From: Jassi Brar <jassisinghbrar@gmail.com>
To: Lee Jones <lee.jones@linaro.org>
Cc: Jassi Brar <jaswinder.singh@linaro.org>,
Devicetree List <devicetree@vger.kernel.org>,
Mike Turquette <mturquette@linaro.org>,
kernel@stlinux.com, Stephen Boyd <sboyd@codeaurora.org>,
lkml <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 3/4] clk: Provide always-on clock support
Date: Mon, 2 Mar 2015 15:38:12 +0530 [thread overview]
Message-ID: <CABb+yY07woiiG8e2kff_AsiFCHNP+TKYyNm_o6=f5WmFsLi8gQ@mail.gmail.com> (raw)
In-Reply-To: <20150302083652.GE31325@x1>
On Mon, Mar 2, 2015 at 2:06 PM, Lee Jones <lee.jones@linaro.org> wrote:
> On Sat, 28 Feb 2015, Jassi Brar wrote:
>
>> On 28 February 2015 at 02:44, Lee Jones <lee.jones@linaro.org> 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
>
Thanks, I wasn't aware of the history.
>> 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?
>
The phantom user - that's there but none can see it.
How about?
+ of_property_for_each_string(np, "clock-always-on", prop, clkname) {
+ clk = __clk_lookup(clkname);
+ if (!clk)
+ continue;
+
+ clk->core->enable_count = 1;
+ clk->core->prepare_count = 1;
+ }
-jassi
next prev parent reply other threads:[~2015-03-02 10:08 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-27 21:14 [PATCH 0/4] clk: Provide support for always-on clocks Lee Jones
2015-02-27 21:14 ` [PATCH 1/4] ARM: sti: stih407-family: Supply defines for CLOCKGEN A0 Lee Jones
2015-02-27 21:14 ` [PATCH 2/4] ARM: sti: stih410-clocks: Identify critical clocks as always-on Lee Jones
2015-04-02 8:00 ` [STLinux Kernel] " Peter Griffin
2015-02-27 21:14 ` [PATCH 3/4] clk: Provide always-on clock support Lee Jones
2015-02-27 21:51 ` Lee Jones
2015-02-28 7:52 ` [STLinux Kernel] " Maxime Coquelin
2015-03-02 8:16 ` Lee Jones
2015-04-01 1:13 ` Michael Turquette
2015-02-28 9:21 ` Jassi Brar
2015-03-02 8:36 ` Lee Jones
2015-03-02 10:08 ` Jassi Brar [this message]
2015-03-02 10:18 ` Lee Jones
2015-03-02 10:25 ` [STLinux Kernel] " Maxime Coquelin
2015-03-02 10:32 ` Lee Jones
2015-03-02 10:28 ` Jassi Brar
2015-03-02 10:40 ` Lee Jones
2015-04-01 1:42 ` Michael Turquette
2015-04-02 4:39 ` Jassi Brar
2015-04-02 7:10 ` Lee Jones
2015-02-27 21:14 ` [PATCH 4/4] clk: dt: Introduce binding for " Lee Jones
2015-04-02 8:12 ` [STLinux Kernel] [PATCH 0/4] clk: Provide support for always-on clocks Peter Griffin
2015-04-02 9:45 ` Gabriel Fernandez
2015-04-02 10:53 ` Lee Jones
2015-04-02 10:58 ` Lee Jones
2015-04-02 10:52 ` Lee Jones
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CABb+yY07woiiG8e2kff_AsiFCHNP+TKYyNm_o6=f5WmFsLi8gQ@mail.gmail.com' \
--to=jassisinghbrar@gmail.com \
--cc=devicetree@vger.kernel.org \
--cc=jaswinder.singh@linaro.org \
--cc=kernel@stlinux.com \
--cc=lee.jones@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mturquette@linaro.org \
--cc=sboyd@codeaurora.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).