xref: /linux/drivers/gpu/drm/drm_mipi_dsi.c (revision 18f90d372cf35b387663f1567de701e5393f6eb5)
1 /*
2  * MIPI DSI Bus
3  *
4  * Copyright (C) 2012-2013, Samsung Electronics, Co., Ltd.
5  * Andrzej Hajda <a.hajda@samsung.com>
6  *
7  * Permission is hereby granted, free of charge, to any person obtaining a
8  * copy of this software and associated documentation files (the
9  * "Software"), to deal in the Software without restriction, including
10  * without limitation the rights to use, copy, modify, merge, publish,
11  * distribute, sub license, and/or sell copies of the Software, and to
12  * permit persons to whom the Software is furnished to do so, subject to
13  * the following conditions:
14  *
15  * The above copyright notice and this permission notice (including the
16  * next paragraph) shall be included in all copies or substantial portions
17  * of the Software.
18  *
19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
22  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
23  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
24  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
25  * USE OR OTHER DEALINGS IN THE SOFTWARE.
26  */
27 
28 #include <drm/drm_mipi_dsi.h>
29 
30 #include <linux/device.h>
31 #include <linux/module.h>
32 #include <linux/of_device.h>
33 #include <linux/pm_runtime.h>
34 #include <linux/slab.h>
35 
36 #include <video/mipi_display.h>
37 
38 /**
39  * DOC: dsi helpers
40  *
41  * These functions contain some common logic and helpers to deal with MIPI DSI
42  * peripherals.
43  *
44  * Helpers are provided for a number of standard MIPI DSI command as well as a
45  * subset of the MIPI DCS command set.
46  */
47 
48 static int mipi_dsi_device_match(struct device *dev, struct device_driver *drv)
49 {
50 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(dev);
51 
52 	/* attempt OF style match */
53 	if (of_driver_match_device(dev, drv))
54 		return 1;
55 
56 	/* compare DSI device and driver names */
57 	if (!strcmp(dsi->name, drv->name))
58 		return 1;
59 
60 	return 0;
61 }
62 
63 static int mipi_dsi_uevent(struct device *dev, struct kobj_uevent_env *env)
64 {
65 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(dev);
66 	int err;
67 
68 	err = of_device_uevent_modalias(dev, env);
69 	if (err != -ENODEV)
70 		return err;
71 
72 	add_uevent_var(env, "MODALIAS=%s%s", MIPI_DSI_MODULE_PREFIX,
73 		       dsi->name);
74 
75 	return 0;
76 }
77 
78 static const struct dev_pm_ops mipi_dsi_device_pm_ops = {
79 	.runtime_suspend = pm_generic_runtime_suspend,
80 	.runtime_resume = pm_generic_runtime_resume,
81 	.suspend = pm_generic_suspend,
82 	.resume = pm_generic_resume,
83 	.freeze = pm_generic_freeze,
84 	.thaw = pm_generic_thaw,
85 	.poweroff = pm_generic_poweroff,
86 	.restore = pm_generic_restore,
87 };
88 
89 static struct bus_type mipi_dsi_bus_type = {
90 	.name = "mipi-dsi",
91 	.match = mipi_dsi_device_match,
92 	.uevent = mipi_dsi_uevent,
93 	.pm = &mipi_dsi_device_pm_ops,
94 };
95 
96 static int of_device_match(struct device *dev, void *data)
97 {
98 	return dev->of_node == data;
99 }
100 
101 /**
102  * of_find_mipi_dsi_device_by_node() - find the MIPI DSI device matching a
103  *    device tree node
104  * @np: device tree node
105  *
106  * Return: A pointer to the MIPI DSI device corresponding to @np or NULL if no
107  *    such device exists (or has not been registered yet).
