Re: [PATCH v2 20/91] clk: bcm: rpi: Discover the firmware clocks

From: Stephen Boyd
Date: Wed May 27 2020 - 03:03:21 EST


Quoting Maxime Ripard (2020-04-24 08:34:01)
> The RaspberryPi4 firmware actually exposes more clocks than are currently
> handled by the driver and we will need to change some of them directly
> based on the pixel rate for the display related clocks, or the load for the
> GPU.
>
> This rate change can have a number of side-effects, including adjusting the
> various PLL voltages or the PLL parents. The firmware will also update
> those clocks by itself for example if the SoC runs too hot.
>
> In order to make Linux play as nice as possible with those constraints, it
> makes sense to rely on the firmware clocks as much as possible.
>
> Fortunately,t he firmware has an interface to discover the clocks it

Fortunately, the

> exposes.
>
> Let's use it to discover, register the clocks in the clocks framework and
> then expose them through the device tree for consumers to use them.
>
> Cc: Michael Turquette <mturquette@xxxxxxxxxxxx>
> Cc: Stephen Boyd <sboyd@xxxxxxxxxx>
> Cc: linux-clk@xxxxxxxxxxxxxxx
> Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
> ---

Reviewed-by: Stephen Boyd <sboyd@xxxxxxxxxx>