1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * DRM driver for Pervasive Displays RePaper branded e-ink panels
4 *
5 * Copyright 2013-2017 Pervasive Displays, Inc.
6 * Copyright 2017 Noralf Trønnes
7 *
8 * The driver supports:
9 * Material Film: Aurora Mb (V231)
10 * Driver IC: G2 (eTC)
11 *
12 * The controller code was taken from the userspace driver:
13 * https://github.com/repaper/gratis
14 */
15
16 #include <linux/delay.h>
17 #include <linux/gpio/consumer.h>
18 #include <linux/module.h>
19 #include <linux/property.h>
20 #include <linux/sched/clock.h>
21 #include <linux/spi/spi.h>
22 #include <linux/thermal.h>
23
24 #include <drm/drm_atomic_helper.h>
25 #include <drm/drm_connector.h>
26 #include <drm/drm_damage_helper.h>
27 #include <drm/drm_drv.h>
28 #include <drm/drm_fb_cma_helper.h>
29 #include <drm/drm_fb_helper.h>
30 #include <drm/drm_format_helper.h>
31 #include <drm/drm_gem_atomic_helper.h>
32 #include <drm/drm_gem_cma_helper.h>
33 #include <drm/drm_gem_framebuffer_helper.h>
34 #include <drm/drm_managed.h>
35 #include <drm/drm_modes.h>
36 #include <drm/drm_rect.h>
37 #include <drm/drm_probe_helper.h>
38 #include <drm/drm_simple_kms_helper.h>
39
40 #define REPAPER_RID_G2_COG_ID 0x12
41
42 enum repaper_model {
43 /* 0 is reserved to avoid clashing with NULL */
44 E1144CS021 = 1,
45 E1190CS021,
46 E2200CS021,
47 E2271CS021,
48 };
49
50 enum repaper_stage { /* Image pixel -> Display pixel */
51 REPAPER_COMPENSATE, /* B -> W, W -> B (Current Image) */
52 REPAPER_WHITE, /* B -> N, W -> W (Current Image) */
53 REPAPER_INVERSE, /* B -> N, W -> B (New Image) */
54 REPAPER_NORMAL /* B -> B, W -> W (New Image) */
55 };
56
57 enum repaper_epd_border_byte {
58 REPAPER_BORDER_BYTE_NONE,
59 REPAPER_BORDER_BYTE_ZERO,
60 REPAPER_BORDER_BYTE_SET,
61 };
62
63 struct repaper_epd {
64 struct drm_device drm;
65 struct drm_simple_display_pipe pipe;
66 const struct drm_display_mode *mode;
67 struct drm_connector connector;
68 struct spi_device *spi;
69
70 struct gpio_desc *panel_on;
71 struct gpio_desc *border;
72 struct gpio_desc *discharge;
73 struct gpio_desc *reset;
74 struct gpio_desc *busy;
75
76 struct thermal_zone_device *thermal;
77
78 unsigned int height;
79 unsigned int width;
80 unsigned int bytes_per_scan;
81 const u8 *channel_select;
82 unsigned int stage_time;
83 unsigned int factored_stage_time;
84 bool middle_scan;
85 bool pre_border_byte;
86 enum repaper_epd_border_byte border_byte;
87
88 u8 *line_buffer;
89 void *current_frame;
90
91 bool cleared;
92 bool partial;
93 };
94
drm_to_epd(struct drm_device * drm)95 static inline struct repaper_epd *drm_to_epd(struct drm_device *drm)
96 {
97 return container_of(drm, struct repaper_epd, drm);
98 }
99
repaper_spi_transfer(struct spi_device * spi,u8 header,const void * tx,void * rx,size_t len)100 static int repaper_spi_transfer(struct spi_device *spi, u8 header,
101 const void *tx, void *rx, size_t len)
102 {
103 void *txbuf = NULL, *rxbuf = NULL;
104 struct spi_transfer tr[2] = {};
105 u8 *headerbuf;
106 int ret;
107
108 headerbuf = kmalloc(1, GFP_KERNEL);
109 if (!headerbuf)
110 return -ENOMEM;
111
112 headerbuf[0] = header;
113 tr[0].tx_buf = headerbuf;
114 tr[0].len = 1;
115
116 /* Stack allocated tx? */
117 if (tx && len <= 32) {
118 txbuf = kmemdup(tx, len, GFP_KERNEL);
119 if (!txbuf) {
120 ret = -ENOMEM;
121 goto out_free;
122 }
123 }
124
125 if (rx) {
126 rxbuf = kmalloc(len, GFP_KERNEL);
127 if (!rxbuf) {
128 ret = -ENOMEM;
129 goto out_free;
130 }
131 }
132
133 tr[1].tx_buf = txbuf ? txbuf : tx;
134 tr[1].rx_buf = rxbuf;
135 tr[1].len = len;
136
