Anson Huang Best Regards!
> -----Original Message----- > From: Stephen Boyd <sb...@kernel.org> > Sent: Saturday, September 1, 2018 1:58 AM > To: ker...@pengutronix.de; linux-arm-ker...@lists.infradead.org; > linux-...@vger.kernel.org; linux-kernel@vger.kernel.org; > mturque...@baylibre.com; s.ha...@pengutronix.de; shawn...@kernel.org; > Anson Huang <anson.hu...@nxp.com>; Fabio Estevam > <fabio.este...@nxp.com>; Jerome Forissier <jerome.foriss...@linaro.org>; > Peng Fan <peng....@nxp.com>; Rob Herring <r...@kernel.org> > Cc: dl-linux-imx <linux-...@nxp.com> > Subject: Re: [PATCH 2/2] clk: imx: imx7d: remove clks_init_on array > > 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: 2018年8月8日 12:39 > > >>>>> To: shawn...@kernel.org; s.ha...@pengutronix.de; > > >>>>> ker...@pengutronix.de; Fabio Estevam <fabio.este...@nxp.com>; > > >>>>> mturque...@baylibre.com; sb...@kernel.org; > > >>>>> linux-arm-ker...@lists.infradead.org; > > >>>>> linux-...@vger.kernel.org; linux-kernel@vger.kernel.org > > >>>>> Cc: dl-linux-imx <linux-...@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? > > > > Sounds reasonable, but how could this be done without introducing > > platform-specific stuff in the OP-TEE driver? > > > > Why is that a goal? I do NOT think we should consider such case in this patch series, whatever OP-TEE needs for its own feature, it should do necessary operations either in its driver or somewhere else by adding new patch. Anson.
