From mboxrd@z Thu Jan 1 00:00:00 1970 From: lee.jones@linaro.org (Lee Jones) Date: Mon, 2 Mar 2015 08:36:52 +0000 Subject: [PATCH 3/4] clk: Provide always-on clock support In-Reply-To: References: <1425071674-16995-1-git-send-email-lee.jones@linaro.org> <1425071674-16995-4-git-send-email-lee.jones@linaro.org> Message-ID: <20150302083652.GE31325@x1> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Sat, 28 Feb 2015, Jassi Brar wrote: > On 28 February 2015 at 02:44, Lee Jones wrote: > > Lots of platforms contain clocks which if turned off would prove fatal. > > The only way to recover from these catastrophic failures is to restart > > the board(s). Now, when a clock is registered with the framework it is > > compared against a list of provided always-on clock names which must be > > kept ungated. If it matches, we enable the existing CLK_IGNORE_UNUSED > > flag, which will prevent the common clk framework from attempting to > > gate it during the clk_disable_unused() procedure. > > > If a clock is critical on a certain board, it could be got+enabled > during early boot so there is always a user. I tried this. There was push-back from the DT maintainers. http://lists.infradead.org/pipermail/linux-arm-kernel/2015-February/324417.html > To be able to do that from DT, maybe add a new, say, CLK_ALWAYS_ON > flag could be made to initialize the clock with one phantom user > already. Or just reuse the CLK_IGNORE_UNUSED? How is that different to what this set is doing? -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog