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ede53344 VS |
1 | /* |
2 | * Copyright © 2016 Intel Corporation | |
3 | * | |
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: | |
10 | * | |
11 | * The above copyright notice and this permission notice shall be included in | |
12 | * all copies or substantial portions of the Software. | |
13 | * | |
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. | |
21 | */ | |
22 | ||
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> | |
29 | #include <drm/drmP.h> | |
30 | ||
31 | /** | |
32 | * DOC: dp dual mode helpers | |
33 | * | |
34 | * Helper functions to deal with DP dual mode (aka. DP++) adaptors. | |
35 | * | |
36 | * Type 1: | |
37 | * Adaptor registers (if any) and the sink DDC bus may be accessed via I2C. | |
38 | * | |
39 | * Type 2: | |
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 | |
42 | * access methods. | |
43 | */ | |
44 | ||
45 | #define DP_DUAL_MODE_SLAVE_ADDRESS 0x40 | |
46 | ||
47 | /** | |
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 | |
53 | * | |
54 | * Reads @size bytes from the DP dual mode adaptor registers | |
55 | * starting at @offset. | |
56 | * | |
57 | * Returns: | |
58 | * 0 on success, negative error code on failure | |
59 | */ | |
60 | ssize_t drm_dp_dual_mode_read(struct i2c_adapter *adapter, | |
61 | u8 offset, void *buffer, size_t size) | |
62 | { | |
63 | struct i2c_msg msgs[] = { | |
64 | { | |
65 | .addr = DP_DUAL_MODE_SLAVE_ADDRESS, | |
66 | .flags = 0, | |
67 | .len = 1, | |
68 | .buf = &offset, | |
69 | }, | |
70 | { | |
71 | .addr = DP_DUAL_MODE_SLAVE_ADDRESS, | |
72 | .flags = I2C_M_RD, | |
73 | .len = size, | |
74 | .buf = buffer, | |
75 | }, | |
76 | }; | |
77 | int ret; | |
78 | ||
79 | ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs)); | |
80 | if (ret < 0) | |
81 | return ret; | |
82 | if (ret != ARRAY_SIZE(msgs)) | |
83 | return -EPROTO; | |
84 | ||
85 | return 0; | |
86 | } | |
87 | EXPORT_SYMBOL(drm_dp_dual_mode_read); | |
88 | ||
89 | /** | |
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 | |
95 | * | |
96 | * Writes @size bytes to the DP dual mode adaptor registers | |
97 | * starting at @offset. | |
98 | * | |
99 | * Returns: | |
100 | * 0 on success, negative error code on failure | |
101 | */ | |
102 | ssize_t drm_dp_dual_mode_write(struct i2c_adapter *adapter, | |
103 | u8 offset, const void *buffer, size_t size) | |
104 | { | |
105 | struct i2c_msg msg = { | |
106 | .addr = DP_DUAL_MODE_SLAVE_ADDRESS, | |
107 | .flags = 0, | |
108 | .len = 1 + size, | |
109 | .buf = NULL, | |
110 | }; | |
111 | void *data; | |
112 | int ret; | |
113 | ||
114 | data = kmalloc(msg.len, GFP_TEMPORARY); | |
115 | if (!data) | |
116 | return -ENOMEM; | |
117 | ||
118 | msg.buf = data; | |
119 | ||
120 | memcpy(data, &offset, 1); | |
121 | memcpy(data + 1, buffer, size); | |
122 | ||
123 | ret = i2c_transfer(adapter, &msg, 1); | |
124 | ||
125 | kfree(data); | |
126 | ||
127 | if (ret < 0) | |
128 | return ret; | |
129 | if (ret != 1) | |
130 | return -EPROTO; | |
131 | ||
132 | return 0; | |
133 | } | |
134 | EXPORT_SYMBOL(drm_dp_dual_mode_write); | |
135 | ||
136 | static bool is_hdmi_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN]) | |
137 | { | |
138 | static const char dp_dual_mode_hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN] = | |
139 | "DP-HDMI ADAPTOR\x04"; | |
140 | ||
141 | return memcmp(hdmi_id, dp_dual_mode_hdmi_id, | |
142 | sizeof(dp_dual_mode_hdmi_id)) == 0; | |
143 | } | |
144 | ||
145 | static bool is_type2_adaptor(uint8_t adaptor_id) | |
146 | { | |
147 | return adaptor_id == (DP_DUAL_MODE_TYPE_TYPE2 | | |
148 | DP_DUAL_MODE_REV_TYPE2); | |
149 | } | |
150 | ||
151 | /** | |
152 | * drm_dp_dual_mode_detect - Identify the DP dual mode adaptor | |
153 | * @adapter: I2C adapter for the DDC bus | |
154 | * | |
155 | * Attempt to identify the type of the DP dual mode adaptor used. | |
156 | * | |
157 | * Note that when the answer is @DRM_DP_DUAL_MODE_UNKNOWN it's not | |
158 | * certain whether we're dealing with a native HDMI port or | |
159 | * a type 1 DVI dual mode adaptor. The driver will have to use | |
160 | * some other hardware/driver specific mechanism to make that | |
