• Noralf Trønnes's avatar
    drm/tinydrm: Remove tinydrm_spi_max_transfer_size() · e143364b
    Noralf Trønnes authored
    spi-bcm2835 can handle >64kB buffers now so there is no need to check
    ->max_dma_len. The tinydrm_spi_max_transfer_size() max_len argument is
    not used by any callers, so not needed.
    
    Then we have the spi_max module parameter. It was added because
    staging/fbtft has support for it and there was a report that someone used
    it to set a small buffer size to avoid popping on a USB soundcard on a
    Raspberry Pi. In hindsight it shouldn't have been added, I should have
    waited for it to become a problem first. I don't know it anyone is
    actually using it, but since tinydrm_spi_transfer() is being moved to
    mipi-dbi, I'm taking the opportunity to remove it. I'll add it back to
    mipi-dbi if someone complains.
    
    With that out of the way, spi_max_transfer_size() can be used instead.
    
    The chosen 16kB buffer size for Type C Option 1 (9-bit) interface is
    somewhat arbitrary, but a bigger buffer will have a miniscule impact on
    transfer speed, so it's probably fine.
    Acked-by: default avatarSam Ravnborg <sam@ravnborg.org>
    Signed-off-by: default avatarNoralf Trønnes <noralf@tronnes.org>
    Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-6-noralf@tronnes.org
    e143364b
tinydrm-helpers.c 2.21 KB