RE: [PATCH 2/2] clk: imx: imx7d: remove clks_init_on array

[Stephen Boyd]

Quoting Peng Fan (2018-08-12 18:15:41)
> Hi Anson,
> 
> > > > -----Original Message-----
> > > > From: Anson Huang
> > > > Sent: 2018å8æ8æ 12:39
> > > > To: shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx;
> > > > kernel@xxxxxxxxxxxxxx; Fabio Estevam <fabio.estevam@xxxxxxx>;
> > > > mturquette@xxxxxxxxxxxx; sboyd@xxxxxxxxxx;
> > > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> > > > linux-clk@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> > > > Cc: dl-linux-imx <linux-imx@xxxxxxx>
> > > > Subject: [PATCH 2/2] clk: imx: imx7d: remove clks_init_on array
> > > >
> > > > Clock framework will enable those clocks registered with
> > > > CLK_IS_CRITICAL flag, so no need to have clks_init_on array during
> > > > clock
> > > initialization now.
> > >
> > > Will it be more flexible to parse dts saying "critical-clocks = <xxx>"
> > > or "init-on-arrary=<xxx>"
> > > and enable those clocks?
> > 
> > Parsing the clocks arrays from dtb is another way of enabling critical clocks, but
> > for current i.MX6/7 platforms, we implement it in same way as most of other
> > SoCs, currently I did NOT see any necessity of putting them in dtb, just adding
> > flag during clock registering is more simple, if there is any special requirement
> > for different clocks set to be enabled, then we can add support to enable the
> > method of parsing critical-clocks from dtb. Just my two cents.
> 
> Thinking about OP-TEE want to use one device, but it's clocks are registered
> by Linux, because there is no module in Linux side use it, it will shutdown the clock,
> which cause OP-TEE could not access the device.
> 
> Then people have to modify clk code to add CLK_IS_CRITICAL flag to make sure
> the clocks are not shutdown by Linux.
> 
> However adding a new property in clk node and let driver code parse the dts,
> there is no need to modify clk driver code when OP-TEE needs another device clock.
> 

If OP-TEE needs linux to keep things on then why can't the OP-TEE driver
in Linux probe, acquire clocks, and keep the clks enabled forever?