drm_dp_helper.h revision 254817
1294113Sbapt/*
2241675Suqs * Copyright �� 2008 Keith Packard
3241675Suqs *
4294113Sbapt * Permission to use, copy, modify, distribute, and sell this software and its
5241675Suqs * documentation for any purpose is hereby granted without fee, provided that
6241675Suqs * the above copyright notice appear in all copies and that both that copyright
7241675Suqs * notice and this permission notice appear in supporting documentation, and
8241675Suqs * that the name of the copyright holders not be used in advertising or
9241675Suqs * publicity pertaining to distribution of the software without specific,
10294113Sbapt * written prior permission.  The copyright holders make no representations
11241675Suqs * about the suitability of this software for any purpose.  It is provided "as
12294113Sbapt * is" without express or implied warranty.
13241675Suqs *
14241675Suqs * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15241675Suqs * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16241675Suqs * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17241675Suqs * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18241675Suqs * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19241675Suqs * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
20241675Suqs * OF THIS SOFTWARE.
21241675Suqs *
22275432Sbapt * $FreeBSD: head/sys/dev/drm2/drm_dp_helper.h 254817 2013-08-24 23:38:57Z dumbbell $
23275432Sbapt */
24275432Sbapt
25241675Suqs#ifndef _DRM_DP_HELPER_H_
26241675Suqs#define _DRM_DP_HELPER_H_
27241675Suqs
28241675Suqs/*
29241675Suqs * Unless otherwise noted, all values are from the DP 1.1a spec.  Note that
30275432Sbapt * DP and DPCD versions are independent.  Differences from 1.0 are not noted,
31275432Sbapt * 1.0 devices basically don't exist in the wild.
32241675Suqs *
33241675Suqs * Abbreviations, in chronological order:
34241675Suqs *
35274880Sbapt * eDP: Embedded DisplayPort version 1
36241675Suqs * DPI: DisplayPort Interoperability Guideline v1.1a
37241675Suqs * 1.2: DisplayPort 1.2
38294113Sbapt *
39241675Suqs * 1.2 formally includes both eDP and DPI definitions.
40241675Suqs */
41294113Sbapt
42294113Sbapt#define AUX_NATIVE_WRITE	0x8
43241675Suqs#define AUX_NATIVE_READ		0x9
44241675Suqs#define AUX_I2C_WRITE		0x0
45241675Suqs#define AUX_I2C_READ		0x1
46241675Suqs#define AUX_I2C_STATUS		0x2
47241675Suqs#define AUX_I2C_MOT		0x4
48241675Suqs
49241675Suqs#define AUX_NATIVE_REPLY_ACK	(0x0 << 4)
50294113Sbapt#define AUX_NATIVE_REPLY_NACK	(0x1 << 4)
51241675Suqs#define AUX_NATIVE_REPLY_DEFER	(0x2 << 4)
52275432Sbapt#define AUX_NATIVE_REPLY_MASK	(0x3 << 4)
53241675Suqs
54241675Suqs#define AUX_I2C_REPLY_ACK	(0x0 << 6)
55241675Suqs#define AUX_I2C_REPLY_NACK	(0x1 << 6)
56241675Suqs#define AUX_I2C_REPLY_DEFER	(0x2 << 6)
57241675Suqs#define AUX_I2C_REPLY_MASK	(0x3 << 6)
58241675Suqs
59274880Sbapt/* AUX CH addresses */
60241675Suqs/* DPCD */
61294113Sbapt#define DP_DPCD_REV                         0x000
62241675Suqs
63294113Sbapt#define DP_MAX_LINK_RATE                    0x001
64241675Suqs
65294113Sbapt#define DP_MAX_LANE_COUNT                   0x002
66241675Suqs# define DP_MAX_LANE_COUNT_MASK		    0x1f
