xref: /openbmc/linux/drivers/gpu/drm/drm_mipi_dsi.c (revision 65417d9f)
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_SET_MAXIMUM_RETURN_PACKET_SIZE:
396 		return true;
397 	}
398 
399 	return false;
400 }
401 EXPORT_SYMBOL(mipi_dsi_packet_format_is_short);
402 
403 /**
404  * mipi_dsi_packet_format_is_long - check if a packet is of the long format
405  * @type: MIPI DSI data type of the packet
406  *
407  * Return: true if the packet for the given data type is a long packet, false
408  * otherwise.
409  */
410 bool mipi_dsi_packet_format_is_long(u8 type)
411 {
412 	switch (type) {
413 	case MIPI_DSI_NULL_PACKET:
414 	case MIPI_DSI_BLANKING_PACKET:
415 	case MIPI_DSI_GENERIC_LONG_WRITE:
416 	case MIPI_DSI_DCS_LONG_WRITE:
417 	case MIPI_DSI_LOOSELY_PACKED_PIXEL_STREAM_YCBCR20:
418 	case MIPI_DSI_PACKED_PIXEL_STREAM_YCBCR24:
419 	case MIPI_DSI_PACKED_PIXEL_STREAM_YCBCR16:
420 	case MIPI_DSI_PACKED_PIXEL_STREAM_30:
421 	case MIPI_DSI_PACKED_PIXEL_STREAM_36:
422 	case MIPI_DSI_PACKED_PIXEL_STREAM_YCBCR12:
423 	case MIPI_DSI_PACKED_PIXEL_STREAM_16:
424 	case MIPI_DSI_PACKED_PIXEL_STREAM_18:
425 	case MIPI_DSI_PIXEL_STREAM_3BYTE_18:
426 	case MIPI_DSI_PACKED_PIXEL_STREAM_24:
427 		return true;
428 	}
429 
430 	return false;
431 }
432 EXPORT_SYMBOL(mipi_dsi_packet_format_is_long);
433 
434 /**
435  * mipi_dsi_create_packet - create a packet from a message according to the
436  *     DSI protocol
437  * @packet: pointer to a DSI packet structure
438  * @msg: message to translate into a packet
439  *
440  * Return: 0 on success or a negative error code on failure.
441  */
442 int mipi_dsi_create_packet(struct mipi_dsi_packet *packet,
443 			   const struct mipi_dsi_msg *msg)
444 {
445 	if (!packet || !msg)
446 		return -EINVAL;
447 
448 	/* do some minimum sanity checking */
449 	if (!mipi_dsi_packet_format_is_short(msg->type) &&
450 	    !mipi_dsi_packet_format_is_long(msg->type))
451 		return -EINVAL;
452 
453 	if (msg->channel > 3)
454 		return -EINVAL;
455 
456 	memset(packet, 0, sizeof(*packet));
457 	packet->header[0] = ((msg->channel & 0x3) << 6) | (msg->type & 0x3f);
458 
459 	/* TODO: compute ECC if hardware support is not available */
460 
461 	/*
462 	 * Long write packets contain the word count in header bytes 1 and 2.
463 	 * The payload follows the header and is word count bytes long.
464 	 *
465 	 * Short write packets encode up to two parameters in header bytes 1
466 	 * and 2.
467 	 */
468 	if (mipi_dsi_packet_format_is_long(msg->type)) {
469 		packet->header[1] = (msg->tx_len >> 0) & 0xff;
470 		packet->header[2] = (msg->tx_len >> 8) & 0xff;
471 
472 		packet->payload_length = msg->tx_len;
473 		packet->payload = msg->tx_buf;
474 	} else {
475 		const u8 *tx = msg->tx_buf;
476 
477 		packet->header[1] = (msg->tx_len > 0) ? tx[0] : 0;
478 		packet->header[2] = (msg->tx_len > 1) ? tx[1] : 0;
479 	}
480 
481 	packet->size = sizeof(packet->header) + packet->payload_length;
482 
483 	return 0;
484 }
485 EXPORT_SYMBOL(mipi_dsi_create_packet);
486 
487 /**
488  * mipi_dsi_shutdown_peripheral() - sends a Shutdown Peripheral command
489  * @dsi: DSI peripheral device
490  *
491  * Return: 0 on success or a negative error code on failure.
