2 * Copyright © 2016 Intel Corporation
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20 * OTHER DEALINGS IN THE SOFTWARE.
23 #include <linux/errno.h>
24 #include <linux/export.h>
25 #include <linux/i2c.h>
26 #include <linux/slab.h>
27 #include <linux/string.h>
28 #include <drm/drm_dp_dual_mode_helper.h>
32 * DOC: dp dual mode helpers
34 * Helper functions to deal with DP dual mode (aka. DP++) adaptors.
37 * Adaptor registers (if any) and the sink DDC bus may be accessed via I2C.
40 * Adaptor registers and sink DDC bus can be accessed either via I2C or
41 * I2C-over-AUX. Source devices may choose to implement either of these
45 #define DP_DUAL_MODE_SLAVE_ADDRESS 0x40
48 * drm_dp_dual_mode_read - Read from the DP dual mode adaptor register(s)
49 * @adapter: I2C adapter for the DDC bus
50 * @offset: register offset
51 * @buffer: buffer for return data
52 * @size: sizo of the buffer
54 * Reads @size bytes from the DP dual mode adaptor registers
55 * starting at @offset.
58 * 0 on success, negative error code on failure
60 ssize_t
drm_dp_dual_mode_read(struct i2c_adapter
*adapter
,
61 u8 offset
, void *buffer
, size_t size
)
63 struct i2c_msg msgs
[] = {
65 .addr
= DP_DUAL_MODE_SLAVE_ADDRESS
,
71 .addr
= DP_DUAL_MODE_SLAVE_ADDRESS
,
79 ret
= i2c_transfer(adapter
, msgs
, ARRAY_SIZE(msgs
));
82 if (ret
!= ARRAY_SIZE(msgs
))
87 EXPORT_SYMBOL(drm_dp_dual_mode_read
);
90 * drm_dp_dual_mode_write - Write to the DP dual mode adaptor register(s)
91 * @adapter: I2C adapter for the DDC bus
92 * @offset: register offset
93 * @buffer: buffer for write data
94 * @size: sizo of the buffer
96 * Writes @size bytes to the DP dual mode adaptor registers
97 * starting at @offset.
100 * 0 on success, negative error code on failure
102 ssize_t
drm_dp_dual_mode_write(struct i2c_adapter
*adapter
,
103 u8 offset
, const void *buffer
, size_t size
)
105 struct i2c_msg msg
= {
106 .addr
= DP_DUAL_MODE_SLAVE_ADDRESS
,
114 data
= kmalloc(msg
.len
, M_DRM
, GFP_KERNEL
);
120 memcpy(data
, &offset
, 1);
121 memcpy(data
+ 1, buffer
, size
);
123 ret
= i2c_transfer(adapter
, &msg
, 1);
134 EXPORT_SYMBOL(drm_dp_dual_mode_write
);
136 static bool is_hdmi_adaptor(const char hdmi_id
[DP_DUAL_MODE_HDMI_ID_LEN
])
138 static const char dp_dual_mode_hdmi_id
[DP_DUAL_MODE_HDMI_ID_LEN
] =
139 "DP-HDMI ADAPTOR\x04";
141 return memcmp(hdmi_id
, dp_dual_mode_hdmi_id
,
142 sizeof(dp_dual_mode_hdmi_id
)) == 0;
145 static bool is_type1_adaptor(uint8_t adaptor_id
)
147 return adaptor_id
== 0 || adaptor_id
== 0xff;
150 static bool is_type2_adaptor(uint8_t adaptor_id
)
152 return adaptor_id
== (DP_DUAL_MODE_TYPE_TYPE2
|
153 DP_DUAL_MODE_REV_TYPE2
);
156 static bool is_lspcon_adaptor(const char hdmi_id
[DP_DUAL_MODE_HDMI_ID_LEN
],
157 const uint8_t adaptor_id
)
159 return is_hdmi_adaptor(hdmi_id
) &&
160 (adaptor_id
== (DP_DUAL_MODE_TYPE_TYPE2
|
161 DP_DUAL_MODE_TYPE_HAS_DPCD
));
165 * drm_dp_dual_mode_detect - Identify the DP dual mode adaptor
166 * @adapter: I2C adapter for the DDC bus
168 * Attempt to identify the type of the DP dual mode adaptor used.
