repaper.c

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