xref: /openbmc/linux/arch/arm/mach-omap2/display.c (revision 1c2f87c2)
1 /*
2  * OMAP2plus display device setup / initialization.
3  *
4  * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com/
5  *	Senthilvadivu Guruswamy
6  *	Sumit Semwal
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  *
12  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
13  * kind, whether express or implied; without even the implied warranty
14  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  */
17 
18 #include <linux/string.h>
19 #include <linux/kernel.h>
20 #include <linux/init.h>
21 #include <linux/platform_device.h>
22 #include <linux/io.h>
23 #include <linux/clk.h>
24 #include <linux/err.h>
25 #include <linux/delay.h>
26 #include <linux/of.h>
27 #include <linux/of_platform.h>
28 #include <linux/slab.h>
29 
30 #include <video/omapdss.h>
31 #include "omap_hwmod.h"
32 #include "omap_device.h"
33 #include "omap-pm.h"
34 #include "common.h"
35 
36 #include "soc.h"
37 #include "iomap.h"
38 #include "control.h"
39 #include "display.h"
40 #include "prm.h"
41 
42 #define DISPC_CONTROL		0x0040
43 #define DISPC_CONTROL2		0x0238
44 #define DISPC_CONTROL3		0x0848
45 #define DISPC_IRQSTATUS		0x0018
46 
47 #define DSS_SYSCONFIG		0x10
48 #define DSS_SYSSTATUS		0x14
49 #define DSS_CONTROL		0x40
50 #define DSS_SDI_CONTROL		0x44
51 #define DSS_PLL_CONTROL		0x48
52 
53 #define LCD_EN_MASK		(0x1 << 0)
54 #define DIGIT_EN_MASK		(0x1 << 1)
55 
56 #define FRAMEDONE_IRQ_SHIFT	0
57 #define EVSYNC_EVEN_IRQ_SHIFT	2
58 #define EVSYNC_ODD_IRQ_SHIFT	3
59 #define FRAMEDONE2_IRQ_SHIFT	22
60 #define FRAMEDONE3_IRQ_SHIFT	30
61 #define FRAMEDONETV_IRQ_SHIFT	24
62 
63 /*
64  * FRAMEDONE_IRQ_TIMEOUT: how long (in milliseconds) to wait during DISPC
65  *     reset before deciding that something has gone wrong
66  */
67 #define FRAMEDONE_IRQ_TIMEOUT		100
68 
69 static struct platform_device omap_display_device = {
70 	.name          = "omapdss",
71 	.id            = -1,
72 	.dev            = {
73 		.platform_data = NULL,
74 	},
75 };
76 
77 struct omap_dss_hwmod_data {
78 	const char *oh_name;
79 	const char *dev_name;
80 	const int id;
81 };
82 
83 static const struct omap_dss_hwmod_data omap2_dss_hwmod_data[] __initconst = {
84 	{ "dss_core", "omapdss_dss", -1 },
85 	{ "dss_dispc", "omapdss_dispc", -1 },
86 	{ "dss_rfbi", "omapdss_rfbi", -1 },
87 	{ "dss_venc", "omapdss_venc", -1 },
88 };
89 
90 static const struct omap_dss_hwmod_data omap3_dss_hwmod_data[] __initconst = {
91 	{ "dss_core", "omapdss_dss", -1 },
92 	{ "dss_dispc", "omapdss_dispc", -1 },
93 	{ "dss_rfbi", "omapdss_rfbi", -1 },
94 	{ "dss_venc", "omapdss_venc", -1 },
95 	{ "dss_dsi1", "omapdss_dsi", 0 },
96 };
97 
98 static const struct omap_dss_hwmod_data omap4_dss_hwmod_data[] __initconst = {
99 	{ "dss_core", "omapdss_dss", -1 },
