xref: /linux/drivers/hid/hid-picolcd_fb.c (revision 2fb7eb3d7e8c5c0375c726c7d5c443e6f7e53741)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /***************************************************************************
3  *   Copyright (C) 2010-2012 by Bruno Prémont <bonbons@linux-vserver.org>  *
4  *                                                                         *
5  *   Based on Logitech G13 driver (v0.4)                                   *
6  *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard@cs.nmsu.edu>   *
7  *                                                                         *
8  ***************************************************************************/
9 
10 #include <linux/hid.h>
11 #include <linux/vmalloc.h>
12 
13 #include <linux/fb.h>
14 #include <linux/module.h>
15 
16 #include "hid-picolcd.h"
17 
18 /* Framebuffer
19  *
20  * The PicoLCD use a Topway LCD module of 256x64 pixel
21  * This display area is tiled over 4 controllers with 8 tiles
22  * each. Each tile has 8x64 pixel, each data byte representing
23  * a 1-bit wide vertical line of the tile.
24  *
25  * The display can be updated at a tile granularity.
26  *
27  *       Chip 1           Chip 2           Chip 3           Chip 4
28  * +----------------+----------------+----------------+----------------+
29  * |     Tile 1     |     Tile 1     |     Tile 1     |     Tile 1     |
30  * +----------------+----------------+----------------+----------------+
31  * |     Tile 2     |     Tile 2     |     Tile 2     |     Tile 2     |
32  * +----------------+----------------+----------------+----------------+
33  *                                  ...
34  * +----------------+----------------+----------------+----------------+
35  * |     Tile 8     |     Tile 8     |     Tile 8     |     Tile 8     |
36  * +----------------+----------------+----------------+----------------+
37  */
38 #define PICOLCDFB_NAME "picolcdfb"
39 #define PICOLCDFB_WIDTH (256)
40 #define PICOLCDFB_HEIGHT (64)
41 #define PICOLCDFB_SIZE (PICOLCDFB_WIDTH * PICOLCDFB_HEIGHT / 8)
42 
43 #define PICOLCDFB_UPDATE_RATE_LIMIT   10
44 #define PICOLCDFB_UPDATE_RATE_DEFAULT  2
45 
46 /* Framebuffer visual structures */
47 static const struct fb_fix_screeninfo picolcdfb_fix = {
48 	.id          = PICOLCDFB_NAME,
49 	.type        = FB_TYPE_PACKED_PIXELS,
50 	.visual      = FB_VISUAL_MONO01,
51 	.xpanstep    = 0,
52 	.ypanstep    = 0,
53 	.ywrapstep   = 0,
54 	.line_length = PICOLCDFB_WIDTH / 8,
55 	.accel       = FB_ACCEL_NONE,
56 };
57 
58 static const struct fb_var_screeninfo picolcdfb_var = {
59 	.xres           = PICOLCDFB_WIDTH,
60 	.yres           = PICOLCDFB_HEIGHT,
61 	.xres_virtual   = PICOLCDFB_WIDTH,
62 	.yres_virtual   = PICOLCDFB_HEIGHT,
63 	.width          = 103,
64 	.height         = 26,
65 	.bits_per_pixel = 1,
66 	.grayscale      = 1,
67 	.red            = {
68 		.offset = 0,
69 		.length = 1,
70 		.msb_right = 0,
71 	},
72 	.green          = {
73 		.offset = 0,
74 		.length = 1,
75 		.msb_right = 0,
76 	},
77 	.blue           = {
78 		.offset = 0,
79 		.length = 1,
80 		.msb_right = 0,
81 	},
82 	.transp         = {
83 		.offset = 0,
84 		.length = 0,
85 		.msb_right = 0,
