[PATCH v2 4/4] drm/tinydrm: Add RePaper e-ink driver

Daniel Vetter daniel at ffwll.ch
Mon Jun 26 09:49:53 UTC 2017


On Thu, Jun 08, 2017 at 05:14:35PM +0200, Noralf Trønnes wrote:
> This adds support for the Pervasive Displays RePaper branded displays.
> The controller code is taken from the userspace driver available
> through repaper.org. Only the V231 film is supported since the others
> are EOL.
> 
> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>

I took a look, and besides the tinydrm issues we've capture already this
all looks reasonable.

Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>

Yes I'm trying once more to sign you up for drm-misc commit rights, hence
not pushing ...
-Daniel
> ---
>  MAINTAINERS                       |    6 +
>  drivers/gpu/drm/tinydrm/Kconfig   |   12 +
>  drivers/gpu/drm/tinydrm/Makefile  |    1 +
>  drivers/gpu/drm/tinydrm/repaper.c | 1095 +++++++++++++++++++++++++++++++++++++
>  4 files changed, 1114 insertions(+)
>  create mode 100644 drivers/gpu/drm/tinydrm/repaper.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 757d487..800afa2 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4446,6 +4446,12 @@ M:	Dave Airlie <airlied at redhat.com>
>  S:	Odd Fixes
>  F:	drivers/gpu/drm/mgag200/
>  
> +DRM DRIVER FOR PERVASIVE DISPLAYS REPAPER PANELS
> +M:	Noralf Trønnes <noralf at tronnes.org>
> +S:	Maintained
> +F:	drivers/gpu/drm/tinydrm/repaper.c
> +F:	Documentation/devicetree/bindings/display/repaper.txt
> +
>  DRM DRIVER FOR RAGE 128 VIDEO CARDS
>  S:	Orphan / Obsolete
>  F:	drivers/gpu/drm/r128/
> diff --git a/drivers/gpu/drm/tinydrm/Kconfig b/drivers/gpu/drm/tinydrm/Kconfig
> index 3504c53..9596e44 100644
> --- a/drivers/gpu/drm/tinydrm/Kconfig
> +++ b/drivers/gpu/drm/tinydrm/Kconfig
> @@ -19,3 +19,15 @@ config TINYDRM_MI0283QT
>  	help
>  	  DRM driver for the Multi-Inno MI0283QT display panel
>  	  If M is selected the module will be called mi0283qt.
> +
> +config TINYDRM_REPAPER
> +	tristate "DRM support for Pervasive Displays RePaper panels (V231)"
> +	depends on DRM_TINYDRM && SPI
> +	help
> +	  DRM driver for the following Pervasive Displays panels:
> +	  1.44" TFT EPD Panel (E1144CS021)
> +	  1.90" TFT EPD Panel (E1190CS021)
> +	  2.00" TFT EPD Panel (E2200CS021)
> +	  2.71" TFT EPD Panel (E2271CS021)
> +
> +	  If M is selected the module will be called repaper.
> diff --git a/drivers/gpu/drm/tinydrm/Makefile b/drivers/gpu/drm/tinydrm/Makefile
> index 7a3604c..95bb4d4 100644
> --- a/drivers/gpu/drm/tinydrm/Makefile
> +++ b/drivers/gpu/drm/tinydrm/Makefile
> @@ -5,3 +5,4 @@ obj-$(CONFIG_TINYDRM_MIPI_DBI)		+= mipi-dbi.o
>  
>  # Displays
>  obj-$(CONFIG_TINYDRM_MI0283QT)		+= mi0283qt.o
> +obj-$(CONFIG_TINYDRM_REPAPER)		+= repaper.o
> diff --git a/drivers/gpu/drm/tinydrm/repaper.c b/drivers/gpu/drm/tinydrm/repaper.c
> new file mode 100644
> index 0000000..3343d3f
> --- /dev/null
> +++ b/drivers/gpu/drm/tinydrm/repaper.c
> @@ -0,0 +1,1095 @@
> +/*
> + * DRM driver for Pervasive Displays RePaper branded e-ink panels
> + *
> + * Copyright 2013-2017 Pervasive Displays, Inc.