100 	{ "dss_dispc", "omapdss_dispc", -1 },
101 	{ "dss_rfbi", "omapdss_rfbi", -1 },
102 	{ "dss_dsi1", "omapdss_dsi", 0 },
103 	{ "dss_dsi2", "omapdss_dsi", 1 },
104 	{ "dss_hdmi", "omapdss_hdmi", -1 },
105 };
106 
107 static int omap4_dsi_mux_pads(int dsi_id, unsigned lanes)
108 {
109 	u32 enable_mask, enable_shift;
110 	u32 pipd_mask, pipd_shift;
111 	u32 reg;
112 
113 	if (dsi_id == 0) {
114 		enable_mask = OMAP4_DSI1_LANEENABLE_MASK;
115 		enable_shift = OMAP4_DSI1_LANEENABLE_SHIFT;
116 		pipd_mask = OMAP4_DSI1_PIPD_MASK;
117 		pipd_shift = OMAP4_DSI1_PIPD_SHIFT;
118 	} else if (dsi_id == 1) {
119 		enable_mask = OMAP4_DSI2_LANEENABLE_MASK;
120 		enable_shift = OMAP4_DSI2_LANEENABLE_SHIFT;
121 		pipd_mask = OMAP4_DSI2_PIPD_MASK;
122 		pipd_shift = OMAP4_DSI2_PIPD_SHIFT;
123 	} else {
124 		return -ENODEV;
125 	}
126 
127 	reg = omap4_ctrl_pad_readl(OMAP4_CTRL_MODULE_PAD_CORE_CONTROL_DSIPHY);
128 
129 	reg &= ~enable_mask;
130 	reg &= ~pipd_mask;
131 
132 	reg |= (lanes << enable_shift) & enable_mask;
133 	reg |= (lanes << pipd_shift) & pipd_mask;
134 
135 	omap4_ctrl_pad_writel(reg, OMAP4_CTRL_MODULE_PAD_CORE_CONTROL_DSIPHY);
136 
137 	return 0;
138 }
139 
140 static int omap_dsi_enable_pads(int dsi_id, unsigned lane_mask)
141 {
142 	if (cpu_is_omap44xx())
143 		return omap4_dsi_mux_pads(dsi_id, lane_mask);
144 
145 	return 0;
146 }
147 
148 static void omap_dsi_disable_pads(int dsi_id, unsigned lane_mask)
149 {
150 	if (cpu_is_omap44xx())
151 		omap4_dsi_mux_pads(dsi_id, 0);
152 }
153 
154 static int omap_dss_set_min_bus_tput(struct device *dev, unsigned long tput)
155 {
156 	return omap_pm_set_min_bus_tput(dev, OCP_INITIATOR_AGENT, tput);
157 }
158 
159 static struct platform_device *create_dss_pdev(const char *pdev_name,
160 		int pdev_id, const char *oh_name, void *pdata, int pdata_len,
161 		struct platform_device *parent)
162 {
163 	struct platform_device *pdev;
164 	struct omap_device *od;
165 	struct omap_hwmod *ohs[1];
166 	struct omap_hwmod *oh;
167 	int r;
168 
169 	oh = omap_hwmod_lookup(oh_name);
170 	if (!oh) {
171 		pr_err("Could not look up %s\n", oh_name);
172 		r = -ENODEV;
173 		goto err;
174 	}
175 
176 	pdev = platform_device_alloc(pdev_name, pdev_id);
177 	if (!pdev) {
178 		pr_err("Could not create pdev for %s\n", pdev_name);
179 		r = -ENOMEM;
180 		goto err;
181 	}
182 
183 	if (parent != NULL)
184 		pdev->dev.parent = &parent->dev;
185 
186 	if (pdev->id != -1)
187 		dev_set_name(&pdev->dev, "%s.%d", pdev->name, pdev->id);
188 	else
189 		dev_set_name(&pdev->dev, "%s", pdev->name);
190 
191 	ohs[0] = oh;
192 	od = omap_device_alloc(pdev, ohs, 1);
193 	if (IS_ERR(od)) {
194 		pr_err("Could not alloc omap_device for %s\n", pdev_name);
195 		r = -ENOMEM;
196 		goto err;
197 	}
198 