86 	},
87 };
88 
89 /* Send a given tile to PicoLCD */
picolcd_fb_send_tile(struct picolcd_data * data,u8 * vbitmap,int chip,int tile)90 static int picolcd_fb_send_tile(struct picolcd_data *data, u8 *vbitmap,
91 		int chip, int tile)
92 {
93 	struct hid_report *report1, *report2;
94 	unsigned long flags;
95 	u8 *tdata;
96 	int i;
97 
98 	report1 = picolcd_out_report(REPORT_LCD_CMD_DATA, data->hdev);
99 	if (!report1 || report1->maxfield != 1)
100 		return -ENODEV;
101 	report2 = picolcd_out_report(REPORT_LCD_DATA, data->hdev);
102 	if (!report2 || report2->maxfield != 1)
103 		return -ENODEV;
104 
105 	spin_lock_irqsave(&data->lock, flags);
106 	if ((data->status & PICOLCD_FAILED)) {
107 		spin_unlock_irqrestore(&data->lock, flags);
108 		return -ENODEV;
109 	}
110 	hid_set_field(report1->field[0],  0, chip << 2);
111 	hid_set_field(report1->field[0],  1, 0x02);
112 	hid_set_field(report1->field[0],  2, 0x00);
113 	hid_set_field(report1->field[0],  3, 0x00);
114 	hid_set_field(report1->field[0],  4, 0xb8 | tile);
115 	hid_set_field(report1->field[0],  5, 0x00);
116 	hid_set_field(report1->field[0],  6, 0x00);
117 	hid_set_field(report1->field[0],  7, 0x40);
118 	hid_set_field(report1->field[0],  8, 0x00);
119 	hid_set_field(report1->field[0],  9, 0x00);
120 	hid_set_field(report1->field[0], 10,   32);
121 
122 	hid_set_field(report2->field[0],  0, (chip << 2) | 0x01);
123 	hid_set_field(report2->field[0],  1, 0x00);
124 	hid_set_field(report2->field[0],  2, 0x00);
125 	hid_set_field(report2->field[0],  3,   32);
126 
127 	tdata = vbitmap + (tile * 4 + chip) * 64;
128 	for (i = 0; i < 64; i++)
129 		if (i < 32)
130 			hid_set_field(report1->field[0], 11 + i, tdata[i]);
131 		else
132 			hid_set_field(report2->field[0], 4 + i - 32, tdata[i]);
133 
134 	hid_hw_request(data->hdev, report1, HID_REQ_SET_REPORT);
135 	hid_hw_request(data->hdev, report2, HID_REQ_SET_REPORT);
136 	spin_unlock_irqrestore(&data->lock, flags);
137 	return 0;
138 }
139 
140 /* Translate a single tile*/
picolcd_fb_update_tile(u8 * vbitmap,const u8 * bitmap,int bpp,int chip,int tile)141 static int picolcd_fb_update_tile(u8 *vbitmap, const u8 *bitmap, int bpp,
142 		int chip, int tile)
143 {
144 	int i, b, changed = 0;
145 	u8 tdata[64];
146 	u8 *vdata = vbitmap + (tile * 4 + chip) * 64;
147 
148 	if (bpp == 1) {
149 		for (b = 7; b >= 0; b--) {
150 			const u8 *bdata = bitmap + tile * 256 + chip * 8 + b * 32;
151 			for (i = 0; i < 64; i++) {
152 				tdata[i] <<= 1;
153 				tdata[i] |= (bdata[i/8] >> (i % 8)) & 0x01;
154 			}
155 		}
156 	} else if (bpp == 8) {
157 		for (b = 7; b >= 0; b--) {
158 			const u8 *bdata = bitmap + (tile * 256 + chip * 8 + b * 32) * 8;
159 			for (i = 0; i < 64; i++) {
160 				tdata[i] <<= 1;
161 				tdata[i] |= (bdata[i] & 0x80) ? 0x01 : 0x00;
162 			}
163 		}
164 	} else {
165 		/* Oops, we should never get here! */
166 		WARN_ON(1);
167 		return 0;
168 	}
169 
170 	for (i = 0; i < 64; i++)
171 		if (tdata[i] != vdata[i]) {
172 			changed = 1;
173 			vdata[i] = tdata[i];
174 		}
175 	return changed;
176 }
177 
picolcd_fb_refresh(struct picolcd_data * data)178 void picolcd_fb_refresh(struct picolcd_data *data)
179 {
180 	if (data->fb_info)
