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};
 65
 66static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;
 67
 68static u8 *stdp2690_get_edid(struct i2c_client *client)
 69{
 70	struct i2c_adapter *adapter = client->adapter;
 71	unsigned char start = 0x00;
 72	unsigned int total_size;
 73	u8 *block = kmalloc(EDID_LENGTH, GFP_KERNEL);
 74
 75	struct i2c_msg msgs[] = {
 76		{
 77			.addr	= client->addr,
 78			.flags	= 0,
 79			.len	= 1,
 80			.buf	= &start,
 81		}, {
 82			.addr	= client->addr,
 83			.flags	= I2C_M_RD,
 84			.len	= EDID_LENGTH,
 85			.buf	= block,
 86		}
 87	};
 88
 89	if (!block)
 90		return NULL;
 91
 92	if (i2c_transfer(adapter, msgs, 2) != 2) {
 93		DRM_ERROR("Unable to read EDID.\n");
 94		goto err;
 95	}
 96
 97	if (!drm_edid_block_valid(block, 0, false, NULL)) {
 98		DRM_ERROR("Invalid EDID data\n");
 99		goto err;
100	}
101
102	total_size = (block[EDID_EXT_BLOCK_CNT] + 1) * EDID_LENGTH;
103	if (total_size > EDID_LENGTH) {
104		kfree(block);
105		block = kmalloc(total_size, GFP_KERNEL);
106		if (!block)
107			return NULL;
108
109		/* Yes, read the entire buffer, and do not skip the first
110		 * EDID_LENGTH bytes.
111		 */
112		start = 0x00;
113		msgs[1].len = total_size;
114		msgs[1].buf = block;
115
116		if (i2c_transfer(adapter, msgs, 2) != 2) {
117			DRM_ERROR("Unable to read EDID extension blocks.\n");
118			goto err;
119		}
120		if (!drm_edid_block_valid(block, 1, false, NULL)) {
121			DRM_ERROR("Invalid EDID data\n");
122			goto err;
123		}
124	}
125
126	return block;
127
128err:
129	kfree(block);
130	return NULL;
131}
132
133static struct edid *ge_b850v3_lvds_get_edid(struct drm_bridge *bridge,
134					    struct drm_connector *connector)
135{
136	struct i2c_client *client;
137
138	client = ge_b850v3_lvds_ptr->stdp2690_i2c;
139
140	return (struct edid *)stdp2690_get_edid(client);
141}
142
143static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
144{
145	struct edid *edid;
146	int num_modes;
147
148	edid = ge_b850v3_lvds_get_edid(&ge_b850v3_lvds_ptr->bridge, connector);
149
150	drm_connector_update_edid_property(connector, edid);
151	num_modes = drm_add_edid_modes(connector, edid);
152	kfree(edid);
153
154	return num_modes;
155}
156
157static enum drm_mode_status ge_b850v3_lvds_mode_valid(
158		struct drm_connector *connector, struct drm_display_mode *mode)
159{
160	return MODE_OK;
161}
162
163static const struct
164drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = {
165	.get_modes = ge_b850v3_lvds_get_modes,
166	.mode_valid = ge_b850v3_lvds_mode_valid,
167};
168
169static enum drm_connector_status ge_b850v3_lvds_bridge_detect(struct drm_bridge *bridge)
170{
171	struct i2c_client *stdp4028_i2c =
172			ge_b850v3_lvds_ptr->stdp4028_i2c;
173	s32 link_state;
174
175	link_state = i2c_smbus_read_word_data(stdp4028_i2c,
176					      STDP4028_DPTX_STS_REG);
177
178	if (link_state == STDP4028_CON_STATE_CONNECTED)
179		return connector_status_connected;
180
181	if (link_state == 0)
182		return connector_status_disconnected;
183
184	return connector_status_unknown;
185}
186
187static enum drm_connector_status ge_b850v3_lvds_detect(struct drm_connector *connector,
188						       bool force)
189{
190	return ge_b850v3_lvds_bridge_detect(&ge_b850v3_lvds_ptr->bridge);
191}
192
193static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = {
194	.fill_modes = drm_helper_probe_single_connector_modes,
195	.detect = ge_b850v3_lvds_detect,
196	.destroy = drm_connector_cleanup,
197	.reset = drm_atomic_helper_connector_reset,
198	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
199	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
200};
201
