xref: /linux/drivers/gpu/drm/sysfb/vesadrm.c (revision 814d270b31d27b6ea4f722b8ae2db9802fe332ff)
1 // SPDX-License-Identifier: GPL-2.0-only
2 
3 #include <linux/aperture.h>
4 #include <linux/ioport.h>
5 #include <linux/limits.h>
6 #include <linux/platform_device.h>
7 #include <linux/screen_info.h>
8 
9 #include <drm/clients/drm_client_setup.h>
10 #include <drm/drm_atomic.h>
11 #include <drm/drm_atomic_state_helper.h>
12 #include <drm/drm_connector.h>
13 #include <drm/drm_damage_helper.h>
14 #include <drm/drm_device.h>
15 #include <drm/drm_drv.h>
16 #include <drm/drm_edid.h>
17 #include <drm/drm_fbdev_shmem.h>
18 #include <drm/drm_framebuffer.h>
19 #include <drm/drm_gem_atomic_helper.h>
20 #include <drm/drm_gem_framebuffer_helper.h>
21 #include <drm/drm_gem_shmem_helper.h>
22 #include <drm/drm_managed.h>
23 #include <drm/drm_modeset_helper_vtables.h>
24 #include <drm/drm_probe_helper.h>
25 
26 #include <video/edid.h>
27 #include <video/pixel_format.h>
28 #include <video/vga.h>
29 
30 #include "drm_sysfb_helper.h"
31 
32 #define DRIVER_NAME	"vesadrm"
33 #define DRIVER_DESC	"DRM driver for VESA platform devices"
34 #define DRIVER_MAJOR	1
35 #define DRIVER_MINOR	0
36 
37 #define VESADRM_GAMMA_LUT_SIZE 256
38 
39 static int vesadrm_get_validated_int(struct drm_device *dev, const char *name,
40 				     u64 value, u32 max)
41 {
42 	if (max > INT_MAX)
43 		max = INT_MAX;
44 	if (value > max) {
45 		drm_err(dev, "%s of %llu exceeds maximum of %u\n", name, value, max);
46 		return -EINVAL;
47 	}
48 	return value;
49 }
50 
51 static int vesadrm_get_validated_int0(struct drm_device *dev, const char *name,
52 				      u64 value, u32 max)
53 {
54 	if (!value) {
55 		drm_err(dev, "%s of 0 not allowed\n", name);
56 		return -EINVAL;
57 	}
58 	return vesadrm_get_validated_int(dev, name, value, max);
59 }
60 
61 static s64 vesadrm_get_validated_size0(struct drm_device *dev, const char *name,
62 				       u64 value, u64 max)
63 {
64 	if (!value) {
65 		drm_err(dev, "vesadrm: %s of 0 not allowed\n", name);
66 		return -EINVAL;
67 	} else if (value > max) {
68 		drm_err(dev, "vesadrm: %s of %llu exceeds maximum of %llu\n", name, value, max);
69 		return -EINVAL;
70 	}
71 	return value;
72 }
73 
74 static int vesadrm_get_width_si(struct drm_device *dev, const struct screen_info *si)
75 {
76 	return vesadrm_get_validated_int0(dev, "width", si->lfb_width, U16_MAX);
77 }
78 
79 static int vesadrm_get_height_si(struct drm_device *dev, const struct screen_info *si)
80 {
81 	return vesadrm_get_validated_int0(dev, "height", si->lfb_height, U16_MAX);
82 }
83 
84 static struct resource *vesadrm_get_memory_si(struct drm_device *dev,
85 					      const struct screen_info *si,
86 					      struct resource *res)
87 {
88 	ssize_t	num;
89 
90 	num = screen_info_resources(si, res, 1);
91 	if (!num) {
92 		drm_err(dev, "vesadrm: memory resource not found\n");
93 		return NULL;
94 	}
95 
96 	return res;
97 }
98 
99 static int vesadrm_get_stride_si(struct drm_device *dev, const struct screen_info *si,
100 				 const struct drm_format_info *format,
101 				 unsigned int width, unsigned int height, u64 size)
102 {
103 	u64 lfb_linelength = si->lfb_linelength;
104 
105 	if (!lfb_linelength)
106 		lfb_linelength = drm_format_info_min_pitch(format, 0, width);
107 
108 	return vesadrm_get_validated_int0(dev, "stride", lfb_linelength, div64_u64(size, height));
109 }
110 
111 static u64 vesadrm_get_visible_size_si(struct drm_device *dev, const struct screen_info *si,
