From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 To: Geert Uytterhoeven , "Maxime Coquelin" From: Michael Turquette In-Reply-To: Cc: "Lee Jones" , "linux-kernel@vger.kernel.org" , linux-clk@vger.kernel.org, "Stephen Boyd" , "Maxime Ripard" , "Sascha Hauer" References: <1438974570-20812-1-git-send-email-mturquette@baylibre.com> <1438974570-20812-4-git-send-email-mturquette@baylibre.com> <20150810144811.GN3249@x1> <20150810185516.2416.32293@quantum> <20150811084329.GA13374@x1> <55C9C82F.6060401@st.com> Message-ID: <20150811170928.2416.70005@quantum> Subject: Re: [PATCH RFC RFT 3/3] clk: introduce CLK_ENABLE_HAND_OFF flag Date: Tue, 11 Aug 2015 10:09:28 -0700 List-ID: Quoting Geert Uytterhoeven (2015-08-11 03:11:05) > Hi Maxime, > = > On Tue, Aug 11, 2015 at 12:02 PM, Maxime Coquelin > wrote: > > How can we pass CLK_ENABLE_HAND_OFF flag to a specific clock on STi > > platform? > = > Add the flag to the relevant clocks in the C code, e.g. in > clk_register_flexgen(): > = > if (!strcmp(name, "clk-icn-cpu")) > init.flags |=3D CLK_ENABLE_HAND_OFF; > = > > Could we imagine having a kind of "clocks-enable-hand-off" property we = could > > use in our clock controller DT node? > = > You can imagine doing "flex_flags |=3D CLK_ENABLE_HAND_OFF" in > st_of_flexgen_setup(), depending on the presence of such a property. This is precisely what Lee is trying to avoid. The would constitute a hand-rolled, open-code, gather-and-mark exercise that drivers would have to re-invent each time. (rough paraphrase of what Lee said) I think that we can come up with a reasonable DT wrapper around the flag. I will be ecstatic if we can agree that the meaning of the flag can be tweaked just a bit to mean, "prevent this critical clock from being disabled, as it was enabled out of reset or by the bootloader, until a driver claims it and calls clk_prepare_enable". Then everyone should be happy. Regards, Mike > = > However, not disabling clocks is a software policy, not a hardware descri= ption, > so IMHO it doesn't belong in DT. > = > Gr{oetje,eeting}s, > = > Geert > = > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m6= 8k.org > = > In personal conversations with technical people, I call myself a hacker. = But > when I'm talking to journalists I just say "programmer" or something like= that. > -- Linus Torvalds > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/