67241675Suqs# define DP_TPS3_SUPPORTED		    (1 << 6) /* 1.2 */
68241675Suqs# define DP_ENHANCED_FRAME_CAP		    (1 << 7)
69241675Suqs
70294113Sbapt#define DP_MAX_DOWNSPREAD                   0x003
71241675Suqs# define DP_NO_AUX_HANDSHAKE_LINK_TRAINING  (1 << 6)
72274880Sbapt
73279527Sbapt#define DP_NORP                             0x004
74279527Sbapt
75279527Sbapt#define DP_DOWNSTREAMPORT_PRESENT           0x005
76241675Suqs# define DP_DWN_STRM_PORT_PRESENT           (1 << 0)
77241675Suqs# define DP_DWN_STRM_PORT_TYPE_MASK         0x06
78241675Suqs/* 00b = DisplayPort */
79241675Suqs/* 01b = Analog */
80241675Suqs/* 10b = TMDS or HDMI */
81241675Suqs/* 11b = Other */
82241675Suqs# define DP_FORMAT_CONVERSION               (1 << 3)
83241675Suqs# define DP_DETAILED_CAP_INFO_AVAILABLE	    (1 << 4) /* DPI */
84241675Suqs
85241675Suqs#define DP_MAIN_LINK_CHANNEL_CODING         0x006
86274880Sbapt
87241675Suqs#define DP_DOWN_STREAM_PORT_COUNT	    0x007
88241675Suqs# define DP_PORT_COUNT_MASK		    0x0f
89275432Sbapt# define DP_MSA_TIMING_PAR_IGNORED	    (1 << 6) /* eDP */
90241675Suqs# define DP_OUI_SUPPORT			    (1 << 7)
91294113Sbapt
92294113Sbapt#define DP_I2C_SPEED_CAP		    0x00c    /* DPI */
93294113Sbapt# define DP_I2C_SPEED_1K		    0x01
94294113Sbapt# define DP_I2C_SPEED_5K		    0x02
95294113Sbapt# define DP_I2C_SPEED_10K		    0x04
96294113Sbapt# define DP_I2C_SPEED_100K		    0x08
97294113Sbapt# define DP_I2C_SPEED_400K		    0x10
98294113Sbapt# define DP_I2C_SPEED_1M		    0x20
99241675Suqs
100294113Sbapt#define DP_EDP_CONFIGURATION_CAP            0x00d   /* XXX 1.2? */
101274880Sbapt#define DP_TRAINING_AUX_RD_INTERVAL         0x00e   /* XXX 1.2? */
102241675Suqs
103241675Suqs/* Multiple stream transport */
104241675Suqs#define DP_MSTM_CAP			    0x021   /* 1.2 */
105241675Suqs# define DP_MST_CAP			    (1 << 0)
106241675Suqs
107241675Suqs#define DP_PSR_SUPPORT                      0x070   /* XXX 1.2? */
108241675Suqs# define DP_PSR_IS_SUPPORTED                1
109241675Suqs#define DP_PSR_CAPS                         0x071   /* XXX 1.2? */
110241675Suqs# define DP_PSR_NO_TRAIN_ON_EXIT            1
111241675Suqs# define DP_PSR_SETUP_TIME_330              (0 << 1)
112294113Sbapt# define DP_PSR_SETUP_TIME_275              (1 << 1)
113294113Sbapt# define DP_PSR_SETUP_TIME_220              (2 << 1)
114294113Sbapt# define DP_PSR_SETUP_TIME_165              (3 << 1)
115294113Sbapt# define DP_PSR_SETUP_TIME_110              (4 << 1)
116294113Sbapt# define DP_PSR_SETUP_TIME_55               (5 << 1)
117294113Sbapt# define DP_PSR_SETUP_TIME_0                (6 << 1)
118294113Sbapt# define DP_PSR_SETUP_TIME_MASK             (7 << 1)
119294113Sbapt# define DP_PSR_SETUP_TIME_SHIFT            1
120294113Sbapt
121294113Sbapt/*
122241675Suqs * 0x80-0x8f describe downstream port capabilities, but there are two layouts
123294113Sbapt * based on whether DP_DETAILED_CAP_INFO_AVAILABLE was set.  If it was not,
124241675Suqs * each port's descriptor is one byte wide.  If it was set, each port's is
125241675Suqs * four bytes wide, starting with the one byte from the base info.  As of
126241675Suqs * DP interop v1.1a only VGA defines additional detail.
