e143364b4c
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: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Noralf Trønnes <noralf@tronnes.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-6-noralf@tronnes.org
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.