diff options
Diffstat (limited to 'drivers/gpu/drm/tinydrm')
| -rw-r--r-- | drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c | 74 |
1 files changed, 72 insertions, 2 deletions
diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c index d4cda3308ac7..75808bb84c9a 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 * |