Commit eac99d4a authored by David Lechner's avatar David Lechner Committed by Noralf Trønnes
Browse files

drm/tinydrm: add support for LEGO MINDSTORMS EV3 LCD 



LEGO MINDSTORMS EV3 has an LCD with a ST7586 controller. This adds a new
module for the ST7586 controller with parameters for the LEGO MINDSTORMS
EV3 LCD display.

Signed-off-by: default avatarDavid Lechner <david@lechnology.com>
Reviewed-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Signed-off-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1502127581-10517-4-git-send-email-david@lechnology.com
parent aee02b0f

MAINTAINERS

+6 −0
Original line number Diff line number Diff line
@@ -4380,6 +4380,12 @@ S: Orphan / Obsolete 
F:	drivers/gpu/drm/sis/

F:	include/uapi/drm/sis_drm.h



DRM DRIVER FOR SITRONIX ST7586 PANELS

M:	David Lechner <david@lechnology.com>

S:	Maintained

F:	drivers/gpu/drm/tinydrm/st7586.c

F:	Documentation/devicetree/bindings/display/st7586.txt



DRM DRIVER FOR TDFX VIDEO CARDS

S:	Orphan / Obsolete

F:	drivers/gpu/drm/tdfx/

drivers/gpu/drm/tinydrm/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -32,3 +32,13 @@ config TINYDRM_REPAPER 
	  2.71" TFT EPD Panel (E2271CS021)



	  If M is selected the module will be called repaper.



config TINYDRM_ST7586

	tristate "DRM support for Sitronix ST7586 display panels"

	depends on DRM_TINYDRM && SPI

	select TINYDRM_MIPI_DBI

	help

	  DRM driver for the following Sitronix ST7586 panels:

	  * LEGO MINDSTORMS EV3



	  If M is selected the module will be called st7586.

drivers/gpu/drm/tinydrm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -6,3 +6,4 @@ obj-$(CONFIG_TINYDRM_MIPI_DBI) += mipi-dbi.o 
# Displays

obj-$(CONFIG_TINYDRM_MI0283QT)		+= mi0283qt.o

obj-$(CONFIG_TINYDRM_REPAPER)		+= repaper.o

obj-$(CONFIG_TINYDRM_ST7586)		+= st7586.o

drivers/gpu/drm/tinydrm/st7586.c

0 → 100644
+428 −0
Original line number Diff line number Diff line 
/*

 * DRM driver for Sitronix ST7586 panels

 *

 * Copyright 2017 David Lechner <david@lechnology.com>

 *

 * 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/dma-buf.h>

#include <linux/gpio/consumer.h>

#include <linux/module.h>

#include <linux/property.h>

#include <linux/spi/spi.h>

#include <video/mipi_display.h>



#include <drm/tinydrm/mipi-dbi.h>

#include <drm/tinydrm/tinydrm-helpers.h>



/* controller-specific commands */

#define ST7586_DISP_MODE_GRAY	0x38

#define ST7586_DISP_MODE_MONO	0x39

#define ST7586_ENABLE_DDRAM	0x3a

#define ST7586_SET_DISP_DUTY	0xb0

#define ST7586_SET_PART_DISP	0xb4

#define ST7586_SET_NLINE_INV	0xb5

#define ST7586_SET_VOP		0xc0

#define ST7586_SET_BIAS_SYSTEM	0xc3

#define ST7586_SET_BOOST_LEVEL	0xc4

#define ST7586_SET_VOP_OFFSET	0xc7

#define ST7586_ENABLE_ANALOG	0xd0

#define ST7586_AUTO_READ_CTRL	0xd7

#define ST7586_OTP_RW_CTRL	0xe0

#define ST7586_OTP_CTRL_OUT	0xe1

#define ST7586_OTP_READ		0xe3



#define ST7586_DISP_CTRL_MX	BIT(6)

#define ST7586_DISP_CTRL_MY	BIT(7)



/*

 * The ST7586 controller has an unusual pixel format where 2bpp grayscale is

 * packed 3 pixels per byte with the first two pixels using 3 bits and the 3rd

 * pixel using only 2 bits.

