Re: [PATCH v4 4/7] cpufreq: add driver for Raspberry Pi
From: Viresh Kumar
Date: Thu Jun 13 2019 - 12:56:43 EST
On 12-06-19, 20:24, Nicolas Saenz Julienne wrote:
> Raspberry Pi's firmware offers and interface though which update it's
> performance requirements. It allows us to request for specific runtime
> frequencies, which the firmware might or might not respect, depending on
> the firmware configuration and thermals.
>
> As the maximum and minimum frequencies are configurable in the firmware
> there is no way to know in advance their values. So the Raspberry Pi
> cpufreq driver queries them, builds an opp frequency table to then
> launch cpufreq-dt.
>
> Also, as the firmware interface might be configured as a module, making
> the cpu clock unavailable during init, this implements a full fledged
> driver, as opposed to most drivers registering cpufreq-dt, which only
> make use of an init routine.
>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
> Acked-by: Eric Anholt <eric@xxxxxxxxxx>
> Reviewed-by: Stephen Boyd <sboyd@xxxxxxxxxx>
Applied. Thanks.
--
viresh