Message-ID: <32b134d1-84f3-8e3d-1d57-05c8b7c384bc@tronnes.org>
Date:   Wed, 2 Aug 2017 15:03:03 +0200
From:   Noralf Trønnes <noralf@...nnes.org>
To:     David Lechner <david@...hnology.com>,
        dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org
Cc:     Daniel Vetter <daniel@...ll.ch>, David Airlie <airlied@...ux.ie>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Sekhar Nori <nsekhar@...com>,
        Kevin Hilman <khilman@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/4] drm/tinydrm: add support for LEGO MINDSTORMS EV3
 LCD


Den 02.08.2017 00.11, skrev David Lechner:
> LEGO MINDSTORMS EV3 has an LCD with a ST7586 controller. This adds a new
> module for the ST7586 controller with parameters for the EV3 LCD display.
>
> Signed-off-by: David Lechner <david@...hnology.com>
> ---
>   .../devicetree/bindings/display/st7586.txt         |  26 +
>   drivers/gpu/drm/tinydrm/Kconfig                    |  10 +
>   drivers/gpu/drm/tinydrm/Makefile                   |   1 +
>   drivers/gpu/drm/tinydrm/st7586.c                   | 579 +++++++++++++++++++++
>   include/drm/tinydrm/st7586.h                       |  34 ++

Please add a MAINTAINERS entry.
That way you'll be notified on changes.

>   5 files changed, 650 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/display/st7586.txt
>   create mode 100644 drivers/gpu/drm/tinydrm/st7586.c
>   create mode 100644 include/drm/tinydrm/st7586.h
>
> diff --git a/Documentation/devicetree/bindings/display/st7586.txt b/Documentation/devicetree/bindings/display/st7586.txt
> new file mode 100644
> index 0000000..acf784aa
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/st7586.txt
> @@ -0,0 +1,26 @@
> +Sitronix ST7586 display panel
> +
> +Required properties:
> +- compatible:	"lego,ev3-lcd".
> +
> +The node for this driver must be a child node of a SPI controller, hence
> +all mandatory properties described in ../spi/spi-bus.txt must be specified.
> +
> +Optional properties:
> +- dc-gpios:	D/C pin. The presence/absence of this GPIO determines
> +		the panel interface mode (IM[3:0] pins):
> +		- present: IM=x110 4-wire 8-bit data serial interface
> +		- absent:  IM=x101 3-wire 9-bit data serial interface

This doesn't match the ST7586 datasheet I have, the pins are called
IF[3:1] and the values are different.

