summaryrefslogtreecommitdiffstats
path: root/drivers/video/fbdev/ssd1307fb.c
blob: 78ca7ffc40c2b2843f1bda10c2b7742b3bcf5f99 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for the Solomon SSD1307 OLED controller
 *
 * Copyright 2012 Free Electrons
 */

#include <linux/backlight.h>
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/pwm.h>
#include <linux/uaccess.h>
#include <linux/regulator/consumer.h>

#define SSD1307FB_DATA			0x40
#define SSD1307FB_COMMAND		0x80

#define SSD1307FB_SET_ADDRESS_MODE	0x20
#define SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL	(0x00)
#define SSD1307FB_SET_ADDRESS_MODE_VERTICAL	(0x01)
#define SSD1307FB_SET_ADDRESS_MODE_PAGE		(0x02)
#define SSD1307FB_SET_COL_RANGE		0x21
#define SSD1307FB_SET_PAGE_RANGE	0x22
#define SSD1307FB_CONTRAST		0x81
#define SSD1307FB_SET_LOOKUP_TABLE	0x91
#define	SSD1307FB_CHARGE_PUMP		0x8d
#define SSD1307FB_SEG_REMAP_ON		0xa1
#define SSD1307FB_DISPLAY_OFF		0xae
#define SSD1307FB_SET_MULTIPLEX_RATIO	0xa8
#define SSD1307FB_DISPLAY_ON		0xaf
#define SSD1307FB_START_PAGE_ADDRESS	0xb0
#define SSD1307FB_SET_DISPLAY_OFFSET	0xd3
#define	SSD1307FB_SET_CLOCK_FREQ	0xd5
#define	SSD1307FB_SET_AREA_COLOR_MODE	0xd8
#define	SSD1307FB_SET_PRECHARGE_PERIOD	0xd9
#define	SSD1307FB_SET_COM_PINS_CONFIG	0xda
#define	SSD1307FB_SET_VCOMH		0xdb

#define MAX_CONTRAST 255

#define REFRESHRATE 1

static u_int refreshrate = REFRESHRATE;
module_param(refreshrate, uint, 0);

struct ssd1307fb_par;

struct ssd1307fb_deviceinfo {
	u32 default_vcomh;
	u32 default_dclk_div;
	u32 default_dclk_frq;
	int need_pwm;
	int need_chargepump;
};

struct ssd1307fb_par {
	unsigned area_color_enable : 1;
	unsigned com_invdir : 1;
	unsigned com_lrremap : 1;
	unsigned com_seq : 1;
	unsigned lookup_table_set : 1;
	unsigned low_power : 1;
	unsigned seg_remap : 1;
	u32 com_offset;
	u32 contrast;
	u32 dclk_div;
	u32 dclk_frq;
	const struct ssd1307fb_deviceinfo *device_info;
	struct i2c_client *client;
	u32 height;
	struct fb_info *info;
	u8 lookup_table[4];
	u32 page_offset;
	u32 prechargep1;
	u32 prechargep2;
	struct pwm_device *pwm;
	u32 pwm_period;
	struct gpio_desc *reset;
	struct regulator *vbat_reg;
	u32 vcomh;
	u32 width;
};

struct ssd1307fb_array {
	u8	type;
	u8	data[0];
};

static const struct fb_fix_screeninfo ssd1307fb_fix = {
	.id		= "Solomon SSD1307",
	.type		= FB_TYPE_PACKED_PIXELS,
	.visual		= FB_VISUAL_MONO10,
	.xpanstep	= 0,
	.ypanstep	= 0,
	.ywrapstep	= 0,
	.accel		= FB_ACCEL_NONE,
};

static const struct fb_var_screeninfo ssd1307fb_var = {
	.bits_per_pixel	= 1,
	.red = { .length = 1 },
	.green = { .length = 1 },
	.blue = { .length = 1 },
};

static struct ssd1307fb_array *ssd1307fb_alloc_array(u32 len, u8 type)
{
	struct ssd1307fb_array *array;

	array = kzalloc(sizeof(struct ssd1307fb_array) + len, GFP_KERNEL);
	if (!array)
		return NULL;