137 ndelay(80);
138 ret = spi_sync_transfer(spi, tr, 2);
139 if (rx && !ret)
140 memcpy(rx, rxbuf, len);
141
142 out_free:
143 kfree(headerbuf);
144 kfree(txbuf);
145 kfree(rxbuf);
146
147 return ret;
148 }
149
repaper_write_buf(struct spi_device * spi,u8 reg,const u8 * buf,size_t len)150 static int repaper_write_buf(struct spi_device *spi, u8 reg,
151 const u8 *buf, size_t len)
152 {
153 int ret;
154
155 ret = repaper_spi_transfer(spi, 0x70, ®, NULL, 1);
156 if (ret)
157 return ret;
158
159 return repaper_spi_transfer(spi, 0x72, buf, NULL, len);
160 }
161
repaper_write_val(struct spi_device * spi,u8 reg,u8 val)162 static int repaper_write_val(struct spi_device *spi, u8 reg, u8 val)
163 {
164 return repaper_write_buf(spi, reg, &val, 1);
165 }
166
repaper_read_val(struct spi_device * spi,u8 reg)167 static int repaper_read_val(struct spi_device *spi, u8 reg)
168 {
169 int ret;
170 u8 val;
171
172 ret = repaper_spi_transfer(spi, 0x70, ®, NULL, 1);
173 if (ret)
174 return ret;
175
176 ret = repaper_spi_transfer(spi, 0x73, NULL, &val, 1);
177
178 return ret ? ret : val;
179 }
180
repaper_read_id(struct spi_device * spi)181 static int repaper_read_id(struct spi_device *spi)
182 {
183 int ret;
184 u8 id;
185
186 ret = repaper_spi_transfer(spi, 0x71, NULL, &id, 1);
187
188 return ret ? ret : id;
189 }
190
repaper_spi_mosi_low(struct spi_device * spi)191 static void repaper_spi_mosi_low(struct spi_device *spi)
192 {
193 const u8 buf[1] = { 0 };
194
195 spi_write(spi, buf, 1);
196 }
197
198 /* pixels on display are numbered from 1 so even is actually bits 1,3,5,... */
repaper_even_pixels(struct repaper_epd * epd,u8 ** pp,const u8 * data,u8 fixed_value,const u8 * mask,enum repaper_stage stage)199 static void repaper_even_pixels(struct repaper_epd *epd, u8 **pp,
200 const u8 *data, u8 fixed_value, const u8 *mask,
201 enum repaper_stage stage)
202 {
203 unsigned int b;
204
205 for (b = 0; b < (epd->width / 8); b++) {
206 if (data) {
207 u8 pixels = data[b] & 0xaa;
208 u8 pixel_mask = 0xff;
209 u8 p1, p2, p3, p4;
210
211 if (mask) {
212 pixel_mask = (mask[b] ^ pixels) & 0xaa;
213 pixel_mask |= pixel_mask >> 1;
214 }
215
216 switch (stage) {
217 case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
218 pixels = 0xaa | ((pixels ^ 0xaa) >> 1);
219 break;
220 case REPAPER_WHITE: /* B -> N, W -> W (Current) */
221 pixels = 0x55 + ((pixels ^ 0xaa) >> 1);
222 break;
223 case REPAPER_INVERSE: /* B -> N, W -> B (New) */
224 pixels = 0x55 | (pixels ^ 0xaa);
225 break;
226 case REPAPER_NORMAL: /* B -> B, W -> W (New) */
227 pixels = 0xaa | (pixels >> 1);
228 break;
229 }
230
231 pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
232 p1 = (pixels >> 6) & 0x03;
233 p2 = (pixels >> 4) & 0x03;
234 p3 = (pixels >> 2) & 0x03;
235 p4 = (pixels >> 0) & 0x03;
236 pixels = (p1 << 0) | (p2 << 2) | (p3 << 4) | (p4 << 6);
237 *(*pp)++ = pixels;
238 } else {
239 *(*pp)++ = fixed_value;
240 }
241 }
242 }
243
244 /* pixels on display are numbered from 1 so odd is actually bits 0,2,4,... */
repaper_odd_pixels(struct repaper_epd * epd,u8 ** pp,const u8 * data,u8 fixed_value,const u8 * mask,enum repaper_stage stage)245 static void repaper_odd_pixels(struct repaper_epd *epd, u8 **pp,
246 const u8 *data, u8 fixed_value, const u8 *mask,
247 enum repaper_stage stage)
248 {
249 unsigned int b;
250
251 for (b = epd->width / 8; b > 0; b--) {
252 if (data) {
253 u8 pixels = data[b - 1] & 0x55;
254 u8 pixel_mask = 0xff;
255
256 if (mask) {
257 pixel_mask = (mask[b - 1] ^ pixels) & 0x55;
258 pixel_mask |= pixel_mask << 1;
259 }
260
261 switch (stage) {
