xref: /linux/drivers/video/fbdev/ssd1307fb.c (revision f3a8b6645dc2e60d11f20c1c23afd964ff4e55ae)
1 /*
2  * Driver for the Solomon SSD1307 OLED controller
3  *
4  * Copyright 2012 Free Electrons
5  *
6  * Licensed under the GPLv2 or later.
7  */
8 
9 #include <linux/backlight.h>
10 #include <linux/delay.h>
11 #include <linux/fb.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 
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_CHARGE_PUMP		0x8d
31 #define SSD1307FB_SEG_REMAP_ON		0xa1
32 #define SSD1307FB_DISPLAY_OFF		0xae
33 #define SSD1307FB_SET_MULTIPLEX_RATIO	0xa8
34 #define SSD1307FB_DISPLAY_ON		0xaf
35 #define SSD1307FB_START_PAGE_ADDRESS	0xb0
36 #define SSD1307FB_SET_DISPLAY_OFFSET	0xd3
37 #define	SSD1307FB_SET_CLOCK_FREQ	0xd5
38 #define	SSD1307FB_SET_PRECHARGE_PERIOD	0xd9
39 #define	SSD1307FB_SET_COM_PINS_CONFIG	0xda
40 #define	SSD1307FB_SET_VCOMH		0xdb
41 
42 #define MAX_CONTRAST 255
43 
44 #define REFRESHRATE 1
45 
46 static u_int refreshrate = REFRESHRATE;
47 module_param(refreshrate, uint, 0);
48 
49 struct ssd1307fb_par;
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 	u32 com_invdir;
61 	u32 com_lrremap;
62 	u32 com_offset;
63 	u32 com_seq;
64 	u32 contrast;
65 	u32 dclk_div;
66 	u32 dclk_frq;
67 	const struct ssd1307fb_deviceinfo *device_info;
68 	struct i2c_client *client;
69 	u32 height;
70 	struct fb_info *info;
71 	u32 page_offset;
72 	u32 prechargep1;
73 	u32 prechargep2;
74 	struct pwm_device *pwm;
75 	u32 pwm_period;
76 	int reset;
77 	u32 seg_remap;
78 	u32 vcomh;
79 	u32 width;
80 };
81 
82 struct ssd1307fb_array {
83 	u8	type;
84 	u8	data[0];
85 };
86 
87 static const struct fb_fix_screeninfo ssd1307fb_fix = {
88 	.id		= "Solomon SSD1307",
89 	.type		= FB_TYPE_PACKED_PIXELS,
90 	.visual		= FB_VISUAL_MONO10,
91 	.xpanstep	= 0,
92 	.ypanstep	= 0,
93 	.ywrapstep	= 0,
94 	.accel		= FB_ACCEL_NONE,
95 };
96 
97 static const struct fb_var_screeninfo ssd1307fb_var = {
98 	.bits_per_pixel	= 1,
99 };
100 
101 static struct ssd1307fb_array *ssd1307fb_alloc_array(u32 len, u8 type)
102 {
103 	struct ssd1307fb_array *array;
104 
105 	array = kzalloc(sizeof(struct ssd1307fb_array) + len, GFP_KERNEL);
106 	if (!array)
107 		return NULL;
108 
109 	array->type = type;
110 
111 	return array;
112 }
113 
114 static int ssd1307fb_write_array(struct i2c_client *client,
115 				 struct ssd1307fb_array *array, u32 len)
116 {
117 	int ret;
118 
119 	len += sizeof(struct ssd1307fb_array);
120 
121 	ret = i2c_master_send(client, (u8 *)array, len);
122 	if (ret != len) {
123 		dev_err(&client->dev, "Couldn't send I2C command.\n");
124 		return ret;
125 	}
126 
127 	return 0;
128 }
129 
130 static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
131 {
132 	struct ssd1307fb_array *array;
133 	int ret;
134 
135 	array = ssd1307fb_alloc_array(1, SSD1307FB_COMMAND);
136 	if (!array)
137 		return -ENOMEM;
138 
139 	array->data[0] = cmd;
140 
141 	ret = ssd1307fb_write_array(client, array, 1);
142 	kfree(array);
143 
144 	return ret;
145 }
146 
147 static void ssd1307fb_update_display(struct ssd1307fb_par *par)
148 {
149 	struct ssd1307fb_array *array;
150 	u8 *vmem = par->info->screen_base;
151 	int i, j, k;
152 
153 	array = ssd1307fb_alloc_array(par->width * par->height / 8,
154 				      SSD1307FB_DATA);
155 	if (!array)
156 		return;
157 
158 	/*
159 	 * The screen is divided in pages, each having a height of 8
160 	 * pixels, and the width of the screen. When sending a byte of
161 	 * data to the controller, it gives the 8 bits for the current
162 	 * column. I.e, the first byte are the 8 bits of the first
163 	 * column, then the 8 bits for the second column, etc.