108  */
109 struct mipi_dsi_device *of_find_mipi_dsi_device_by_node(struct device_node *np)
110 {
111 	struct device *dev;
112 
113 	dev = bus_find_device(&mipi_dsi_bus_type, NULL, np, of_device_match);
114 
115 	return dev ? to_mipi_dsi_device(dev) : NULL;
116 }
117 EXPORT_SYMBOL(of_find_mipi_dsi_device_by_node);
118 
119 static void mipi_dsi_dev_release(struct device *dev)
120 {
121 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(dev);
122 
123 	of_node_put(dev->of_node);
124 	kfree(dsi);
125 }
126 
127 static const struct device_type mipi_dsi_device_type = {
128 	.release = mipi_dsi_dev_release,
129 };
130 
131 static struct mipi_dsi_device *mipi_dsi_device_alloc(struct mipi_dsi_host *host)
132 {
133 	struct mipi_dsi_device *dsi;
134 
135 	dsi = kzalloc(sizeof(*dsi), GFP_KERNEL);
136 	if (!dsi)
137 		return ERR_PTR(-ENOMEM);
138 
139 	dsi->host = host;
140 	dsi->dev.bus = &mipi_dsi_bus_type;
141 	dsi->dev.parent = host->dev;
142 	dsi->dev.type = &mipi_dsi_device_type;
143 
144 	device_initialize(&dsi->dev);
145 
146 	return dsi;
147 }
148 
149 static int mipi_dsi_device_add(struct mipi_dsi_device *dsi)
150 {
151 	struct mipi_dsi_host *host = dsi->host;
152 
153 	dev_set_name(&dsi->dev, "%s.%d", dev_name(host->dev),  dsi->channel);
154 
155 	return device_add(&dsi->dev);
156 }
157 
158 #if IS_ENABLED(CONFIG_OF)
159 static struct mipi_dsi_device *
160 of_mipi_dsi_device_add(struct mipi_dsi_host *host, struct device_node *node)
161 {
162 	struct device *dev = host->dev;
163 	struct mipi_dsi_device_info info = { };
164 	int ret;
165 	u32 reg;
166 
167 	if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
168 		dev_err(dev, "modalias failure on %pOF\n", node);
169 		return ERR_PTR(-EINVAL);
170 	}
171 
172 	ret = of_property_read_u32(node, "reg", &reg);
173 	if (ret) {
174 		dev_err(dev, "device node %pOF has no valid reg property: %d\n",
175 			node, ret);
176 		return ERR_PTR(-EINVAL);
177 	}
178 
179 	info.channel = reg;
180 	info.node = of_node_get(node);
181 
182 	return mipi_dsi_device_register_full(host, &info);
183 }
184 #else
185 static struct mipi_dsi_device *
186 of_mipi_dsi_device_add(struct mipi_dsi_host *host, struct device_node *node)
187 {
188 	return ERR_PTR(-ENODEV);
189 }
190 #endif
191 
192 /**
193  * mipi_dsi_device_register_full - create a MIPI DSI device
194  * @host: DSI host to which this device is connected
195  * @info: pointer to template containing DSI device information
196  *
197  * Create a MIPI DSI device by using the device information provided by
198  * mipi_dsi_device_info template
199  *
200  * Returns:
201  * A pointer to the newly created MIPI DSI device, or, a pointer encoded
202  * with an error
203  */
204 struct mipi_dsi_device *
205 mipi_dsi_device_register_full(struct mipi_dsi_host *host,
206 			      const struct mipi_dsi_device_info *info)
207 {
208 	struct mipi_dsi_device *dsi;
209 	struct device *dev = host->dev;
210 	int ret;
211 
212 	if (!info) {
213 		dev_err(dev, "invalid mipi_dsi_device_info pointer\n");
214 		return ERR_PTR(-EINVAL);
215 	}
216 
217 	if (info->channel > 3) {
218 		dev_err(dev, "invalid virtual channel: %u\n", info->channel);
219 		return ERR_PTR(-EINVAL);
220 	}
221 
222 	dsi = mipi_dsi_device_alloc(host);
223 	if (IS_ERR(dsi)) {
224 		dev_err(dev, "failed to allocate DSI device %ld\n",
225 			PTR_ERR(dsi));
226 		return dsi;
227 	}
228 
229 	dsi->dev.of_node = info->node;
230 	dsi->channel = info->channel;
231 	strlcpy(dsi->name, info->type, sizeof(dsi->name));
232 
233 	ret = mipi_dsi_device_add(dsi);
234 	if (ret) {
235 		dev_err(dev, "failed to add DSI device %d\n", ret);
236 		kfree(dsi);
237 		return ERR_PTR(ret);
238 	}
239 
240 	return dsi;
241 }
242 EXPORT_SYMBOL(mipi_dsi_device_register_full);
243 
244 /**
245  * mipi_dsi_device_unregister - unregister MIPI DSI device
246  * @dsi: DSI peripheral device
247  */
248 void mipi_dsi_device_unregister(struct mipi_dsi_device *dsi)
249 {
250 	device_unregister(&dsi->dev);
251 }
252 EXPORT_SYMBOL(mipi_dsi_device_unregister);
253 
254 static DEFINE_MUTEX(host_lock);
255 static LIST_HEAD(host_list);
256 
257 /**
258  * of_find_mipi_dsi_host_by_node() - find the MIPI DSI host matching a
259  *				     device tree node
260  * @node: device tree node
261  *
262  * Returns:
263  * A pointer to the MIPI DSI host corresponding to @node or NULL if no
264  * such device exists (or has not been registered yet).
