1d7796bdb6
Added support for dynamic clock freq configuration in PWM kernel driver.
Earlier the PWM driver used to cache boot time clock rate by PWM clock
parent during probe. Hence dynamically changing PWM frequency was not
possible for all the possible ranges. With this change, dynamic
calculation is enabled and it is able to set the requested period from
sysfs knob provided the value is supported by clock source.
Changes mainly have 2 parts:
- Tegra186 and later chips [1]
- Tegra210 and prior chips [2]
For [1] - Changes implemented to set pwm period dynamically and also
checks added to allow only if requested period(ns) is below or
equals to higher range.
For [2] - Only checks if the requested period(ns) is below or equals to
higher range defined by max clock limit. The limitation in
Tegra210 or prior chips are due to the reason of having only
one PWM controller supporting multiple channels. But later
chips have multiple PWM controller instances each having
single channel support.
Signed-off-by: Sandipan Patra <spatra@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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.