Commit graph

6 commits

Author SHA1 Message Date
Simon Glass
e70cc43831 dm: clk: Add support for decoding clocks from the device tree
Add a method which can locate a clock for a device, given its index. This
uses the normal device tree bindings to return the clock device and the
first argument which is normally used as a peripheral ID in U-Boot.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2016-01-21 19:47:29 -07:00
Masahiro Yamada
f0e075162f clk: add API to enable clock
The most basic thing for clock is to enable it, but it is missing
in this uclass.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>
2016-01-20 19:06:23 -07:00
Masahiro Yamada
ad1cf78585 clk: add needed include and declaration to include/clk.h
This header uses ulong, so it needs to include <linux/types.h>.
Likewise, "struct udevice" must be declared before it is used.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>
2016-01-20 19:06:23 -07:00
Masahiro Yamada
8bdf9cfda0 clk: fix comments in include/clk.h
The comment about get_periph_rate() is the same as that of
set_periph_rate().

I am fixing typos here and there while I am in this file.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>
2016-01-20 19:06:23 -07:00
Simon Glass
f26c8a8e77 dm: Add a clock uclass
Clocks are an important feature of platforms and have become increasing
complex with time. Most modern SoCs have multiple PLLs and dozens of clock
dividers which distribute clocks to on-chip peripherals.

Some SoC implementations have a clock API which is private to that SoC family,
e.g. Tegra and Exynos. This is useful but it would be better to have a
common API that can be understood and used throughout U-Boot.

Add a simple clock API as a starting point. It supports querying and setting
the rate of a clock. Each clock is a device. To reduce memory and processing
overhead the concept of peripheral clocks is provided. These do not need to
be explicit devices - it is possible to write a driver that can adjust the
I2C clock (for example) without an explicit I2C clock device. This can
dramatically reduce the number of devices (and associated overhead) in a
complex SoC.

Clocks are referenced by a number, and it is expected that SoCs will define
that numbering themselves via an enum.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-07-21 17:39:29 -06:00
Michal Simek
08d0d6f32e common: Add new clk command
Command provides just dump subcommand for showing clock
frequencies in a soc.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Stefano Babic <sbabic@denx.de>
2014-02-04 16:32:20 +01:00