xref: /linux/drivers/gpu/drm/drm_mipi_dbi.c (revision 3c4fc7bf4c9e66fe71abcbf93f62f4ddb89b7f15)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * MIPI Display Bus Interface (DBI) LCD controller support
4  *
5  * Copyright 2016 Noralf Trønnes
6  */
7 
8 #include <linux/backlight.h>
9 #include <linux/debugfs.h>
10 #include <linux/delay.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/module.h>
13 #include <linux/regulator/consumer.h>
14 #include <linux/spi/spi.h>
15 
16 #include <drm/drm_connector.h>
17 #include <drm/drm_damage_helper.h>
18 #include <drm/drm_drv.h>
19 #include <drm/drm_file.h>
20 #include <drm/drm_format_helper.h>
21 #include <drm/drm_fourcc.h>
22 #include <drm/drm_framebuffer.h>
23 #include <drm/drm_gem.h>
24 #include <drm/drm_gem_framebuffer_helper.h>
25 #include <drm/drm_mipi_dbi.h>
26 #include <drm/drm_modes.h>
27 #include <drm/drm_probe_helper.h>
28 #include <drm/drm_rect.h>
29 #include <video/mipi_display.h>
30 
31 #define MIPI_DBI_MAX_SPI_READ_SPEED 2000000 /* 2MHz */
32 
33 #define DCS_POWER_MODE_DISPLAY			BIT(2)
34 #define DCS_POWER_MODE_DISPLAY_NORMAL_MODE	BIT(3)
35 #define DCS_POWER_MODE_SLEEP_MODE		BIT(4)
36 #define DCS_POWER_MODE_PARTIAL_MODE		BIT(5)
37 #define DCS_POWER_MODE_IDLE_MODE		BIT(6)
38 #define DCS_POWER_MODE_RESERVED_MASK		(BIT(0) | BIT(1) | BIT(7))
39 
40 /**
41  * DOC: overview
42  *
43  * This library provides helpers for MIPI Display Bus Interface (DBI)
44  * compatible display controllers.
45  *
46  * Many controllers for tiny lcd displays are MIPI compliant and can use this
47  * library. If a controller uses registers 0x2A and 0x2B to set the area to
48  * update and uses register 0x2C to write to frame memory, it is most likely
49  * MIPI compliant.
50  *
51  * Only MIPI Type 1 displays are supported since a full frame memory is needed.
52  *
53  * There are 3 MIPI DBI implementation types:
54  *
55  * A. Motorola 6800 type parallel bus
56  *
57  * B. Intel 8080 type parallel bus
58  *
59  * C. SPI type with 3 options:
60  *
61  *    1. 9-bit with the Data/Command signal as the ninth bit
62  *    2. Same as above except it's sent as 16 bits
63  *    3. 8-bit with the Data/Command signal as a separate D/CX pin
64  *
65  * Currently mipi_dbi only supports Type C options 1 and 3 with
66  * mipi_dbi_spi_init().
67  */
68 
69 #define MIPI_DBI_DEBUG_COMMAND(cmd, data, len) \
70 ({ \
71 	if (!len) \
72 		DRM_DEBUG_DRIVER("cmd=%02x\n", cmd); \
73 	else if (len <= 32) \
74 		DRM_DEBUG_DRIVER("cmd=%02x, par=%*ph\n", cmd, (int)len, data);\
75 	else \
76 		DRM_DEBUG_DRIVER("cmd=%02x, len=%zu\n", cmd, len); \
77 })
78 
79 static const u8 mipi_dbi_dcs_read_commands[] = {
80 	MIPI_DCS_GET_DISPLAY_ID,
81 	MIPI_DCS_GET_RED_CHANNEL,
82 	MIPI_DCS_GET_GREEN_CHANNEL,
83 	MIPI_DCS_GET_BLUE_CHANNEL,
84 	MIPI_DCS_GET_DISPLAY_STATUS,
85 	MIPI_DCS_GET_POWER_MODE,
86 	MIPI_DCS_GET_ADDRESS_MODE,
87 	MIPI_DCS_GET_PIXEL_FORMAT,
88 	MIPI_DCS_GET_DISPLAY_MODE,
89 	MIPI_DCS_GET_SIGNAL_MODE,
90 	MIPI_DCS_GET_DIAGNOSTIC_RESULT,
91 	MIPI_DCS_READ_MEMORY_START,
92 	MIPI_DCS_READ_MEMORY_CONTINUE,
93 	MIPI_DCS_GET_SCANLINE,
94 	MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
95 	MIPI_DCS_GET_CONTROL_DISPLAY,
96 	MIPI_DCS_GET_POWER_SAVE,
97 	MIPI_DCS_GET_CABC_MIN_BRIGHTNESS,
98 	MIPI_DCS_READ_DDB_START,
99 	MIPI_DCS_READ_DDB_CONTINUE,
100 	0, /* sentinel */
101 };
102 
103 static bool mipi_dbi_command_is_read(struct mipi_dbi *dbi, u8 cmd)
104 {
105 	unsigned int i;
106 
107 	if (!dbi->read_commands)
108 		return false;
109 
110 	for (i = 0; i < 0xff; i++) {
111 		if (!dbi->read_commands[i])
112 			return false;
113 		if (cmd == dbi->read_commands[i])
114 			return true;
115 	}
116 
117 	return false;
118 }
119 
120 /**
121  * mipi_dbi_command_read - MIPI DCS read command
122  * @dbi: MIPI DBI structure
123  * @cmd: Command
124  * @val: Value read
125  *
126  * Send MIPI DCS read command to the controller.
127  *
128  * Returns:
129  * Zero on success, negative error code on failure.
130  */
131 int mipi_dbi_command_read(struct mipi_dbi *dbi, u8 cmd, u8 *val)
132 {
133 	if (!dbi->read_commands)
134 		return -EACCES;
135 
136 	if (!mipi_dbi_command_is_read(dbi, cmd))
137 		return -EINVAL;
138 
139 	return mipi_dbi_command_buf(dbi, cmd, val, 1);
140 }
141 EXPORT_SYMBOL(mipi_dbi_command_read);
142 
143 /**
144  * mipi_dbi_command_buf - MIPI DCS command with parameter(s) in an array
145  * @dbi: MIPI DBI structure
146  * @cmd: Command
147  * @data: Parameter buffer
148  * @len: Buffer length
149  *
150  * Returns:
151  * Zero on success, negative error code on failure.