265  */
266 struct mipi_dsi_host *of_find_mipi_dsi_host_by_node(struct device_node *node)
267 {
268 	struct mipi_dsi_host *host;
269 
270 	mutex_lock(&host_lock);
271 
272 	list_for_each_entry(host, &host_list, list) {
273 		if (host->dev->of_node == node) {
274 			mutex_unlock(&host_lock);
275 			return host;
276 		}
277 	}
278 
279 	mutex_unlock(&host_lock);
280 
281 	return NULL;
282 }
283 EXPORT_SYMBOL(of_find_mipi_dsi_host_by_node);
284 
285 int mipi_dsi_host_register(struct mipi_dsi_host *host)
286 {
287 	struct device_node *node;
288 
289 	for_each_available_child_of_node(host->dev->of_node, node) {
290 		/* skip nodes without reg property */
291 		if (!of_find_property(node, "reg", NULL))
292 			continue;
293 		of_mipi_dsi_device_add(host, node);
294 	}
295 
296 	mutex_lock(&host_lock);
297 	list_add_tail(&host->list, &host_list);
298 	mutex_unlock(&host_lock);
299 
300 	return 0;
301 }
302 EXPORT_SYMBOL(mipi_dsi_host_register);
303 
304 static int mipi_dsi_remove_device_fn(struct device *dev, void *priv)
305 {
306 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(dev);
307 
308 	mipi_dsi_device_unregister(dsi);
309 
310 	return 0;
311 }
312 
313 void mipi_dsi_host_unregister(struct mipi_dsi_host *host)
314 {
315 	device_for_each_child(host->dev, NULL, mipi_dsi_remove_device_fn);
316 
317 	mutex_lock(&host_lock);
318 	list_del_init(&host->list);
319 	mutex_unlock(&host_lock);
320 }
321 EXPORT_SYMBOL(mipi_dsi_host_unregister);
322 
323 /**
324  * mipi_dsi_attach - attach a DSI device to its DSI host
325  * @dsi: DSI peripheral
326  */
327 int mipi_dsi_attach(struct mipi_dsi_device *dsi)
328 {
329 	const struct mipi_dsi_host_ops *ops = dsi->host->ops;
330 
331 	if (!ops || !ops->attach)
332 		return -ENOSYS;
333 
334 	return ops->attach(dsi->host, dsi);
335 }
336 EXPORT_SYMBOL(mipi_dsi_attach);
337 
338 /**
339  * mipi_dsi_detach - detach a DSI device from its DSI host
340  * @dsi: DSI peripheral
341  */
342 int mipi_dsi_detach(struct mipi_dsi_device *dsi)
343 {
344 	const struct mipi_dsi_host_ops *ops = dsi->host->ops;
345 
346 	if (!ops || !ops->detach)
347 		return -ENOSYS;
348 
349 	return ops->detach(dsi->host, dsi);
350 }
351 EXPORT_SYMBOL(mipi_dsi_detach);
352 
353 static ssize_t mipi_dsi_device_transfer(struct mipi_dsi_device *dsi,
354 					struct mipi_dsi_msg *msg)
355 {
356 	const struct mipi_dsi_host_ops *ops = dsi->host->ops;
357 
358 	if (!ops || !ops->transfer)
359 		return -ENOSYS;
360 
361 	if (dsi->mode_flags & MIPI_DSI_MODE_LPM)
362 		msg->flags |= MIPI_DSI_MSG_USE_LPM;
363 
364 	return ops->transfer(dsi->host, msg);
365 }
366 
367 /**
368  * mipi_dsi_packet_format_is_short - check if a packet is of the short format
369  * @type: MIPI DSI data type of the packet
370  *
371  * Return: true if the packet for the given data type is a short packet, false
372  * otherwise.
373  */
374 bool mipi_dsi_packet_format_is_short(u8 type)
375 {
376 	switch (type) {
377 	case MIPI_DSI_V_SYNC_START:
378 	case MIPI_DSI_V_SYNC_END:
379 	case MIPI_DSI_H_SYNC_START:
380 	case MIPI_DSI_H_SYNC_END:
381 	case MIPI_DSI_END_OF_TRANSMISSION:
382 	case MIPI_DSI_COLOR_MODE_OFF:
383 	case MIPI_DSI_COLOR_MODE_ON:
384 	case MIPI_DSI_SHUTDOWN_PERIPHERAL:
385 	case MIPI_DSI_TURN_ON_PERIPHERAL:
386 	case MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM:
387 	case MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM:
388 	case MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM:
389 	case MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM:
390 	case MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM:
391 	case MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM:
392 	case MIPI_DSI_DCS_SHORT_WRITE:
393 	case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
394 	case MIPI_DSI_DCS_READ:
395 	case MIPI_DSI_DCS_COMPRESSION_MODE:
396 	case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
397 		return true;
398 	}
399 
400 	return false;
401 }
402 EXPORT_SYMBOL(mipi_dsi_packet_format_is_short);
403 
404 /**
405  * mipi_dsi_packet_format_is_long - check if a packet is of the long format
406  * @type: MIPI DSI data type of the packet
407  *
408  * Return: true if the packet for the given data type is a long packet, false
409  * otherwise.
