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 */
47static 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
58static 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 */
90static 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(lock: &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(lock: &data->lock, flags);
137 return 0;
138}
139
140/* Translate a single tile*/
141static 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
178void picolcd_fb_refresh(struct picolcd_data *data)
179{
180 if (data->fb_info)
181 schedule_delayed_work(dwork: &data->fb_info->deferred_work, delay: 0);
182}
183
184/* Reconfigure LCD display */
185int 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(lock: &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(dwork: &data->fb_info->deferred_work, delay: 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 */
225static 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(data: fbdata->picolcd, clear: 0);
237 spin_unlock_irqrestore(lock: &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 vbitmap: fbdata->vbitmap, bitmap: fbdata->bitmap,
251 bpp: 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(lock: &fbdata->lock, flags);
258 mutex_unlock(lock: &info->lock);
259 if (!data)
260 return;
261 hid_hw_wait(hdev: 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(lock: &fbdata->lock, flags);
268 if (!data || picolcd_fb_send_tile(data,
269 vbitmap: 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(lock: &fbdata->lock, flags);
277 mutex_unlock(lock: &info->lock);
278 if (data)
279 hid_hw_wait(hdev: data->hdev);
280 return;
281 }
282out:
283 mutex_unlock(lock: &info->lock);
284}
285
286static 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
292static 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 thridparty should ever unregister our framebuffer! */
300 WARN_ON(fbdata->picolcd != NULL);
301
302 vfree(addr: (u8 *)info->fix.smem_start);
303 framebuffer_release(info);
304}
305
306static 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
328static 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, 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(objp: tmp_fb);
368 fbdata->bpp = info->var.bits_per_pixel;
369 return 0;
370}
371
372static 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(dwork: &info->deferred_work, delay: 0);
377}
378
379static 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(dwork: &info->deferred_work, delay: 0);
384}
385
386FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(picolcdfb_ops,
387 picolcdfb_ops_damage_range,
388 picolcdfb_ops_damage_area)
389
390static 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 */
401static void picolcd_fb_deferred_io(struct fb_info *info, struct list_head *pagereflist)
402{
403 picolcd_fb_update(info);
404}
405
406static 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 */
415static 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 (ret >= PAGE_SIZE)
425 break;
426 else if (i == fb_update_rate)
427 ret += scnprintf(buf: buf+ret, PAGE_SIZE-ret, fmt: "[%u] ", i);
428 else
429 ret += scnprintf(buf: buf+ret, PAGE_SIZE-ret, fmt: "%u ", i);
430 if (ret > 0)
431 buf[min(ret, (size_t)PAGE_SIZE)-1] = '\n';
432 return ret;
433}
434
435static ssize_t picolcd_fb_update_rate_store(struct device *dev,
436 struct device_attribute *attr, const char *buf, size_t count)
437{
438 struct picolcd_data *data = dev_get_drvdata(dev);
439 struct picolcd_fb_data *fbdata = data->fb_info->par;
440 int i;
441 unsigned u;
442
443 if (count < 1 || count > 10)
444 return -EINVAL;
445
446 i = sscanf(buf, "%u", &u);
447 if (i != 1)
448 return -EINVAL;
