1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for MegaChips STDP4028 with GE B850v3 firmware (LVDS-DP)
4 * Driver for MegaChips STDP2690 with GE B850v3 firmware (DP-DP++)
5
6 * Copyright (c) 2017, Collabora Ltd.
7 * Copyright (c) 2017, General Electric Company
8
9
10 * This driver creates a drm_bridge and a drm_connector for the LVDS to DP++
11 * display bridge of the GE B850v3. There are two physical bridges on the video
12 * signal pipeline: a STDP4028(LVDS to DP) and a STDP2690(DP to DP++). The
13 * physical bridges are automatically configured by the input video signal, and
14 * the driver has no access to the video processing pipeline. The driver is
15 * only needed to read EDID from the STDP2690 and to handle HPD events from the
16 * STDP4028. The driver communicates with both bridges over i2c. The video
17 * signal pipeline is as follows:
18 *
19 * Host -> LVDS|--(STDP4028)--|DP -> DP|--(STDP2690)--|DP++ -> Video output
20 */
21
22 #include <linux/i2c.h>
23 #include <linux/module.h>
24 #include <linux/of.h>
25
26 #include <drm/drm_atomic.h>
27 #include <drm/drm_atomic_helper.h>
28 #include <drm/drm_bridge.h>
29 #include <drm/drm_edid.h>
30 #include <drm/drm_print.h>
31 #include <drm/drm_probe_helper.h>
32
33 #define EDID_EXT_BLOCK_CNT 0x7E
34
35 #define STDP4028_IRQ_OUT_CONF_REG 0x02
36 #define STDP4028_DPTX_IRQ_EN_REG 0x3C
37 #define STDP4028_DPTX_IRQ_STS_REG 0x3D
38 #define STDP4028_DPTX_STS_REG 0x3E
39
40 #define STDP4028_DPTX_DP_IRQ_EN 0x1000
41
42 #define STDP4028_DPTX_HOTPLUG_IRQ_EN 0x0400
43 #define STDP4028_DPTX_LINK_CH_IRQ_EN 0x2000
44 #define STDP4028_DPTX_IRQ_CONFIG \
45 (STDP4028_DPTX_LINK_CH_IRQ_EN | STDP4028_DPTX_HOTPLUG_IRQ_EN)
46
47 #define STDP4028_DPTX_HOTPLUG_STS 0x0200
48 #define STDP4028_DPTX_LINK_STS 0x1000
49 #define STDP4028_CON_STATE_CONNECTED \
50 (STDP4028_DPTX_HOTPLUG_STS | STDP4028_DPTX_LINK_STS)
51
52 #define STDP4028_DPTX_HOTPLUG_CH_STS 0x0400
53 #define STDP4028_DPTX_LINK_CH_STS 0x2000
54 #define STDP4028_DPTX_IRQ_CLEAR \
55 (STDP4028_DPTX_LINK_CH_STS | STDP4028_DPTX_HOTPLUG_CH_STS)
56
57 static DEFINE_MUTEX(ge_b850v3_lvds_dev_mutex);
58
59 struct ge_b850v3_lvds {
60 struct drm_connector connector;
61 struct drm_bridge bridge;
62 struct i2c_client *stdp4028_i2c;
63 struct i2c_client *stdp2690_i2c;
64 };
65
66 static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;
67
stdp2690_read_block(void * context,u8 * buf,unsigned int block,size_t len)68 static int stdp2690_read_block(void *context, u8 *buf, unsigned int block, size_t len)
69 {
70 struct i2c_client *client = context;
71 struct i2c_adapter *adapter = client->adapter;
72 unsigned char start = block * EDID_LENGTH;
73
74 struct i2c_msg msgs[] = {
75 {
76 .addr = client->addr,
77 .flags = 0,
78 .len = 1,
79 .buf = &start,
80 }, {
81 .addr = client->addr,
82 .flags = I2C_M_RD,
83 .len = len,
84 .buf = buf,
85 }
86 };
87
88 if (i2c_transfer(adapter, msgs, 2) != 2)
89 return -1;
90
91 return 0;
92 }
93
ge_b850v3_lvds_edid_read(struct drm_bridge * bridge,struct drm_connector * connector)94 static const struct drm_edid *ge_b850v3_lvds_edid_read(struct drm_bridge *bridge,
95 struct drm_connector *connector)
96 {
97 struct i2c_client *client;
98
99 client = ge_b850v3_lvds_ptr->stdp2690_i2c;
100
101 return drm_edid_read_custom(connector, stdp2690_read_block, client);
102 }
103
ge_b850v3_lvds_get_modes(struct drm_connector * connector)104 static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
105 {
106 const struct drm_edid *drm_edid;
107 int num_modes;
108
109 drm_edid = ge_b850v3_lvds_edid_read(&ge_b850v3_lvds_ptr->bridge, connector);
110
111 drm_edid_connector_update(connector, drm_edid);
112 num_modes = drm_edid_connector_add_modes(connector);
113 drm_edid_free(drm_edid);
114
115 return num_modes;
116 }
117
118 static const struct
119 drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = {
120 .get_modes = ge_b850v3_lvds_get_modes,
121 };
122
ge_b850v3_lvds_bridge_detect(struct drm_bridge * bridge)123 static enum drm_connector_status ge_b850v3_lvds_bridge_detect(struct drm_bridge *bridge)
124 {
125 struct i2c_client *stdp4028_i2c =
126 ge_b850v3_lvds_ptr->stdp4028_i2c;
127 s32 link_state;
128
129 link_state = i2c_smbus_read_word_data(stdp4028_i2c,
130 STDP4028_DPTX_STS_REG);
131
132 if (link_state == STDP4028_CON_STATE_CONNECTED)
