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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
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2 changed files with 73 additions and 2 deletions
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@ -7,13 +7,15 @@
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* (at your option) any later version.
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*/
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#include <drm/tinydrm/tinydrm.h>
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#include <drm/tinydrm/tinydrm-helpers.h>
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#include <linux/backlight.h>
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#include <linux/dma-buf.h>
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#include <linux/pm.h>
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#include <linux/spi/spi.h>
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#include <linux/swab.h>
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#include <drm/tinydrm/tinydrm.h>
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#include <drm/tinydrm/tinydrm-helpers.h>
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static unsigned int spi_max;
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module_param(spi_max, uint, 0400);
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MODULE_PARM_DESC(spi_max, "Set a lower SPI max transfer size");
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@ -180,6 +182,74 @@ void tinydrm_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
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}
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EXPORT_SYMBOL(tinydrm_xrgb8888_to_rgb565);
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/**
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* tinydrm_xrgb8888_to_gray8 - Convert XRGB8888 to grayscale
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* @dst: 8-bit grayscale destination buffer
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* @fb: DRM framebuffer
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*
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* Drm doesn't have native monochrome or grayscale support.
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* Such drivers can announce the commonly supported XR24 format to userspace
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* and use this function to convert to the native format.
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*
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* Monochrome drivers will use the most significant bit,
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* where 1 means foreground color and 0 background color.
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*
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* ITU BT.601 is used for the RGB -> luma (brightness) conversion.
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*
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* Returns:
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* Zero on success, negative error code on failure.
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*/
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int tinydrm_xrgb8888_to_gray8(u8 *dst, struct drm_framebuffer *fb)
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{
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struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
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struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
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unsigned int x, y, pitch = fb->pitches[0];
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int ret = 0;
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void *buf;
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u32 *src;
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if (WARN_ON(fb->format->format != DRM_FORMAT_XRGB8888))
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return -EINVAL;
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/*
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* The cma memory is write-combined so reads are uncached.
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* Speed up by fetching one line at a time.
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*/
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buf = kmalloc(pitch, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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if (import_attach) {
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ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
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DMA_FROM_DEVICE);
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if (ret)
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goto err_free;
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}
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for (y = 0; y < fb->height; y++) {
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src = cma_obj->vaddr + (y * pitch);
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memcpy(buf, src, pitch);
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src = buf;
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for (x = 0; x < fb->width; x++) {
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u8 r = (*src & 0x00ff0000) >> 16;
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u8 g = (*src & 0x0000ff00) >> 8;
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u8 b = *src & 0x000000ff;
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/* ITU BT.601: Y = 0.299 R + 0.587 G + 0.114 B */
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*dst++ = (3 * r + 6 * g + b) / 10;
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src++;
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}
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}
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if (import_attach)
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ret = dma_buf_end_cpu_access(import_attach->dmabuf,
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DMA_FROM_DEVICE);
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err_free:
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kfree(buf);
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return ret;
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}
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EXPORT_SYMBOL(tinydrm_xrgb8888_to_gray8);
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/**
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* tinydrm_of_find_backlight - Find backlight device in device-tree
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* @dev: Device
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@ -43,6 +43,7 @@ void tinydrm_swab16(u16 *dst, void *vaddr, struct drm_framebuffer *fb,
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void tinydrm_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
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struct drm_framebuffer *fb,
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struct drm_clip_rect *clip, bool swap);
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int tinydrm_xrgb8888_to_gray8(u8 *dst, struct drm_framebuffer *fb);
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struct backlight_device *tinydrm_of_find_backlight(struct device *dev);
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int tinydrm_enable_backlight(struct backlight_device *backlight);
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