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/clients/drm_client_setup.h>
25 #include <drm/drm_atomic_helper.h>
26 #include <drm/drm_connector.h>
27 #include <drm/drm_damage_helper.h>
28 #include <drm/drm_drv.h>
29 #include <drm/drm_fb_dma_helper.h>
30 #include <drm/drm_fbdev_dma.h>
31 #include <drm/drm_format_helper.h>
32 #include <drm/drm_framebuffer.h>
33 #include <drm/drm_gem_atomic_helper.h>
34 #include <drm/drm_gem_dma_helper.h>
35 #include <drm/drm_gem_framebuffer_helper.h>
36 #include <drm/drm_managed.h>
37 #include <drm/drm_modes.h>
38 #include <drm/drm_rect.h>
39 #include <drm/drm_probe_helper.h>
40 #include <drm/drm_simple_kms_helper.h>
41
42 #define REPAPER_RID_G2_COG_ID 0x12
43
44 enum repaper_model {
45 /* 0 is reserved to avoid clashing with NULL */
46 E1144CS021 = 1,
47 E1190CS021,
48 E2200CS021,
49 E2271CS021,
50 };
51
52 enum repaper_stage { /* Image pixel -> Display pixel */
53 REPAPER_COMPENSATE, /* B -> W, W -> B (Current Image) */
54 REPAPER_WHITE, /* B -> N, W -> W (Current Image) */
55 REPAPER_INVERSE, /* B -> N, W -> B (New Image) */
56 REPAPER_NORMAL /* B -> B, W -> W (New Image) */
57 };
58
59 enum repaper_epd_border_byte {
60 REPAPER_BORDER_BYTE_NONE,
61 REPAPER_BORDER_BYTE_ZERO,
62 REPAPER_BORDER_BYTE_SET,
63 };
64
65 struct repaper_epd {
66 struct drm_device drm;
67 struct drm_simple_display_pipe pipe;
68 const struct drm_display_mode *mode;
69 struct drm_connector connector;
70 struct spi_device *spi;
71
72 struct gpio_desc *panel_on;
73 struct gpio_desc *border;
74 struct gpio_desc *discharge;
75 struct gpio_desc *reset;
76 struct gpio_desc *busy;
77
78 struct thermal_zone_device *thermal;
79
80 unsigned int height;
81 unsigned int width;
82 unsigned int bytes_per_scan;
83 const u8 *channel_select;
84 unsigned int stage_time;
85 unsigned int factored_stage_time;
86 bool middle_scan;
87 bool pre_border_byte;
88 enum repaper_epd_border_byte border_byte;
89
90 u8 *line_buffer;
91 void *current_frame;
92
93 bool cleared;
94 bool partial;
95 };
96
drm_to_epd(struct drm_device * drm)97 static inline struct repaper_epd *drm_to_epd(struct drm_device *drm)
98 {
99 return container_of(drm, struct repaper_epd, drm);
100 }
101
repaper_spi_transfer(struct spi_device * spi,u8 header,const void * tx,void * rx,size_t len)102 static int repaper_spi_transfer(struct spi_device *spi, u8 header,
103 const void *tx, void *rx, size_t len)
104 {
105 void *txbuf = NULL, *rxbuf = NULL;
106 struct spi_transfer tr[2] = {};
107 u8 *headerbuf;
108 int ret;
109
110 headerbuf = kmalloc(1, GFP_KERNEL);
111 if (!headerbuf)
112 return -ENOMEM;
113
114 headerbuf[0] = header;
115 tr[0].tx_buf = headerbuf;
116 tr[0].len = 1;
117
118 /* Stack allocated tx? */
119 if (tx && len <= 32) {
120 txbuf = kmemdup(tx, len, GFP_KERNEL);
121 if (!txbuf) {
122 ret = -ENOMEM;
123 goto out_free;
124 }
125 }
126
127 if (rx) {
128 rxbuf = kmalloc(len, GFP_KERNEL);
129 if (!rxbuf) {
130 ret = -ENOMEM;
131 goto out_free;
132 }
133 }
134
135 tr[1].tx_buf = txbuf ? txbuf : tx;
136 tr[1].rx_buf = rxbuf;
137 tr[1].len = len;
138
139 ndelay(80);
140 ret = spi_sync_transfer(spi, tr, 2);
141 if (rx && !ret)
142 memcpy(rx, rxbuf, len);
143
144 out_free:
145 kfree(headerbuf);
146 kfree(txbuf);
147 kfree(rxbuf);
148
149 return ret;
150 }
151
repaper_write_buf(struct spi_device * spi,u8 reg,const u8 * buf,size_t len)152 static int repaper_write_buf(struct spi_device *spi, u8 reg,
153 const u8 *buf, size_t len)
154 {
155 int ret;
156
157 ret = repaper_spi_transfer(spi, 0x70, ®, NULL, 1);
158 if (ret)
159 return ret;
160
161 return repaper_spi_transfer(spi, 0x72, buf, NULL, len);
162 }
163
repaper_write_val(struct spi_device * spi,u8 reg,u8 val)164 static int repaper_write_val(struct spi_device *spi, u8 reg, u8 val)
165 {
166 return repaper_write_buf(spi, reg, &val, 1);
167 }
168
repaper_read_val(struct spi_device * spi,u8 reg)169 static int repaper_read_val(struct spi_device *spi, u8 reg)
170 {
171 int ret;
172 u8 val;
173
174 ret = repaper_spi_transfer(spi, 0x70, ®, NULL, 1);
175 if (ret)
176 return ret;
177
178 ret = repaper_spi_transfer(spi, 0x73, NULL, &val, 1);
179
180 return ret ? ret : val;
181 }
182
repaper_read_id(struct spi_device * spi)183 static int repaper_read_id(struct spi_device *spi)
184 {
185 int ret;
186 u8 id;