 *

 * |  D7  |  D6  |  D5  ||      |      || 2bpp |

 * | (D4) | (D3) | (D2) ||  D1  |  D0  || GRAY |

 * +------+------+------++------+------++------+

 * |  1   |  1   |  1   ||  1   |  1   || 0  0 | black

 * |  1   |  0   |  0   ||  1   |  0   || 0  1 | dark gray

 * |  0   |  1   |  0   ||  0   |  1   || 1  0 | light gray

 * |  0   |  0   |  0   ||  0   |  0   || 1  1 | white

 */



static const u8 st7586_lookup[] = { 0x7, 0x4, 0x2, 0x0 };



static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,

				       struct drm_framebuffer *fb,

				       struct drm_clip_rect *clip)

{

	size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);

	unsigned int x, y;

	u8 *src, *buf, val;



	buf = kmalloc(len, GFP_KERNEL);

	if (!buf)

		return;



	tinydrm_xrgb8888_to_gray8(buf, vaddr, fb, clip);

	src = buf;



	for (y = clip->y1; y < clip->y2; y++) {

		for (x = clip->x1; x < clip->x2; x += 3) {

			val = st7586_lookup[*src++ >> 6] << 5;

			val |= st7586_lookup[*src++ >> 6] << 2;

			val |= st7586_lookup[*src++ >> 6] >> 1;

			*dst++ = val;

		}

	}



	kfree(buf);

}



static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,

			   struct drm_clip_rect *clip)

{

	struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);

	struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;

	void *src = cma_obj->vaddr;

	int ret = 0;



	if (import_attach) {

		ret = dma_buf_begin_cpu_access(import_attach->dmabuf,

					       DMA_FROM_DEVICE);

		if (ret)

			return ret;

	}



	st7586_xrgb8888_to_gray332(dst, src, fb, clip);



	if (import_attach)

		ret = dma_buf_end_cpu_access(import_attach->dmabuf,

					     DMA_FROM_DEVICE);



	return ret;

}



static int st7586_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 mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);

	struct drm_clip_rect clip;

	int start, end;

	int ret = 0;



	mutex_lock(&tdev->dirty_lock);



	if (!mipi->enabled)

		goto out_unlock;



	/* fbdev can flush even when we're not interested */

	if (tdev->pipe.plane.fb != fb)

		goto out_unlock;



	tinydrm_merge_clips(&clip, clips, num_clips, flags, fb->width,

			    fb->height);



	/* 3 pixels per byte, so grow clip to nearest multiple of 3 */

	clip.x1 = rounddown(clip.x1, 3);

	clip.x2 = roundup(clip.x2, 3);



	DRM_DEBUG("Flushing [FB:%d] x1=%u, x2=%u, y1=%u, y2=%u\n", fb->base.id,

		  clip.x1, clip.x2, clip.y1, clip.y2);



	ret = st7586_buf_copy(mipi->tx_buf, fb, &clip);

	if (ret)

		goto out_unlock;



	/* Pixels are packed 3 per byte */

	start = clip.x1 / 3;

	end = clip.x2 / 3;



	mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS,

			 (start >> 8) & 0xFF, start & 0xFF,

			 (end >> 8) & 0xFF, (end - 1) & 0xFF);

	mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS,

			 (clip.y1 >> 8) & 0xFF, clip.y1 & 0xFF,

			 (clip.y2 >> 8) & 0xFF, (clip.y2 - 1) & 0xFF);



	ret = mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START,

				   (u8 *)mipi->tx_buf,

				   (end - start) * (clip.y2 - clip.y1));



out_unlock:

	mutex_unlock(&tdev->dirty_lock);



	if (ret)

		dev_err_once(fb->dev->dev, "Failed to update display %d\n",

			     ret);



	return ret;

}



static const struct drm_framebuffer_funcs st7586_fb_funcs = {

	.destroy	= drm_fb_cma_destroy,

	.create_handle	= drm_fb_cma_create_handle,

	.dirty		= st7586_fb_dirty,

};



void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,

			struct drm_crtc_state *crtc_state)

