linux/drivers/gpu/drm/nouveau/nouveau_dp.c

737 lines
19 KiB
C

/*
* Copyright 2009 Red Hat Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* Authors: Ben Skeggs
*/
#include "drmP.h"
#include "nouveau_drv.h"
#include "nouveau_i2c.h"
#include "nouveau_connector.h"
#include "nouveau_encoder.h"
#include "nouveau_crtc.h"
/******************************************************************************
* aux channel util functions
*****************************************************************************/
#define AUX_DBG(fmt, args...) do { \
if (nouveau_reg_debug & NOUVEAU_REG_DEBUG_AUXCH) { \
NV_PRINTK(KERN_DEBUG, dev, "AUXCH(%d): " fmt, ch, ##args); \
} \
} while (0)
#define AUX_ERR(fmt, args...) NV_ERROR(dev, "AUXCH(%d): " fmt, ch, ##args)
static void
auxch_fini(struct drm_device *dev, int ch)
{
nv_mask(dev, 0x00e4e4 + (ch * 0x50), 0x00310000, 0x00000000);
}
static int
auxch_init(struct drm_device *dev, int ch)
{
const u32 unksel = 1; /* nfi which to use, or if it matters.. */
const u32 ureq = unksel ? 0x00100000 : 0x00200000;
const u32 urep = unksel ? 0x01000000 : 0x02000000;
u32 ctrl, timeout;
/* wait up to 1ms for any previous transaction to be done... */
timeout = 1000;
do {
ctrl = nv_rd32(dev, 0x00e4e4 + (ch * 0x50));
udelay(1);
if (!timeout--) {
AUX_ERR("begin idle timeout 0x%08x", ctrl);
return -EBUSY;
}
} while (ctrl & 0x03010000);
/* set some magic, and wait up to 1ms for it to appear */
nv_mask(dev, 0x00e4e4 + (ch * 0x50), 0x00300000, ureq);
timeout = 1000;
do {
ctrl = nv_rd32(dev, 0x00e4e4 + (ch * 0x50));
udelay(1);
if (!timeout--) {
AUX_ERR("magic wait 0x%08x\n", ctrl);
auxch_fini(dev, ch);
return -EBUSY;
}
} while ((ctrl & 0x03000000) != urep);
return 0;
}
static int
auxch_tx(struct drm_device *dev, int ch, u8 type, u32 addr, u8 *data, u8 size)
{
u32 ctrl, stat, timeout, retries;
u32 xbuf[4] = {};
int ret, i;
AUX_DBG("%d: 0x%08x %d\n", type, addr, size);
ret = auxch_init(dev, ch);
if (ret)
goto out;
stat = nv_rd32(dev, 0x00e4e8 + (ch * 0x50));
if (!(stat & 0x10000000)) {
AUX_DBG("sink not detected\n");
ret = -ENXIO;
goto out;
}
if (!(type & 1)) {
memcpy(xbuf, data, size);
for (i = 0; i < 16; i += 4) {
AUX_DBG("wr 0x%08x\n", xbuf[i / 4]);
nv_wr32(dev, 0x00e4c0 + (ch * 0x50) + i, xbuf[i / 4]);
}
}
ctrl = nv_rd32(dev, 0x00e4e4 + (ch * 0x50));
ctrl &= ~0x0001f0ff;
ctrl |= type << 12;
ctrl |= size - 1;
nv_wr32(dev, 0x00e4e0 + (ch * 0x50), addr);
/* retry transaction a number of times on failure... */
ret = -EREMOTEIO;
for (retries = 0; retries < 32; retries++) {
/* reset, and delay a while if this is a retry */
