From: Rob Herring <robherring2@gmail.com>
To: Lee Jones <lee.jones@linaro.org>
Cc: "linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Mike Turquette <mturquette@linaro.org>,
kernel@stlinux.com, Stephen Boyd <sboyd@codeaurora.org>,
Geert Uytterhoeven <geert@linux-m68k.org>
Subject: Re: [PATCH v6 4/4] clk: dt: Introduce binding for always-on clock support
Date: Tue, 7 Apr 2015 15:32:02 -0500 [thread overview]
Message-ID: <CAL_JsqJW7O=p3dUCw6A+J_x=PtHa6=GuS87hZORBermkDWDKLA@mail.gmail.com> (raw)
In-Reply-To: <1428432239-4114-5-git-send-email-lee.jones@linaro.org>
On Tue, Apr 7, 2015 at 1:43 PM, Lee Jones <lee.jones@linaro.org> wrote:
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Please use get_maintainers.pl in the future.
Acked-by: Rob Herring <robh@kernel.org>
> ---
> .../devicetree/bindings/clock/clock-bindings.txt | 38 ++++++++++++++++++++++
> 1 file changed, 38 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/clock/clock-bindings.txt b/Documentation/devicetree/bindings/clock/clock-bindings.txt
> index 06fc6d5..daf3323 100644
> --- a/Documentation/devicetree/bindings/clock/clock-bindings.txt
> +++ b/Documentation/devicetree/bindings/clock/clock-bindings.txt
> @@ -44,6 +44,44 @@ For example:
> clocks by index. The names should reflect the clock output signal
> names for the device.
>
> +clock-always-on: Some hardware contains bunches of clocks which must never be
> + turned off. If drivers a) fail to obtain a reference to any
> + of these or b) give up a previously obtained reference
> + during suspend, the common clk framework will attempt to
> + disable them and a platform can fail irrecoverably as a
> + result. Usually the only way to recover from these failures
> + is to reboot.
> +
> + To avoid either of these two scenarios from catastrophically
> + disabling an otherwise perfectly healthy running system,
> + clocks can be identified as always-on using this property
> + from inside a clocksource's node.
> +
> + This property is not to be abused. It is only to be used to
> + protect platforms from being crippled by gated clocks, not
> + as a convenience function to avoid using the framework
> + correctly inside device drivers.
> +
> + Expected values are hardware clock indices. If the
> + clock-indices property (see below) is used, then supplied
> + values must correspond to one of the listed identifiers.
> + Using the clock-indices example below, hardware clock <2>
> + is missing, therefore it is considered invalid to then
> + list clock <2> as an always-on clock.
> +
> +For example:
> +
> + oscillator {
> + #clock-cells = <1>;
> + clock-output-names = "ckil", "ckih";
> + clock-always-on = <0>, <1>;
> + };
> +
> +- this node defines a device with two clock outputs, just as in the
> + example above. The only difference being that 'ckil' and 'ckih'
> + are now identified as an always-on clocks, so the framework will
> + know to never attempt to gate them.
> +
> clock-indices: If the identifying number for the clocks in the node
> is not linear from zero, then this allows the mapping of
> identifiers into the clock-output-names array.
> --
> 1.9.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2015-04-07 20:32 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-07 18:43 [PATCH v6 0/4] clk: Provide support for always-on clocks Lee Jones
2015-04-07 18:43 ` [PATCH v6 1/4] ARM: sti: stih407-family: Supply defines for CLOCKGEN A0 Lee Jones
2015-04-07 18:43 ` [PATCH v6 2/4] ARM: sti: stih410-clocks: Identify critical clocks as always-on Lee Jones
2015-04-07 18:43 ` [PATCH v6 3/4] clk: Provide always-on clock support Lee Jones
2015-04-08 5:02 ` Stephen Boyd
2015-04-07 18:43 ` [PATCH v6 4/4] clk: dt: Introduce binding for " Lee Jones
2015-04-07 19:17 ` Maxime Ripard
2015-04-08 8:14 ` Lee Jones
2015-04-08 9:43 ` Maxime Ripard
2015-04-08 10:38 ` Lee Jones
2015-04-08 15:57 ` Maxime Ripard
2015-04-08 17:23 ` Lee Jones
2015-04-22 9:34 ` Maxime Ripard
2015-04-29 14:17 ` Lee Jones
2015-04-29 14:33 ` Geert Uytterhoeven
2015-04-29 15:11 ` Lee Jones
2015-04-29 20:27 ` Maxime Ripard
2015-04-29 14:51 ` Sascha Hauer
2015-04-29 16:07 ` Lee Jones
2015-04-29 23:05 ` Michael Turquette
2015-05-04 13:31 ` Maxime Ripard
2015-04-29 20:23 ` Maxime Ripard
2015-04-30 9:57 ` Lee Jones
2015-05-01 5:34 ` Sascha Hauer
2015-05-01 6:44 ` Lee Jones
2015-05-07 21:20 ` Maxime Ripard
2015-05-08 7:22 ` Lee Jones
2015-05-15 14:12 ` Maxime Ripard
2015-04-07 20:32 ` Rob Herring [this message]
2015-04-08 5:25 ` Stephen Boyd
2015-04-08 5:28 ` [PATCH v6 0/4] clk: Provide support for always-on clocks Stephen Boyd
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