187
188 ret = repaper_spi_transfer(spi, 0x71, NULL, &id, 1);
189
190 return ret ? ret : id;
191 }
192
repaper_spi_mosi_low(struct spi_device * spi)193 static void repaper_spi_mosi_low(struct spi_device *spi)
194 {
195 const u8 buf[1] = { 0 };
196
197 spi_write(spi, buf, 1);
198 }
199
200 /* 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)201 static void repaper_even_pixels(struct repaper_epd *epd, u8 **pp,
202 const u8 *data, u8 fixed_value, const u8 *mask,
203 enum repaper_stage stage)
204 {
205 unsigned int b;
206
207 for (b = 0; b < (epd->width / 8); b++) {
208 if (data) {
209 u8 pixels = data[b] & 0xaa;
210 u8 pixel_mask = 0xff;
211 u8 p1, p2, p3, p4;
212
213 if (mask) {
214 pixel_mask = (mask[b] ^ pixels) & 0xaa;
215 pixel_mask |= pixel_mask >> 1;
216 }
217
218 switch (stage) {
219 case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
220 pixels = 0xaa | ((pixels ^ 0xaa) >> 1);
221 break;
222 case REPAPER_WHITE: /* B -> N, W -> W (Current) */
223 pixels = 0x55 + ((pixels ^ 0xaa) >> 1);
224 break;
225 case REPAPER_INVERSE: /* B -> N, W -> B (New) */
226 pixels = 0x55 | (pixels ^ 0xaa);
227 break;
228 case REPAPER_NORMAL: /* B -> B, W -> W (New) */
229 pixels = 0xaa | (pixels >> 1);
230 break;
231 }
232
233 pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
234 p1 = (pixels >> 6) & 0x03;
235 p2 = (pixels >> 4) & 0x03;
236 p3 = (pixels >> 2) & 0x03;
237 p4 = (pixels >> 0) & 0x03;
238 pixels = (p1 << 0) | (p2 << 2) | (p3 << 4) | (p4 << 6);
239 *(*pp)++ = pixels;
240 } else {
241 *(*pp)++ = fixed_value;
242 }
243 }
244 }
245
246 /* 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)247 static void repaper_odd_pixels(struct repaper_epd *epd, u8 **pp,
248 const u8 *data, u8 fixed_value, const u8 *mask,
249 enum repaper_stage stage)
250 {
251 unsigned int b;
252
253 for (b = epd->width / 8; b > 0; b--) {
254 if (data) {
255 u8 pixels = data[b - 1] & 0x55;
256 u8 pixel_mask = 0xff;
257
258 if (mask) {
259 pixel_mask = (mask[b - 1] ^ pixels) & 0x55;
260 pixel_mask |= pixel_mask << 1;
261 }
262
263 switch (stage) {
264 case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
265 pixels = 0xaa | (pixels ^ 0x55);
266 break;
267 case REPAPER_WHITE: /* B -> N, W -> W (Current) */
268 pixels = 0x55 + (pixels ^ 0x55);
269 break;
270 case REPAPER_INVERSE: /* B -> N, W -> B (New) */
271 pixels = 0x55 | ((pixels ^ 0x55) << 1);
272 break;
273 case REPAPER_NORMAL: /* B -> B, W -> W (New) */
274 pixels = 0xaa | pixels;
275 break;
276 }
277
278 pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
279 *(*pp)++ = pixels;
280 } else {
281 *(*pp)++ = fixed_value;
282 }
283 }
284 }
285
286 /* interleave bits: (byte)76543210 -> (16 bit).7.6.5.4.3.2.1 */
repaper_interleave_bits(u16 value)287 static inline u16 repaper_interleave_bits(u16 value)
288 {
289 value = (value | (value << 4)) & 0x0f0f;
290 value = (value | (value << 2)) & 0x3333;
291 value = (value | (value << 1)) & 0x5555;
292
293 return value;
294 }
295
296 /* 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)297 static void repaper_all_pixels(struct repaper_epd *epd, u8 **pp,
298 const u8 *data, u8 fixed_value, const u8 *mask,
299 enum repaper_stage stage)
300 {
301 unsigned int b;
302
303 for (b = epd->width / 8; b > 0; b--) {
304 if (data) {
305 u16 pixels = repaper_interleave_bits(data[b - 1]);
306 u16 pixel_mask = 0xffff;
307
308 if (mask) {
309 pixel_mask = repaper_interleave_bits(mask[b - 1]);
310
311 pixel_mask = (pixel_mask ^ pixels) & 0x5555;
312 pixel_mask |= pixel_mask << 1;
313 }
314
315 switch (stage) {
316 case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
317 pixels = 0xaaaa | (pixels ^ 0x5555);
318 break;
319 case REPAPER_WHITE: /* B -> N, W -> W (Current) */
320 pixels = 0x5555 + (pixels ^ 0x5555);
321 break;
322 case REPAPER_INVERSE: /* B -> N, W -> B (New) */
323 pixels = 0x5555 | ((pixels ^ 0x5555) << 1);
324 break;
325 case REPAPER_NORMAL: /* B -> B, W -> W (New) */
326 pixels = 0xaaaa | pixels;
327 break;
328 }
329
330 pixels = (pixels & pixel_mask) | (~pixel_mask & 0x5555);
331 *(*pp)++ = pixels >> 8;
332 *(*pp)++ = pixels;
333 } else {
334 *(*pp)++ = fixed_value;
335 *(*pp)++ = fixed_value;
336 }
337 }
338 }
339
340 /* 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)341 static void repaper_one_line(struct repaper_epd *epd, unsigned int line,