164 	 *
165 	 *
166 	 * Representation of the screen, assuming it is 5 bits
167 	 * wide. Each letter-number combination is a bit that controls
168 	 * one pixel.
169 	 *
170 	 * A0 A1 A2 A3 A4
171 	 * B0 B1 B2 B3 B4
172 	 * C0 C1 C2 C3 C4
173 	 * D0 D1 D2 D3 D4
174 	 * E0 E1 E2 E3 E4
175 	 * F0 F1 F2 F3 F4
176 	 * G0 G1 G2 G3 G4
177 	 * H0 H1 H2 H3 H4
178 	 *
179 	 * If you want to update this screen, you need to send 5 bytes:
180 	 *  (1) A0 B0 C0 D0 E0 F0 G0 H0
181 	 *  (2) A1 B1 C1 D1 E1 F1 G1 H1
182 	 *  (3) A2 B2 C2 D2 E2 F2 G2 H2
183 	 *  (4) A3 B3 C3 D3 E3 F3 G3 H3
184 	 *  (5) A4 B4 C4 D4 E4 F4 G4 H4
185 	 */
186 
187 	for (i = 0; i < (par->height / 8); i++) {
188 		for (j = 0; j < par->width; j++) {
189 			u32 array_idx = i * par->width + j;
190 			array->data[array_idx] = 0;
191 			for (k = 0; k < 8; k++) {
192 				u32 page_length = par->width * i;
193 				u32 index = page_length + (par->width * k + j) / 8;
194 				u8 byte = *(vmem + index);
195 				u8 bit = byte & (1 << (j % 8));
196 				bit = bit >> (j % 8);
197 				array->data[array_idx] |= bit << k;
198 			}
199 		}
200 	}
201 
202 	ssd1307fb_write_array(par->client, array, par->width * par->height / 8);
203 	kfree(array);
204 }
205 
206 
207 static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
208 		size_t count, loff_t *ppos)
209 {
210 	struct ssd1307fb_par *par = info->par;
211 	unsigned long total_size;
212 	unsigned long p = *ppos;
213 	u8 __iomem *dst;
214 
215 	total_size = info->fix.smem_len;
216 
217 	if (p > total_size)
218 		return -EINVAL;
219 
220 	if (count + p > total_size)
221 		count = total_size - p;
222 
223 	if (!count)
224 		return -EINVAL;
225 
226 	dst = (void __force *) (info->screen_base + p);
227 
228 	if (copy_from_user(dst, buf, count))
229 		return -EFAULT;
230 
231 	ssd1307fb_update_display(par);
232 
233 	*ppos += count;
234 
235 	return count;
236 }
237 
238 static int ssd1307fb_blank(int blank_mode, struct fb_info *info)
239 {
240 	struct ssd1307fb_par *par = info->par;
241 
242 	if (blank_mode != FB_BLANK_UNBLANK)
243 		return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
244 	else
245 		return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
246 }
247 
248 static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
249 {
250 	struct ssd1307fb_par *par = info->par;
251 	sys_fillrect(info, rect);
252 	ssd1307fb_update_display(par);
253 }
254 
255 static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
256 {
257 	struct ssd1307fb_par *par = info->par;
258 	sys_copyarea(info, area);
259 	ssd1307fb_update_display(par);
260 }
261 
262 static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image)
263 {
264 	struct ssd1307fb_par *par = info->par;
265 	sys_imageblit(info, image);
266 	ssd1307fb_update_display(par);
267 }
268 
269 static struct fb_ops ssd1307fb_ops = {
270 	.owner		= THIS_MODULE,
271 	.fb_read	= fb_sys_read,
272 	.fb_write	= ssd1307fb_write,
273 	.fb_blank	= ssd1307fb_blank,
274 	.fb_fillrect	= ssd1307fb_fillrect,
275 	.fb_copyarea	= ssd1307fb_copyarea,
276 	.fb_imageblit	= ssd1307fb_imageblit,
277 };
278 
279 static void ssd1307fb_deferred_io(struct fb_info *info,
280 				struct list_head *pagelist)
281 {
282 	ssd1307fb_update_display(info->par);
283 }
284 
285 static int ssd1307fb_init(struct ssd1307fb_par *par)
286 {