199 	r = platform_device_add_data(pdev, pdata, pdata_len);
200 	if (r) {
201 		pr_err("Could not set pdata for %s\n", pdev_name);
202 		goto err;
203 	}
204 
205 	r = omap_device_register(pdev);
206 	if (r) {
207 		pr_err("Could not register omap_device for %s\n", pdev_name);
208 		goto err;
209 	}
210 
211 	return pdev;
212 
213 err:
214 	return ERR_PTR(r);
215 }
216 
217 static struct platform_device *create_simple_dss_pdev(const char *pdev_name,
218 		int pdev_id, void *pdata, int pdata_len,
219 		struct platform_device *parent)
220 {
221 	struct platform_device *pdev;
222 	int r;
223 
224 	pdev = platform_device_alloc(pdev_name, pdev_id);
225 	if (!pdev) {
226 		pr_err("Could not create pdev for %s\n", pdev_name);
227 		r = -ENOMEM;
228 		goto err;
229 	}
230 
231 	if (parent != NULL)
232 		pdev->dev.parent = &parent->dev;
233 
234 	if (pdev->id != -1)
235 		dev_set_name(&pdev->dev, "%s.%d", pdev->name, pdev->id);
236 	else
237 		dev_set_name(&pdev->dev, "%s", pdev->name);
238 
239 	r = platform_device_add_data(pdev, pdata, pdata_len);
240 	if (r) {
241 		pr_err("Could not set pdata for %s\n", pdev_name);
242 		goto err;
243 	}
244 
245 	r = platform_device_add(pdev);
246 	if (r) {
247 		pr_err("Could not register platform_device for %s\n", pdev_name);
248 		goto err;
249 	}
250 
251 	return pdev;
252 
253 err:
254 	return ERR_PTR(r);
255 }
256 
257 static enum omapdss_version __init omap_display_get_version(void)
258 {
259 	if (cpu_is_omap24xx())
260 		return OMAPDSS_VER_OMAP24xx;
261 	else if (cpu_is_omap3630())
262 		return OMAPDSS_VER_OMAP3630;
263 	else if (cpu_is_omap34xx()) {
264 		if (soc_is_am35xx()) {
265 			return OMAPDSS_VER_AM35xx;
266 		} else {
267 			if (omap_rev() < OMAP3430_REV_ES3_0)
268 				return OMAPDSS_VER_OMAP34xx_ES1;
269 			else
270 				return OMAPDSS_VER_OMAP34xx_ES3;
271 		}
272 	} else if (omap_rev() == OMAP4430_REV_ES1_0)
273 		return OMAPDSS_VER_OMAP4430_ES1;
274 	else if (omap_rev() == OMAP4430_REV_ES2_0 ||
275 			omap_rev() == OMAP4430_REV_ES2_1 ||
276 			omap_rev() == OMAP4430_REV_ES2_2)
277 		return OMAPDSS_VER_OMAP4430_ES2;
278 	else if (cpu_is_omap44xx())
279 		return OMAPDSS_VER_OMAP4;
280 	else if (soc_is_omap54xx())
281 		return OMAPDSS_VER_OMAP5;
282 	else
283 		return OMAPDSS_VER_UNKNOWN;
284 }
285 
286 int __init omap_display_init(struct omap_dss_board_info *board_data)
287 {
288 	int r = 0;
289 	struct platform_device *pdev;
290 	int i, oh_count;
291 	const struct omap_dss_hwmod_data *curr_dss_hwmod;
292 	struct platform_device *dss_pdev;
293 	enum omapdss_version ver;
294 
295 	/* create omapdss device */
296 
297 	ver = omap_display_get_version();
298 
299 	if (ver == OMAPDSS_VER_UNKNOWN) {
300 		pr_err("DSS not supported on this SoC\n");
301 		return -ENODEV;
302 	}
303 
304 	board_data->version = ver;