152  */
153 int mipi_dbi_command_buf(struct mipi_dbi *dbi, u8 cmd, u8 *data, size_t len)
154 {
155 	u8 *cmdbuf;
156 	int ret;
157 
158 	/* SPI requires dma-safe buffers */
159 	cmdbuf = kmemdup(&cmd, 1, GFP_KERNEL);
160 	if (!cmdbuf)
161 		return -ENOMEM;
162 
163 	mutex_lock(&dbi->cmdlock);
164 	ret = dbi->command(dbi, cmdbuf, data, len);
165 	mutex_unlock(&dbi->cmdlock);
166 
167 	kfree(cmdbuf);
168 
169 	return ret;
170 }
171 EXPORT_SYMBOL(mipi_dbi_command_buf);
172 
173 /* This should only be used by mipi_dbi_command() */
174 int mipi_dbi_command_stackbuf(struct mipi_dbi *dbi, u8 cmd, const u8 *data,
175 			      size_t len)
176 {
177 	u8 *buf;
178 	int ret;
179 
180 	buf = kmemdup(data, len, GFP_KERNEL);
181 	if (!buf)
182 		return -ENOMEM;
183 
184 	ret = mipi_dbi_command_buf(dbi, cmd, buf, len);
185 
186 	kfree(buf);
187 
188 	return ret;
189 }
190 EXPORT_SYMBOL(mipi_dbi_command_stackbuf);
191 
192 /**
193  * mipi_dbi_buf_copy - Copy a framebuffer, transforming it if necessary
194  * @dst: The destination buffer
195  * @fb: The source framebuffer
196  * @clip: Clipping rectangle of the area to be copied
197  * @swap: When true, swap MSB/LSB of 16-bit values
198  *
199  * Returns:
200  * Zero on success, negative error code on failure.
201  */
202 int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
203 		      struct drm_rect *clip, bool swap)
204 {
205 	struct drm_gem_object *gem = drm_gem_fb_get_obj(fb, 0);
206 	struct iosys_map map[DRM_FORMAT_MAX_PLANES];
207 	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
208 	void *src;
209 	int ret;
210 
211 	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
212 	if (ret)
213 		return ret;
214 
215 	ret = drm_gem_fb_vmap(fb, map, data);
216 	if (ret)
217 		goto out_drm_gem_fb_end_cpu_access;
218 	src = data[0].vaddr; /* TODO: Use mapping abstraction properly */
219 
220 	switch (fb->format->format) {
221 	case DRM_FORMAT_RGB565:
222 		if (swap)
223 			drm_fb_swab(dst, 0, src, fb, clip, !gem->import_attach);
224 		else
225 			drm_fb_memcpy(dst, 0, src, fb, clip);
226 		break;
227 	case DRM_FORMAT_XRGB8888:
228 		drm_fb_xrgb8888_to_rgb565(dst, 0, src, fb, clip, swap);
229 		break;
230 	default:
231 		drm_err_once(fb->dev, "Format is not supported: %p4cc\n",
232 			     &fb->format->format);
233 		ret = -EINVAL;
234 	}
235 
236 	drm_gem_fb_vunmap(fb, map);
237 out_drm_gem_fb_end_cpu_access:
238 	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
239 
240 	return ret;
241 }
242 EXPORT_SYMBOL(mipi_dbi_buf_copy);
243 
244 static void mipi_dbi_set_window_address(struct mipi_dbi_dev *dbidev,
245 					unsigned int xs, unsigned int xe,
246 					unsigned int ys, unsigned int ye)
247 {
248 	struct mipi_dbi *dbi = &dbidev->dbi;
249 
250 	xs += dbidev->left_offset;
251 	xe += dbidev->left_offset;
252 	ys += dbidev->top_offset;
253 	ye += dbidev->top_offset;
254 
255 	mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS, (xs >> 8) & 0xff,
256 			 xs & 0xff, (xe >> 8) & 0xff, xe & 0xff);
257 	mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS, (ys >> 8) & 0xff,
258 			 ys & 0xff, (ye >> 8) & 0xff, ye & 0xff);
259 }
260 
261 static void mipi_dbi_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
262 {
263 	struct iosys_map map[DRM_FORMAT_MAX_PLANES];
264 	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
265 	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
266 	unsigned int height = rect->y2 - rect->y1;
267 	unsigned int width = rect->x2 - rect->x1;
268 	struct mipi_dbi *dbi = &dbidev->dbi;
269 	bool swap = dbi->swap_bytes;
270 	int idx, ret = 0;
271 	bool full;
272 	void *tr;
273 
274 	if (WARN_ON(!fb))
275 		return;
276 
277 	if (!drm_dev_enter(fb->dev, &idx))
278 		return;
279 
280 	ret = drm_gem_fb_vmap(fb, map, data);
281 	if (ret)
282 		goto err_drm_dev_exit;
283 
284 	full = width == fb->width && height == fb->height;
285 
286 	DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
287 
288 	if (!dbi->dc || !full || swap ||
289 	    fb->format->format == DRM_FORMAT_XRGB8888) {
290 		tr = dbidev->tx_buf;
291 		ret = mipi_dbi_buf_copy(dbidev->tx_buf, fb, rect, swap);
292 		if (ret)
293 			goto err_msg;
294 	} else {
295 		tr = data[0].vaddr; /* TODO: Use mapping abstraction properly */
296 	}
297 
298 	mipi_dbi_set_window_address(dbidev, rect->x1, rect->x2 - 1, rect->y1,
299 				    rect->y2 - 1);
300 
301 	ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START, tr,
302 				   width * height * 2);
303 err_msg:
304 	if (ret)
305 		drm_err_once(fb->dev, "Failed to update display %d\n", ret);
306 
307 	drm_gem_fb_vunmap(fb, map);
308 
309 err_drm_dev_exit:
310 	drm_dev_exit(idx);
311 }
312 
313 /**
314  * mipi_dbi_pipe_update - Display pipe update helper
315  * @pipe: Simple display pipe
316  * @old_state: Old plane state
317  *
318  * This function handles framebuffer flushing and vblank events. Drivers can use
319  * this as their &drm_simple_display_pipe_funcs->update callback.
320  */
321 void mipi_dbi_pipe_update(struct drm_simple_display_pipe *pipe,
322 			  struct drm_plane_state *old_state)
323 {
324 	struct drm_plane_state *state = pipe->plane.state;
325 	struct drm_rect rect;
326 
327 	if (!pipe->crtc.state->active)
328 		return;
329 
330 	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
331 		mipi_dbi_fb_dirty(state->fb, &rect);
332 }
333 EXPORT_SYMBOL(mipi_dbi_pipe_update);
334 
335 /**
336  * mipi_dbi_enable_flush - MIPI DBI enable helper
337  * @dbidev: MIPI DBI device structure
338  * @crtc_state: CRTC state
339  * @plane_state: Plane state
340  *
341  * Flushes the whole framebuffer and enables the backlight. Drivers can use this
342  * in their &drm_simple_display_pipe_funcs->enable callback.
