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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
57static DEFINE_MUTEX(ge_b850v3_lvds_dev_mutex);
58
59struct 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 struct edid *edid;
65};
66
67static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;
68
69static u8 *stdp2690_get_edid(struct i2c_client *client)
70{
71 struct i2c_adapter *adapter = client->adapter;
72 unsigned char start = 0x00;
73 unsigned int total_size;
74 u8 *block = kmalloc(EDID_LENGTH, GFP_KERNEL);
75
76 struct i2c_msg msgs[] = {
77 {
78 .addr = client->addr,
79 .flags = 0,
80 .len = 1,
81 .buf = &start,
82 }, {
83 .addr = client->addr,
84 .flags = I2C_M_RD,
85 .len = EDID_LENGTH,
86 .buf = block,
87 }
88 };
89
90 if (!block)
91 return NULL;
92
93 if (i2c_transfer(adapter, msgs, 2) != 2) {
94 DRM_ERROR("Unable to read EDID.\n");
95 goto err;
96 }
97
98 if (!drm_edid_block_valid(block, 0, false, NULL)) {
99 DRM_ERROR("Invalid EDID data\n");
100 goto err;
101 }
102
103 total_size = (block[EDID_EXT_BLOCK_CNT] + 1) * EDID_LENGTH;
104 if (total_size > EDID_LENGTH) {
105 kfree(block);
106 block = kmalloc(total_size, GFP_KERNEL);
107 if (!block)
108 return NULL;
109
110 /* Yes, read the entire buffer, and do not skip the first
111 * EDID_LENGTH bytes.
112 */
113 start = 0x00;
114 msgs[1].len = total_size;
115 msgs[1].buf = block;
116
117 if (i2c_transfer(adapter, msgs, 2) != 2) {
118 DRM_ERROR("Unable to read EDID extension blocks.\n");
119 goto err;
120 }
121 if (!drm_edid_block_valid(block, 1, false, NULL)) {
122 DRM_ERROR("Invalid EDID data\n");
123 goto err;
124 }
125 }
126
127 return block;
128
129err:
130 kfree(block);
131 return NULL;
132}
133
134static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
135{
136 struct i2c_client *client;
137 int num_modes = 0;
138
139 client = ge_b850v3_lvds_ptr->stdp2690_i2c;
140
141 kfree(ge_b850v3_lvds_ptr->edid);
142 ge_b850v3_lvds_ptr->edid = (struct edid *)stdp2690_get_edid(client);
143
144 if (ge_b850v3_lvds_ptr->edid) {
145 drm_connector_update_edid_property(connector,
146 ge_b850v3_lvds_ptr->edid);
147 num_modes = drm_add_edid_modes(connector,
148 ge_b850v3_lvds_ptr->edid);
149 }
150
151 return num_modes;
152}
153
154static enum drm_mode_status ge_b850v3_lvds_mode_valid(
155 struct drm_connector *connector, struct drm_display_mode *mode)
156{
157 return MODE_OK;
158}
159
160static const struct
161drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = {
162 .get_modes = ge_b850v3_lvds_get_modes,
163 .mode_valid = ge_b850v3_lvds_mode_valid,
164};
165
166static enum drm_connector_status ge_b850v3_lvds_detect(
167 struct drm_connector *connector, bool force)
168{
169 struct i2c_client *stdp4028_i2c =
170 ge_b850v3_lvds_ptr->stdp4028_i2c;
171 s32 link_state;
172
173 link_state = i2c_smbus_read_word_data(stdp4028_i2c,
174 STDP4028_DPTX_STS_REG);
175
176 if (link_state == STDP4028_CON_STATE_CONNECTED)
177 return connector_status_connected;
178
179 if (link_state == 0)
180 return connector_status_disconnected;
181
182 return connector_status_unknown;
183}
184
185static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = {
186 .fill_modes = drm_helper_probe_single_connector_modes,
187 .detect = ge_b850v3_lvds_detect,
188 .destroy = drm_connector_cleanup,
189 .reset = drm_atomic_helper_connector_reset,
190 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
191 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
192};
193
194static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id)
195{
196 struct i2c_client *stdp4028_i2c
197 = ge_b850v3_lvds_ptr->stdp4028_i2c;
198
199 i2c_smbus_write_word_data(stdp4028_i2c,
200 STDP4028_DPTX_IRQ_STS_REG,
201 STDP4028_DPTX_IRQ_CLEAR);
202
203 if (ge_b850v3_lvds_ptr->connector.dev)
204 drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->connector.dev);
205
206 return IRQ_HANDLED;
207}
208
209static int ge_b850v3_lvds_attach(struct drm_bridge *bridge)
210{
211 struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector;
212 struct i2c_client *stdp4028_i2c
213 = ge_b850v3_lvds_ptr->stdp4028_i2c;
214 int ret;
215
216 if (!bridge->encoder) {
217 DRM_ERROR("Parent encoder object not found");
218 return -ENODEV;
219 }
220
221 connector->polled = DRM_CONNECTOR_POLL_HPD;
222
223 drm_connector_helper_add(connector,
224 &ge_b850v3_lvds_connector_helper_funcs);
225
226 ret = drm_connector_init(bridge->dev, connector,
227 &ge_b850v3_lvds_connector_funcs,
228 DRM_MODE_CONNECTOR_DisplayPort);
229 if (ret) {
230 DRM_ERROR("Failed to initialize connector with drm\n");
231 return ret;
232 }
233
234 ret = drm_connector_attach_encoder(connector, bridge->encoder);
235 if (ret)
236 return ret;
237
238 /* Configures the bridge to re-enable interrupts after each ack. */
239 i2c_smbus_write_word_data(stdp4028_i2c,
240 STDP4028_IRQ_OUT_CONF_REG,
241 STDP4028_DPTX_DP_IRQ_EN);