> + * Copyright 2017 Noralf Trønnes
> + *
> + * The driver supports:
> + * Material Film: Aurora Mb (V231)
> + * Driver IC: G2 (eTC)
> + *
> + * The controller code was taken from the userspace driver:
> + * https://github.com/repaper/gratis
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/sched/clock.h>
> +#include <linux/spi/spi.h>
> +#include <linux/thermal.h>
> +
> +#include <drm/tinydrm/tinydrm.h>
> +#include <drm/tinydrm/tinydrm-helpers.h>
> +
> +#define REPAPER_RID_G2_COG_ID	0x12
> +
> +enum repaper_model {
> +	E1144CS021 = 1,
> +	E1190CS021,
> +	E2200CS021,
> +	E2271CS021,
> +};
> +
> +enum repaper_stage {         /* Image pixel -> Display pixel */
> +	REPAPER_COMPENSATE,  /* B -> W, W -> B (Current Image) */
> +	REPAPER_WHITE,       /* B -> N, W -> W (Current Image) */
> +	REPAPER_INVERSE,     /* B -> N, W -> B (New Image) */
> +	REPAPER_NORMAL       /* B -> B, W -> W (New Image) */
> +};
> +
> +enum repaper_epd_border_byte {
> +	REPAPER_BORDER_BYTE_NONE,
> +	REPAPER_BORDER_BYTE_ZERO,
> +	REPAPER_BORDER_BYTE_SET,
> +};
> +
> +struct repaper_epd {
> +	struct tinydrm_device tinydrm;
> +	struct spi_device *spi;
> +
> +	struct gpio_desc *panel_on;
> +	struct gpio_desc *border;
> +	struct gpio_desc *discharge;
> +	struct gpio_desc *reset;
> +	struct gpio_desc *busy;
> +
> +	struct thermal_zone_device *thermal;
> +
> +	unsigned int height;
> +	unsigned int width;
> +	unsigned int bytes_per_scan;
> +	const u8 *channel_select;
> +	unsigned int stage_time;
> +	unsigned int factored_stage_time;
> +	bool middle_scan;
> +	bool pre_border_byte;
> +	enum repaper_epd_border_byte border_byte;
> +
> +	u8 *line_buffer;
> +	void *current_frame;
> +
> +	bool enabled;
> +	bool cleared;
> +	bool partial;
> +};
> +
> +static inline struct repaper_epd *
> +epd_from_tinydrm(struct tinydrm_device *tdev)
> +{
> +	return container_of(tdev, struct repaper_epd, tinydrm);
> +}
> +
> +static int repaper_spi_transfer(struct spi_device *spi, u8 header,
> +				const void *tx, void *rx, size_t len)
> +{
> +	void *txbuf = NULL, *rxbuf = NULL;
> +	struct spi_transfer tr[2] = {};
> +	u8 *headerbuf;
> +	int ret;
> +
> +	headerbuf = kmalloc(1, GFP_KERNEL);
> +	if (!headerbuf)
> +		return -ENOMEM;
> +
> +	headerbuf[0] = header;
> +	tr[0].tx_buf = headerbuf;
> +	tr[0].len = 1;
> +
> +	/* Stack allocated tx? */
> +	if (tx && len <= 32) {
> +		txbuf = kmalloc(len, GFP_KERNEL);
> +		if (!txbuf) {
> +			ret = -ENOMEM;
> +			goto out_free;
> +		}
> +		memcpy(txbuf, tx, len);
> +	}
> +
> +	if (rx) {
> +		rxbuf = kmalloc(len, GFP_KERNEL);
> +		if (!rxbuf) {
> +			ret = -ENOMEM;
> +			goto out_free;
> +		}
> +	}
> +
> +	tr[1].tx_buf = txbuf ? txbuf : tx;
> +	tr[1].rx_buf = rxbuf;
> +	tr[1].len = len;
> +
> +	ndelay(80);
> +	ret = spi_sync_transfer(spi, tr, 2);
> +	if (rx && !ret)
> +		memcpy(rx, rxbuf, len);
> +
> +out_free:
> +	kfree(headerbuf);
> +	kfree(txbuf);
> +	kfree(rxbuf);
> +
> +	return ret;
> +}
> +
> +static int repaper_write_buf(struct spi_device *spi, u8 reg,
> +			     const u8 *buf, size_t len)
> +{
> +	int ret;
> +
> +	ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
> +	if (ret)
> +		return ret;
> +
> +	return repaper_spi_transfer(spi, 0x72, buf, NULL, len);
> +}
> +
> +static int repaper_write_val(struct spi_device *spi, u8 reg, u8 val)
> +{
> +	return repaper_write_buf(spi, reg, &val, 1);
> +}
> +
> +static int repaper_read_val(struct spi_device *spi, u8 reg)
> +{
> +	int ret;
> +	u8 val;
> +
> +	ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
> +	if (ret)
> +		return ret;
> +
> +	ret = repaper_spi_transfer(spi, 0x73, NULL, &val, 1);
> +
> +	return ret ? ret : val;
> +}
> +
> +static int repaper_read_id(struct spi_device *spi)
> +{
> +	int ret;
> +	u8 id;
> +
> +	ret = repaper_spi_transfer(spi, 0x71, NULL, &id, 1);
> +
> +	return ret ? ret : id;
> +}
> +
> +static void repaper_spi_mosi_low(struct spi_device *spi)
> +{
> +	const u8 buf[1] = { 0 };
> +
> +	spi_write(spi, buf, 1);
> +}
> +
> +/* pixels on display are numbered from 1 so even is actually bits 1,3,5,... */
> +static void repaper_even_pixels(struct repaper_epd *epd, u8 **pp,
> +				const u8 *data, u8 fixed_value, const u8 *mask,
> +				enum repaper_stage stage)
> +{
> +	unsigned int b;
> +
> +	for (b = 0; b < (epd->width / 8); b++) {
> +		if (data) {
> +			u8 pixels = data[b] & 0xaa;
> +			u8 pixel_mask = 0xff;
> +			u8 p1, p2, p3, p4;
> +
> +			if (mask) {
> +				pixel_mask = (mask[b] ^ pixels) & 0xaa;
> +				pixel_mask |= pixel_mask >> 1;
> +			}
> +
> +			switch (stage) {
