1 /*
2 * Driver for MegaChips STDP4028 with GE B850v3 firmware (LVDS-DP)
3 * Driver for MegaChips STDP2690 with GE B850v3 firmware (DP-DP++)
4
5 * Copyright (c) 2017, Collabora Ltd.
6 * Copyright (c) 2017, General Electric Company
7
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms and conditions of the GNU General Public License,
10 * version 2, as published by the Free Software Foundation.
11
12 * This program is distributed in the hope it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * more details.
16
17 * You should have received a copy of the GNU General Public License
18 * along with this program. If not, see <http://www.gnu.org/licenses/>.
19
20 * This driver creates a drm_bridge and a drm_connector for the LVDS to DP++
21 * display bridge of the GE B850v3. There are two physical bridges on the video
22 * signal pipeline: a STDP4028(LVDS to DP) and a STDP2690(DP to DP++). The
23 * physical bridges are automatically configured by the input video signal, and
24 * the driver has no access to the video processing pipeline. The driver is
25 * only needed to read EDID from the STDP2690 and to handle HPD events from the
26 * STDP4028. The driver communicates with both bridges over i2c. The video
27 * signal pipeline is as follows:
28 *
29 * Host -> LVDS|--(STDP4028)--|DP -> DP|--(STDP2690)--|DP++ -> Video output
30 *
31 */
32
33 #include <linux/gpio.h>
34 #include <linux/i2c.h>
35 #include <linux/module.h>
36 #include <linux/of.h>
37 #include <drm/drm_atomic.h>
38 #include <drm/drm_atomic_helper.h>
39 #include <drm/drm_crtc_helper.h>
40 #include <drm/drm_edid.h>
41 #include <drm/drmP.h>
42
43 #define EDID_EXT_BLOCK_CNT 0x7E
44
45 #define STDP4028_IRQ_OUT_CONF_REG 0x02
46 #define STDP4028_DPTX_IRQ_EN_REG 0x3C
47 #define STDP4028_DPTX_IRQ_STS_REG 0x3D
48 #define STDP4028_DPTX_STS_REG 0x3E
49
50 #define STDP4028_DPTX_DP_IRQ_EN 0x1000
51
52 #define STDP4028_DPTX_HOTPLUG_IRQ_EN 0x0400
53 #define STDP4028_DPTX_LINK_CH_IRQ_EN 0x2000
54 #define STDP4028_DPTX_IRQ_CONFIG \
55 (STDP4028_DPTX_LINK_CH_IRQ_EN | STDP4028_DPTX_HOTPLUG_IRQ_EN)
56
57 #define STDP4028_DPTX_HOTPLUG_STS 0x0200
58 #define STDP4028_DPTX_LINK_STS 0x1000
59 #define STDP4028_CON_STATE_CONNECTED \
60 (STDP4028_DPTX_HOTPLUG_STS | STDP4028_DPTX_LINK_STS)
61
62 #define STDP4028_DPTX_HOTPLUG_CH_STS 0x0400
63 #define STDP4028_DPTX_LINK_CH_STS 0x2000
64 #define STDP4028_DPTX_IRQ_CLEAR \
65 (STDP4028_DPTX_LINK_CH_STS | STDP4028_DPTX_HOTPLUG_CH_STS)
66
67 static DEFINE_MUTEX(ge_b850v3_lvds_dev_mutex);
68
69 struct ge_b850v3_lvds {
70 struct drm_connector connector;
71 struct drm_bridge bridge;
72 struct i2c_client *stdp4028_i2c;
73 struct i2c_client *stdp2690_i2c;
74 struct edid *edid;
75 };
76
77 static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;
78
stdp2690_get_edid(struct i2c_client * client)79 static u8 *stdp2690_get_edid(struct i2c_client *client)
80 {
81 struct i2c_adapter *adapter = client->adapter;
82 unsigned char start = 0x00;
83 unsigned int total_size;
84 u8 *block = kmalloc(EDID_LENGTH, GFP_KERNEL);
85
86 struct i2c_msg msgs[] = {
87 {
88 .addr = client->addr,
89 .flags = 0,
90 .len = 1,
91 .buf = &start,
92 }, {
93 .addr = client->addr,
94 .flags = I2C_M_RD,
95 .len = EDID_LENGTH,
96 .buf = block,
97 }
98 };
99
100 if (!block)
101 return NULL;
102
103 if (i2c_transfer(adapter, msgs, 2) != 2) {
104 DRM_ERROR("Unable to read EDID.\n");
105 goto err;
106 }
107
108 if (!drm_edid_block_valid(block, 0, false, NULL)) {
109 DRM_ERROR("Invalid EDID data\n");
110 goto err;
111 }
112
113 total_size = (block[EDID_EXT_BLOCK_CNT] + 1) * EDID_LENGTH;
114 if (total_size > EDID_LENGTH) {
115 kfree(block);
116 block = kmalloc(total_size, GFP_KERNEL);
117 if (!block)
118 return NULL;
119
120 /* Yes, read the entire buffer, and do not skip the first
121 * EDID_LENGTH bytes.
