bbdc00a7de
The rk3288 SoC has two PWM implementations available, the "old" implementation and the "new" one. You can switch between the two of them by flipping a bit in the grf. The "old" implementation is the default at chip power up but isn't the one that's officially supposed to be used. ...and, in fact, the driver that gets selected in Linux using the rk3288 device tree only supports the "new" implementation. Long ago I tried to get a switch to the right IP block landed in the PWM driver (search for "rk3288: Switch to use the proper PWM IP") but that got rejected. In the mean time the grf has grown a full-fledged driver that already sets other random bits like this. That means we can now get the fix landed. For those wondering how things could have possibly worked for the last 4.5 years, folks have mostly been relying on the bootloader to set this bit. ...but occasionally folks have pointed back to my old patch series [1] in downstream kernels. [1] https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1391597.html Signed-off-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
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.