DP_LINK_BW_SET, values, sizeof(values));
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if (err < 0)
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return err;
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return 0;
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}
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EXPORT_SYMBOL(drm_dp_link_configure);
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|
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/*
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* I2C-over-AUX implementation
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*/
|
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|
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static u32 drm_dp_i2c_functionality(struct i2c_adapter *adapter)
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{
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return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
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I2C_FUNC_SMBUS_READ_BLOCK_DATA |
|
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I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
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I2C_FUNC_10BIT_ADDR;
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}
|
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|
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static void drm_dp_i2c_msg_write_status_update(struct drm_dp_aux_msg *msg)
|
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{
|
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/*
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* In case of i2c defer or short i2c ack reply to a write,
|
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* we need to switch to WRITE_STATUS_UPDATE to drain the
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* rest of the message
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*/
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if ((msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_I2C_WRITE) {
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msg->request &= DP_AUX_I2C_MOT;
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msg->request |= DP_AUX_I2C_WRITE_STATUS_UPDATE;
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}
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}
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|
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#define AUX_PRECHARGE_LEN 10 /* 10 to 16 */
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#define AUX_SYNC_LEN (16 + 4) /* preamble + AUX_SYNC_END */
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#define AUX_STOP_LEN 4
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#define AUX_CMD_LEN 4
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#define AUX_ADDRESS_LEN 20
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#define AUX_REPLY_PAD_LEN 4
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#define AUX_LENGTH_LEN 8
|
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|
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/*
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* Calculate the duration of the AUX request/reply in usec. Gives the
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* "best" case estimate, ie. successful while as short as possible.
|
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*/
|
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static int drm_dp_aux_req_duration(const struct drm_dp_aux_msg *msg)
|
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{
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int len = AUX_PRECHARGE_LEN + AUX_SYNC_LEN + AUX_STOP_LEN +
|
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AUX_CMD_LEN + AUX_ADDRESS_LEN + AUX_LENGTH_LEN;
|
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|
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if ((msg->request & DP_AUX_I2C_READ) == 0)
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len += msg->size * 8;
|
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|
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return len;
|
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}
|
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|
|
static int drm_dp_aux_reply_duration(const struct drm_dp_aux_msg *msg)
|
|
{
|
|
int len = AUX_PRECHARGE_LEN + AUX_SYNC_LEN + AUX_STOP_LEN +
|
|
AUX_CMD_LEN + AUX_REPLY_PAD_LEN;
|
|
|
|
/*
|
|
* For read we expect what was asked. For writes there will
|
|
* be 0 or 1 data bytes. Assume 0 for the "best" case.
|
|
*/
|
|
if (msg->request & DP_AUX_I2C_READ)
|
|
len += msg->size * 8;
|
|
|
|
return len;
|
|
}
|
|
|
|
#define I2C_START_LEN 1
|
|
#define I2C_STOP_LEN 1
|
|
#define I2C_ADDR_LEN 9 /* ADDRESS + R/W + ACK/NACK */
|
|
#define I2C_DATA_LEN 9 /* DATA + ACK/NACK */
|
|
|
|
/*
|
|
* Calculate the length of the i2c transfer in usec, assuming
|
|
* the i2c bus speed is as specified. Gives the the "worst"
|
|
* case estimate, ie. successful while as long as possible.
|
|
* Doesn't account the the "MOT" bit, and instead assumes each
|
|
* message includes a START, ADDRESS and STOP. Neither does it
|
|
* account for additional random variables such as clock stretching.
|
|
*/
|
|
static int drm_dp_i2c_msg_duration(const struct drm_dp_aux_msg *msg,
|
|
int i2c_speed_khz)
|
|
{
|
|
/* AUX bitrate is 1MHz, i2c bitrate as specified */
|
|
return DIV_ROUND_UP((I2C_START_LEN + I2C_ADDR_LEN +
|
|
msg->size * I2C_DATA_LEN +
|
|
I2C_STOP_LEN) * 1000, i2c_speed_khz);
|
|
}
|
|
|
|
/*
|
|
* Deterine how many retries should be attempted to successfully transfer
|
|
* the specified message, based on the estimated durations of the
|
|
* i2c and AUX transfers.
