Drm has no monochrome or greyscale support so add a conversion
from the common format XR24.
Also reorder includes into the common order.
Signed-off-by: Noralf Trønnes <nor...@tronnes.org>
---
drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c | 74 +++++++++++++++++++++++++-
include/drm/tinydrm/tinydrm-helpers.h | 1 +
2 files changed, 73 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
index d4cda33..75808bb 100644
--- a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
+++ b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
@@ -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");
@@ -181,6 +183,74 @@ 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
*
diff --git a/include/drm/tinydrm/tinydrm-helpers.h
b/include/drm/tinydrm/tinydrm-helpers.h
index 9b9b6cf..a6c387f 100644
--- a/include/drm/tinydrm/tinydrm-helpers.h
+++ b/include/drm/tinydrm/tinydrm-helpers.h
@@ -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);
--
2.7.4
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