343  *
344  * Note: Drivers which don't use mipi_dbi_pipe_update() because they have custom
345  * framebuffer flushing, can't use this function since they both use the same
346  * flushing code.
347  */
348 void mipi_dbi_enable_flush(struct mipi_dbi_dev *dbidev,
349 			   struct drm_crtc_state *crtc_state,
350 			   struct drm_plane_state *plane_state)
351 {
352 	struct drm_framebuffer *fb = plane_state->fb;
353 	struct drm_rect rect = {
354 		.x1 = 0,
355 		.x2 = fb->width,
356 		.y1 = 0,
357 		.y2 = fb->height,
358 	};
359 	int idx;
360 
361 	if (!drm_dev_enter(&dbidev->drm, &idx))
362 		return;
363 
364 	mipi_dbi_fb_dirty(fb, &rect);
365 	backlight_enable(dbidev->backlight);
366 
367 	drm_dev_exit(idx);
368 }
369 EXPORT_SYMBOL(mipi_dbi_enable_flush);
370 
371 static void mipi_dbi_blank(struct mipi_dbi_dev *dbidev)
372 {
373 	struct drm_device *drm = &dbidev->drm;
374 	u16 height = drm->mode_config.min_height;
375 	u16 width = drm->mode_config.min_width;
376 	struct mipi_dbi *dbi = &dbidev->dbi;
377 	size_t len = width * height * 2;
378 	int idx;
379 
380 	if (!drm_dev_enter(drm, &idx))
381 		return;
382 
383 	memset(dbidev->tx_buf, 0, len);
384 
385 	mipi_dbi_set_window_address(dbidev, 0, width - 1, 0, height - 1);
386 	mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START,
387 			     (u8 *)dbidev->tx_buf, len);
388 
389 	drm_dev_exit(idx);
390 }
391 
392 /**
393  * mipi_dbi_pipe_disable - MIPI DBI pipe disable helper
394  * @pipe: Display pipe
395  *
396  * This function disables backlight if present, if not the display memory is
397  * blanked. The regulator is disabled if in use. Drivers can use this as their
398  * &drm_simple_display_pipe_funcs->disable callback.
399  */
400 void mipi_dbi_pipe_disable(struct drm_simple_display_pipe *pipe)
401 {
402 	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
403 
404 	DRM_DEBUG_KMS("\n");
405 
406 	if (dbidev->backlight)
407 		backlight_disable(dbidev->backlight);
408 	else
409 		mipi_dbi_blank(dbidev);
410 
411 	if (dbidev->regulator)
412 		regulator_disable(dbidev->regulator);
413 }
414 EXPORT_SYMBOL(mipi_dbi_pipe_disable);
415 
416 static int mipi_dbi_connector_get_modes(struct drm_connector *connector)
417 {
418 	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(connector->dev);
419 	struct drm_display_mode *mode;
420 
421 	mode = drm_mode_duplicate(connector->dev, &dbidev->mode);
422 	if (!mode) {
423 		DRM_ERROR("Failed to duplicate mode\n");
424 		return 0;
425 	}
426 
427 	if (mode->name[0] == '\0')
428 		drm_mode_set_name(mode);
429 
430 	mode->type |= DRM_MODE_TYPE_PREFERRED;
431 	drm_mode_probed_add(connector, mode);
432 
433 	if (mode->width_mm) {
434 		connector->display_info.width_mm = mode->width_mm;
435 		connector->display_info.height_mm = mode->height_mm;
436 	}
437 
438 	return 1;
439 }
440 
441 static const struct drm_connector_helper_funcs mipi_dbi_connector_hfuncs = {
442 	.get_modes = mipi_dbi_connector_get_modes,
443 };
444 
445 static const struct drm_connector_funcs mipi_dbi_connector_funcs = {
446 	.reset = drm_atomic_helper_connector_reset,
447 	.fill_modes = drm_helper_probe_single_connector_modes,
448 	.destroy = drm_connector_cleanup,
449 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
450 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
451 };
452 
453 static int mipi_dbi_rotate_mode(struct drm_display_mode *mode,
454 				unsigned int rotation)
455 {
456 	if (rotation == 0 || rotation == 180) {
457 		return 0;
458 	} else if (rotation == 90 || rotation == 270) {
459 		swap(mode->hdisplay, mode->vdisplay);
460 		swap(mode->hsync_start, mode->vsync_start);
461 		swap(mode->hsync_end, mode->vsync_end);
462 		swap(mode->htotal, mode->vtotal);
463 		swap(mode->width_mm, mode->height_mm);
464 		return 0;
465 	} else {
466 		return -EINVAL;
467 	}
468 }
469 
470 static const struct drm_mode_config_funcs mipi_dbi_mode_config_funcs = {
471 	.fb_create = drm_gem_fb_create_with_dirty,
472 	.atomic_check = drm_atomic_helper_check,
473 	.atomic_commit = drm_atomic_helper_commit,
474 };
475 
476 static const uint32_t mipi_dbi_formats[] = {
477 	DRM_FORMAT_RGB565,
478 	DRM_FORMAT_XRGB8888,
479 };
480 
481 /**
482  * mipi_dbi_dev_init_with_formats - MIPI DBI device initialization with custom formats
483  * @dbidev: MIPI DBI device structure to initialize
484  * @funcs: Display pipe functions
485  * @formats: Array of supported formats (DRM_FORMAT\_\*).
486  * @format_count: Number of elements in @formats
487  * @mode: Display mode
488  * @rotation: Initial rotation in degrees Counter Clock Wise
489  * @tx_buf_size: Allocate a transmit buffer of this size.
490  *
491  * This function sets up a &drm_simple_display_pipe with a &drm_connector that
492  * has one fixed &drm_display_mode which is rotated according to @rotation.
493  * This mode is used to set the mode config min/max width/height properties.
494  *
495  * Use mipi_dbi_dev_init() if you don't need custom formats.
496  *
497  * Note:
498  * Some of the helper functions expects RGB565 to be the default format and the
499  * transmit buffer sized to fit that.
500  *
501  * Returns:
502  * Zero on success, negative error code on failure.