> +			case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
> +				pixels = 0xaa | ((pixels ^ 0xaa) >> 1);
> +				break;
> +			case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
> +				pixels = 0x55 + ((pixels ^ 0xaa) >> 1);
> +				break;
> +			case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
> +				pixels = 0x55 | (pixels ^ 0xaa);
> +				break;
> +			case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
> +				pixels = 0xaa | (pixels >> 1);
> +				break;
> +			}
> +
> +			pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
> +			p1 = (pixels >> 6) & 0x03;
> +			p2 = (pixels >> 4) & 0x03;
> +			p3 = (pixels >> 2) & 0x03;
> +			p4 = (pixels >> 0) & 0x03;
> +			pixels = (p1 << 0) | (p2 << 2) | (p3 << 4) | (p4 << 6);
> +			*(*pp)++ = pixels;
> +		} else {
> +			*(*pp)++ = fixed_value;
> +		}
> +	}
> +}
> +
> +/* pixels on display are numbered from 1 so odd is actually bits 0,2,4,... */
> +static void repaper_odd_pixels(struct repaper_epd *epd, u8 **pp,
> +			       const u8 *data, u8 fixed_value, const u8 *mask,
> +			       enum repaper_stage stage)
> +{
> +	unsigned int b;
> +
> +	for (b = epd->width / 8; b > 0; b--) {
> +		if (data) {
> +			u8 pixels = data[b - 1] & 0x55;
> +			u8 pixel_mask = 0xff;
> +
> +			if (mask) {
> +				pixel_mask = (mask[b - 1] ^ pixels) & 0x55;
> +				pixel_mask |= pixel_mask << 1;
> +			}
> +
> +			switch (stage) {
> +			case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
> +				pixels = 0xaa | (pixels ^ 0x55);
> +				break;
> +			case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
> +				pixels = 0x55 + (pixels ^ 0x55);
> +				break;
> +			case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
> +				pixels = 0x55 | ((pixels ^ 0x55) << 1);
> +				break;
> +			case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
> +				pixels = 0xaa | pixels;
> +				break;
> +			}
> +
> +			pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
> +			*(*pp)++ = pixels;
> +		} else {
> +			*(*pp)++ = fixed_value;
> +		}
> +	}
> +}
> +
> +/* interleave bits: (byte)76543210 -> (16 bit).7.6.5.4.3.2.1 */
> +static inline u16 repaper_interleave_bits(u16 value)
> +{
> +	value = (value | (value << 4)) & 0x0f0f;
> +	value = (value | (value << 2)) & 0x3333;
> +	value = (value | (value << 1)) & 0x5555;
> +
> +	return value;
> +}
> +
> +/* pixels on display are numbered from 1 */
> +static void repaper_all_pixels(struct repaper_epd *epd, u8 **pp,
> +			       const u8 *data, u8 fixed_value, const u8 *mask,
> +			       enum repaper_stage stage)
> +{
> +	unsigned int b;
> +
> +	for (b = epd->width / 8; b > 0; b--) {
> +		if (data) {
> +			u16 pixels = repaper_interleave_bits(data[b - 1]);
> +			u16 pixel_mask = 0xffff;
> +
> +			if (mask) {
> +				pixel_mask = repaper_interleave_bits(mask[b - 1]);
> +
> +				pixel_mask = (pixel_mask ^ pixels) & 0x5555;
> +				pixel_mask |= pixel_mask << 1;
> +			}
> +
> +			switch (stage) {
> +			case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
> +				pixels = 0xaaaa | (pixels ^ 0x5555);
> +				break;
> +			case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
> +				pixels = 0x5555 + (pixels ^ 0x5555);
> +				break;
> +			case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
> +				pixels = 0x5555 | ((pixels ^ 0x5555) << 1);
> +				break;
> +			case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
> +				pixels = 0xaaaa | pixels;
> +				break;
> +			}
> +
> +			pixels = (pixels & pixel_mask) | (~pixel_mask & 0x5555);
> +			*(*pp)++ = pixels >> 8;
> +			*(*pp)++ = pixels;
> +		} else {
> +			*(*pp)++ = fixed_value;
> +			*(*pp)++ = fixed_value;
> +		}
> +	}
> +}
> +
> +/* output one line of scan and data bytes to the display */
> +static void repaper_one_line(struct repaper_epd *epd, unsigned int line,
> +			     const u8 *data, u8 fixed_value, const u8 *mask,
> +			     enum repaper_stage stage)
> +{
> +	u8 *p = epd->line_buffer;
> +	unsigned int b;
> +
> +	repaper_spi_mosi_low(epd->spi);
> +
> +	if (epd->pre_border_byte)
> +		*p++ = 0x00;
> +
> +	if (epd->middle_scan) {
> +		/* data bytes */
> +		repaper_odd_pixels(epd, &p, data, fixed_value, mask, stage);
> +
> +		/* scan line */
> +		for (b = epd->bytes_per_scan; b > 0; b--) {
> +			if (line / 4 == b - 1)
> +				*p++ = 0x03 << (2 * (line & 0x03));
> +			else
> +				*p++ = 0x00;
> +		}
> +
> +		/* data bytes */
> +		repaper_even_pixels(epd, &p, data, fixed_value, mask, stage);
> +	} else {
> +		/*
> +		 * even scan line, but as lines on display are numbered from 1,
> +		 * line: 1,3,5,...