133 return connector_status_connected;
134
135 if (link_state == 0)
136 return connector_status_disconnected;
137
138 return connector_status_unknown;
139 }
140
ge_b850v3_lvds_detect(struct drm_connector * connector,bool force)141 static enum drm_connector_status ge_b850v3_lvds_detect(struct drm_connector *connector,
142 bool force)
143 {
144 return ge_b850v3_lvds_bridge_detect(&ge_b850v3_lvds_ptr->bridge);
145 }
146
147 static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = {
148 .fill_modes = drm_helper_probe_single_connector_modes,
149 .detect = ge_b850v3_lvds_detect,
150 .destroy = drm_connector_cleanup,
151 .reset = drm_atomic_helper_connector_reset,
152 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
153 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
154 };
155
ge_b850v3_lvds_create_connector(struct drm_bridge * bridge)156 static int ge_b850v3_lvds_create_connector(struct drm_bridge *bridge)
157 {
158 struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector;
159 int ret;
160
161 connector->polled = DRM_CONNECTOR_POLL_HPD;
162
163 drm_connector_helper_add(connector,
164 &ge_b850v3_lvds_connector_helper_funcs);
165
166 ret = drm_connector_init(bridge->dev, connector,
167 &ge_b850v3_lvds_connector_funcs,
168 DRM_MODE_CONNECTOR_DisplayPort);
169 if (ret) {
170 DRM_ERROR("Failed to initialize connector with drm\n");
171 return ret;
172 }
173
174 return drm_connector_attach_encoder(connector, bridge->encoder);
175 }
176
ge_b850v3_lvds_irq_handler(int irq,void * dev_id)177 static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id)
178 {
179 struct i2c_client *stdp4028_i2c
180 = ge_b850v3_lvds_ptr->stdp4028_i2c;
181
182 i2c_smbus_write_word_data(stdp4028_i2c,
183 STDP4028_DPTX_IRQ_STS_REG,
184 STDP4028_DPTX_IRQ_CLEAR);
185
186 if (ge_b850v3_lvds_ptr->bridge.dev)
187 drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->bridge.dev);
188
189 return IRQ_HANDLED;
190 }
191
ge_b850v3_lvds_attach(struct drm_bridge * bridge,enum drm_bridge_attach_flags flags)192 static int ge_b850v3_lvds_attach(struct drm_bridge *bridge,
193 enum drm_bridge_attach_flags flags)
194 {
195 struct i2c_client *stdp4028_i2c
196 = ge_b850v3_lvds_ptr->stdp4028_i2c;
197
198 /* Configures the bridge to re-enable interrupts after each ack. */
199 i2c_smbus_write_word_data(stdp4028_i2c,
200 STDP4028_IRQ_OUT_CONF_REG,
201 STDP4028_DPTX_DP_IRQ_EN);
202
203 /* Enable interrupts */
204 i2c_smbus_write_word_data(stdp4028_i2c,
205 STDP4028_DPTX_IRQ_EN_REG,
206 STDP4028_DPTX_IRQ_CONFIG);
207
208 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
209 return 0;
210
211 return ge_b850v3_lvds_create_connector(bridge);
212 }
213
214 static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
215 .attach = ge_b850v3_lvds_attach,
216 .detect = ge_b850v3_lvds_bridge_detect,
217 .edid_read = ge_b850v3_lvds_edid_read,
218 };
219
ge_b850v3_lvds_init(struct device * dev)220 static int ge_b850v3_lvds_init(struct device *dev)
221 {
222 mutex_lock(&ge_b850v3_lvds_dev_mutex);
223
224 if (ge_b850v3_lvds_ptr)
225 goto success;
226
227 ge_b850v3_lvds_ptr = devm_kzalloc(dev,
228 sizeof(*ge_b850v3_lvds_ptr),
229 GFP_KERNEL);
230
231 if (!ge_b850v3_lvds_ptr) {
232 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
233 return -ENOMEM;
234 }
235
236 success:
237 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
238 return 0;
239 }
240
ge_b850v3_lvds_remove(void)241 static void ge_b850v3_lvds_remove(void)
242 {
243 mutex_lock(&ge_b850v3_lvds_dev_mutex);
244 /*
245 * This check is to avoid both the drivers
246 * removing the bridge in their remove() function
247 */
248 if (!ge_b850v3_lvds_ptr ||
249 !ge_b850v3_lvds_ptr->stdp2690_i2c ||
250 !ge_b850v3_lvds_ptr->stdp4028_i2c)
251 goto out;
252
253 drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
254
255 ge_b850v3_lvds_ptr = NULL;
256 out:
257 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
258 }
259
ge_b850v3_register(void)260 static int ge_b850v3_register(void)
261 {
262 struct i2c_client *stdp4028_i2c = ge_b850v3_lvds_ptr->stdp4028_i2c;
263 struct device *dev = &stdp4028_i2c->dev;
264
265 /* drm bridge initialization */
266 ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs;
267 ge_b850v3_lvds_ptr->bridge.ops = DRM_BRIDGE_OP_DETECT |
268 DRM_BRIDGE_OP_EDID;
269 ge_b850v3_lvds_ptr->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