181 		schedule_delayed_work(&data->fb_info->deferred_work, 0);
182 }
183 
184 /* Reconfigure LCD display */
picolcd_fb_reset(struct picolcd_data * data,int clear)185 int picolcd_fb_reset(struct picolcd_data *data, int clear)
186 {
187 	struct hid_report *report = picolcd_out_report(REPORT_LCD_CMD, data->hdev);
188 	struct picolcd_fb_data *fbdata = data->fb_info->par;
189 	int i, j;
190 	unsigned long flags;
191 	static const u8 mapcmd[8] = { 0x00, 0x02, 0x00, 0x64, 0x3f, 0x00, 0x64, 0xc0 };
192 
193 	if (!report || report->maxfield != 1)
194 		return -ENODEV;
195 
196 	spin_lock_irqsave(&data->lock, flags);
197 	for (i = 0; i < 4; i++) {
198 		for (j = 0; j < report->field[0]->maxusage; j++)
199 			if (j == 0)
200 				hid_set_field(report->field[0], j, i << 2);
201 			else if (j < sizeof(mapcmd))
202 				hid_set_field(report->field[0], j, mapcmd[j]);
203 			else
204 				hid_set_field(report->field[0], j, 0);
205 		hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
206 	}
207 	spin_unlock_irqrestore(&data->lock, flags);
208 
209 	if (clear) {
210 		memset(fbdata->vbitmap, 0, PICOLCDFB_SIZE);
211 		memset(fbdata->bitmap, 0, PICOLCDFB_SIZE*fbdata->bpp);
212 	}
213 	fbdata->force = 1;
214 
215 	/* schedule first output of framebuffer */
216 	if (fbdata->ready)
217 		schedule_delayed_work(&data->fb_info->deferred_work, 0);
218 	else
219 		fbdata->ready = 1;
220 
221 	return 0;
222 }
223 
224 /* Update fb_vbitmap from the screen_buffer and send changed tiles to device */
picolcd_fb_update(struct fb_info * info)225 static void picolcd_fb_update(struct fb_info *info)
226 {
227 	int chip, tile, n;
228 	unsigned long flags;
229 	struct picolcd_fb_data *fbdata = info->par;
230 	struct picolcd_data *data;
231 
232 	mutex_lock(&info->lock);
233 
234 	spin_lock_irqsave(&fbdata->lock, flags);
235 	if (!fbdata->ready && fbdata->picolcd)
236 		picolcd_fb_reset(fbdata->picolcd, 0);
237 	spin_unlock_irqrestore(&fbdata->lock, flags);
238 
239 	/*
240 	 * Translate the framebuffer into the format needed by the PicoLCD.
241 	 * See display layout above.
242 	 * Do this one tile after the other and push those tiles that changed.
243 	 *
244 	 * Wait for our IO to complete as otherwise we might flood the queue!
245 	 */
246 	n = 0;
247 	for (chip = 0; chip < 4; chip++)
248 		for (tile = 0; tile < 8; tile++) {
249 			if (!fbdata->force && !picolcd_fb_update_tile(
250 					fbdata->vbitmap, fbdata->bitmap,
251 					fbdata->bpp, chip, tile))
252 				continue;
253 			n += 2;
254 			if (n >= HID_OUTPUT_FIFO_SIZE / 2) {
255 				spin_lock_irqsave(&fbdata->lock, flags);
256 				data = fbdata->picolcd;
257 				spin_unlock_irqrestore(&fbdata->lock, flags);
258 				mutex_unlock(&info->lock);
259 				if (!data)
260 					return;
261 				hid_hw_wait(data->hdev);
262 				mutex_lock(&info->lock);
263 				n = 0;
264 			}
265 			spin_lock_irqsave(&fbdata->lock, flags);
266 			data = fbdata->picolcd;
267 			spin_unlock_irqrestore(&fbdata->lock, flags);
268 			if (!data || picolcd_fb_send_tile(data,
269 					fbdata->vbitmap, chip, tile))
270 				goto out;
271 		}
272 	fbdata->force = false;
273 	if (n) {
274 		spin_lock_irqsave(&fbdata->lock, flags);
275 		data = fbdata->picolcd;