|
|
*/
|
|
static int drm_dp_i2c_retry_count(const struct drm_dp_aux_msg *msg,
|
|
int i2c_speed_khz)
|
|
{
|
|
int aux_time_us = drm_dp_aux_req_duration(msg) +
|
|
drm_dp_aux_reply_duration(msg);
|
|
int i2c_time_us = drm_dp_i2c_msg_duration(msg, i2c_speed_khz);
|
|
|
|
return DIV_ROUND_UP(i2c_time_us, aux_time_us + AUX_RETRY_INTERVAL);
|
|
}
|
|
|
|
/*
|
|
* FIXME currently assumes 10 kHz as some real world devices seem
|
|
* to require it. We should query/set the speed via DPCD if supported.
|
|
*/
|
|
static int dp_aux_i2c_speed_khz __read_mostly = 10;
|
|
module_param_unsafe(dp_aux_i2c_speed_khz, int, 0644);
|
|
MODULE_PARM_DESC(dp_aux_i2c_speed_khz,
|
|
"Assumed speed of the i2c bus in kHz, (1-400, default 10)");
|
|
|
|
/*
|
|
* Transfer a single I2C-over-AUX message and handle various error conditions,
|
|
* retrying the transaction as appropriate. It is assumed that the
|
|
* aux->transfer function does not modify anything in the msg other than the
|
|
* reply field.
|
|
*
|
|
* Returns bytes transferred on success, or a negative error code on failure.
|
|
*/
|
|
static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
|
|
{
|
|
unsigned int retry, defer_i2c;
|
|
int ret;
|
|
/*
|
|
* DP1.2 sections 2.7.7.1.5.6.1 and 2.7.7.1.6.6.1: A DP Source device
|
|
* is required to retry at least seven times upon receiving AUX_DEFER
|
|
* before giving up the AUX transaction.
|
|
*
|
|
* We also try to account for the i2c bus speed.
|
|
*/
|
|
int max_retries = max(7, drm_dp_i2c_retry_count(msg, dp_aux_i2c_speed_khz));
|
|
|
|
for (retry = 0, defer_i2c = 0; retry < (max_retries + defer_i2c); retry++) {
|
|
ret = aux->transfer(aux, msg);
|
|
if (ret < 0) {
|
|
if (ret == -EBUSY)
|
|
continue;
|
|
|
|
/*
|
|
* While timeouts can be errors, they're usually normal
|
|
* behavior (for instance, when a driver tries to
|
|
* communicate with a non-existant DisplayPort device).
|
|
* Avoid spamming the kernel log with timeout errors.
|
|
*/
|
|
if (ret == -ETIMEDOUT)
|
|
DRM_DEBUG_KMS_RATELIMITED("transaction timed out\n");
|
|
else
|
|
DRM_DEBUG_KMS("transaction failed: %d\n", ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
|
|
switch (msg->reply & DP_AUX_NATIVE_REPLY_MASK) {
|
|
case DP_AUX_NATIVE_REPLY_ACK:
|
|
/*
|
|
* For I2C-over-AUX transactions this isn't enough, we
|
|
* need to check for the I2C ACK reply.
|
|
*/
|
|
break;
|
|
|
|
case DP_AUX_NATIVE_REPLY_NACK:
|
|
DRM_DEBUG_KMS("native nack (result=%d, size=%zu)\n", ret, msg->size);
|
|
return -EREMOTEIO;
|
|
|
|
case DP_AUX_NATIVE_REPLY_DEFER:
|
|
DRM_DEBUG_KMS("native defer\n");
|
|
/*
|
|
* We could check for I2C bit rate capabilities and if
|
|
* available adjust this interval. We could also be
|
|
* more careful with DP-to-legacy adapters where a
|
|
* long legacy cable may force very low I2C bit rates.
|
|
*
|
|
* For now just defer for long enough to hopefully be
|
|
* safe for all use-cases.