	array->type = type;

	return array;
}

static int ssd1307fb_write_array(struct i2c_client *client,
				 struct ssd1307fb_array *array, u32 len)
{
	int ret;

	len += sizeof(struct ssd1307fb_array);

	ret = i2c_master_send(client, (u8 *)array, len);
	if (ret != len) {
		dev_err(&client->dev, "Couldn't send I2C command.\n");
		return ret;
	}

	return 0;
}

static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
{
	struct ssd1307fb_array *array;
	int ret;

	array = ssd1307fb_alloc_array(1, SSD1307FB_COMMAND);
	if (!array)
		return -ENOMEM;

	array->data[0] = cmd;

	ret = ssd1307fb_write_array(client, array, 1);
	kfree(array);

	return ret;
}

static void ssd1307fb_update_display(struct ssd1307fb_par *par)
{
	struct ssd1307fb_array *array;
	u8 *vmem = par->info->screen_buffer;
	unsigned int line_length = par->info->fix.line_length;
	unsigned int pages = DIV_ROUND_UP(par->height, 8);
	int i, j, k;

	array = ssd1307fb_alloc_array(par->width * pages, SSD1307FB_DATA);
	if (!array)
		return;

	/*
	 * The screen is divided in pages, each having a height of 8
	 * pixels, and the width of the screen. When sending a byte of
	 * data to the controller, it gives the 8 bits for the current
	 * column. I.e, the first byte are the 8 bits of the first
	 * column, then the 8 bits for the second column, etc.
	 *
	 *
	 * Representation of the screen, assuming it is 5 bits
	 * wide. Each letter-number combination is a bit that controls
	 * one pixel.
	 *
	 * A0 A1 A2 A3 A4
	 * B0 B1 B2 B3 B4
	 * C0 C1 C2 C3 C4
	 * D0 D1 D2 D3 D4
	 * E0 E1 E2 E3 E4
	 * F0 F1 F2 F3 F4
	 * G0 G1 G2 G3 G4
	 * H0 H1 H2 H3 H4
	 *
	 * If you want to update this screen, you need to send 5 bytes:
	 *  (1) A0 B0 C0 D0 E0 F0 G0 H0
	 *  (2) A1 B1 C1 D1 E1 F1 G1 H1
	 *  (3) A2 B2 C2 D2 E2 F2 G2 H2
	 *  (4) A3 B3 C3 D3 E3 F3 G3 H3
	 *  (5) A4 B4 C4 D4 E4 F4 G4 H4
	 */

	for (i = 0; i < pages; i++) {
		for (j = 0; j < par->width; j++) {
			int m = 8;
			u32 array_idx = i * par->width + j;
			array->data[array_idx] = 0;
			/* Last page may be partial */
			if (i + 1 == pages && par->height % 8)
				m = par->height % 8;
			for (k = 0; k < m; k++) {
				u8 byte = vmem[(8 * i + k) * line_length +
					       j / 8];
				u8 bit = (byte >> (j % 8)) & 1;
				array->data[array_idx] |= bit << k;
			}
		}
	}

	ssd1307fb_write_array(par->client, array, par->width * pages);
	kfree(array);
}


static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
		size_t count, loff_t *ppos)
{
	struct ssd1307fb_par *par = info->par;
	unsigned long total_size;
	unsigned long p = *ppos;
	void *dst;

	total_size = info->fix.smem_len;

	if (p > total_size)
		return -EINVAL;

	if (count + p > total_size)
		count = total_size - p;

	if (!count)
		return -EINVAL;

	dst = info->screen_buffer + p;

	if (copy_from_user(dst, buf, count))
		return -EFAULT;

	ssd1307fb_update_display(par);