> +		 */
> +		for (b = 0; b < epd->bytes_per_scan; b++) {
> +			if (0 != (line & 0x01) && line / 8 == b)
> +				*p++ = 0xc0 >> (line & 0x06);
> +			else
> +				*p++ = 0x00;
> +		}
> +
> +		/* data bytes */
> +		repaper_all_pixels(epd, &p, data, fixed_value, mask, stage);
> +
> +		/*
> +		 * odd scan line, but as lines on display are numbered from 1,
> +		 * line: 0,2,4,6,...
> +		 */
> +		for (b = epd->bytes_per_scan; b > 0; b--) {
> +			if (0 == (line & 0x01) && line / 8 == b - 1)
> +				*p++ = 0x03 << (line & 0x06);
> +			else
> +				*p++ = 0x00;
> +		}
> +	}
> +
> +	switch (epd->border_byte) {
> +	case REPAPER_BORDER_BYTE_NONE:
> +		break;
> +
> +	case REPAPER_BORDER_BYTE_ZERO:
> +		*p++ = 0x00;
> +		break;
> +
> +	case REPAPER_BORDER_BYTE_SET:
> +		switch (stage) {
> +		case REPAPER_COMPENSATE:
> +		case REPAPER_WHITE:
> +		case REPAPER_INVERSE:
> +			*p++ = 0x00;
> +			break;
> +		case REPAPER_NORMAL:
> +			*p++ = 0xaa;
> +			break;
> +		}
> +		break;
> +	}
> +
> +	repaper_write_buf(epd->spi, 0x0a, epd->line_buffer,
> +			  p - epd->line_buffer);
> +
> +	/* Output data to panel */
> +	repaper_write_val(epd->spi, 0x02, 0x07);
> +
> +	repaper_spi_mosi_low(epd->spi);
> +}
> +
> +static void repaper_frame_fixed(struct repaper_epd *epd, u8 fixed_value,
> +				enum repaper_stage stage)
> +{
> +	unsigned int line;
> +
> +	for (line = 0; line < epd->height; line++)
> +		repaper_one_line(epd, line, NULL, fixed_value, NULL, stage);
> +}
> +
> +static void repaper_frame_data(struct repaper_epd *epd, const u8 *image,
> +			       const u8 *mask, enum repaper_stage stage)
> +{
> +	unsigned int line;
> +
> +	if (!mask) {
> +		for (line = 0; line < epd->height; line++) {
> +			repaper_one_line(epd, line,
> +					 &image[line * (epd->width / 8)],
> +					 0, NULL, stage);
> +		}
> +	} else {
> +		for (line = 0; line < epd->height; line++) {
> +			size_t n = line * epd->width / 8;
> +
> +			repaper_one_line(epd, line, &image[n], 0, &mask[n],
> +					 stage);
> +		}
> +	}
> +}
> +
> +static void repaper_frame_fixed_repeat(struct repaper_epd *epd, u8 fixed_value,
> +				       enum repaper_stage stage)
> +{
> +	u64 start = local_clock();
> +	u64 end = start + (epd->factored_stage_time * 1000 * 1000);
> +
> +	do {
> +		repaper_frame_fixed(epd, fixed_value, stage);
> +	} while (local_clock() < end);
> +}
> +
> +static void repaper_frame_data_repeat(struct repaper_epd *epd, const u8 *image,
> +				      const u8 *mask, enum repaper_stage stage)
> +{
> +	u64 start = local_clock();
> +	u64 end = start + (epd->factored_stage_time * 1000 * 1000);
> +
> +	do {
> +		repaper_frame_data(epd, image, mask, stage);
> +	} while (local_clock() < end);
> +}
> +
> +static void repaper_get_temperature(struct repaper_epd *epd)
> +{
> +	int ret, temperature = 0;
> +	unsigned int factor10x;
> +
> +	if (!epd->thermal)
> +		return;
> +
> +	ret = thermal_zone_get_temp(epd->thermal, &temperature);
> +	if (ret) {
> +		dev_err(&epd->spi->dev, "Failed to get temperature (%d)\n",
> +			ret);
> +		return;
> +	}
> +
> +	temperature /= 1000;
> +
> +	if (temperature <= -10)
> +		factor10x = 170;
> +	else if (temperature <= -5)
> +		factor10x = 120;
> +	else if (temperature <= 5)
> +		factor10x = 80;
> +	else if (temperature <= 10)
> +		factor10x = 40;
> +	else if (temperature <= 15)
> +		factor10x = 30;
> +	else if (temperature <= 20)
> +		factor10x = 20;
> +	else if (temperature <= 40)
> +		factor10x = 10;
> +	else
> +		factor10x = 7;
> +
> +	epd->factored_stage_time = epd->stage_time * factor10x / 10;
> +}
> +
> +static void repaper_gray8_to_mono_reversed(u8 *buf, u32 width, u32 height)
> +{
> +	u8 *gray8 = buf, *mono = buf;
> +	int y, xb, i;
> +
> +	for (y = 0; y < height; y++)
> +		for (xb = 0; xb < width / 8; xb++) {
> +			u8 byte = 0x00;
> +
> +			for (i = 0; i < 8; i++) {
> +				int x = xb * 8 + i;
> +
> +				byte >>= 1;
> +				if (gray8[y * width + x] >> 7)
> +					byte |= BIT(7);
> +			}
> +			*mono++ = byte;
> +		}
> +}
> +
> +static int repaper_fb_dirty(struct drm_framebuffer *fb,
> +			    struct drm_file *file_priv,
> +			    unsigned int flags, unsigned int color,
> +			    struct drm_clip_rect *clips,
> +			    unsigned int num_clips)
> +{
