xref: /openbmc/linux/drivers/video/fbdev/ssd1307fb.c (revision 9fb29c73)
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/gpio/consumer.h>
13 #include <linux/i2c.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/of_device.h>
17 #include <linux/of_gpio.h>
18 #include <linux/pwm.h>
19 #include <linux/uaccess.h>
20 #include <linux/regulator/consumer.h>
21 
22 #define SSD1307FB_DATA			0x40
23 #define SSD1307FB_COMMAND		0x80
24 
25 #define SSD1307FB_SET_ADDRESS_MODE	0x20
26 #define SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL	(0x00)
27 #define SSD1307FB_SET_ADDRESS_MODE_VERTICAL	(0x01)
28 #define SSD1307FB_SET_ADDRESS_MODE_PAGE		(0x02)
29 #define SSD1307FB_SET_COL_RANGE		0x21
30 #define SSD1307FB_SET_PAGE_RANGE	0x22
31 #define SSD1307FB_CONTRAST		0x81
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_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_par;
52 
53 struct ssd1307fb_deviceinfo {
54 	u32 default_vcomh;
55 	u32 default_dclk_div;
56 	u32 default_dclk_frq;
57 	int need_pwm;
58 	int need_chargepump;
59 };
60 
61 struct ssd1307fb_par {
62 	u32 com_invdir;
63 	u32 com_lrremap;
64 	u32 com_offset;
65 	u32 com_seq;
66 	u32 contrast;
67 	u32 dclk_div;
68 	u32 dclk_frq;
69 	const struct ssd1307fb_deviceinfo *device_info;
70 	struct i2c_client *client;
71 	u32 height;
72 	struct fb_info *info;
73 	u32 page_offset;
74 	u32 prechargep1;
75 	u32 prechargep2;
76 	struct pwm_device *pwm;
77 	u32 pwm_period;
78 	struct gpio_desc *reset;
79 	struct regulator *vbat_reg;
80 	u32 seg_remap;
81 	u32 vcomh;
82 	u32 width;
83 };
84 
85 struct ssd1307fb_array {
86 	u8	type;
87 	u8	data[0];
88 };
89 
90 static const struct fb_fix_screeninfo ssd1307fb_fix = {
91 	.id		= "Solomon SSD1307",
92 	.type		= FB_TYPE_PACKED_PIXELS,
93 	.visual		= FB_VISUAL_MONO10,
94 	.xpanstep	= 0,
95 	.ypanstep	= 0,
96 	.ywrapstep	= 0,
97 	.accel		= FB_ACCEL_NONE,
98 };
99 
100 static const struct fb_var_screeninfo ssd1307fb_var = {
101 	.bits_per_pixel	= 1,
102 };
103 
104 static struct ssd1307fb_array *ssd1307fb_alloc_array(u32 len, u8 type)
105 {
106 	struct ssd1307fb_array *array;
107 
108 	array = kzalloc(sizeof(struct ssd1307fb_array) + len, GFP_KERNEL);
109 	if (!array)
110 		return NULL;
111 
112 	array->type = type;
113 
114 	return array;
115 }
116 
117 static int ssd1307fb_write_array(struct i2c_client *client,
118 				 struct ssd1307fb_array *array, u32 len)
119 {
120 	int ret;
121 
122 	len += sizeof(struct ssd1307fb_array);
123 
124 	ret = i2c_master_send(client, (u8 *)array, len);
125 	if (ret != len) {
126 		dev_err(&client->dev, "Couldn't send I2C command.\n");
127 		return ret;
128 	}
129 
130 	return 0;
131 }
132 
133 static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
134 {
135 	struct ssd1307fb_array *array;
136 	int ret;
137 
138 	array = ssd1307fb_alloc_array(1, SSD1307FB_COMMAND);
139 	if (!array)
140 		return -ENOMEM;
141 
142 	array->data[0] = cmd;
143 
144 	ret = ssd1307fb_write_array(client, array, 1);
145 	kfree(array);
146 
147 	return ret;
148 }
149 
150 static void ssd1307fb_update_display(struct ssd1307fb_par *par)
151 {
152 	struct ssd1307fb_array *array;
153 	u8 *vmem = par->info->screen_base;
154 	int i, j, k;
155 
156 	array = ssd1307fb_alloc_array(par->width * par->height / 8,
157 				      SSD1307FB_DATA);
158 	if (!array)
159 		return;
160 
161 	/*
162 	 * The screen is divided in pages, each having a height of 8
163 	 * pixels, and the width of the screen. When sending a byte of
164 	 * data to the controller, it gives the 8 bits for the current
165 	 * column. I.e, the first byte are the 8 bits of the first
166 	 * column, then the 8 bits for the second column, etc.