276 		spin_unlock_irqrestore(&fbdata->lock, flags);
277 		mutex_unlock(&info->lock);
278 		if (data)
279 			hid_hw_wait(data->hdev);
280 		return;
281 	}
282 out:
283 	mutex_unlock(&info->lock);
284 }
285 
picolcd_fb_blank(int blank,struct fb_info * info)286 static int picolcd_fb_blank(int blank, struct fb_info *info)
287 {
288 	/* We let fb notification do this for us via lcd/backlight device */
289 	return 0;
290 }
291 
picolcd_fb_destroy(struct fb_info * info)292 static void picolcd_fb_destroy(struct fb_info *info)
293 {
294 	struct picolcd_fb_data *fbdata = info->par;
295 
296 	/* make sure no work is deferred */
297 	fb_deferred_io_cleanup(info);
298 
299 	/* No thirdparty should ever unregister our framebuffer! */
300 	WARN_ON(fbdata->picolcd != NULL);
301 
302 	vfree((u8 *)info->fix.smem_start);
303 	framebuffer_release(info);
304 }
305 
picolcd_fb_check_var(struct fb_var_screeninfo * var,struct fb_info * info)306 static int picolcd_fb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
307 {
308 	__u32 bpp      = var->bits_per_pixel;
309 	__u32 activate = var->activate;
310 
311 	/* only allow 1/8 bit depth (8-bit is grayscale) */
312 	*var = picolcdfb_var;
313 	var->activate = activate;
314 	if (bpp >= 8) {
315 		var->bits_per_pixel = 8;
316 		var->red.length     = 8;
317 		var->green.length   = 8;
318 		var->blue.length    = 8;
319 	} else {
320 		var->bits_per_pixel = 1;
321 		var->red.length     = 1;
322 		var->green.length   = 1;
323 		var->blue.length    = 1;
324 	}
325 	return 0;
326 }
327 
picolcd_set_par(struct fb_info * info)328 static int picolcd_set_par(struct fb_info *info)
329 {
330 	struct picolcd_fb_data *fbdata = info->par;
331 	u8 *tmp_fb, *o_fb;
332 	if (info->var.bits_per_pixel == fbdata->bpp)
333 		return 0;
334 	/* switch between 1/8 bit depths */
335 	if (info->var.bits_per_pixel != 1 && info->var.bits_per_pixel != 8)
336 		return -EINVAL;
337 
338 	o_fb   = fbdata->bitmap;
339 	tmp_fb = kmalloc_array(PICOLCDFB_SIZE, info->var.bits_per_pixel,
340 			       GFP_KERNEL);
341 	if (!tmp_fb)
342 		return -ENOMEM;
343 
344 	/* translate FB content to new bits-per-pixel */
345 	if (info->var.bits_per_pixel == 1) {
346 		int i, b;
347 		for (i = 0; i < PICOLCDFB_SIZE; i++) {
348 			u8 p = 0;
349 			for (b = 0; b < 8; b++) {
350 				p <<= 1;
351 				p |= o_fb[i*8+b] ? 0x01 : 0x00;
352 			}
353 			tmp_fb[i] = p;
354 		}
355 		memcpy(o_fb, tmp_fb, PICOLCDFB_SIZE);
356 		info->fix.visual = FB_VISUAL_MONO01;
357 		info->fix.line_length = PICOLCDFB_WIDTH / 8;
358 	} else {
359 		int i;
360 		memcpy(tmp_fb, o_fb, PICOLCDFB_SIZE);
361 		for (i = 0; i < PICOLCDFB_SIZE * 8; i++)
362 			o_fb[i] = tmp_fb[i/8] & (0x01 << (7 - i % 8)) ? 0xff : 0x00;
363 		info->fix.visual = FB_VISUAL_DIRECTCOLOR;
364 		info->fix.line_length = PICOLCDFB_WIDTH;
365 	}
366 
367 	kfree(tmp_fb);
368 	fbdata->bpp = info->var.bits_per_pixel;
369 	return 0;
370 }
371 
picolcdfb_ops_damage_range(struct fb_info * info,off_t off,size_t len)372 static void picolcdfb_ops_damage_range(struct fb_info *info, off_t off, size_t len)
373 {
374 	if (!info->par)
375 		return;
376 	schedule_delayed_work(&info->deferred_work, 0);
377 }
378 