410  */
411 bool mipi_dsi_packet_format_is_long(u8 type)
412 {
413 	switch (type) {
414 	case MIPI_DSI_PPS_LONG_WRITE:
415 	case MIPI_DSI_NULL_PACKET:
416 	case MIPI_DSI_BLANKING_PACKET:
417 	case MIPI_DSI_GENERIC_LONG_WRITE:
418 	case MIPI_DSI_DCS_LONG_WRITE:
419 	case MIPI_DSI_LOOSELY_PACKED_PIXEL_STREAM_YCBCR20:
420 	case MIPI_DSI_PACKED_PIXEL_STREAM_YCBCR24:
421 	case MIPI_DSI_PACKED_PIXEL_STREAM_YCBCR16:
422 	case MIPI_DSI_PACKED_PIXEL_STREAM_30:
423 	case MIPI_DSI_PACKED_PIXEL_STREAM_36:
424 	case MIPI_DSI_PACKED_PIXEL_STREAM_YCBCR12:
425 	case MIPI_DSI_PACKED_PIXEL_STREAM_16:
426 	case MIPI_DSI_PACKED_PIXEL_STREAM_18:
427 	case MIPI_DSI_PIXEL_STREAM_3BYTE_18:
428 	case MIPI_DSI_PACKED_PIXEL_STREAM_24:
429 		return true;
430 	}
431 
432 	return false;
433 }
434 EXPORT_SYMBOL(mipi_dsi_packet_format_is_long);
435 
436 /**
437  * mipi_dsi_create_packet - create a packet from a message according to the
438  *     DSI protocol
439  * @packet: pointer to a DSI packet structure
440  * @msg: message to translate into a packet
441  *
442  * Return: 0 on success or a negative error code on failure.
443  */
444 int mipi_dsi_create_packet(struct mipi_dsi_packet *packet,
445 			   const struct mipi_dsi_msg *msg)
446 {
447 	if (!packet || !msg)
448 		return -EINVAL;
449 
450 	/* do some minimum sanity checking */
451 	if (!mipi_dsi_packet_format_is_short(msg->type) &&
452 	    !mipi_dsi_packet_format_is_long(msg->type))
453 		return -EINVAL;
454 
455 	if (msg->channel > 3)
456 		return -EINVAL;
457 
458 	memset(packet, 0, sizeof(*packet));
459 	packet->header[0] = ((msg->channel & 0x3) << 6) | (msg->type & 0x3f);
460 
461 	/* TODO: compute ECC if hardware support is not available */
462 
463 	/*
464 	 * Long write packets contain the word count in header bytes 1 and 2.
465 	 * The payload follows the header and is word count bytes long.
466 	 *
467 	 * Short write packets encode up to two parameters in header bytes 1
468 	 * and 2.
469 	 */
470 	if (mipi_dsi_packet_format_is_long(msg->type)) {
471 		packet->header[1] = (msg->tx_len >> 0) & 0xff;
472 		packet->header[2] = (msg->tx_len >> 8) & 0xff;
473 
474 		packet->payload_length = msg->tx_len;
475 		packet->payload = msg->tx_buf;
476 	} else {
477 		const u8 *tx = msg->tx_buf;
478 
479 		packet->header[1] = (msg->tx_len > 0) ? tx[0] : 0;
480 		packet->header[2] = (msg->tx_len > 1) ? tx[1] : 0;
481 	}
482 
483 	packet->size = sizeof(packet->header) + packet->payload_length;
484 
485 	return 0;
486 }
487 EXPORT_SYMBOL(mipi_dsi_create_packet);
488 
489 /**
490  * mipi_dsi_shutdown_peripheral() - sends a Shutdown Peripheral command
491  * @dsi: DSI peripheral device
492  *
493  * Return: 0 on success or a negative error code on failure.
494  */
495 int mipi_dsi_shutdown_peripheral(struct mipi_dsi_device *dsi)
496 {
497 	struct mipi_dsi_msg msg = {
498 		.channel = dsi->channel,
499 		.type = MIPI_DSI_SHUTDOWN_PERIPHERAL,
500 		.tx_buf = (u8 [2]) { 0, 0 },
501 		.tx_len = 2,
502 	};
503 	int ret = mipi_dsi_device_transfer(dsi, &msg);
504 
505 	return (ret < 0) ? ret : 0;
506 }
507 EXPORT_SYMBOL(mipi_dsi_shutdown_peripheral);
508 
509 /**
510  * mipi_dsi_turn_on_peripheral() - sends a Turn On Peripheral command
511  * @dsi: DSI peripheral device
512  *
513  * Return: 0 on success or a negative error code on failure.
514  */
515 int mipi_dsi_turn_on_peripheral(struct mipi_dsi_device *dsi)
516 {
517 	struct mipi_dsi_msg msg = {
518 		.channel = dsi->channel,
519 		.type = MIPI_DSI_TURN_ON_PERIPHERAL,
520 		.tx_buf = (u8 [2]) { 0, 0 },
521 		.tx_len = 2,
522 	};
523 	int ret = mipi_dsi_device_transfer(dsi, &msg);
524 
525 	return (ret < 0) ? ret : 0;
526 }
527 EXPORT_SYMBOL(mipi_dsi_turn_on_peripheral);
528 
529 /*
530  * mipi_dsi_set_maximum_return_packet_size() - specify the maximum size of the
531  *    the payload in a long packet transmitted from the peripheral back to the
532  *    host processor
533  * @dsi: DSI peripheral device
534  * @value: the maximum size of the payload
535  *
536  * Return: 0 on success or a negative error code on failure.