167 	 *
168 	 *
169 	 * Representation of the screen, assuming it is 5 bits
170 	 * wide. Each letter-number combination is a bit that controls
171 	 * one pixel.
172 	 *
173 	 * A0 A1 A2 A3 A4
174 	 * B0 B1 B2 B3 B4
175 	 * C0 C1 C2 C3 C4
176 	 * D0 D1 D2 D3 D4
177 	 * E0 E1 E2 E3 E4
178 	 * F0 F1 F2 F3 F4
179 	 * G0 G1 G2 G3 G4
180 	 * H0 H1 H2 H3 H4
181 	 *
182 	 * If you want to update this screen, you need to send 5 bytes:
183 	 *  (1) A0 B0 C0 D0 E0 F0 G0 H0
184 	 *  (2) A1 B1 C1 D1 E1 F1 G1 H1
185 	 *  (3) A2 B2 C2 D2 E2 F2 G2 H2
186 	 *  (4) A3 B3 C3 D3 E3 F3 G3 H3
187 	 *  (5) A4 B4 C4 D4 E4 F4 G4 H4
188 	 */
189 
190 	for (i = 0; i < (par->height / 8); i++) {
191 		for (j = 0; j < par->width; j++) {
192 			u32 array_idx = i * par->width + j;
193 			array->data[array_idx] = 0;
194 			for (k = 0; k < 8; k++) {
195 				u32 page_length = par->width * i;
196 				u32 index = page_length + (par->width * k + j) / 8;
197 				u8 byte = *(vmem + index);
198 				u8 bit = byte & (1 << (j % 8));
199 				bit = bit >> (j % 8);
200 				array->data[array_idx] |= bit << k;
201 			}
202 		}
203 	}
204 
205 	ssd1307fb_write_array(par->client, array, par->width * par->height / 8);
206 	kfree(array);
207 }
208 
209 
210 static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
211 		size_t count, loff_t *ppos)
212 {
213 	struct ssd1307fb_par *par = info->par;
214 	unsigned long total_size;
215 	unsigned long p = *ppos;
216 	u8 __iomem *dst;
217 
218 	total_size = info->fix.smem_len;
219 
220 	if (p > total_size)
221 		return -EINVAL;
222 
223 	if (count + p > total_size)
224 		count = total_size - p;
225 
226 	if (!count)
227 		return -EINVAL;
228 
229 	dst = (void __force *) (info->screen_base + p);
230 
231 	if (copy_from_user(dst, buf, count))
232 		return -EFAULT;
233 
234 	ssd1307fb_update_display(par);
235 
236 	*ppos += count;
237 
238 	return count;
239 }
240 
241 static int ssd1307fb_blank(int blank_mode, struct fb_info *info)
242 {
243 	struct ssd1307fb_par *par = info->par;
244 
245 	if (blank_mode != FB_BLANK_UNBLANK)
246 		return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
247 	else
248 		return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
249 }
250 
251 static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
252 {
253 	struct ssd1307fb_par *par = info->par;
254 	sys_fillrect(info, rect);
255 	ssd1307fb_update_display(par);
256 }
257 
258 static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
259 {
260 	struct ssd1307fb_par *par = info->par;
261 	sys_copyarea(info, area);
262 	ssd1307fb_update_display(par);
263 }
264 
265 static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image)
266 {
267 	struct ssd1307fb_par *par = info->par;
268 	sys_imageblit(info, image);
269 	ssd1307fb_update_display(par);
270 }
271 
272 static struct fb_ops ssd1307fb_ops = {
273 	.owner		= THIS_MODULE,
274 	.fb_read	= fb_sys_read,
275 	.fb_write	= ssd1307fb_write,
276 	.fb_blank	= ssd1307fb_blank,
277 	.fb_fillrect	= ssd1307fb_fillrect,
278 	.fb_copyarea	= ssd1307fb_copyarea,
279 	.fb_imageblit	= ssd1307fb_imageblit,
280 };
281 
282 static void ssd1307fb_deferred_io(struct fb_info *info,
283 				struct list_head *pagelist)
284 {
285 	ssd1307fb_update_display(info->par);
286 }
287 
288 static int ssd1307fb_init(struct ssd1307fb_par *par)
289 {
290 	int ret;
291 	u32 precharge, dclk, com_invdir, compins;
292 	struct pwm_args pargs;
293 
294 	if (par->device_info->need_pwm) {
295 		par->pwm = pwm_get(&par->client->dev, NULL);
296 		if (IS_ERR(par->pwm)) {
297 			dev_err(&par->client->dev, "Could not get PWM from device tree!\n");
298 			return PTR_ERR(par->pwm);
299 		}
300 
301 		/*
302 		 * FIXME: pwm_apply_args() should be removed when switching to
303 		 * the atomic PWM API.
