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
123 static enum drm_connector_status
ge_b850v3_lvds_bridge_detect(struct drm_bridge * bridge,struct drm_connector * connector)124 ge_b850v3_lvds_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector)
125 {
126 struct i2c_client *stdp4028_i2c =
127 ge_b850v3_lvds_ptr->stdp4028_i2c;
128 s32 link_state;
129
130 link_state = i2c_smbus_read_word_data(stdp4028_i2c,
131 STDP4028_DPTX_STS_REG);
132
133 if (link_state == STDP4028_CON_STATE_CONNECTED)
134 return connector_status_connected;
135
136 if (link_state == 0)
137 return connector_status_disconnected;
138
139 return connector_status_unknown;
140 }
141
ge_b850v3_lvds_detect(struct drm_connector * connector,bool force)142 static enum drm_connector_status ge_b850v3_lvds_detect(struct drm_connector *connector,
143 bool force)
144 {
145 return ge_b850v3_lvds_bridge_detect(&ge_b850v3_lvds_ptr->bridge, connector);
146 }
147
148 static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = {
149 .fill_modes = drm_helper_probe_single_connector_modes,
150 .detect = ge_b850v3_lvds_detect,
151 .destroy = drm_connector_cleanup,
152 .reset = drm_atomic_helper_connector_reset,
153 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
154 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
155 };
156
ge_b850v3_lvds_create_connector(struct drm_bridge * bridge)157 static int ge_b850v3_lvds_create_connector(struct drm_bridge *bridge)
158 {
159 struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector;
160 int ret;
161
162 connector->polled = DRM_CONNECTOR_POLL_HPD;
163
164 drm_connector_helper_add(connector,
165 &ge_b850v3_lvds_connector_helper_funcs);
166
167 ret = drm_connector_init(bridge->dev, connector,
168 &ge_b850v3_lvds_connector_funcs,
169 DRM_MODE_CONNECTOR_DisplayPort);
170 if (ret) {
171 DRM_ERROR("Failed to initialize connector with drm\n");
172 return ret;
173 }
174
175 return drm_connector_attach_encoder(connector, bridge->encoder);
176 }
177
ge_b850v3_lvds_irq_handler(int irq,void * dev_id)178 static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id)
179 {
180 struct i2c_client *stdp4028_i2c
181 = ge_b850v3_lvds_ptr->stdp4028_i2c;
182
183 i2c_smbus_write_word_data(stdp4028_i2c,
184 STDP4028_DPTX_IRQ_STS_REG,
185 STDP4028_DPTX_IRQ_CLEAR);
186
187 if (ge_b850v3_lvds_ptr->bridge.dev)
188 drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->bridge.dev);
189
190 return IRQ_HANDLED;
191 }
192
ge_b850v3_lvds_attach(struct drm_bridge * bridge,struct drm_encoder * encoder,enum drm_bridge_attach_flags flags)193 static int ge_b850v3_lvds_attach(struct drm_bridge *bridge,
194 struct drm_encoder *encoder,
195 enum drm_bridge_attach_flags flags)
196 {
197 struct i2c_client *stdp4028_i2c
198 = ge_b850v3_lvds_ptr->stdp4028_i2c;
199
200 /* Configures the bridge to re-enable interrupts after each ack. */
201 i2c_smbus_write_word_data(stdp4028_i2c,
202 STDP4028_IRQ_OUT_CONF_REG,
203 STDP4028_DPTX_DP_IRQ_EN);
204
205 /* Enable interrupts */
206 i2c_smbus_write_word_data(stdp4028_i2c,
207 STDP4028_DPTX_IRQ_EN_REG,
208 STDP4028_DPTX_IRQ_CONFIG);
209
210 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
211 return 0;
212
213 return ge_b850v3_lvds_create_connector(bridge);
214 }
215
216 static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
217 .attach = ge_b850v3_lvds_attach,
218 .detect = ge_b850v3_lvds_bridge_detect,
219 .edid_read = ge_b850v3_lvds_edid_read,
220 };
221
ge_b850v3_lvds_init(struct device * dev)222 static int ge_b850v3_lvds_init(struct device *dev)
223 {
224 mutex_lock(&ge_b850v3_lvds_dev_mutex);
225
226 if (ge_b850v3_lvds_ptr)
227 goto success;
228
229 ge_b850v3_lvds_ptr = devm_drm_bridge_alloc(dev, struct ge_b850v3_lvds, bridge,
230 &ge_b850v3_lvds_funcs);
231 if (IS_ERR(ge_b850v3_lvds_ptr)) {
232 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
233 return PTR_ERR(ge_b850v3_lvds_ptr);
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.ops = DRM_BRIDGE_OP_DETECT |
267 DRM_BRIDGE_OP_EDID;
268 ge_b850v3_lvds_ptr->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
269 ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;
270 drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);