170 * Note that when the answer is @DRM_DP_DUAL_MODE_UNKNOWN it's not
171 * certain whether we're dealing with a native HDMI port or
172 * a type 1 DVI dual mode adaptor. The driver will have to use
173 * some other hardware/driver specific mechanism to make that
177 * The type of the DP dual mode adaptor used
179 enum drm_dp_dual_mode_type
drm_dp_dual_mode_detect(struct i2c_adapter
*adapter
)
181 char hdmi_id
[DP_DUAL_MODE_HDMI_ID_LEN
] = {};
182 uint8_t adaptor_id
= 0x00;
186 * Let's see if the adaptor is there the by reading the
189 * Note that type 1 DVI adaptors are not required to implemnt
190 * any registers, and that presents a problem for detection.
191 * If the i2c transfer is nacked, we may or may not be dealing
192 * with a type 1 DVI adaptor. Some other mechanism of detecting
193 * the presence of the adaptor is required. One way would be
194 * to check the state of the CONFIG1 pin, Another method would
195 * simply require the driver to know whether the port is a DP++
196 * port or a native HDMI port. Both of these methods are entirely
197 * hardware/driver specific so we can't deal with them here.
199 ret
= drm_dp_dual_mode_read(adapter
, DP_DUAL_MODE_HDMI_ID
,
200 hdmi_id
, sizeof(hdmi_id
));
201 DRM_DEBUG_KMS("DP dual mode HDMI ID: %*pE (err %zd)\n",
202 ret
? 0 : (int)sizeof(hdmi_id
), hdmi_id
, ret
);
204 return DRM_DP_DUAL_MODE_UNKNOWN
;
207 * Sigh. Some (maybe all?) type 1 adaptors are broken and ack
208 * the offset but ignore it, and instead they just always return
209 * data from the start of the HDMI ID buffer. So for a broken
210 * type 1 HDMI adaptor a single byte read will always give us
211 * 0x44, and for a type 1 DVI adaptor it should give 0x00
212 * (assuming it implements any registers). Fortunately neither
213 * of those values will match the type 2 signature of the
214 * DP_DUAL_MODE_ADAPTOR_ID register so we can proceed with
215 * the type 2 adaptor detection safely even in the presence
216 * of broken type 1 adaptors.
218 ret
= drm_dp_dual_mode_read(adapter
, DP_DUAL_MODE_ADAPTOR_ID
,
219 &adaptor_id
, sizeof(adaptor_id
));
220 DRM_DEBUG_KMS("DP dual mode adaptor ID: %02x (err %zd)\n",
223 if (is_lspcon_adaptor(hdmi_id
, adaptor_id
))
224 return DRM_DP_DUAL_MODE_LSPCON
;
225 if (is_type2_adaptor(adaptor_id
)) {
226 if (is_hdmi_adaptor(hdmi_id
))
227 return DRM_DP_DUAL_MODE_TYPE2_HDMI
;
229 return DRM_DP_DUAL_MODE_TYPE2_DVI
;
232 * If neither a proper type 1 ID nor a broken type 1 adaptor
233 * as described above, assume type 1, but let the user know
234 * that we may have misdetected the type.
236 if (!is_type1_adaptor(adaptor_id
) && adaptor_id
!= hdmi_id
[0])
237 DRM_ERROR("Unexpected DP dual mode adaptor ID %02x\n",
242 if (is_hdmi_adaptor(hdmi_id
))
243 return DRM_DP_DUAL_MODE_TYPE1_HDMI
;
245 return DRM_DP_DUAL_MODE_TYPE1_DVI
;
247 EXPORT_SYMBOL(drm_dp_dual_mode_detect
);
250 * drm_dp_dual_mode_max_tmds_clock - Max TMDS clock for DP dual mode adaptor
251 * @type: DP dual mode adaptor type
252 * @adapter: I2C adapter for the DDC bus
254 * Determine the max TMDS clock the adaptor supports based on the
255 * type of the dual mode adaptor and the DP_DUAL_MODE_MAX_TMDS_CLOCK
256 * register (on type2 adaptors). As some type 1 adaptors have
257 * problems with registers (see comments in drm_dp_dual_mode_detect())
258 * we don't read the register on those, instead we simply assume
259 * a 165 MHz limit based on the specification.