503  */
504 int mipi_dbi_dev_init_with_formats(struct mipi_dbi_dev *dbidev,
505 				   const struct drm_simple_display_pipe_funcs *funcs,
506 				   const uint32_t *formats, unsigned int format_count,
507 				   const struct drm_display_mode *mode,
508 				   unsigned int rotation, size_t tx_buf_size)
509 {
510 	static const uint64_t modifiers[] = {
511 		DRM_FORMAT_MOD_LINEAR,
512 		DRM_FORMAT_MOD_INVALID
513 	};
514 	struct drm_device *drm = &dbidev->drm;
515 	int ret;
516 
517 	if (!dbidev->dbi.command)
518 		return -EINVAL;
519 
520 	ret = drmm_mode_config_init(drm);
521 	if (ret)
522 		return ret;
523 
524 	dbidev->tx_buf = devm_kmalloc(drm->dev, tx_buf_size, GFP_KERNEL);
525 	if (!dbidev->tx_buf)
526 		return -ENOMEM;
527 
528 	drm_mode_copy(&dbidev->mode, mode);
529 	ret = mipi_dbi_rotate_mode(&dbidev->mode, rotation);
530 	if (ret) {
531 		DRM_ERROR("Illegal rotation value %u\n", rotation);
532 		return -EINVAL;
533 	}
534 
535 	drm_connector_helper_add(&dbidev->connector, &mipi_dbi_connector_hfuncs);
536 	ret = drm_connector_init(drm, &dbidev->connector, &mipi_dbi_connector_funcs,
537 				 DRM_MODE_CONNECTOR_SPI);
538 	if (ret)
539 		return ret;
540 
541 	ret = drm_simple_display_pipe_init(drm, &dbidev->pipe, funcs, formats, format_count,
542 					   modifiers, &dbidev->connector);
543 	if (ret)
544 		return ret;
545 
546 	drm_plane_enable_fb_damage_clips(&dbidev->pipe.plane);
547 
548 	drm->mode_config.funcs = &mipi_dbi_mode_config_funcs;
549 	drm->mode_config.min_width = dbidev->mode.hdisplay;
550 	drm->mode_config.max_width = dbidev->mode.hdisplay;
551 	drm->mode_config.min_height = dbidev->mode.vdisplay;
552 	drm->mode_config.max_height = dbidev->mode.vdisplay;
553 	dbidev->rotation = rotation;
554 
555 	DRM_DEBUG_KMS("rotation = %u\n", rotation);
556 
557 	return 0;
558 }
559 EXPORT_SYMBOL(mipi_dbi_dev_init_with_formats);
560 
561 /**
562  * mipi_dbi_dev_init - MIPI DBI device initialization
563  * @dbidev: MIPI DBI device structure to initialize
564  * @funcs: Display pipe functions
565  * @mode: Display mode
566  * @rotation: Initial rotation in degrees Counter Clock Wise
567  *
568  * This function sets up a &drm_simple_display_pipe with a &drm_connector that
569  * has one fixed &drm_display_mode which is rotated according to @rotation.
570  * This mode is used to set the mode config min/max width/height properties.
571  * Additionally &mipi_dbi.tx_buf is allocated.
572  *
573  * Supported formats: Native RGB565 and emulated XRGB8888.
574  *
575  * Returns:
576  * Zero on success, negative error code on failure.
577  */
578 int mipi_dbi_dev_init(struct mipi_dbi_dev *dbidev,
579 		      const struct drm_simple_display_pipe_funcs *funcs,
580 		      const struct drm_display_mode *mode, unsigned int rotation)
581 {
582 	size_t bufsize = mode->vdisplay * mode->hdisplay * sizeof(u16);
583 
584 	dbidev->drm.mode_config.preferred_depth = 16;
585 
586 	return mipi_dbi_dev_init_with_formats(dbidev, funcs, mipi_dbi_formats,
587 					      ARRAY_SIZE(mipi_dbi_formats), mode,
588 					      rotation, bufsize);
589 }
590 EXPORT_SYMBOL(mipi_dbi_dev_init);
591 
592 /**
593  * mipi_dbi_hw_reset - Hardware reset of controller
594  * @dbi: MIPI DBI structure
595  *
596  * Reset controller if the &mipi_dbi->reset gpio is set.
597  */
598 void mipi_dbi_hw_reset(struct mipi_dbi *dbi)
599 {
600 	if (!dbi->reset)
601 		return;
602 
603 	gpiod_set_value_cansleep(dbi->reset, 0);
604 	usleep_range(20, 1000);
605 	gpiod_set_value_cansleep(dbi->reset, 1);
606 	msleep(120);
607 }
608 EXPORT_SYMBOL(mipi_dbi_hw_reset);
609 
610 /**
611  * mipi_dbi_display_is_on - Check if display is on
612  * @dbi: MIPI DBI structure
613  *
614  * This function checks the Power Mode register (if readable) to see if
615  * display output is turned on. This can be used to see if the bootloader
616  * has already turned on the display avoiding flicker when the pipeline is
617  * enabled.
618  *
619  * Returns:
620  * true if the display can be verified to be on, false otherwise.
621  */
622 bool mipi_dbi_display_is_on(struct mipi_dbi *dbi)
623 {
624 	u8 val;
625 
626 	if (mipi_dbi_command_read(dbi, MIPI_DCS_GET_POWER_MODE, &val))
627 		return false;
628 
629 	val &= ~DCS_POWER_MODE_RESERVED_MASK;
630 
631 	/* The poweron/reset value is 08h DCS_POWER_MODE_DISPLAY_NORMAL_MODE */
632 	if (val != (DCS_POWER_MODE_DISPLAY |
633 	    DCS_POWER_MODE_DISPLAY_NORMAL_MODE | DCS_POWER_MODE_SLEEP_MODE))
634 		return false;
635 
636 	DRM_DEBUG_DRIVER("Display is ON\n");
637 
638 	return true;
639 }
640 EXPORT_SYMBOL(mipi_dbi_display_is_on);
641 
642 static int mipi_dbi_poweron_reset_conditional(struct mipi_dbi_dev *dbidev, bool cond)
643 {
644 	struct device *dev = dbidev->drm.dev;
645 	struct mipi_dbi *dbi = &dbidev->dbi;
646 	int ret;
647 
648 	if (dbidev->regulator) {
649 		ret = regulator_enable(dbidev->regulator);
650 		if (ret) {
651 			DRM_DEV_ERROR(dev, "Failed to enable regulator (%d)\n", ret);
652 			return ret;
653 		}
654 	}
655 
656 	if (cond && mipi_dbi_display_is_on(dbi))
657 		return 1;
658 
659 	mipi_dbi_hw_reset(dbi);
660 	ret = mipi_dbi_command(dbi, MIPI_DCS_SOFT_RESET);
661 	if (ret) {
662 		DRM_DEV_ERROR(dev, "Failed to send reset command (%d)\n", ret);
663 		if (dbidev->regulator)
664 			regulator_disable(dbidev->regulator);
665 		return ret;
666 	}
667 
668 	/*
669 	 * If we did a hw reset, we know the controller is in Sleep mode and
670 	 * per MIPI DSC spec should wait 5ms after soft reset. If we didn't,
671 	 * we assume worst case and wait 120ms.