nv_wr32(dev, 0x00e4e4 + (ch * 0x50), 0x80000000 | ctrl);
nv_wr32(dev, 0x00e4e4 + (ch * 0x50), 0x00000000 | ctrl);
if (retries)
udelay(400);
/* transaction request, wait up to 1ms for it to complete */
nv_wr32(dev, 0x00e4e4 + (ch * 0x50), 0x00010000 | ctrl);
timeout = 1000;
do {
ctrl = nv_rd32(dev, 0x00e4e4 + (ch * 0x50));
udelay(1);
if (!timeout--) {
AUX_ERR("tx req timeout 0x%08x\n", ctrl);
goto out;
}
} while (ctrl & 0x00010000);
/* read status, and check if transaction completed ok */
stat = nv_mask(dev, 0x00e4e8 + (ch * 0x50), 0, 0);
if (!(stat & 0x000f0f00)) {
ret = 0;
break;
}
AUX_DBG("%02d 0x%08x 0x%08x\n", retries, ctrl, stat);
}
if (type & 1) {
for (i = 0; i < 16; i += 4) {
xbuf[i / 4] = nv_rd32(dev, 0x00e4d0 + (ch * 0x50) + i);
AUX_DBG("rd 0x%08x\n", xbuf[i / 4]);
}
memcpy(data, xbuf, size);
}
out:
auxch_fini(dev, ch);
return ret;
}
static u32
dp_link_bw_get(struct drm_device *dev, int or, int link)
{
u32 ctrl = nv_rd32(dev, 0x614300 + (or * 0x800));
if (!(ctrl & 0x000c0000))
return 162000;
return 270000;
}
static int
dp_lane_count_get(struct drm_device *dev, int or, int link)
{
u32 ctrl = nv_rd32(dev, NV50_SOR_DP_CTRL(or, link));
switch (ctrl & 0x000f0000) {
case 0x00010000: return 1;
case 0x00030000: return 2;
default:
return 4;
}
}
void
nouveau_dp_tu_update(struct drm_device *dev, int or, int link, u32 clk, u32 bpp)
{
const u32 symbol = 100000;
int bestTU = 0, bestVTUi = 0, bestVTUf = 0, bestVTUa = 0;
int TU, VTUi, VTUf, VTUa;
u64 link_data_rate, link_ratio, unk;
u32 best_diff = 64 * symbol;
u32 link_nr, link_bw, r;
/* calculate packed data rate for each lane */
link_nr = dp_lane_count_get(dev, or, link);
link_data_rate = (clk * bpp / 8) / link_nr;
/* calculate ratio of packed data rate to link symbol rate */
link_bw = dp_link_bw_get(dev, or, link);
link_ratio = link_data_rate * symbol;
r = do_div(link_ratio, link_bw);
for (TU = 64; TU >= 32; TU--) {
/* calculate average number of valid symbols in each TU */
u32 tu_valid = link_ratio * TU;
u32 calc, diff;
/* find a hw representation for the fraction.. */
VTUi = tu_valid / symbol;
calc = VTUi * symbol;
diff = tu_valid - calc;
if (diff) {
if (diff >= (symbol / 2)) {
VTUf = symbol / (symbol - diff);
if (symbol - (VTUf * diff))
VTUf++;
if (VTUf <= 15) {
VTUa = 1;
calc += symbol - (symbol / VTUf);
} else {
VTUa = 0;
VTUf = 1;
calc += symbol;
}
} else {
VTUa = 0;
VTUf = min((int)(symbol / diff), 15);
calc += symbol / VTUf;
}
diff = calc - tu_valid;
} else {
/* no remainder, but the hw doesn't like the fractional
* part to be zero. decrement the integer part and
* have the fraction add a whole symbol back
*/
VTUa = 0;