304 		 */
305 		pwm_apply_args(par->pwm);
306 
307 		pwm_get_args(par->pwm, &pargs);
308 
309 		par->pwm_period = pargs.period;
310 		/* Enable the PWM */
311 		pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
312 		pwm_enable(par->pwm);
313 
314 		dev_dbg(&par->client->dev, "Using PWM%d with a %dns period.\n",
315 			par->pwm->pwm, par->pwm_period);
316 	};
317 
318 	/* Set initial contrast */
319 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
320 	if (ret < 0)
321 		return ret;
322 
323 	ret = ssd1307fb_write_cmd(par->client, par->contrast);
324 	if (ret < 0)
325 		return ret;
326 
327 	/* Set segment re-map */
328 	if (par->seg_remap) {
329 		ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
330 		if (ret < 0)
331 			return ret;
332 	};
333 
334 	/* Set COM direction */
335 	com_invdir = 0xc0 | (par->com_invdir & 0x1) << 3;
336 	ret = ssd1307fb_write_cmd(par->client,  com_invdir);
337 	if (ret < 0)
338 		return ret;
339 
340 	/* Set multiplex ratio value */
341 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO);
342 	if (ret < 0)
343 		return ret;
344 
345 	ret = ssd1307fb_write_cmd(par->client, par->height - 1);
346 	if (ret < 0)
347 		return ret;
348 
349 	/* set display offset value */
350 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET);
351 	if (ret < 0)
352 		return ret;
353 
354 	ret = ssd1307fb_write_cmd(par->client, par->com_offset);
355 	if (ret < 0)
356 		return ret;
357 
358 	/* Set clock frequency */
359 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ);
360 	if (ret < 0)
361 		return ret;
362 
363 	dclk = ((par->dclk_div - 1) & 0xf) | (par->dclk_frq & 0xf) << 4;
364 	ret = ssd1307fb_write_cmd(par->client, dclk);
365 	if (ret < 0)
366 		return ret;
367 
368 	/* Set precharge period in number of ticks from the internal clock */
369 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD);
370 	if (ret < 0)
371 		return ret;
372 
373 	precharge = (par->prechargep1 & 0xf) | (par->prechargep2 & 0xf) << 4;
374 	ret = ssd1307fb_write_cmd(par->client, precharge);
375 	if (ret < 0)
376 		return ret;
377 
378 	/* Set COM pins configuration */
379 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG);
380 	if (ret < 0)
381 		return ret;
382 
383 	compins = 0x02 | !(par->com_seq & 0x1) << 4
384 				   | (par->com_lrremap & 0x1) << 5;
385 	ret = ssd1307fb_write_cmd(par->client, compins);
386 	if (ret < 0)
387 		return ret;
388 
389 	/* Set VCOMH */
390 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH);
391 	if (ret < 0)
392 		return ret;
393 
394 	ret = ssd1307fb_write_cmd(par->client, par->vcomh);
395 	if (ret < 0)
396 		return ret;
397 
398 	/* Turn on the DC-DC Charge Pump */
399 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
400 	if (ret < 0)
401 		return ret;
402 
403 	ret = ssd1307fb_write_cmd(par->client,
404 		BIT(4) | (par->device_info->need_chargepump ? BIT(2) : 0));
405 	if (ret < 0)
406 		return ret;
407 
408 	/* Switch to horizontal addressing mode */
409 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_ADDRESS_MODE);
410 	if (ret < 0)
411 		return ret;
412 
413 	ret = ssd1307fb_write_cmd(par->client,
414 				  SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL);
415 	if (ret < 0)
416 		return ret;
417 
418 	/* Set column range */
419 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
420 	if (ret < 0)
421 		return ret;