342 const u8 *data, u8 fixed_value, const u8 *mask,
343 enum repaper_stage stage)
344 {
345 u8 *p = epd->line_buffer;
346 unsigned int b;
347
348 repaper_spi_mosi_low(epd->spi);
349
350 if (epd->pre_border_byte)
351 *p++ = 0x00;
352
353 if (epd->middle_scan) {
354 /* data bytes */
355 repaper_odd_pixels(epd, &p, data, fixed_value, mask, stage);
356
357 /* scan line */
358 for (b = epd->bytes_per_scan; b > 0; b--) {
359 if (line / 4 == b - 1)
360 *p++ = 0x03 << (2 * (line & 0x03));
361 else
362 *p++ = 0x00;
363 }
364
365 /* data bytes */
366 repaper_even_pixels(epd, &p, data, fixed_value, mask, stage);
367 } else {
368 /*
369 * even scan line, but as lines on display are numbered from 1,
370 * line: 1,3,5,...
371 */
372 for (b = 0; b < epd->bytes_per_scan; b++) {
373 if (0 != (line & 0x01) && line / 8 == b)
374 *p++ = 0xc0 >> (line & 0x06);
375 else
376 *p++ = 0x00;
377 }
378
379 /* data bytes */
380 repaper_all_pixels(epd, &p, data, fixed_value, mask, stage);
381
382 /*
383 * odd scan line, but as lines on display are numbered from 1,
384 * line: 0,2,4,6,...
385 */
386 for (b = epd->bytes_per_scan; b > 0; b--) {
387 if (0 == (line & 0x01) && line / 8 == b - 1)
388 *p++ = 0x03 << (line & 0x06);
389 else
390 *p++ = 0x00;
391 }
392 }
393
394 switch (epd->border_byte) {
395 case REPAPER_BORDER_BYTE_NONE:
396 break;
397
398 case REPAPER_BORDER_BYTE_ZERO:
399 *p++ = 0x00;
400 break;
401
402 case REPAPER_BORDER_BYTE_SET:
403 switch (stage) {
404 case REPAPER_COMPENSATE:
405 case REPAPER_WHITE:
406 case REPAPER_INVERSE:
407 *p++ = 0x00;
408 break;
409 case REPAPER_NORMAL:
410 *p++ = 0xaa;
411 break;
412 }
413 break;
414 }
415
416 repaper_write_buf(epd->spi, 0x0a, epd->line_buffer,
417 p - epd->line_buffer);
418
419 /* Output data to panel */
420 repaper_write_val(epd->spi, 0x02, 0x07);
421
422 repaper_spi_mosi_low(epd->spi);
423 }
424
repaper_frame_fixed(struct repaper_epd * epd,u8 fixed_value,enum repaper_stage stage)425 static void repaper_frame_fixed(struct repaper_epd *epd, u8 fixed_value,
426 enum repaper_stage stage)
427 {
428 unsigned int line;
429
430 for (line = 0; line < epd->height; line++)
431 repaper_one_line(epd, line, NULL, fixed_value, NULL, stage);
432 }
433
repaper_frame_data(struct repaper_epd * epd,const u8 * image,const u8 * mask,enum repaper_stage stage)434 static void repaper_frame_data(struct repaper_epd *epd, const u8 *image,
435 const u8 *mask, enum repaper_stage stage)
436 {
437 unsigned int line;
438
439 if (!mask) {
440 for (line = 0; line < epd->height; line++) {
441 repaper_one_line(epd, line,
442 &image[line * (epd->width / 8)],
443 0, NULL, stage);
444 }
445 } else {
446 for (line = 0; line < epd->height; line++) {
447 size_t n = line * epd->width / 8;
448
449 repaper_one_line(epd, line, &image[n], 0, &mask[n],
450 stage);
451 }
452 }
453 }
454
repaper_frame_fixed_repeat(struct repaper_epd * epd,u8 fixed_value,enum repaper_stage stage)455 static void repaper_frame_fixed_repeat(struct repaper_epd *epd, u8 fixed_value,
456 enum repaper_stage stage)
457 {
458 u64 start = local_clock();
459 u64 end = start + ((u64)epd->factored_stage_time * 1000 * 1000);
460
461 do {
462 repaper_frame_fixed(epd, fixed_value, stage);
463 } while (local_clock() < end);
464 }
465
repaper_frame_data_repeat(struct repaper_epd * epd,const u8 * image,const u8 * mask,enum repaper_stage stage)466 static void repaper_frame_data_repeat(struct repaper_epd *epd, const u8 *image,
467 const u8 *mask, enum repaper_stage stage)
468 {
469 u64 start = local_clock();
470 u64 end = start + ((u64)epd->factored_stage_time * 1000 * 1000);
471
472 do {
473 repaper_frame_data(epd, image, mask, stage);
474 } while (local_clock() < end);
475 }
476
repaper_get_temperature(struct repaper_epd * epd)477 static void repaper_get_temperature(struct repaper_epd *epd)
478 {
479 int ret, temperature = 0;
480 unsigned int factor10x;
481
482 if (!epd->thermal)
483 return;
484
485 ret = thermal_zone_get_temp(epd->thermal, &temperature);
486 if (ret) {
487 DRM_DEV_ERROR(&epd->spi->dev, "Failed to get temperature (%d)\n", ret);
488 return;
489 }
490
491 temperature /= 1000;
492
493 if (temperature <= -10)
494 factor10x = 170;
495 else if (temperature <= -5)
496 factor10x = 120;