VTUf = 1;
VTUi--;
}
if (diff < best_diff) {
best_diff = diff;
bestTU = TU;
bestVTUa = VTUa;
bestVTUf = VTUf;
bestVTUi = VTUi;
if (diff == 0)
break;
}
}
if (!bestTU) {
NV_ERROR(dev, "DP: unable to find suitable config\n");
return;
}
/* XXX close to vbios numbers, but not right */
unk = (symbol - link_ratio) * bestTU;
unk *= link_ratio;
r = do_div(unk, symbol);
r = do_div(unk, symbol);
unk += 6;
nv_mask(dev, NV50_SOR_DP_CTRL(or, link), 0x000001fc, bestTU << 2);
nv_mask(dev, NV50_SOR_DP_SCFG(or, link), 0x010f7f3f, bestVTUa << 24 |
bestVTUf << 16 |
bestVTUi << 8 |
unk);
}
u8 *
nouveau_dp_bios_data(struct drm_device *dev, struct dcb_entry *dcb, u8 **entry)
{
struct drm_nouveau_private *dev_priv = dev->dev_private;
struct nvbios *bios = &dev_priv->vbios;
struct bit_entry d;
u8 *table;
int i;
if (bit_table(dev, 'd', &d)) {
NV_ERROR(dev, "BIT 'd' table not found\n");
return NULL;
}
if (d.version != 1) {
NV_ERROR(dev, "BIT 'd' table version %d unknown\n", d.version);
return NULL;
}
table = ROMPTR(bios, d.data[0]);
if (!table) {
NV_ERROR(dev, "displayport table pointer invalid\n");
return NULL;
}
switch (table[0]) {
case 0x20:
case 0x21:
case 0x30:
break;
default:
NV_ERROR(dev, "displayport table 0x%02x unknown\n", table[0]);
return NULL;
}
for (i = 0; i < table[3]; i++) {
*entry = ROMPTR(bios, table[table[1] + (i * table[2])]);
if (*entry && bios_encoder_match(dcb, ROM32((*entry)[0])))
return table;
}
NV_ERROR(dev, "displayport encoder table not found\n");
return NULL;
}
/******************************************************************************
* link training
*****************************************************************************/
struct dp_state {
struct dcb_entry *dcb;
u8 *table;
u8 *entry;
int auxch;
int crtc;
int or;
int link;
u8 *dpcd;
int link_nr;
u32 link_bw;
u8 stat[6];
u8 conf[4];
};
static void
dp_set_link_config(struct drm_device *dev, struct dp_state *dp)
{
struct drm_nouveau_private *dev_priv = dev->dev_private;
int or = dp->or, link = dp->link;
u8 *entry, sink[2];
u32 dp_ctrl;
u16 script;
NV_DEBUG_KMS(dev, "%d lanes at %d KB/s\n", dp->link_nr, dp->link_bw);
/* set selected link rate on source */
switch (dp->link_bw) {
case 270000:
nv_mask(dev, 0x614300 + (or * 0x800), 0x000c0000, 0x00040000);
sink[0] = DP_LINK_BW_2_7;
break;
default:
nv_mask(dev, 0x614300 + (or * 0x800), 0x000c0000, 0x00000000);
sink[0] = DP_LINK_BW_1_62;
break;
}
/* offset +0x0a of each dp encoder table entry is a pointer to another
* table, that has (among other things) pointers to more scripts that
* need to be executed, this time depending on link speed.