202static int ge_b850v3_lvds_create_connector(struct drm_bridge *bridge)
203{
204	struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector;
205	int ret;
206
207	if (!bridge->encoder) {
208		DRM_ERROR("Parent encoder object not found");
209		return -ENODEV;
210	}
211
212	connector->polled = DRM_CONNECTOR_POLL_HPD;
213
214	drm_connector_helper_add(connector,
215				 &ge_b850v3_lvds_connector_helper_funcs);
216
217	ret = drm_connector_init(bridge->dev, connector,
218				 &ge_b850v3_lvds_connector_funcs,
219				 DRM_MODE_CONNECTOR_DisplayPort);
220	if (ret) {
221		DRM_ERROR("Failed to initialize connector with drm\n");
222		return ret;
223	}
224
225	return drm_connector_attach_encoder(connector, bridge->encoder);
226}
227
228static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id)
229{
230	struct i2c_client *stdp4028_i2c
231			= ge_b850v3_lvds_ptr->stdp4028_i2c;
232
233	i2c_smbus_write_word_data(stdp4028_i2c,
234				  STDP4028_DPTX_IRQ_STS_REG,
235				  STDP4028_DPTX_IRQ_CLEAR);
236
237	if (ge_b850v3_lvds_ptr->bridge.dev)
238		drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->bridge.dev);
239
240	return IRQ_HANDLED;
241}
242
243static int ge_b850v3_lvds_attach(struct drm_bridge *bridge,
244				 enum drm_bridge_attach_flags flags)
245{
246	struct i2c_client *stdp4028_i2c
247			= ge_b850v3_lvds_ptr->stdp4028_i2c;
248
249	/* Configures the bridge to re-enable interrupts after each ack. */
250	i2c_smbus_write_word_data(stdp4028_i2c,
251				  STDP4028_IRQ_OUT_CONF_REG,
252				  STDP4028_DPTX_DP_IRQ_EN);
253
254	/* Enable interrupts */
255	i2c_smbus_write_word_data(stdp4028_i2c,
256				  STDP4028_DPTX_IRQ_EN_REG,
257				  STDP4028_DPTX_IRQ_CONFIG);
258
259	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
260		return 0;
261
262	return ge_b850v3_lvds_create_connector(bridge);
263}
264
265static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
266	.attach = ge_b850v3_lvds_attach,
267	.detect = ge_b850v3_lvds_bridge_detect,
268	.get_edid = ge_b850v3_lvds_get_edid,
269};
270
271static int ge_b850v3_lvds_init(struct device *dev)
272{
273	mutex_lock(&ge_b850v3_lvds_dev_mutex);
274
275	if (ge_b850v3_lvds_ptr)
276		goto success;
277
278	ge_b850v3_lvds_ptr = devm_kzalloc(dev,
279					  sizeof(*ge_b850v3_lvds_ptr),
280					  GFP_KERNEL);
281
282	if (!ge_b850v3_lvds_ptr) {
283		mutex_unlock(&ge_b850v3_lvds_dev_mutex);
284		return -ENOMEM;
285	}
286
287success:
288	mutex_unlock(&ge_b850v3_lvds_dev_mutex);
289	return 0;
290}
291
292static void ge_b850v3_lvds_remove(void)
293{
294	mutex_lock(&ge_b850v3_lvds_dev_mutex);
295	/*
296	 * This check is to avoid both the drivers
297	 * removing the bridge in their remove() function
298	 */
299	if (!ge_b850v3_lvds_ptr ||
300	    !ge_b850v3_lvds_ptr->stdp2690_i2c ||
301		!ge_b850v3_lvds_ptr->stdp4028_i2c)
302		goto out;
303
304	drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
305
306	ge_b850v3_lvds_ptr = NULL;
307out:
308	mutex_unlock(&ge_b850v3_lvds_dev_mutex);
309}
310
311static int ge_b850v3_register(void)
312{
313	struct i2c_client *stdp4028_i2c = ge_b850v3_lvds_ptr->stdp4028_i2c;
314	struct device *dev = &stdp4028_i2c->dev;
315
316	/* drm bridge initialization */
317	ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs;
318	ge_b850v3_lvds_ptr->bridge.ops = DRM_BRIDGE_OP_DETECT |
319					 DRM_BRIDGE_OP_EDID;
320	ge_b850v3_lvds_ptr->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
321	ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;
322	drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);
323
324	/* Clear pending interrupts since power up. */
325	i2c_smbus_write_word_data(stdp4028_i2c,
326				  STDP4028_DPTX_IRQ_STS_REG,
327				  STDP4028_DPTX_IRQ_CLEAR);
328
