xref: /linux/drivers/video/fbdev/ssd1307fb.c (revision 8a79db5e83a5d52c74e6f3c40d6f312cf899213e)
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/of_device.h>
16 #include <linux/of_gpio.h>
17 #include <linux/pwm.h>
18 #include <linux/uaccess.h>
19 #include <linux/regulator/consumer.h>
20 
21 #define SSD1307FB_DATA			0x40
22 #define SSD1307FB_COMMAND		0x80
23 
24 #define SSD1307FB_SET_ADDRESS_MODE	0x20
25 #define SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL	(0x00)
26 #define SSD1307FB_SET_ADDRESS_MODE_VERTICAL	(0x01)
27 #define SSD1307FB_SET_ADDRESS_MODE_PAGE		(0x02)
28 #define SSD1307FB_SET_COL_RANGE		0x21
29 #define SSD1307FB_SET_PAGE_RANGE	0x22
30 #define SSD1307FB_CONTRAST		0x81
31 #define SSD1307FB_SET_LOOKUP_TABLE	0x91
32 #define	SSD1307FB_CHARGE_PUMP		0x8d
33 #define SSD1307FB_SEG_REMAP_ON		0xa1
34 #define SSD1307FB_DISPLAY_OFF		0xae
35 #define SSD1307FB_SET_MULTIPLEX_RATIO	0xa8
36 #define SSD1307FB_DISPLAY_ON		0xaf
37 #define SSD1307FB_START_PAGE_ADDRESS	0xb0
38 #define SSD1307FB_SET_DISPLAY_OFFSET	0xd3
39 #define	SSD1307FB_SET_CLOCK_FREQ	0xd5
40 #define	SSD1307FB_SET_AREA_COLOR_MODE	0xd8
41 #define	SSD1307FB_SET_PRECHARGE_PERIOD	0xd9
42 #define	SSD1307FB_SET_COM_PINS_CONFIG	0xda
43 #define	SSD1307FB_SET_VCOMH		0xdb
44 
45 #define MAX_CONTRAST 255
46 
47 #define REFRESHRATE 1
48 
49 static u_int refreshrate = REFRESHRATE;
50 module_param(refreshrate, uint, 0);
51 
52 struct ssd1307fb_par;
53 
54 struct ssd1307fb_deviceinfo {
55 	u32 default_vcomh;
56 	u32 default_dclk_div;
57 	u32 default_dclk_frq;
58 	int need_pwm;
59 	int need_chargepump;
60 };
61 
62 struct ssd1307fb_par {
63 	unsigned area_color_enable : 1;
64 	unsigned com_invdir : 1;
65 	unsigned com_lrremap : 1;
66 	unsigned com_seq : 1;
67 	unsigned lookup_table_set : 1;
68 	unsigned low_power : 1;
69 	unsigned seg_remap : 1;
70 	u32 com_offset;
71 	u32 contrast;
72 	u32 dclk_div;
73 	u32 dclk_frq;
74 	const struct ssd1307fb_deviceinfo *device_info;
75 	struct i2c_client *client;
76 	u32 height;
77 	struct fb_info *info;
78 	u8 lookup_table[4];
79 	u32 page_offset;
80 	u32 prechargep1;
81 	u32 prechargep2;
82 	struct pwm_device *pwm;
83 	u32 pwm_period;
84 	struct gpio_desc *reset;
85 	struct regulator *vbat_reg;
86 	u32 vcomh;
87 	u32 width;
88 };
89 
90 struct ssd1307fb_array {
91 	u8	type;
92 	u8	data[0];
93 };
94 
95 static const struct fb_fix_screeninfo ssd1307fb_fix = {
96 	.id		= "Solomon SSD1307",
97 	.type		= FB_TYPE_PACKED_PIXELS,
98 	.visual		= FB_VISUAL_MONO10,
99 	.xpanstep	= 0,
100 	.ypanstep	= 0,
101 	.ywrapstep	= 0,
102 	.accel		= FB_ACCEL_NONE,
103 };
104 
105 static const struct fb_var_screeninfo ssd1307fb_var = {
106 	.bits_per_pixel	= 1,
107 	.red = { .length = 1 },
108 	.green = { .length = 1 },
109 	.blue = { .length = 1 },