537  */
538 int mipi_dsi_set_maximum_return_packet_size(struct mipi_dsi_device *dsi,
539 					    u16 value)
540 {
541 	u8 tx[2] = { value & 0xff, value >> 8 };
542 	struct mipi_dsi_msg msg = {
543 		.channel = dsi->channel,
544 		.type = MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE,
545 		.tx_len = sizeof(tx),
546 		.tx_buf = tx,
547 	};
548 	int ret = mipi_dsi_device_transfer(dsi, &msg);
549 
550 	return (ret < 0) ? ret : 0;
551 }
552 EXPORT_SYMBOL(mipi_dsi_set_maximum_return_packet_size);
553 
554 /**
555  * mipi_dsi_generic_write() - transmit data using a generic write packet
556  * @dsi: DSI peripheral device
557  * @payload: buffer containing the payload
558  * @size: size of payload buffer
559  *
560  * This function will automatically choose the right data type depending on
561  * the payload length.
562  *
563  * Return: The number of bytes transmitted on success or a negative error code
564  * on failure.
565  */
566 ssize_t mipi_dsi_generic_write(struct mipi_dsi_device *dsi, const void *payload,
567 			       size_t size)
568 {
569 	struct mipi_dsi_msg msg = {
570 		.channel = dsi->channel,
571 		.tx_buf = payload,
572 		.tx_len = size
573 	};
574 
575 	switch (size) {
576 	case 0:
577 		msg.type = MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM;
578 		break;
579 
580 	case 1:
581 		msg.type = MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM;
582 		break;
583 
584 	case 2:
585 		msg.type = MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM;
586 		break;
587 
588 	default:
589 		msg.type = MIPI_DSI_GENERIC_LONG_WRITE;
590 		break;
591 	}
592 
593 	return mipi_dsi_device_transfer(dsi, &msg);
594 }
595 EXPORT_SYMBOL(mipi_dsi_generic_write);
596 
597 /**
598  * mipi_dsi_generic_read() - receive data using a generic read packet
599  * @dsi: DSI peripheral device
600  * @params: buffer containing the request parameters
601  * @num_params: number of request parameters
602  * @data: buffer in which to return the received data
603  * @size: size of receive buffer
604  *
605  * This function will automatically choose the right data type depending on
606  * the number of parameters passed in.
607  *
608  * Return: The number of bytes successfully read or a negative error code on
609  * failure.
610  */
611 ssize_t mipi_dsi_generic_read(struct mipi_dsi_device *dsi, const void *params,
612 			      size_t num_params, void *data, size_t size)
613 {
614 	struct mipi_dsi_msg msg = {
615 		.channel = dsi->channel,
616 		.tx_len = num_params,
617 		.tx_buf = params,
618 		.rx_len = size,
619 		.rx_buf = data
620 	};
621 
622 	switch (num_params) {
623 	case 0:
624 		msg.type = MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM;
625 		break;
626 
627 	case 1:
628 		msg.type = MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM;
629 		break;
630 
631 	case 2:
632 		msg.type = MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM;
633 		break;
634 
635 	default:
636 		return -EINVAL;
637 	}
638 
639 	return mipi_dsi_device_transfer(dsi, &msg);
640 }
641 EXPORT_SYMBOL(mipi_dsi_generic_read);
642 
643 /**
644  * mipi_dsi_dcs_write_buffer() - transmit a DCS command with payload
645  * @dsi: DSI peripheral device
646  * @data: buffer containing data to be transmitted
647  * @len: size of transmission buffer
648  *
649  * This function will automatically choose the right data type depending on
650  * the command payload length.
651  *
652  * Return: The number of bytes successfully transmitted or a negative error
653  * code on failure.
654  */
655 ssize_t mipi_dsi_dcs_write_buffer(struct mipi_dsi_device *dsi,
656 				  const void *data, size_t len)
657 {
658 	struct mipi_dsi_msg msg = {
659 		.channel = dsi->channel,
660 		.tx_buf = data,
661 		.tx_len = len
662 	};
663 
664 	switch (len) {
665 	case 0:
666 		return -EINVAL;
667 
668 	case 1:
669 		msg.type = MIPI_DSI_DCS_SHORT_WRITE;
670 		break;
671 
672 	case 2:
673 		msg.type = MIPI_DSI_DCS_SHORT_WRITE_PARAM;
674 		break;
675 
676 	default:
677 		msg.type = MIPI_DSI_DCS_LONG_WRITE;
678 		break;
679 	}
680 
681 	return mipi_dsi_device_transfer(dsi, &msg);
682 }
683 EXPORT_SYMBOL(mipi_dsi_dcs_write_buffer);
684 
685 /**
686  * mipi_dsi_dcs_write() - send DCS write command
687  * @dsi: DSI peripheral device
688  * @cmd: DCS command
689  * @data: buffer containing the command payload
690  * @len: command payload length
691  *
692  * This function will automatically choose the right data type depending on
693  * the command payload length.
694  *
695  * Return: The number of bytes successfully transmitted or a negative error
696  * code on failure.