497 else if (temperature <= 5)
498 factor10x = 80;
499 else if (temperature <= 10)
500 factor10x = 40;
501 else if (temperature <= 15)
502 factor10x = 30;
503 else if (temperature <= 20)
504 factor10x = 20;
505 else if (temperature <= 40)
506 factor10x = 10;
507 else
508 factor10x = 7;
509
510 epd->factored_stage_time = epd->stage_time * factor10x / 10;
511 }
512
repaper_fb_dirty(struct drm_framebuffer * fb,const struct iosys_map * vmap,struct drm_format_conv_state * fmtcnv_state)513 static int repaper_fb_dirty(struct drm_framebuffer *fb, const struct iosys_map *vmap,
514 struct drm_format_conv_state *fmtcnv_state)
515 {
516 struct repaper_epd *epd = drm_to_epd(fb->dev);
517 unsigned int dst_pitch = 0;
518 struct iosys_map dst;
519 struct drm_rect clip;
520 int idx, ret = 0;
521 u8 *buf = NULL;
522
523 if (!drm_dev_enter(fb->dev, &idx))
524 return -ENODEV;
525
526 /* repaper can't do partial updates */
527 clip.x1 = 0;
528 clip.x2 = fb->width;
529 clip.y1 = 0;
530 clip.y2 = fb->height;
531
532 repaper_get_temperature(epd);
533
534 DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
535 epd->factored_stage_time);
536
537 buf = kmalloc(fb->width * fb->height / 8, GFP_KERNEL);
538 if (!buf) {
539 ret = -ENOMEM;
540 goto out_exit;
541 }
542
543 ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
544 if (ret)
545 goto out_free;
546
547 iosys_map_set_vaddr(&dst, buf);
548 drm_fb_xrgb8888_to_mono(&dst, &dst_pitch, vmap, fb, &clip, fmtcnv_state);
549
550 drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
551
552 if (epd->partial) {
553 repaper_frame_data_repeat(epd, buf, epd->current_frame,
554 REPAPER_NORMAL);
555 } else if (epd->cleared) {
556 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
557 REPAPER_COMPENSATE);
558 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
559 REPAPER_WHITE);
560 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
561 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
562
563 epd->partial = true;
564 } else {
565 /* Clear display (anything -> white) */
566 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_COMPENSATE);
567 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_WHITE);
568 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_INVERSE);
569 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_NORMAL);
570
571 /* Assuming a clear (white) screen output an image */
572 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_COMPENSATE);
573 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_WHITE);
574 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
575 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
576
577 epd->cleared = true;
578 epd->partial = true;
579 }
580
581 memcpy(epd->current_frame, buf, fb->width * fb->height / 8);
582
583 /*
584 * An extra frame write is needed if pixels are set in the bottom line,
585 * or else grey lines rises up from the pixels
586 */
587 if (epd->pre_border_byte) {
588 unsigned int x;
589
590 for (x = 0; x < (fb->width / 8); x++)
591 if (buf[x + (fb->width * (fb->height - 1) / 8)]) {
592 repaper_frame_data_repeat(epd, buf,
593 epd->current_frame,
594 REPAPER_NORMAL);
595 break;
596 }
597 }
598
599 out_free:
600 kfree(buf);
601 out_exit:
602 drm_dev_exit(idx);
603
604 return ret;
605 }
606
power_off(struct repaper_epd * epd)607 static void power_off(struct repaper_epd *epd)
608 {
609 /* Turn off power and all signals */
610 gpiod_set_value_cansleep(epd->reset, 0);
611 gpiod_set_value_cansleep(epd->panel_on, 0);
612 if (epd->border)
613 gpiod_set_value_cansleep(epd->border, 0);
614
615 /* Ensure SPI MOSI and CLOCK are Low before CS Low */
616 repaper_spi_mosi_low(epd->spi);
617
618 /* Discharge pulse */
619 gpiod_set_value_cansleep(epd->discharge, 1);
620 msleep(150);
621 gpiod_set_value_cansleep(epd->discharge, 0);
622 }
623
repaper_pipe_mode_valid(struct drm_simple_display_pipe * pipe,const struct drm_display_mode * mode)624 static enum drm_mode_status repaper_pipe_mode_valid(struct drm_simple_display_pipe *pipe,
625 const struct drm_display_mode *mode)
626 {
627 struct drm_crtc *crtc = &pipe->crtc;
628 struct repaper_epd *epd = drm_to_epd(crtc->dev);
629
630 return drm_crtc_helper_mode_valid_fixed(crtc, mode, epd->mode);
631 }
632
