lkml.org 
[lkml]   [2018]   [Aug]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: [PATCH 2/2] clk: imx: imx7d: remove clks_init_on array
Date
Quoting Peng Fan (2018-08-12 18:15:41)
> Hi Anson,
>
> > > > -----Original Message-----
> > > > From: Anson Huang
> > > > Sent: 2018年8月8日 12:39
> > > > To: shawnguo@kernel.org; s.hauer@pengutronix.de;
> > > > kernel@pengutronix.de; Fabio Estevam <fabio.estevam@nxp.com>;
> > > > mturquette@baylibre.com; sboyd@kernel.org;
> > > > linux-arm-kernel@lists.infradead.org;
> > > > linux-clk@vger.kernel.org; linux-kernel@vger.kernel.org
> > > > Cc: dl-linux-imx <linux-imx@nxp.com>
> > > > 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?

\
 
 \ /
  Last update: 2018-08-31 03:30    [W:0.068 / U:4.348 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site