697  */
698 ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, u8 cmd,
699 			   const void *data, size_t len)
700 {
701 	ssize_t err;
702 	size_t size;
703 	u8 *tx;
704 
705 	if (len > 0) {
706 		size = 1 + len;
707 
708 		tx = kmalloc(size, GFP_KERNEL);
709 		if (!tx)
710 			return -ENOMEM;
711 
712 		/* concatenate the DCS command byte and the payload */
713 		tx[0] = cmd;
714 		memcpy(&tx[1], data, len);
715 	} else {
716 		tx = &cmd;
717 		size = 1;
718 	}
719 
720 	err = mipi_dsi_dcs_write_buffer(dsi, tx, size);
721 
722 	if (len > 0)
723 		kfree(tx);
724 
725 	return err;
726 }
727 EXPORT_SYMBOL(mipi_dsi_dcs_write);
728 
729 /**
730  * mipi_dsi_dcs_read() - send DCS read request command
731  * @dsi: DSI peripheral device
732  * @cmd: DCS command
733  * @data: buffer in which to receive data
734  * @len: size of receive buffer
735  *
736  * Return: The number of bytes read or a negative error code on failure.
737  */
738 ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data,
739 			  size_t len)
740 {
741 	struct mipi_dsi_msg msg = {
742 		.channel = dsi->channel,
743 		.type = MIPI_DSI_DCS_READ,
744 		.tx_buf = &cmd,
745 		.tx_len = 1,
746 		.rx_buf = data,
747 		.rx_len = len
748 	};
749 
750 	return mipi_dsi_device_transfer(dsi, &msg);
751 }
752 EXPORT_SYMBOL(mipi_dsi_dcs_read);
753 
754 /**
755  * mipi_dsi_dcs_nop() - send DCS nop packet
756  * @dsi: DSI peripheral device
757  *
758  * Return: 0 on success or a negative error code on failure.
759  */
760 int mipi_dsi_dcs_nop(struct mipi_dsi_device *dsi)
761 {
762 	ssize_t err;
763 
764 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_NOP, NULL, 0);
765 	if (err < 0)
766 		return err;
767 
768 	return 0;
769 }
770 EXPORT_SYMBOL(mipi_dsi_dcs_nop);
771 
772 /**
773  * mipi_dsi_dcs_soft_reset() - perform a software reset of the display module
774  * @dsi: DSI peripheral device
775  *
776  * Return: 0 on success or a negative error code on failure.
777  */
778 int mipi_dsi_dcs_soft_reset(struct mipi_dsi_device *dsi)
779 {
780 	ssize_t err;
781 
782 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SOFT_RESET, NULL, 0);
783 	if (err < 0)
784 		return err;
785 
786 	return 0;
787 }
788 EXPORT_SYMBOL(mipi_dsi_dcs_soft_reset);
789 
790 /**
791  * mipi_dsi_dcs_get_power_mode() - query the display module's current power
792  *    mode
793  * @dsi: DSI peripheral device
794  * @mode: return location for the current power mode
795  *
796  * Return: 0 on success or a negative error code on failure.
797  */
798 int mipi_dsi_dcs_get_power_mode(struct mipi_dsi_device *dsi, u8 *mode)
799 {
800 	ssize_t err;
801 
802 	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_POWER_MODE, mode,
803 				sizeof(*mode));
804 	if (err <= 0) {
805 		if (err == 0)
806 			err = -ENODATA;
807 
808 		return err;
809 	}
810 
811 	return 0;
812 }
813 EXPORT_SYMBOL(mipi_dsi_dcs_get_power_mode);
814 
815 /**
816  * mipi_dsi_dcs_get_pixel_format() - gets the pixel format for the RGB image
817  *    data used by the interface
818  * @dsi: DSI peripheral device
819  * @format: return location for the pixel format
820  *
821  * Return: 0 on success or a negative error code on failure.
822  */
823 int mipi_dsi_dcs_get_pixel_format(struct mipi_dsi_device *dsi, u8 *format)
824 {
825 	ssize_t err;
826 
827 	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_PIXEL_FORMAT, format,
828 				sizeof(*format));
829 	if (err <= 0) {
830 		if (err == 0)
831 			err = -ENODATA;
832 
833 		return err;
834 	}
835 
836 	return 0;
837 }
838 EXPORT_SYMBOL(mipi_dsi_dcs_get_pixel_format);
839 
840 /**
841  * mipi_dsi_dcs_enter_sleep_mode() - disable all unnecessary blocks inside the
842  *    display module except interface communication
843  * @dsi: DSI peripheral device
844  *
845  * Return: 0 on success or a negative error code on failure.
846  */
847 int mipi_dsi_dcs_enter_sleep_mode(struct mipi_dsi_device *dsi)
848 {
849 	ssize_t err;
850 
851 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_ENTER_SLEEP_MODE, NULL, 0);
852 	if (err < 0)
853 		return err;
854 
855 	return 0;
856 }
857 EXPORT_SYMBOL(mipi_dsi_dcs_enter_sleep_mode);
858 
859 /**
860  * mipi_dsi_dcs_exit_sleep_mode() - enable all blocks inside the display
861  *    module
862  * @dsi: DSI peripheral device
863  *
864  * Return: 0 on success or a negative error code on failure.