122 */
123 start = 0x00;
124 msgs[1].len = total_size;
125 msgs[1].buf = block;
126
127 if (i2c_transfer(adapter, msgs, 2) != 2) {
128 DRM_ERROR("Unable to read EDID extension blocks.\n");
129 goto err;
130 }
131 if (!drm_edid_block_valid(block, 1, false, NULL)) {
132 DRM_ERROR("Invalid EDID data\n");
133 goto err;
134 }
135 }
136
137 return block;
138
139 err:
140 kfree(block);
141 return NULL;
142 }
143
ge_b850v3_lvds_get_modes(struct drm_connector * connector)144 static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
145 {
146 struct i2c_client *client;
147 int num_modes = 0;
148
149 client = ge_b850v3_lvds_ptr->stdp2690_i2c;
150
151 kfree(ge_b850v3_lvds_ptr->edid);
152 ge_b850v3_lvds_ptr->edid = (struct edid *)stdp2690_get_edid(client);
153
154 if (ge_b850v3_lvds_ptr->edid) {
155 drm_connector_update_edid_property(connector,
156 ge_b850v3_lvds_ptr->edid);
157 num_modes = drm_add_edid_modes(connector,
158 ge_b850v3_lvds_ptr->edid);
159 }
160
161 return num_modes;
162 }
163
ge_b850v3_lvds_mode_valid(struct drm_connector * connector,struct drm_display_mode * mode)164 static enum drm_mode_status ge_b850v3_lvds_mode_valid(
165 struct drm_connector *connector, struct drm_display_mode *mode)
166 {
167 return MODE_OK;
168 }
169
170 static const struct
171 drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = {
172 .get_modes = ge_b850v3_lvds_get_modes,
173 .mode_valid = ge_b850v3_lvds_mode_valid,
174 };
175
ge_b850v3_lvds_detect(struct drm_connector * connector,bool force)176 static enum drm_connector_status ge_b850v3_lvds_detect(
177 struct drm_connector *connector, bool force)
178 {
179 struct i2c_client *stdp4028_i2c =
180 ge_b850v3_lvds_ptr->stdp4028_i2c;
181 s32 link_state;
182
183 link_state = i2c_smbus_read_word_data(stdp4028_i2c,
184 STDP4028_DPTX_STS_REG);
185
186 if (link_state == STDP4028_CON_STATE_CONNECTED)
187 return connector_status_connected;
188
189 if (link_state == 0)
190 return connector_status_disconnected;
191
192 return connector_status_unknown;
193 }
194
195 static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = {
196 .fill_modes = drm_helper_probe_single_connector_modes,
197 .detect = ge_b850v3_lvds_detect,
198 .destroy = drm_connector_cleanup,
199 .reset = drm_atomic_helper_connector_reset,
200 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
201 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
202 };
203
ge_b850v3_lvds_irq_handler(int irq,void * dev_id)204 static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id)
205 {
206 struct i2c_client *stdp4028_i2c
207 = ge_b850v3_lvds_ptr->stdp4028_i2c;
208
209 i2c_smbus_write_word_data(stdp4028_i2c,
210 STDP4028_DPTX_IRQ_STS_REG,
211 STDP4028_DPTX_IRQ_CLEAR);
212
213 if (ge_b850v3_lvds_ptr->connector.dev)
214 drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->connector.dev);
215
216 return IRQ_HANDLED;
217 }
218
ge_b850v3_lvds_attach(struct drm_bridge * bridge)219 static int ge_b850v3_lvds_attach(struct drm_bridge *bridge)
220 {
221 struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector;
222 struct i2c_client *stdp4028_i2c
223 = ge_b850v3_lvds_ptr->stdp4028_i2c;
224 int ret;
225
226 if (!bridge->encoder) {
227 DRM_ERROR("Parent encoder object not found");
228 return -ENODEV;
229 }
230
231 connector->polled = DRM_CONNECTOR_POLL_HPD;
232
233 drm_connector_helper_add(connector,
234 &ge_b850v3_lvds_connector_helper_funcs);
235
236 ret = drm_connector_init(bridge->dev, connector,
237 &ge_b850v3_lvds_connector_funcs,
238 DRM_MODE_CONNECTOR_DisplayPort);
239 if (ret) {
240 DRM_ERROR("Failed to initialize connector with drm\n");
241 return ret;
242 }
243
244 ret = drm_connector_attach_encoder(connector, bridge->encoder);
245 if (ret)
246 return ret;
247
248 /* Configures the bridge to re-enable interrupts after each ack. */
249 i2c_smbus_write_word_data(stdp4028_i2c,
250 STDP4028_IRQ_OUT_CONF_REG,
251 STDP4028_DPTX_DP_IRQ_EN);
252
253 /* Enable interrupts */
254 i2c_smbus_write_word_data(stdp4028_i2c,
255 STDP4028_DPTX_IRQ_EN_REG,
256 STDP4028_DPTX_IRQ_CONFIG);
257
258 return 0;
259 }
260
261 static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
262 .attach = ge_b850v3_lvds_attach,
263 };
264
ge_b850v3_lvds_init(struct device * dev)265 static int ge_b850v3_lvds_init(struct device *dev)
266 {
267 mutex_lock(&ge_b850v3_lvds_dev_mutex);
268
269 if (ge_b850v3_lvds_ptr)
270 goto success;
271
272 ge_b850v3_lvds_ptr = devm_kzalloc(dev,
273 sizeof(*ge_b850v3_lvds_ptr),
274 GFP_KERNEL);
275
276 if (!ge_b850v3_lvds_ptr) {
277 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
278 return -ENOMEM;
279 }
280
281 success:
282 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
283 return 0;
284 }
285
ge_b850v3_lvds_remove(void)286 static void ge_b850v3_lvds_remove(void)
287 {
288 mutex_lock(&ge_b850v3_lvds_dev_mutex);
289 /*
290 * This check is to avoid both the drivers
291 * removing the bridge in their remove() function
292 */
293 if (!ge_b850v3_lvds_ptr)
294 goto out;
295
296 drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
297
298 kfree(ge_b850v3_lvds_ptr->edid);
299
300 ge_b850v3_lvds_ptr = NULL;
301 out:
302 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
303 }
304
stdp4028_ge_b850v3_fw_probe(struct i2c_client * stdp4028_i2c,const struct i2c_device_id * id)305 static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c,
306 const struct i2c_device_id *id)
307 {
308 struct device *dev = &stdp4028_i2c->dev;
309
310 ge_b850v3_lvds_init(dev);
311
312 ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;
313 i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);
314
315 /* drm bridge initialization */
316 ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs;
317 ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;
318 drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);
319
320 /* Clear pending interrupts since power up. */
321 i2c_smbus_write_word_data(stdp4028_i2c,
322 STDP4028_DPTX_IRQ_STS_REG,
323 STDP4028_DPTX_IRQ_CLEAR);
324
325 if (!stdp4028_i2c->irq)
326 return 0;
327
328 return devm_request_threaded_irq(&stdp4028_i2c->dev,
329 stdp4028_i2c->irq, NULL,
330 ge_b850v3_lvds_irq_handler,
331 IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
332 "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
333 }
334
stdp4028_ge_b850v3_fw_remove(struct i2c_client * stdp4028_i2c)335 static int stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
336 {
337 ge_b850v3_lvds_remove();
338
339 return 0;
340 }
341
342 static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
343 {"stdp4028_ge_fw", 0},
344 {},
345 };
346 MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
347
348 static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
349 { .compatible = "megachips,stdp4028-ge-b850v3-fw" },
350 {},
351 };
352 MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
353
354 static struct i2c_driver stdp4028_ge_b850v3_fw_driver = {
355 .id_table = stdp4028_ge_b850v3_fw_i2c_table,
356 .probe = stdp4028_ge_b850v3_fw_probe,
357 .remove = stdp4028_ge_b850v3_fw_remove,
358 .driver = {
359 .name = "stdp4028-ge-b850v3-fw",
360 .of_match_table = stdp4028_ge_b850v3_fw_match,
361 },
362 };
363
stdp2690_ge_b850v3_fw_probe(struct i2c_client * stdp2690_i2c,const struct i2c_device_id * id)364 static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c,
365 const struct i2c_device_id *id)
366 {
367 struct device *dev = &stdp2690_i2c->dev;
368
369 ge_b850v3_lvds_init(dev);
370
371 ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;
372 i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);
373
374 return 0;
375 }
376
stdp2690_ge_b850v3_fw_remove(struct i2c_client * stdp2690_i2c)377 static int stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
378 {
379 ge_b850v3_lvds_remove();
380
381 return 0;
382 }
383
384 static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
385 {"stdp2690_ge_fw", 0},
386 {},
387 };
388 MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
389
390 static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
391 { .compatible = "megachips,stdp2690-ge-b850v3-fw" },
392 {},
393 };
394 MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
395
396 static struct i2c_driver stdp2690_ge_b850v3_fw_driver = {
397 .id_table = stdp2690_ge_b850v3_fw_i2c_table,
398 .probe = stdp2690_ge_b850v3_fw_probe,
399 .remove = stdp2690_ge_b850v3_fw_remove,
400 .driver = {
401 .name = "stdp2690-ge-b850v3-fw",
402 .of_match_table = stdp2690_ge_b850v3_fw_match,
403 },
404 };
405
stdpxxxx_ge_b850v3_init(void)406 static int __init stdpxxxx_ge_b850v3_init(void)
407 {
408 int ret;
409
410 ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver);
411 if (ret)
412 return ret;
413
414 return i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
415 }
416 module_init(stdpxxxx_ge_b850v3_init);
417
stdpxxxx_ge_b850v3_exit(void)418 static void __exit stdpxxxx_ge_b850v3_exit(void)
419 {
420 i2c_del_driver(&stdp2690_ge_b850v3_fw_driver);
421 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
422 }
423 module_exit(stdpxxxx_ge_b850v3_exit);
424
425 MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>");
426 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>");
427 MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
428 MODULE_LICENSE("GPL v2");
429