	*ppos += count;

	return count;
}

static int ssd1307fb_blank(int blank_mode, struct fb_info *info)
{
	struct ssd1307fb_par *par = info->par;

	if (blank_mode != FB_BLANK_UNBLANK)
		return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
	else
		return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
}

static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
{
	struct ssd1307fb_par *par = info->par;
	sys_fillrect(info, rect);
	ssd1307fb_update_display(par);
}

static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
{
	struct ssd1307fb_par *par = info->par;
	sys_copyarea(info, area);
	ssd1307fb_update_display(par);
}

static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image)
{
	struct ssd1307fb_par *par = info->par;
	sys_imageblit(info, image);
	ssd1307fb_update_display(par);
}

static struct fb_ops ssd1307fb_ops = {
	.owner		= THIS_MODULE,
	.fb_read	= fb_sys_read,
	.fb_write	= ssd1307fb_write,
	.fb_blank	= ssd1307fb_blank,
	.fb_fillrect	= ssd1307fb_fillrect,
	.fb_copyarea	= ssd1307fb_copyarea,
	.fb_imageblit	= ssd1307fb_imageblit,
};

static void ssd1307fb_deferred_io(struct fb_info *info,
				struct list_head *pagelist)
{
	ssd1307fb_update_display(info->par);
}

static int ssd1307fb_init(struct ssd1307fb_par *par)
{
	int ret;
	u32 precharge, dclk, com_invdir, compins;
	struct pwm_args pargs;

	if (par->device_info->need_pwm) {
		par->pwm = pwm_get(&par->client->dev, NULL);
		if (IS_ERR(par->pwm)) {
			dev_err(&par->client->dev, "Could not get PWM from device tree!\n");
			return PTR_ERR(par->pwm);
		}

		/*
		 * FIXME: pwm_apply_args() should be removed when switching to
		 * the atomic PWM API.
		 */
		pwm_apply_args(par->pwm);

		pwm_get_args(par->pwm, &pargs);

		par->pwm_period = pargs.period;
		/* Enable the PWM */
		pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
		pwm_enable(par->pwm);

		dev_dbg(&par->client->dev, "Using PWM%d with a %dns period.\n",
			par->pwm->pwm, par->pwm_period);
	}

	/* Set initial contrast */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
	if (ret < 0)
		return ret;

	ret = ssd1307fb_write_cmd(par->client, par->contrast);
	if (ret < 0)
		return ret;

	/* Set segment re-map */
	if (par->seg_remap) {
		ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
		if (ret < 0)
			return ret;
	}

	/* Set COM direction */
	com_invdir = 0xc0 | par->com_invdir << 3;
	ret = ssd1307fb_write_cmd(par->client,  com_invdir);
	if (ret < 0)
		return ret;

	/* Set multiplex ratio value */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO);
	if (ret < 0)
		return ret;

	ret = ssd1307fb_write_cmd(par->client, par->height - 1);
	if (ret < 0)
		return ret;

	/* set display offset value */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET);
	if (ret < 0)
		return ret;

	ret = ssd1307fb_write_cmd(par->client, par->com_offset);
	if (ret < 0)
		return ret;

	/* Set clock frequency */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ);
	if (ret < 0)
		return ret;

	dclk = ((par->dclk_div - 1) & 0xf) | (par->dclk_frq & 0xf) << 4;
	ret = ssd1307fb_write_cmd(par->client, dclk);
	if (ret < 0)
		return ret;

	/* Set Set Area Color Mode ON/OFF & Low Power Display Mode */
	if (par->area_color_enable || par->low_power) {
		u32 mode;

		ret = ssd1307fb_write_cmd(par->client,
					  SSD1307FB_SET_AREA_COLOR_MODE);
		if (ret < 0)
			return ret;

		mode = (par->area_color_enable ? 0x30 : 0) |
			(par->low_power ? 5 : 0);
		ret = ssd1307fb_write_cmd(par->client, mode);
		if (ret < 0)
			return ret;
	}

	/* Set precharge period in number of ticks from the internal clock */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD);
	if (ret < 0)
		return ret;

	precharge = (par->prechargep1 & 0xf) | (par->prechargep2 & 0xf) << 4;
	ret = ssd1307fb_write_cmd(par->client, precharge);
	if (ret < 0)
		return ret;

	/* Set COM pins configuration */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG);
	if (ret < 0)
		return ret;

	compins = 0x02 | !par->com_seq << 4 | par->com_lrremap << 5;
	ret = ssd1307fb_write_cmd(par->client, compins);
	if (ret < 0)
		return ret;