287 	int ret;
288 	u32 precharge, dclk, com_invdir, compins;
289 	struct pwm_args pargs;
290 
291 	if (par->device_info->need_pwm) {
292 		par->pwm = pwm_get(&par->client->dev, NULL);
293 		if (IS_ERR(par->pwm)) {
294 			dev_err(&par->client->dev, "Could not get PWM from device tree!\n");
295 			return PTR_ERR(par->pwm);
296 		}
297 
298 		/*
299 		 * FIXME: pwm_apply_args() should be removed when switching to
300 		 * the atomic PWM API.
301 		 */
302 		pwm_apply_args(par->pwm);
303 
304 		pwm_get_args(par->pwm, &pargs);
305 
306 		par->pwm_period = pargs.period;
307 		/* Enable the PWM */
308 		pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
309 		pwm_enable(par->pwm);
310 
311 		dev_dbg(&par->client->dev, "Using PWM%d with a %dns period.\n",
312 			par->pwm->pwm, par->pwm_period);
313 	};
314 
315 	/* Set initial contrast */
316 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
317 	if (ret < 0)
318 		return ret;
319 
320 	ret = ssd1307fb_write_cmd(par->client, par->contrast);
321 	if (ret < 0)
322 		return ret;
323 
324 	/* Set segment re-map */
325 	if (par->seg_remap) {
326 		ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
327 		if (ret < 0)
328 			return ret;
329 	};
330 
331 	/* Set COM direction */
332 	com_invdir = 0xc0 | (par->com_invdir & 0x1) << 3;
333 	ret = ssd1307fb_write_cmd(par->client,  com_invdir);
334 	if (ret < 0)
335 		return ret;
336 
337 	/* Set multiplex ratio value */
338 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO);
339 	if (ret < 0)
340 		return ret;
341 
342 	ret = ssd1307fb_write_cmd(par->client, par->height - 1);
343 	if (ret < 0)
344 		return ret;
345 
346 	/* set display offset value */
347 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET);
348 	if (ret < 0)
349 		return ret;
350 
351 	ret = ssd1307fb_write_cmd(par->client, par->com_offset);
352 	if (ret < 0)
353 		return ret;
354 
355 	/* Set clock frequency */
356 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ);
357 	if (ret < 0)
358 		return ret;
359 
360 	dclk = ((par->dclk_div - 1) & 0xf) | (par->dclk_frq & 0xf) << 4;
361 	ret = ssd1307fb_write_cmd(par->client, dclk);
362 	if (ret < 0)
363 		return ret;
364 
365 	/* Set precharge period in number of ticks from the internal clock */
366 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD);
367 	if (ret < 0)
368 		return ret;
369 
370 	precharge = (par->prechargep1 & 0xf) | (par->prechargep2 & 0xf) << 4;
371 	ret = ssd1307fb_write_cmd(par->client, precharge);
372 	if (ret < 0)
373 		return ret;
374 
375 	/* Set COM pins configuration */
376 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG);
377 	if (ret < 0)
378 		return ret;
379 
380 	compins = 0x02 | !(par->com_seq & 0x1) << 4
381 				   | (par->com_lrremap & 0x1) << 5;
382 	ret = ssd1307fb_write_cmd(par->client, compins);
383 	if (ret < 0)
384 		return ret;
385 
386 	/* Set VCOMH */
387 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH);
388 	if (ret < 0)
389 		return ret;
390 
391 	ret = ssd1307fb_write_cmd(par->client, par->vcomh);
392 	if (ret < 0)
393 		return ret;
394 
395 	/* Turn on the DC-DC Charge Pump */
396 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
397 	if (ret < 0)
398 		return ret;
399 
400 	ret = ssd1307fb_write_cmd(par->client,
401 		BIT(4) | (par->device_info->need_chargepump ? BIT(2) : 0));