> +- reset-gpios:	Reset pin
> +- power-supply:	A regulator node for the supply voltage.
> +- backlight:	phandle of the backlight device attached to the panel
> +- rotation:	panel rotation in degrees counter clockwise (0,90,180,270)
> +
> +Example:
> +	display@0{
> +		compatible = "lego,ev3-lcd";
> +		reg = <0>;
> +		spi-max-frequency = <10000000>;
> +		dc-gpios = <&gpio 43 GPIO_ACTIVE_HIGH>;
> +		reset-gpios = <&gpio 80 GPIO_ACTIVE_HIGH>;
> +	};
> diff --git a/drivers/gpu/drm/tinydrm/Kconfig b/drivers/gpu/drm/tinydrm/Kconfig
> index f17c3ca..2e790e7 100644
> --- a/drivers/gpu/drm/tinydrm/Kconfig
> +++ b/drivers/gpu/drm/tinydrm/Kconfig
> @@ -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.
> diff --git a/drivers/gpu/drm/tinydrm/Makefile b/drivers/gpu/drm/tinydrm/Makefile
> index 95bb4d4..0c184bd 100644
> --- a/drivers/gpu/drm/tinydrm/Makefile
> +++ b/drivers/gpu/drm/tinydrm/Makefile
> @@ -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
> diff --git a/drivers/gpu/drm/tinydrm/st7586.c b/drivers/gpu/drm/tinydrm/st7586.c
> new file mode 100644
> index 0000000..6093021
> --- /dev/null
> +++ b/drivers/gpu/drm/tinydrm/st7586.c
> @@ -0,0 +1,579 @@
> +/*
> + * DRM driver for Sitronix ST7586 panels
> + *
> + * Copyright 2017 David Lechner <david@...hnology.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/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +#include <video/mipi_display.h>
> +
> +#include <drm/tinydrm/mipi-dbi.h>
> +#include <drm/tinydrm/st7586.h>
> +#include <drm/tinydrm/tinydrm-helpers.h>
> +
> +static inline u8 st7586_rgb565_to_gray2(u16 rgb)
> +{
> +	u8 r = (rgb & 0xf800) >> 11;
> +	u8 g = (rgb & 0x07e0) >> 5;
> +	u8 b = rgb & 0x001f;
> +	/* ITU BT.601: Y = 0.299 R + 0.587 G + 0.114 B */
> +	/* g is already * 2 because it is 6-bit */
> +	u8 gray5 = (3 * r + 3 * g + b) / 10;
> +
> +	return gray5 >> 3;
> +}
> +
> +static void st7586_from_rgb565(u8 *dst, void *vaddr,
> +			       struct drm_framebuffer *fb,
> +			       struct drm_clip_rect *clip)
> +{
> +	size_t len;
> +	unsigned int x, y;
> +	u16 *src, *buf;
> +	u8 val;
> +
> +	/* 3 pixels per byte, so grow clip to nearest multiple of 3 */
> +	clip->x1 = clip->x1 / 3 * 3;
> +	clip->x2 = (clip->x2 + 2) / 3 * 3;
> +	len = (clip->x2 - clip->x1) * sizeof(u16);
> +
> +	buf = kmalloc(len, GFP_KERNEL);
> +	if (!buf)
> +		return;
> +
> +	for (y = clip->y1; y < clip->y2; y++) {
> +		src = vaddr + (y * fb->pitches[0]);
> +		src += clip->x1;
> +		memcpy(buf, src, len);
> +		src = buf;
> +		for (x = clip->x1; x < clip->x2; x += 3) {
> +			val = st7586_rgb565_to_gray2(*src++) << 6;
> +			if (val & 0xC0)
> +				val |= 0x20;
> +			val |= st7586_rgb565_to_gray2(*src++) << 3;
> +			if (val & 0x18)
> +				val |= 0x04;
> +			val |= st7586_rgb565_to_gray2(*src++);
> +			*dst++ = ~val;
> +		}
> +	}
> +
> +	/* now adjust the clip so it applies to dst */
> +	clip->x1 /= 3;
> +	clip->x2 /= 3;
> +
> +	kfree(buf);
> +}
> +
> +static inline u8 st7586_xrgb8888_to_gray2(u32 rgb)
> +{
> +	u8 r = (rgb & 0x00ff0000) >> 16;
> +	u8 g = (rgb & 0x0000ff00) >> 8;
> +	u8 b = rgb & 0x000000ff;
> +	/* ITU BT.601: Y = 0.299 R + 0.587 G + 0.114 B */
> +	u8 gray8 = (3 * r + 6 * g + b) / 10;
> +
> +	return gray8 >> 6;
> +}
> +
> +static void st7586_from_xrgb8888(u8 *dst, void *vaddr,
> +				 struct drm_framebuffer *fb,
> +				 struct drm_clip_rect *clip)
> +{
> +	size_t len;
> +	unsigned int x, y;
> +	u32 *src, *buf;
> +	u8 val;
> +
> +	/* 3 pixels per byte, so grow clip to nearest multiple of 3 */
> +	clip->x1 = clip->x1 / 3 * 3;
> +	clip->x2 = (clip->x2 + 2) / 3 * 3;
> +	len = (clip->x2 - clip->x1) * sizeof(u32);
> +
> +	buf = kmalloc(len, GFP_KERNEL);
> +	if (!buf)
> +		return;
> +
> +	for (y = clip->y1; y < clip->y2; y++) {
> +		src = vaddr + (y * fb->pitches[0]);
> +		src += clip->x1;
> +		memcpy(buf, src, len);
> +		src = buf;
> +		for (x = clip->x1; x < clip->x2; x += 3) {
> +			val = st7586_xrgb8888_to_gray2(*src++) << 6;
> +			if (val & 0xC0)
> +				val |= 0x20;
> +			val |= st7586_xrgb8888_to_gray2(*src++) << 3;
> +			if (val & 0x18)
> +				val |= 0x04;
> +			val |= st7586_xrgb8888_to_gray2(*src++);
> +			*dst++ = ~val;
> +		}
> +	}
> +
> +	/* now adjust the clip so it applies to dst */
> +	clip->x1 /= 3;
> +	clip->x2 /= 3;
> +
> +	kfree(buf);
> +}

Please use tinydrm_xrgb8888_to_gray8().