271
272 /* Clear pending interrupts since power up. */
273 i2c_smbus_write_word_data(stdp4028_i2c,
274 STDP4028_DPTX_IRQ_STS_REG,
275 STDP4028_DPTX_IRQ_CLEAR);
276
277 if (!stdp4028_i2c->irq)
278 return 0;
279
280 return devm_request_threaded_irq(&stdp4028_i2c->dev,
281 stdp4028_i2c->irq, NULL,
282 ge_b850v3_lvds_irq_handler,
283 IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
284 "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
285 }
286
stdp4028_ge_b850v3_fw_probe(struct i2c_client * stdp4028_i2c)287 static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c)
288 {
289 struct device *dev = &stdp4028_i2c->dev;
290 int ret;
291
292 ret = ge_b850v3_lvds_init(dev);
293
294 if (ret)
295 return ret;
296
297 ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;
298 i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);
299
300 /* Only register after both bridges are probed */
301 if (!ge_b850v3_lvds_ptr->stdp2690_i2c)
302 return 0;
303
304 return ge_b850v3_register();
305 }
306
stdp4028_ge_b850v3_fw_remove(struct i2c_client * stdp4028_i2c)307 static void stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
308 {
309 ge_b850v3_lvds_remove();
310 }
311
312 static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
313 { "stdp4028_ge_fw" },
314 {}
315 };
316 MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
317
318 static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
319 { .compatible = "megachips,stdp4028-ge-b850v3-fw" },
320 {},
321 };
322 MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
323
324 static struct i2c_driver stdp4028_ge_b850v3_fw_driver = {
325 .id_table = stdp4028_ge_b850v3_fw_i2c_table,
326 .probe = stdp4028_ge_b850v3_fw_probe,
327 .remove = stdp4028_ge_b850v3_fw_remove,
328 .driver = {
329 .name = "stdp4028-ge-b850v3-fw",
330 .of_match_table = stdp4028_ge_b850v3_fw_match,
331 },
332 };
333
stdp2690_ge_b850v3_fw_probe(struct i2c_client * stdp2690_i2c)334 static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c)
335 {
336 struct device *dev = &stdp2690_i2c->dev;
337 int ret;
338
339 ret = ge_b850v3_lvds_init(dev);
340
341 if (ret)
342 return ret;
343
344 ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;
345 i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);
346
347 /* Only register after both bridges are probed */
348 if (!ge_b850v3_lvds_ptr->stdp4028_i2c)
349 return 0;
350
351 return ge_b850v3_register();
352 }
353
stdp2690_ge_b850v3_fw_remove(struct i2c_client * stdp2690_i2c)354 static void stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
355 {
356 ge_b850v3_lvds_remove();
357 }
358
359 static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
360 { "stdp2690_ge_fw" },
361 {}
362 };
363 MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
364
365 static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
366 { .compatible = "megachips,stdp2690-ge-b850v3-fw" },
367 {},
368 };
369 MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
370
371 static struct i2c_driver stdp2690_ge_b850v3_fw_driver = {
372 .id_table = stdp2690_ge_b850v3_fw_i2c_table,
373 .probe = stdp2690_ge_b850v3_fw_probe,
374 .remove = stdp2690_ge_b850v3_fw_remove,
375 .driver = {
376 .name = "stdp2690-ge-b850v3-fw",
377 .of_match_table = stdp2690_ge_b850v3_fw_match,
378 },
379 };
380
stdpxxxx_ge_b850v3_init(void)381 static int __init stdpxxxx_ge_b850v3_init(void)
382 {
383 int ret;
384
385 ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver);
386 if (ret)
387 return ret;
388
389 ret = i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
390 if (ret)
391 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
392
393 return ret;
394 }
395 module_init(stdpxxxx_ge_b850v3_init);
396
stdpxxxx_ge_b850v3_exit(void)397 static void __exit stdpxxxx_ge_b850v3_exit(void)
398 {
399 i2c_del_driver(&stdp2690_ge_b850v3_fw_driver);
400 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
401 }
402 module_exit(stdpxxxx_ge_b850v3_exit);
403
404 MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>");
405 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>");
406 MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
407 MODULE_LICENSE("GPL v2");
408