402 	if (ret < 0)
403 		return ret;
404 
405 	/* Switch to horizontal addressing mode */
406 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_ADDRESS_MODE);
407 	if (ret < 0)
408 		return ret;
409 
410 	ret = ssd1307fb_write_cmd(par->client,
411 				  SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL);
412 	if (ret < 0)
413 		return ret;
414 
415 	/* Set column range */
416 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
417 	if (ret < 0)
418 		return ret;
419 
420 	ret = ssd1307fb_write_cmd(par->client, 0x0);
421 	if (ret < 0)
422 		return ret;
423 
424 	ret = ssd1307fb_write_cmd(par->client, par->width - 1);
425 	if (ret < 0)
426 		return ret;
427 
428 	/* Set page range */
429 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
430 	if (ret < 0)
431 		return ret;
432 
433 	ret = ssd1307fb_write_cmd(par->client, 0x0);
434 	if (ret < 0)
435 		return ret;
436 
437 	ret = ssd1307fb_write_cmd(par->client,
438 				  par->page_offset + (par->height / 8) - 1);
439 	if (ret < 0)
440 		return ret;
441 
442 	/* Turn on the display */
443 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
444 	if (ret < 0)
445 		return ret;
446 
447 	return 0;
448 }
449 
450 static int ssd1307fb_update_bl(struct backlight_device *bdev)
451 {
452 	struct ssd1307fb_par *par = bl_get_data(bdev);
453 	int ret;
454 	int brightness = bdev->props.brightness;
455 
456 	par->contrast = brightness;
457 
458 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
459 	if (ret < 0)
460 		return ret;
461 	ret = ssd1307fb_write_cmd(par->client, par->contrast);
462 	if (ret < 0)
463 		return ret;
464 	return 0;
465 }
466 
467 static int ssd1307fb_get_brightness(struct backlight_device *bdev)
468 {
469 	struct ssd1307fb_par *par = bl_get_data(bdev);
470 
471 	return par->contrast;
472 }
473 
474 static int ssd1307fb_check_fb(struct backlight_device *bdev,
475 				   struct fb_info *info)
476 {
477 	return (info->bl_dev == bdev);
478 }
479 
480 static const struct backlight_ops ssd1307fb_bl_ops = {
481 	.options	= BL_CORE_SUSPENDRESUME,
482 	.update_status	= ssd1307fb_update_bl,
483 	.get_brightness	= ssd1307fb_get_brightness,
484 	.check_fb	= ssd1307fb_check_fb,
485 };
486 
487 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1305_deviceinfo = {
488 	.default_vcomh = 0x34,
489 	.default_dclk_div = 1,
490 	.default_dclk_frq = 7,
491 };
492 
493 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1306_deviceinfo = {
494 	.default_vcomh = 0x20,
495 	.default_dclk_div = 1,
496 	.default_dclk_frq = 8,
497 	.need_chargepump = 1,
498 };
499 
500 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1307_deviceinfo = {
501 	.default_vcomh = 0x20,
502 	.default_dclk_div = 2,
503 	.default_dclk_frq = 12,
504 	.need_pwm = 1,
505 };
506 
507 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1309_deviceinfo = {
508 	.default_vcomh = 0x34,
509 	.default_dclk_div = 1,
510 	.default_dclk_frq = 10,
511 };
512 
513 static const struct of_device_id ssd1307fb_of_match[] = {
514 	{
515 		.compatible = "solomon,ssd1305fb-i2c",
516 		.data = (void *)&ssd1307fb_ssd1305_deviceinfo,
517 	},
518 	{
519 		.compatible = "solomon,ssd1306fb-i2c",
520 		.data = (void *)&ssd1307fb_ssd1306_deviceinfo,
521 	},
522 	{
523 		.compatible = "solomon,ssd1307fb-i2c",
524 		.data = (void *)&ssd1307fb_ssd1307_deviceinfo,