329	if (!stdp4028_i2c->irq)
330		return 0;
331
332	return devm_request_threaded_irq(&stdp4028_i2c->dev,
333			stdp4028_i2c->irq, NULL,
334			ge_b850v3_lvds_irq_handler,
335			IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
336			"ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
337}
338
339static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c,
340				       const struct i2c_device_id *id)
341{
342	struct device *dev = &stdp4028_i2c->dev;
343	int ret;
344
345	ret = ge_b850v3_lvds_init(dev);
346
347	if (ret)
348		return ret;
349
350	ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;
351	i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);
352
353	/* Only register after both bridges are probed */
354	if (!ge_b850v3_lvds_ptr->stdp2690_i2c)
355		return 0;
356
357	return ge_b850v3_register();
358}
359
360static void stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
361{
362	ge_b850v3_lvds_remove();
363}
364
365static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
366	{"stdp4028_ge_fw", 0},
367	{},
368};
369MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
370
371static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
372	{ .compatible = "megachips,stdp4028-ge-b850v3-fw" },
373	{},
374};
375MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
376
377static struct i2c_driver stdp4028_ge_b850v3_fw_driver = {
378	.id_table	= stdp4028_ge_b850v3_fw_i2c_table,
379	.probe		= stdp4028_ge_b850v3_fw_probe,
380	.remove		= stdp4028_ge_b850v3_fw_remove,
381	.driver		= {
382		.name		= "stdp4028-ge-b850v3-fw",
383		.of_match_table = stdp4028_ge_b850v3_fw_match,
384	},
385};
386
387static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c,
388				       const struct i2c_device_id *id)
389{
390	struct device *dev = &stdp2690_i2c->dev;
391	int ret;
392
393	ret = ge_b850v3_lvds_init(dev);
394
395	if (ret)
396		return ret;
397
398	ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;
399	i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);
400
401	/* Only register after both bridges are probed */
402	if (!ge_b850v3_lvds_ptr->stdp4028_i2c)
403		return 0;
404
405	return ge_b850v3_register();
406}
407
408static void stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
409{
410	ge_b850v3_lvds_remove();
411}
412
413static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
414	{"stdp2690_ge_fw", 0},
415	{},
416};
417MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
418
419static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
420	{ .compatible = "megachips,stdp2690-ge-b850v3-fw" },
421	{},
422};
423MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
424
425static struct i2c_driver stdp2690_ge_b850v3_fw_driver = {
426	.id_table	= stdp2690_ge_b850v3_fw_i2c_table,
427	.probe		= stdp2690_ge_b850v3_fw_probe,
428	.remove		= stdp2690_ge_b850v3_fw_remove,
429	.driver		= {
430		.name		= "stdp2690-ge-b850v3-fw",
431		.of_match_table = stdp2690_ge_b850v3_fw_match,
432	},
433};
434
435static int __init stdpxxxx_ge_b850v3_init(void)
436{
437	int ret;
438
439	ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver);
440	if (ret)
441		return ret;
442
443	return i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
444}
445module_init(stdpxxxx_ge_b850v3_init);
446
447static void __exit stdpxxxx_ge_b850v3_exit(void)
448{
449	i2c_del_driver(&stdp2690_ge_b850v3_fw_driver);
450	i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
451}
452module_exit(stdpxxxx_ge_b850v3_exit);
453
454MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>");
455MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>");
456MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
457MODULE_LICENSE("GPL v2");