Hi, Stephen Anson Huang Best Regards!
> -----Original Message----- > From: Stephen Boyd <sb...@kernel.org> > Sent: Friday, August 31, 2018 9:29 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>; 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 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? Yes, I agree with you, OP-TEE should maintain its clocks when OP-TEE is enabled. This is ONLY a concern raised by Peng, all platforms' current clock driver does NOT consider this case, so I think this patch should be fine for now? Thanks. Anson.