492  */
493 int mipi_dsi_shutdown_peripheral(struct mipi_dsi_device *dsi)
494 {
495 	struct mipi_dsi_msg msg = {
496 		.channel = dsi->channel,
497 		.type = MIPI_DSI_SHUTDOWN_PERIPHERAL,
498 		.tx_buf = (u8 [2]) { 0, 0 },
499 		.tx_len = 2,
500 	};
501 
502 	return mipi_dsi_device_transfer(dsi, &msg);
503 }
504 EXPORT_SYMBOL(mipi_dsi_shutdown_peripheral);
505 
506 /**
507  * mipi_dsi_turn_on_peripheral() - sends a Turn On Peripheral command
508  * @dsi: DSI peripheral device
509  *
510  * Return: 0 on success or a negative error code on failure.
511  */
512 int mipi_dsi_turn_on_peripheral(struct mipi_dsi_device *dsi)
513 {
514 	struct mipi_dsi_msg msg = {
515 		.channel = dsi->channel,
516 		.type = MIPI_DSI_TURN_ON_PERIPHERAL,
517 		.tx_buf = (u8 [2]) { 0, 0 },
518 		.tx_len = 2,
519 	};
520 
521 	return mipi_dsi_device_transfer(dsi, &msg);
522 }
523 EXPORT_SYMBOL(mipi_dsi_turn_on_peripheral);
524 
525 /*
526  * mipi_dsi_set_maximum_return_packet_size() - specify the maximum size of the
527  *    the payload in a long packet transmitted from the peripheral back to the
528  *    host processor
529  * @dsi: DSI peripheral device
530  * @value: the maximum size of the payload
531  *
532  * Return: 0 on success or a negative error code on failure.
533  */
534 int mipi_dsi_set_maximum_return_packet_size(struct mipi_dsi_device *dsi,
535 					    u16 value)
536 {
537 	u8 tx[2] = { value & 0xff, value >> 8 };
538 	struct mipi_dsi_msg msg = {
539 		.channel = dsi->channel,
540 		.type = MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE,
541 		.tx_len = sizeof(tx),
542 		.tx_buf = tx,
543 	};
544 
545 	return mipi_dsi_device_transfer(dsi, &msg);
546 }
547 EXPORT_SYMBOL(mipi_dsi_set_maximum_return_packet_size);
548 
549 /**
550  * mipi_dsi_generic_write() - transmit data using a generic write packet
551  * @dsi: DSI peripheral device
552  * @payload: buffer containing the payload
553  * @size: size of payload buffer
554  *
555  * This function will automatically choose the right data type depending on
556  * the payload length.
557  *
558  * Return: The number of bytes transmitted on success or a negative error code
559  * on failure.
560  */
561 ssize_t mipi_dsi_generic_write(struct mipi_dsi_device *dsi, const void *payload,
562 			       size_t size)
563 {
564 	struct mipi_dsi_msg msg = {
565 		.channel = dsi->channel,
566 		.tx_buf = payload,
567 		.tx_len = size
568 	};
569 
570 	switch (size) {
571 	case 0:
572 		msg.type = MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM;
573 		break;
574 
575 	case 1:
576 		msg.type = MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM;
577 		break;
578 
579 	case 2:
580 		msg.type = MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM;
581 		break;
582 
583 	default:
584 		msg.type = MIPI_DSI_GENERIC_LONG_WRITE;
585 		break;
586 	}
587 
588 	return mipi_dsi_device_transfer(dsi, &msg);
589 }
590 EXPORT_SYMBOL(mipi_dsi_generic_write);
591 
592 /**
593  * mipi_dsi_generic_read() - receive data using a generic read packet
594  * @dsi: DSI peripheral device
595  * @params: buffer containing the request parameters
596  * @num_params: number of request parameters
597  * @data: buffer in which to return the received data
598  * @size: size of receive buffer
599  *
600  * This function will automatically choose the right data type depending on
601  * the number of parameters passed in.
602  *
603  * Return: The number of bytes successfully read or a negative error code on
604  * failure.