110 };
111 
112 static struct ssd1307fb_array *ssd1307fb_alloc_array(u32 len, u8 type)
113 {
114 	struct ssd1307fb_array *array;
115 
116 	array = kzalloc(sizeof(struct ssd1307fb_array) + len, GFP_KERNEL);
117 	if (!array)
118 		return NULL;
119 
120 	array->type = type;
121 
122 	return array;
123 }
124 
125 static int ssd1307fb_write_array(struct i2c_client *client,
126 				 struct ssd1307fb_array *array, u32 len)
127 {
128 	int ret;
129 
130 	len += sizeof(struct ssd1307fb_array);
131 
132 	ret = i2c_master_send(client, (u8 *)array, len);
133 	if (ret != len) {
134 		dev_err(&client->dev, "Couldn't send I2C command.\n");
135 		return ret;
136 	}
137 
138 	return 0;
139 }
140 
141 static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
142 {
143 	struct ssd1307fb_array *array;
144 	int ret;
145 
146 	array = ssd1307fb_alloc_array(1, SSD1307FB_COMMAND);
147 	if (!array)
148 		return -ENOMEM;
149 
150 	array->data[0] = cmd;
151 
152 	ret = ssd1307fb_write_array(client, array, 1);
153 	kfree(array);
154 
155 	return ret;
156 }
157 
158 static void ssd1307fb_update_display(struct ssd1307fb_par *par)
159 {
160 	struct ssd1307fb_array *array;
161 	u8 *vmem = par->info->screen_buffer;
162 	unsigned int line_length = par->info->fix.line_length;
163 	unsigned int pages = DIV_ROUND_UP(par->height, 8);
164 	int i, j, k;
165 
166 	array = ssd1307fb_alloc_array(par->width * pages, SSD1307FB_DATA);
167 	if (!array)
168 		return;
169 
170 	/*
171 	 * The screen is divided in pages, each having a height of 8
172 	 * pixels, and the width of the screen. When sending a byte of
173 	 * data to the controller, it gives the 8 bits for the current
174 	 * column. I.e, the first byte are the 8 bits of the first
175 	 * column, then the 8 bits for the second column, etc.
176 	 *
177 	 *
178 	 * Representation of the screen, assuming it is 5 bits
179 	 * wide. Each letter-number combination is a bit that controls
180 	 * one pixel.
181 	 *
182 	 * A0 A1 A2 A3 A4
183 	 * B0 B1 B2 B3 B4
184 	 * C0 C1 C2 C3 C4
185 	 * D0 D1 D2 D3 D4
186 	 * E0 E1 E2 E3 E4
187 	 * F0 F1 F2 F3 F4
188 	 * G0 G1 G2 G3 G4
189 	 * H0 H1 H2 H3 H4
190 	 *
191 	 * If you want to update this screen, you need to send 5 bytes:
192 	 *  (1) A0 B0 C0 D0 E0 F0 G0 H0
193 	 *  (2) A1 B1 C1 D1 E1 F1 G1 H1
194 	 *  (3) A2 B2 C2 D2 E2 F2 G2 H2
195 	 *  (4) A3 B3 C3 D3 E3 F3 G3 H3
196 	 *  (5) A4 B4 C4 D4 E4 F4 G4 H4
197 	 */
198 
199 	for (i = 0; i < pages; i++) {
200 		for (j = 0; j < par->width; j++) {
201 			int m = 8;
202 			u32 array_idx = i * par->width + j;
203 			array->data[array_idx] = 0;
204 			/* Last page may be partial */
205 			if (i + 1 == pages && par->height % 8)
206 				m = par->height % 8;
207 			for (k = 0; k < m; k++) {
208 				u8 byte = vmem[(8 * i + k) * line_length +
209 					       j / 8];
210 				u8 bit = (byte >> (j % 8)) & 1;
211 				array->data[array_idx] |= bit << k;
212 			}
213 		}
214 	}
215 
216 	ssd1307fb_write_array(par->client, array, par->width * pages);
217 	kfree(array);
218 }
219 
220 
221 static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
222 		size_t count, loff_t *ppos)
223 {
224 	struct ssd1307fb_par *par = info->par;
225 	unsigned long total_size;
226 	unsigned long p = *ppos;
227 	void *dst;
228 
229 	total_size = info->fix.smem_len;
230 
231 	if (p > total_size)
232 		return -EINVAL;
233 
234 	if (count + p > total_size)
235 		count = total_size - p;
236 
237 	if (!count)
238 		return -EINVAL;
239 
240 	dst = info->screen_buffer + p;
241 
242 	if (copy_from_user(dst, buf, count))
243 		return -EFAULT;
244 
245 	ssd1307fb_update_display(par);
246 
247 	*ppos += count;
248 
249 	return count;
250 }
251 
252 static int ssd1307fb_blank(int blank_mode, struct fb_info *info)
253 {
254 	struct ssd1307fb_par *par = info->par;
255 
256 	if (blank_mode != FB_BLANK_UNBLANK)
257 		return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
258 	else
259 		return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
260 }
261 
262 static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
263 {
264 	struct ssd1307fb_par *par = info->par;
265 	sys_fillrect(info, rect);
266 	ssd1307fb_update_display(par);
267 }
268 
269 static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
270 {
271 	struct ssd1307fb_par *par = info->par;
272 	sys_copyarea(info, area);
273 	ssd1307fb_update_display(par);
274 }
275 
276 static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image)
277 {
278 	struct ssd1307fb_par *par = info->par;
279 	sys_imageblit(info, image);
280 	ssd1307fb_update_display(par);
281 }
282 
283 static struct fb_ops ssd1307fb_ops = {
284 	.owner		= THIS_MODULE,
285 	.fb_read	= fb_sys_read,
286 	.fb_write	= ssd1307fb_write,
287 	.fb_blank	= ssd1307fb_blank,
288 	.fb_fillrect	= ssd1307fb_fillrect,
289 	.fb_copyarea	= ssd1307fb_copyarea,
290 	.fb_imageblit	= ssd1307fb_imageblit,
291 };
292 
293 static void ssd1307fb_deferred_io(struct fb_info *info,
294 				struct list_head *pagelist)
295 {
296 	ssd1307fb_update_display(info->par);
297 }
298 
299 static int ssd1307fb_init(struct ssd1307fb_par *par)
300 {
301 	int ret;
302 	u32 precharge, dclk, com_invdir, compins;
303 	struct pwm_args pargs;
304 
305 	if (par->device_info->need_pwm) {
306 		par->pwm = pwm_get(&par->client->dev, NULL);
307 		if (IS_ERR(par->pwm)) {
308 			dev_err(&par->client->dev, "Could not get PWM from device tree!\n");
309 			return PTR_ERR(par->pwm);
310 		}
311 
312 		/*
313 		 * FIXME: pwm_apply_args() should be removed when switching to
314 		 * the atomic PWM API.
315 		 */
316 		pwm_apply_args(par->pwm);
317 
318 		pwm_get_args(par->pwm, &pargs);
319 
320 		par->pwm_period = pargs.period;
321 		/* Enable the PWM */
322 		pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
323 		pwm_enable(par->pwm);
324 
325 		dev_dbg(&par->client->dev, "Using PWM%d with a %dns period.\n",
326 			par->pwm->pwm, par->pwm_period);
327 	}
328 
329 	/* Set initial contrast */
330 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
331 	if (ret < 0)
332 		return ret;
333 
334 	ret = ssd1307fb_write_cmd(par->client, par->contrast);
335 	if (ret < 0)
336 		return ret;
337 
338 	/* Set segment re-map */
339 	if (par->seg_remap) {
340 		ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
341 		if (ret < 0)
342 			return ret;
343 	}
344 
345 	/* Set COM direction */
346 	com_invdir = 0xc0 | par->com_invdir << 3;
347 	ret = ssd1307fb_write_cmd(par->client,  com_invdir);
348 	if (ret < 0)
349 		return ret;
350 
351 	/* Set multiplex ratio value */
352 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO);
353 	if (ret < 0)
354 		return ret;
355 
356 	ret = ssd1307fb_write_cmd(par->client, par->height - 1);
357 	if (ret < 0)
358 		return ret;
359 
360 	/* set display offset value */
361 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET);
362 	if (ret < 0)
363 		return ret;
364 
365 	ret = ssd1307fb_write_cmd(par->client, par->com_offset);
366 	if (ret < 0)
367 		return ret;
368 
369 	/* Set clock frequency */
370 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ);
371 	if (ret < 0)
372 		return ret;
373 
374 	dclk = ((par->dclk_div - 1) & 0xf) | (par->dclk_frq & 0xf) << 4;
375 	ret = ssd1307fb_write_cmd(par->client, dclk);
376 	if (ret < 0)
377 		return ret;
378 
379 	/* Set Set Area Color Mode ON/OFF & Low Power Display Mode */
380 	if (par->area_color_enable || par->low_power) {
381 		u32 mode;
382 
383 		ret = ssd1307fb_write_cmd(par->client,
384 					  SSD1307FB_SET_AREA_COLOR_MODE);
385 		if (ret < 0)
386 			return ret;
387 
388 		mode = (par->area_color_enable ? 0x30 : 0) |
389 			(par->low_power ? 5 : 0);
390 		ret = ssd1307fb_write_cmd(par->client, mode);
391 		if (ret < 0)
392 			return ret;
393 	}
394 
395 	/* Set precharge period in number of ticks from the internal clock */
396 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD);
397 	if (ret < 0)
398 		return ret;
399 
400 	precharge = (par->prechargep1 & 0xf) | (par->prechargep2 & 0xf) << 4;
401 	ret = ssd1307fb_write_cmd(par->client, precharge);
402 	if (ret < 0)
403 		return ret;
404 
405 	/* Set COM pins configuration */
406 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG);
407 	if (ret < 0)
408 		return ret;
409 
410 	compins = 0x02 | !par->com_seq << 4 | par->com_lrremap << 5;
411 	ret = ssd1307fb_write_cmd(par->client, compins);
412 	if (ret < 0)
413 		return ret;
414 
415 	/* Set VCOMH */
416 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH);
417 	if (ret < 0)
418 		return ret;
419 
420 	ret = ssd1307fb_write_cmd(par->client, par->vcomh);
421 	if (ret < 0)
422 		return ret;
423 
424 	/* Turn on the DC-DC Charge Pump */
425 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
426 	if (ret < 0)
427 		return ret;
428 
429 	ret = ssd1307fb_write_cmd(par->client,
430 		BIT(4) | (par->device_info->need_chargepump ? BIT(2) : 0));
431 	if (ret < 0)
432 		return ret;
433 
434 	/* Set lookup table */
435 	if (par->lookup_table_set) {
436 		int i;
437 
438 		ret = ssd1307fb_write_cmd(par->client,
439 					  SSD1307FB_SET_LOOKUP_TABLE);
440 		if (ret < 0)
441 			return ret;
442 
443 		for (i = 0; i < ARRAY_SIZE(par->lookup_table); ++i) {
444 			u8 val = par->lookup_table[i];
445 
446 			if (val < 31 || val > 63)
447 				dev_warn(&par->client->dev,
448 					 "lookup table index %d value out of range 31 <= %d <= 63\n",
449 					 i, val);
450 			ret = ssd1307fb_write_cmd(par->client, val);
451 			if (ret < 0)
452 				return ret;
453 		}
454 	}
455 
456 	/* Switch to horizontal addressing mode */
457 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_ADDRESS_MODE);
458 	if (ret < 0)
459 		return ret;
460 
461 	ret = ssd1307fb_write_cmd(par->client,
462 				  SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL);
463 	if (ret < 0)
464 		return ret;
465 
466 	/* Set column range */
467 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
468 	if (ret < 0)
469 		return ret;
470 
471 	ret = ssd1307fb_write_cmd(par->client, 0x0);
472 	if (ret < 0)
473 		return ret;
474 
475 	ret = ssd1307fb_write_cmd(par->client, par->width - 1);
476 	if (ret < 0)
477 		return ret;
478 
479 	/* Set page range */
480 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
481 	if (ret < 0)
482 		return ret;
483 
484 	ret = ssd1307fb_write_cmd(par->client, par->page_offset);
485 	if (ret < 0)
486 		return ret;
487 
488 	ret = ssd1307fb_write_cmd(par->client,
489 				  par->page_offset +
490 				  DIV_ROUND_UP(par->height, 8) - 1);
491 	if (ret < 0)
492 		return ret;
493 
494 	/* Clear the screen */
495 	ssd1307fb_update_display(par);
496 
497 	/* Turn on the display */
498 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
499 	if (ret < 0)
500 		return ret;
501 
502 	return 0;
503 }
504 
505 static int ssd1307fb_update_bl(struct backlight_device *bdev)
506 {
507 	struct ssd1307fb_par *par = bl_get_data(bdev);
508 	int ret;
509 	int brightness = bdev->props.brightness;
510 
511 	par->contrast = brightness;
512 
513 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
514 	if (ret < 0)
515 		return ret;
516 	ret = ssd1307fb_write_cmd(par->client, par->contrast);
517 	if (ret < 0)
518 		return ret;
519 	return 0;
520 }
521 
522 static int ssd1307fb_get_brightness(struct backlight_device *bdev)
523 {
524 	struct ssd1307fb_par *par = bl_get_data(bdev);
525 
526 	return par->contrast;
527 }
528 
529 static int ssd1307fb_check_fb(struct backlight_device *bdev,
530 				   struct fb_info *info)
531 {
532 	return (info->bl_dev == bdev);
533 }
534 
535 static const struct backlight_ops ssd1307fb_bl_ops = {
536 	.options	= BL_CORE_SUSPENDRESUME,
537 	.update_status	= ssd1307fb_update_bl,
538 	.get_brightness	= ssd1307fb_get_brightness,
539 	.check_fb	= ssd1307fb_check_fb,
540 };
541 
542 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1305_deviceinfo = {
543 	.default_vcomh = 0x34,
544 	.default_dclk_div = 1,
545 	.default_dclk_frq = 7,
546 };
547 
548 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1306_deviceinfo = {
549 	.default_vcomh = 0x20,
550 	.default_dclk_div = 1,
551 	.default_dclk_frq = 8,
552 	.need_chargepump = 1,
553 };
554 
555 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1307_deviceinfo = {
556 	.default_vcomh = 0x20,
557 	.default_dclk_div = 2,
558 	.default_dclk_frq = 12,
559 	.need_pwm = 1,
560 };
561 
562 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1309_deviceinfo = {
563 	.default_vcomh = 0x34,
564 	.default_dclk_div = 1,
565 	.default_dclk_frq = 10,
566 };
567 
568 static const struct of_device_id ssd1307fb_of_match[] = {
569 	{
570 		.compatible = "solomon,ssd1305fb-i2c",
571 		.data = (void *)&ssd1307fb_ssd1305_deviceinfo,
572 	},
573 	{
574 		.compatible = "solomon,ssd1306fb-i2c",
575 		.data = (void *)&ssd1307fb_ssd1306_deviceinfo,
576 	},
577 	{
578 		.compatible = "solomon,ssd1307fb-i2c",
579 		.data = (void *)&ssd1307fb_ssd1307_deviceinfo,
580 	},
581 	{
582 		.compatible = "solomon,ssd1309fb-i2c",
583 		.data = (void *)&ssd1307fb_ssd1309_deviceinfo,
584 	},
585 	{},
586 };
587 MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
588 
589 static int ssd1307fb_probe(struct i2c_client *client,
590 			   const struct i2c_device_id *id)
591 {
592 	struct backlight_device *bl;
593 	char bl_name[12];
594 	struct fb_info *info;
595 	struct device_node *node = client->dev.of_node;
596 	struct fb_deferred_io *ssd1307fb_defio;
597 	u32 vmem_size;
598 	struct ssd1307fb_par *par;
599 	void *vmem;
600 	int ret;
601 
602 	if (!node) {
603 		dev_err(&client->dev, "No device tree data found!\n");
604 		return -EINVAL;
605 	}
606 
607 	info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev);
608 	if (!info)
609 		return -ENOMEM;
610 
611 	par = info->par;
612 	par->info = info;
613 	par->client = client;
614 
615 	par->device_info = of_device_get_match_data(&client->dev);
616 
617 	par->reset = devm_gpiod_get_optional(&client->dev, "reset",
618 					     GPIOD_OUT_LOW);
619 	if (IS_ERR(par->reset)) {
620 		dev_err(&client->dev, "failed to get reset gpio: %ld\n",
621 			PTR_ERR(par->reset));
622 		ret = PTR_ERR(par->reset);
623 		goto fb_alloc_error;
624 	}
625 
626 	par->vbat_reg = devm_regulator_get_optional(&client->dev, "vbat");
627 	if (IS_ERR(par->vbat_reg)) {
628 		ret = PTR_ERR(par->vbat_reg);
629 		if (ret == -ENODEV) {
630 			par->vbat_reg = NULL;
631 		} else {
632 			dev_err(&client->dev, "failed to get VBAT regulator: %d\n",
633 				ret);
634 			goto fb_alloc_error;
635 		}
636 	}
637 
638 	if (of_property_read_u32(node, "solomon,width", &par->width))
639 		par->width = 96;
640 
641 	if (of_property_read_u32(node, "solomon,height", &par->height))
642 		par->height = 16;
643 
644 	if (of_property_read_u32(node, "solomon,page-offset", &par->page_offset))
645 		par->page_offset = 1;
646 
647 	if (of_property_read_u32(node, "solomon,com-offset", &par->com_offset))
648 		par->com_offset = 0;
649 
650 	if (of_property_read_u32(node, "solomon,prechargep1", &par->prechargep1))
651 		par->prechargep1 = 2;
652 
653 	if (of_property_read_u32(node, "solomon,prechargep2", &par->prechargep2))
654 		par->prechargep2 = 2;
655 
656 	if (!of_property_read_u8_array(node, "solomon,lookup-table",
657 				       par->lookup_table,
658 				       ARRAY_SIZE(par->lookup_table)))
659 		par->lookup_table_set = 1;
660 
661 	par->seg_remap = !of_property_read_bool(node, "solomon,segment-no-remap");
662 	par->com_seq = of_property_read_bool(node, "solomon,com-seq");
663 	par->com_lrremap = of_property_read_bool(node, "solomon,com-lrremap");
664 	par->com_invdir = of_property_read_bool(node, "solomon,com-invdir");
665 	par->area_color_enable =
666 		of_property_read_bool(node, "solomon,area-color-enable");
667 	par->low_power = of_property_read_bool(node, "solomon,low-power");
668 
669 	par->contrast = 127;
670 	par->vcomh = par->device_info->default_vcomh;
671 
672 	/* Setup display timing */
673 	if (of_property_read_u32(node, "solomon,dclk-div", &par->dclk_div))
674 		par->dclk_div = par->device_info->default_dclk_div;
675 	if (of_property_read_u32(node, "solomon,dclk-frq", &par->dclk_frq))
676 		par->dclk_frq = par->device_info->default_dclk_frq;
677 
678 	vmem_size = DIV_ROUND_UP(par->width, 8) * par->height;
679 
680 	vmem = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
681 					get_order(vmem_size));
682 	if (!vmem) {
683 		dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
684 		ret = -ENOMEM;
685 		goto fb_alloc_error;
686 	}
687 
688 	ssd1307fb_defio = devm_kzalloc(&client->dev, sizeof(*ssd1307fb_defio),
689 				       GFP_KERNEL);
690 	if (!ssd1307fb_defio) {
691 		dev_err(&client->dev, "Couldn't allocate deferred io.\n");
692 		ret = -ENOMEM;
693 		goto fb_alloc_error;
694 	}
695 
696 	ssd1307fb_defio->delay = HZ / refreshrate;
697 	ssd1307fb_defio->deferred_io = ssd1307fb_deferred_io;
698 
699 	info->fbops = &ssd1307fb_ops;
700 	info->fix = ssd1307fb_fix;
701 	info->fix.line_length = DIV_ROUND_UP(par->width, 8);
702 	info->fbdefio = ssd1307fb_defio;
703 
704 	info->var = ssd1307fb_var;
705 	info->var.xres = par->width;
706 	info->var.xres_virtual = par->width;
707 	info->var.yres = par->height;
708 	info->var.yres_virtual = par->height;
709 
710 	info->screen_buffer = vmem;
711 	info->fix.smem_start = __pa(vmem);
712 	info->fix.smem_len = vmem_size;
713 
714 	fb_deferred_io_init(info);
715 
716 	i2c_set_clientdata(client, info);
717 
718 	if (par->reset) {
719 		/* Reset the screen */
720 		gpiod_set_value_cansleep(par->reset, 1);
721 		udelay(4);
722 		gpiod_set_value_cansleep(par->reset, 0);
723 		udelay(4);
724 	}
725 
726 	if (par->vbat_reg) {
727 		ret = regulator_enable(par->vbat_reg);
728 		if (ret) {
729 			dev_err(&client->dev, "failed to enable VBAT: %d\n",
730 				ret);
731 			goto reset_oled_error;
732 		}
733 	}
734 
735 	ret = ssd1307fb_init(par);
736 	if (ret)
737 		goto regulator_enable_error;
738 
739 	ret = register_framebuffer(info);
740 	if (ret) {
741 		dev_err(&client->dev, "Couldn't register the framebuffer\n");
742 		goto panel_init_error;
743 	}
744 
745 	snprintf(bl_name, sizeof(bl_name), "ssd1307fb%d", info->node);
746 	bl = backlight_device_register(bl_name, &client->dev, par,
747 				       &ssd1307fb_bl_ops, NULL);
748 	if (IS_ERR(bl)) {
749 		ret = PTR_ERR(bl);
750 		dev_err(&client->dev, "unable to register backlight device: %d\n",
751 			ret);
752 		goto bl_init_error;
753 	}
754 
755 	bl->props.brightness = par->contrast;
756 	bl->props.max_brightness = MAX_CONTRAST;
757 	info->bl_dev = bl;
758 
759 	dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
760 
761 	return 0;
762 
763 bl_init_error:
764 	unregister_framebuffer(info);
765 panel_init_error:
766 	if (par->device_info->need_pwm) {
767 		pwm_disable(par->pwm);
768 		pwm_put(par->pwm);
769 	}
770 regulator_enable_error:
771 	if (par->vbat_reg)
772 		regulator_disable(par->vbat_reg);
773 reset_oled_error:
774 	fb_deferred_io_cleanup(info);
775 fb_alloc_error:
776 	framebuffer_release(info);
777 	return ret;
778 }
779 
780 static int ssd1307fb_remove(struct i2c_client *client)
781 {
782 	struct fb_info *info = i2c_get_clientdata(client);
783 	struct ssd1307fb_par *par = info->par;
784 
785 	ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
786 
787 	backlight_device_unregister(info->bl_dev);
788 
789 	unregister_framebuffer(info);
790 	if (par->device_info->need_pwm) {
791 		pwm_disable(par->pwm);
792 		pwm_put(par->pwm);
793 	}
794 	fb_deferred_io_cleanup(info);
795 	__free_pages(__va(info->fix.smem_start), get_order(info->fix.smem_len));
796 	framebuffer_release(info);
797 
798 	return 0;
799 }
800 
801 static const struct i2c_device_id ssd1307fb_i2c_id[] = {
802 	{ "ssd1305fb", 0 },
803 	{ "ssd1306fb", 0 },
804 	{ "ssd1307fb", 0 },
805 	{ "ssd1309fb", 0 },
806 	{ }
807 };
808 MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id);
809 
810 static struct i2c_driver ssd1307fb_driver = {
811 	.probe = ssd1307fb_probe,
812 	.remove = ssd1307fb_remove,
813 	.id_table = ssd1307fb_i2c_id,
814 	.driver = {
815 		.name = "ssd1307fb",
816 		.of_match_table = ssd1307fb_of_match,
817 	},
818 };
819 
820 module_i2c_driver(ssd1307fb_driver);
821 
822 MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controller");
823 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
824 MODULE_LICENSE("GPL");
825