127294113Sbapt */
128241675Suqs
129241675Suqs/* offset 0 */
130294113Sbapt#define DP_DOWNSTREAM_PORT_0		    0x80
131241675Suqs# define DP_DS_PORT_TYPE_MASK		    (7 << 0)
132241675Suqs# define DP_DS_PORT_TYPE_DP		    0
133241675Suqs# define DP_DS_PORT_TYPE_VGA		    1
134294113Sbapt# define DP_DS_PORT_TYPE_DVI		    2
135241675Suqs# define DP_DS_PORT_TYPE_HDMI		    3
136241675Suqs# define DP_DS_PORT_TYPE_NON_EDID	    4
137294113Sbapt# define DP_DS_PORT_HPD			    (1 << 3)
138241675Suqs/* offset 1 for VGA is maximum megapixels per second / 8 */
139241675Suqs/* offset 2 */
140241675Suqs# define DP_DS_VGA_MAX_BPC_MASK		    (3 << 0)
141294113Sbapt# define DP_DS_VGA_8BPC			    0
142241675Suqs# define DP_DS_VGA_10BPC		    1
143241675Suqs# define DP_DS_VGA_12BPC		    2
144294113Sbapt# define DP_DS_VGA_16BPC		    3
145241675Suqs
146241675Suqs/* link configuration */
147274880Sbapt#define	DP_LINK_BW_SET		            0x100
148294113Sbapt# define DP_LINK_BW_1_62		    0x06
149274880Sbapt# define DP_LINK_BW_2_7			    0x0a
150274880Sbapt# define DP_LINK_BW_5_4			    0x14    /* 1.2 */
151294113Sbapt
152274880Sbapt#define DP_LANE_COUNT_SET	            0x101
153275432Sbapt# define DP_LANE_COUNT_MASK		    0x0f
154274880Sbapt# define DP_LANE_COUNT_ENHANCED_FRAME_EN    (1 << 7)
155275432Sbapt
156294113Sbapt#define DP_TRAINING_PATTERN_SET	            0x102
157294113Sbapt# define DP_TRAINING_PATTERN_DISABLE	    0
158274880Sbapt# define DP_TRAINING_PATTERN_1		    1
159274880Sbapt# define DP_TRAINING_PATTERN_2		    2
160275432Sbapt# define DP_TRAINING_PATTERN_3		    3	    /* 1.2 */
161274880Sbapt# define DP_TRAINING_PATTERN_MASK	    0x3
162274880Sbapt
163274880Sbapt# define DP_LINK_QUAL_PATTERN_DISABLE	    (0 << 2)
164274880Sbapt# define DP_LINK_QUAL_PATTERN_D10_2	    (1 << 2)
165279527Sbapt# define DP_LINK_QUAL_PATTERN_ERROR_RATE    (2 << 2)
166279527Sbapt# define DP_LINK_QUAL_PATTERN_PRBS7	    (3 << 2)
167279527Sbapt# define DP_LINK_QUAL_PATTERN_MASK	    (3 << 2)
168279527Sbapt
169279527Sbapt# define DP_RECOVERED_CLOCK_OUT_EN	    (1 << 4)
170279527Sbapt# define DP_LINK_SCRAMBLING_DISABLE	    (1 << 5)
171279527Sbapt
172294113Sbapt# define DP_SYMBOL_ERROR_COUNT_BOTH	    (0 << 6)
173279527Sbapt# define DP_SYMBOL_ERROR_COUNT_DISPARITY    (1 << 6)
174279527Sbapt# define DP_SYMBOL_ERROR_COUNT_SYMBOL	    (2 << 6)
175279527Sbapt# define DP_SYMBOL_ERROR_COUNT_MASK	    (3 << 6)
176279527Sbapt
177279527Sbapt#define DP_TRAINING_LANE0_SET		    0x103
178279527Sbapt#define DP_TRAINING_LANE1_SET		    0x104
179279527Sbapt#define DP_TRAINING_LANE2_SET		    0x105
180241675Suqs#define DP_TRAINING_LANE3_SET		    0x106
181241675Suqs
182241675Suqs# define DP_TRAIN_VOLTAGE_SWING_MASK	    0x3
183241675Suqs# define DP_TRAIN_VOLTAGE_SWING_SHIFT	    0