605  */
606 ssize_t mipi_dsi_generic_read(struct mipi_dsi_device *dsi, const void *params,
607 			      size_t num_params, void *data, size_t size)
608 {
609 	struct mipi_dsi_msg msg = {
610 		.channel = dsi->channel,
611 		.tx_len = num_params,
612 		.tx_buf = params,
613 		.rx_len = size,
614 		.rx_buf = data
615 	};
616 
617 	switch (num_params) {
618 	case 0:
619 		msg.type = MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM;
620 		break;
621 
622 	case 1:
623 		msg.type = MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM;
624 		break;
625 
626 	case 2:
627 		msg.type = MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM;
628 		break;
629 
630 	default:
631 		return -EINVAL;
632 	}
633 
634 	return mipi_dsi_device_transfer(dsi, &msg);
635 }
636 EXPORT_SYMBOL(mipi_dsi_generic_read);
637 
638 /**
639  * mipi_dsi_dcs_write_buffer() - transmit a DCS command with payload
640  * @dsi: DSI peripheral device
641  * @data: buffer containing data to be transmitted
642  * @len: size of transmission buffer
643  *
644  * This function will automatically choose the right data type depending on
645  * the command payload length.
646  *
647  * Return: The number of bytes successfully transmitted or a negative error
648  * code on failure.
649  */
650 ssize_t mipi_dsi_dcs_write_buffer(struct mipi_dsi_device *dsi,
651 				  const void *data, size_t len)
652 {
653 	struct mipi_dsi_msg msg = {
654 		.channel = dsi->channel,
655 		.tx_buf = data,
656 		.tx_len = len
657 	};
658 
659 	switch (len) {
660 	case 0:
661 		return -EINVAL;
662 
663 	case 1:
664 		msg.type = MIPI_DSI_DCS_SHORT_WRITE;
665 		break;
666 
667 	case 2:
668 		msg.type = MIPI_DSI_DCS_SHORT_WRITE_PARAM;
669 		break;
670 
671 	default:
672 		msg.type = MIPI_DSI_DCS_LONG_WRITE;
673 		break;
674 	}
675 
676 	return mipi_dsi_device_transfer(dsi, &msg);
677 }
678 EXPORT_SYMBOL(mipi_dsi_dcs_write_buffer);
679 
680 /**
681  * mipi_dsi_dcs_write() - send DCS write command
682  * @dsi: DSI peripheral device
683  * @cmd: DCS command
684  * @data: buffer containing the command payload
685  * @len: command payload length
686  *
687  * This function will automatically choose the right data type depending on
688  * the command payload length.
689  *
690  * Return: The number of bytes successfully transmitted or a negative error
691  * code on failure.
692  */
693 ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, u8 cmd,
694 			   const void *data, size_t len)
695 {
696 	ssize_t err;
697 	size_t size;
698 	u8 *tx;
699 
700 	if (len > 0) {
701 		size = 1 + len;
702 
703 		tx = kmalloc(size, GFP_KERNEL);
704 		if (!tx)
705 			return -ENOMEM;
706 
707 		/* concatenate the DCS command byte and the payload */
708 		tx[0] = cmd;
709 		memcpy(&tx[1], data, len);
710 	} else {
711 		tx = &cmd;
712 		size = 1;
713 	}
714 
715 	err = mipi_dsi_dcs_write_buffer(dsi, tx, size);
716 
717 	if (len > 0)
718 		kfree(tx);
719 
720 	return err;
721 }
722 EXPORT_SYMBOL(mipi_dsi_dcs_write);
723 
724 /**
725  * mipi_dsi_dcs_read() - send DCS read request command
726  * @dsi: DSI peripheral device
727  * @cmd: DCS command
728  * @data: buffer in which to receive data
729  * @len: size of receive buffer
730  *
731  * Return: The number of bytes read or a negative error code on failure.
732  */
733 ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data,
734 			  size_t len)
735 {
736 	struct mipi_dsi_msg msg = {
737 		.channel = dsi->channel,
738 		.type = MIPI_DSI_DCS_READ,
739 		.tx_buf = &cmd,
740 		.tx_len = 1,
741 		.rx_buf = data,
742 		.rx_len = len
743 	};
744 
745 	return mipi_dsi_device_transfer(dsi, &msg);
746 }
747 EXPORT_SYMBOL(mipi_dsi_dcs_read);
748 
749 /**
750  * mipi_dsi_dcs_nop() - send DCS nop packet
751  * @dsi: DSI peripheral device
752  *
753  * Return: 0 on success or a negative error code on failure.
754  */
755 int mipi_dsi_dcs_nop(struct mipi_dsi_device *dsi)
756 {
757 	ssize_t err;
758 
759 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_NOP, NULL, 0);
760 	if (err < 0)
761 		return err;
762 
763 	return 0;
764 }
765 EXPORT_SYMBOL(mipi_dsi_dcs_nop);
766 
767 /**
768  * mipi_dsi_dcs_soft_reset() - perform a software reset of the display module
769  * @dsi: DSI peripheral device
770  *
771  * Return: 0 on success or a negative error code on failure.
