linux-kernel - RE: [PATCH V4 2/2] clk: scmi: support state_ctrl

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Date: Sun, 18 Feb 2024 02:19:45 +0000
From: Peng Fan <peng.fan@....com>
To: Sudeep Holla <sudeep.holla@....com>, "Peng Fan (OSS)"
	<peng.fan@....nxp.com>, "sboyd@...nel.org" <sboyd@...nel.org>
CC: "cristian.marussi@....com" <cristian.marussi@....com>,
	"mturquette@...libre.com" <mturquette@...libre.com>,
	"linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "linux-clk@...r.kernel.org"
	<linux-clk@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: RE: [PATCH V4 2/2] clk: scmi: support state_ctrl_forbidden

> Subject: Re: [PATCH V4 2/2] clk: scmi: support state_ctrl_forbidden
> 
> On Sun, Jan 21, 2024 at 07:09:01PM +0800, Peng Fan (OSS) wrote:
> > From: Peng Fan <peng.fan@....com>
> >
> > Some clocks may exported to linux, while those clocks are not allowed
> > to configure by Linux. For example:
> >
> > SYS_CLK1-----
> >              \
> > 	     --MUX--->MMC1_CLK
> >              /
> > SYS_CLK2-----
> >
> > MMC1 needs set parent, so SYS_CLK1 and SYS_CLK2 are exported to Linux,
> > then the clk propagation will touch SYS_CLK1 or SYS_CLK2.
> > So we need bypass the failure for SYS_CLK1 or SYS_CLK2 when enable the
> > clock of MMC1, adding scmi_no_state_ctrl_clk_ops to use software
> > enable counter, while not calling scmi api.
> >
> 
> I would rewrite the commit message something like:
> "
>     clk: scmi: Add support for forbidden clock state controls
> 
>     Some clocks may be exported to OS agent, while certain configurations/
>     access to those clocks are restricted to the OS agent by the SCMI platform
>     firmware. For example:
> 
>     SYS_CLK1-----
>                  \
>                  --MUX--->MMC1_CLK
>                  /
>     SYS_CLK2-----
> 
>     MMC1_CLK needs to set parent as part of it initialisation and enabling.
>     SYS_CLK1 and SYS_CLK2 are exported to the OS agent. The clk propagation
>     will access SYS_CLK1 or SYS_CLK2 based on the configuration. However,
>     we need bypass the failure to access SYS_CLK1 or SYS_CLK2 when
> MMC1_CLK
>     is accessed and enabled.
> 
>     Add a separate scmi_no_state_ctrl clk_ops where the calls to the SCMI
>     platform firmware are avoided if the access is not permitted.
> "
> No need to repost.
> 
> I need Stephen's ack to take this together with scmi clk changes.

Stephen, 

would you please ack if you are ok?

Thanks,
Peng.

> 
> --
> Regards,
> Sudeep