305 	board_data->dsi_enable_pads = omap_dsi_enable_pads;
306 	board_data->dsi_disable_pads = omap_dsi_disable_pads;
307 	board_data->set_min_bus_tput = omap_dss_set_min_bus_tput;
308 
309 	omap_display_device.dev.platform_data = board_data;
310 
311 	r = platform_device_register(&omap_display_device);
312 	if (r < 0) {
313 		pr_err("Unable to register omapdss device\n");
314 		return r;
315 	}
316 
317 	/* create devices for dss hwmods */
318 
319 	if (cpu_is_omap24xx()) {
320 		curr_dss_hwmod = omap2_dss_hwmod_data;
321 		oh_count = ARRAY_SIZE(omap2_dss_hwmod_data);
322 	} else if (cpu_is_omap34xx()) {
323 		curr_dss_hwmod = omap3_dss_hwmod_data;
324 		oh_count = ARRAY_SIZE(omap3_dss_hwmod_data);
325 	} else {
326 		curr_dss_hwmod = omap4_dss_hwmod_data;
327 		oh_count = ARRAY_SIZE(omap4_dss_hwmod_data);
328 	}
329 
330 	/*
331 	 * First create the pdev for dss_core, which is used as a parent device
332 	 * by the other dss pdevs. Note: dss_core has to be the first item in
333 	 * the hwmod list.
334 	 */
335 	dss_pdev = create_dss_pdev(curr_dss_hwmod[0].dev_name,
336 			curr_dss_hwmod[0].id,
337 			curr_dss_hwmod[0].oh_name,
338 			board_data, sizeof(*board_data),
339 			NULL);
340 
341 	if (IS_ERR(dss_pdev)) {
342 		pr_err("Could not build omap_device for %s\n",
343 				curr_dss_hwmod[0].oh_name);
344 
345 		return PTR_ERR(dss_pdev);
346 	}
347 
348 	for (i = 1; i < oh_count; i++) {
349 		pdev = create_dss_pdev(curr_dss_hwmod[i].dev_name,
350 				curr_dss_hwmod[i].id,
351 				curr_dss_hwmod[i].oh_name,
352 				board_data, sizeof(*board_data),
353 				dss_pdev);
354 
355 		if (IS_ERR(pdev)) {
356 			pr_err("Could not build omap_device for %s\n",
357 					curr_dss_hwmod[i].oh_name);
358 
359 			return PTR_ERR(pdev);
360 		}
361 	}
362 
363 	/* Create devices for DPI and SDI */
364 
365 	pdev = create_simple_dss_pdev("omapdss_dpi", 0,
366 			board_data, sizeof(*board_data), dss_pdev);
367 	if (IS_ERR(pdev)) {
368 		pr_err("Could not build platform_device for omapdss_dpi\n");
369 		return PTR_ERR(pdev);
370 	}
371 
372 	if (cpu_is_omap34xx()) {
373 		pdev = create_simple_dss_pdev("omapdss_sdi", 0,
374 				board_data, sizeof(*board_data), dss_pdev);
375 		if (IS_ERR(pdev)) {
376 			pr_err("Could not build platform_device for omapdss_sdi\n");
377 			return PTR_ERR(pdev);
378 		}
379 	}
380 
381 	/* create DRM device */
382 	r = omap_init_drm();
383 	if (r < 0) {
384 		pr_err("Unable to register omapdrm device\n");
385 		return r;
386 	}
387 
388 	/* create vrfb device */
389 	r = omap_init_vrfb();
390 	if (r < 0) {
391 		pr_err("Unable to register omapvrfb device\n");
392 		return r;
393 	}
394 
395 	/* create FB device */
396 	r = omap_init_fb();
397 	if (r < 0) {
398 		pr_err("Unable to register omapfb device\n");
399 		return r;
400 	}
401 