|
|
*/
|
|
usleep_range(AUX_RETRY_INTERVAL, AUX_RETRY_INTERVAL + 100);
|
|
continue;
|
|
|
|
default:
|
|
DRM_ERROR("invalid native reply %#04x\n", msg->reply);
|
|
return -EREMOTEIO;
|
|
}
|
|
|
|
switch (msg->reply & DP_AUX_I2C_REPLY_MASK) {
|
|
case DP_AUX_I2C_REPLY_ACK:
|
|
/*
|
|
* Both native ACK and I2C ACK replies received. We
|
|
* can assume the transfer was successful.
|
|
*/
|
|
if (ret != msg->size)
|
|
drm_dp_i2c_msg_write_status_update(msg);
|
|
return ret;
|
|
|
|
case DP_AUX_I2C_REPLY_NACK:
|
|
DRM_DEBUG_KMS("I2C nack (result=%d, size=%zu\n", ret, msg->size);
|
|
aux->i2c_nack_count++;
|
|
return -EREMOTEIO;
|
|
|
|
case DP_AUX_I2C_REPLY_DEFER:
|
|
DRM_DEBUG_KMS("I2C defer\n");
|
|
/* DP Compliance Test 4.2.2.5 Requirement:
|
|
* Must have at least 7 retries for I2C defers on the
|
|
* transaction to pass this test
|
|
*/
|
|
aux->i2c_defer_count++;
|
|
if (defer_i2c < 7)
|
|
defer_i2c++;
|
|
usleep_range(AUX_RETRY_INTERVAL, AUX_RETRY_INTERVAL + 100);
|
|
drm_dp_i2c_msg_write_status_update(msg);
|
|
|
|
continue;
|
|
|
|
default:
|
|
DRM_ERROR("invalid I2C reply %#04x\n", msg->reply);
|
|
return -EREMOTEIO;
|
|
}
|
|
}
|
|
|
|
DRM_DEBUG_KMS("too many retries, giving up\n");
|
|
return -EREMOTEIO;
|
|
}
|
|
|
|
static void drm_dp_i2c_msg_set_request(struct drm_dp_aux_msg *msg,
|
|
const struct i2c_msg *i2c_msg)
|
|
{
|
|
msg->request = (i2c_msg->flags & I2C_M_RD) ?
|
|
DP_AUX_I2C_READ : DP_AUX_I2C_WRITE;
|
|
msg->request |= DP_AUX_I2C_MOT;
|
|
}
|
|
|
|
/*
|
|
* Keep retrying drm_dp_i2c_do_msg until all data has been transferred.
|
|
*
|
|
* Returns an error code on failure, or a recommended transfer size on success.
|
|
*/
|
|
static int drm_dp_i2c_drain_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *orig_msg)
|
|
{
|
|
int err, ret = orig_msg->size;
|
|
struct drm_dp_aux_msg msg = *orig_msg;
|
|
|
|
while (msg.size > 0) {
|
|
err = drm_dp_i2c_do_msg(aux, &msg);
|
|
if (err <= 0)
|
|
return err == 0 ? -EPROTO : err;
|
|
|
|
if (err < msg.size && err < ret) {
|
|
DRM_DEBUG_KMS("Partial I2C reply: requested %zu bytes got %d bytes\n",
|
|
msg.size, err);
|
|
ret = err;
|
|
}
|
|
|
|
msg.size -= err;
|
|
msg.buffer += err;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Bizlink designed DP->DVI-D Dual Link adapters require the I2C over AUX
|
|
* packets to be as large as possible. If not, the I2C transactions never
|
|
* succeed. Hence the default is maximum.