262 * Maximum supported TMDS clock rate for the DP dual mode adaptor in kHz.
264 int drm_dp_dual_mode_max_tmds_clock(enum drm_dp_dual_mode_type type
,
265 struct i2c_adapter
*adapter
)
267 uint8_t max_tmds_clock
;
270 /* native HDMI so no limit */
271 if (type
== DRM_DP_DUAL_MODE_NONE
)
275 * Type 1 adaptors are limited to 165MHz
276 * Type 2 adaptors can tells us their limit
278 if (type
< DRM_DP_DUAL_MODE_TYPE2_DVI
)
281 ret
= drm_dp_dual_mode_read(adapter
, DP_DUAL_MODE_MAX_TMDS_CLOCK
,
282 &max_tmds_clock
, sizeof(max_tmds_clock
));
283 if (ret
|| max_tmds_clock
== 0x00 || max_tmds_clock
== 0xff) {
284 DRM_DEBUG_KMS("Failed to query max TMDS clock\n");
288 return max_tmds_clock
* 5000 / 2;
290 EXPORT_SYMBOL(drm_dp_dual_mode_max_tmds_clock
);
293 * drm_dp_dual_mode_get_tmds_output - Get the state of the TMDS output buffers in the DP dual mode adaptor
294 * @type: DP dual mode adaptor type
295 * @adapter: I2C adapter for the DDC bus
296 * @enabled: current state of the TMDS output buffers
298 * Get the state of the TMDS output buffers in the adaptor. For
299 * type2 adaptors this is queried from the DP_DUAL_MODE_TMDS_OEN
300 * register. As some type 1 adaptors have problems with registers
301 * (see comments in drm_dp_dual_mode_detect()) we don't read the
302 * register on those, instead we simply assume that the buffers
303 * are always enabled.
306 * 0 on success, negative error code on failure
308 int drm_dp_dual_mode_get_tmds_output(enum drm_dp_dual_mode_type type
,
309 struct i2c_adapter
*adapter
,
315 if (type
< DRM_DP_DUAL_MODE_TYPE2_DVI
) {
320 ret
= drm_dp_dual_mode_read(adapter
, DP_DUAL_MODE_TMDS_OEN
,
321 &tmds_oen
, sizeof(tmds_oen
));
323 DRM_DEBUG_KMS("Failed to query state of TMDS output buffers\n");
327 *enabled
= !(tmds_oen
& DP_DUAL_MODE_TMDS_DISABLE
);
331 EXPORT_SYMBOL(drm_dp_dual_mode_get_tmds_output
);
334 * drm_dp_dual_mode_set_tmds_output - Enable/disable TMDS output buffers in the DP dual mode adaptor
335 * @type: DP dual mode adaptor type
336 * @adapter: I2C adapter for the DDC bus
337 * @enable: enable (as opposed to disable) the TMDS output buffers
339 * Set the state of the TMDS output buffers in the adaptor. For
340 * type2 this is set via the DP_DUAL_MODE_TMDS_OEN register. As
341 * some type 1 adaptors have problems with registers (see comments
342 * in drm_dp_dual_mode_detect()) we avoid touching the register,
343 * making this function a no-op on type 1 adaptors.