865  */
866 int mipi_dsi_dcs_exit_sleep_mode(struct mipi_dsi_device *dsi)
867 {
868 	ssize_t err;
869 
870 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_EXIT_SLEEP_MODE, NULL, 0);
871 	if (err < 0)
872 		return err;
873 
874 	return 0;
875 }
876 EXPORT_SYMBOL(mipi_dsi_dcs_exit_sleep_mode);
877 
878 /**
879  * mipi_dsi_dcs_set_display_off() - stop displaying the image data on the
880  *    display device
881  * @dsi: DSI peripheral device
882  *
883  * Return: 0 on success or a negative error code on failure.
884  */
885 int mipi_dsi_dcs_set_display_off(struct mipi_dsi_device *dsi)
886 {
887 	ssize_t err;
888 
889 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_OFF, NULL, 0);
890 	if (err < 0)
891 		return err;
892 
893 	return 0;
894 }
895 EXPORT_SYMBOL(mipi_dsi_dcs_set_display_off);
896 
897 /**
898  * mipi_dsi_dcs_set_display_on() - start displaying the image data on the
899  *    display device
900  * @dsi: DSI peripheral device
901  *
902  * Return: 0 on success or a negative error code on failure
903  */
904 int mipi_dsi_dcs_set_display_on(struct mipi_dsi_device *dsi)
905 {
906 	ssize_t err;
907 
908 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_ON, NULL, 0);
909 	if (err < 0)
910 		return err;
911 
912 	return 0;
913 }
914 EXPORT_SYMBOL(mipi_dsi_dcs_set_display_on);
915 
916 /**
917  * mipi_dsi_dcs_set_column_address() - define the column extent of the frame
918  *    memory accessed by the host processor
919  * @dsi: DSI peripheral device
920  * @start: first column of frame memory
921  * @end: last column of frame memory
922  *
923  * Return: 0 on success or a negative error code on failure.
924  */
925 int mipi_dsi_dcs_set_column_address(struct mipi_dsi_device *dsi, u16 start,
926 				    u16 end)
927 {
928 	u8 payload[4] = { start >> 8, start & 0xff, end >> 8, end & 0xff };
929 	ssize_t err;
930 
931 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_COLUMN_ADDRESS, payload,
932 				 sizeof(payload));
933 	if (err < 0)
934 		return err;
935 
936 	return 0;
937 }
938 EXPORT_SYMBOL(mipi_dsi_dcs_set_column_address);
939 
940 /**
941  * mipi_dsi_dcs_set_page_address() - define the page extent of the frame
942  *    memory accessed by the host processor
943  * @dsi: DSI peripheral device
944  * @start: first page of frame memory
945  * @end: last page of frame memory
946  *
947  * Return: 0 on success or a negative error code on failure.
948  */
949 int mipi_dsi_dcs_set_page_address(struct mipi_dsi_device *dsi, u16 start,
950 				  u16 end)
951 {
952 	u8 payload[4] = { start >> 8, start & 0xff, end >> 8, end & 0xff };
953 	ssize_t err;
954 
955 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_PAGE_ADDRESS, payload,
956 				 sizeof(payload));
957 	if (err < 0)
958 		return err;
959 
960 	return 0;
961 }
962 EXPORT_SYMBOL(mipi_dsi_dcs_set_page_address);
963 
964 /**
965  * mipi_dsi_dcs_set_tear_off() - turn off the display module's Tearing Effect
966  *    output signal on the TE signal line
967  * @dsi: DSI peripheral device
968  *
969  * Return: 0 on success or a negative error code on failure
970  */
971 int mipi_dsi_dcs_set_tear_off(struct mipi_dsi_device *dsi)
972 {
973 	ssize_t err;
974 
975 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_TEAR_OFF, NULL, 0);
976 	if (err < 0)
977 		return err;
978 
979 	return 0;
980 }
981 EXPORT_SYMBOL(mipi_dsi_dcs_set_tear_off);
982 
983 /**
984  * mipi_dsi_dcs_set_tear_on() - turn on the display module's Tearing Effect
985  *    output signal on the TE signal line.
986  * @dsi: DSI peripheral device
987  * @mode: the Tearing Effect Output Line mode
988  *
989  * Return: 0 on success or a negative error code on failure
990  */
991 int mipi_dsi_dcs_set_tear_on(struct mipi_dsi_device *dsi,
992 			     enum mipi_dsi_dcs_tear_mode mode)
993 {
994 	u8 value = mode;
995 	ssize_t err;
996 
997 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_TEAR_ON, &value,
998 				 sizeof(value));
999 	if (err < 0)
1000 		return err;
1001 
1002 	return 0;
1003 }
1004 EXPORT_SYMBOL(mipi_dsi_dcs_set_tear_on);
1005 
1006 /**
1007  * mipi_dsi_dcs_set_pixel_format() - sets the pixel format for the RGB image
1008  *    data used by the interface
1009  * @dsi: DSI peripheral device
1010  * @format: pixel format
1011  *
1012  * Return: 0 on success or a negative error code on failure.