repaper_pipe_enable(struct drm_simple_display_pipe * pipe,struct drm_crtc_state * crtc_state,struct drm_plane_state * plane_state)633 static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
634 struct drm_crtc_state *crtc_state,
635 struct drm_plane_state *plane_state)
636 {
637 struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
638 struct spi_device *spi = epd->spi;
639 struct device *dev = &spi->dev;
640 bool dc_ok = false;
641 int i, ret, idx;
642
643 if (!drm_dev_enter(pipe->crtc.dev, &idx))
644 return;
645
646 DRM_DEBUG_DRIVER("\n");
647
648 /* Power up sequence */
649 gpiod_set_value_cansleep(epd->reset, 0);
650 gpiod_set_value_cansleep(epd->panel_on, 0);
651 gpiod_set_value_cansleep(epd->discharge, 0);
652 if (epd->border)
653 gpiod_set_value_cansleep(epd->border, 0);
654 repaper_spi_mosi_low(spi);
655 usleep_range(5000, 10000);
656
657 gpiod_set_value_cansleep(epd->panel_on, 1);
658 /*
659 * This delay comes from the repaper.org userspace driver, it's not
660 * mentioned in the datasheet.
661 */
662 usleep_range(10000, 15000);
663 gpiod_set_value_cansleep(epd->reset, 1);
664 if (epd->border)
665 gpiod_set_value_cansleep(epd->border, 1);
666 usleep_range(5000, 10000);
667 gpiod_set_value_cansleep(epd->reset, 0);
668 usleep_range(5000, 10000);
669 gpiod_set_value_cansleep(epd->reset, 1);
670 usleep_range(5000, 10000);
671
672 /* Wait for COG to become ready */
673 for (i = 100; i > 0; i--) {
674 if (!gpiod_get_value_cansleep(epd->busy))
675 break;
676
677 usleep_range(10, 100);
678 }
679
680 if (!i) {
681 DRM_DEV_ERROR(dev, "timeout waiting for panel to become ready.\n");
682 power_off(epd);
683 goto out_exit;
684 }
685
686 repaper_read_id(spi);
687 ret = repaper_read_id(spi);
688 if (ret != REPAPER_RID_G2_COG_ID) {
689 if (ret < 0)
690 dev_err(dev, "failed to read chip (%d)\n", ret);
691 else
692 dev_err(dev, "wrong COG ID 0x%02x\n", ret);
693 power_off(epd);
694 goto out_exit;
695 }
696
697 /* Disable OE */
698 repaper_write_val(spi, 0x02, 0x40);
699
700 ret = repaper_read_val(spi, 0x0f);
701 if (ret < 0 || !(ret & 0x80)) {
702 if (ret < 0)
703 DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
704 else
705 DRM_DEV_ERROR(dev, "panel is reported broken\n");
706 power_off(epd);
707 goto out_exit;
708 }
709
710 /* Power saving mode */
711 repaper_write_val(spi, 0x0b, 0x02);
712 /* Channel select */
713 repaper_write_buf(spi, 0x01, epd->channel_select, 8);
714 /* High power mode osc */
715 repaper_write_val(spi, 0x07, 0xd1);
716 /* Power setting */
717 repaper_write_val(spi, 0x08, 0x02);
718 /* Vcom level */
719 repaper_write_val(spi, 0x09, 0xc2);
720 /* Power setting */
721 repaper_write_val(spi, 0x04, 0x03);
722 /* Driver latch on */
723 repaper_write_val(spi, 0x03, 0x01);
724 /* Driver latch off */
725 repaper_write_val(spi, 0x03, 0x00);
726 usleep_range(5000, 10000);
727
728 /* Start chargepump */
729 for (i = 0; i < 4; ++i) {
730 /* Charge pump positive voltage on - VGH/VDL on */
731 repaper_write_val(spi, 0x05, 0x01);
732 msleep(240);
733
734 /* Charge pump negative voltage on - VGL/VDL on */
735 repaper_write_val(spi, 0x05, 0x03);
736 msleep(40);
737
738 /* Charge pump Vcom on - Vcom driver on */
739 repaper_write_val(spi, 0x05, 0x0f);
740 msleep(40);
741
742 /* check DC/DC */
743 ret = repaper_read_val(spi, 0x0f);
744 if (ret < 0) {
745 DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
746 power_off(epd);
747 goto out_exit;
748 }
749
750 if (ret & 0x40) {
751 dc_ok = true;
752 break;
753 }
754 }
755
756 if (!dc_ok) {
757 DRM_DEV_ERROR(dev, "dc/dc failed\n");
758 power_off(epd);
759 goto out_exit;
760 }
761
762 /*
763 * Output enable to disable
764 * The userspace driver sets this to 0x04, but the datasheet says 0x06
765 */
766 repaper_write_val(spi, 0x02, 0x04);
767
768 epd->partial = false;
769 out_exit:
770 drm_dev_exit(idx);
771 }
772
repaper_pipe_disable(struct drm_simple_display_pipe * pipe)773 static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
774 {
775 struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
776 struct spi_device *spi = epd->spi;
777 unsigned int line;
778
779 /*
780 * This callback is not protected by drm_dev_enter/exit since we want to
781 * turn off the display on regular driver unload. It's highly unlikely
782 * that the underlying SPI controller is gone should this be called after
783 * unplug.