112 				       unsigned int height, unsigned int stride, u64 size)
113 {
114 	u64 vsize = PAGE_ALIGN(height * stride);
115 
116 	return vesadrm_get_validated_size0(dev, "visible size", vsize, size);
117 }
118 
119 static const struct drm_format_info *vesadrm_get_format_si(struct drm_device *dev,
120 							   const struct screen_info *si)
121 {
122 	static const struct {
123 		struct pixel_format pixel;
124 		u32 fourcc;
125 	} vesa_formats[] = {
126 		{ PIXEL_FORMAT_XRGB1555, DRM_FORMAT_XRGB1555, },
127 		{ PIXEL_FORMAT_RGB565, DRM_FORMAT_RGB565, },
128 		{ PIXEL_FORMAT_RGB888, DRM_FORMAT_RGB888, },
129 		{ PIXEL_FORMAT_XRGB8888, DRM_FORMAT_XRGB8888, },
130 		{ PIXEL_FORMAT_XBGR8888, DRM_FORMAT_XBGR8888, },
131 	};
132 	const struct drm_format_info *format = NULL;
133 	u32 bits_per_pixel;
134 	size_t i;
135 
136 	bits_per_pixel = __screen_info_lfb_bits_per_pixel(si);
137 
138 	for (i = 0; i < ARRAY_SIZE(vesa_formats); ++i) {
139 		const struct pixel_format *f = &vesa_formats[i].pixel;
140 
141 		if (bits_per_pixel == f->bits_per_pixel &&
142 		    si->red_size == f->red.length &&
143 		    si->red_pos == f->red.offset &&
144 		    si->green_size == f->green.length &&
145 		    si->green_pos == f->green.offset &&
146 		    si->blue_size == f->blue.length &&
147 		    si->blue_pos == f->blue.offset) {
148 			format = drm_format_info(vesa_formats[i].fourcc);
149 			break;
150 		}
151 	}
152 
153 	if (!format)
154 		return ERR_PTR(-EINVAL);
155 	if (format->is_color_indexed)
156 		return ERR_PTR(-EINVAL);
157 
158 	return format;
159 }
160 
161 /*
162  * VESA device
163  */
164 
165 struct vesadrm_device {
166 	struct drm_sysfb_device sysfb;
167 
168 #if defined(CONFIG_X86_32)
169 	/* VESA Protected Mode interface */
170 	struct {
171 		const u8 *PrimaryPalette;
172 	} pmi;
173 #endif
174 
175 	void (*cmap_write)(struct vesadrm_device *vesa, unsigned int index,
176 			   u16 red, u16 green, u16 blue);
177 
178 	/* modesetting */
179 	u32 formats[DRM_SYSFB_PLANE_NFORMATS(1)];
180 	struct drm_plane primary_plane;
181 	struct drm_crtc crtc;
182 	struct drm_encoder encoder;
183 	struct drm_connector connector;
184 };
185 
186 static struct vesadrm_device *to_vesadrm_device(struct drm_device *dev)
187 {
188 	return container_of(to_drm_sysfb_device(dev), struct vesadrm_device, sysfb);
189 }
190 
191 /*
192  * Palette
193  */
194 
195 static void vesadrm_vga_cmap_write(struct vesadrm_device *vesa, unsigned int index,
196 				   u16 red, u16 green, u16 blue)
197 {
198 	u8 i8, r8, g8, b8;
199 
200 	if (index > 255)
201 		return;
202 
203 	i8 = index;
204 	r8 = red >> 8;
205 	g8 = green >> 8;
206 	b8 = blue >> 8;
207 
208 	outb_p(i8, VGA_PEL_IW);
209 	outb_p(r8, VGA_PEL_D);
210 	outb_p(g8, VGA_PEL_D);
211 	outb_p(b8, VGA_PEL_D);
212 }
213 
214 #if defined(CONFIG_X86_32)
215 static void vesadrm_pmi_cmap_write(struct vesadrm_device *vesa, unsigned int index,
216 				   u16 red, u16 green, u16 blue)
217 {
218 	u32 i32 = index;
219 	struct {
220 		u8 b8;
221 		u8 g8;
222 		u8 r8;
223 		u8 x8;
224 	} PaletteEntry = {
225 		blue >> 8,
226 		green >> 8,
227 		red >> 8,
228 		0x00,
229 	};
230 
231 	if (index > 255)
232 		return;
233 
234 	__asm__ __volatile__ (
235 		"call *(%%esi)"
236 		: /* no return value */
237 		: "a" (0x4f09),
238 		  "b" (0),
239 		  "c" (1),
240 		  "d" (i32),
241 		  "D" (&PaletteEntry),
242 		  "S" (&vesa->pmi.PrimaryPalette));
243 }
244 #endif
245 