*/
entry = ROMPTR(&dev_priv->vbios, dp->entry[10]);
if (entry) {
if (dp->table[0] < 0x30) {
while (dp->link_bw < (ROM16(entry[0]) * 10))
entry += 4;
script = ROM16(entry[2]);
} else {
while (dp->link_bw < (entry[0] * 27000))
entry += 3;
script = ROM16(entry[1]);
}
nouveau_bios_run_init_table(dev, script, dp->dcb, dp->crtc);
}
/* configure lane count on the source */
dp_ctrl = ((1 << dp->link_nr) - 1) << 16;
sink[1] = dp->link_nr;
if (dp->dpcd[2] & DP_ENHANCED_FRAME_CAP) {
dp_ctrl |= 0x00004000;
sink[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
}
nv_mask(dev, NV50_SOR_DP_CTRL(or, link), 0x001f4000, dp_ctrl);
/* inform the sink of the new configuration */
auxch_tx(dev, dp->auxch, 8, DP_LINK_BW_SET, sink, 2);
}
static void
dp_set_training_pattern(struct drm_device *dev, struct dp_state *dp, u8 tp)
{
u8 sink_tp;
NV_DEBUG_KMS(dev, "training pattern %d\n", tp);
nv_mask(dev, NV50_SOR_DP_CTRL(dp->or, dp->link), 0x0f000000, tp << 24);
auxch_tx(dev, dp->auxch, 9, DP_TRAINING_PATTERN_SET, &sink_tp, 1);
sink_tp &= ~DP_TRAINING_PATTERN_MASK;
sink_tp |= tp;
auxch_tx(dev, dp->auxch, 8, DP_TRAINING_PATTERN_SET, &sink_tp, 1);
}
static const u8 nv50_lane_map[] = { 16, 8, 0, 24 };
static const u8 nvaf_lane_map[] = { 24, 16, 8, 0 };
static int
dp_link_train_commit(struct drm_device *dev, struct dp_state *dp)
{
struct drm_nouveau_private *dev_priv = dev->dev_private;
u32 mask = 0, drv = 0, pre = 0, unk = 0;
const u8 *shifts;
int link = dp->link;
int or = dp->or;
int i;
if (dev_priv->chipset != 0xaf)
shifts = nv50_lane_map;
else
shifts = nvaf_lane_map;
for (i = 0; i < dp->link_nr; i++) {
u8 *conf = dp->entry + dp->table[4];
u8 lane = (dp->stat[4 + (i >> 1)] >> ((i & 1) * 4)) & 0xf;
u8 lpre = (lane & 0x0c) >> 2;
u8 lvsw = (lane & 0x03) >> 0;
mask |= 0xff << shifts[i];
unk |= 1 << (shifts[i] >> 3);
dp->conf[i] = (lpre << 3) | lvsw;
if (lvsw == DP_TRAIN_VOLTAGE_SWING_1200)
dp->conf[i] |= DP_TRAIN_MAX_SWING_REACHED;
if (lpre == DP_TRAIN_PRE_EMPHASIS_9_5)
dp->conf[i] |= DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
NV_DEBUG_KMS(dev, "config lane %d %02x\n", i, dp->conf[i]);
if (dp->table[0] < 0x30) {
u8 *last = conf + (dp->entry[4] * dp->table[5]);
while (lvsw != conf[0] || lpre != conf[1]) {
conf += dp->table[5];
if (conf >= last)
return -EINVAL;
}
conf += 2;
} else {
/* no lookup table anymore, set entries for each
* combination of voltage swing and pre-emphasis
* level allowed by the DP spec.
*/
switch (lvsw) {
case 0: lpre += 0; break;
case 1: lpre += 4; break;
case 2: lpre += 7; break;
case 3: lpre += 9; break;
}
conf = conf + (lpre * dp->table[5]);
conf++;
}
drv |= conf[0] << shifts[i];
pre |= conf[1] << shifts[i];
unk = (unk & ~0x0000ff00) | (conf[2] << 8);
}
nv_mask(dev, NV50_SOR_DP_UNK118(or, link), mask, drv);
nv_mask(dev, NV50_SOR_DP_UNK120(or, link), mask, pre);
nv_mask(dev, NV50_SOR_DP_UNK130(or, link), 0x0000ff0f, unk);
return auxch_tx(dev, dp->auxch, 8, DP_TRAINING_LANE0_SET, dp->conf, 4);