> +	struct tinydrm_device *tdev = fb->dev->dev_private;
> +	struct repaper_epd *epd = epd_from_tinydrm(tdev);
> +	u8 *buf = NULL;
> +	int ret = 0;
> +
> +	mutex_lock(&tdev->dirty_lock);
> +
> +	if (!epd->enabled)
> +		goto out_unlock;
> +
> +	/* fbdev can flush even when we're not interested */
> +	if (tdev->pipe.plane.fb != fb)
> +		goto out_unlock;
> +
> +	repaper_get_temperature(epd);
> +
> +	DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
> +		  epd->factored_stage_time);
> +
> +	buf = kmalloc(fb->width * fb->height, GFP_KERNEL);
> +	if (!buf) {
> +		ret = -ENOMEM;
> +		goto out_unlock;
> +	}
> +
> +	ret = tinydrm_xrgb8888_to_gray8(buf, fb);
> +	if (ret)
> +		goto out_unlock;
> +
> +	repaper_gray8_to_mono_reversed(buf, fb->width, fb->height);
> +
> +	if (epd->partial) {
> +		repaper_frame_data_repeat(epd, buf, epd->current_frame,
> +					  REPAPER_NORMAL);
> +	} else if (epd->cleared) {
> +		repaper_frame_data_repeat(epd, epd->current_frame, NULL,
> +					  REPAPER_COMPENSATE);
> +		repaper_frame_data_repeat(epd, epd->current_frame, NULL,
> +					  REPAPER_WHITE);
> +		repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
> +		repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
> +
> +		epd->partial = true;
> +	} else {
> +		/* Clear display (anything -> white) */
> +		repaper_frame_fixed_repeat(epd, 0xff, REPAPER_COMPENSATE);
> +		repaper_frame_fixed_repeat(epd, 0xff, REPAPER_WHITE);
> +		repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_INVERSE);
> +		repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_NORMAL);
> +
> +		/* Assuming a clear (white) screen output an image */
> +		repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_COMPENSATE);
> +		repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_WHITE);
> +		repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
> +		repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
> +
> +		epd->cleared = true;
> +		epd->partial = true;
> +	}
> +
> +	memcpy(epd->current_frame, buf, fb->width * fb->height / 8);
> +
> +	/*
> +	 * An extra frame write is needed if pixels are set in the bottom line,
> +	 * or else grey lines rises up from the pixels
> +	 */
> +	if (epd->pre_border_byte) {
> +		unsigned int x;
> +
> +		for (x = 0; x < (fb->width / 8); x++)
> +			if (buf[x + (fb->width * (fb->height - 1) / 8)]) {
> +				repaper_frame_data_repeat(epd, buf,
> +							  epd->current_frame,
> +							  REPAPER_NORMAL);
> +				break;
> +			}
> +	}
> +
> +out_unlock:
> +	mutex_unlock(&tdev->dirty_lock);
> +
> +	if (ret)
> +		dev_err(fb->dev->dev, "Failed to update display (%d)\n", ret);
> +	kfree(buf);
> +
> +	return ret;
> +}
> +
> +static const struct drm_framebuffer_funcs repaper_fb_funcs = {
> +	.destroy	= drm_fb_cma_destroy,
> +	.create_handle	= drm_fb_cma_create_handle,
> +	.dirty		= repaper_fb_dirty,
> +};
> +
> +static void power_off(struct repaper_epd *epd)
> +{
> +	/* Turn off power and all signals */
> +	gpiod_set_value_cansleep(epd->reset, 0);
> +	gpiod_set_value_cansleep(epd->panel_on, 0);
> +	if (epd->border)
> +		gpiod_set_value_cansleep(epd->border, 0);
> +
> +	/* Ensure SPI MOSI and CLOCK are Low before CS Low */
> +	repaper_spi_mosi_low(epd->spi);
> +
> +	/* Discharge pulse */
> +	gpiod_set_value_cansleep(epd->discharge, 1);
> +	msleep(150);
> +	gpiod_set_value_cansleep(epd->discharge, 0);
> +}
> +
> +static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
> +				struct drm_crtc_state *crtc_state)
> +{
> +	struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
> +	struct repaper_epd *epd = epd_from_tinydrm(tdev);
> +	struct spi_device *spi = epd->spi;
> +	struct device *dev = &spi->dev;
> +	bool dc_ok = false;
> +	int i, ret;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	/* Power up sequence */
> +	gpiod_set_value_cansleep(epd->reset, 0);
> +	gpiod_set_value_cansleep(epd->panel_on, 0);
> +	gpiod_set_value_cansleep(epd->discharge, 0);
> +	if (epd->border)
> +		gpiod_set_value_cansleep(epd->border, 0);
> +	repaper_spi_mosi_low(spi);
> +	usleep_range(5000, 10000);
> +
> +	gpiod_set_value_cansleep(epd->panel_on, 1);
> +	/*
> +	 * This delay comes from the repaper.org userspace driver, it's not
> +	 * mentioned in the datasheet.