246 static void vesadrm_set_gamma_linear(struct vesadrm_device *vesa,
247 				     const struct drm_format_info *format)
248 {
249 	struct drm_device *dev = &vesa->sysfb.dev;
250 	size_t i;
251 	u16 r16, g16, b16;
252 
253 	switch (format->format) {
254 	case DRM_FORMAT_XRGB1555:
255 		for (i = 0; i < 32; ++i) {
256 			r16 = i * 8 + i / 4;
257 			r16 |= (r16 << 8) | r16;
258 			vesa->cmap_write(vesa, i, r16, r16, r16);
259 		}
260 		break;
261 	case DRM_FORMAT_RGB565:
262 		for (i = 0; i < 32; ++i) {
263 			r16 = i * 8 + i / 4;
264 			r16 |= (r16 << 8) | r16;
265 			g16 = i * 4 + i / 16;
266 			g16 |= (g16 << 8) | g16;
267 			b16 = r16;
268 			vesa->cmap_write(vesa, i, r16, g16, b16);
269 		}
270 		for (i = 32; i < 64; ++i) {
271 			g16 = i * 4 + i / 16;
272 			g16 |= (g16 << 8) | g16;
273 			vesa->cmap_write(vesa, i, 0, g16, 0);
274 		}
275 		break;
276 	case DRM_FORMAT_RGB888:
277 	case DRM_FORMAT_XRGB8888:
278 	case DRM_FORMAT_BGRX8888:
279 		for (i = 0; i < 256; ++i) {
280 			r16 = (i << 8) | i;
281 			vesa->cmap_write(vesa, i, r16, r16, r16);
282 		}
283 		break;
284 	default:
285 		drm_warn_once(dev, "Unsupported format %p4cc for gamma correction\n",
286 			      &format->format);
287 		break;
288 	}
289 }
290 
291 static void vesadrm_set_gamma_lut(struct vesadrm_device *vesa,
292 				  const struct drm_format_info *format,
293 				  struct drm_color_lut *lut)
294 {
295 	struct drm_device *dev = &vesa->sysfb.dev;
296 	size_t i;
297 	u16 r16, g16, b16;
298 
299 	switch (format->format) {
300 	case DRM_FORMAT_XRGB1555:
301 		for (i = 0; i < 32; ++i) {
302 			r16 = lut[i * 8 + i / 4].red;
303 			g16 = lut[i * 8 + i / 4].green;
304 			b16 = lut[i * 8 + i / 4].blue;
305 			vesa->cmap_write(vesa, i, r16, g16, b16);
306 		}
307 		break;
308 	case DRM_FORMAT_RGB565:
309 		for (i = 0; i < 32; ++i) {
310 			r16 = lut[i * 8 + i / 4].red;
311 			g16 = lut[i * 4 + i / 16].green;
312 			b16 = lut[i * 8 + i / 4].blue;
313 			vesa->cmap_write(vesa, i, r16, g16, b16);
314 		}
315 		for (i = 32; i < 64; ++i)
316 			vesa->cmap_write(vesa, i, 0, lut[i * 4 + i / 16].green, 0);
317 		break;
318 	case DRM_FORMAT_RGB888:
319 	case DRM_FORMAT_XRGB8888:
320 	case DRM_FORMAT_BGRX8888:
321 		for (i = 0; i < 256; ++i)
322 			vesa->cmap_write(vesa, i, lut[i].red, lut[i].green, lut[i].blue);
323 		break;
324 	default:
325 		drm_warn_once(dev, "Unsupported format %p4cc for gamma correction\n",
326 			      &format->format);
327 		break;
328 	}
329 }
330 
331 /*
332  * Modesetting
333  */
334 
335 static const u64 vesadrm_primary_plane_format_modifiers[] = {
336 	DRM_SYSFB_PLANE_FORMAT_MODIFIERS,
337 };
338 
339 static const struct drm_plane_helper_funcs vesadrm_primary_plane_helper_funcs = {
340 	DRM_SYSFB_PLANE_HELPER_FUNCS,
341 };
342 
343 static const struct drm_plane_funcs vesadrm_primary_plane_funcs = {
344 	DRM_SYSFB_PLANE_FUNCS,
345 	.destroy = drm_plane_cleanup,
346 };
347 
348 static void vesadrm_crtc_helper_atomic_flush(struct drm_crtc *crtc,
349 					     struct drm_atomic_state *state)
350 {
351 	struct drm_device *dev = crtc->dev;
352 	struct drm_sysfb_device *sysfb = to_drm_sysfb_device(dev);
353 	struct vesadrm_device *vesa = to_vesadrm_device(dev);
354 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
355 	struct drm_sysfb_crtc_state *sysfb_crtc_state = to_drm_sysfb_crtc_state(crtc_state);
356 
357 	/*
358 	 * The gamma LUT has to be reloaded after changing the primary
359 	 * plane's color format.
