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

[Stephen Boyd]

Quoting Jerome Forissier (2018-08-31 01:01:44)
> 
> 
> On 08/31/2018 03:29 AM, Stephen Boyd wrote:
> > 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?
> 
> Sounds reasonable, but how could this be done without introducing
> platform-specific stuff in the OP-TEE driver?
> 

Why is that a goal?