{

	struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);

	struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);

	struct drm_framebuffer *fb = pipe->plane.fb;

	struct device *dev = tdev->drm->dev;

	int ret;

	u8 addr_mode;



	DRM_DEBUG_KMS("\n");



	mipi_dbi_hw_reset(mipi);

	ret = mipi_dbi_command(mipi, ST7586_AUTO_READ_CTRL, 0x9f);

	if (ret) {

		dev_err(dev, "Error sending command %d\n", ret);

		return;

	}



	mipi_dbi_command(mipi, ST7586_OTP_RW_CTRL, 0x00);



	msleep(10);



	mipi_dbi_command(mipi, ST7586_OTP_READ);



	msleep(20);



	mipi_dbi_command(mipi, ST7586_OTP_CTRL_OUT);

	mipi_dbi_command(mipi, MIPI_DCS_EXIT_SLEEP_MODE);

	mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);



	msleep(50);



	mipi_dbi_command(mipi, ST7586_SET_VOP_OFFSET, 0x00);

	mipi_dbi_command(mipi, ST7586_SET_VOP, 0xe3, 0x00);

	mipi_dbi_command(mipi, ST7586_SET_BIAS_SYSTEM, 0x02);

	mipi_dbi_command(mipi, ST7586_SET_BOOST_LEVEL, 0x04);

	mipi_dbi_command(mipi, ST7586_ENABLE_ANALOG, 0x1d);

	mipi_dbi_command(mipi, ST7586_SET_NLINE_INV, 0x00);

	mipi_dbi_command(mipi, ST7586_DISP_MODE_GRAY);

	mipi_dbi_command(mipi, ST7586_ENABLE_DDRAM, 0x02);



	switch (mipi->rotation) {

	default:

		addr_mode = 0x00;

		break;

	case 90:

		addr_mode = ST7586_DISP_CTRL_MY;

		break;

	case 180:

		addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;

		break;

	case 270:

		addr_mode = ST7586_DISP_CTRL_MX;

		break;

	}

	mipi_dbi_command(mipi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);



	mipi_dbi_command(mipi, ST7586_SET_DISP_DUTY, 0x7f);

	mipi_dbi_command(mipi, ST7586_SET_PART_DISP, 0xa0);

	mipi_dbi_command(mipi, MIPI_DCS_SET_PARTIAL_AREA, 0x00, 0x00, 0x00, 0x77);

	mipi_dbi_command(mipi, MIPI_DCS_EXIT_INVERT_MODE);



	msleep(100);



	mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_ON);



	mipi->enabled = true;



	if (fb)

		fb->funcs->dirty(fb, NULL, 0, 0, NULL, 0);

}



static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)

{

	struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);

	struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);



	DRM_DEBUG_KMS("\n");



	if (!mipi->enabled)

		return;



	mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);

	mipi->enabled = false;

}



static const u32 st7586_formats[] = {

	DRM_FORMAT_XRGB8888,

};



static int st7586_init(struct device *dev, struct mipi_dbi *mipi,

		const struct drm_simple_display_pipe_funcs *pipe_funcs,

		struct drm_driver *driver, const struct drm_display_mode *mode,

		unsigned int rotation)

{

	size_t bufsize = (mode->vdisplay + 2) / 3 * mode->hdisplay;

	struct tinydrm_device *tdev = &mipi->tinydrm;

	int ret;



	mutex_init(&mipi->cmdlock);



	mipi->tx_buf = devm_kmalloc(dev, bufsize, GFP_KERNEL);

	if (!mipi->tx_buf)

		return -ENOMEM;



	ret = devm_tinydrm_init(dev, tdev, &st7586_fb_funcs, driver);

	if (ret)

		return ret;



	ret = tinydrm_display_pipe_init(tdev, pipe_funcs,

					DRM_MODE_CONNECTOR_VIRTUAL,

					st7586_formats,

					ARRAY_SIZE(st7586_formats),

					mode, rotation);

	if (ret)

		return ret;



	tdev->drm->mode_config.preferred_depth = 32;

	mipi->rotation = rotation;



	drm_mode_config_reset(tdev->drm);