402 	/* create V4L2 display device */
403 	r = omap_init_vout();
404 	if (r < 0) {
405 		pr_err("Unable to register omap_vout device\n");
406 		return r;
407 	}
408 
409 	return 0;
410 }
411 
412 static void dispc_disable_outputs(void)
413 {
414 	u32 v, irq_mask = 0;
415 	bool lcd_en, digit_en, lcd2_en = false, lcd3_en = false;
416 	int i;
417 	struct omap_dss_dispc_dev_attr *da;
418 	struct omap_hwmod *oh;
419 
420 	oh = omap_hwmod_lookup("dss_dispc");
421 	if (!oh) {
422 		WARN(1, "display: could not disable outputs during reset - could not find dss_dispc hwmod\n");
423 		return;
424 	}
425 
426 	if (!oh->dev_attr) {
427 		pr_err("display: could not disable outputs during reset due to missing dev_attr\n");
428 		return;
429 	}
430 
431 	da = (struct omap_dss_dispc_dev_attr *)oh->dev_attr;
432 
433 	/* store value of LCDENABLE and DIGITENABLE bits */
434 	v = omap_hwmod_read(oh, DISPC_CONTROL);
435 	lcd_en = v & LCD_EN_MASK;
436 	digit_en = v & DIGIT_EN_MASK;
437 
438 	/* store value of LCDENABLE for LCD2 */
439 	if (da->manager_count > 2) {
440 		v = omap_hwmod_read(oh, DISPC_CONTROL2);
441 		lcd2_en = v & LCD_EN_MASK;
442 	}
443 
444 	/* store value of LCDENABLE for LCD3 */
445 	if (da->manager_count > 3) {
446 		v = omap_hwmod_read(oh, DISPC_CONTROL3);
447 		lcd3_en = v & LCD_EN_MASK;
448 	}
449 
450 	if (!(lcd_en | digit_en | lcd2_en | lcd3_en))
451 		return; /* no managers currently enabled */
452 
453 	/*
454 	 * If any manager was enabled, we need to disable it before
455 	 * DSS clocks are disabled or DISPC module is reset
456 	 */
457 	if (lcd_en)
458 		irq_mask |= 1 << FRAMEDONE_IRQ_SHIFT;
459 
460 	if (digit_en) {
461 		if (da->has_framedonetv_irq) {
462 			irq_mask |= 1 << FRAMEDONETV_IRQ_SHIFT;
463 		} else {
464 			irq_mask |= 1 << EVSYNC_EVEN_IRQ_SHIFT |
465 				1 << EVSYNC_ODD_IRQ_SHIFT;
466 		}
467 	}
468 
469 	if (lcd2_en)
470 		irq_mask |= 1 << FRAMEDONE2_IRQ_SHIFT;
471 	if (lcd3_en)
472 		irq_mask |= 1 << FRAMEDONE3_IRQ_SHIFT;
473 
474 	/*
475 	 * clear any previous FRAMEDONE, FRAMEDONETV,
476 	 * EVSYNC_EVEN/ODD, FRAMEDONE2 or FRAMEDONE3 interrupts
477 	 */
478 	omap_hwmod_write(irq_mask, oh, DISPC_IRQSTATUS);
479 
480 	/* disable LCD and TV managers */
481 	v = omap_hwmod_read(oh, DISPC_CONTROL);
482 	v &= ~(LCD_EN_MASK | DIGIT_EN_MASK);
483 	omap_hwmod_write(v, oh, DISPC_CONTROL);
484 
485 	/* disable LCD2 manager */
486 	if (da->manager_count > 2) {
487 		v = omap_hwmod_read(oh, DISPC_CONTROL2);
488 		v &= ~LCD_EN_MASK;
489 		omap_hwmod_write(v, oh, DISPC_CONTROL2);
490 	}
491 
492 	/* disable LCD3 manager */
493 	if (da->manager_count > 3) {
494 		v = omap_hwmod_read(oh, DISPC_CONTROL3);
495 		v &= ~LCD_EN_MASK;
496 		omap_hwmod_write(v, oh, DISPC_CONTROL3);
497 	}
498 
499 	i = 0;
500 	while ((omap_hwmod_read(oh, DISPC_IRQSTATUS) & irq_mask) !=