> +	 */
> +	usleep_range(10000, 15000);
> +	gpiod_set_value_cansleep(epd->reset, 1);
> +	if (epd->border)
> +		gpiod_set_value_cansleep(epd->border, 1);
> +	usleep_range(5000, 10000);
> +	gpiod_set_value_cansleep(epd->reset, 0);
> +	usleep_range(5000, 10000);
> +	gpiod_set_value_cansleep(epd->reset, 1);
> +	usleep_range(5000, 10000);
> +
> +	/* Wait for COG to become ready */
> +	for (i = 100; i > 0; i--) {
> +		if (!gpiod_get_value_cansleep(epd->busy))
> +			break;
> +
> +		usleep_range(10, 100);
> +	}
> +
> +	if (!i) {
> +		dev_err(dev, "timeout waiting for panel to become ready.\n");
> +		power_off(epd);
> +		return;
> +	}
> +
> +	repaper_read_id(spi);
> +	ret = repaper_read_id(spi);
> +	if (ret != REPAPER_RID_G2_COG_ID) {
> +		if (ret < 0)
> +			dev_err(dev, "failed to read chip (%d)\n", ret);
> +		else
> +			dev_err(dev, "wrong COG ID 0x%02x\n", ret);
> +		power_off(epd);
> +		return;
> +	}
> +
> +	/* Disable OE */
> +	repaper_write_val(spi, 0x02, 0x40);
> +
> +	ret = repaper_read_val(spi, 0x0f);
> +	if (ret < 0 || !(ret & 0x80)) {
> +		if (ret < 0)
> +			dev_err(dev, "failed to read chip (%d)\n", ret);
> +		else
> +			dev_err(dev, "panel is reported broken\n");
> +		power_off(epd);
> +		return;
> +	}
> +
> +	/* Power saving mode */
> +	repaper_write_val(spi, 0x0b, 0x02);
> +	/* Channel select */
> +	repaper_write_buf(spi, 0x01, epd->channel_select, 8);
> +	/* High power mode osc */
> +	repaper_write_val(spi, 0x07, 0xd1);
> +	/* Power setting */
> +	repaper_write_val(spi, 0x08, 0x02);
> +	/* Vcom level */
> +	repaper_write_val(spi, 0x09, 0xc2);
> +	/* Power setting */
> +	repaper_write_val(spi, 0x04, 0x03);
> +	/* Driver latch on */
> +	repaper_write_val(spi, 0x03, 0x01);
> +	/* Driver latch off */
> +	repaper_write_val(spi, 0x03, 0x00);
> +	usleep_range(5000, 10000);
> +
> +	/* Start chargepump */
> +	for (i = 0; i < 4; ++i) {
> +		/* Charge pump positive voltage on - VGH/VDL on */
> +		repaper_write_val(spi, 0x05, 0x01);
> +		msleep(240);
> +
> +		/* Charge pump negative voltage on - VGL/VDL on */
> +		repaper_write_val(spi, 0x05, 0x03);
> +		msleep(40);
> +
> +		/* Charge pump Vcom on - Vcom driver on */
> +		repaper_write_val(spi, 0x05, 0x0f);
> +		msleep(40);
> +
> +		/* check DC/DC */
> +		ret = repaper_read_val(spi, 0x0f);
> +		if (ret < 0) {
> +			dev_err(dev, "failed to read chip (%d)\n", ret);
> +			power_off(epd);
> +			return;
> +		}
> +
> +		if (ret & 0x40) {
> +			dc_ok = true;
> +			break;
> +		}
> +	}
> +
> +	if (!dc_ok) {
> +		dev_err(dev, "dc/dc failed\n");
> +		power_off(epd);
> +		return;
> +	}
> +
> +	/*
> +	 * Output enable to disable
> +	 * The userspace driver sets this to 0x04, but the datasheet says 0x06
> +	 */
> +	repaper_write_val(spi, 0x02, 0x04);
> +
> +	epd->enabled = true;
> +	epd->partial = false;
> +}
> +
> +static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
> +{
> +	struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
> +	struct repaper_epd *epd = epd_from_tinydrm(tdev);
> +	struct spi_device *spi = epd->spi;
> +	unsigned int line;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	mutex_lock(&tdev->dirty_lock);
> +	epd->enabled = false;
> +	mutex_unlock(&tdev->dirty_lock);
> +
> +	/* Nothing frame */
> +	for (line = 0; line < epd->height; line++)
> +		repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
> +				 REPAPER_COMPENSATE);
> +
> +	/* 2.7" */
> +	if (epd->border) {
> +		/* Dummy line */
> +		repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
> +				 REPAPER_COMPENSATE);
> +		msleep(25);
> +		gpiod_set_value_cansleep(epd->border, 0);
> +		msleep(200);
> +		gpiod_set_value_cansleep(epd->border, 1);
> +	} else {
> +		/* Border dummy line */
> +		repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
> +				 REPAPER_NORMAL);
> +		msleep(200);
> +	}
> +
> +	/* not described in datasheet */
> +	repaper_write_val(spi, 0x0b, 0x00);
> +	/* Latch reset turn on */
> +	repaper_write_val(spi, 0x03, 0x01);
> +	/* Power off charge pump Vcom */
> +	repaper_write_val(spi, 0x05, 0x03);
> +	/* Power off charge pump neg voltage */
> +	repaper_write_val(spi, 0x05, 0x01);
> +	msleep(120);
> +	/* Discharge internal */