672 	 */
673 	if (dbi->reset)
674 		usleep_range(5000, 20000);
675 	else
676 		msleep(120);
677 
678 	return 0;
679 }
680 
681 /**
682  * mipi_dbi_poweron_reset - MIPI DBI poweron and reset
683  * @dbidev: MIPI DBI device structure
684  *
685  * This function enables the regulator if used and does a hardware and software
686  * reset.
687  *
688  * Returns:
689  * Zero on success, or a negative error code.
690  */
691 int mipi_dbi_poweron_reset(struct mipi_dbi_dev *dbidev)
692 {
693 	return mipi_dbi_poweron_reset_conditional(dbidev, false);
694 }
695 EXPORT_SYMBOL(mipi_dbi_poweron_reset);
696 
697 /**
698  * mipi_dbi_poweron_conditional_reset - MIPI DBI poweron and conditional reset
699  * @dbidev: MIPI DBI device structure
700  *
701  * This function enables the regulator if used and if the display is off, it
702  * does a hardware and software reset. If mipi_dbi_display_is_on() determines
703  * that the display is on, no reset is performed.
704  *
705  * Returns:
706  * Zero if the controller was reset, 1 if the display was already on, or a
707  * negative error code.
708  */
709 int mipi_dbi_poweron_conditional_reset(struct mipi_dbi_dev *dbidev)
710 {
711 	return mipi_dbi_poweron_reset_conditional(dbidev, true);
712 }
713 EXPORT_SYMBOL(mipi_dbi_poweron_conditional_reset);
714 
715 #if IS_ENABLED(CONFIG_SPI)
716 
717 /**
718  * mipi_dbi_spi_cmd_max_speed - get the maximum SPI bus speed
719  * @spi: SPI device
720  * @len: The transfer buffer length.
721  *
722  * Many controllers have a max speed of 10MHz, but can be pushed way beyond
723  * that. Increase reliability by running pixel data at max speed and the rest
724  * at 10MHz, preventing transfer glitches from messing up the init settings.
725  */
726 u32 mipi_dbi_spi_cmd_max_speed(struct spi_device *spi, size_t len)
727 {
728 	if (len > 64)
729 		return 0; /* use default */
730 
731 	return min_t(u32, 10000000, spi->max_speed_hz);
732 }
733 EXPORT_SYMBOL(mipi_dbi_spi_cmd_max_speed);
734 
735 static bool mipi_dbi_machine_little_endian(void)
736 {
737 #if defined(__LITTLE_ENDIAN)
738 	return true;
739 #else
740 	return false;
741 #endif
742 }
743 
744 /*
745  * MIPI DBI Type C Option 1
746  *
747  * If the SPI controller doesn't have 9 bits per word support,
748  * use blocks of 9 bytes to send 8x 9-bit words using a 8-bit SPI transfer.
749  * Pad partial blocks with MIPI_DCS_NOP (zero).
750  * This is how the D/C bit (x) is added:
751  *     x7654321
752  *     0x765432
753  *     10x76543
754  *     210x7654
755  *     3210x765
756  *     43210x76
757  *     543210x7
758  *     6543210x
759  *     76543210
760  */
761 
762 static int mipi_dbi_spi1e_transfer(struct mipi_dbi *dbi, int dc,
763 				   const void *buf, size_t len,
764 				   unsigned int bpw)
765 {
766 	bool swap_bytes = (bpw == 16 && mipi_dbi_machine_little_endian());
767 	size_t chunk, max_chunk = dbi->tx_buf9_len;
768 	struct spi_device *spi = dbi->spi;
769 	struct spi_transfer tr = {
770 		.tx_buf = dbi->tx_buf9,
771 		.bits_per_word = 8,
772 	};
773 	struct spi_message m;
774 	const u8 *src = buf;
775 	int i, ret;
776 	u8 *dst;
777 
778 	if (drm_debug_enabled(DRM_UT_DRIVER))
779 		pr_debug("[drm:%s] dc=%d, max_chunk=%zu, transfers:\n",
780 			 __func__, dc, max_chunk);
781 
782 	tr.speed_hz = mipi_dbi_spi_cmd_max_speed(spi, len);
783 	spi_message_init_with_transfers(&m, &tr, 1);
784 
785 	if (!dc) {
786 		if (WARN_ON_ONCE(len != 1))
787 			return -EINVAL;
788 
789 		/* Command: pad no-op's (zeroes) at beginning of block */
790 		dst = dbi->tx_buf9;
791 		memset(dst, 0, 9);
792 		dst[8] = *src;
793 		tr.len = 9;
794 
795 		return spi_sync(spi, &m);
796 	}
797 
798 	/* max with room for adding one bit per byte */
799 	max_chunk = max_chunk / 9 * 8;
800 	/* but no bigger than len */
801 	max_chunk = min(max_chunk, len);
802 	/* 8 byte blocks */
803 	max_chunk = max_t(size_t, 8, max_chunk & ~0x7);
804 
805 	while (len) {
806 		size_t added = 0;
807 
808 		chunk = min(len, max_chunk);
809 		len -= chunk;
810 		dst = dbi->tx_buf9;
811 
812 		if (chunk < 8) {
813 			u8 val, carry = 0;
814 
815 			/* Data: pad no-op's (zeroes) at end of block */
816 			memset(dst, 0, 9);
817 
818 			if (swap_bytes) {
819 				for (i = 1; i < (chunk + 1); i++) {
820 					val = src[1];
821 					*dst++ = carry | BIT(8 - i) | (val >> i);
822 					carry = val << (8 - i);
823 					i++;
824 					val = src[0];
825 					*dst++ = carry | BIT(8 - i) | (val >> i);
826 					carry = val << (8 - i);
827 					src += 2;
828 				}
829 				*dst++ = carry;
830 			} else {
831 				for (i = 1; i < (chunk + 1); i++) {
832 					val = *src++;
833 					*dst++ = carry | BIT(8 - i) | (val >> i);
834 					carry = val << (8 - i);
835 				}
836 				*dst++ = carry;
837 			}
838 
839 			chunk = 8;
840 			added = 1;
841 		} else {
842 			for (i = 0; i < chunk; i += 8) {
843 				if (swap_bytes) {
844 					*dst++ =                 BIT(7) | (src[1] >> 1);
845 					*dst++ = (src[1] << 7) | BIT(6) | (src[0] >> 2);
846 					*dst++ = (src[0] << 6) | BIT(5) | (src[3] >> 3);
847 					*dst++ = (src[3] << 5) | BIT(4) | (src[2] >> 4);
848 					*dst++ = (src[2] << 4) | BIT(3) | (src[5] >> 5);