422 
423 	ret = ssd1307fb_write_cmd(par->client, 0x0);
424 	if (ret < 0)
425 		return ret;
426 
427 	ret = ssd1307fb_write_cmd(par->client, par->width - 1);
428 	if (ret < 0)
429 		return ret;
430 
431 	/* Set page range */
432 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
433 	if (ret < 0)
434 		return ret;
435 
436 	ret = ssd1307fb_write_cmd(par->client, 0x0);
437 	if (ret < 0)
438 		return ret;
439 
440 	ret = ssd1307fb_write_cmd(par->client,
441 				  par->page_offset + (par->height / 8) - 1);
442 	if (ret < 0)
443 		return ret;
444 
445 	/* Clear the screen */
446 	ssd1307fb_update_display(par);
447 
448 	/* Turn on the display */
449 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
450 	if (ret < 0)
451 		return ret;
452 
453 	return 0;
454 }
455 
456 static int ssd1307fb_update_bl(struct backlight_device *bdev)
457 {
458 	struct ssd1307fb_par *par = bl_get_data(bdev);
459 	int ret;
460 	int brightness = bdev->props.brightness;
461 
462 	par->contrast = brightness;
463 
464 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
465 	if (ret < 0)
466 		return ret;
467 	ret = ssd1307fb_write_cmd(par->client, par->contrast);
468 	if (ret < 0)
469 		return ret;
470 	return 0;
471 }
472 
473 static int ssd1307fb_get_brightness(struct backlight_device *bdev)
474 {
475 	struct ssd1307fb_par *par = bl_get_data(bdev);
476 
477 	return par->contrast;
478 }
479 
480 static int ssd1307fb_check_fb(struct backlight_device *bdev,
481 				   struct fb_info *info)
482 {
483 	return (info->bl_dev == bdev);
484 }
485 
486 static const struct backlight_ops ssd1307fb_bl_ops = {
487 	.options	= BL_CORE_SUSPENDRESUME,
488 	.update_status	= ssd1307fb_update_bl,
489 	.get_brightness	= ssd1307fb_get_brightness,
490 	.check_fb	= ssd1307fb_check_fb,
491 };
492 
493 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1305_deviceinfo = {
494 	.default_vcomh = 0x34,
495 	.default_dclk_div = 1,
496 	.default_dclk_frq = 7,
497 };
498 
499 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1306_deviceinfo = {
500 	.default_vcomh = 0x20,
501 	.default_dclk_div = 1,
502 	.default_dclk_frq = 8,
503 	.need_chargepump = 1,
504 };
505 
506 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1307_deviceinfo = {
507 	.default_vcomh = 0x20,
508 	.default_dclk_div = 2,
509 	.default_dclk_frq = 12,
510 	.need_pwm = 1,
511 };
512 
513 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1309_deviceinfo = {
514 	.default_vcomh = 0x34,
515 	.default_dclk_div = 1,
516 	.default_dclk_frq = 10,
517 };
518 
519 static const struct of_device_id ssd1307fb_of_match[] = {
520 	{
521 		.compatible = "solomon,ssd1305fb-i2c",
522 		.data = (void *)&ssd1307fb_ssd1305_deviceinfo,
523 	},
524 	{
525 		.compatible = "solomon,ssd1306fb-i2c",
526 		.data = (void *)&ssd1307fb_ssd1306_deviceinfo,
527 	},
528 	{
529 		.compatible = "solomon,ssd1307fb-i2c",
530 		.data = (void *)&ssd1307fb_ssd1307_deviceinfo,
531 	},
532 	{
533 		.compatible = "solomon,ssd1309fb-i2c",
534 		.data = (void *)&ssd1307fb_ssd1309_deviceinfo,
535 	},
536 	{},
537 };
538 MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
539 
540 static int ssd1307fb_probe(struct i2c_client *client,
541 			   const struct i2c_device_id *id)
542 {
543 	struct backlight_device *bl;
544 	char bl_name[12];
545 	struct fb_info *info;
546 	struct device_node *node = client->dev.of_node;