270 ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;
271 drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);
272
273 /* Clear pending interrupts since power up. */
274 i2c_smbus_write_word_data(stdp4028_i2c,
275 STDP4028_DPTX_IRQ_STS_REG,
276 STDP4028_DPTX_IRQ_CLEAR);
277
278 if (!stdp4028_i2c->irq)
279 return 0;
280
281 return devm_request_threaded_irq(&stdp4028_i2c->dev,
282 stdp4028_i2c->irq, NULL,
283 ge_b850v3_lvds_irq_handler,
284 IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
285 "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
286 }
287
stdp4028_ge_b850v3_fw_probe(struct i2c_client * stdp4028_i2c)288 static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c)
289 {
290 struct device *dev = &stdp4028_i2c->dev;
291 int ret;
292
293 ret = ge_b850v3_lvds_init(dev);
294
295 if (ret)
296 return ret;
297
298 ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;
299 i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);
300
301 /* Only register after both bridges are probed */
302 if (!ge_b850v3_lvds_ptr->stdp2690_i2c)
303 return 0;
304
305 return ge_b850v3_register();
306 }
307
stdp4028_ge_b850v3_fw_remove(struct i2c_client * stdp4028_i2c)308 static void stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
309 {
310 ge_b850v3_lvds_remove();
311 }
312
313 static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
314 { "stdp4028_ge_fw" },
315 {}
316 };
317 MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
318
319 static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
320 { .compatible = "megachips,stdp4028-ge-b850v3-fw" },
321 {},
322 };
323 MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
324
325 static struct i2c_driver stdp4028_ge_b850v3_fw_driver = {
326 .id_table = stdp4028_ge_b850v3_fw_i2c_table,
327 .probe = stdp4028_ge_b850v3_fw_probe,
328 .remove = stdp4028_ge_b850v3_fw_remove,
329 .driver = {
330 .name = "stdp4028-ge-b850v3-fw",
331 .of_match_table = stdp4028_ge_b850v3_fw_match,
332 },
333 };
334
stdp2690_ge_b850v3_fw_probe(struct i2c_client * stdp2690_i2c)335 static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c)
336 {
337 struct device *dev = &stdp2690_i2c->dev;
338 int ret;
339
340 ret = ge_b850v3_lvds_init(dev);
341
342 if (ret)
343 return ret;
344
345 ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;
346 i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);
347
348 /* Only register after both bridges are probed */
349 if (!ge_b850v3_lvds_ptr->stdp4028_i2c)
350 return 0;
351
352 return ge_b850v3_register();
353 }
354
stdp2690_ge_b850v3_fw_remove(struct i2c_client * stdp2690_i2c)355 static void stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
356 {
357 ge_b850v3_lvds_remove();
358 }
359
360 static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
361 { "stdp2690_ge_fw" },
362 {}
363 };
364 MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
365
366 static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
367 { .compatible = "megachips,stdp2690-ge-b850v3-fw" },
368 {},
369 };
370 MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
371
372 static struct i2c_driver stdp2690_ge_b850v3_fw_driver = {
373 .id_table = stdp2690_ge_b850v3_fw_i2c_table,
374 .probe = stdp2690_ge_b850v3_fw_probe,
375 .remove = stdp2690_ge_b850v3_fw_remove,
376 .driver = {
377 .name = "stdp2690-ge-b850v3-fw",
378 .of_match_table = stdp2690_ge_b850v3_fw_match,
379 },
380 };
381
stdpxxxx_ge_b850v3_init(void)382 static int __init stdpxxxx_ge_b850v3_init(void)
383 {
384 int ret;
385
386 ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver);
387 if (ret)
388 return ret;
389
390 ret = i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
391 if (ret)
392 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
393
394 return ret;
395 }
396 module_init(stdpxxxx_ge_b850v3_init);
397
stdpxxxx_ge_b850v3_exit(void)398 static void __exit stdpxxxx_ge_b850v3_exit(void)
399 {
400 i2c_del_driver(&stdp2690_ge_b850v3_fw_driver);
401 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
402 }
403 module_exit(stdpxxxx_ge_b850v3_exit);
404
405 MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>");
406 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>");
407 MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
408 MODULE_LICENSE("GPL v2");
409