501 	       irq_mask) {
502 		i++;
503 		if (i > FRAMEDONE_IRQ_TIMEOUT) {
504 			pr_err("didn't get FRAMEDONE1/2/3 or TV interrupt\n");
505 			break;
506 		}
507 		mdelay(1);
508 	}
509 }
510 
511 int omap_dss_reset(struct omap_hwmod *oh)
512 {
513 	struct omap_hwmod_opt_clk *oc;
514 	int c = 0;
515 	int i, r;
516 
517 	if (!(oh->class->sysc->sysc_flags & SYSS_HAS_RESET_STATUS)) {
518 		pr_err("dss_core: hwmod data doesn't contain reset data\n");
519 		return -EINVAL;
520 	}
521 
522 	for (i = oh->opt_clks_cnt, oc = oh->opt_clks; i > 0; i--, oc++)
523 		if (oc->_clk)
524 			clk_prepare_enable(oc->_clk);
525 
526 	dispc_disable_outputs();
527 
528 	/* clear SDI registers */
529 	if (cpu_is_omap3430()) {
530 		omap_hwmod_write(0x0, oh, DSS_SDI_CONTROL);
531 		omap_hwmod_write(0x0, oh, DSS_PLL_CONTROL);
532 	}
533 
534 	/*
535 	 * clear DSS_CONTROL register to switch DSS clock sources to
536 	 * PRCM clock, if any
537 	 */
538 	omap_hwmod_write(0x0, oh, DSS_CONTROL);
539 
540 	omap_test_timeout((omap_hwmod_read(oh, oh->class->sysc->syss_offs)
541 				& SYSS_RESETDONE_MASK),
542 			MAX_MODULE_SOFTRESET_WAIT, c);
543 
544 	if (c == MAX_MODULE_SOFTRESET_WAIT)
545 		pr_warning("dss_core: waiting for reset to finish failed\n");
546 	else
547 		pr_debug("dss_core: softreset done\n");
548 
549 	for (i = oh->opt_clks_cnt, oc = oh->opt_clks; i > 0; i--, oc++)
550 		if (oc->_clk)
551 			clk_disable_unprepare(oc->_clk);
552 
553 	r = (c == MAX_MODULE_SOFTRESET_WAIT) ? -ETIMEDOUT : 0;
554 
555 	return r;
556 }
557 
558 /* list of 'compatible' nodes to convert to omapdss specific */
559 static const char * const dss_compat_conv_list[] __initconst = {
560 	"composite-connector",
561 	"dvi-connector",
562 	"hdmi-connector",
563 	"panel-dpi",
564 	"panel-dsi-cm",
565 	"sony,acx565akm",
566 	"svideo-connector",
567 	"ti,tfp410",
568 	"ti,tpd12s015",
569 };
570 
571 /* prepend compatible string with "omapdss," */
572 static __init void omapdss_omapify_node(struct device_node *node,
573 	const char *compat)
574 {
575 	char *new_compat;
576 	struct property *prop;
577 
578 	new_compat = kasprintf(GFP_KERNEL, "omapdss,%s", compat);
579 
580 	prop = kzalloc(sizeof(*prop), GFP_KERNEL);
581 
582 	if (!prop) {
583 		pr_err("omapdss_omapify_node: kzalloc failed\n");
584 		return;
585 	}
586 
587 	prop->name = "compatible";
588 	prop->value = new_compat;
589 	prop->length = strlen(new_compat) + 1;
590 
591 	of_update_property(node, prop);
592 }
593 
594 /*
595  * As omapdss panel drivers are omapdss specific, but we want to define the
596  * DT-data in generic manner, we convert the compatible strings of the panel
597  * nodes from "panel-foo" to "omapdss,panel-foo". This way we can have both
598  * correct DT data and omapdss specific drivers.