262 case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
263 pixels = 0xaa | (pixels ^ 0x55);
264 break;
265 case REPAPER_WHITE: /* B -> N, W -> W (Current) */
266 pixels = 0x55 + (pixels ^ 0x55);
267 break;
268 case REPAPER_INVERSE: /* B -> N, W -> B (New) */
269 pixels = 0x55 | ((pixels ^ 0x55) << 1);
270 break;
271 case REPAPER_NORMAL: /* B -> B, W -> W (New) */
272 pixels = 0xaa | pixels;
273 break;
274 }
275
276 pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
277 *(*pp)++ = pixels;
278 } else {
279 *(*pp)++ = fixed_value;
280 }
281 }
282 }
283
284 /* interleave bits: (byte)76543210 -> (16 bit).7.6.5.4.3.2.1 */
repaper_interleave_bits(u16 value)285 static inline u16 repaper_interleave_bits(u16 value)
286 {
287 value = (value | (value << 4)) & 0x0f0f;
288 value = (value | (value << 2)) & 0x3333;
289 value = (value | (value << 1)) & 0x5555;
290
291 return value;
292 }
293
294 /* pixels on display are numbered from 1 */
repaper_all_pixels(struct repaper_epd * epd,u8 ** pp,const u8 * data,u8 fixed_value,const u8 * mask,enum repaper_stage stage)295 static void repaper_all_pixels(struct repaper_epd *epd, u8 **pp,
296 const u8 *data, u8 fixed_value, const u8 *mask,
297 enum repaper_stage stage)
298 {
299 unsigned int b;
300
301 for (b = epd->width / 8; b > 0; b--) {
302 if (data) {
303 u16 pixels = repaper_interleave_bits(data[b - 1]);
304 u16 pixel_mask = 0xffff;
305
306 if (mask) {
307 pixel_mask = repaper_interleave_bits(mask[b - 1]);
308
309 pixel_mask = (pixel_mask ^ pixels) & 0x5555;
310 pixel_mask |= pixel_mask << 1;
311 }
312
313 switch (stage) {
314 case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
315 pixels = 0xaaaa | (pixels ^ 0x5555);
316 break;
317 case REPAPER_WHITE: /* B -> N, W -> W (Current) */
318 pixels = 0x5555 + (pixels ^ 0x5555);
319 break;
320 case REPAPER_INVERSE: /* B -> N, W -> B (New) */
321 pixels = 0x5555 | ((pixels ^ 0x5555) << 1);
322 break;
323 case REPAPER_NORMAL: /* B -> B, W -> W (New) */
324 pixels = 0xaaaa | pixels;
325 break;
326 }
327
328 pixels = (pixels & pixel_mask) | (~pixel_mask & 0x5555);
329 *(*pp)++ = pixels >> 8;
330 *(*pp)++ = pixels;
331 } else {
332 *(*pp)++ = fixed_value;
333 *(*pp)++ = fixed_value;
334 }
335 }
336 }
337
338 /* output one line of scan and data bytes to the display */
repaper_one_line(struct repaper_epd * epd,unsigned int line,const u8 * data,u8 fixed_value,const u8 * mask,enum repaper_stage stage)339 static void repaper_one_line(struct repaper_epd *epd, unsigned int line,
340 const u8 *data, u8 fixed_value, const u8 *mask,
341 enum repaper_stage stage)
342 {
343 u8 *p = epd->line_buffer;
344 unsigned int b;
345
346 repaper_spi_mosi_low(epd->spi);
347
348 if (epd->pre_border_byte)
349 *p++ = 0x00;
350
351 if (epd->middle_scan) {
352 /* data bytes */
353 repaper_odd_pixels(epd, &p, data, fixed_value, mask, stage);
354
355 /* scan line */
356 for (b = epd->bytes_per_scan; b > 0; b--) {
357 if (line / 4 == b - 1)
358 *p++ = 0x03 << (2 * (line & 0x03));
359 else
360 *p++ = 0x00;
361 }
362
363 /* data bytes */
364 repaper_even_pixels(epd, &p, data, fixed_value, mask, stage);
365 } else {
366 /*
367 * even scan line, but as lines on display are numbered from 1,
368 * line: 1,3,5,...
369 */
370 for (b = 0; b < epd->bytes_per_scan; b++) {
371 if (0 != (line & 0x01) && line / 8 == b)
372 *p++ = 0xc0 >> (line & 0x06);
373 else
374 *p++ = 0x00;
375 }
376
377 /* data bytes */
378 repaper_all_pixels(epd, &p, data, fixed_value, mask, stage);
379
380 /*
381 * odd scan line, but as lines on display are numbered from 1,
382 * line: 0,2,4,6,...