849 					*dst++ = (src[5] << 3) | BIT(2) | (src[4] >> 6);
850 					*dst++ = (src[4] << 2) | BIT(1) | (src[7] >> 7);
851 					*dst++ = (src[7] << 1) | BIT(0);
852 					*dst++ = src[6];
853 				} else {
854 					*dst++ =                 BIT(7) | (src[0] >> 1);
855 					*dst++ = (src[0] << 7) | BIT(6) | (src[1] >> 2);
856 					*dst++ = (src[1] << 6) | BIT(5) | (src[2] >> 3);
857 					*dst++ = (src[2] << 5) | BIT(4) | (src[3] >> 4);
858 					*dst++ = (src[3] << 4) | BIT(3) | (src[4] >> 5);
859 					*dst++ = (src[4] << 3) | BIT(2) | (src[5] >> 6);
860 					*dst++ = (src[5] << 2) | BIT(1) | (src[6] >> 7);
861 					*dst++ = (src[6] << 1) | BIT(0);
862 					*dst++ = src[7];
863 				}
864 
865 				src += 8;
866 				added++;
867 			}
868 		}
869 
870 		tr.len = chunk + added;
871 
872 		ret = spi_sync(spi, &m);
873 		if (ret)
874 			return ret;
875 	}
876 
877 	return 0;
878 }
879 
880 static int mipi_dbi_spi1_transfer(struct mipi_dbi *dbi, int dc,
881 				  const void *buf, size_t len,
882 				  unsigned int bpw)
883 {
884 	struct spi_device *spi = dbi->spi;
885 	struct spi_transfer tr = {
886 		.bits_per_word = 9,
887 	};
888 	const u16 *src16 = buf;
889 	const u8 *src8 = buf;
890 	struct spi_message m;
891 	size_t max_chunk;
892 	u16 *dst16;
893 	int ret;
894 
895 	if (!spi_is_bpw_supported(spi, 9))
896 		return mipi_dbi_spi1e_transfer(dbi, dc, buf, len, bpw);
897 
898 	tr.speed_hz = mipi_dbi_spi_cmd_max_speed(spi, len);
899 	max_chunk = dbi->tx_buf9_len;
900 	dst16 = dbi->tx_buf9;
901 
902 	if (drm_debug_enabled(DRM_UT_DRIVER))
903 		pr_debug("[drm:%s] dc=%d, max_chunk=%zu, transfers:\n",
904 			 __func__, dc, max_chunk);
905 
906 	max_chunk = min(max_chunk / 2, len);
907 
908 	spi_message_init_with_transfers(&m, &tr, 1);
909 	tr.tx_buf = dst16;
910 
911 	while (len) {
912 		size_t chunk = min(len, max_chunk);
913 		unsigned int i;
914 
915 		if (bpw == 16 && mipi_dbi_machine_little_endian()) {
916 			for (i = 0; i < (chunk * 2); i += 2) {
917 				dst16[i]     = *src16 >> 8;
918 				dst16[i + 1] = *src16++ & 0xFF;
919 				if (dc) {
920 					dst16[i]     |= 0x0100;
921 					dst16[i + 1] |= 0x0100;
922 				}
923 			}
924 		} else {
925 			for (i = 0; i < chunk; i++) {
926 				dst16[i] = *src8++;
927 				if (dc)
928 					dst16[i] |= 0x0100;
929 			}
930 		}
931 
932 		tr.len = chunk * 2;
933 		len -= chunk;
934 
935 		ret = spi_sync(spi, &m);
936 		if (ret)
937 			return ret;
938 	}
939 
940 	return 0;
941 }
942 
943 static int mipi_dbi_typec1_command_read(struct mipi_dbi *dbi, u8 *cmd,
944 					u8 *data, size_t len)
945 {
946 	struct spi_device *spi = dbi->spi;
947 	u32 speed_hz = min_t(u32, MIPI_DBI_MAX_SPI_READ_SPEED,
948 			     spi->max_speed_hz / 2);
949 	struct spi_transfer tr[2] = {
950 		{
951 			.speed_hz = speed_hz,
952 			.bits_per_word = 9,
953 			.tx_buf = dbi->tx_buf9,
954 			.len = 2,
955 		}, {
956 			.speed_hz = speed_hz,
957 			.bits_per_word = 8,
958 			.len = len,
959 			.rx_buf = data,
960 		},
961 	};
962 	struct spi_message m;
963 	u16 *dst16;
964 	int ret;
965 
966 	if (!len)
967 		return -EINVAL;
968 
969 	if (!spi_is_bpw_supported(spi, 9)) {
970 		/*
971 		 * FIXME: implement something like mipi_dbi_spi1e_transfer() but
972 		 * for reads using emulation.
973 		 */
974 		dev_err(&spi->dev,
975 			"reading on host not supporting 9 bpw not yet implemented\n");
976 		return -EOPNOTSUPP;
977 	}
978 
979 	/*
980 	 * Turn the 8bit command into a 16bit version of the command in the
981 	 * buffer. Only 9 bits of this will be used when executing the actual
982 	 * transfer.
983 	 */
984 	dst16 = dbi->tx_buf9;
985 	dst16[0] = *cmd;
986 
987 	spi_message_init_with_transfers(&m, tr, ARRAY_SIZE(tr));
988 	ret = spi_sync(spi, &m);
989 
990 	if (!ret)
991 		MIPI_DBI_DEBUG_COMMAND(*cmd, data, len);
992 
993 	return ret;
994 }
995 
996 static int mipi_dbi_typec1_command(struct mipi_dbi *dbi, u8 *cmd,
997 				   u8 *parameters, size_t num)
998 {
999 	unsigned int bpw = (*cmd == MIPI_DCS_WRITE_MEMORY_START) ? 16 : 8;
1000 	int ret;
1001 
1002 	if (mipi_dbi_command_is_read(dbi, *cmd))
1003 		return mipi_dbi_typec1_command_read(dbi, cmd, parameters, num);
1004 
1005 	MIPI_DBI_DEBUG_COMMAND(*cmd, parameters, num);
1006 
1007 	ret = mipi_dbi_spi1_transfer(dbi, 0, cmd, 1, 8);
1008 	if (ret || !num)
1009 		return ret;
1010 
1011 	return mipi_dbi_spi1_transfer(dbi, 1, parameters, num, bpw);
1012 }
1013 
1014 /* MIPI DBI Type C Option 3 */
1015 
1016 static int mipi_dbi_typec3_command_read(struct mipi_dbi *dbi, u8 *cmd,
1017 					u8 *data, size_t len)
1018 {
1019 	struct spi_device *spi = dbi->spi;
1020 	u32 speed_hz = min_t(u32, MIPI_DBI_MAX_SPI_READ_SPEED,
1021 			     spi->max_speed_hz / 2);
1022 	struct spi_transfer tr[2] = {
1023 		{
1024 			.speed_hz = speed_hz,
1025 			.tx_buf = cmd,
1026 			.len = 1,
1027 		}, {
1028 			.speed_hz = speed_hz,
1029 			.len = len,
1030 		},
1031 	};
1032 	struct spi_message m;
1033 	u8 *buf;
1034 	int ret;
1035 
1036 	if (!len)
1037 		return -EINVAL;
1038 
1039 	/*
1040 	 * Support non-standard 24-bit and 32-bit Nokia read commands which
1041 	 * start with a dummy clock, so we need to read an extra byte.