184294113Sbapt# define DP_TRAIN_MAX_SWING_REACHED	    (1 << 2)
185241675Suqs# define DP_TRAIN_VOLTAGE_SWING_400	    (0 << 0)
186241675Suqs# define DP_TRAIN_VOLTAGE_SWING_600	    (1 << 0)
187241675Suqs# define DP_TRAIN_VOLTAGE_SWING_800	    (2 << 0)
188241675Suqs# define DP_TRAIN_VOLTAGE_SWING_1200	    (3 << 0)
189241675Suqs
190241675Suqs# define DP_TRAIN_PRE_EMPHASIS_MASK	    (3 << 3)
191241675Suqs# define DP_TRAIN_PRE_EMPHASIS_0	    (0 << 3)
192241675Suqs# define DP_TRAIN_PRE_EMPHASIS_3_5	    (1 << 3)
193241675Suqs# define DP_TRAIN_PRE_EMPHASIS_6	    (2 << 3)
194241675Suqs# define DP_TRAIN_PRE_EMPHASIS_9_5	    (3 << 3)
195241675Suqs
196241675Suqs# define DP_TRAIN_PRE_EMPHASIS_SHIFT	    3
197274880Sbapt# define DP_TRAIN_MAX_PRE_EMPHASIS_REACHED  (1 << 5)
198241675Suqs
199241675Suqs#define DP_DOWNSPREAD_CTRL		    0x107
200241675Suqs# define DP_SPREAD_AMP_0_5		    (1 << 4)
201241675Suqs# define DP_MSA_TIMING_PAR_IGNORE_EN	    (1 << 7) /* eDP */
202241675Suqs
203241675Suqs#define DP_MAIN_LINK_CHANNEL_CODING_SET	    0x108
204241675Suqs# define DP_SET_ANSI_8B10B		    (1 << 0)
205241675Suqs
206241675Suqs#define DP_I2C_SPEED_CONTROL_STATUS	    0x109   /* DPI */
207241675Suqs/* bitmask as for DP_I2C_SPEED_CAP */
208241675Suqs
209241675Suqs#define DP_EDP_CONFIGURATION_SET            0x10a   /* XXX 1.2? */
210241675Suqs
211241675Suqs#define DP_MSTM_CTRL			    0x111   /* 1.2 */
212241675Suqs# define DP_MST_EN			    (1 << 0)
213241675Suqs# define DP_UP_REQ_EN			    (1 << 1)
214241675Suqs# define DP_UPSTREAM_IS_SRC		    (1 << 2)
215241675Suqs
216241675Suqs#define DP_PSR_EN_CFG			    0x170   /* XXX 1.2? */
217241675Suqs# define DP_PSR_ENABLE			    (1 << 0)
218241675Suqs# define DP_PSR_MAIN_LINK_ACTIVE	    (1 << 1)
219294113Sbapt# define DP_PSR_CRC_VERIFICATION	    (1 << 2)
220241675Suqs# define DP_PSR_FRAME_CAPTURE		    (1 << 3)
221241675Suqs
222241675Suqs#define DP_SINK_COUNT			    0x200
223241675Suqs/* prior to 1.2 bit 7 was reserved mbz */
224241675Suqs# define DP_GET_SINK_COUNT(x)		    ((((x) & 0x80) >> 1) | ((x) & 0x3f))
225241675Suqs# define DP_SINK_CP_READY		    (1 << 6)
226274880Sbapt
227241675Suqs#define DP_DEVICE_SERVICE_IRQ_VECTOR	    0x201
228241675Suqs# define DP_REMOTE_CONTROL_COMMAND_PENDING  (1 << 0)
229241675Suqs# define DP_AUTOMATED_TEST_REQUEST	    (1 << 1)
230241675Suqs# define DP_CP_IRQ			    (1 << 2)
231241675Suqs# define DP_SINK_SPECIFIC_IRQ		    (1 << 6)
232294113Sbapt
233241675Suqs#define DP_LANE0_1_STATUS		    0x202
234241675Suqs#define DP_LANE2_3_STATUS		    0x203
235241675Suqs# define DP_LANE_CR_DONE		    (1 << 0)
236241675Suqs# define DP_LANE_CHANNEL_EQ_DONE	    (1 << 1)
237241675Suqs# define DP_LANE_SYMBOL_LOCKED		    (1 << 2)
238275432Sbapt
239294113Sbapt#define DP_CHANNEL_EQ_BITS (DP_LANE_CR_DONE |		\