784 */
785
786 DRM_DEBUG_DRIVER("\n");
787
788 /* Nothing frame */
789 for (line = 0; line < epd->height; line++)
790 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
791 REPAPER_COMPENSATE);
792
793 /* 2.7" */
794 if (epd->border) {
795 /* Dummy line */
796 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
797 REPAPER_COMPENSATE);
798 msleep(25);
799 gpiod_set_value_cansleep(epd->border, 0);
800 msleep(200);
801 gpiod_set_value_cansleep(epd->border, 1);
802 } else {
803 /* Border dummy line */
804 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
805 REPAPER_NORMAL);
806 msleep(200);
807 }
808
809 /* not described in datasheet */
810 repaper_write_val(spi, 0x0b, 0x00);
811 /* Latch reset turn on */
812 repaper_write_val(spi, 0x03, 0x01);
813 /* Power off charge pump Vcom */
814 repaper_write_val(spi, 0x05, 0x03);
815 /* Power off charge pump neg voltage */
816 repaper_write_val(spi, 0x05, 0x01);
817 msleep(120);
818 /* Discharge internal */
819 repaper_write_val(spi, 0x04, 0x80);
820 /* turn off all charge pumps */
821 repaper_write_val(spi, 0x05, 0x00);
822 /* Turn off osc */
823 repaper_write_val(spi, 0x07, 0x01);
824 msleep(50);
825
826 power_off(epd);
827 }
828
repaper_pipe_update(struct drm_simple_display_pipe * pipe,struct drm_plane_state * old_state)829 static void repaper_pipe_update(struct drm_simple_display_pipe *pipe,
830 struct drm_plane_state *old_state)
831 {
832 struct drm_plane_state *state = pipe->plane.state;
833 struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
834 struct drm_rect rect;
835
836 if (!pipe->crtc.state->active)
837 return;
838
839 if (drm_atomic_helper_damage_merged(old_state, state, &rect))
840 repaper_fb_dirty(state->fb, shadow_plane_state->data,
841 &shadow_plane_state->fmtcnv_state);
842 }
843
844 static const struct drm_simple_display_pipe_funcs repaper_pipe_funcs = {
845 .mode_valid = repaper_pipe_mode_valid,
846 .enable = repaper_pipe_enable,
847 .disable = repaper_pipe_disable,
848 .update = repaper_pipe_update,
849 DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS,
850 };
851
repaper_connector_get_modes(struct drm_connector * connector)852 static int repaper_connector_get_modes(struct drm_connector *connector)
853 {
854 struct repaper_epd *epd = drm_to_epd(connector->dev);
855
856 return drm_connector_helper_get_modes_fixed(connector, epd->mode);
857 }
858
859 static const struct drm_connector_helper_funcs repaper_connector_hfuncs = {
860 .get_modes = repaper_connector_get_modes,
861 };
862
863 static const struct drm_connector_funcs repaper_connector_funcs = {
864 .reset = drm_atomic_helper_connector_reset,
865 .fill_modes = drm_helper_probe_single_connector_modes,
866 .destroy = drm_connector_cleanup,
867 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
868 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
869 };
870
871 static const struct drm_mode_config_funcs repaper_mode_config_funcs = {
872 .fb_create = drm_gem_fb_create_with_dirty,
873 .atomic_check = drm_atomic_helper_check,
874 .atomic_commit = drm_atomic_helper_commit,
875 };
876
877 static const uint32_t repaper_formats[] = {
878 DRM_FORMAT_XRGB8888,
879 };
880
881 static const struct drm_display_mode repaper_e1144cs021_mode = {
882 DRM_SIMPLE_MODE(128, 96, 29, 22),
883 };
884
885 static const u8 repaper_e1144cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
886 0x00, 0x0f, 0xff, 0x00 };
887
888 static const struct drm_display_mode repaper_e1190cs021_mode = {
889 DRM_SIMPLE_MODE(144, 128, 36, 32),
890 };
891
892 static const u8 repaper_e1190cs021_cs[] = { 0x00, 0x00, 0x00, 0x03,
893 0xfc, 0x00, 0x00, 0xff };
894
895 static const struct drm_display_mode repaper_e2200cs021_mode = {
896 DRM_SIMPLE_MODE(200, 96, 46, 22),
897 };
898
899 static const u8 repaper_e2200cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