1013  */
1014 int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format)
1015 {
1016 	ssize_t err;
1017 
1018 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_PIXEL_FORMAT, &format,
1019 				 sizeof(format));
1020 	if (err < 0)
1021 		return err;
1022 
1023 	return 0;
1024 }
1025 EXPORT_SYMBOL(mipi_dsi_dcs_set_pixel_format);
1026 
1027 /**
1028  * mipi_dsi_dcs_set_tear_scanline() - set the scanline to use as trigger for
1029  *    the Tearing Effect output signal of the display module
1030  * @dsi: DSI peripheral device
1031  * @scanline: scanline to use as trigger
1032  *
1033  * Return: 0 on success or a negative error code on failure
1034  */
1035 int mipi_dsi_dcs_set_tear_scanline(struct mipi_dsi_device *dsi, u16 scanline)
1036 {
1037 	u8 payload[3] = { MIPI_DCS_SET_TEAR_SCANLINE, scanline >> 8,
1038 			  scanline & 0xff };
1039 	ssize_t err;
1040 
1041 	err = mipi_dsi_generic_write(dsi, payload, sizeof(payload));
1042 	if (err < 0)
1043 		return err;
1044 
1045 	return 0;
1046 }
1047 EXPORT_SYMBOL(mipi_dsi_dcs_set_tear_scanline);
1048 
1049 /**
1050  * mipi_dsi_dcs_set_display_brightness() - sets the brightness value of the
1051  *    display
1052  * @dsi: DSI peripheral device
1053  * @brightness: brightness value
1054  *
1055  * Return: 0 on success or a negative error code on failure.
1056  */
1057 int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
1058 					u16 brightness)
1059 {
1060 	u8 payload[2] = { brightness & 0xff, brightness >> 8 };
1061 	ssize_t err;
1062 
1063 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
1064 				 payload, sizeof(payload));
1065 	if (err < 0)
1066 		return err;
1067 
1068 	return 0;
1069 }
1070 EXPORT_SYMBOL(mipi_dsi_dcs_set_display_brightness);
1071 
1072 /**
1073  * mipi_dsi_dcs_get_display_brightness() - gets the current brightness value
1074  *    of the display
1075  * @dsi: DSI peripheral device
1076  * @brightness: brightness value
1077  *
1078  * Return: 0 on success or a negative error code on failure.
1079  */
1080 int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
1081 					u16 *brightness)
1082 {
1083 	ssize_t err;
1084 
1085 	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
1086 				brightness, sizeof(*brightness));
1087 	if (err <= 0) {
1088 		if (err == 0)
1089 			err = -ENODATA;
1090 
1091 		return err;
1092 	}
1093 
1094 	return 0;
1095 }
1096 EXPORT_SYMBOL(mipi_dsi_dcs_get_display_brightness);
1097 
1098 static int mipi_dsi_drv_probe(struct device *dev)
1099 {
1100 	struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
1101 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(dev);
1102 
1103 	return drv->probe(dsi);
1104 }
1105 
1106 static int mipi_dsi_drv_remove(struct device *dev)
1107 {
1108 	struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
1109 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(dev);
1110 
1111 	return drv->remove(dsi);
1112 }
1113 
1114 static void mipi_dsi_drv_shutdown(struct device *dev)
1115 {
1116 	struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
1117 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(dev);
1118 
1119 	drv->shutdown(dsi);
1120 }
1121 
1122 /**
1123  * mipi_dsi_driver_register_full() - register a driver for DSI devices
1124  * @drv: DSI driver structure
1125  * @owner: owner module
1126  *
1127  * Return: 0 on success or a negative error code on failure.
1128  */
1129 int mipi_dsi_driver_register_full(struct mipi_dsi_driver *drv,
1130 				  struct module *owner)
1131 {
1132 	drv->driver.bus = &mipi_dsi_bus_type;
1133 	drv->driver.owner = owner;
1134 
1135 	if (drv->probe)
1136 		drv->driver.probe = mipi_dsi_drv_probe;
1137 	if (drv->remove)
1138 		drv->driver.remove = mipi_dsi_drv_remove;
1139 	if (drv->shutdown)
1140 		drv->driver.shutdown = mipi_dsi_drv_shutdown;
1141 
1142 	return driver_register(&drv->driver);
1143 }
1144 EXPORT_SYMBOL(mipi_dsi_driver_register_full);
1145 
1146 /**
1147  * mipi_dsi_driver_unregister() - unregister a driver for DSI devices
1148  * @drv: DSI driver structure
1149  *
1150  * Return: 0 on success or a negative error code on failure.
1151  */
1152 void mipi_dsi_driver_unregister(struct mipi_dsi_driver *drv)
1153 {
1154 	driver_unregister(&drv->driver);
1155 }
1156 EXPORT_SYMBOL(mipi_dsi_driver_unregister);
1157 
1158 static int __init mipi_dsi_bus_init(void)
1159 {
1160 	return bus_register(&mipi_dsi_bus_type);
1161 }
1162 postcore_initcall(mipi_dsi_bus_init);
1163 
1164 MODULE_AUTHOR("Andrzej Hajda <a.hajda@samsung.com>");
1165 MODULE_DESCRIPTION("MIPI DSI Bus");
1166 MODULE_LICENSE("GPL and additional rights");
1167