360 	 */
361 	if (crtc_state->enable && crtc_state->color_mgmt_changed) {
362 		if (sysfb_crtc_state->format == sysfb->fb_format) {
363 			if (crtc_state->gamma_lut)
364 				vesadrm_set_gamma_lut(vesa,
365 						      sysfb_crtc_state->format,
366 						      crtc_state->gamma_lut->data);
367 			else
368 				vesadrm_set_gamma_linear(vesa, sysfb_crtc_state->format);
369 		} else {
370 			vesadrm_set_gamma_linear(vesa, sysfb_crtc_state->format);
371 		}
372 	}
373 }
374 
375 static const struct drm_crtc_helper_funcs vesadrm_crtc_helper_funcs = {
376 	DRM_SYSFB_CRTC_HELPER_FUNCS,
377 	.atomic_flush = vesadrm_crtc_helper_atomic_flush,
378 };
379 
380 static const struct drm_crtc_funcs vesadrm_crtc_funcs = {
381 	DRM_SYSFB_CRTC_FUNCS,
382 	.destroy = drm_crtc_cleanup,
383 };
384 
385 static const struct drm_encoder_funcs vesadrm_encoder_funcs = {
386 	.destroy = drm_encoder_cleanup,
387 };
388 
389 static const struct drm_connector_helper_funcs vesadrm_connector_helper_funcs = {
390 	DRM_SYSFB_CONNECTOR_HELPER_FUNCS,
391 };
392 
393 static const struct drm_connector_funcs vesadrm_connector_funcs = {
394 	DRM_SYSFB_CONNECTOR_FUNCS,
395 	.destroy = drm_connector_cleanup,
396 };
397 
398 static const struct drm_mode_config_funcs vesadrm_mode_config_funcs = {
399 	DRM_SYSFB_MODE_CONFIG_FUNCS,
400 };
401 
402 /*
403  * Init / Cleanup
404  */
405 
406 static struct vesadrm_device *vesadrm_device_create(struct drm_driver *drv,
407 						    struct platform_device *pdev)
408 {
409 	const struct screen_info *si;
410 	const struct drm_format_info *format;
411 	int width, height, stride;
412 	u64 vsize;
413 	struct resource resbuf;
414 	struct resource *res;
415 	struct vesadrm_device *vesa;
416 	struct drm_sysfb_device *sysfb;
417 	struct drm_device *dev;
418 	struct resource *mem = NULL;
419 	void __iomem *screen_base;
420 	struct drm_plane *primary_plane;
421 	struct drm_crtc *crtc;
422 	struct drm_encoder *encoder;
423 	struct drm_connector *connector;
424 	unsigned long max_width, max_height;
425 	size_t nformats;
426 	int ret;
427 
428 	si = dev_get_platdata(&pdev->dev);
429 	if (!si)
430 		return ERR_PTR(-ENODEV);
431 	if (screen_info_video_type(si) != VIDEO_TYPE_VLFB)
432 		return ERR_PTR(-ENODEV);
433 
434 	/*
435 	 * VESA DRM driver
436 	 */
437 
438 	vesa = devm_drm_dev_alloc(&pdev->dev, drv, struct vesadrm_device, sysfb.dev);
439 	if (IS_ERR(vesa))
440 		return ERR_CAST(vesa);
441 	sysfb = &vesa->sysfb;
442 	dev = &sysfb->dev;
443 	platform_set_drvdata(pdev, dev);
444 
445 	/*
446 	 * Hardware settings
447 	 */
448 
449 	format = vesadrm_get_format_si(dev, si);
450 	if (IS_ERR(format))
451 		return ERR_CAST(format);
452 	width = vesadrm_get_width_si(dev, si);
453 	if (width < 0)
454 		return ERR_PTR(width);
455 	height = vesadrm_get_height_si(dev, si);
456 	if (height < 0)
457 		return ERR_PTR(height);
458 	res = vesadrm_get_memory_si(dev, si, &resbuf);
459 	if (!res)
460 		return ERR_PTR(-EINVAL);
461 	stride = vesadrm_get_stride_si(dev, si, format, width, height, resource_size(res));