picolcdfb_ops_damage_area(struct fb_info * info,u32 x,u32 y,u32 width,u32 height)379 static void picolcdfb_ops_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height)
380 {
381 	if (!info->par)
382 		return;
383 	schedule_delayed_work(&info->deferred_work, 0);
384 }
385 
386 FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(picolcdfb_ops,
387 				   picolcdfb_ops_damage_range,
388 				   picolcdfb_ops_damage_area)
389 
390 static const struct fb_ops picolcdfb_ops = {
391 	.owner        = THIS_MODULE,
392 	FB_DEFAULT_DEFERRED_OPS(picolcdfb_ops),
393 	.fb_destroy   = picolcd_fb_destroy,
394 	.fb_blank     = picolcd_fb_blank,
395 	.fb_check_var = picolcd_fb_check_var,
396 	.fb_set_par   = picolcd_set_par,
397 };
398 
399 
400 /* Callback from deferred IO workqueue */
picolcd_fb_deferred_io(struct fb_info * info,struct list_head * pagereflist)401 static void picolcd_fb_deferred_io(struct fb_info *info, struct list_head *pagereflist)
402 {
403 	picolcd_fb_update(info);
404 }
405 
406 static const struct fb_deferred_io picolcd_fb_defio = {
407 	.delay = HZ / PICOLCDFB_UPDATE_RATE_DEFAULT,
408 	.deferred_io = picolcd_fb_deferred_io,
409 };
410 
411 
412 /*
413  * The "fb_update_rate" sysfs attribute
414  */
picolcd_fb_update_rate_show(struct device * dev,struct device_attribute * attr,char * buf)415 static ssize_t picolcd_fb_update_rate_show(struct device *dev,
416 		struct device_attribute *attr, char *buf)
417 {
418 	struct picolcd_data *data = dev_get_drvdata(dev);
419 	struct picolcd_fb_data *fbdata = data->fb_info->par;
420 	unsigned i, fb_update_rate = fbdata->update_rate;
421 	size_t ret = 0;
422 
423 	for (i = 1; i <= PICOLCDFB_UPDATE_RATE_LIMIT; i++)
424 		if (i == fb_update_rate)
425 			ret += sysfs_emit_at(buf, ret, "[%u] ", i);
426 		else
427 			ret += sysfs_emit_at(buf, ret, "%u ", i);
428 	if (ret > 0)
429 		buf[min(ret, (size_t)PAGE_SIZE)-1] = '\n';
430 	return ret;
431 }
432 
picolcd_fb_update_rate_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)433 static ssize_t picolcd_fb_update_rate_store(struct device *dev,
434 		struct device_attribute *attr, const char *buf, size_t count)
435 {
436 	struct picolcd_data *data = dev_get_drvdata(dev);
437 	struct picolcd_fb_data *fbdata = data->fb_info->par;
438 	int i;
439 	unsigned u;
440 
441 	if (count < 1 || count > 10)
442 		return -EINVAL;
443 
444 	i = sscanf(buf, "%u", &u);
445 	if (i != 1)
446 		return -EINVAL;
447 
448 	if (u > PICOLCDFB_UPDATE_RATE_LIMIT)
449 		return -ERANGE;
450 	else if (u == 0)
451 		u = PICOLCDFB_UPDATE_RATE_DEFAULT;
452 
453 	fbdata->update_rate = u;
454 	data->fb_info->fbdefio->delay = HZ / fbdata->update_rate;
455 	return count;
456 }
457 
458 static DEVICE_ATTR(fb_update_rate, 0664, picolcd_fb_update_rate_show,
459 		picolcd_fb_update_rate_store);
460 
461 /* initialize Framebuffer device */
picolcd_init_framebuffer(struct picolcd_data * data)462 int picolcd_init_framebuffer(struct picolcd_data *data)
463 {
464 	struct device *dev = &data->hdev->dev;
465 	struct fb_info *info = NULL;
466 	struct picolcd_fb_data *fbdata = NULL;
467 	int i, error = -ENOMEM;
468 	u32 *palette;
469 
470 	/* The extra memory is:
471 	 * - 256*u32 for pseudo_palette
472 	 * - struct fb_deferred_io
473 	 */