547 	struct fb_deferred_io *ssd1307fb_defio;
548 	u32 vmem_size;
549 	struct ssd1307fb_par *par;
550 	u8 *vmem;
551 	int ret;
552 
553 	if (!node) {
554 		dev_err(&client->dev, "No device tree data found!\n");
555 		return -EINVAL;
556 	}
557 
558 	info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev);
559 	if (!info) {
560 		dev_err(&client->dev, "Couldn't allocate framebuffer.\n");
561 		return -ENOMEM;
562 	}
563 
564 	par = info->par;
565 	par->info = info;
566 	par->client = client;
567 
568 	par->device_info = of_device_get_match_data(&client->dev);
569 
570 	par->reset = devm_gpiod_get_optional(&client->dev, "reset",
571 					     GPIOD_OUT_LOW);
572 	if (IS_ERR(par->reset)) {
573 		dev_err(&client->dev, "failed to get reset gpio: %ld\n",
574 			PTR_ERR(par->reset));
575 		ret = PTR_ERR(par->reset);
576 		goto fb_alloc_error;
577 	}
578 
579 	par->vbat_reg = devm_regulator_get_optional(&client->dev, "vbat");
580 	if (IS_ERR(par->vbat_reg)) {
581 		ret = PTR_ERR(par->vbat_reg);
582 		if (ret == -ENODEV) {
583 			par->vbat_reg = NULL;
584 		} else {
585 			dev_err(&client->dev, "failed to get VBAT regulator: %d\n",
586 				ret);
587 			goto fb_alloc_error;
588 		}
589 	}
590 
591 	if (of_property_read_u32(node, "solomon,width", &par->width))
592 		par->width = 96;
593 
594 	if (of_property_read_u32(node, "solomon,height", &par->height))
595 		par->height = 16;
596 
597 	if (of_property_read_u32(node, "solomon,page-offset", &par->page_offset))
598 		par->page_offset = 1;
599 
600 	if (of_property_read_u32(node, "solomon,com-offset", &par->com_offset))
601 		par->com_offset = 0;
602 
603 	if (of_property_read_u32(node, "solomon,prechargep1", &par->prechargep1))
604 		par->prechargep1 = 2;
605 
606 	if (of_property_read_u32(node, "solomon,prechargep2", &par->prechargep2))
607 		par->prechargep2 = 2;
608 
609 	par->seg_remap = !of_property_read_bool(node, "solomon,segment-no-remap");
610 	par->com_seq = of_property_read_bool(node, "solomon,com-seq");
611 	par->com_lrremap = of_property_read_bool(node, "solomon,com-lrremap");
612 	par->com_invdir = of_property_read_bool(node, "solomon,com-invdir");
613 
614 	par->contrast = 127;
615 	par->vcomh = par->device_info->default_vcomh;
616 
617 	/* Setup display timing */
618 	par->dclk_div = par->device_info->default_dclk_div;
619 	par->dclk_frq = par->device_info->default_dclk_frq;
620 
621 	vmem_size = par->width * par->height / 8;
622 
623 	vmem = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
624 					get_order(vmem_size));
625 	if (!vmem) {
626 		dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
627 		ret = -ENOMEM;
628 		goto fb_alloc_error;
629 	}
630 
631 	ssd1307fb_defio = devm_kzalloc(&client->dev, sizeof(*ssd1307fb_defio),
632 				       GFP_KERNEL);
633 	if (!ssd1307fb_defio) {
634 		dev_err(&client->dev, "Couldn't allocate deferred io.\n");
635 		ret = -ENOMEM;
636 		goto fb_alloc_error;
637 	}
638 
639 	ssd1307fb_defio->delay = HZ / refreshrate;
640 	ssd1307fb_defio->deferred_io = ssd1307fb_deferred_io;
641 
642 	info->fbops = &ssd1307fb_ops;
643 	info->fix = ssd1307fb_fix;
644 	info->fix.line_length = par->width / 8;
645 	info->fbdefio = ssd1307fb_defio;
646 
647 	info->var = ssd1307fb_var;
648 	info->var.xres = par->width;
649 	info->var.xres_virtual = par->width;
650 	info->var.yres = par->height;