|
|
*/
|
|
static int dp_aux_i2c_transfer_size __read_mostly = DP_AUX_MAX_PAYLOAD_BYTES;
|
|
module_param_unsafe(dp_aux_i2c_transfer_size, int, 0644);
|
|
MODULE_PARM_DESC(dp_aux_i2c_transfer_size,
|
|
"Number of bytes to transfer in a single I2C over DP AUX CH message, (1-16, default 16)");
|
|
|
|
static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
|
|
int num)
|
|
{
|
|
struct drm_dp_aux *aux = adapter->algo_data;
|
|
unsigned int i, j;
|
|
unsigned transfer_size;
|
|
struct drm_dp_aux_msg msg;
|
|
int err = 0;
|
|
|
|
dp_aux_i2c_transfer_size = clamp(dp_aux_i2c_transfer_size, 1, DP_AUX_MAX_PAYLOAD_BYTES);
|
|
|
|
memset(&msg, 0, sizeof(msg));
|
|
|
|
for (i = 0; i < num; i++) {
|
|
msg.address = msgs[i].addr;
|
|
drm_dp_i2c_msg_set_request(&msg, &msgs[i]);
|
|
/* Send a bare address packet to start the transaction.
|
|
* Zero sized messages specify an address only (bare
|
|
* address) transaction.
|
|
*/
|
|
msg.buffer = NULL;
|
|
msg.size = 0;
|
|
err = drm_dp_i2c_do_msg(aux, &msg);
|
|
|
|
/*
|
|
* Reset msg.request in case in case it got
|
|
* changed into a WRITE_STATUS_UPDATE.
|
|
*/
|
|
drm_dp_i2c_msg_set_request(&msg, &msgs[i]);
|
|
|
|
if (err < 0)
|
|
break;
|
|
/* We want each transaction to be as large as possible, but
|
|
* we'll go to smaller sizes if the hardware gives us a
|
|
* short reply.
|
|
*/
|
|
transfer_size = dp_aux_i2c_transfer_size;
|
|
for (j = 0; j < msgs[i].len; j += msg.size) {
|
|
msg.buffer = msgs[i].buf + j;
|
|
msg.size = min(transfer_size, msgs[i].len - j);
|
|
|
|
err = drm_dp_i2c_drain_msg(aux, &msg);
|
|
|
|
/*
|
|
* Reset msg.request in case in case it got
|
|
* changed into a WRITE_STATUS_UPDATE.
|
|
*/
|
|
drm_dp_i2c_msg_set_request(&msg, &msgs[i]);
|
|
|
|
if (err < 0)
|
|
break;
|
|
transfer_size = err;
|
|
}
|
|
if (err < 0)
|
|
break;
|
|
}
|
|
if (err >= 0)
|
|
err = num;
|
|
/* Send a bare address packet to close out the transaction.
|
|
* Zero sized messages specify an address only (bare
|
|
* address) transaction.
|
|
*/
|
|
msg.request &= ~DP_AUX_I2C_MOT;
|
|
msg.buffer = NULL;
|
|
msg.size = 0;
|
|
(void)drm_dp_i2c_do_msg(aux, &msg);
|
|
|
|
return err;
|
|
}
|
|
|
|
static const struct i2c_algorithm drm_dp_i2c_algo = {
|
|
.functionality = drm_dp_i2c_functionality,
|
|
.master_xfer = drm_dp_i2c_xfer,
|
|
};
|
|
|
|
static struct drm_dp_aux *i2c_to_aux(struct i2c_adapter *i2c)
|
|
{
|
|
return container_of(i2c, struct drm_dp_aux, ddc);
|
|
}
|
|
|
|
static void lock_bus(struct i2c_adapter *i2c, unsigned int flags)
|
|
{
|
|
mutex_lock(&i2c_to_aux(i2c)->hw_mutex);
|
|
}
|
|
|
|
static int trylock_bus(struct i2c_adapter *i2c, unsigned int flags)
|
|
{
|
|
return mutex_trylock(&i2c_to_aux(i2c)->hw_mutex);
|
|
}
|
|
|
|
static void unlock_bus(struct i2c_adapter *i2c, unsigned int flags)
|
|
{
|
|
mutex_unlock(&i2c_to_aux(i2c)->hw_mutex);
|
|
}
|
|
|
|
/**
|
|
* drm_dp_aux_init() - minimally initialise an aux channel
|
|
* @aux: DisplayPort AUX channel
|
|
*
|
|
* If you need to use the drm_dp_aux's i2c adapter prior to registering it
|
|
* with the outside world, call drm_dp_aux_init() first. You must still
|
|
* call drm_dp_aux_register() once the connector has been registered to
|
|
* allow userspace access to the auxiliary DP channel.