	/* Set VCOMH */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH);
	if (ret < 0)
		return ret;

	ret = ssd1307fb_write_cmd(par->client, par->vcomh);
	if (ret < 0)
		return ret;

	/* Turn on the DC-DC Charge Pump */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
	if (ret < 0)
		return ret;

	ret = ssd1307fb_write_cmd(par->client,
		BIT(4) | (par->device_info->need_chargepump ? BIT(2) : 0));
	if (ret < 0)
		return ret;

	/* Set lookup table */
	if (par->lookup_table_set) {
		int i;

		ret = ssd1307fb_write_cmd(par->client,
					  SSD1307FB_SET_LOOKUP_TABLE);
		if (ret < 0)
			return ret;

		for (i = 0; i < ARRAY_SIZE(par->lookup_table); ++i) {
			u8 val = par->lookup_table[i];

			if (val < 31 || val > 63)
				dev_warn(&par->client->dev,
					 "lookup table index %d value out of range 31 <= %d <= 63\n",
					 i, val);
			ret = ssd1307fb_write_cmd(par->client, val);
			if (ret < 0)
				return ret;
		}
	}

	/* Switch to horizontal addressing mode */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_ADDRESS_MODE);
	if (ret < 0)
		return ret;

	ret = ssd1307fb_write_cmd(par->client,
				  SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL);
	if (ret < 0)
		return ret;

	/* Set column range */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
	if (ret < 0)
		return ret;

	ret = ssd1307fb_write_cmd(par->client, 0x0);
	if (ret < 0)
		return ret;

	ret = ssd1307fb_write_cmd(par->client, par->width - 1);
	if (ret < 0)
		return ret;

	/* Set page range */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
	if (ret < 0)
		return ret;

	ret = ssd1307fb_write_cmd(par->client, par->page_offset);
	if (ret < 0)
		return ret;

	ret = ssd1307fb_write_cmd(par->client,
				  par->page_offset +
				  DIV_ROUND_UP(par->height, 8) - 1);
	if (ret < 0)
		return ret;

	/* Clear the screen */
	ssd1307fb_update_display(par);

	/* Turn on the display */
	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
	if (ret < 0)
		return ret;

	return 0;
}

static int ssd1307fb_update_bl(struct backlight_device *bdev)
{
	struct ssd1307fb_par *par = bl_get_data(bdev);
	int ret;
	int brightness = bdev->props.brightness;

	par->contrast = brightness;

	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
	if (ret < 0)
		return ret;
	ret = ssd1307fb_write_cmd(par->client, par->contrast);
	if (ret < 0)
		return ret;
	return 0;
}

static int ssd1307fb_get_brightness(struct backlight_device *bdev)
{
	struct ssd1307fb_par *par = bl_get_data(bdev);

	return par->contrast;
}

static int ssd1307fb_check_fb(struct backlight_device *bdev,
				   struct fb_info *info)
{
	return (info->bl_dev == bdev);
}

static const struct backlight_ops ssd1307fb_bl_ops = {
	.options	= BL_CORE_SUSPENDRESUME,
	.update_status	= ssd1307fb_update_bl,
	.get_brightness	= ssd1307fb_get_brightness,
	.check_fb	= ssd1307fb_check_fb,
};

static struct ssd1307fb_deviceinfo ssd1307fb_ssd1305_deviceinfo = {
	.default_vcomh = 0x34,
	.default_dclk_div = 1,
	.default_dclk_frq = 7,
};

static struct ssd1307fb_deviceinfo ssd1307fb_ssd1306_deviceinfo = {
	.default_vcomh = 0x20,
	.default_dclk_div = 1,
	.default_dclk_frq = 8,
	.need_chargepump = 1,
};

static struct ssd1307fb_deviceinfo ssd1307fb_ssd1307_deviceinfo = {
	.default_vcomh = 0x20,
	.default_dclk_div = 2,
	.default_dclk_frq = 12,
	.need_pwm = 1,
};

static struct ssd1307fb_deviceinfo ssd1307fb_ssd1309_deviceinfo = {
	.default_vcomh = 0x34,
	.default_dclk_div = 1,
	.default_dclk_frq = 10,
};

