cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

repaper.c (28698B)


      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
     42enum repaper_model {
     43	/* 0 is reserved to avoid clashing with NULL */
     44	E1144CS021 = 1,
     45	E1190CS021,
     46	E2200CS021,
     47	E2271CS021,
     48};
     49
     50enum 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
     57enum repaper_epd_border_byte {
     58	REPAPER_BORDER_BYTE_NONE,
     59	REPAPER_BORDER_BYTE_ZERO,
     60	REPAPER_BORDER_BYTE_SET,
     61};
     62
     63struct 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
     95static inline struct repaper_epd *drm_to_epd(struct drm_device *drm)
     96{
     97	return container_of(drm, struct repaper_epd, drm);
     98}
     99
    100static 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
    142out_free:
    143	kfree(headerbuf);
    144	kfree(txbuf);
    145	kfree(rxbuf);
    146
    147	return ret;
    148}
    149
    150static 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, &reg, NULL, 1);
    156	if (ret)
    157		return ret;
    158
    159	return repaper_spi_transfer(spi, 0x72, buf, NULL, len);
    160}
    161
    162static int repaper_write_val(struct spi_device *spi, u8 reg, u8 val)
    163{
    164	return repaper_write_buf(spi, reg, &val, 1);
    165}
    166
    167static 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, &reg, 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
    181static 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
    191static 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,... */
    199static 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,... */
    245static 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 */
    285static 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 */
    295static 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 */
    339static 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
    423static 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
    432static 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
    453static 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
    464static 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
    475static 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
    511static 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
    594out_free:
    595	kfree(buf);
    596out_exit:
    597	drm_dev_exit(idx);
    598
    599	return ret;
    600}
    601
    602static 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
    619static 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;
    755out_exit:
    756	drm_dev_exit(idx);
    757}
    758
    759static 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
    815static 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
    828static 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
    834static 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
    855static const struct drm_connector_helper_funcs repaper_connector_hfuncs = {
    856	.get_modes = repaper_connector_get_modes,
    857};
    858
    859static 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
    867static 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
    873static const uint32_t repaper_formats[] = {
    874	DRM_FORMAT_XRGB8888,
    875};
    876
    877static const struct drm_display_mode repaper_e1144cs021_mode = {
    878	DRM_SIMPLE_MODE(128, 96, 29, 22),
    879};
    880
    881static const u8 repaper_e1144cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
    882					    0x00, 0x0f, 0xff, 0x00 };
    883
    884static const struct drm_display_mode repaper_e1190cs021_mode = {
    885	DRM_SIMPLE_MODE(144, 128, 36, 32),
    886};
    887
    888static const u8 repaper_e1190cs021_cs[] = { 0x00, 0x00, 0x00, 0x03,
    889					    0xfc, 0x00, 0x00, 0xff };
    890
    891static const struct drm_display_mode repaper_e2200cs021_mode = {
    892	DRM_SIMPLE_MODE(200, 96, 46, 22),
    893};
    894
    895static const u8 repaper_e2200cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
    896					    0x01, 0xff, 0xe0, 0x00 };
    897
    898static const struct drm_display_mode repaper_e2271cs021_mode = {
    899	DRM_SIMPLE_MODE(264, 176, 57, 38),
    900};
    901
    902static const u8 repaper_e2271cs021_cs[] = { 0x00, 0x00, 0x00, 0x7f,
    903					    0xff, 0xfe, 0x00, 0x00 };
    904
    905DEFINE_DRM_GEM_CMA_FOPS(repaper_fops);
    906
    907static 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
    918static 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};
    925MODULE_DEVICE_TABLE(of, repaper_of_match);
    926
    927static const struct spi_device_id repaper_id[] = {
    928	{ "e1144cs021", E1144CS021 },
    929	{ "e1190cs021", E1190CS021 },
    930	{ "e2200cs021", E2200CS021 },
    931	{ "e2271cs021", E2271CS021 },
    932	{ },
    933};
    934MODULE_DEVICE_TABLE(spi, repaper_id);
    935
    936static 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
   1121static 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
   1129static void repaper_shutdown(struct spi_device *spi)
   1130{
   1131	drm_atomic_helper_shutdown(spi_get_drvdata(spi));
   1132}
   1133
   1134static 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};
   1144module_spi_driver(repaper_spi_driver);
   1145
   1146MODULE_DESCRIPTION("Pervasive Displays RePaper DRM driver");
   1147MODULE_AUTHOR("Noralf Trønnes");
   1148MODULE_LICENSE("GPL");