> +
> +static int st7586_mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,

You can shorten your st7586_mipi_dbi_* to just st7586_*

> +				    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;
> +	struct drm_format_name_buf format_name;
> +	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;
> +	}
> +
> +	switch (fb->format->format) {
> +	case DRM_FORMAT_RGB565:
> +		st7586_from_rgb565(dst, src, fb, clip);
> +		break;
> +	case DRM_FORMAT_XRGB8888:
> +		st7586_from_xrgb8888(dst, src, fb, clip);
> +		break;
> +	default:
> +		dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
> +			     drm_get_format_name(fb->format->format,
> +						 &format_name));
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	if (import_attach)
> +		ret = dma_buf_end_cpu_access(import_attach->dmabuf,
> +					     DMA_FROM_DEVICE);
> +	return ret;
> +}
> +
> +static int st7586_mipi_dbi_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 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);
> +
> +	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_mipi_dbi_buf_copy(mipi->tx_buf, fb, &clip);
> +	if (ret)
> +		goto out_unlock;
> +
> +	/* NB: st7586_mipi_dbi_buf_copy() modifies clip */
> +
> +	mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS,
> +			 (clip.x1 >> 8) & 0xFF, clip.x1 & 0xFF,
> +			 (clip.x2 >> 8) & 0xFF, (clip.x2 - 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,
> +				   (clip.x2 - clip.x1) * (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_mipi_dbi_fb_funcs = {
> +	.destroy	= drm_fb_cma_destroy,
> +	.create_handle	= drm_fb_cma_create_handle,
> +	.dirty		= st7586_mipi_dbi_fb_dirty,
> +};
> +
> +void st7586_mipi_dbi_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;
> +
> +	DRM_DEBUG_KMS("\n");
> +
You should use this function to enable the regulator and init the
controller. Don't look at mi0283qt it should have been fixed.

> +	mipi->enabled = true;
> +	if (fb)

I don't think it's possible to enable the pipe without a framebuffer,
but I wasn't able find out. drm is complex...

> +		fb->funcs->dirty(fb, NULL, 0, 0, NULL, 0);
> +
> +	tinydrm_enable_backlight(mipi->backlight);
> +}
> +
> +static void st7586_mipi_dbi_blank(struct mipi_dbi *mipi)
> +{
> +	struct drm_device *drm = mipi->tinydrm.drm;
> +	u16 height = drm->mode_config.min_height;
> +	u16 width = (drm->mode_config.min_width + 2) / 3;
> +	size_t len = width * height;
> +
> +	memset(mipi->tx_buf, 0, len);
> +
> +	mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS, 0, 0,
> +			 (width >> 8) & 0xFF, (width - 1) & 0xFF);
> +	mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS, 0, 0,
> +			 (height >> 8) & 0xFF, (height - 1) & 0xFF);
> +	mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START,
> +			     (u8 *)mipi->tx_buf, len);
> +}
> +
> +static void st7586_mipi_dbi_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");
> +
> +	mipi->enabled = false;
> +
> +	if (mipi->backlight)
> +		tinydrm_disable_backlight(mipi->backlight);
> +	else
> +		st7586_mipi_dbi_blank(mipi);

And disable the regulator here.

> +}
> +
> +static const u32 st7586_mipi_dbi_formats[] = {
> +	DRM_FORMAT_RGB565,
> +	DRM_FORMAT_XRGB8888,

Why 2 emulation formats?
I chose DRM_FORMAT_XRGB8888 since I expected everything to support it.
Please use only that.

> +};
> +
> +static int st7586_mipi_dbi_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;
> +
> +	if (!mipi->command)
> +		return -EINVAL;

You know this is set after calling mipi_dbi_spi_init(), so you don't 
have to check.

> +
> +	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_mipi_dbi_fb_funcs, driver);
> +	if (ret)
> +		return ret;
> +
> +	ret = tinydrm_display_pipe_init(tdev, pipe_funcs,
> +					DRM_MODE_CONNECTOR_VIRTUAL,
> +					st7586_mipi_dbi_formats,
> +					ARRAY_SIZE(st7586_mipi_dbi_formats),
> +					mode, rotation);
> +	if (ret)
> +		return ret;
> +
> +	tdev->drm->mode_config.preferred_depth = 16;
> +	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 int st7586_init(struct mipi_dbi *mipi)
> +{
> +	struct tinydrm_device *tdev = &mipi->tinydrm;
> +	struct device *dev = tdev->drm->dev;
> +	u8 addr_mode;
> +	int ret;
> +
> +	DRM_DEBUG_KMS("\n");
> +
> +	ret = regulator_enable(mipi->regulator);
> +	if (ret) {
> +		dev_err(dev, "Failed to enable regulator %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* Avoid flicker by skipping setup if the bootloader has done it */
> +	if (mipi_dbi_display_is_on(mipi))

Looking at the datasheet it seems that it's not possible to read from
the controller via SPI?