|
|
*/
|
|
void drm_dp_aux_init(struct drm_dp_aux *aux)
|
|
{
|
|
mutex_init(&aux->hw_mutex);
|
|
|
|
aux->ddc.algo = &drm_dp_i2c_algo;
|
|
aux->ddc.algo_data = aux;
|
|
aux->ddc.retries = 3;
|
|
|
|
aux->ddc.lock_bus = lock_bus;
|
|
aux->ddc.trylock_bus = trylock_bus;
|
|
aux->ddc.unlock_bus = unlock_bus;
|
|
}
|
|
EXPORT_SYMBOL(drm_dp_aux_init);
|
|
|
|
/**
|
|
* drm_dp_aux_register() - initialise and register aux channel
|
|
* @aux: DisplayPort AUX channel
|
|
*
|
|
* Automatically calls drm_dp_aux_init() if this hasn't been done yet.
|
|
*
|
|
* Returns 0 on success or a negative error code on failure.
|
|
*/
|
|
int drm_dp_aux_register(struct drm_dp_aux *aux)
|
|
{
|
|
int ret;
|
|
|
|
if (!aux->ddc.algo)
|
|
drm_dp_aux_init(aux);
|
|
|
|
aux->ddc.class = I2C_CLASS_DDC;
|
|
aux->ddc.owner = THIS_MODULE;
|
|
aux->ddc.dev.parent = aux->dev;
|
|
aux->ddc.dev.of_node = aux->dev->of_node;
|
|
|
|
strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
|
|
sizeof(aux->ddc.name));
|
|
|
|
ret = drm_dp_aux_register_devnode(aux);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = i2c_add_adapter(&aux->ddc);
|
|
if (ret) {
|
|
drm_dp_aux_unregister_devnode(aux);
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(drm_dp_aux_register);
|
|
|
|
/**
|
|
* drm_dp_aux_unregister() - unregister an AUX adapter
|
|
* @aux: DisplayPort AUX channel
|
|
*/
|
|
void drm_dp_aux_unregister(struct drm_dp_aux *aux)
|
|
{
|
|
drm_dp_aux_unregister_devnode(aux);
|
|
i2c_del_adapter(&aux->ddc);
|
|
}
|
|
EXPORT_SYMBOL(drm_dp_aux_unregister);
|
|
|
|
#define PSR_SETUP_TIME(x) [DP_PSR_SETUP_TIME_ ## x >> DP_PSR_SETUP_TIME_SHIFT] = (x)
|
|
|
|
/**
|
|
* drm_dp_psr_setup_time() - PSR setup in time usec
|
|
* @psr_cap: PSR capabilities from DPCD
|
|
*
|
|
* Returns:
|
|
* PSR setup time for the panel in microseconds, negative
|
|
* error code on failure.
|
|
*/
|
|
int drm_dp_psr_setup_time(const u8 psr_cap[EDP_PSR_RECEIVER_CAP_SIZE])
|
|
{
|
|
static const u16 psr_setup_time_us[] = {
|
|
PSR_SETUP_TIME(330),
|
|
PSR_SETUP_TIME(275),
|
|
PSR_SETUP_TIME(165),
|
|
PSR_SETUP_TIME(110),
|
|
PSR_SETUP_TIME(55),
|
|
PSR_SETUP_TIME(0),
|
|
};
|
|
int i;
|
|
|
|
i = (psr_cap[1] & DP_PSR_SETUP_TIME_MASK) >> DP_PSR_SETUP_TIME_SHIFT;
|
|
if (i >= ARRAY_SIZE(psr_setup_time_us))
|
|
return -EINVAL;
|
|
|
|
return psr_setup_time_us[i];
|
|
}
|
|
EXPORT_SYMBOL(drm_dp_psr_setup_time);
|
|
|
|
#undef PSR_SETUP_TIME
|