mirror of
https://github.com/hardkernel/linux.git
synced 2026-06-05 18:41:58 +09:00
9854881c22
[ Upstream commit 7ff0b53c40 ]
The spi_master.setup() callback must not change configuration registers,
as that could corrupt I/O that is in progress for other SPI slaves.
The only exception is the configuration of the native chip select
polarity in SPI master mode, as a wrong chip select polarity will cause
havoc during all future transfers to any other SPI slave.
Hence stop writing to registers in sh_msiof_spi_setup(), unless it is
the first call for a controller using a native chip select, or unless
native chip select polarity has changed (note that you'll loose anyway
if I/O is in progress). Even then, only do what is strictly necessary,
instead of calling sh_msiof_spi_set_pin_regs().
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.