240275432Sbapt			    DP_LANE_CHANNEL_EQ_DONE |	\
241274880Sbapt			    DP_LANE_SYMBOL_LOCKED)
242294113Sbapt
243241675Suqs#define DP_LANE_ALIGN_STATUS_UPDATED	    0x204
244275432Sbapt
245294113Sbapt#define DP_INTERLANE_ALIGN_DONE		    (1 << 0)
246275432Sbapt#define DP_DOWNSTREAM_PORT_STATUS_CHANGED   (1 << 6)
247274880Sbapt#define DP_LINK_STATUS_UPDATED		    (1 << 7)
248294113Sbapt
249241675Suqs#define DP_SINK_STATUS			    0x205
250275432Sbapt
251294113Sbapt#define DP_RECEIVE_PORT_0_STATUS	    (1 << 0)
252275432Sbapt#define DP_RECEIVE_PORT_1_STATUS	    (1 << 1)
253294113Sbapt
254274880Sbapt#define DP_ADJUST_REQUEST_LANE0_1	    0x206
255294113Sbapt#define DP_ADJUST_REQUEST_LANE2_3	    0x207
256241675Suqs# define DP_ADJUST_VOLTAGE_SWING_LANE0_MASK  0x03
257274880Sbapt# define DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT 0
258294113Sbapt# define DP_ADJUST_PRE_EMPHASIS_LANE0_MASK   0x0c
259241675Suqs# define DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT  2
260275432Sbapt# define DP_ADJUST_VOLTAGE_SWING_LANE1_MASK  0x30
261275432Sbapt# define DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT 4
262294113Sbapt# define DP_ADJUST_PRE_EMPHASIS_LANE1_MASK   0xc0
263241675Suqs# define DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT  6
264275432Sbapt
265275432Sbapt#define DP_TEST_REQUEST			    0x218
266241675Suqs# define DP_TEST_LINK_TRAINING		    (1 << 0)
267294113Sbapt# define DP_TEST_LINK_PATTERN		    (1 << 1)
268241675Suqs# define DP_TEST_LINK_EDID_READ		    (1 << 2)
269241675Suqs# define DP_TEST_LINK_PHY_TEST_PATTERN	    (1 << 3) /* DPCD >= 1.1 */
270275432Sbapt
271275432Sbapt#define DP_TEST_LINK_RATE		    0x219
272275432Sbapt# define DP_LINK_RATE_162		    (0x6)
273275432Sbapt# define DP_LINK_RATE_27		    (0xa)
274275432Sbapt
275275432Sbapt#define DP_TEST_LANE_COUNT		    0x220
276275432Sbapt
277275432Sbapt#define DP_TEST_PATTERN			    0x221
278275432Sbapt
279275432Sbapt#define DP_TEST_RESPONSE		    0x260
280275432Sbapt# define DP_TEST_ACK			    (1 << 0)
281275432Sbapt# define DP_TEST_NAK			    (1 << 1)
282275432Sbapt# define DP_TEST_EDID_CHECKSUM_WRITE	    (1 << 2)
283275432Sbapt
284275432Sbapt#define DP_SOURCE_OUI			    0x300
285275432Sbapt#define DP_SINK_OUI			    0x400
286275432Sbapt#define DP_BRANCH_OUI			    0x500
287275432Sbapt
288275432Sbapt#define DP_SET_POWER                        0x600
289275432Sbapt# define DP_SET_POWER_D0                    0x1
290275432Sbapt# define DP_SET_POWER_D3                    0x2
291275432Sbapt
292275432Sbapt#define DP_PSR_ERROR_STATUS                 0x2006  /* XXX 1.2? */
293275432Sbapt# define DP_PSR_LINK_CRC_ERROR              (1 << 0)
294275432Sbapt# define DP_PSR_RFB_STORAGE_ERROR           (1 << 1)
295275432Sbapt
296275432Sbapt#define DP_PSR_ESI                          0x2007  /* XXX 1.2? */