772  */
773 int mipi_dsi_dcs_soft_reset(struct mipi_dsi_device *dsi)
774 {
775 	ssize_t err;
776 
777 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SOFT_RESET, NULL, 0);
778 	if (err < 0)
779 		return err;
780 
781 	return 0;
782 }
783 EXPORT_SYMBOL(mipi_dsi_dcs_soft_reset);
784 
785 /**
786  * mipi_dsi_dcs_get_power_mode() - query the display module's current power
787  *    mode
788  * @dsi: DSI peripheral device
789  * @mode: return location for the current power mode
790  *
791  * Return: 0 on success or a negative error code on failure.
792  */
793 int mipi_dsi_dcs_get_power_mode(struct mipi_dsi_device *dsi, u8 *mode)
794 {
795 	ssize_t err;
796 
797 	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_POWER_MODE, mode,
798 				sizeof(*mode));
799 	if (err <= 0) {
800 		if (err == 0)
801 			err = -ENODATA;
802 
803 		return err;
804 	}
805 
806 	return 0;
807 }
808 EXPORT_SYMBOL(mipi_dsi_dcs_get_power_mode);
809 
810 /**
811  * mipi_dsi_dcs_get_pixel_format() - gets the pixel format for the RGB image
812  *    data used by the interface
813  * @dsi: DSI peripheral device
814  * @format: return location for the pixel format
815  *
816  * Return: 0 on success or a negative error code on failure.
817  */
818 int mipi_dsi_dcs_get_pixel_format(struct mipi_dsi_device *dsi, u8 *format)
819 {
820 	ssize_t err;
821 
822 	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_PIXEL_FORMAT, format,
823 				sizeof(*format));
824 	if (err <= 0) {
825 		if (err == 0)
826 			err = -ENODATA;
827 
828 		return err;
829 	}
830 
831 	return 0;
832 }
833 EXPORT_SYMBOL(mipi_dsi_dcs_get_pixel_format);
834 
835 /**
836  * mipi_dsi_dcs_enter_sleep_mode() - disable all unnecessary blocks inside the
837  *    display module except interface communication
838  * @dsi: DSI peripheral device
839  *
840  * Return: 0 on success or a negative error code on failure.
841  */
842 int mipi_dsi_dcs_enter_sleep_mode(struct mipi_dsi_device *dsi)
843 {
844 	ssize_t err;
845 
846 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_ENTER_SLEEP_MODE, NULL, 0);
847 	if (err < 0)
848 		return err;
849 
850 	return 0;
851 }
852 EXPORT_SYMBOL(mipi_dsi_dcs_enter_sleep_mode);
853 
854 /**
855  * mipi_dsi_dcs_exit_sleep_mode() - enable all blocks inside the display
856  *    module
857  * @dsi: DSI peripheral device
858  *
859  * Return: 0 on success or a negative error code on failure.
860  */
861 int mipi_dsi_dcs_exit_sleep_mode(struct mipi_dsi_device *dsi)
862 {
863 	ssize_t err;
864 
865 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_EXIT_SLEEP_MODE, NULL, 0);
866 	if (err < 0)
867 		return err;
868 
869 	return 0;
870 }
871 EXPORT_SYMBOL(mipi_dsi_dcs_exit_sleep_mode);
872 
873 /**
874  * mipi_dsi_dcs_set_display_off() - stop displaying the image data on the
875  *    display device
876  * @dsi: DSI peripheral device
877  *
878  * Return: 0 on success or a negative error code on failure.
879  */
880 int mipi_dsi_dcs_set_display_off(struct mipi_dsi_device *dsi)
881 {
882 	ssize_t err;
883 
884 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_OFF, NULL, 0);
885 	if (err < 0)
886 		return err;
887 
888 	return 0;
889 }
890 EXPORT_SYMBOL(mipi_dsi_dcs_set_display_off);
891 
892 /**
893  * mipi_dsi_dcs_set_display_on() - start displaying the image data on the
894  *    display device
895  * @dsi: DSI peripheral device
896  *
897  * Return: 0 on success or a negative error code on failure
898  */
899 int mipi_dsi_dcs_set_display_on(struct mipi_dsi_device *dsi)
900 {
901 	ssize_t err;
902 
903 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_ON, NULL, 0);
904 	if (err < 0)
905 		return err;
906 
907 	return 0;
908 }
909 EXPORT_SYMBOL(mipi_dsi_dcs_set_display_on);
910 
911 /**
912  * mipi_dsi_dcs_set_column_address() - define the column extent of the frame
913  *    memory accessed by the host processor
914  * @dsi: DSI peripheral device
915  * @start: first column of frame memory
916  * @end: last column of frame memory
917  *
918  * Return: 0 on success or a negative error code on failure.