> +		return 0;
> +
> +	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);
> +		regulator_disable(mipi->regulator);
> +		return ret;
> +	}
> +
> +	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);
> +
> +	return 0;
> +}
> +
> +static void st7586_fini(void *data)
> +{
> +	struct mipi_dbi *mipi = data;
> +
> +	DRM_DEBUG_KMS("\n");
> +	regulator_disable(mipi->regulator);
> +}
> +
> +static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
> +	.enable = st7586_mipi_dbi_pipe_enable,
> +	.disable = st7586_mipi_dbi_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 *dc;
> +	u32 rotation = 0;
> +	int ret;
> +
> +	mipi = devm_kzalloc(dev, sizeof(*mipi), GFP_KERNEL);
> +	if (!mipi)
> +		return -ENOMEM;
> +
> +	mipi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(mipi->reset)) {
> +		dev_err(dev, "Failed to get gpio 'reset'\n");
> +		return PTR_ERR(mipi->reset);
> +	}
> +
> +	dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW);
> +	if (IS_ERR(dc)) {
> +		dev_err(dev, "Failed to get gpio 'dc'\n");
> +		return PTR_ERR(dc);
> +	}
> +
> +	mipi->regulator = devm_regulator_get(dev, "power");
> +	if (IS_ERR(mipi->regulator))
> +		return PTR_ERR(mipi->regulator);
> +
> +	mipi->backlight = tinydrm_of_find_backlight(dev);
> +	if (IS_ERR(mipi->backlight))
> +		return PTR_ERR(mipi->backlight);
> +
> +	device_property_read_u32(dev, "rotation", &rotation);
> +
> +	ret = mipi_dbi_spi_init(spi, mipi, dc);
> +	if (ret)
> +		return ret;

Since you are using mipi_dbi_debugfs_init and the controller can't be
read, disable reading:

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_mipi_dbi_init(&spi->dev, mipi, &st7586_pipe_funcs,
> +				   &st7586_driver, &st7586_mode, rotation);
> +	if (ret)
> +		return ret;
> +
> +	ret = st7586_init(mipi);

This isn't necessary when you use .enable/.disable to control power/init,
and you can drop the devm_add_action.

> +	if (ret)
> +		return ret;
> +
> +	/* use devres to fini after drm unregister (drv->remove is before) */
> +	ret = devm_add_action(dev, st7586_fini, mipi);
> +	if (ret) {
> +		st7586_fini(mipi);
> +		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 int __maybe_unused st7586_pm_suspend(struct device *dev)
> +{
> +	struct mipi_dbi *mipi = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = tinydrm_suspend(&mipi->tinydrm);
> +	if (ret)
> +		return ret;
> +
> +	st7586_fini(mipi);
> +

With .enable/.disable controlling power, tinydrm_suspend() is enough.

> +	return 0;
> +}
> +
> +static int __maybe_unused st7586_pm_resume(struct device *dev)
> +{
> +	struct mipi_dbi *mipi = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = st7586_init(mipi);
> +	if (ret)
> +		return ret;
> +

Same goes here.

> +	return tinydrm_resume(&mipi->tinydrm);
> +}
> +
> +static const struct dev_pm_ops st7586_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(st7586_pm_suspend, st7586_pm_resume)
> +};
> +
> +static struct spi_driver st7586_spi_driver = {
> +	.driver = {
> +		.name = "st7586",
> +		.owner = THIS_MODULE,
> +		.of_match_table = st7586_of_match,
> +		.pm = &st7586_pm_ops,
> +	},
> +	.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@...hnology.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/drm/tinydrm/st7586.h b/include/drm/tinydrm/st7586.h
> new file mode 100644
> index 0000000..18fb56b
> --- /dev/null
> +++ b/include/drm/tinydrm/st7586.h

Please put this in drivers/drm/tinydrm, or you can even put the defines
in the driver if you want, it's quite short.
ili9341.h shouldn't have ended up in include/drm/tinydrm.

Noralf.

> @@ -0,0 +1,34 @@
> +/*
> + * ST7586 LCD controller
> + *
> + * Copyright (C) 2017 David Lechner <david@...hnology.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.
> + */
> +
> +#ifndef __LINUX_ST7856_H
> +#define __LINUX_ST7856_H
> +
> +#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)
> +
> +#endif /* __LINUX_ST7856_H */

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