}
static int
dp_link_train_update(struct drm_device *dev, struct dp_state *dp, u32 delay)
{
int ret;
udelay(delay);
ret = auxch_tx(dev, dp->auxch, 9, DP_LANE0_1_STATUS, dp->stat, 6);
if (ret)
return ret;
NV_DEBUG_KMS(dev, "status %02x %02x %02x %02x %02x %02x\n",
dp->stat[0], dp->stat[1], dp->stat[2], dp->stat[3],
dp->stat[4], dp->stat[5]);
return 0;
}
static int
dp_link_train_cr(struct drm_device *dev, struct dp_state *dp)
{
bool cr_done = false, abort = false;
int voltage = dp->conf[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
int tries = 0, i;
dp_set_training_pattern(dev, dp, DP_TRAINING_PATTERN_1);
do {
if (dp_link_train_commit(dev, dp) ||
dp_link_train_update(dev, dp, 100))
break;
cr_done = true;
for (i = 0; i < dp->link_nr; i++) {
u8 lane = (dp->stat[i >> 1] >> ((i & 1) * 4)) & 0xf;
if (!(lane & DP_LANE_CR_DONE)) {
cr_done = false;
if (dp->conf[i] & DP_TRAIN_MAX_SWING_REACHED)
abort = true;
break;
}
}
if ((dp->conf[0] & DP_TRAIN_VOLTAGE_SWING_MASK) != voltage) {
voltage = dp->conf[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
tries = 0;
}
} while (!cr_done && !abort && ++tries < 5);
return cr_done ? 0 : -1;
}
static int
dp_link_train_eq(struct drm_device *dev, struct dp_state *dp)
{
bool eq_done, cr_done = true;
int tries = 0, i;
dp_set_training_pattern(dev, dp, DP_TRAINING_PATTERN_2);
do {
if (dp_link_train_update(dev, dp, 400))
break;
eq_done = !!(dp->stat[2] & DP_INTERLANE_ALIGN_DONE);
for (i = 0; i < dp->link_nr && eq_done; i++) {
u8 lane = (dp->stat[i >> 1] >> ((i & 1) * 4)) & 0xf;
if (!(lane & DP_LANE_CR_DONE))
cr_done = false;
if (!(lane & DP_LANE_CHANNEL_EQ_DONE) ||
!(lane & DP_LANE_SYMBOL_LOCKED))
eq_done = false;
}
if (dp_link_train_commit(dev, dp))
break;
} while (!eq_done && cr_done && ++tries <= 5);
return eq_done ? 0 : -1;
}
bool
nouveau_dp_link_train(struct drm_encoder *encoder, u32 datarate)
{
struct drm_nouveau_private *dev_priv = encoder->dev->dev_private;
struct nouveau_gpio_engine *pgpio = &dev_priv->engine.gpio;
struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
struct nouveau_crtc *nv_crtc = nouveau_crtc(encoder->crtc);
struct nouveau_connector *nv_connector =
nouveau_encoder_connector_get(nv_encoder);
struct drm_device *dev = encoder->dev;
struct nouveau_i2c_chan *auxch;
const u32 bw_list[] = { 270000, 162000, 0 };
const u32 *link_bw = bw_list;
struct dp_state dp;
auxch = nouveau_i2c_find(dev, nv_encoder->dcb->i2c_index);
if (!auxch)
return false;
dp.table = nouveau_dp_bios_data(dev, nv_encoder->dcb, &dp.entry);
if (!dp.table)
return -EINVAL;
dp.dcb = nv_encoder->dcb;
dp.crtc = nv_crtc->index;
dp.auxch = auxch->rd;
dp.or = nv_encoder->or;
dp.link = !(nv_encoder->dcb->sorconf.link & 1);
dp.dpcd = nv_encoder->dp.dpcd;
/* some sinks toggle hotplug in response to some of the actions
* we take during link training (DP_SET_POWER is one), we need
* to ignore them for the moment to avoid races.
