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  1. Dec 19, 2014
    • Gregory Nutt's avatar
      7a874e5d
    • Gregory Nutt's avatar
      stm32: implements ltdc frambuffer and support for ltdc layer operation · 4ac49f51
      Gregory Nutt authored
      
      
      This implements the framebuffer support for the generic nuttx framebuffer
      interface, (see nuttx/video/fb.h)
      
      This also implements the interface to perform hardware accelerated layer
      operation by the ltdc controller and dma2d controller later (see
      nuttx/video/ltdc.h).
      
      The following methods are supported by the ltdc interface:
      
      - getvideoinfo
        Get video information of the layer
      
      - getplaneinfo
        Get plane information of the layer
      
      - getlid
        Handle specific layer identifier. This allows to detect to current layer
        state (e.g. important for layer flipping)
      
      - setclut
        Set the layer color lookup table. Up to 256 color entries supported.
      
      - getclut
        Get the layer color lookup table
      
      - setcolor
        Set the default layer color. In the context of the ltdc layer this means set
        the default color outside the active area or if the layer is disabled.
      
      - getcolor
        Get the default layer color
      
      - setcolorkey
        Set the layer colorkey (chromakey). Colorkey is enabled by blendmode
        LTDC_BLEND_COLORKEY
      
      - getcolorkey
        Get the layer colorkey
      
      - setalpha
        Set the constant alpha value. If blend mode LTDC_BLEND_SRCPIXELALPHA or
        LTDC_BLEND_DESTPIXELALPHA is defined than the blended color is calculated
        by the formel:
          Cdest = Pixelalpha * Constalpha * Csrc.
        Otherwise:
          Cest = Constalpha * Csrc
      
      - getalpha
        get the alpha value
      
      - setblendmode
        Set the layer blendmode.
        Supported blendmodes:
          non blendmode (do not perform blend operation independent on the layers
                         alpha and colorkey)
          alpha          alpha blending (transparency)
          destpixelalpha use pixel alpha value for the top layer (Layer2)
          srcpixelalpha  use pixel alpha value for the subjacent layer (Layer1)
          colorkey       enable colorkey
      
      - getblendmode
        Get the layer blendmode
      
      - setarea
        Set the active layer area, the visible rectangle inside the whole layer.
        This also allows to change the position of the whole layer which is visible in
        the selected area independent on the area position.
      
      - getarea
        Get the active layer area
      
      - update
        Reload the layer shadow register and make changes visible. Also supports
        layer flipping.
      
      Note! Dithering and background color are static parameter and can only changed
      at build time.
      
      Implementation details:
      
      The implementation of ltdc interface was inspired by SDL and DirectFB.
      All layer settings are shadowed before they become active (except setclut).
      They are still inactive until the layer is updated. This is done by the update
      method. Should clut only active after an update or not? Clut is used for drawing
      while the other settings usually used for blend or blit operations. So i think
      this should be the right way.
      
      The implementation of ltdc interface was inspired by SDL and DirectFB.
      All layer settings shadowed before they become active (except clut).
      They are still inactive until the layer is updated. This is done by the update
      call. Should clut only activated after an update or not? Clut is used for draw
      operation while the other settings usually used for blend or blit operations.
      So i think this should be the right way.
      
      Deviations from the ltdc hardware implementation:
      
      - Shadow register update of both layer (Layer1 or Layer2) is independent as long
        LTDC_UPDATE_SIM is not set. This flag allows to update both layer simultaneous.
        Otherwise only the desired layer is updated.
      
      Layer operation:
      
      Keep in mind, both layer are allways active (of course if both enabled by the
      configuration). First the Layer 1 is blended with the background color and the
      result is blended with the Layer2. To avoid blend effects, set the Layer2 in non
      blend mode. This is equal to blend with alpha = 255. Enable blending of Layer2
      with the background color by enable blending of Layer1 and disable the opacity
      by setting the alpha value to 0.
      
      Layer flip:
      
      A layer flip usual mean swapping two framebuffer. So the current inactive buffer
      can refreshed with data while the active framebuffer is visible. A flip
      operation changes the inactive layer to the active one and vice versa.
      
      The ltdc implementation supports layer flip. This can be done by the update call
      and the flag LTDC_UPDATE_FLIP. In this case ltdc makes the inactive layer
      invisible. In detail, the inactive layer is disabled and the blendmode reset.
      Detection of the current layer state (e.g. active or inactive) is supported
      by the getlid method combined with one of the LTDC_LAYER_* flags.
      Maybe an additional method "flip" for flip operation should be added to the ltdc
      interface? But this make no sence from my view if the layer is a non LTDC layer,
      e.g. playing with dma2d only.
      
      Supported and tested nuttx pixel formats:
      
      Single Layer without LTDC interface support:
      - FB_FMT_RGB8 (cmap support required)
      - FB_FMT_RGB16_565
      - FB_FMT_RGB24
      
      Single Layer with LTDC interface support:
      - FB_FMT_RGB8 (cmap support required)
      - FB_FMT_RGB16_565
      - FB_FMT_RGB24
      
      Dual Layer with LTDC interface support:
      - FB_FMT_RGB8 (cmap support required)
      - FB_FMT_RGB16_565
      - FB_FMT_RGB24
      
      Why is FB_FMT_ARGB8888 missing?
      
      Changes:
      - Remove unused register debug method.
      
      Todo:
      - Add support for backlight, currently not neccessary
      
      Did i forgot something? Take a look in the ltdc example or the interface
      description (see nuttx/include/video/ltdc.h).
      
      Thanks to Ken for the base layout. ;)
      
      Signed-off-by: default avatarMarco Krahl <ocram.lhark@gmail.com>
      4ac49f51
    • Gregory Nutt's avatar
      stm32: Add interface description for ltdc controller. This defines the... · 3ce3b168
      Gregory Nutt authored
      
      stm32: Add interface description for ltdc controller.  This defines the interface to perform hardware accelerated layer operation by the ltdc controller.
      
      The following methods must be supported by the implementation:
      
      - gevideoinfo
      - getplaneinfo
      - getlid
      - setclut
      - getclut
      - setcolor
      - getcolor
      - setcolorkey
      - getcolorkey
      - setalpha
      - getalpha
      - setblendmode
      - getblendmode
      - setarea
      - getarea
      - update
      
      And if DMA2D is supported:
      
      - blit
      - blend
      
      The method up_ltdcgetlayer provides access to a reference of a specific ltdc
      layer.
      
      Signed-off-by: default avatarMarco Krahl <ocram.lhark@gmail.com>
      3ce3b168
    • Gregory Nutt's avatar
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    • Gregory Nutt's avatar
      stm32: Add common stm32 layer description. This defines a common layer... · 7edfddfc
      Gregory Nutt authored
      
      stm32: Add common stm32 layer description. This defines a common layer description for the ltdc and dma2d controller.
      
      Signed-off-by: default avatarMarco Krahl <ocram.lhark@gmail.com>
      7edfddfc
    • Gregory Nutt's avatar
      stm32f429i-disco: update board definition for the ili9341 LCD display. This... · dd51c8db
      Gregory Nutt authored
      
      stm32f429i-disco: update board definition for the ili9341 LCD display. This configures all LCD settings for the RGB interface. Also adds a customer LCD display template.
      
      Signed-off-by: default avatarMarco Krahl <ocram.lhark@gmail.com>
      dd51c8db
    • Gregory Nutt's avatar
    • Gregory Nutt's avatar
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    • Gregory Nutt's avatar
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  2. Dec 18, 2014
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