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drm/tinydrm: Add tinydrm_xrgb8888_to_gray8() helper 

Drm has no monochrome or greyscale support so add a conversion
from the common format XR24.

Also reorder includes into the common order.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1496934875-51984-4-git-send-email-noralf@tronnes.org
This commit is contained in:
Noralf Trønnes 2017-06-08 17:14:34 +02:00
parent 7f0dc77772
commit 379ea9a1a5
2 changed files with 73 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

74
drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
View File

@ -7,13 +7,15 @@
* (at your option) any later version.
*/
#include <drm/tinydrm/tinydrm.h>
#include <drm/tinydrm/tinydrm-helpers.h>
#include <linux/backlight.h>
#include <linux/dma-buf.h>
#include <linux/pm.h>
#include <linux/spi/spi.h>
#include <linux/swab.h>
#include <drm/tinydrm/tinydrm.h>
#include <drm/tinydrm/tinydrm-helpers.h>
static unsigned int spi_max;
module_param(spi_max, uint, 0400);
MODULE_PARM_DESC(spi_max, "Set a lower SPI max transfer size");
@ -180,6 +182,74 @@ void tinydrm_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
}
EXPORT_SYMBOL(tinydrm_xrgb8888_to_rgb565);
/**
* tinydrm_xrgb8888_to_gray8 - Convert XRGB8888 to grayscale
* @dst: 8-bit grayscale destination buffer
* @fb: DRM framebuffer
*
* Drm doesn't have native monochrome or grayscale support.
* Such drivers can announce the commonly supported XR24 format to userspace
* and use this function to convert to the native format.
*
* Monochrome drivers will use the most significant bit,
* where 1 means foreground color and 0 background color.
*
* ITU BT.601 is used for the RGB -> luma (brightness) conversion.
*
* Returns:
* Zero on success, negative error code on failure.
*/
int tinydrm_xrgb8888_to_gray8(u8 *dst, struct drm_framebuffer *fb)
{
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;
unsigned int x, y, pitch = fb->pitches[0];
int ret = 0;
void *buf;
u32 *src;
if (WARN_ON(fb->format->format != DRM_FORMAT_XRGB8888))
return -EINVAL;
/*
* The cma memory is write-combined so reads are uncached.
* Speed up by fetching one line at a time.
*/
buf = kmalloc(pitch, GFP_KERNEL);
if (!buf)
return -ENOMEM;
if (import_attach) {
ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
DMA_FROM_DEVICE);
if (ret)
goto err_free;
}
for (y = 0; y < fb->height; y++) {
src = cma_obj->vaddr + (y * pitch);
memcpy(buf, src, pitch);
src = buf;
for (x = 0; x < fb->width; x++) {
u8 r = (*src & 0x00ff0000) >> 16;
u8 g = (*src & 0x0000ff00) >> 8;
u8 b = *src & 0x000000ff;
/* ITU BT.601: Y = 0.299 R + 0.587 G + 0.114 B */
*dst++ = (3 * r + 6 * g + b) / 10;
src++;
}
}
if (import_attach)
ret = dma_buf_end_cpu_access(import_attach->dmabuf,
DMA_FROM_DEVICE);
err_free:
kfree(buf);
return ret;
}
EXPORT_SYMBOL(tinydrm_xrgb8888_to_gray8);
/**
* tinydrm_of_find_backlight - Find backlight device in device-tree
* @dev: Device

1
include/drm/tinydrm/tinydrm-helpers.h
View File

@ -43,6 +43,7 @@ void tinydrm_swab16(u16 *dst, void *vaddr, struct drm_framebuffer *fb,
void tinydrm_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
struct drm_framebuffer *fb,
struct drm_clip_rect *clip, bool swap);
int tinydrm_xrgb8888_to_gray8(u8 *dst, struct drm_framebuffer *fb);
struct backlight_device *tinydrm_of_find_backlight(struct device *dev);
int tinydrm_enable_backlight(struct backlight_device *backlight);