1042 	 */
1043 	if (*cmd == MIPI_DCS_GET_DISPLAY_ID ||
1044 	    *cmd == MIPI_DCS_GET_DISPLAY_STATUS) {
1045 		if (!(len == 3 || len == 4))
1046 			return -EINVAL;
1047 
1048 		tr[1].len = len + 1;
1049 	}
1050 
1051 	buf = kmalloc(tr[1].len, GFP_KERNEL);
1052 	if (!buf)
1053 		return -ENOMEM;
1054 
1055 	tr[1].rx_buf = buf;
1056 	gpiod_set_value_cansleep(dbi->dc, 0);
1057 
1058 	spi_message_init_with_transfers(&m, tr, ARRAY_SIZE(tr));
1059 	ret = spi_sync(spi, &m);
1060 	if (ret)
1061 		goto err_free;
1062 
1063 	if (tr[1].len == len) {
1064 		memcpy(data, buf, len);
1065 	} else {
1066 		unsigned int i;
1067 
1068 		for (i = 0; i < len; i++)
1069 			data[i] = (buf[i] << 1) | (buf[i + 1] >> 7);
1070 	}
1071 
1072 	MIPI_DBI_DEBUG_COMMAND(*cmd, data, len);
1073 
1074 err_free:
1075 	kfree(buf);
1076 
1077 	return ret;
1078 }
1079 
1080 static int mipi_dbi_typec3_command(struct mipi_dbi *dbi, u8 *cmd,
1081 				   u8 *par, size_t num)
1082 {
1083 	struct spi_device *spi = dbi->spi;
1084 	unsigned int bpw = 8;
1085 	u32 speed_hz;
1086 	int ret;
1087 
1088 	if (mipi_dbi_command_is_read(dbi, *cmd))
1089 		return mipi_dbi_typec3_command_read(dbi, cmd, par, num);
1090 
1091 	MIPI_DBI_DEBUG_COMMAND(*cmd, par, num);
1092 
1093 	gpiod_set_value_cansleep(dbi->dc, 0);
1094 	speed_hz = mipi_dbi_spi_cmd_max_speed(spi, 1);
1095 	ret = mipi_dbi_spi_transfer(spi, speed_hz, 8, cmd, 1);
1096 	if (ret || !num)
1097 		return ret;
1098 
1099 	if (*cmd == MIPI_DCS_WRITE_MEMORY_START && !dbi->swap_bytes)
1100 		bpw = 16;
1101 
1102 	gpiod_set_value_cansleep(dbi->dc, 1);
1103 	speed_hz = mipi_dbi_spi_cmd_max_speed(spi, num);
1104 
1105 	return mipi_dbi_spi_transfer(spi, speed_hz, bpw, par, num);
1106 }
1107 
1108 /**
1109  * mipi_dbi_spi_init - Initialize MIPI DBI SPI interface
1110  * @spi: SPI device
1111  * @dbi: MIPI DBI structure to initialize
1112  * @dc: D/C gpio (optional)
1113  *
1114  * This function sets &mipi_dbi->command, enables &mipi_dbi->read_commands for the
1115  * usual read commands. It should be followed by a call to mipi_dbi_dev_init() or
1116  * a driver-specific init.
1117  *
1118  * If @dc is set, a Type C Option 3 interface is assumed, if not
1119  * Type C Option 1.
1120  *
1121  * If the SPI master driver doesn't support the necessary bits per word,
1122  * the following transformation is used:
1123  *
1124  * - 9-bit: reorder buffer as 9x 8-bit words, padded with no-op command.
1125  * - 16-bit: if big endian send as 8-bit, if little endian swap bytes
1126  *
1127  * Returns:
1128  * Zero on success, negative error code on failure.
1129  */
1130 int mipi_dbi_spi_init(struct spi_device *spi, struct mipi_dbi *dbi,
1131 		      struct gpio_desc *dc)
1132 {
1133 	struct device *dev = &spi->dev;
1134 	int ret;
1135 
1136 	/*
1137 	 * Even though it's not the SPI device that does DMA (the master does),
1138 	 * the dma mask is necessary for the dma_alloc_wc() in the GEM code
1139 	 * (e.g., drm_gem_cma_create()). The dma_addr returned will be a physical
1140 	 * address which might be different from the bus address, but this is
1141 	 * not a problem since the address will not be used.
1142 	 * The virtual address is used in the transfer and the SPI core
1143 	 * re-maps it on the SPI master device using the DMA streaming API
1144 	 * (spi_map_buf()).
1145 	 */
1146 	if (!dev->coherent_dma_mask) {
1147 		ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
1148 		if (ret) {
1149 			dev_warn(dev, "Failed to set dma mask %d\n", ret);
1150 			return ret;
1151 		}
1152 	}
1153 
1154 	dbi->spi = spi;
1155 	dbi->read_commands = mipi_dbi_dcs_read_commands;
1156 
1157 	if (dc) {
1158 		dbi->command = mipi_dbi_typec3_command;
1159 		dbi->dc = dc;
1160 		if (mipi_dbi_machine_little_endian() && !spi_is_bpw_supported(spi, 16))
1161 			dbi->swap_bytes = true;
1162 	} else {
1163 		dbi->command = mipi_dbi_typec1_command;
1164 		dbi->tx_buf9_len = SZ_16K;
1165 		dbi->tx_buf9 = devm_kmalloc(dev, dbi->tx_buf9_len, GFP_KERNEL);
1166 		if (!dbi->tx_buf9)
1167 			return -ENOMEM;
1168 	}
1169 
1170 	mutex_init(&dbi->cmdlock);
1171 
1172 	DRM_DEBUG_DRIVER("SPI speed: %uMHz\n", spi->max_speed_hz / 1000000);
1173 
1174 	return 0;
1175 }
1176 EXPORT_SYMBOL(mipi_dbi_spi_init);
1177 
1178 /**
1179  * mipi_dbi_spi_transfer - SPI transfer helper
1180  * @spi: SPI device
1181  * @speed_hz: Override speed (optional)
1182  * @bpw: Bits per word
1183  * @buf: Buffer to transfer
1184  * @len: Buffer length
1185  *
1186  * This SPI transfer helper breaks up the transfer of @buf into chunks which
1187  * the SPI controller driver can handle.