383 */
384 for (b = epd->bytes_per_scan; b > 0; b--) {
385 if (0 == (line & 0x01) && line / 8 == b - 1)
386 *p++ = 0x03 << (line & 0x06);
387 else
388 *p++ = 0x00;
389 }
390 }
391
392 switch (epd->border_byte) {
393 case REPAPER_BORDER_BYTE_NONE:
394 break;
395
396 case REPAPER_BORDER_BYTE_ZERO:
397 *p++ = 0x00;
398 break;
399
400 case REPAPER_BORDER_BYTE_SET:
401 switch (stage) {
402 case REPAPER_COMPENSATE:
403 case REPAPER_WHITE:
404 case REPAPER_INVERSE:
405 *p++ = 0x00;
406 break;
407 case REPAPER_NORMAL:
408 *p++ = 0xaa;
409 break;
410 }
411 break;
412 }
413
414 repaper_write_buf(epd->spi, 0x0a, epd->line_buffer,
415 p - epd->line_buffer);
416
417 /* Output data to panel */
418 repaper_write_val(epd->spi, 0x02, 0x07);
419
420 repaper_spi_mosi_low(epd->spi);
421 }
422
repaper_frame_fixed(struct repaper_epd * epd,u8 fixed_value,enum repaper_stage stage)423 static void repaper_frame_fixed(struct repaper_epd *epd, u8 fixed_value,
424 enum repaper_stage stage)
425 {
426 unsigned int line;
427
428 for (line = 0; line < epd->height; line++)
429 repaper_one_line(epd, line, NULL, fixed_value, NULL, stage);
430 }
431
repaper_frame_data(struct repaper_epd * epd,const u8 * image,const u8 * mask,enum repaper_stage stage)432 static void repaper_frame_data(struct repaper_epd *epd, const u8 *image,
433 const u8 *mask, enum repaper_stage stage)
434 {
435 unsigned int line;
436
437 if (!mask) {
438 for (line = 0; line < epd->height; line++) {
439 repaper_one_line(epd, line,
440 &image[line * (epd->width / 8)],
441 0, NULL, stage);
442 }
443 } else {
444 for (line = 0; line < epd->height; line++) {
445 size_t n = line * epd->width / 8;
446
447 repaper_one_line(epd, line, &image[n], 0, &mask[n],
448 stage);
449 }
450 }
451 }
452
repaper_frame_fixed_repeat(struct repaper_epd * epd,u8 fixed_value,enum repaper_stage stage)453 static void repaper_frame_fixed_repeat(struct repaper_epd *epd, u8 fixed_value,
454 enum repaper_stage stage)
455 {
456 u64 start = local_clock();
457 u64 end = start + (epd->factored_stage_time * 1000 * 1000);
458
459 do {
460 repaper_frame_fixed(epd, fixed_value, stage);
461 } while (local_clock() < end);
462 }
463
repaper_frame_data_repeat(struct repaper_epd * epd,const u8 * image,const u8 * mask,enum repaper_stage stage)464 static void repaper_frame_data_repeat(struct repaper_epd *epd, const u8 *image,
465 const u8 *mask, enum repaper_stage stage)
466 {
467 u64 start = local_clock();
468 u64 end = start + (epd->factored_stage_time * 1000 * 1000);
469
470 do {
471 repaper_frame_data(epd, image, mask, stage);
472 } while (local_clock() < end);
473 }
474
repaper_get_temperature(struct repaper_epd * epd)475 static void repaper_get_temperature(struct repaper_epd *epd)
476 {
477 int ret, temperature = 0;
478 unsigned int factor10x;
479
480 if (!epd->thermal)
481 return;
482
483 ret = thermal_zone_get_temp(epd->thermal, &temperature);
484 if (ret) {
485 DRM_DEV_ERROR(&epd->spi->dev, "Failed to get temperature (%d)\n", ret);
486 return;
487 }
488
489 temperature /= 1000;
490
491 if (temperature <= -10)
492 factor10x = 170;
493 else if (temperature <= -5)
494 factor10x = 120;
495 else if (temperature <= 5)
496 factor10x = 80;
497 else if (temperature <= 10)
498 factor10x = 40;
499 else if (temperature <= 15)
500 factor10x = 30;
501 else if (temperature <= 20)
502 factor10x = 20;
503 else if (temperature <= 40)
504 factor10x = 10;
505 else
506 factor10x = 7;
507
508 epd->factored_stage_time = epd->stage_time * factor10x / 10;
509 }
510
repaper_fb_dirty(struct drm_framebuffer * fb)511 static int repaper_fb_dirty(struct drm_framebuffer *fb)
512 {
513 struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
514 struct repaper_epd *epd = drm_to_epd(fb->dev);
515 struct drm_rect clip;
516 int idx, ret = 0;
517 u8 *buf = NULL;
518
519 if (!drm_dev_enter(fb->dev, &idx))
520 return -ENODEV;
521
522 /* repaper can't do partial updates */
523 clip.x1 = 0;
524 clip.x2 = fb->width;
525 clip.y1 = 0;
526 clip.y2 = fb->height;
527
528 repaper_get_temperature(epd);
529
530 DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
531 epd->factored_stage_time);
532
533 buf = kmalloc_array(fb->width, fb->height, GFP_KERNEL);
534 if (!buf) {
535 ret = -ENOMEM;
536 goto out_exit;
537 }
538
539 ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
540 if (ret)
541 goto out_free;
542
543 drm_fb_xrgb8888_to_mono(buf, 0, cma_obj->vaddr, fb, &clip);
544
545 drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
546
547 if (epd->partial) {
548 repaper_frame_data_repeat(epd, buf, epd->current_frame,
549 REPAPER_NORMAL);
550 } else if (epd->cleared) {
551 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
552 REPAPER_COMPENSATE);
553 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
554 REPAPER_WHITE);
555 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
556 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
557
558 epd->partial = true;
559 } else {
560 /* Clear display (anything -> white) */
561 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_COMPENSATE);
562 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_WHITE);
563 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_INVERSE);
564 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_NORMAL);
565
566 /* Assuming a clear (white) screen output an image */
567 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_COMPENSATE);
568 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_WHITE);
569 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
570 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