474 	info = framebuffer_alloc(256 * sizeof(u32) +
475 			sizeof(struct fb_deferred_io) +
476 			sizeof(struct picolcd_fb_data) +
477 			PICOLCDFB_SIZE, dev);
478 	if (!info)
479 		goto err_nomem;
480 
481 	info->fbdefio = info->par;
482 	*info->fbdefio = picolcd_fb_defio;
483 	info->par += sizeof(struct fb_deferred_io);
484 	palette = info->par;
485 	info->par += 256 * sizeof(u32);
486 	for (i = 0; i < 256; i++)
487 		palette[i] = i > 0 && i < 16 ? 0xff : 0;
488 	info->pseudo_palette = palette;
489 	info->fbops = &picolcdfb_ops;
490 	info->var = picolcdfb_var;
491 	info->fix = picolcdfb_fix;
492 	info->fix.smem_len   = PICOLCDFB_SIZE*8;
493 
494 #ifdef CONFIG_FB_BACKLIGHT
495 #ifdef CONFIG_HID_PICOLCD_BACKLIGHT
496 	info->bl_dev = data->backlight;
497 #endif
498 #endif
499 
500 #ifdef CONFIG_HID_PICOLCD_LCD
501 	info->lcd_dev = data->lcd;
502 #endif
503 
504 	fbdata = info->par;
505 	spin_lock_init(&fbdata->lock);
506 	fbdata->picolcd = data;
507 	fbdata->update_rate = PICOLCDFB_UPDATE_RATE_DEFAULT;
508 	fbdata->bpp     = picolcdfb_var.bits_per_pixel;
509 	fbdata->force   = 1;
510 	fbdata->vbitmap = info->par + sizeof(struct picolcd_fb_data);
511 	fbdata->bitmap  = vmalloc(PICOLCDFB_SIZE*8);
512 	if (fbdata->bitmap == NULL) {
513 		dev_err(dev, "can't get a free page for framebuffer\n");
514 		goto err_nomem;
515 	}
516 	info->flags |= FBINFO_VIRTFB;
517 	info->screen_buffer = fbdata->bitmap;
518 	info->fix.smem_start = (unsigned long)fbdata->bitmap;
519 	memset(fbdata->vbitmap, 0xff, PICOLCDFB_SIZE);
520 	data->fb_info = info;
521 
522 	error = picolcd_fb_reset(data, 1);
523 	if (error) {
524 		dev_err(dev, "failed to configure display\n");
525 		goto err_cleanup;
526 	}
527 
528 	error = device_create_file(dev, &dev_attr_fb_update_rate);
529 	if (error) {
530 		dev_err(dev, "failed to create sysfs attributes\n");
531 		goto err_cleanup;
532 	}
533 
534 	fb_deferred_io_init(info);
535 	error = register_framebuffer(info);
536 	if (error) {
537 		dev_err(dev, "failed to register framebuffer\n");
538 		goto err_sysfs;
539 	}
540 	return 0;
541 
542 err_sysfs:
543 	device_remove_file(dev, &dev_attr_fb_update_rate);
544 	fb_deferred_io_cleanup(info);
545 err_cleanup:
546 	data->fb_info    = NULL;
547 
548 err_nomem:
549 	if (fbdata)
550 		vfree(fbdata->bitmap);
551 	framebuffer_release(info);
552 	return error;
553 }
554 
picolcd_exit_framebuffer(struct picolcd_data * data)555 void picolcd_exit_framebuffer(struct picolcd_data *data)
556 {
557 	struct fb_info *info = data->fb_info;
558 	struct picolcd_fb_data *fbdata;
559 	unsigned long flags;
560 
561 	if (!info)
562 		return;
563 
564 	device_remove_file(&data->hdev->dev, &dev_attr_fb_update_rate);
565 	fbdata = info->par;
566 
567 	/* disconnect framebuffer from HID dev */
568 	spin_lock_irqsave(&fbdata->lock, flags);
569 	fbdata->picolcd = NULL;
570 	spin_unlock_irqrestore(&fbdata->lock, flags);
571 
572 	/* make sure there is no running update - thus that fbdata->picolcd
573 	 * once obtained under lock is guaranteed not to get free() under
574 	 * the feet of the deferred work */
575 	flush_delayed_work(&info->deferred_work);
576 
577 	data->fb_info = NULL;
578 	unregister_framebuffer(info);
579 }
580