242
243 /* Enable interrupts */
244 i2c_smbus_write_word_data(stdp4028_i2c,
245 STDP4028_DPTX_IRQ_EN_REG,
246 STDP4028_DPTX_IRQ_CONFIG);
247
248 return 0;
249}
250
251static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
252 .attach = ge_b850v3_lvds_attach,
253};
254
255static int ge_b850v3_lvds_init(struct device *dev)
256{
257 mutex_lock(&ge_b850v3_lvds_dev_mutex);
258
259 if (ge_b850v3_lvds_ptr)
260 goto success;
261
262 ge_b850v3_lvds_ptr = devm_kzalloc(dev,
263 sizeof(*ge_b850v3_lvds_ptr),
264 GFP_KERNEL);
265
266 if (!ge_b850v3_lvds_ptr) {
267 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
268 return -ENOMEM;
269 }
270
271success:
272 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
273 return 0;
274}
275
276static void ge_b850v3_lvds_remove(void)
277{
278 mutex_lock(&ge_b850v3_lvds_dev_mutex);
279 /*
280 * This check is to avoid both the drivers
281 * removing the bridge in their remove() function
282 */
283 if (!ge_b850v3_lvds_ptr)
284 goto out;
285
286 drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
287
288 kfree(ge_b850v3_lvds_ptr->edid);
289
290 ge_b850v3_lvds_ptr = NULL;
291out:
292 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
293}
294
295static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c,
296 const struct i2c_device_id *id)
297{
298 struct device *dev = &stdp4028_i2c->dev;
299
300 ge_b850v3_lvds_init(dev);
301
302 ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;
303 i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);
304
305 /* drm bridge initialization */
306 ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs;
307 ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;
308 drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);
309
310 /* Clear pending interrupts since power up. */
311 i2c_smbus_write_word_data(stdp4028_i2c,
312 STDP4028_DPTX_IRQ_STS_REG,
313 STDP4028_DPTX_IRQ_CLEAR);
314
315 if (!stdp4028_i2c->irq)
316 return 0;
317
318 return devm_request_threaded_irq(&stdp4028_i2c->dev,
319 stdp4028_i2c->irq, NULL,
320 ge_b850v3_lvds_irq_handler,
321 IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
322 "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
323}
324
325static int stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
326{
327 ge_b850v3_lvds_remove();
328
329 return 0;
330}
331
332static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
333 {"stdp4028_ge_fw", 0},
334 {},
335};
336MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
337
338static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
339 { .compatible = "megachips,stdp4028-ge-b850v3-fw" },
340 {},
341};
342MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
343
344static struct i2c_driver stdp4028_ge_b850v3_fw_driver = {
345 .id_table = stdp4028_ge_b850v3_fw_i2c_table,
346 .probe = stdp4028_ge_b850v3_fw_probe,
347 .remove = stdp4028_ge_b850v3_fw_remove,
348 .driver = {
349 .name = "stdp4028-ge-b850v3-fw",
350 .of_match_table = stdp4028_ge_b850v3_fw_match,
351 },
352};
353
354static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c,
355 const struct i2c_device_id *id)
356{
357 struct device *dev = &stdp2690_i2c->dev;
358
359 ge_b850v3_lvds_init(dev);
360
361 ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;
362 i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);
363
364 return 0;
365}
366
367static int stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
368{
369 ge_b850v3_lvds_remove();
370
371 return 0;
372}
373
374static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
375 {"stdp2690_ge_fw", 0},
376 {},
377};
378MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
379
380static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
381 { .compatible = "megachips,stdp2690-ge-b850v3-fw" },
382 {},
383};
384MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
385
386static struct i2c_driver stdp2690_ge_b850v3_fw_driver = {
387 .id_table = stdp2690_ge_b850v3_fw_i2c_table,
388 .probe = stdp2690_ge_b850v3_fw_probe,
389 .remove = stdp2690_ge_b850v3_fw_remove,
390 .driver = {
391 .name = "stdp2690-ge-b850v3-fw",
392 .of_match_table = stdp2690_ge_b850v3_fw_match,
393 },
394};
395
396static int __init stdpxxxx_ge_b850v3_init(void)
397{
398 int ret;
399
400 ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver);
401 if (ret)
402 return ret;
403
404 return i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
405}
406module_init(stdpxxxx_ge_b850v3_init);
407
408static void __exit stdpxxxx_ge_b850v3_exit(void)
409{
410 i2c_del_driver(&stdp2690_ge_b850v3_fw_driver);
411 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
412}
413module_exit(stdpxxxx_ge_b850v3_exit);
414
415MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>");
416MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>");
417MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
418MODULE_LICENSE("GPL v2");