1188  *
1189  * Returns:
1190  * Zero on success, negative error code on failure.
1191  */
1192 int mipi_dbi_spi_transfer(struct spi_device *spi, u32 speed_hz,
1193 			  u8 bpw, const void *buf, size_t len)
1194 {
1195 	size_t max_chunk = spi_max_transfer_size(spi);
1196 	struct spi_transfer tr = {
1197 		.bits_per_word = bpw,
1198 		.speed_hz = speed_hz,
1199 	};
1200 	struct spi_message m;
1201 	size_t chunk;
1202 	int ret;
1203 
1204 	/* In __spi_validate, there's a validation that no partial transfers
1205 	 * are accepted (xfer->len % w_size must be zero).
1206 	 * Here we align max_chunk to multiple of 2 (16bits),
1207 	 * to prevent transfers from being rejected.
1208 	 */
1209 	max_chunk = ALIGN_DOWN(max_chunk, 2);
1210 
1211 	spi_message_init_with_transfers(&m, &tr, 1);
1212 
1213 	while (len) {
1214 		chunk = min(len, max_chunk);
1215 
1216 		tr.tx_buf = buf;
1217 		tr.len = chunk;
1218 		buf += chunk;
1219 		len -= chunk;
1220 
1221 		ret = spi_sync(spi, &m);
1222 		if (ret)
1223 			return ret;
1224 	}
1225 
1226 	return 0;
1227 }
1228 EXPORT_SYMBOL(mipi_dbi_spi_transfer);
1229 
1230 #endif /* CONFIG_SPI */
1231 
1232 #ifdef CONFIG_DEBUG_FS
1233 
1234 static ssize_t mipi_dbi_debugfs_command_write(struct file *file,
1235 					      const char __user *ubuf,
1236 					      size_t count, loff_t *ppos)
1237 {
1238 	struct seq_file *m = file->private_data;
1239 	struct mipi_dbi_dev *dbidev = m->private;
1240 	u8 val, cmd = 0, parameters[64];
1241 	char *buf, *pos, *token;
1242 	int i, ret, idx;
1243 
1244 	if (!drm_dev_enter(&dbidev->drm, &idx))
1245 		return -ENODEV;
1246 
1247 	buf = memdup_user_nul(ubuf, count);
1248 	if (IS_ERR(buf)) {
1249 		ret = PTR_ERR(buf);
1250 		goto err_exit;
1251 	}
1252 
1253 	/* strip trailing whitespace */
1254 	for (i = count - 1; i > 0; i--)
1255 		if (isspace(buf[i]))
1256 			buf[i] = '\0';
1257 		else
1258 			break;
1259 	i = 0;
1260 	pos = buf;
1261 	while (pos) {
1262 		token = strsep(&pos, " ");
1263 		if (!token) {
1264 			ret = -EINVAL;
1265 			goto err_free;
1266 		}
1267 
1268 		ret = kstrtou8(token, 16, &val);
1269 		if (ret < 0)
1270 			goto err_free;
1271 
1272 		if (token == buf)
1273 			cmd = val;
1274 		else
1275 			parameters[i++] = val;
1276 
1277 		if (i == 64) {
1278 			ret = -E2BIG;
1279 			goto err_free;
1280 		}
1281 	}
1282 
1283 	ret = mipi_dbi_command_buf(&dbidev->dbi, cmd, parameters, i);
1284 
1285 err_free:
1286 	kfree(buf);
1287 err_exit:
1288 	drm_dev_exit(idx);
1289 
1290 	return ret < 0 ? ret : count;
1291 }
1292 
1293 static int mipi_dbi_debugfs_command_show(struct seq_file *m, void *unused)
1294 {
1295 	struct mipi_dbi_dev *dbidev = m->private;
1296 	struct mipi_dbi *dbi = &dbidev->dbi;
1297 	u8 cmd, val[4];
1298 	int ret, idx;
1299 	size_t len;
1300 
1301 	if (!drm_dev_enter(&dbidev->drm, &idx))
1302 		return -ENODEV;
1303 
1304 	for (cmd = 0; cmd < 255; cmd++) {
1305 		if (!mipi_dbi_command_is_read(dbi, cmd))
1306 			continue;
1307 
1308 		switch (cmd) {
1309 		case MIPI_DCS_READ_MEMORY_START:
1310 		case MIPI_DCS_READ_MEMORY_CONTINUE:
1311 			len = 2;
1312 			break;
1313 		case MIPI_DCS_GET_DISPLAY_ID:
1314 			len = 3;
1315 			break;
1316 		case MIPI_DCS_GET_DISPLAY_STATUS:
1317 			len = 4;
1318 			break;
1319 		default:
1320 			len = 1;
1321 			break;
1322 		}
1323 
1324 		seq_printf(m, "%02x: ", cmd);
1325 		ret = mipi_dbi_command_buf(dbi, cmd, val, len);
1326 		if (ret) {
1327 			seq_puts(m, "XX\n");
1328 			continue;
1329 		}
1330 		seq_printf(m, "%*phN\n", (int)len, val);
1331 	}
1332 
1333 	drm_dev_exit(idx);
1334 
1335 	return 0;
1336 }
1337 
1338 static int mipi_dbi_debugfs_command_open(struct inode *inode,
1339 					 struct file *file)
1340 {
1341 	return single_open(file, mipi_dbi_debugfs_command_show,
1342 			   inode->i_private);
1343 }
1344 
1345 static const struct file_operations mipi_dbi_debugfs_command_fops = {
1346 	.owner = THIS_MODULE,
1347 	.open = mipi_dbi_debugfs_command_open,
1348 	.read = seq_read,
1349 	.llseek = seq_lseek,
1350 	.release = single_release,
1351 	.write = mipi_dbi_debugfs_command_write,
1352 };
1353 
1354 /**
1355  * mipi_dbi_debugfs_init - Create debugfs entries
1356  * @minor: DRM minor
1357  *
1358  * This function creates a 'command' debugfs file for sending commands to the
1359  * controller or getting the read command values.
1360  * Drivers can use this as their &drm_driver->debugfs_init callback.
1361  *
1362  */
1363 void mipi_dbi_debugfs_init(struct drm_minor *minor)
1364 {
1365 	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(minor->dev);
1366 	umode_t mode = S_IFREG | S_IWUSR;
1367 
1368 	if (dbidev->dbi.read_commands)
1369 		mode |= S_IRUGO;
1370 	debugfs_create_file("command", mode, minor->debugfs_root, dbidev,
1371 			    &mipi_dbi_debugfs_command_fops);
1372 }
1373 EXPORT_SYMBOL(mipi_dbi_debugfs_init);
1374 
1375 #endif
1376 
1377 MODULE_LICENSE("GPL");
1378