571
572 epd->cleared = true;
573 epd->partial = true;
574 }
575
576 memcpy(epd->current_frame, buf, fb->width * fb->height / 8);
577
578 /*
579 * An extra frame write is needed if pixels are set in the bottom line,
580 * or else grey lines rises up from the pixels
581 */
582 if (epd->pre_border_byte) {
583 unsigned int x;
584
585 for (x = 0; x < (fb->width / 8); x++)
586 if (buf[x + (fb->width * (fb->height - 1) / 8)]) {
587 repaper_frame_data_repeat(epd, buf,
588 epd->current_frame,
589 REPAPER_NORMAL);
590 break;
591 }
592 }
593
594 out_free:
595 kfree(buf);
596 out_exit:
597 drm_dev_exit(idx);
598
599 return ret;
600 }
601
power_off(struct repaper_epd * epd)602 static void power_off(struct repaper_epd *epd)
603 {
604 /* Turn off power and all signals */
605 gpiod_set_value_cansleep(epd->reset, 0);
606 gpiod_set_value_cansleep(epd->panel_on, 0);
607 if (epd->border)
608 gpiod_set_value_cansleep(epd->border, 0);
609
610 /* Ensure SPI MOSI and CLOCK are Low before CS Low */
611 repaper_spi_mosi_low(epd->spi);
612
613 /* Discharge pulse */
614 gpiod_set_value_cansleep(epd->discharge, 1);
615 msleep(150);
616 gpiod_set_value_cansleep(epd->discharge, 0);
617 }
618
repaper_pipe_enable(struct drm_simple_display_pipe * pipe,struct drm_crtc_state * crtc_state,struct drm_plane_state * plane_state)619 static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
620 struct drm_crtc_state *crtc_state,
621 struct drm_plane_state *plane_state)
622 {
623 struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
624 struct spi_device *spi = epd->spi;
625 struct device *dev = &spi->dev;
626 bool dc_ok = false;
627 int i, ret, idx;
628
629 if (!drm_dev_enter(pipe->crtc.dev, &idx))
630 return;
631
632 DRM_DEBUG_DRIVER("\n");
633
634 /* Power up sequence */
635 gpiod_set_value_cansleep(epd->reset, 0);
636 gpiod_set_value_cansleep(epd->panel_on, 0);
637 gpiod_set_value_cansleep(epd->discharge, 0);
638 if (epd->border)
639 gpiod_set_value_cansleep(epd->border, 0);
640 repaper_spi_mosi_low(spi);
641 usleep_range(5000, 10000);
642
643 gpiod_set_value_cansleep(epd->panel_on, 1);
644 /*
645 * This delay comes from the repaper.org userspace driver, it's not
646 * mentioned in the datasheet.
647 */
648 usleep_range(10000, 15000);
649 gpiod_set_value_cansleep(epd->reset, 1);
650 if (epd->border)
651 gpiod_set_value_cansleep(epd->border, 1);
652 usleep_range(5000, 10000);
653 gpiod_set_value_cansleep(epd->reset, 0);
654 usleep_range(5000, 10000);
655 gpiod_set_value_cansleep(epd->reset, 1);
656 usleep_range(5000, 10000);
657
658 /* Wait for COG to become ready */
659 for (i = 100; i > 0; i--) {
660 if (!gpiod_get_value_cansleep(epd->busy))
661 break;
662
663 usleep_range(10, 100);
664 }
665
666 if (!i) {
667 DRM_DEV_ERROR(dev, "timeout waiting for panel to become ready.\n");
668 power_off(epd);
669 goto out_exit;
670 }
671
672 repaper_read_id(spi);
673 ret = repaper_read_id(spi);
674 if (ret != REPAPER_RID_G2_COG_ID) {
675 if (ret < 0)
676 dev_err(dev, "failed to read chip (%d)\n", ret);
677 else
678 dev_err(dev, "wrong COG ID 0x%02x\n", ret);
679 power_off(epd);
680 goto out_exit;
681 }
682
683 /* Disable OE */
684 repaper_write_val(spi, 0x02, 0x40);
685
686 ret = repaper_read_val(spi, 0x0f);
687 if (ret < 0 || !(ret & 0x80)) {
688 if (ret < 0)
689 DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
690 else
691 DRM_DEV_ERROR(dev, "panel is reported broken\n");
692 power_off(epd);
693 goto out_exit;
694 }
695
696 /* Power saving mode */
697 repaper_write_val(spi, 0x0b, 0x02);
698 /* Channel select */
699 repaper_write_buf(spi, 0x01, epd->channel_select, 8);
700 /* High power mode osc */
701 repaper_write_val(spi, 0x07, 0xd1);
702 /* Power setting */
703 repaper_write_val(spi, 0x08, 0x02);
704 /* Vcom level */
705 repaper_write_val(spi, 0x09, 0xc2);
706 /* Power setting */
707 repaper_write_val(spi, 0x04, 0x03);
708 /* Driver latch on */
709 repaper_write_val(spi, 0x03, 0x01);
710 /* Driver latch off */
711 repaper_write_val(spi, 0x03, 0x00);
712 usleep_range(5000, 10000);
713
714 /* Start chargepump */
715 for (i = 0; i < 4; ++i) {
716 /* Charge pump positive voltage on - VGH/VDL on */
717 repaper_write_val(spi, 0x05, 0x01);
718 msleep(240);
719
720 /* Charge pump negative voltage on - VGL/VDL on */
721 repaper_write_val(spi, 0x05, 0x03);
722 msleep(40);
723
724 /* Charge pump Vcom on - Vcom driver on */
725 repaper_write_val(spi, 0x05, 0x0f);
726 msleep(40);
727
728 /* check DC/DC */
729 ret = repaper_read_val(spi, 0x0f);
730 if (ret < 0) {
731 DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
732 power_off(epd);
733 goto out_exit;
734 }
735
736 if (ret & 0x40) {
737 dc_ok = true;
738 break;
739 }
740 }
741
742 if (!dc_ok) {
743 DRM_DEV_ERROR(dev, "dc/dc failed\n");
744 power_off(epd);
745 goto out_exit;
746 }
747
748 /*
749 * Output enable to disable
750 * The userspace driver sets this to 0x04, but the datasheet says 0x06
751 */
752 repaper_write_val(spi, 0x02, 0x04);
753
754 epd->partial = false;
755 out_exit:
756 drm_dev_exit(idx);
757 }
758
repaper_pipe_disable(struct drm_simple_display_pipe * pipe)759 static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
760 {
761 struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
762 struct spi_device *spi = epd->spi;
763 unsigned int line;
764
765 /*
766 * This callback is not protected by drm_dev_enter/exit since we want to
767 * turn off the display on regular driver unload. It's highly unlikely
768 * that the underlying SPI controller is gone should this be called after
769 * unplug.