static const struct of_device_id ssd1307fb_of_match[] = {
	{
		.compatible = "solomon,ssd1305fb-i2c",
		.data = (void *)&ssd1307fb_ssd1305_deviceinfo,
	},
	{
		.compatible = "solomon,ssd1306fb-i2c",
		.data = (void *)&ssd1307fb_ssd1306_deviceinfo,
	},
	{
		.compatible = "solomon,ssd1307fb-i2c",
		.data = (void *)&ssd1307fb_ssd1307_deviceinfo,
	},
	{
		.compatible = "solomon,ssd1309fb-i2c",
		.data = (void *)&ssd1307fb_ssd1309_deviceinfo,
	},
	{},
};
MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);

static int ssd1307fb_probe(struct i2c_client *client,
			   const struct i2c_device_id *id)
{
	struct backlight_device *bl;
	char bl_name[12];
	struct fb_info *info;
	struct device_node *node = client->dev.of_node;
	struct fb_deferred_io *ssd1307fb_defio;
	u32 vmem_size;
	struct ssd1307fb_par *par;
	void *vmem;
	int ret;

	if (!node) {
		dev_err(&client->dev, "No device tree data found!\n");
		return -EINVAL;
	}

	info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev);
	if (!info)
		return -ENOMEM;

	par = info->par;
	par->info = info;
	par->client = client;

	par->device_info = of_device_get_match_data(&client->dev);

	par->reset = devm_gpiod_get_optional(&client->dev, "reset",
					     GPIOD_OUT_LOW);
	if (IS_ERR(par->reset)) {
		dev_err(&client->dev, "failed to get reset gpio: %ld\n",
			PTR_ERR(par->reset));
		ret = PTR_ERR(par->reset);
		goto fb_alloc_error;
	}

	par->vbat_reg = devm_regulator_get_optional(&client->dev, "vbat");
	if (IS_ERR(par->vbat_reg)) {
		ret = PTR_ERR(par->vbat_reg);
		if (ret == -ENODEV) {
			par->vbat_reg = NULL;
		} else {
			dev_err(&client->dev, "failed to get VBAT regulator: %d\n",
				ret);
			goto fb_alloc_error;
		}
	}

	if (of_property_read_u32(node, "solomon,width", &par->width))
		par->width = 96;

	if (of_property_read_u32(node, "solomon,height", &par->height))
		par->height = 16;

	if (of_property_read_u32(node, "solomon,page-offset", &par->page_offset))
		par->page_offset = 1;

	if (of_property_read_u32(node, "solomon,com-offset", &par->com_offset))
		par->com_offset = 0;

	if (of_property_read_u32(node, "solomon,prechargep1", &par->prechargep1))
		par->prechargep1 = 2;

	if (of_property_read_u32(node, "solomon,prechargep2", &par->prechargep2))
		par->prechargep2 = 2;

	if (!of_property_read_u8_array(node, "solomon,lookup-table",
				       par->lookup_table,
				       ARRAY_SIZE(par->lookup_table)))
		par->lookup_table_set = 1;

	par->seg_remap = !of_property_read_bool(node, "solomon,segment-no-remap");
	par->com_seq = of_property_read_bool(node, "solomon,com-seq");
	par->com_lrremap = of_property_read_bool(node, "solomon,com-lrremap");
	par->com_invdir = of_property_read_bool(node, "solomon,com-invdir");
	par->area_color_enable =
		of_property_read_bool(node, "solomon,area-color-enable");
	par->low_power = of_property_read_bool(node, "solomon,low-power");

	par->contrast = 127;
	par->vcomh = par->device_info->default_vcomh;