900 0x01, 0xff, 0xe0, 0x00 };
901
902 static const struct drm_display_mode repaper_e2271cs021_mode = {
903 DRM_SIMPLE_MODE(264, 176, 57, 38),
904 };
905
906 static const u8 repaper_e2271cs021_cs[] = { 0x00, 0x00, 0x00, 0x7f,
907 0xff, 0xfe, 0x00, 0x00 };
908
909 DEFINE_DRM_GEM_DMA_FOPS(repaper_fops);
910
911 static const struct drm_driver repaper_driver = {
912 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
913 .fops = &repaper_fops,
914 DRM_GEM_DMA_DRIVER_OPS_VMAP,
915 DRM_FBDEV_DMA_DRIVER_OPS,
916 .name = "repaper",
917 .desc = "Pervasive Displays RePaper e-ink panels",
918 .major = 1,
919 .minor = 0,
920 };
921
922 static const struct of_device_id repaper_of_match[] = {
923 { .compatible = "pervasive,e1144cs021", .data = (void *)E1144CS021 },
924 { .compatible = "pervasive,e1190cs021", .data = (void *)E1190CS021 },
925 { .compatible = "pervasive,e2200cs021", .data = (void *)E2200CS021 },
926 { .compatible = "pervasive,e2271cs021", .data = (void *)E2271CS021 },
927 {},
928 };
929 MODULE_DEVICE_TABLE(of, repaper_of_match);
930
931 static const struct spi_device_id repaper_id[] = {
932 { "e1144cs021", E1144CS021 },
933 { "e1190cs021", E1190CS021 },
934 { "e2200cs021", E2200CS021 },
935 { "e2271cs021", E2271CS021 },
936 { },
937 };
938 MODULE_DEVICE_TABLE(spi, repaper_id);
939
repaper_probe(struct spi_device * spi)940 static int repaper_probe(struct spi_device *spi)
941 {
942 const struct drm_display_mode *mode;
943 const struct spi_device_id *spi_id;
944 struct device *dev = &spi->dev;
945 enum repaper_model model;
946 const char *thermal_zone;
947 struct repaper_epd *epd;
948 size_t line_buffer_size;
949 struct drm_device *drm;
950 const void *match;
951 int ret;
952
953 match = device_get_match_data(dev);
954 if (match) {
955 model = (enum repaper_model)(uintptr_t)match;
956 } else {
957 spi_id = spi_get_device_id(spi);
958 model = (enum repaper_model)spi_id->driver_data;
959 }
960
961 /* The SPI device is used to allocate dma memory */
962 if (!dev->coherent_dma_mask) {
963 ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
964 if (ret) {
965 dev_warn(dev, "Failed to set dma mask %d\n", ret);
966 return ret;
967 }
968 }
969
970 epd = devm_drm_dev_alloc(dev, &repaper_driver,
971 struct repaper_epd, drm);
972 if (IS_ERR(epd))
973 return PTR_ERR(epd);
974
975 drm = &epd->drm;
976
977 ret = drmm_mode_config_init(drm);
978 if (ret)
979 return ret;
980 drm->mode_config.funcs = &repaper_mode_config_funcs;
981
982 epd->spi = spi;
983
984 epd->panel_on = devm_gpiod_get(dev, "panel-on", GPIOD_OUT_LOW);
985 if (IS_ERR(epd->panel_on)) {
986 ret = PTR_ERR(epd->panel_on);
987 if (ret != -EPROBE_DEFER)
988 DRM_DEV_ERROR(dev, "Failed to get gpio 'panel-on'\n");
989 return ret;
990 }
991
992 epd->discharge = devm_gpiod_get(dev, "discharge", GPIOD_OUT_LOW);
993 if (IS_ERR(epd->discharge)) {
994 ret = PTR_ERR(epd->discharge);
995 if (ret != -EPROBE_DEFER)
996 DRM_DEV_ERROR(dev, "Failed to get gpio 'discharge'\n");
997 return ret;
998 }
999
1000 epd->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
1001 if (IS_ERR(epd->reset)) {
1002 ret = PTR_ERR(epd->reset);
1003 if (ret != -EPROBE_DEFER)
1004 DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
1005 return ret;
1006 }
1007
1008 epd->busy = devm_gpiod_get(dev, "busy", GPIOD_IN);
1009 if (IS_ERR(epd->busy)) {
1010 ret = PTR_ERR(epd->busy);
1011 if (ret != -EPROBE_DEFER)
1012 DRM_DEV_ERROR(dev, "Failed to get gpio 'busy'\n");
1013 return ret;
1014 }
1015
1016 if (!device_property_read_string(dev, "pervasive,thermal-zone",
1017 &thermal_zone)) {
1018 epd->thermal = thermal_zone_get_zone_by_name(thermal_zone);
1019 if (IS_ERR(epd->thermal)) {
1020 DRM_DEV_ERROR(dev, "Failed to get thermal zone: %s\n", thermal_zone);
1021 return PTR_ERR(epd->thermal);
1022 }
1023 }
1024
1025 switch (model) {
1026 case E1144CS021:
1027 mode = &repaper_e1144cs021_mode;
