xref: /openbmc/linux/drivers/video/fbdev/ssd1307fb.c (revision 6f4eaea2)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Driver for the Solomon SSD1307 OLED controller
4  *
5  * Copyright 2012 Free Electrons
6  */
7 
8 #include <linux/backlight.h>
9 #include <linux/delay.h>
10 #include <linux/fb.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/i2c.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/property.h>
16 #include <linux/pwm.h>
17 #include <linux/uaccess.h>
18 #include <linux/regulator/consumer.h>
19 
20 #define SSD1307FB_DATA			0x40
21 #define SSD1307FB_COMMAND		0x80
22 
23 #define SSD1307FB_SET_ADDRESS_MODE	0x20
24 #define SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL	(0x00)
25 #define SSD1307FB_SET_ADDRESS_MODE_VERTICAL	(0x01)
26 #define SSD1307FB_SET_ADDRESS_MODE_PAGE		(0x02)
27 #define SSD1307FB_SET_COL_RANGE		0x21
28 #define SSD1307FB_SET_PAGE_RANGE	0x22
29 #define SSD1307FB_CONTRAST		0x81
30 #define SSD1307FB_SET_LOOKUP_TABLE	0x91
31 #define	SSD1307FB_CHARGE_PUMP		0x8d
32 #define SSD1307FB_SEG_REMAP_ON		0xa1
33 #define SSD1307FB_DISPLAY_OFF		0xae
34 #define SSD1307FB_SET_MULTIPLEX_RATIO	0xa8
35 #define SSD1307FB_DISPLAY_ON		0xaf
36 #define SSD1307FB_START_PAGE_ADDRESS	0xb0
37 #define SSD1307FB_SET_DISPLAY_OFFSET	0xd3
38 #define	SSD1307FB_SET_CLOCK_FREQ	0xd5
39 #define	SSD1307FB_SET_AREA_COLOR_MODE	0xd8
40 #define	SSD1307FB_SET_PRECHARGE_PERIOD	0xd9
41 #define	SSD1307FB_SET_COM_PINS_CONFIG	0xda
42 #define	SSD1307FB_SET_VCOMH		0xdb
43 
44 #define MAX_CONTRAST 255
45 
46 #define REFRESHRATE 1
47 
48 static u_int refreshrate = REFRESHRATE;
49 module_param(refreshrate, uint, 0);
50 
51 struct ssd1307fb_deviceinfo {
52 	u32 default_vcomh;
53 	u32 default_dclk_div;
54 	u32 default_dclk_frq;
55 	int need_pwm;
56 	int need_chargepump;
57 };
58 
59 struct ssd1307fb_par {
60 	unsigned area_color_enable : 1;
61 	unsigned com_invdir : 1;
62 	unsigned com_lrremap : 1;
63 	unsigned com_seq : 1;
64 	unsigned lookup_table_set : 1;
65 	unsigned low_power : 1;
66 	unsigned seg_remap : 1;
67 	u32 com_offset;
68 	u32 contrast;
69 	u32 dclk_div;
70 	u32 dclk_frq;
71 	const struct ssd1307fb_deviceinfo *device_info;
72 	struct i2c_client *client;
73 	u32 height;
74 	struct fb_info *info;
75 	u8 lookup_table[4];
76 	u32 page_offset;
77 	u32 col_offset;
78 	u32 prechargep1;
79 	u32 prechargep2;
80 	struct pwm_device *pwm;
81 	struct gpio_desc *reset;
82 	struct regulator *vbat_reg;
83 	u32 vcomh;
84 	u32 width;
85 };
86 
87 struct ssd1307fb_array {
88 	u8	type;
89 	u8	data[];
90 };
91 
92 static const struct fb_fix_screeninfo ssd1307fb_fix = {
93 	.id		= "Solomon SSD1307",
94 	.type		= FB_TYPE_PACKED_PIXELS,
95 	.visual		= FB_VISUAL_MONO10,
96 	.xpanstep	= 0,
97 	.ypanstep	= 0,
98 	.ywrapstep	= 0,
99 	.accel		= FB_ACCEL_NONE,
100 };
101 
102 static const struct fb_var_screeninfo ssd1307fb_var = {
103 	.bits_per_pixel	= 1,
104 	.red = { .length = 1 },
105 	.green = { .length = 1 },
106 	.blue = { .length = 1 },
107 };
108 
109 static struct ssd1307fb_array *ssd1307fb_alloc_array(u32 len, u8 type)
110 {
111 	struct ssd1307fb_array *array;
112 
113 	array = kzalloc(sizeof(struct ssd1307fb_array) + len, GFP_KERNEL);
114 	if (!array)
115 		return NULL;
116 
117 	array->type = type;
118 
119 	return array;
120 }
121 
122 static int ssd1307fb_write_array(struct i2c_client *client,
123 				 struct ssd1307fb_array *array, u32 len)
124 {
125 	int ret;
126 
127 	len += sizeof(struct ssd1307fb_array);
128 
129 	ret = i2c_master_send(client, (u8 *)array, len);
130 	if (ret != len) {
131 		dev_err(&client->dev, "Couldn't send I2C command.\n");
132 		return ret;
133 	}
134 
135 	return 0;
136 }
137 
138 static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
139 {
140 	struct ssd1307fb_array *array;
141 	int ret;
142 
143 	array = ssd1307fb_alloc_array(1, SSD1307FB_COMMAND);
144 	if (!array)
145 		return -ENOMEM;
146 
147 	array->data[0] = cmd;
148 
149 	ret = ssd1307fb_write_array(client, array, 1);
150 	kfree(array);
151 
152 	return ret;
153 }
154 
155 static void ssd1307fb_update_display(struct ssd1307fb_par *par)
156 {
157 	struct ssd1307fb_array *array;
158 	u8 *vmem = par->info->screen_buffer;
159 	unsigned int line_length = par->info->fix.line_length;
160 	unsigned int pages = DIV_ROUND_UP(par->height, 8);
161 	int i, j, k;
162 
163 	array = ssd1307fb_alloc_array(par->width * pages, SSD1307FB_DATA);
164 	if (!array)
165 		return;
166 
167 	/*
168 	 * The screen is divided in pages, each having a height of 8
169 	 * pixels, and the width of the screen. When sending a byte of
170 	 * data to the controller, it gives the 8 bits for the current
171 	 * column. I.e, the first byte are the 8 bits of the first
172 	 * column, then the 8 bits for the second column, etc.
173 	 *
174 	 *
175 	 * Representation of the screen, assuming it is 5 bits
176 	 * wide. Each letter-number combination is a bit that controls
177 	 * one pixel.
178 	 *
179 	 * A0 A1 A2 A3 A4
180 	 * B0 B1 B2 B3 B4
181 	 * C0 C1 C2 C3 C4
182 	 * D0 D1 D2 D3 D4
183 	 * E0 E1 E2 E3 E4
184 	 * F0 F1 F2 F3 F4
185 	 * G0 G1 G2 G3 G4
186 	 * H0 H1 H2 H3 H4
187 	 *
188 	 * If you want to update this screen, you need to send 5 bytes:
189 	 *  (1) A0 B0 C0 D0 E0 F0 G0 H0
190 	 *  (2) A1 B1 C1 D1 E1 F1 G1 H1
191 	 *  (3) A2 B2 C2 D2 E2 F2 G2 H2
192 	 *  (4) A3 B3 C3 D3 E3 F3 G3 H3
193 	 *  (5) A4 B4 C4 D4 E4 F4 G4 H4
194 	 */
195 
196 	for (i = 0; i < pages; i++) {
197 		for (j = 0; j < par->width; j++) {
198 			int m = 8;
199 			u32 array_idx = i * par->width + j;
200 			array->data[array_idx] = 0;
201 			/* Last page may be partial */
202 			if (i + 1 == pages && par->height % 8)
203 				m = par->height % 8;
204 			for (k = 0; k < m; k++) {
205 				u8 byte = vmem[(8 * i + k) * line_length +
206 					       j / 8];
207 				u8 bit = (byte >> (j % 8)) & 1;
208 				array->data[array_idx] |= bit << k;
209 			}
210 		}
211 	}
212 
213 	ssd1307fb_write_array(par->client, array, par->width * pages);
214 	kfree(array);
215 }
216 
217 
218 static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
219 		size_t count, loff_t *ppos)
220 {
221 	struct ssd1307fb_par *par = info->par;
222 	unsigned long total_size;
223 	unsigned long p = *ppos;
224 	void *dst;
225 
226 	total_size = info->fix.smem_len;
227 
228 	if (p > total_size)
229 		return -EINVAL;
230 
231 	if (count + p > total_size)
232 		count = total_size - p;
233 
234 	if (!count)
235 		return -EINVAL;
236 
237 	dst = info->screen_buffer + p;
238 
239 	if (copy_from_user(dst, buf, count))
240 		return -EFAULT;
241 
242 	ssd1307fb_update_display(par);
243 
244 	*ppos += count;
245 
246 	return count;
247 }
248 
249 static int ssd1307fb_blank(int blank_mode, struct fb_info *info)
250 {
251 	struct ssd1307fb_par *par = info->par;
252 
253 	if (blank_mode != FB_BLANK_UNBLANK)
254 		return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
255 	else
256 		return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
257 }
258 
259 static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
260 {
261 	struct ssd1307fb_par *par = info->par;
262 	sys_fillrect(info, rect);
263 	ssd1307fb_update_display(par);
264 }
265 
266 static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
267 {
268 	struct ssd1307fb_par *par = info->par;
269 	sys_copyarea(info, area);
270 	ssd1307fb_update_display(par);
271 }
272 
273 static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image)
274 {
275 	struct ssd1307fb_par *par = info->par;
276 	sys_imageblit(info, image);
277 	ssd1307fb_update_display(par);
278 }
279 
280 static const struct fb_ops ssd1307fb_ops = {
281 	.owner		= THIS_MODULE,
282 	.fb_read	= fb_sys_read,
283 	.fb_write	= ssd1307fb_write,
284 	.fb_blank	= ssd1307fb_blank,
285 	.fb_fillrect	= ssd1307fb_fillrect,
286 	.fb_copyarea	= ssd1307fb_copyarea,
287 	.fb_imageblit	= ssd1307fb_imageblit,
288 };
289 
290 static void ssd1307fb_deferred_io(struct fb_info *info,
291 				struct list_head *pagelist)
292 {
293 	ssd1307fb_update_display(info->par);
294 }
295 
296 static int ssd1307fb_init(struct ssd1307fb_par *par)
297 {
298 	struct pwm_state pwmstate;
299 	int ret;
300 	u32 precharge, dclk, com_invdir, compins;
301 
302 	if (par->device_info->need_pwm) {
303 		par->pwm = pwm_get(&par->client->dev, NULL);
304 		if (IS_ERR(par->pwm)) {
305 			dev_err(&par->client->dev, "Could not get PWM from device tree!\n");
306 			return PTR_ERR(par->pwm);
307 		}
308 
309 		pwm_init_state(par->pwm, &pwmstate);
310 		pwm_set_relative_duty_cycle(&pwmstate, 50, 100);
311 		pwm_apply_state(par->pwm, &pwmstate);
312 
313 		/* Enable the PWM */
314 		pwm_enable(par->pwm);
315 
316 		dev_dbg(&par->client->dev, "Using PWM%d with a %lluns period.\n",
317 			par->pwm->pwm, pwm_get_period(par->pwm));
318 	}
319 
320 	/* Set initial contrast */
321 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
322 	if (ret < 0)
323 		return ret;
324 
325 	ret = ssd1307fb_write_cmd(par->client, par->contrast);
326 	if (ret < 0)
327 		return ret;
328 
329 	/* Set segment re-map */
330 	if (par->seg_remap) {
331 		ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
332 		if (ret < 0)
333 			return ret;
334 	}
335 
336 	/* Set COM direction */
337 	com_invdir = 0xc0 | par->com_invdir << 3;
338 	ret = ssd1307fb_write_cmd(par->client,  com_invdir);
339 	if (ret < 0)
340 		return ret;
341 
342 	/* Set multiplex ratio value */
343 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO);
344 	if (ret < 0)
345 		return ret;
346 
347 	ret = ssd1307fb_write_cmd(par->client, par->height - 1);
348 	if (ret < 0)
349 		return ret;
350 
351 	/* set display offset value */
352 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET);
353 	if (ret < 0)
354 		return ret;
355 
356 	ret = ssd1307fb_write_cmd(par->client, par->com_offset);
357 	if (ret < 0)
358 		return ret;
359 
360 	/* Set clock frequency */
361 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ);
362 	if (ret < 0)
363 		return ret;
364 
365 	dclk = ((par->dclk_div - 1) & 0xf) | (par->dclk_frq & 0xf) << 4;
366 	ret = ssd1307fb_write_cmd(par->client, dclk);
367 	if (ret < 0)
368 		return ret;
369 
370 	/* Set Set Area Color Mode ON/OFF & Low Power Display Mode */
371 	if (par->area_color_enable || par->low_power) {
372 		u32 mode;
373 
374 		ret = ssd1307fb_write_cmd(par->client,
375 					  SSD1307FB_SET_AREA_COLOR_MODE);
376 		if (ret < 0)
377 			return ret;
378 
379 		mode = (par->area_color_enable ? 0x30 : 0) |
380 			(par->low_power ? 5 : 0);
381 		ret = ssd1307fb_write_cmd(par->client, mode);
382 		if (ret < 0)
383 			return ret;
384 	}
385 
386 	/* Set precharge period in number of ticks from the internal clock */
387 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD);
388 	if (ret < 0)
389 		return ret;
390 
391 	precharge = (par->prechargep1 & 0xf) | (par->prechargep2 & 0xf) << 4;
392 	ret = ssd1307fb_write_cmd(par->client, precharge);
393 	if (ret < 0)
394 		return ret;
395 
396 	/* Set COM pins configuration */
397 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG);
398 	if (ret < 0)
399 		return ret;
400 
401 	compins = 0x02 | !par->com_seq << 4 | par->com_lrremap << 5;
402 	ret = ssd1307fb_write_cmd(par->client, compins);
403 	if (ret < 0)
404 		return ret;
405 
406 	/* Set VCOMH */
407 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH);
408 	if (ret < 0)
409 		return ret;
410 
411 	ret = ssd1307fb_write_cmd(par->client, par->vcomh);
412 	if (ret < 0)
413 		return ret;
414 
415 	/* Turn on the DC-DC Charge Pump */
416 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
417 	if (ret < 0)
418 		return ret;
419 
420 	ret = ssd1307fb_write_cmd(par->client,
421 		BIT(4) | (par->device_info->need_chargepump ? BIT(2) : 0));
422 	if (ret < 0)
423 		return ret;
424 
425 	/* Set lookup table */
426 	if (par->lookup_table_set) {
427 		int i;
428 
429 		ret = ssd1307fb_write_cmd(par->client,
430 					  SSD1307FB_SET_LOOKUP_TABLE);
431 		if (ret < 0)
432 			return ret;
433 
434 		for (i = 0; i < ARRAY_SIZE(par->lookup_table); ++i) {
435 			u8 val = par->lookup_table[i];
436 
437 			if (val < 31 || val > 63)
438 				dev_warn(&par->client->dev,
439 					 "lookup table index %d value out of range 31 <= %d <= 63\n",
440 					 i, val);
441 			ret = ssd1307fb_write_cmd(par->client, val);
442 			if (ret < 0)
443 				return ret;
444 		}
445 	}
446 
447 	/* Switch to horizontal addressing mode */
448 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_ADDRESS_MODE);
449 	if (ret < 0)
450 		return ret;
451 
452 	ret = ssd1307fb_write_cmd(par->client,
453 				  SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL);
454 	if (ret < 0)
455 		return ret;
456 
457 	/* Set column range */
458 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
459 	if (ret < 0)
460 		return ret;
461 
462 	ret = ssd1307fb_write_cmd(par->client, par->col_offset);
463 	if (ret < 0)
464 		return ret;
465 
466 	ret = ssd1307fb_write_cmd(par->client, par->col_offset + par->width - 1);
467 	if (ret < 0)
468 		return ret;
469 
470 	/* Set page range */
471 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
472 	if (ret < 0)
473 		return ret;
474 
475 	ret = ssd1307fb_write_cmd(par->client, par->page_offset);
476 	if (ret < 0)
477 		return ret;
478 
479 	ret = ssd1307fb_write_cmd(par->client,
480 				  par->page_offset +
481 				  DIV_ROUND_UP(par->height, 8) - 1);
482 	if (ret < 0)
483 		return ret;
484 
485 	/* Clear the screen */
486 	ssd1307fb_update_display(par);
487 
488 	/* Turn on the display */
489 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
490 	if (ret < 0)
491 		return ret;
492 
493 	return 0;
494 }
495 
496 static int ssd1307fb_update_bl(struct backlight_device *bdev)
497 {
498 	struct ssd1307fb_par *par = bl_get_data(bdev);
499 	int ret;
500 	int brightness = bdev->props.brightness;
501 
502 	par->contrast = brightness;
503 
504 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
505 	if (ret < 0)
506 		return ret;
507 	ret = ssd1307fb_write_cmd(par->client, par->contrast);
508 	if (ret < 0)
509 		return ret;
510 	return 0;
511 }
512 
513 static int ssd1307fb_get_brightness(struct backlight_device *bdev)
514 {
515 	struct ssd1307fb_par *par = bl_get_data(bdev);
516 
517 	return par->contrast;
518 }
519 
520 static int ssd1307fb_check_fb(struct backlight_device *bdev,
521 				   struct fb_info *info)
522 {
523 	return (info->bl_dev == bdev);
524 }
525 
526 static const struct backlight_ops ssd1307fb_bl_ops = {
527 	.options	= BL_CORE_SUSPENDRESUME,
528 	.update_status	= ssd1307fb_update_bl,
529 	.get_brightness	= ssd1307fb_get_brightness,
530 	.check_fb	= ssd1307fb_check_fb,
531 };
532 
533 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1305_deviceinfo = {
534 	.default_vcomh = 0x34,
535 	.default_dclk_div = 1,
536 	.default_dclk_frq = 7,
537 };
538 
539 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1306_deviceinfo = {
540 	.default_vcomh = 0x20,
541 	.default_dclk_div = 1,
542 	.default_dclk_frq = 8,
543 	.need_chargepump = 1,
544 };
545 
546 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1307_deviceinfo = {
547 	.default_vcomh = 0x20,
548 	.default_dclk_div = 2,
549 	.default_dclk_frq = 12,
550 	.need_pwm = 1,
551 };
552 
553 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1309_deviceinfo = {
554 	.default_vcomh = 0x34,
555 	.default_dclk_div = 1,
556 	.default_dclk_frq = 10,
557 };
558 
559 static const struct of_device_id ssd1307fb_of_match[] = {
560 	{
561 		.compatible = "solomon,ssd1305fb-i2c",
562 		.data = (void *)&ssd1307fb_ssd1305_deviceinfo,
563 	},
564 	{
565 		.compatible = "solomon,ssd1306fb-i2c",
566 		.data = (void *)&ssd1307fb_ssd1306_deviceinfo,
567 	},
568 	{
569 		.compatible = "solomon,ssd1307fb-i2c",
570 		.data = (void *)&ssd1307fb_ssd1307_deviceinfo,
571 	},
572 	{
573 		.compatible = "solomon,ssd1309fb-i2c",
574 		.data = (void *)&ssd1307fb_ssd1309_deviceinfo,
575 	},
576 	{},
577 };
578 MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
579 
580 static int ssd1307fb_probe(struct i2c_client *client)
581 {
582 	struct device *dev = &client->dev;
583 	struct backlight_device *bl;
584 	char bl_name[12];
585 	struct fb_info *info;
586 	struct fb_deferred_io *ssd1307fb_defio;
587 	u32 vmem_size;
588 	struct ssd1307fb_par *par;
589 	void *vmem;
590 	int ret;
591 
592 	info = framebuffer_alloc(sizeof(struct ssd1307fb_par), dev);
593 	if (!info)
594 		return -ENOMEM;
595 
596 	par = info->par;
597 	par->info = info;
598 	par->client = client;
599 
600 	par->device_info = device_get_match_data(dev);
601 
602 	par->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
603 	if (IS_ERR(par->reset)) {
604 		dev_err(dev, "failed to get reset gpio: %ld\n",
605 			PTR_ERR(par->reset));
606 		ret = PTR_ERR(par->reset);
607 		goto fb_alloc_error;
608 	}
609 
610 	par->vbat_reg = devm_regulator_get_optional(dev, "vbat");
611 	if (IS_ERR(par->vbat_reg)) {
612 		ret = PTR_ERR(par->vbat_reg);
613 		if (ret == -ENODEV) {
614 			par->vbat_reg = NULL;
615 		} else {
616 			dev_err(dev, "failed to get VBAT regulator: %d\n", ret);
617 			goto fb_alloc_error;
618 		}
619 	}
620 
621 	if (device_property_read_u32(dev, "solomon,width", &par->width))
622 		par->width = 96;
623 
624 	if (device_property_read_u32(dev, "solomon,height", &par->height))
625 		par->height = 16;
626 
627 	if (device_property_read_u32(dev, "solomon,page-offset", &par->page_offset))
628 		par->page_offset = 1;
629 
630 	if (device_property_read_u32(dev, "solomon,col-offset", &par->col_offset))
631 		par->col_offset = 0;
632 
633 	if (device_property_read_u32(dev, "solomon,com-offset", &par->com_offset))
634 		par->com_offset = 0;
635 
636 	if (device_property_read_u32(dev, "solomon,prechargep1", &par->prechargep1))
637 		par->prechargep1 = 2;
638 
639 	if (device_property_read_u32(dev, "solomon,prechargep2", &par->prechargep2))
640 		par->prechargep2 = 2;
641 
642 	if (!device_property_read_u8_array(dev, "solomon,lookup-table",
643 					   par->lookup_table,
644 					   ARRAY_SIZE(par->lookup_table)))
645 		par->lookup_table_set = 1;
646 
647 	par->seg_remap = !device_property_read_bool(dev, "solomon,segment-no-remap");
648 	par->com_seq = device_property_read_bool(dev, "solomon,com-seq");
649 	par->com_lrremap = device_property_read_bool(dev, "solomon,com-lrremap");
650 	par->com_invdir = device_property_read_bool(dev, "solomon,com-invdir");
651 	par->area_color_enable =
652 		device_property_read_bool(dev, "solomon,area-color-enable");
653 	par->low_power = device_property_read_bool(dev, "solomon,low-power");
654 
655 	par->contrast = 127;
656 	par->vcomh = par->device_info->default_vcomh;
657 
658 	/* Setup display timing */
659 	if (device_property_read_u32(dev, "solomon,dclk-div", &par->dclk_div))
660 		par->dclk_div = par->device_info->default_dclk_div;
661 	if (device_property_read_u32(dev, "solomon,dclk-frq", &par->dclk_frq))
662 		par->dclk_frq = par->device_info->default_dclk_frq;
663 
664 	vmem_size = DIV_ROUND_UP(par->width, 8) * par->height;
665 
666 	vmem = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
667 					get_order(vmem_size));
668 	if (!vmem) {
669 		dev_err(dev, "Couldn't allocate graphical memory.\n");
670 		ret = -ENOMEM;
671 		goto fb_alloc_error;
672 	}
673 
674 	ssd1307fb_defio = devm_kzalloc(dev, sizeof(*ssd1307fb_defio),
675 				       GFP_KERNEL);
676 	if (!ssd1307fb_defio) {
677 		dev_err(dev, "Couldn't allocate deferred io.\n");
678 		ret = -ENOMEM;
679 		goto fb_alloc_error;
680 	}
681 
682 	ssd1307fb_defio->delay = HZ / refreshrate;
683 	ssd1307fb_defio->deferred_io = ssd1307fb_deferred_io;
684 
685 	info->fbops = &ssd1307fb_ops;
686 	info->fix = ssd1307fb_fix;
687 	info->fix.line_length = DIV_ROUND_UP(par->width, 8);
688 	info->fbdefio = ssd1307fb_defio;
689 
690 	info->var = ssd1307fb_var;
691 	info->var.xres = par->width;
692 	info->var.xres_virtual = par->width;
693 	info->var.yres = par->height;
694 	info->var.yres_virtual = par->height;
695 
696 	info->screen_buffer = vmem;
697 	info->fix.smem_start = __pa(vmem);
698 	info->fix.smem_len = vmem_size;
699 
700 	fb_deferred_io_init(info);
701 
702 	i2c_set_clientdata(client, info);
703 
704 	if (par->reset) {
705 		/* Reset the screen */
706 		gpiod_set_value_cansleep(par->reset, 1);
707 		udelay(4);
708 		gpiod_set_value_cansleep(par->reset, 0);
709 		udelay(4);
710 	}
711 
712 	if (par->vbat_reg) {
713 		ret = regulator_enable(par->vbat_reg);
714 		if (ret) {
715 			dev_err(dev, "failed to enable VBAT: %d\n", ret);
716 			goto reset_oled_error;
717 		}
718 	}
719 
720 	ret = ssd1307fb_init(par);
721 	if (ret)
722 		goto regulator_enable_error;
723 
724 	ret = register_framebuffer(info);
725 	if (ret) {
726 		dev_err(dev, "Couldn't register the framebuffer\n");
727 		goto panel_init_error;
728 	}
729 
730 	snprintf(bl_name, sizeof(bl_name), "ssd1307fb%d", info->node);
731 	bl = backlight_device_register(bl_name, dev, par, &ssd1307fb_bl_ops,
732 				       NULL);
733 	if (IS_ERR(bl)) {
734 		ret = PTR_ERR(bl);
735 		dev_err(dev, "unable to register backlight device: %d\n", ret);
736 		goto bl_init_error;
737 	}
738 
739 	bl->props.brightness = par->contrast;
740 	bl->props.max_brightness = MAX_CONTRAST;
741 	info->bl_dev = bl;
742 
743 	dev_info(dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
744 
745 	return 0;
746 
747 bl_init_error:
748 	unregister_framebuffer(info);
749 panel_init_error:
750 	if (par->device_info->need_pwm) {
751 		pwm_disable(par->pwm);
752 		pwm_put(par->pwm);
753 	}
754 regulator_enable_error:
755 	if (par->vbat_reg)
756 		regulator_disable(par->vbat_reg);
757 reset_oled_error:
758 	fb_deferred_io_cleanup(info);
759 fb_alloc_error:
760 	framebuffer_release(info);
761 	return ret;
762 }
763 
764 static int ssd1307fb_remove(struct i2c_client *client)
765 {
766 	struct fb_info *info = i2c_get_clientdata(client);
767 	struct ssd1307fb_par *par = info->par;
768 
769 	ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
770 
771 	backlight_device_unregister(info->bl_dev);
772 
773 	unregister_framebuffer(info);
774 	if (par->device_info->need_pwm) {
775 		pwm_disable(par->pwm);
776 		pwm_put(par->pwm);
777 	}
778 	if (par->vbat_reg)
779 		regulator_disable(par->vbat_reg);
780 	fb_deferred_io_cleanup(info);
781 	__free_pages(__va(info->fix.smem_start), get_order(info->fix.smem_len));
782 	framebuffer_release(info);
783 
784 	return 0;
785 }
786 
787 static const struct i2c_device_id ssd1307fb_i2c_id[] = {
788 	{ "ssd1305fb", 0 },
789 	{ "ssd1306fb", 0 },
790 	{ "ssd1307fb", 0 },
791 	{ "ssd1309fb", 0 },
792 	{ }
793 };
794 MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id);
795 
796 static struct i2c_driver ssd1307fb_driver = {
797 	.probe_new = ssd1307fb_probe,
798 	.remove = ssd1307fb_remove,
799 	.id_table = ssd1307fb_i2c_id,
800 	.driver = {
801 		.name = "ssd1307fb",
802 		.of_match_table = ssd1307fb_of_match,
803 	},
804 };
805 
806 module_i2c_driver(ssd1307fb_driver);
807 
808 MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controller");
809 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
810 MODULE_LICENSE("GPL");
811