599  *
600  * When we get generic panel drivers to the kernel, this will be removed.
601  */
602 void __init omapdss_early_init_of(void)
603 {
604 	int i;
605 
606 	for (i = 0; i < ARRAY_SIZE(dss_compat_conv_list); ++i) {
607 		const char *compat = dss_compat_conv_list[i];
608 		struct device_node *node = NULL;
609 
610 		while ((node = of_find_compatible_node(node, NULL, compat))) {
611 			if (!of_device_is_available(node))
612 				continue;
613 
614 			omapdss_omapify_node(node, compat);
615 		}
616 	}
617 }
618 
619 struct device_node * __init omapdss_find_dss_of_node(void)
620 {
621 	struct device_node *node;
622 
623 	node = of_find_compatible_node(NULL, NULL, "ti,omap2-dss");
624 	if (node)
625 		return node;
626 
627 	node = of_find_compatible_node(NULL, NULL, "ti,omap3-dss");
628 	if (node)
629 		return node;
630 
631 	node = of_find_compatible_node(NULL, NULL, "ti,omap4-dss");
632 	if (node)
633 		return node;
634 
635 	return NULL;
636 }
637 
638 int __init omapdss_init_of(void)
639 {
640 	int r;
641 	enum omapdss_version ver;
642 	struct device_node *node;
643 	struct platform_device *pdev;
644 
645 	static struct omap_dss_board_info board_data = {
646 		.dsi_enable_pads = omap_dsi_enable_pads,
647 		.dsi_disable_pads = omap_dsi_disable_pads,
648 		.set_min_bus_tput = omap_dss_set_min_bus_tput,
649 	};
650 
651 	/* only create dss helper devices if dss is enabled in the .dts */
652 
653 	node = omapdss_find_dss_of_node();
654 	if (!node)
655 		return 0;
656 
657 	if (!of_device_is_available(node))
658 		return 0;
659 
660 	ver = omap_display_get_version();
661 
662 	if (ver == OMAPDSS_VER_UNKNOWN) {
663 		pr_err("DSS not supported on this SoC\n");
664 		return -ENODEV;
665 	}
666 
667 	pdev = of_find_device_by_node(node);
668 
669 	if (!pdev) {
670 		pr_err("Unable to find DSS platform device\n");
671 		return -ENODEV;
672 	}
673 
674 	r = of_platform_populate(node, NULL, NULL, &pdev->dev);
675 	if (r) {
676 		pr_err("Unable to populate DSS submodule devices\n");
677 		return r;
678 	}
679 
680 	board_data.version = ver;
681 
682 	omap_display_device.dev.platform_data = &board_data;
683 
684 	r = platform_device_register(&omap_display_device);
685 	if (r < 0) {
686 		pr_err("Unable to register omapdss device\n");
687 		return r;
688 	}
689 
690 	/* create DRM device */
691 	r = omap_init_drm();
692 	if (r < 0) {
693 		pr_err("Unable to register omapdrm device\n");
694 		return r;
695 	}
696 
697 	/* create vrfb device */
698 	r = omap_init_vrfb();
699 	if (r < 0) {
700 		pr_err("Unable to register omapvrfb device\n");
701 		return r;
702 	}
703 
704 	/* create FB device */
705 	r = omap_init_fb();
706 	if (r < 0) {
707 		pr_err("Unable to register omapfb device\n");
708 		return r;
709 	}
710 
711 	/* create V4L2 display device */
712 	r = omap_init_vout();
713 	if (r < 0) {
714 		pr_err("Unable to register omap_vout device\n");
715 		return r;
716 	}
717 
718 	return 0;
719 }
720