919  */
920 int mipi_dsi_dcs_set_column_address(struct mipi_dsi_device *dsi, u16 start,
921 				    u16 end)
922 {
923 	u8 payload[4] = { start >> 8, start & 0xff, end >> 8, end & 0xff };
924 	ssize_t err;
925 
926 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_COLUMN_ADDRESS, payload,
927 				 sizeof(payload));
928 	if (err < 0)
929 		return err;
930 
931 	return 0;
932 }
933 EXPORT_SYMBOL(mipi_dsi_dcs_set_column_address);
934 
935 /**
936  * mipi_dsi_dcs_set_page_address() - define the page extent of the frame
937  *    memory accessed by the host processor
938  * @dsi: DSI peripheral device
939  * @start: first page of frame memory
940  * @end: last page of frame memory
941  *
942  * Return: 0 on success or a negative error code on failure.
943  */
944 int mipi_dsi_dcs_set_page_address(struct mipi_dsi_device *dsi, u16 start,
945 				  u16 end)
946 {
947 	u8 payload[4] = { start >> 8, start & 0xff, end >> 8, end & 0xff };
948 	ssize_t err;
949 
950 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_PAGE_ADDRESS, payload,
951 				 sizeof(payload));
952 	if (err < 0)
953 		return err;
954 
955 	return 0;
956 }
957 EXPORT_SYMBOL(mipi_dsi_dcs_set_page_address);
958 
959 /**
960  * mipi_dsi_dcs_set_tear_off() - turn off the display module's Tearing Effect
961  *    output signal on the TE signal line
962  * @dsi: DSI peripheral device
963  *
964  * Return: 0 on success or a negative error code on failure
965  */
966 int mipi_dsi_dcs_set_tear_off(struct mipi_dsi_device *dsi)
967 {
968 	ssize_t err;
969 
970 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_TEAR_OFF, NULL, 0);
971 	if (err < 0)
972 		return err;
973 
974 	return 0;
975 }
976 EXPORT_SYMBOL(mipi_dsi_dcs_set_tear_off);
977 
978 /**
979  * mipi_dsi_dcs_set_tear_on() - turn on the display module's Tearing Effect
980  *    output signal on the TE signal line.
981  * @dsi: DSI peripheral device
982  * @mode: the Tearing Effect Output Line mode
983  *
984  * Return: 0 on success or a negative error code on failure
985  */
986 int mipi_dsi_dcs_set_tear_on(struct mipi_dsi_device *dsi,
987 			     enum mipi_dsi_dcs_tear_mode mode)
988 {
989 	u8 value = mode;
990 	ssize_t err;
991 
992 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_TEAR_ON, &value,
993 				 sizeof(value));
994 	if (err < 0)
995 		return err;
996 
997 	return 0;
998 }
999 EXPORT_SYMBOL(mipi_dsi_dcs_set_tear_on);
1000 
1001 /**
1002  * mipi_dsi_dcs_set_pixel_format() - sets the pixel format for the RGB image
1003  *    data used by the interface
1004  * @dsi: DSI peripheral device
1005  * @format: pixel format
1006  *
1007  * Return: 0 on success or a negative error code on failure.
1008  */
1009 int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format)
1010 {
1011 	ssize_t err;
1012 
1013 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_PIXEL_FORMAT, &format,
1014 				 sizeof(format));
1015 	if (err < 0)
1016 		return err;
1017 
1018 	return 0;
1019 }
1020 EXPORT_SYMBOL(mipi_dsi_dcs_set_pixel_format);
1021 
1022 /**
1023  * mipi_dsi_dcs_set_tear_scanline() - set the scanline to use as trigger for
1024  *    the Tearing Effect output signal of the display module
1025  * @dsi: DSI peripheral device
1026  * @scanline: scanline to use as trigger
1027  *
1028  * Return: 0 on success or a negative error code on failure
1029  */
1030 int mipi_dsi_dcs_set_tear_scanline(struct mipi_dsi_device *dsi, u16 scanline)
1031 {
1032 	u8 payload[3] = { MIPI_DCS_SET_TEAR_SCANLINE, scanline >> 8,
1033 			  scanline & 0xff };
1034 	ssize_t err;
1035 
1036 	err = mipi_dsi_generic_write(dsi, payload, sizeof(payload));
1037 	if (err < 0)
1038 		return err;
1039 
1040 	return 0;
1041 }
1042 EXPORT_SYMBOL(mipi_dsi_dcs_set_tear_scanline);
1043 
1044 /**
1045  * mipi_dsi_dcs_set_display_brightness() - sets the brightness value of the
1046  *    display
1047  * @dsi: DSI peripheral device
1048  * @brightness: brightness value
1049  *
1050  * Return: 0 on success or a negative error code on failure.