525 	},
526 	{
527 		.compatible = "solomon,ssd1309fb-i2c",
528 		.data = (void *)&ssd1307fb_ssd1309_deviceinfo,
529 	},
530 	{},
531 };
532 MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
533 
534 static int ssd1307fb_probe(struct i2c_client *client,
535 			   const struct i2c_device_id *id)
536 {
537 	struct backlight_device *bl;
538 	char bl_name[12];
539 	struct fb_info *info;
540 	struct device_node *node = client->dev.of_node;
541 	struct fb_deferred_io *ssd1307fb_defio;
542 	u32 vmem_size;
543 	struct ssd1307fb_par *par;
544 	u8 *vmem;
545 	int ret;
546 
547 	if (!node) {
548 		dev_err(&client->dev, "No device tree data found!\n");
549 		return -EINVAL;
550 	}
551 
552 	info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev);
553 	if (!info) {
554 		dev_err(&client->dev, "Couldn't allocate framebuffer.\n");
555 		return -ENOMEM;
556 	}
557 
558 	par = info->par;
559 	par->info = info;
560 	par->client = client;
561 
562 	par->device_info = of_device_get_match_data(&client->dev);
563 
564 	par->reset = of_get_named_gpio(client->dev.of_node,
565 					 "reset-gpios", 0);
566 	if (!gpio_is_valid(par->reset)) {
567 		ret = -EINVAL;
568 		goto fb_alloc_error;
569 	}
570 
571 	if (of_property_read_u32(node, "solomon,width", &par->width))
572 		par->width = 96;
573 
574 	if (of_property_read_u32(node, "solomon,height", &par->height))
575 		par->height = 16;
576 
577 	if (of_property_read_u32(node, "solomon,page-offset", &par->page_offset))
578 		par->page_offset = 1;
579 
580 	if (of_property_read_u32(node, "solomon,com-offset", &par->com_offset))
581 		par->com_offset = 0;
582 
583 	if (of_property_read_u32(node, "solomon,prechargep1", &par->prechargep1))
584 		par->prechargep1 = 2;
585 
586 	if (of_property_read_u32(node, "solomon,prechargep2", &par->prechargep2))
587 		par->prechargep2 = 2;
588 
589 	par->seg_remap = !of_property_read_bool(node, "solomon,segment-no-remap");
590 	par->com_seq = of_property_read_bool(node, "solomon,com-seq");
591 	par->com_lrremap = of_property_read_bool(node, "solomon,com-lrremap");
592 	par->com_invdir = of_property_read_bool(node, "solomon,com-invdir");
593 
594 	par->contrast = 127;
595 	par->vcomh = par->device_info->default_vcomh;
596 
597 	/* Setup display timing */
598 	par->dclk_div = par->device_info->default_dclk_div;
599 	par->dclk_frq = par->device_info->default_dclk_frq;
600 
601 	vmem_size = par->width * par->height / 8;
602 
603 	vmem = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
604 					get_order(vmem_size));
605 	if (!vmem) {
606 		dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
607 		ret = -ENOMEM;
608 		goto fb_alloc_error;
609 	}
610 
611 	ssd1307fb_defio = devm_kzalloc(&client->dev, sizeof(struct fb_deferred_io), GFP_KERNEL);
612 	if (!ssd1307fb_defio) {
613 		dev_err(&client->dev, "Couldn't allocate deferred io.\n");
614 		ret = -ENOMEM;
615 		goto fb_alloc_error;
616 	}
617 
618 	ssd1307fb_defio->delay = HZ / refreshrate;
619 	ssd1307fb_defio->deferred_io = ssd1307fb_deferred_io;
620 
621 	info->fbops = &ssd1307fb_ops;
622 	info->fix = ssd1307fb_fix;
623 	info->fix.line_length = par->width / 8;
624 	info->fbdefio = ssd1307fb_defio;
625 
626 	info->var = ssd1307fb_var;
627 	info->var.xres = par->width;
628 	info->var.xres_virtual = par->width;