> +	repaper_write_val(spi, 0x04, 0x80);
> +	/* turn off all charge pumps */
> +	repaper_write_val(spi, 0x05, 0x00);
> +	/* Turn off osc */
> +	repaper_write_val(spi, 0x07, 0x01);
> +	msleep(50);
> +
> +	power_off(epd);
> +}
> +
> +static const struct drm_simple_display_pipe_funcs repaper_pipe_funcs = {
> +	.enable = repaper_pipe_enable,
> +	.disable = repaper_pipe_disable,
> +	.update = tinydrm_display_pipe_update,
> +	.prepare_fb = tinydrm_display_pipe_prepare_fb,
> +};
> +
> +static const uint32_t repaper_formats[] = {
> +	DRM_FORMAT_XRGB8888,
> +};
> +
> +static const struct drm_display_mode repaper_e1144cs021_mode = {
> +	TINYDRM_MODE(128, 96, 29, 22),
> +};
> +
> +static const u8 repaper_e1144cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
> +					    0x00, 0x0f, 0xff, 0x00 };
> +
> +static const struct drm_display_mode repaper_e1190cs021_mode = {
> +	TINYDRM_MODE(144, 128, 36, 32),
> +};
> +
> +static const u8 repaper_e1190cs021_cs[] = { 0x00, 0x00, 0x00, 0x03,
> +					    0xfc, 0x00, 0x00, 0xff };
> +
> +static const struct drm_display_mode repaper_e2200cs021_mode = {
> +	TINYDRM_MODE(200, 96, 46, 22),
> +};
> +
> +static const u8 repaper_e2200cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
> +					    0x01, 0xff, 0xe0, 0x00 };
> +
> +static const struct drm_display_mode repaper_e2271cs021_mode = {
> +	TINYDRM_MODE(264, 176, 57, 38),
> +};
> +
> +static const u8 repaper_e2271cs021_cs[] = { 0x00, 0x00, 0x00, 0x7f,
> +					    0xff, 0xfe, 0x00, 0x00 };
> +
> +DEFINE_DRM_GEM_CMA_FOPS(repaper_fops);
> +
> +static struct drm_driver repaper_driver = {
> +	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
> +				  DRIVER_ATOMIC,
> +	.fops			= &repaper_fops,
> +	TINYDRM_GEM_DRIVER_OPS,
> +	.name			= "repaper",
> +	.desc			= "Pervasive Displays RePaper e-ink panels",
> +	.date			= "20170405",
> +	.major			= 1,
> +	.minor			= 0,
> +};
> +
> +static const struct of_device_id repaper_of_match[] = {
> +	{ .compatible = "pervasive,e1144cs021", .data = (void *)E1144CS021 },
> +	{ .compatible = "pervasive,e1190cs021", .data = (void *)E1190CS021 },
> +	{ .compatible = "pervasive,e2200cs021", .data = (void *)E2200CS021 },
> +	{ .compatible = "pervasive,e2271cs021", .data = (void *)E2271CS021 },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, repaper_of_match);
> +
> +static const struct spi_device_id repaper_id[] = {
> +	{ "e1144cs021", E1144CS021 },
> +	{ "e1190cs021", E1190CS021 },
> +	{ "e2200cs021", E2200CS021 },
> +	{ "e2271cs021", E2271CS021 },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(spi, repaper_id);
> +
> +static int repaper_probe(struct spi_device *spi)
> +{
> +	const struct drm_display_mode *mode;
> +	const struct spi_device_id *spi_id;
> +	const struct of_device_id *match;
> +	struct device *dev = &spi->dev;
> +	struct tinydrm_device *tdev;
> +	enum repaper_model model;
> +	const char *thermal_zone;
> +	struct repaper_epd *epd;
> +	size_t line_buffer_size;
> +	int ret;
> +
> +	match = of_match_device(repaper_of_match, dev);
> +	if (match) {
> +		model = (enum repaper_model)match->data;
> +	} else {
> +		spi_id = spi_get_device_id(spi);
> +		model = spi_id->driver_data;
> +	}
> +
> +	/* The SPI device is used to allocate dma memory */
> +	if (!dev->coherent_dma_mask) {
> +		ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
> +		if (ret) {
> +			dev_warn(dev, "Failed to set dma mask %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	epd = devm_kzalloc(dev, sizeof(*epd), GFP_KERNEL);
> +	if (!epd)
> +		return -ENOMEM;
> +
> +	epd->spi = spi;
> +
> +	epd->panel_on = devm_gpiod_get(dev, "panel-on", GPIOD_OUT_LOW);
> +	if (IS_ERR(epd->panel_on)) {
> +		ret = PTR_ERR(epd->panel_on);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get gpio 'panel-on'\n");
> +		return ret;
> +	}
> +
> +	epd->discharge = devm_gpiod_get(dev, "discharge", GPIOD_OUT_LOW);
> +	if (IS_ERR(epd->discharge)) {
> +		ret = PTR_ERR(epd->discharge);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get gpio 'discharge'\n");
> +		return ret;
> +	}
> +
> +	epd->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> +	if (IS_ERR(epd->reset)) {