770 */
771
772 DRM_DEBUG_DRIVER("\n");
773
774 /* Nothing frame */
775 for (line = 0; line < epd->height; line++)
776 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
777 REPAPER_COMPENSATE);
778
779 /* 2.7" */
780 if (epd->border) {
781 /* Dummy line */
782 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
783 REPAPER_COMPENSATE);
784 msleep(25);
785 gpiod_set_value_cansleep(epd->border, 0);
786 msleep(200);
787 gpiod_set_value_cansleep(epd->border, 1);
788 } else {
789 /* Border dummy line */
790 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
791 REPAPER_NORMAL);
792 msleep(200);
793 }
794
795 /* not described in datasheet */
796 repaper_write_val(spi, 0x0b, 0x00);
797 /* Latch reset turn on */
798 repaper_write_val(spi, 0x03, 0x01);
799 /* Power off charge pump Vcom */
800 repaper_write_val(spi, 0x05, 0x03);
801 /* Power off charge pump neg voltage */
802 repaper_write_val(spi, 0x05, 0x01);
803 msleep(120);
804 /* Discharge internal */
805 repaper_write_val(spi, 0x04, 0x80);
806 /* turn off all charge pumps */
807 repaper_write_val(spi, 0x05, 0x00);
808 /* Turn off osc */
809 repaper_write_val(spi, 0x07, 0x01);
810 msleep(50);
811
812 power_off(epd);
813 }
814
repaper_pipe_update(struct drm_simple_display_pipe * pipe,struct drm_plane_state * old_state)815 static void repaper_pipe_update(struct drm_simple_display_pipe *pipe,
816 struct drm_plane_state *old_state)
817 {
818 struct drm_plane_state *state = pipe->plane.state;
819 struct drm_rect rect;
820
821 if (!pipe->crtc.state->active)
822 return;
823
824 if (drm_atomic_helper_damage_merged(old_state, state, &rect))
825 repaper_fb_dirty(state->fb);
826 }
827
828 static const struct drm_simple_display_pipe_funcs repaper_pipe_funcs = {
829 .enable = repaper_pipe_enable,
830 .disable = repaper_pipe_disable,
831 .update = repaper_pipe_update,
832 };
833
repaper_connector_get_modes(struct drm_connector * connector)834 static int repaper_connector_get_modes(struct drm_connector *connector)
835 {
836 struct repaper_epd *epd = drm_to_epd(connector->dev);
837 struct drm_display_mode *mode;
838
839 mode = drm_mode_duplicate(connector->dev, epd->mode);
840 if (!mode) {
841 DRM_ERROR("Failed to duplicate mode\n");
842 return 0;
843 }
844
845 drm_mode_set_name(mode);
846 mode->type |= DRM_MODE_TYPE_PREFERRED;
847 drm_mode_probed_add(connector, mode);
848
849 connector->display_info.width_mm = mode->width_mm;
850 connector->display_info.height_mm = mode->height_mm;
851
852 return 1;
853 }
854
855 static const struct drm_connector_helper_funcs repaper_connector_hfuncs = {
856 .get_modes = repaper_connector_get_modes,
857 };
858
859 static const struct drm_connector_funcs repaper_connector_funcs = {
860 .reset = drm_atomic_helper_connector_reset,
861 .fill_modes = drm_helper_probe_single_connector_modes,
862 .destroy = drm_connector_cleanup,
863 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
864 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
865 };
866
867 static const struct drm_mode_config_funcs repaper_mode_config_funcs = {
868 .fb_create = drm_gem_fb_create_with_dirty,
869 .atomic_check = drm_atomic_helper_check,
870 .atomic_commit = drm_atomic_helper_commit,
871 };
872
873 static const uint32_t repaper_formats[] = {
874 DRM_FORMAT_XRGB8888,
875 };
876
877 static const struct drm_display_mode repaper_e1144cs021_mode = {
878 DRM_SIMPLE_MODE(128, 96, 29, 22),
879 };
880
881 static const u8 repaper_e1144cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
882 0x00, 0x0f, 0xff, 0x00 };
883
884 static const struct drm_display_mode repaper_e1190cs021_mode = {
885 DRM_SIMPLE_MODE(144, 128, 36, 32),
886 };
887
888 static const u8 repaper_e1190cs021_cs[] = { 0x00, 0x00, 0x00, 0x03,
889 0xfc, 0x00, 0x00, 0xff };
890
891 static const struct drm_display_mode repaper_e2200cs021_mode = {
892 DRM_SIMPLE_MODE(200, 96, 46, 22),
893 };
894
