megachips-stdpxxxx-ge-b850v3-fw.c

  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 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
 94static 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
104static 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
118static const struct
119drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = {
120	.get_modes = ge_b850v3_lvds_get_modes,
121};
122
123static enum drm_connector_status
124ge_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
142static 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
148static 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
157static 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
178static 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
193static 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
216static 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
222static 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
236success:
237	mutex_unlock(&ge_b850v3_lvds_dev_mutex);
238	return 0;
239}
240
241static 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;
256out:
257	mutex_unlock(&ge_b850v3_lvds_dev_mutex);
258}
259
260static 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
287static 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
307static void stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
308{
309	ge_b850v3_lvds_remove();
310}
311
312static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
313	{ "stdp4028_ge_fw" },
314	{}
315};
316MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
317
318static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
319	{ .compatible = "megachips,stdp4028-ge-b850v3-fw" },
320	{},
321};
322MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
323
324static 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
334static 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
354static void stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
355{
356	ge_b850v3_lvds_remove();
357}
358
359static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
360	{ "stdp2690_ge_fw" },
361	{}
362};
363MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
364
365static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
366	{ .compatible = "megachips,stdp2690-ge-b850v3-fw" },
367	{},
368};
369MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
370
371static 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
381static 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}
395module_init(stdpxxxx_ge_b850v3_init);
396
397static 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}
402module_exit(stdpxxxx_ge_b850v3_exit);
403
404MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>");
405MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>");
406MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
407MODULE_LICENSE("GPL v2");