462 	if (stride < 0)
463 		return ERR_PTR(stride);
464 	vsize = vesadrm_get_visible_size_si(dev, si, height, stride, resource_size(res));
465 	if (!vsize)
466 		return ERR_PTR(-EINVAL);
467 
468 	drm_dbg(dev, "framebuffer format=%p4cc, size=%dx%d, stride=%d bytes\n",
469 		&format->format, width, height, stride);
470 
471 	if (!__screen_info_vbe_mode_nonvga(si)) {
472 		vesa->cmap_write = vesadrm_vga_cmap_write;
473 #if defined(CONFIG_X86_32)
474 	} else {
475 		phys_addr_t pmi_base = __screen_info_vesapm_info_base(si);
476 		const u16 *pmi_addr = phys_to_virt(pmi_base);
477 
478 		vesa->pmi.PrimaryPalette = (u8 *)pmi_addr + pmi_addr[2];
479 		vesa->cmap_write = vesadrm_pmi_cmap_write;
480 #endif
481 	}
482 
483 #ifdef CONFIG_X86
484 	if (drm_edid_header_is_valid(edid_info.dummy) == 8)
485 		sysfb->edid = edid_info.dummy;
486 #endif
487 	sysfb->fb_mode = drm_sysfb_mode(width, height, 0, 0);
488 	sysfb->fb_format = format;
489 	sysfb->fb_pitch = stride;
490 	if (vesa->cmap_write)
491 		sysfb->fb_gamma_lut_size = VESADRM_GAMMA_LUT_SIZE;
492 
493 	/*
494 	 * Memory management
495 	 */
496 
497 	ret = devm_aperture_acquire_for_platform_device(pdev, res->start, vsize);
498 	if (ret) {
499 		drm_err(dev, "could not acquire memory range %pr: %d\n", res, ret);
500 		return ERR_PTR(ret);
501 	}
502 
503 	drm_dbg(dev, "using I/O memory framebuffer at %pr\n", res);
504 
505 	mem = devm_request_mem_region(&pdev->dev, res->start, vsize, drv->name);
506 	if (!mem) {
507 		/*
508 		 * We cannot make this fatal. Sometimes this comes from magic
509 		 * spaces our resource handlers simply don't know about. Use
510 		 * the I/O-memory resource as-is and try to map that instead.
511 		 */
512 		drm_warn(dev, "could not acquire memory region %pr\n", res);
513 		mem = res;
514 	}
515 
516 	screen_base = devm_ioremap_wc(&pdev->dev, mem->start, resource_size(mem));
517 	if (!screen_base)
518 		return ERR_PTR(-ENOMEM);
519 	iosys_map_set_vaddr_iomem(&sysfb->fb_addr, screen_base);
520 
521 	/*
522 	 * Modesetting
523 	 */
524 
525 	ret = drmm_mode_config_init(dev);
526 	if (ret)
527 		return ERR_PTR(ret);
528 
529 	max_width = max_t(unsigned long, width, DRM_SHADOW_PLANE_MAX_WIDTH);
530 	max_height = max_t(unsigned long, height, DRM_SHADOW_PLANE_MAX_HEIGHT);
531 
532 	dev->mode_config.min_width = width;
533 	dev->mode_config.max_width = max_width;
534 	dev->mode_config.min_height = height;
535 	dev->mode_config.max_height = max_height;
536 	dev->mode_config.preferred_depth = format->depth;
537 	dev->mode_config.funcs = &vesadrm_mode_config_funcs;
538 
539 	/* Primary plane */
540 
541 	nformats = drm_fb_build_fourcc_list(dev, &format->format, 1,
542 					    vesa->formats, ARRAY_SIZE(vesa->formats));
543 
544 	primary_plane = &vesa->primary_plane;
545 	ret = drm_universal_plane_init(dev, primary_plane, 0, &vesadrm_primary_plane_funcs,
546 				       vesa->formats, nformats,
547 				       vesadrm_primary_plane_format_modifiers,
548 				       DRM_PLANE_TYPE_PRIMARY, NULL);
549 	if (ret)