1028 epd->channel_select = repaper_e1144cs021_cs;
1029 epd->stage_time = 480;
1030 epd->bytes_per_scan = 96 / 4;
1031 epd->middle_scan = true; /* data-scan-data */
1032 epd->pre_border_byte = false;
1033 epd->border_byte = REPAPER_BORDER_BYTE_ZERO;
1034 break;
1035
1036 case E1190CS021:
1037 mode = &repaper_e1190cs021_mode;
1038 epd->channel_select = repaper_e1190cs021_cs;
1039 epd->stage_time = 480;
1040 epd->bytes_per_scan = 128 / 4 / 2;
1041 epd->middle_scan = false; /* scan-data-scan */
1042 epd->pre_border_byte = false;
1043 epd->border_byte = REPAPER_BORDER_BYTE_SET;
1044 break;
1045
1046 case E2200CS021:
1047 mode = &repaper_e2200cs021_mode;
1048 epd->channel_select = repaper_e2200cs021_cs;
1049 epd->stage_time = 480;
1050 epd->bytes_per_scan = 96 / 4;
1051 epd->middle_scan = true; /* data-scan-data */
1052 epd->pre_border_byte = true;
1053 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1054 break;
1055
1056 case E2271CS021:
1057 epd->border = devm_gpiod_get(dev, "border", GPIOD_OUT_LOW);
1058 if (IS_ERR(epd->border)) {
1059 ret = PTR_ERR(epd->border);
1060 if (ret != -EPROBE_DEFER)
1061 DRM_DEV_ERROR(dev, "Failed to get gpio 'border'\n");
1062 return ret;
1063 }
1064
1065 mode = &repaper_e2271cs021_mode;
1066 epd->channel_select = repaper_e2271cs021_cs;
1067 epd->stage_time = 630;
1068 epd->bytes_per_scan = 176 / 4;
1069 epd->middle_scan = true; /* data-scan-data */
1070 epd->pre_border_byte = true;
1071 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1072 break;
1073
1074 default:
1075 return -ENODEV;
1076 }
1077
1078 epd->mode = mode;
1079 epd->width = mode->hdisplay;
1080 epd->height = mode->vdisplay;
1081 epd->factored_stage_time = epd->stage_time;
1082
1083 line_buffer_size = 2 * epd->width / 8 + epd->bytes_per_scan + 2;
1084 epd->line_buffer = devm_kzalloc(dev, line_buffer_size, GFP_KERNEL);
1085 if (!epd->line_buffer)
1086 return -ENOMEM;
1087
1088 epd->current_frame = devm_kzalloc(dev, epd->width * epd->height / 8,
1089 GFP_KERNEL);
1090 if (!epd->current_frame)
1091 return -ENOMEM;
1092
1093 drm->mode_config.min_width = mode->hdisplay;
1094 drm->mode_config.max_width = mode->hdisplay;
1095 drm->mode_config.min_height = mode->vdisplay;
1096 drm->mode_config.max_height = mode->vdisplay;
1097
1098 drm_connector_helper_add(&epd->connector, &repaper_connector_hfuncs);
1099 ret = drm_connector_init(drm, &epd->connector, &repaper_connector_funcs,
1100 DRM_MODE_CONNECTOR_SPI);
1101 if (ret)
1102 return ret;
1103
1104 ret = drm_simple_display_pipe_init(drm, &epd->pipe, &repaper_pipe_funcs,
1105 repaper_formats, ARRAY_SIZE(repaper_formats),
1106 NULL, &epd->connector);
1107 if (ret)
1108 return ret;
1109
1110 drm_mode_config_reset(drm);
1111
1112 ret = drm_dev_register(drm, 0);
1113 if (ret)
1114 return ret;
1115
1116 spi_set_drvdata(spi, drm);
1117
1118 DRM_DEBUG_DRIVER("SPI speed: %uMHz\n", spi->max_speed_hz / 1000000);
1119
1120 drm_client_setup(drm, NULL);
1121
1122 return 0;
1123 }
1124
repaper_remove(struct spi_device * spi)1125 static void repaper_remove(struct spi_device *spi)
1126 {
1127 struct drm_device *drm = spi_get_drvdata(spi);
1128
1129 drm_dev_unplug(drm);
1130 drm_atomic_helper_shutdown(drm);
1131 }
1132
repaper_shutdown(struct spi_device * spi)1133 static void repaper_shutdown(struct spi_device *spi)
1134 {
1135 drm_atomic_helper_shutdown(spi_get_drvdata(spi));
1136 }
1137
1138 static struct spi_driver repaper_spi_driver = {
1139 .driver = {
1140 .name = "repaper",
1141 .of_match_table = repaper_of_match,
1142 },
1143 .id_table = repaper_id,
1144 .probe = repaper_probe,
1145 .remove = repaper_remove,
1146 .shutdown = repaper_shutdown,
1147 };
1148 module_spi_driver(repaper_spi_driver);
1149
1150 MODULE_DESCRIPTION("Pervasive Displays RePaper DRM driver");
1151 MODULE_AUTHOR("Noralf Trønnes");
1152 MODULE_LICENSE("GPL");
1153