629 	info->var.yres = par->height;
630 	info->var.yres_virtual = par->height;
631 
632 	info->var.red.length = 1;
633 	info->var.red.offset = 0;
634 	info->var.green.length = 1;
635 	info->var.green.offset = 0;
636 	info->var.blue.length = 1;
637 	info->var.blue.offset = 0;
638 
639 	info->screen_base = (u8 __force __iomem *)vmem;
640 	info->fix.smem_start = __pa(vmem);
641 	info->fix.smem_len = vmem_size;
642 
643 	fb_deferred_io_init(info);
644 
645 	ret = devm_gpio_request_one(&client->dev, par->reset,
646 				    GPIOF_OUT_INIT_HIGH,
647 				    "oled-reset");
648 	if (ret) {
649 		dev_err(&client->dev,
650 			"failed to request gpio %d: %d\n",
651 			par->reset, ret);
652 		goto reset_oled_error;
653 	}
654 
655 	i2c_set_clientdata(client, info);
656 
657 	/* Reset the screen */
658 	gpio_set_value(par->reset, 0);
659 	udelay(4);
660 	gpio_set_value(par->reset, 1);
661 	udelay(4);
662 
663 	ret = ssd1307fb_init(par);
664 	if (ret)
665 		goto reset_oled_error;
666 
667 	ret = register_framebuffer(info);
668 	if (ret) {
669 		dev_err(&client->dev, "Couldn't register the framebuffer\n");
670 		goto panel_init_error;
671 	}
672 
673 	snprintf(bl_name, sizeof(bl_name), "ssd1307fb%d", info->node);
674 	bl = backlight_device_register(bl_name, &client->dev, par,
675 				       &ssd1307fb_bl_ops, NULL);
676 	if (IS_ERR(bl)) {
677 		ret = PTR_ERR(bl);
678 		dev_err(&client->dev, "unable to register backlight device: %d\n",
679 			ret);
680 		goto bl_init_error;
681 	}
682 
683 	bl->props.brightness = par->contrast;
684 	bl->props.max_brightness = MAX_CONTRAST;
685 	info->bl_dev = bl;
686 
687 	dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
688 
689 	return 0;
690 
691 bl_init_error:
692 	unregister_framebuffer(info);
693 panel_init_error:
694 	if (par->device_info->need_pwm) {
695 		pwm_disable(par->pwm);
696 		pwm_put(par->pwm);
697 	};
698 reset_oled_error:
699 	fb_deferred_io_cleanup(info);
700 fb_alloc_error:
701 	framebuffer_release(info);
702 	return ret;
703 }
704 
705 static int ssd1307fb_remove(struct i2c_client *client)
706 {
707 	struct fb_info *info = i2c_get_clientdata(client);
708 	struct ssd1307fb_par *par = info->par;
709 
710 	ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
711 
712 	backlight_device_unregister(info->bl_dev);
713 
714 	unregister_framebuffer(info);
715 	if (par->device_info->need_pwm) {
716 		pwm_disable(par->pwm);
717 		pwm_put(par->pwm);
718 	};
719 	fb_deferred_io_cleanup(info);
720 	__free_pages(__va(info->fix.smem_start), get_order(info->fix.smem_len));
721 	framebuffer_release(info);
722 
723 	return 0;
724 }
725 
726 static const struct i2c_device_id ssd1307fb_i2c_id[] = {
727 	{ "ssd1305fb", 0 },
728 	{ "ssd1306fb", 0 },
729 	{ "ssd1307fb", 0 },
730 	{ "ssd1309fb", 0 },
731 	{ }
732 };
733 MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id);
734 
735 static struct i2c_driver ssd1307fb_driver = {
736 	.probe = ssd1307fb_probe,
737 	.remove = ssd1307fb_remove,
738 	.id_table = ssd1307fb_i2c_id,
739 	.driver = {
740 		.name = "ssd1307fb",
741 		.of_match_table = ssd1307fb_of_match,
742 	},
743 };
744 
745 module_i2c_driver(ssd1307fb_driver);
746 
747 MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controller");
748 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
749 MODULE_LICENSE("GPL");
750