161 | * distinction. | |
162 | * | |
163 | * Returns: | |
164 | * The type of the DP dual mode adaptor used | |
165 | */ | |
166 | enum drm_dp_dual_mode_type drm_dp_dual_mode_detect(struct i2c_adapter *adapter) | |
167 | { | |
168 | char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN] = {}; | |
169 | uint8_t adaptor_id = 0x00; | |
170 | ssize_t ret; | |
171 | ||
172 | /* | |
173 | * Let's see if the adaptor is there the by reading the | |
174 | * HDMI ID registers. | |
175 | * | |
176 | * Note that type 1 DVI adaptors are not required to implemnt | |
177 | * any registers, and that presents a problem for detection. | |
178 | * If the i2c transfer is nacked, we may or may not be dealing | |
179 | * with a type 1 DVI adaptor. Some other mechanism of detecting | |
180 | * the presence of the adaptor is required. One way would be | |
181 | * to check the state of the CONFIG1 pin, Another method would | |
182 | * simply require the driver to know whether the port is a DP++ | |
183 | * port or a native HDMI port. Both of these methods are entirely | |
184 | * hardware/driver specific so we can't deal with them here. | |
185 | */ | |
186 | ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_HDMI_ID, | |
187 | hdmi_id, sizeof(hdmi_id)); | |
188 | if (ret) | |
189 | return DRM_DP_DUAL_MODE_UNKNOWN; | |
190 | ||
191 | /* | |
192 | * Sigh. Some (maybe all?) type 1 adaptors are broken and ack | |
193 | * the offset but ignore it, and instead they just always return | |
194 | * data from the start of the HDMI ID buffer. So for a broken | |
195 | * type 1 HDMI adaptor a single byte read will always give us | |
196 | * 0x44, and for a type 1 DVI adaptor it should give 0x00 | |
197 | * (assuming it implements any registers). Fortunately neither | |
198 | * of those values will match the type 2 signature of the | |
199 | * DP_DUAL_MODE_ADAPTOR_ID register so we can proceed with | |
200 | * the type 2 adaptor detection safely even in the presence | |
201 | * of broken type 1 adaptors. | |
202 | */ | |
203 | ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_ADAPTOR_ID, | |
204 | &adaptor_id, sizeof(adaptor_id)); | |
205 | if (ret == 0) { | |
206 | if (is_type2_adaptor(adaptor_id)) { | |
207 | if (is_hdmi_adaptor(hdmi_id)) | |
208 | return DRM_DP_DUAL_MODE_TYPE2_HDMI; | |
209 | else | |
210 | return DRM_DP_DUAL_MODE_TYPE2_DVI; | |
211 | } | |
212 | } | |
213 | ||
214 | if (is_hdmi_adaptor(hdmi_id)) | |
215 | return DRM_DP_DUAL_MODE_TYPE1_HDMI; | |
216 | else | |
217 | return DRM_DP_DUAL_MODE_TYPE1_DVI; | |
218 | } | |
219 | EXPORT_SYMBOL(drm_dp_dual_mode_detect); | |
220 | ||
221 | /** | |
222 | * drm_dp_dual_mode_max_tmds_clock - Max TMDS clock for DP dual mode adaptor | |
223 | * @type: DP dual mode adaptor type | |
224 | * @adapter: I2C adapter for the DDC bus | |
225 | * | |
226 | * Determine the max TMDS clock the adaptor supports based on the | |
227 | * type of the dual mode adaptor and the DP_DUAL_MODE_MAX_TMDS_CLOCK | |
228 | * register (on type2 adaptors). As some type 1 adaptors have | |
229 | * problems with registers (see comments in drm_dp_dual_mode_detect()) | |
230 | * we don't read the register on those, instead we simply assume | |
231 | * a 165 MHz limit based on the specification. | |
232 | * | |
233 | * Returns: | |
234 | * Maximum supported TMDS clock rate for the DP dual mode adaptor in kHz. | |
235 | */ | |
236 | int drm_dp_dual_mode_max_tmds_clock(enum drm_dp_dual_mode_type type, | |
237 | struct i2c_adapter *adapter) | |
238 | { | |
239 | uint8_t max_tmds_clock; | |
240 | ssize_t ret; | |
241 | ||
242 | /* native HDMI so no limit */ | |
243 | if (type == DRM_DP_DUAL_MODE_NONE) | |
244 | return 0; | |
245 | ||
246 | /* | |
247 | * Type 1 adaptors are limited to 165MHz | |
248 | * Type 2 adaptors can tells us their limit | |
249 | */ | |
250 | if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) | |
251 | return 165000; | |
252 | ||
253 | ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_MAX_TMDS_CLOCK, | |
254 | &max_tmds_clock, sizeof(max_tmds_clock)); | |
255 | if (ret || max_tmds_clock == 0x00 || max_tmds_clock == 0xff) { | |
256 | DRM_DEBUG_KMS("Failed to query max TMDS clock\n"); | |