	DRM_DEBUG_KMS("preferred_depth=%u, rotation = %u\n",

		      tdev->drm->mode_config.preferred_depth, rotation);



	return 0;

}



static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {

	.enable		= st7586_pipe_enable,

	.disable	= st7586_pipe_disable,

	.update		= tinydrm_display_pipe_update,

	.prepare_fb	= tinydrm_display_pipe_prepare_fb,

};



static const struct drm_display_mode st7586_mode = {

	TINYDRM_MODE(178, 128, 37, 27),

};



DEFINE_DRM_GEM_CMA_FOPS(st7586_fops);



static struct drm_driver st7586_driver = {

	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |

				  DRIVER_ATOMIC,

	.fops			= &st7586_fops,

	TINYDRM_GEM_DRIVER_OPS,

	.lastclose		= tinydrm_lastclose,

	.debugfs_init		= mipi_dbi_debugfs_init,

	.name			= "st7586",

	.desc			= "Sitronix ST7586",

	.date			= "20170801",

	.major			= 1,

	.minor			= 0,

};



static const struct of_device_id st7586_of_match[] = {

	{ .compatible = "lego,ev3-lcd" },

	{},

};

MODULE_DEVICE_TABLE(of, st7586_of_match);



static const struct spi_device_id st7586_id[] = {

	{ "ev3-lcd", 0 },

	{ },

};

MODULE_DEVICE_TABLE(spi, st7586_id);



static int st7586_probe(struct spi_device *spi)

{

	struct device *dev = &spi->dev;

	struct tinydrm_device *tdev;

	struct mipi_dbi *mipi;

	struct gpio_desc *a0;

	u32 rotation = 0;

	int ret;



	mipi = devm_kzalloc(dev, sizeof(*mipi), GFP_KERNEL);

	if (!mipi)

		return -ENOMEM;



	mipi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);

	if (IS_ERR(mipi->reset)) {

		dev_err(dev, "Failed to get gpio 'reset'\n");

		return PTR_ERR(mipi->reset);

	}



	a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);

	if (IS_ERR(a0)) {

		dev_err(dev, "Failed to get gpio 'a0'\n");

		return PTR_ERR(a0);

	}



	device_property_read_u32(dev, "rotation", &rotation);



	ret = mipi_dbi_spi_init(spi, mipi, a0);

	if (ret)

		return ret;



	/* Cannot read from this controller via SPI */

	mipi->read_commands = NULL;



	/*

	 * we are using 8-bit data, so we are not actually swapping anything,

	 * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the

	 * right thing and not use 16-bit transfers (which results in swapped

	 * bytes on little-endian systems and causes out of order data to be

	 * sent to the display).

	 */

	mipi->swap_bytes = true;



	ret = st7586_init(&spi->dev, mipi, &st7586_pipe_funcs, &st7586_driver,

			  &st7586_mode, rotation);

	if (ret)

		return ret;



	tdev = &mipi->tinydrm;



	ret = devm_tinydrm_register(tdev);

	if (ret)

		return ret;



	spi_set_drvdata(spi, mipi);



	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 st7586_shutdown(struct spi_device *spi)

{

	struct mipi_dbi *mipi = spi_get_drvdata(spi);



	tinydrm_shutdown(&mipi->tinydrm);

}



static struct spi_driver st7586_spi_driver = {

	.driver = {

		.name = "st7586",

		.owner = THIS_MODULE,

		.of_match_table = st7586_of_match,

	},

	.id_table = st7586_id,

	.probe = st7586_probe,

	.shutdown = st7586_shutdown,

};

module_spi_driver(st7586_spi_driver);



MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");

MODULE_AUTHOR("David Lechner <david@lechnology.com>");

MODULE_LICENSE("GPL");

CRA Git | Maintained and supported by SUSTech CRA and CCSE