346 * 0 on success, negative error code on failure
348 int drm_dp_dual_mode_set_tmds_output(enum drm_dp_dual_mode_type type
,
349 struct i2c_adapter
*adapter
, bool enable
)
351 uint8_t tmds_oen
= enable
? 0 : DP_DUAL_MODE_TMDS_DISABLE
;
354 if (type
< DRM_DP_DUAL_MODE_TYPE2_DVI
)
357 ret
= drm_dp_dual_mode_write(adapter
, DP_DUAL_MODE_TMDS_OEN
,
358 &tmds_oen
, sizeof(tmds_oen
));
360 DRM_DEBUG_KMS("Failed to %s TMDS output buffers\n",
361 enable
? "enable" : "disable");
367 EXPORT_SYMBOL(drm_dp_dual_mode_set_tmds_output
);
370 * drm_dp_get_dual_mode_type_name - Get the name of the DP dual mode adaptor type as a string
371 * @type: DP dual mode adaptor type
374 * String representation of the DP dual mode adaptor type
376 const char *drm_dp_get_dual_mode_type_name(enum drm_dp_dual_mode_type type
)
379 case DRM_DP_DUAL_MODE_NONE
:
381 case DRM_DP_DUAL_MODE_TYPE1_DVI
:
383 case DRM_DP_DUAL_MODE_TYPE1_HDMI
:
384 return "type 1 HDMI";
385 case DRM_DP_DUAL_MODE_TYPE2_DVI
:
387 case DRM_DP_DUAL_MODE_TYPE2_HDMI
:
388 return "type 2 HDMI";
389 case DRM_DP_DUAL_MODE_LSPCON
:
392 WARN_ON(type
!= DRM_DP_DUAL_MODE_UNKNOWN
);
396 EXPORT_SYMBOL(drm_dp_get_dual_mode_type_name
);
399 * drm_lspcon_get_mode: Get LSPCON's current mode of operation by
400 * reading offset (0x80, 0x41)
401 * @adapter: I2C-over-aux adapter
402 * @mode: current lspcon mode of operation output variable
405 * 0 on success, sets the current_mode value to appropriate mode
408 int drm_lspcon_get_mode(struct i2c_adapter
*adapter
,
409 enum drm_lspcon_mode
*mode
)
416 DRM_ERROR("NULL input\n");
420 /* Read Status: i2c over aux */
421 for (retry
= 0; retry
< 6; retry
++) {
423 usleep_range(500, 1000);
425 ret
= drm_dp_dual_mode_read(adapter
,
426 DP_DUAL_MODE_LSPCON_CURRENT_MODE
,
427 &data
, sizeof(data
));
433 DRM_DEBUG_KMS("LSPCON read(0x80, 0x41) failed\n");
437 if (data
& DP_DUAL_MODE_LSPCON_MODE_PCON
)
438 *mode
= DRM_LSPCON_MODE_PCON
;
440 *mode
= DRM_LSPCON_MODE_LS
;
443 EXPORT_SYMBOL(drm_lspcon_get_mode
);
446 * drm_lspcon_set_mode: Change LSPCON's mode of operation by
447 * writing offset (0x80, 0x40)
448 * @adapter: I2C-over-aux adapter
449 * @mode: required mode of operation
452 * 0 on success, -error on failure/timeout
454 int drm_lspcon_set_mode(struct i2c_adapter
*adapter
,
455 enum drm_lspcon_mode mode
)
460 enum drm_lspcon_mode current_mode
;
462 if (mode
== DRM_LSPCON_MODE_PCON
)
463 data
= DP_DUAL_MODE_LSPCON_MODE_PCON
;
466 ret
= drm_dp_dual_mode_write(adapter
, DP_DUAL_MODE_LSPCON_MODE_CHANGE
,
467 &data
, sizeof(data
));
469 DRM_ERROR("LSPCON mode change failed\n");
474 * Confirm mode change by reading the status bit.
475 * Sometimes, it takes a while to change the mode,
476 * so wait and retry until time out or done.
479 ret
= drm_lspcon_get_mode(adapter
, ¤t_mode
);
481 DRM_ERROR("can't confirm LSPCON mode change\n");
484 if (current_mode
!= mode
) {
488 DRM_DEBUG_KMS("LSPCON mode changed to %s\n",
489 mode
== DRM_LSPCON_MODE_LS
?
496 DRM_ERROR("LSPCON mode change timed out\n");
499 EXPORT_SYMBOL(drm_lspcon_set_mode
);