1051  */
1052 int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
1053 					u16 brightness)
1054 {
1055 	u8 payload[2] = { brightness & 0xff, brightness >> 8 };
1056 	ssize_t err;
1057 
1058 	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
1059 				 payload, sizeof(payload));
1060 	if (err < 0)
1061 		return err;
1062 
1063 	return 0;
1064 }
1065 EXPORT_SYMBOL(mipi_dsi_dcs_set_display_brightness);
1066 
1067 /**
1068  * mipi_dsi_dcs_get_display_brightness() - gets the current brightness value
1069  *    of the display
1070  * @dsi: DSI peripheral device
1071  * @brightness: brightness value
1072  *
1073  * Return: 0 on success or a negative error code on failure.
1074  */
1075 int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
1076 					u16 *brightness)
1077 {
1078 	ssize_t err;
1079 
1080 	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
1081 				brightness, sizeof(*brightness));
1082 	if (err <= 0) {
1083 		if (err == 0)
1084 			err = -ENODATA;
1085 
1086 		return err;
1087 	}
1088 
1089 	return 0;
1090 }
1091 EXPORT_SYMBOL(mipi_dsi_dcs_get_display_brightness);
1092 
1093 static int mipi_dsi_drv_probe(struct device *dev)
1094 {
1095 	struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
1096 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(dev);
1097 
1098 	return drv->probe(dsi);
1099 }
1100 
1101 static int mipi_dsi_drv_remove(struct device *dev)
1102 {
1103 	struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
1104 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(dev);
1105 
1106 	return drv->remove(dsi);
1107 }
1108 
1109 static void mipi_dsi_drv_shutdown(struct device *dev)
1110 {
1111 	struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
1112 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(dev);
1113 
1114 	drv->shutdown(dsi);
1115 }
1116 
1117 /**
1118  * mipi_dsi_driver_register_full() - register a driver for DSI devices
1119  * @drv: DSI driver structure
1120  * @owner: owner module
1121  *
1122  * Return: 0 on success or a negative error code on failure.
1123  */
1124 int mipi_dsi_driver_register_full(struct mipi_dsi_driver *drv,
1125 				  struct module *owner)
1126 {
1127 	drv->driver.bus = &mipi_dsi_bus_type;
1128 	drv->driver.owner = owner;
1129 
1130 	if (drv->probe)
1131 		drv->driver.probe = mipi_dsi_drv_probe;
1132 	if (drv->remove)
1133 		drv->driver.remove = mipi_dsi_drv_remove;
1134 	if (drv->shutdown)
1135 		drv->driver.shutdown = mipi_dsi_drv_shutdown;
1136 
1137 	return driver_register(&drv->driver);
1138 }
1139 EXPORT_SYMBOL(mipi_dsi_driver_register_full);
1140 
1141 /**
1142  * mipi_dsi_driver_unregister() - unregister a driver for DSI devices
1143  * @drv: DSI driver structure
1144  *
1145  * Return: 0 on success or a negative error code on failure.
1146  */
1147 void mipi_dsi_driver_unregister(struct mipi_dsi_driver *drv)
1148 {
1149 	driver_unregister(&drv->driver);
1150 }
1151 EXPORT_SYMBOL(mipi_dsi_driver_unregister);
1152 
1153 static int __init mipi_dsi_bus_init(void)
1154 {
1155 	return bus_register(&mipi_dsi_bus_type);
1156 }
1157 postcore_initcall(mipi_dsi_bus_init);
1158 
1159 MODULE_AUTHOR("Andrzej Hajda <a.hajda@samsung.com>");
1160 MODULE_DESCRIPTION("MIPI DSI Bus");
1161 MODULE_LICENSE("GPL and additional rights");
1162