297275432Sbapt# define DP_PSR_CAPS_CHANGE                 (1 << 0)
298275432Sbapt
299275432Sbapt#define DP_PSR_STATUS                       0x2008  /* XXX 1.2? */
300275432Sbapt# define DP_PSR_SINK_INACTIVE               0
301275432Sbapt# define DP_PSR_SINK_ACTIVE_SRC_SYNCED      1
302275432Sbapt# define DP_PSR_SINK_ACTIVE_RFB             2
303275432Sbapt# define DP_PSR_SINK_ACTIVE_SINK_SYNCED     3
304275432Sbapt# define DP_PSR_SINK_ACTIVE_RESYNC          4
305275432Sbapt# define DP_PSR_SINK_INTERNAL_ERROR         7
306275432Sbapt# define DP_PSR_SINK_STATE_MASK             0x07
307275432Sbapt
308275432Sbapt#define MODE_I2C_START	1
309275432Sbapt#define MODE_I2C_WRITE	2
310275432Sbapt#define MODE_I2C_READ	4
311275432Sbapt#define MODE_I2C_STOP	8
312275432Sbapt
313275432Sbaptstruct iic_dp_aux_data {
314275432Sbapt	bool running;
315275432Sbapt	u16 address;
316275432Sbapt	void *priv;
317275432Sbapt	int (*aux_ch)(device_t adapter, int mode, uint8_t write_byte,
318275432Sbapt	    uint8_t *read_byte);
319275432Sbapt	device_t port;
320275432Sbapt};
321275432Sbapt
322275432Sbaptint iic_dp_aux_add_bus(device_t dev, const char *name,
323275432Sbapt    int (*ch)(device_t idev, int mode, uint8_t write_byte, uint8_t *read_byte),
324275432Sbapt    void *priv, device_t *bus, device_t *adapter);
325275432Sbapt
326275432Sbapt
327275432Sbapt#define DP_LINK_STATUS_SIZE	   6
328275432Sbaptbool drm_dp_channel_eq_ok(u8 link_status[DP_LINK_STATUS_SIZE],
329275432Sbapt			  int lane_count);
330275432Sbaptbool drm_dp_clock_recovery_ok(u8 link_status[DP_LINK_STATUS_SIZE],
331275432Sbapt			      int lane_count);
332275432Sbaptu8 drm_dp_get_adjust_request_voltage(u8 link_status[DP_LINK_STATUS_SIZE],
333275432Sbapt				     int lane);
334275432Sbaptu8 drm_dp_get_adjust_request_pre_emphasis(u8 link_status[DP_LINK_STATUS_SIZE],
335275432Sbapt					  int lane);
336275432Sbapt
337275432Sbapt#define DP_RECEIVER_CAP_SIZE	0xf
338275432Sbaptvoid drm_dp_link_train_clock_recovery_delay(u8 dpcd[DP_RECEIVER_CAP_SIZE]);
339275432Sbaptvoid drm_dp_link_train_channel_eq_delay(u8 dpcd[DP_RECEIVER_CAP_SIZE]);
340275432Sbapt
341275432Sbaptu8 drm_dp_link_rate_to_bw_code(int link_rate);
342294113Sbaptint drm_dp_bw_code_to_link_rate(u8 link_bw);
343294113Sbapt
344275432Sbaptstatic inline int
345275432Sbaptdrm_dp_max_link_rate(u8 dpcd[DP_RECEIVER_CAP_SIZE])
346275432Sbapt{
347241675Suqs	return drm_dp_bw_code_to_link_rate(dpcd[DP_MAX_LINK_RATE]);
348241675Suqs}
349241675Suqs
350241675Suqsstatic inline u8
351241675Suqsdrm_dp_max_lane_count(u8 dpcd[DP_RECEIVER_CAP_SIZE])
352274880Sbapt{
353274880Sbapt	return dpcd[DP_MAX_LANE_COUNT] & DP_MAX_LANE_COUNT_MASK;
354274880Sbapt}
355274880Sbapt
356274880Sbapt#endif /* _DRM_DP_HELPER_H_ */
357294113Sbapt