257 | return 165000; | |
258 | } | |
259 | ||
260 | return max_tmds_clock * 5000 / 2; | |
261 | } | |
262 | EXPORT_SYMBOL(drm_dp_dual_mode_max_tmds_clock); | |
263 | ||
264 | /** | |
265 | * drm_dp_dual_mode_get_tmds_output - Get the state of the TMDS output buffers in the DP dual mode adaptor | |
266 | * @type: DP dual mode adaptor type | |
267 | * @adapter: I2C adapter for the DDC bus | |
268 | * @enabled: current state of the TMDS output buffers | |
269 | * | |
270 | * Get the state of the TMDS output buffers in the adaptor. For | |
271 | * type2 adaptors this is queried from the DP_DUAL_MODE_TMDS_OEN | |
272 | * register. As some type 1 adaptors have problems with registers | |
273 | * (see comments in drm_dp_dual_mode_detect()) we don't read the | |
274 | * register on those, instead we simply assume that the buffers | |
275 | * are always enabled. | |
276 | * | |
277 | * Returns: | |
278 | * 0 on success, negative error code on failure | |
279 | */ | |
280 | int drm_dp_dual_mode_get_tmds_output(enum drm_dp_dual_mode_type type, | |
281 | struct i2c_adapter *adapter, | |
282 | bool *enabled) | |
283 | { | |
284 | uint8_t tmds_oen; | |
285 | ssize_t ret; | |
286 | ||
287 | if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) { | |
288 | *enabled = true; | |
289 | return 0; | |
290 | } | |
291 | ||
292 | ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_TMDS_OEN, | |
293 | &tmds_oen, sizeof(tmds_oen)); | |
294 | if (ret) { | |
295 | DRM_DEBUG_KMS("Failed to query state of TMDS output buffers\n"); | |
296 | return ret; | |
297 | } | |
298 | ||
299 | *enabled = !(tmds_oen & DP_DUAL_MODE_TMDS_DISABLE); | |
300 | ||
301 | return 0; | |
302 | } | |
303 | EXPORT_SYMBOL(drm_dp_dual_mode_get_tmds_output); | |
304 | ||
305 | /** | |
306 | * drm_dp_dual_mode_set_tmds_output - Enable/disable TMDS output buffers in the DP dual mode adaptor | |
307 | * @type: DP dual mode adaptor type | |
308 | * @adapter: I2C adapter for the DDC bus | |
309 | * @enable: enable (as opposed to disable) the TMDS output buffers | |
310 | * | |
311 | * Set the state of the TMDS output buffers in the adaptor. For | |
312 | * type2 this is set via the DP_DUAL_MODE_TMDS_OEN register. As | |
313 | * some type 1 adaptors have problems with registers (see comments | |
314 | * in drm_dp_dual_mode_detect()) we avoid touching the register, | |
315 | * making this function a no-op on type 1 adaptors. | |
316 | * | |
317 | * Returns: | |
318 | * 0 on success, negative error code on failure | |
319 | */ | |
320 | int drm_dp_dual_mode_set_tmds_output(enum drm_dp_dual_mode_type type, | |
321 | struct i2c_adapter *adapter, bool enable) | |
322 | { | |
323 | uint8_t tmds_oen = enable ? 0 : DP_DUAL_MODE_TMDS_DISABLE; | |
324 | ssize_t ret; | |
325 | ||
326 | if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) | |
327 | return 0; | |
328 | ||
329 | ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_TMDS_OEN, | |
330 | &tmds_oen, sizeof(tmds_oen)); | |
331 | if (ret) { | |
332 | DRM_DEBUG_KMS("Failed to %s TMDS output buffers\n", | |
333 | enable ? "enable" : "disable"); | |
334 | return ret; | |
335 | } | |
336 | ||
337 | return 0; | |
338 | } | |
339 | EXPORT_SYMBOL(drm_dp_dual_mode_set_tmds_output); | |
340 | ||
341 | /** | |
342 | * drm_dp_get_dual_mode_type_name - Get the name of the DP dual mode adaptor type as a string | |
343 | * @type: DP dual mode adaptor type | |
344 | * | |
345 | * Returns: | |
346 | * String representation of the DP dual mode adaptor type | |
347 | */ | |
348 | const char *drm_dp_get_dual_mode_type_name(enum drm_dp_dual_mode_type type) | |
349 | { | |
350 | switch (type) { | |
351 | case DRM_DP_DUAL_MODE_NONE: | |
352 | return "none"; | |
353 | case DRM_DP_DUAL_MODE_TYPE1_DVI: | |
354 | return "type 1 DVI"; | |
355 | case DRM_DP_DUAL_MODE_TYPE1_HDMI: | |
356 | return "type 1 HDMI"; | |
357 | case DRM_DP_DUAL_MODE_TYPE2_DVI: | |
358 | return "type 2 DVI"; | |
359 | case DRM_DP_DUAL_MODE_TYPE2_HDMI: | |
360 | return "type 2 HDMI"; | |
361 | default: | |
362 | WARN_ON(type != DRM_DP_DUAL_MODE_UNKNOWN); | |
363 | return "unknown"; | |
364 | } | |
365 | } | |
366 | EXPORT_SYMBOL(drm_dp_get_dual_mode_type_name); |