The current approach of using uclass_get_device() is error-prone. Another
clock (for example a fixed-clock) may cause it to break. Add a function that
does a proper search.
Signed-off-by: Simon Glass <sjg@chromium.org>
At present we use the same peripheral ID for clocks and pinctrl. While this
works it is probably better to use the device tree clock binding ID for
clocks. We can use the clk_get_by_index() function to find this.
Update the clock drivers and the code that uses them.
Signed-off-by: Simon Glass <sjg@chromium.org>
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>
This commit intends to implement "fixed-clock" as in Linux.
(drivers/clk/clk-fixed-rate.c in Linux)
If you need a very simple clock to just provide fixed clock rate
like a crystal oscillator, you do not have to write a new driver.
This driver can support it.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>
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>
Add a driver for setting up and modifying the various PLLs, peripheral
clocks and mmc clocks on RK3036
Signed-off-by: Lin Huang <hl@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>
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>
