Re: [GIT PULL] Greybus driver subsystem for 4.9-rc1

From: Bryan O'Donoghue
Date: Thu Sep 15 2016 - 06:59:40 EST


On Thu, 2016-09-15 at 12:17 +0200, Greg KH wrote:
> This
> > is the first I've heard of timesync having a binding. I can't
> imagine
> > why it needs one.
>
> Ah, I'll let Bryan answer that one :)

It's possible we could drop the binding. It was needed to describe the
register location of the MMIO architectural register on MSM8994. I have
this binding ATM the describe fact that get_cycles() on MSM8994 returns
a free-running counter, clocked by refclk and that refclk is provided
to each processor that want to do FrameTime - i.e. the clock driving
get_cycles() comes from PMIC and drives the relevant PLLs on the
downstream processors clocking their respective TMR blocks.

static const struct of_device_id arch_timer_of_match[] = {
ÂÂÂÂÂÂÂÂ{ .compatibleÂÂÂ= "google,greybus-frame-time-counter", },
ÂÂÂÂÂÂÂÂ{},
};

I'm not aware of a corresponding kernel API that describes the
frequency get_cycles() operates at but if there is one then there's no
need for this binding.