> +		ret = PTR_ERR(epd->reset);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get gpio 'reset'\n");
> +		return ret;
> +	}
> +
> +	epd->busy = devm_gpiod_get(dev, "busy", GPIOD_IN);
> +	if (IS_ERR(epd->busy)) {
> +		ret = PTR_ERR(epd->busy);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get gpio 'busy'\n");
> +		return ret;
> +	}
> +
> +	if (!device_property_read_string(dev, "pervasive,thermal-zone",
> +					 &thermal_zone)) {
> +		epd->thermal = thermal_zone_get_zone_by_name(thermal_zone);
> +		if (IS_ERR(epd->thermal)) {
> +			dev_err(dev, "Failed to get thermal zone: %s\n",
> +				thermal_zone);
> +			return PTR_ERR(epd->thermal);
> +		}
> +	}
> +
> +	switch (model) {
> +	case E1144CS021:
> +		mode = &repaper_e1144cs021_mode;
> +		epd->channel_select = repaper_e1144cs021_cs;
> +		epd->stage_time = 480;
> +		epd->bytes_per_scan = 96 / 4;
> +		epd->middle_scan = true; /* data-scan-data */
> +		epd->pre_border_byte = false;
> +		epd->border_byte = REPAPER_BORDER_BYTE_ZERO;
> +		break;
> +
> +	case E1190CS021:
> +		mode = &repaper_e1190cs021_mode;
> +		epd->channel_select = repaper_e1190cs021_cs;
> +		epd->stage_time = 480;
> +		epd->bytes_per_scan = 128 / 4 / 2;
> +		epd->middle_scan = false; /* scan-data-scan */
> +		epd->pre_border_byte = false;
> +		epd->border_byte = REPAPER_BORDER_BYTE_SET;
> +		break;
> +
> +	case E2200CS021:
> +		mode = &repaper_e2200cs021_mode;
> +		epd->channel_select = repaper_e2200cs021_cs;
> +		epd->stage_time = 480;
> +		epd->bytes_per_scan = 96 / 4;
> +		epd->middle_scan = true; /* data-scan-data */
> +		epd->pre_border_byte = true;
> +		epd->border_byte = REPAPER_BORDER_BYTE_NONE;
> +		break;
> +
> +	case E2271CS021:
> +		epd->border = devm_gpiod_get(dev, "border", GPIOD_OUT_LOW);
> +		if (IS_ERR(epd->border)) {
> +			ret = PTR_ERR(epd->border);
> +			if (ret != -EPROBE_DEFER)
> +				dev_err(dev, "Failed to get gpio 'border'\n");
> +			return ret;
> +		}
> +
> +		mode = &repaper_e2271cs021_mode;
> +		epd->channel_select = repaper_e2271cs021_cs;
> +		epd->stage_time = 630;
> +		epd->bytes_per_scan = 176 / 4;
> +		epd->middle_scan = true; /* data-scan-data */
> +		epd->pre_border_byte = true;
> +		epd->border_byte = REPAPER_BORDER_BYTE_NONE;
> +		break;
> +
> +	default:
> +		return -ENODEV;
> +	}
> +
> +	epd->width = mode->hdisplay;
> +	epd->height = mode->vdisplay;
> +	epd->factored_stage_time = epd->stage_time;
> +
> +	line_buffer_size = 2 * epd->width / 8 + epd->bytes_per_scan + 2;
> +	epd->line_buffer = devm_kzalloc(dev, line_buffer_size, GFP_KERNEL);
> +	if (!epd->line_buffer)
> +		return -ENOMEM;
> +
> +	epd->current_frame = devm_kzalloc(dev, epd->width * epd->height / 8,
> +					  GFP_KERNEL);
> +	if (!epd->current_frame)
> +		return -ENOMEM;
> +
> +	tdev = &epd->tinydrm;
> +
> +	ret = devm_tinydrm_init(dev, tdev, &repaper_fb_funcs, &repaper_driver);
> +	if (ret)
> +		return ret;
> +
> +	ret = tinydrm_display_pipe_init(tdev, &repaper_pipe_funcs,
> +					DRM_MODE_CONNECTOR_VIRTUAL,
> +					repaper_formats,
> +					ARRAY_SIZE(repaper_formats), mode, 0);
> +	if (ret)
> +		return ret;
> +
> +	drm_mode_config_reset(tdev->drm);
> +
> +	ret = devm_tinydrm_register(tdev);
> +	if (ret)
> +		return ret;
> +
> +	spi_set_drvdata(spi, tdev);
> +
> +	DRM_DEBUG_DRIVER("Initialized %s:%s @%uMHz on minor %d\n",
> +			 tdev->drm->driver->name, dev_name(dev),
> +			 spi->max_speed_hz / 1000000,
> +			 tdev->drm->primary->index);
> +
> +	return 0;
> +}
> +
> +static void repaper_shutdown(struct spi_device *spi)
> +{
> +	struct tinydrm_device *tdev = spi_get_drvdata(spi);
> +
> +	tinydrm_shutdown(tdev);
> +}
> +
> +static struct spi_driver repaper_spi_driver = {
> +	.driver = {
> +		.name = "repaper",
> +		.owner = THIS_MODULE,
> +		.of_match_table = repaper_of_match,
> +	},
> +	.id_table = repaper_id,
> +	.probe = repaper_probe,
> +	.shutdown = repaper_shutdown,
> +};
> +module_spi_driver(repaper_spi_driver);
> +
> +MODULE_DESCRIPTION("Pervasive Displays RePaper DRM driver");
> +MODULE_AUTHOR("Noralf Trønnes");
> +MODULE_LICENSE("GPL");
> -- 
> 2.7.4
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


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