550 		return ERR_PTR(ret);
551 	drm_plane_helper_add(primary_plane, &vesadrm_primary_plane_helper_funcs);
552 	drm_plane_enable_fb_damage_clips(primary_plane);
553 
554 	/* CRTC */
555 
556 	crtc = &vesa->crtc;
557 	ret = drm_crtc_init_with_planes(dev, crtc, primary_plane, NULL,
558 					&vesadrm_crtc_funcs, NULL);
559 	if (ret)
560 		return ERR_PTR(ret);
561 	drm_crtc_helper_add(crtc, &vesadrm_crtc_helper_funcs);
562 
563 	if (sysfb->fb_gamma_lut_size) {
564 		ret = drm_mode_crtc_set_gamma_size(crtc, sysfb->fb_gamma_lut_size);
565 		if (!ret)
566 			drm_crtc_enable_color_mgmt(crtc, 0, false, sysfb->fb_gamma_lut_size);
567 	}
568 
569 	/* Encoder */
570 
571 	encoder = &vesa->encoder;
572 	ret = drm_encoder_init(dev, encoder, &vesadrm_encoder_funcs,
573 			       DRM_MODE_ENCODER_NONE, NULL);
574 	if (ret)
575 		return ERR_PTR(ret);
576 	encoder->possible_crtcs = drm_crtc_mask(crtc);
577 
578 	/* Connector */
579 
580 	connector = &vesa->connector;
581 	ret = drm_connector_init(dev, connector, &vesadrm_connector_funcs,
582 				 DRM_MODE_CONNECTOR_Unknown);
583 	if (ret)
584 		return ERR_PTR(ret);
585 	drm_connector_helper_add(connector, &vesadrm_connector_helper_funcs);
586 	drm_connector_set_panel_orientation_with_quirk(connector,
587 						       DRM_MODE_PANEL_ORIENTATION_UNKNOWN,
588 						       width, height);
589 	if (sysfb->edid)
590 		drm_connector_attach_edid_property(connector);
591 
592 	ret = drm_connector_attach_encoder(connector, encoder);
593 	if (ret)
594 		return ERR_PTR(ret);
595 
596 	drm_mode_config_reset(dev);
597 
598 	return vesa;
599 }
600 
601 /*
602  * DRM driver
603  */
604 
605 DEFINE_DRM_GEM_FOPS(vesadrm_fops);
606 
607 static struct drm_driver vesadrm_driver = {
608 	DRM_GEM_SHMEM_DRIVER_OPS,
609 	DRM_FBDEV_SHMEM_DRIVER_OPS,
610 	.name			= DRIVER_NAME,
611 	.desc			= DRIVER_DESC,
612 	.major			= DRIVER_MAJOR,
613 	.minor			= DRIVER_MINOR,
614 	.driver_features	= DRIVER_ATOMIC | DRIVER_GEM | DRIVER_MODESET,
615 	.fops			= &vesadrm_fops,
616 };
617 
618 /*
619  * Platform driver
620  */
621 
622 static int vesadrm_probe(struct platform_device *pdev)
623 {
624 	struct vesadrm_device *vesa;
625 	struct drm_sysfb_device *sysfb;
626 	struct drm_device *dev;
627 	int ret;
628 
629 	vesa = vesadrm_device_create(&vesadrm_driver, pdev);
630 	if (IS_ERR(vesa))
631 		return PTR_ERR(vesa);
632 	sysfb = &vesa->sysfb;
633 	dev = &sysfb->dev;
634 
635 	ret = drm_dev_register(dev, 0);
636 	if (ret)
637 		return ret;
638 
639 	drm_client_setup(dev, sysfb->fb_format);
640 
641 	return 0;
642 }
643 
644 static void vesadrm_remove(struct platform_device *pdev)
645 {
646 	struct drm_device *dev = platform_get_drvdata(pdev);
647 
648 	drm_dev_unplug(dev);
649 }
650 
651 static struct platform_driver vesadrm_platform_driver = {
652 	.driver = {
653 		.name = "vesa-framebuffer",
654 	},
655 	.probe = vesadrm_probe,
656 	.remove = vesadrm_remove,
657 };
658 
659 module_platform_driver(vesadrm_platform_driver);
660 
661 MODULE_DESCRIPTION(DRIVER_DESC);
662 MODULE_LICENSE("GPL");
663