*/
pgpio->irq_enable(dev, nv_connector->dcb->gpio_tag, false);
/* enable down-spreading, if possible */
if (dp.table[1] >= 16) {
u16 script = ROM16(dp.entry[14]);
if (nv_encoder->dp.dpcd[3] & 1)
script = ROM16(dp.entry[12]);
nouveau_bios_run_init_table(dev, script, dp.dcb, dp.crtc);
}
/* execute pre-train script from vbios */
nouveau_bios_run_init_table(dev, ROM16(dp.entry[6]), dp.dcb, dp.crtc);
/* start off at highest link rate supported by encoder and display */
while (*link_bw > nv_encoder->dp.link_bw)
link_bw++;
while (link_bw[0]) {
/* find minimum required lane count at this link rate */
dp.link_nr = nv_encoder->dp.link_nr;
while ((dp.link_nr >> 1) * link_bw[0] > datarate)
dp.link_nr >>= 1;
/* drop link rate to minimum with this lane count */
while ((link_bw[1] * dp.link_nr) > datarate)
link_bw++;
dp.link_bw = link_bw[0];
/* program selected link configuration */
dp_set_link_config(dev, &dp);
/* attempt to train the link at this configuration */
memset(dp.stat, 0x00, sizeof(dp.stat));
if (!dp_link_train_cr(dev, &dp) &&
!dp_link_train_eq(dev, &dp))
break;
/* retry at lower rate */
link_bw++;
}
/* finish link training */
dp_set_training_pattern(dev, &dp, DP_TRAINING_PATTERN_DISABLE);
/* execute post-train script from vbios */
nouveau_bios_run_init_table(dev, ROM16(dp.entry[8]), dp.dcb, dp.crtc);
/* re-enable hotplug detect */
pgpio->irq_enable(dev, nv_connector->dcb->gpio_tag, true);
return true;
}
bool
nouveau_dp_detect(struct drm_encoder *encoder)
{
struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
struct drm_device *dev = encoder->dev;
struct nouveau_i2c_chan *auxch;
u8 *dpcd = nv_encoder->dp.dpcd;
int ret;
auxch = nouveau_i2c_find(dev, nv_encoder->dcb->i2c_index);
if (!auxch)
return false;
ret = auxch_tx(dev, auxch->rd, 9, DP_DPCD_REV, dpcd, 8);
if (ret)
return false;
nv_encoder->dp.link_bw = 27000 * dpcd[1];
nv_encoder->dp.link_nr = dpcd[2] & DP_MAX_LANE_COUNT_MASK;
NV_DEBUG_KMS(dev, "display: %dx%d dpcd 0x%02x\n",
nv_encoder->dp.link_nr, nv_encoder->dp.link_bw, dpcd[0]);
NV_DEBUG_KMS(dev, "encoder: %dx%d\n",
nv_encoder->dcb->dpconf.link_nr,
nv_encoder->dcb->dpconf.link_bw);
if (nv_encoder->dcb->dpconf.link_nr < nv_encoder->dp.link_nr)
nv_encoder->dp.link_nr = nv_encoder->dcb->dpconf.link_nr;
if (nv_encoder->dcb->dpconf.link_bw < nv_encoder->dp.link_bw)
nv_encoder->dp.link_bw = nv_encoder->dcb->dpconf.link_bw;
NV_DEBUG_KMS(dev, "maximum: %dx%d\n",
nv_encoder->dp.link_nr, nv_encoder->dp.link_bw);
return true;
}
int
nouveau_dp_auxch(struct nouveau_i2c_chan *auxch, int cmd, int addr,
uint8_t *data, int data_nr)
{
return auxch_tx(auxch->dev, auxch->rd, cmd, addr, data, data_nr);
}
static int
nouveau_dp_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
struct nouveau_i2c_chan *auxch = (struct nouveau_i2c_chan *)adap;
struct i2c_msg *msg = msgs;
int ret, mcnt = num;
while (mcnt--) {
u8 remaining = msg->len;
u8 *ptr = msg->buf;
while (remaining) {
u8 cnt = (remaining > 16) ? 16 : remaining;
u8 cmd;
if (msg->flags & I2C_M_RD)
cmd = AUX_I2C_READ;
else
cmd = AUX_I2C_WRITE;
if (mcnt || remaining > 16)
cmd |= AUX_I2C_MOT;
ret = nouveau_dp_auxch(auxch, cmd, msg->addr, ptr, cnt);
if (ret < 0)
return ret;
ptr += cnt;
remaining -= cnt;
}
msg++;
}
return num;
}
static u32
nouveau_dp_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
const struct i2c_algorithm nouveau_dp_i2c_algo = {
.master_xfer = nouveau_dp_i2c_xfer,
.functionality = nouveau_dp_i2c_func
};