651 	info->var.yres_virtual = par->height;
652 
653 	info->var.red.length = 1;
654 	info->var.red.offset = 0;
655 	info->var.green.length = 1;
656 	info->var.green.offset = 0;
657 	info->var.blue.length = 1;
658 	info->var.blue.offset = 0;
659 
660 	info->screen_base = (u8 __force __iomem *)vmem;
661 	info->fix.smem_start = __pa(vmem);
662 	info->fix.smem_len = vmem_size;
663 
664 	fb_deferred_io_init(info);
665 
666 	i2c_set_clientdata(client, info);
667 
668 	if (par->reset) {
669 		/* Reset the screen */
670 		gpiod_set_value_cansleep(par->reset, 0);
671 		udelay(4);
672 		gpiod_set_value_cansleep(par->reset, 1);
673 		udelay(4);
674 	}
675 
676 	if (par->vbat_reg) {
677 		ret = regulator_enable(par->vbat_reg);
678 		if (ret) {
679 			dev_err(&client->dev, "failed to enable VBAT: %d\n",
680 				ret);
681 			goto reset_oled_error;
682 		}
683 	}
684 
685 	ret = ssd1307fb_init(par);
686 	if (ret)
687 		goto regulator_enable_error;
688 
689 	ret = register_framebuffer(info);
690 	if (ret) {
691 		dev_err(&client->dev, "Couldn't register the framebuffer\n");
692 		goto panel_init_error;
693 	}
694 
695 	snprintf(bl_name, sizeof(bl_name), "ssd1307fb%d", info->node);
696 	bl = backlight_device_register(bl_name, &client->dev, par,
697 				       &ssd1307fb_bl_ops, NULL);
698 	if (IS_ERR(bl)) {
699 		ret = PTR_ERR(bl);
700 		dev_err(&client->dev, "unable to register backlight device: %d\n",
701 			ret);
702 		goto bl_init_error;
703 	}
704 
705 	bl->props.brightness = par->contrast;
706 	bl->props.max_brightness = MAX_CONTRAST;
707 	info->bl_dev = bl;
708 
709 	dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
710 
711 	return 0;
712 
713 bl_init_error:
714 	unregister_framebuffer(info);
715 panel_init_error:
716 	if (par->device_info->need_pwm) {
717 		pwm_disable(par->pwm);
718 		pwm_put(par->pwm);
719 	};
720 regulator_enable_error:
721 	if (par->vbat_reg)
722 		regulator_disable(par->vbat_reg);
723 reset_oled_error:
724 	fb_deferred_io_cleanup(info);
725 fb_alloc_error:
726 	framebuffer_release(info);
727 	return ret;
728 }
729 
730 static int ssd1307fb_remove(struct i2c_client *client)
731 {
732 	struct fb_info *info = i2c_get_clientdata(client);
733 	struct ssd1307fb_par *par = info->par;
734 
735 	ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
736 
737 	backlight_device_unregister(info->bl_dev);
738 
739 	unregister_framebuffer(info);
740 	if (par->device_info->need_pwm) {
741 		pwm_disable(par->pwm);
742 		pwm_put(par->pwm);
743 	};
744 	fb_deferred_io_cleanup(info);
745 	__free_pages(__va(info->fix.smem_start), get_order(info->fix.smem_len));
746 	framebuffer_release(info);
747 
748 	return 0;
749 }
750 
751 static const struct i2c_device_id ssd1307fb_i2c_id[] = {
752 	{ "ssd1305fb", 0 },
753 	{ "ssd1306fb", 0 },
754 	{ "ssd1307fb", 0 },
755 	{ "ssd1309fb", 0 },
756 	{ }
757 };
758 MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id);
759 
760 static struct i2c_driver ssd1307fb_driver = {
761 	.probe = ssd1307fb_probe,
762 	.remove = ssd1307fb_remove,
763 	.id_table = ssd1307fb_i2c_id,
764 	.driver = {
765 		.name = "ssd1307fb",
766 		.of_match_table = ssd1307fb_of_match,
767 	},
768 };
769 
770 module_i2c_driver(ssd1307fb_driver);
771 
772 MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controller");
773 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
774 MODULE_LICENSE("GPL");
775