449
450 if (u > PICOLCDFB_UPDATE_RATE_LIMIT)
451 return -ERANGE;
452 else if (u == 0)
453 u = PICOLCDFB_UPDATE_RATE_DEFAULT;
454
455 fbdata->update_rate = u;
456 data->fb_info->fbdefio->delay = HZ / fbdata->update_rate;
457 return count;
458}
459
460static DEVICE_ATTR(fb_update_rate, 0664, picolcd_fb_update_rate_show,
461 picolcd_fb_update_rate_store);
462
463/* initialize Framebuffer device */
464int picolcd_init_framebuffer(struct picolcd_data *data)
465{
466 struct device *dev = &data->hdev->dev;
467 struct fb_info *info = NULL;
468 struct picolcd_fb_data *fbdata = NULL;
469 int i, error = -ENOMEM;
470 u32 *palette;
471
472 /* The extra memory is:
473 * - 256*u32 for pseudo_palette
474 * - struct fb_deferred_io
475 */
476 info = framebuffer_alloc(size: 256 * sizeof(u32) +
477 sizeof(struct fb_deferred_io) +
478 sizeof(struct picolcd_fb_data) +
479 PICOLCDFB_SIZE, dev);
480 if (!info)
481 goto err_nomem;
482
483 info->fbdefio = info->par;
484 *info->fbdefio = picolcd_fb_defio;
485 info->par += sizeof(struct fb_deferred_io);
486 palette = info->par;
487 info->par += 256 * sizeof(u32);
488 for (i = 0; i < 256; i++)
489 palette[i] = i > 0 && i < 16 ? 0xff : 0;
490 info->pseudo_palette = palette;
491 info->fbops = &picolcdfb_ops;
492 info->var = picolcdfb_var;
493 info->fix = picolcdfb_fix;
494 info->fix.smem_len = PICOLCDFB_SIZE*8;
495
496 fbdata = info->par;
497 spin_lock_init(&fbdata->lock);
498 fbdata->picolcd = data;
499 fbdata->update_rate = PICOLCDFB_UPDATE_RATE_DEFAULT;
500 fbdata->bpp = picolcdfb_var.bits_per_pixel;
501 fbdata->force = 1;
502 fbdata->vbitmap = info->par + sizeof(struct picolcd_fb_data);
503 fbdata->bitmap = vmalloc(PICOLCDFB_SIZE*8);
504 if (fbdata->bitmap == NULL) {
505 dev_err(dev, "can't get a free page for framebuffer\n");
506 goto err_nomem;
507 }
508 info->screen_buffer = fbdata->bitmap;
509 info->fix.smem_start = (unsigned long)fbdata->bitmap;
510 memset(fbdata->vbitmap, 0xff, PICOLCDFB_SIZE);
511 data->fb_info = info;
512
513 error = picolcd_fb_reset(data, clear: 1);
514 if (error) {
515 dev_err(dev, "failed to configure display\n");
516 goto err_cleanup;
517 }
518
519 error = device_create_file(device: dev, entry: &dev_attr_fb_update_rate);
520 if (error) {
521 dev_err(dev, "failed to create sysfs attributes\n");
522 goto err_cleanup;
523 }
524
525 fb_deferred_io_init(info);
526 error = register_framebuffer(fb_info: info);
527 if (error) {
528 dev_err(dev, "failed to register framebuffer\n");
529 goto err_sysfs;
530 }
531 return 0;
532
533err_sysfs:
534 device_remove_file(dev, attr: &dev_attr_fb_update_rate);
535 fb_deferred_io_cleanup(info);
536err_cleanup:
537 data->fb_info = NULL;
538
539err_nomem:
540 if (fbdata)
541 vfree(addr: fbdata->bitmap);
542 framebuffer_release(info);
543 return error;
544}
545
546void picolcd_exit_framebuffer(struct picolcd_data *data)
547{
548 struct fb_info *info = data->fb_info;
549 struct picolcd_fb_data *fbdata;
550 unsigned long flags;
551
552 if (!info)
553 return;
554
555 device_remove_file(dev: &data->hdev->dev, attr: &dev_attr_fb_update_rate);
556 fbdata = info->par;
557
558 /* disconnect framebuffer from HID dev */
559 spin_lock_irqsave(&fbdata->lock, flags);
560 fbdata->picolcd = NULL;
561 spin_unlock_irqrestore(lock: &fbdata->lock, flags);
562
563 /* make sure there is no running update - thus that fbdata->picolcd
564 * once obtained under lock is guaranteed not to get free() under
565 * the feet of the deferred work */
566 flush_delayed_work(dwork: &info->deferred_work);
567
568 data->fb_info = NULL;
569 unregister_framebuffer(fb_info: info);
570}
571

source code of linux/drivers/hid/hid-picolcd_fb.c