RE: [PATCH 1/4] clk: renesas: rzv2h-cpg: Add support for coupled clock

[Stephen Boyd <sboyd@kernel.org>]

Quoting Biju Das (2025-03-14 00:18:33)
> Hi Stephen,
> 
> > -----Original Message-----
> > From: Biju Das
> > Sent: 07 March 2025 07:02
> > Subject: RE: [PATCH 1/4] clk: renesas: rzv2h-cpg: Add support for coupled clock
> > 
> > Hi Stephen,
> > 
> > > -----Original Message-----
> > > From: Stephen Boyd <sboyd@kernel.org>
> > > Sent: 06 March 2025 22:37
> > > Subject: RE: [PATCH 1/4] clk: renesas: rzv2h-cpg: Add support for
> > > coupled clock
> > >
> > > Quoting Biju Das (2025-03-06 02:10:50)
> > > > > From: Stephen Boyd <sboyd@kernel.org> Quoting Biju Das (2025-03-03
> > > > > 03:04:19)
> > > > > > The spi and spix2 clk share same bit for clock gating. Add
> > > > > > support for coupled clock with checking the monitor bit for both the clocks.
> > > > >
> > > > > Could you add an intermediate parent clk of both spi and spix2
> > > > > that only handles the enable bit for clock gating? Then the enable
> > > > > count handling would be in the core
> > > clk code.
> > > >
> > > > The parent clock rate of spi and spix2 are different. If we use an
> > > > intermediate parent clk, What clk rate the parent will use??
> > >
> > > Alright, got it. Does the consumer care about the difference between the two clks for the gating
> > part?
> > 
> > Although gating bit is same, for some reason their monitor bit is different. So, to confirm clk on
> > status we need to check respective monitor bits. Parallelly, I will check with hardware team, does it
> > need to monitor both these bits??
> 
> According to hardware team, the spix2 clock is twice the frequency of the spi clock, and the clock ON/OFF
> period displayed for each bit in the monitor register varies slightly due to the difference in frequency.
> 
> So to check the status after changing the clock ON/OFF register setting,
> please check the two monitor register bits together
> 

That answers the hardware side of the question. Why does software need
to care that they're two different things vs. one clk?