	/* Setup display timing */
	if (of_property_read_u32(node, "solomon,dclk-div", &par->dclk_div))
		par->dclk_div = par->device_info->default_dclk_div;
	if (of_property_read_u32(node, "solomon,dclk-frq", &par->dclk_frq))
		par->dclk_frq = par->device_info->default_dclk_frq;

	vmem_size = DIV_ROUND_UP(par->width, 8) * par->height;

	vmem = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
					get_order(vmem_size));
	if (!vmem) {
		dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
		ret = -ENOMEM;
		goto fb_alloc_error;
	}

	ssd1307fb_defio = devm_kzalloc(&client->dev, sizeof(*ssd1307fb_defio),
				       GFP_KERNEL);
	if (!ssd1307fb_defio) {
		dev_err(&client->dev, "Couldn't allocate deferred io.\n");
		ret = -ENOMEM;
		goto fb_alloc_error;
	}

	ssd1307fb_defio->delay = HZ / refreshrate;
	ssd1307fb_defio->deferred_io = ssd1307fb_deferred_io;

	info->fbops = &ssd1307fb_ops;
	info->fix = ssd1307fb_fix;
	info->fix.line_length = DIV_ROUND_UP(par->width, 8);
	info->fbdefio = ssd1307fb_defio;

	info->var = ssd1307fb_var;
	info->var.xres = par->width;
	info->var.xres_virtual = par->width;
	info->var.yres = par->height;
	info->var.yres_virtual = par->height;

	info->screen_buffer = vmem;
	info->fix.smem_start = __pa(vmem);
	info->fix.smem_len = vmem_size;

	fb_deferred_io_init(info);

	i2c_set_clientdata(client, info);

	if (par->reset) {
		/* Reset the screen */
		gpiod_set_value_cansleep(par->reset, 1);
		udelay(4);
		gpiod_set_value_cansleep(par->reset, 0);
		udelay(4);
	}

	if (par->vbat_reg) {
		ret = regulator_enable(par->vbat_reg);
		if (ret) {
			dev_err(&client->dev, "failed to enable VBAT: %d\n",
				ret);
			goto reset_oled_error;
		}
	}

	ret = ssd1307fb_init(par);
	if (ret)
		goto regulator_enable_error;

	ret = register_framebuffer(info);
	if (ret) {
		dev_err(&client->dev, "Couldn't register the framebuffer\n");
		goto panel_init_error;
	}

	snprintf(bl_name, sizeof(bl_name), "ssd1307fb%d", info->node);
	bl = backlight_device_register(bl_name, &client->dev, par,
				       &ssd1307fb_bl_ops, NULL);
	if (IS_ERR(bl)) {
		ret = PTR_ERR(bl);
		dev_err(&client->dev, "unable to register backlight device: %d\n",
			ret);
		goto bl_init_error;
	}

	bl->props.brightness = par->contrast;
	bl->props.max_brightness = MAX_CONTRAST;
	info->bl_dev = bl;

	dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);

	return 0;

bl_init_error:
	unregister_framebuffer(info);
panel_init_error:
	if (par->device_info->need_pwm) {
		pwm_disable(par->pwm);
		pwm_put(par->pwm);
	}
regulator_enable_error:
	if (par->vbat_reg)
		regulator_disable(par->vbat_reg);
reset_oled_error:
	fb_deferred_io_cleanup(info);
fb_alloc_error:
	framebuffer_release(info);
	return ret;
}

static int ssd1307fb_remove(struct i2c_client *client)
{
	struct fb_info *info = i2c_get_clientdata(client);
	struct ssd1307fb_par *par = info->par;

	ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);

	backlight_device_unregister(info->bl_dev);

	unregister_framebuffer(info);
	if (par->device_info->need_pwm) {
		pwm_disable(par->pwm);
		pwm_put(par->pwm);
	}
	fb_deferred_io_cleanup(info);
	__free_pages(__va(info->fix.smem_start), get_order(info->fix.smem_len));
	framebuffer_release(info);

	return 0;
}

static const struct i2c_device_id ssd1307fb_i2c_id[] = {
	{ "ssd1305fb", 0 },
	{ "ssd1306fb", 0 },
	{ "ssd1307fb", 0 },
	{ "ssd1309fb", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id);

static struct i2c_driver ssd1307fb_driver = {
	.probe = ssd1307fb_probe,
	.remove = ssd1307fb_remove,
	.id_table = ssd1307fb_i2c_id,
	.driver = {
		.name = "ssd1307fb",
		.of_match_table = ssd1307fb_of_match,
	},
};

module_i2c_driver(ssd1307fb_driver);

MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controller");
MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
MODULE_LICENSE("GPL");