895 static const u8 repaper_e2200cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
896 0x01, 0xff, 0xe0, 0x00 };
897
898 static const struct drm_display_mode repaper_e2271cs021_mode = {
899 DRM_SIMPLE_MODE(264, 176, 57, 38),
900 };
901
902 static const u8 repaper_e2271cs021_cs[] = { 0x00, 0x00, 0x00, 0x7f,
903 0xff, 0xfe, 0x00, 0x00 };
904
905 DEFINE_DRM_GEM_CMA_FOPS(repaper_fops);
906
907 static const struct drm_driver repaper_driver = {
908 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
909 .fops = &repaper_fops,
910 DRM_GEM_CMA_DRIVER_OPS_VMAP,
911 .name = "repaper",
912 .desc = "Pervasive Displays RePaper e-ink panels",
913 .date = "20170405",
914 .major = 1,
915 .minor = 0,
916 };
917
918 static const struct of_device_id repaper_of_match[] = {
919 { .compatible = "pervasive,e1144cs021", .data = (void *)E1144CS021 },
920 { .compatible = "pervasive,e1190cs021", .data = (void *)E1190CS021 },
921 { .compatible = "pervasive,e2200cs021", .data = (void *)E2200CS021 },
922 { .compatible = "pervasive,e2271cs021", .data = (void *)E2271CS021 },
923 {},
924 };
925 MODULE_DEVICE_TABLE(of, repaper_of_match);
926
927 static const struct spi_device_id repaper_id[] = {
928 { "e1144cs021", E1144CS021 },
929 { "e1190cs021", E1190CS021 },
930 { "e2200cs021", E2200CS021 },
931 { "e2271cs021", E2271CS021 },
932 { },
933 };
934 MODULE_DEVICE_TABLE(spi, repaper_id);
935
repaper_probe(struct spi_device * spi)936 static int repaper_probe(struct spi_device *spi)
937 {
938 const struct drm_display_mode *mode;
939 const struct spi_device_id *spi_id;
940 struct device *dev = &spi->dev;
941 enum repaper_model model;
942 const char *thermal_zone;
943 struct repaper_epd *epd;
944 size_t line_buffer_size;
945 struct drm_device *drm;
946 const void *match;
947 int ret;
948
949 match = device_get_match_data(dev);
950 if (match) {
951 model = (enum repaper_model)match;
952 } else {
953 spi_id = spi_get_device_id(spi);
954 model = (enum repaper_model)spi_id->driver_data;
955 }
956
957 /* The SPI device is used to allocate dma memory */
958 if (!dev->coherent_dma_mask) {
959 ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
960 if (ret) {
961 dev_warn(dev, "Failed to set dma mask %d\n", ret);
962 return ret;
963 }
964 }
965
966 epd = devm_drm_dev_alloc(dev, &repaper_driver,
967 struct repaper_epd, drm);
968 if (IS_ERR(epd))
969 return PTR_ERR(epd);
970
971 drm = &epd->drm;
972
973 ret = drmm_mode_config_init(drm);
974 if (ret)
975 return ret;
976 drm->mode_config.funcs = &repaper_mode_config_funcs;
977
978 epd->spi = spi;
979
980 epd->panel_on = devm_gpiod_get(dev, "panel-on", GPIOD_OUT_LOW);
981 if (IS_ERR(epd->panel_on)) {
982 ret = PTR_ERR(epd->panel_on);
983 if (ret != -EPROBE_DEFER)
984 DRM_DEV_ERROR(dev, "Failed to get gpio 'panel-on'\n");
985 return ret;
986 }
987
988 epd->discharge = devm_gpiod_get(dev, "discharge", GPIOD_OUT_LOW);
989 if (IS_ERR(epd->discharge)) {
990 ret = PTR_ERR(epd->discharge);
991 if (ret != -EPROBE_DEFER)
992 DRM_DEV_ERROR(dev, "Failed to get gpio 'discharge'\n");
993 return ret;
994 }
995
996 epd->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
997 if (IS_ERR(epd->reset)) {
998 ret = PTR_ERR(epd->reset);
999 if (ret != -EPROBE_DEFER)
1000 DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
1001 return ret;
1002 }
1003
1004 epd->busy = devm_gpiod_get(dev, "busy", GPIOD_IN);
1005 if (IS_ERR(epd->busy)) {
1006 ret = PTR_ERR(epd->busy);
1007 if (ret != -EPROBE_DEFER)
1008 DRM_DEV_ERROR(dev, "Failed to get gpio 'busy'\n");
1009 return ret;
1010 }
1011
1012 if (!device_property_read_string(dev, "pervasive,thermal-zone",
1013 &thermal_zone)) {
1014 epd->thermal = thermal_zone_get_zone_by_name(thermal_zone);
1015 if (IS_ERR(epd->thermal)) {
1016 DRM_DEV_ERROR(dev, "Failed to get thermal zone: %s\n", thermal_zone);
1017 return PTR_ERR(epd->thermal);
1018 }
1019 }
1020
1021 switch (model) {
1022 case E1144CS021:
1023 mode = &repaper_e1144cs021_mode;
1024 epd->channel_select = repaper_e1144cs021_cs;
1025 epd->stage_time = 480;
1026 epd->bytes_per_scan = 96 / 4;
1027 epd->middle_scan = true; /* data-scan-data */
1028 epd->pre_border_byte = false;
1029 epd->border_byte = REPAPER_BORDER_BYTE_ZERO;
1030 break;
1031
1032 case E1190CS021:
1033 mode = &repaper_e1190cs021_mode;
1034 epd->channel_select = repaper_e1190cs021_cs;
1035 epd->stage_time = 480;
1036 epd->bytes_per_scan = 128 / 4 / 2;
1037 epd->middle_scan = false; /* scan-data-scan */
1038 epd->pre_border_byte = false;
1039 epd->border_byte = REPAPER_BORDER_BYTE_SET;
1040 break;
1041
1042 case E2200CS021:
1043 mode = &repaper_e2200cs021_mode;
1044 epd->channel_select = repaper_e2200cs021_cs;
1045 epd->stage_time = 480;
1046 epd->bytes_per_scan = 96 / 4;
1047 epd->middle_scan = true; /* data-scan-data */
1048 epd->pre_border_byte = true;
1049 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1050 break;
1051
1052 case E2271CS021:
1053 epd->border = devm_gpiod_get(dev, "border", GPIOD_OUT_LOW);
1054 if (IS_ERR(epd->border)) {
1055 ret = PTR_ERR(epd->border);
1056 if (ret != -EPROBE_DEFER)
1057 DRM_DEV_ERROR(dev, "Failed to get gpio 'border'\n");
1058 return ret;
1059 }
1060
1061 mode = &repaper_e2271cs021_mode;
1062 epd->channel_select = repaper_e2271cs021_cs;
1063 epd->stage_time = 630;
1064 epd->bytes_per_scan = 176 / 4;
1065 epd->middle_scan = true; /* data-scan-data */
1066 epd->pre_border_byte = true;
1067 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1068 break;
1069
1070 default:
1071 return -ENODEV;
1072 }
1073
1074 epd->mode = mode;
1075 epd->width = mode->hdisplay;
1076 epd->height = mode->vdisplay;
1077 epd->factored_stage_time = epd->stage_time;
1078
1079 line_buffer_size = 2 * epd->width / 8 + epd->bytes_per_scan + 2;
1080 epd->line_buffer = devm_kzalloc(dev, line_buffer_size, GFP_KERNEL);
1081 if (!epd->line_buffer)
1082 return -ENOMEM;
1083
1084 epd->current_frame = devm_kzalloc(dev, epd->width * epd->height / 8,
1085 GFP_KERNEL);
1086 if (!epd->current_frame)
1087 return -ENOMEM;
1088
1089 drm->mode_config.min_width = mode->hdisplay;
1090 drm->mode_config.max_width = mode->hdisplay;
1091 drm->mode_config.min_height = mode->vdisplay;
1092 drm->mode_config.max_height = mode->vdisplay;
1093
1094 drm_connector_helper_add(&epd->connector, &repaper_connector_hfuncs);
1095 ret = drm_connector_init(drm, &epd->connector, &repaper_connector_funcs,
1096 DRM_MODE_CONNECTOR_SPI);
1097 if (ret)
1098 return ret;
1099
1100 ret = drm_simple_display_pipe_init(drm, &epd->pipe, &repaper_pipe_funcs,
1101 repaper_formats, ARRAY_SIZE(repaper_formats),
1102 NULL, &epd->connector);
1103 if (ret)
1104 return ret;
1105
1106 drm_mode_config_reset(drm);
1107
1108 ret = drm_dev_register(drm, 0);
1109 if (ret)
1110 return ret;
1111
1112 spi_set_drvdata(spi, drm);
1113
1114 DRM_DEBUG_DRIVER("SPI speed: %uMHz\n", spi->max_speed_hz / 1000000);
1115
1116 drm_fbdev_generic_setup(drm, 0);
1117
1118 return 0;
1119 }
1120
repaper_remove(struct spi_device * spi)1121 static void repaper_remove(struct spi_device *spi)
1122 {
1123 struct drm_device *drm = spi_get_drvdata(spi);
1124
1125 drm_dev_unplug(drm);
1126 drm_atomic_helper_shutdown(drm);
1127 }
1128
repaper_shutdown(struct spi_device * spi)1129 static void repaper_shutdown(struct spi_device *spi)
1130 {
1131 drm_atomic_helper_shutdown(spi_get_drvdata(spi));
1132 }
1133
1134 static struct spi_driver repaper_spi_driver = {
1135 .driver = {
1136 .name = "repaper",
1137 .of_match_table = repaper_of_match,
1138 },
1139 .id_table = repaper_id,
1140 .probe = repaper_probe,
1141 .remove = repaper_remove,
1142 .shutdown = repaper_shutdown,
1143 };
1144 module_spi_driver(repaper_spi_driver);
1145
1146 MODULE_DESCRIPTION("Pervasive Displays RePaper DRM driver");
1147 MODULE_AUTHOR("Noralf Trønnes");
1148 MODULE_LICENSE("GPL");
1149