From: Lee Jones <lee.jones@linaro.org>
To: Michael Turquette <mturquette@baylibre.com>
Cc: Maxime Coquelin <maxime.coquelin@st.com>,
linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
sboyd@codeaurora.org, maxime.ripard@free-electrons.com,
s.hauer@pengutronix.de, geert@linux-m68k.org
Subject: Re: [PATCH RFC RFT 3/3] clk: introduce CLK_ENABLE_HAND_OFF flag
Date: Tue, 11 Aug 2015 19:20:13 +0100 [thread overview]
Message-ID: <20150811182013.GS18282@x1> (raw)
In-Reply-To: <20150811170924.2416.97764@quantum>
On Tue, 11 Aug 2015, Michael Turquette wrote:
> Quoting Maxime Coquelin (2015-08-11 03:02:23)
> > Hi Mike,
> >
> > On 08/11/2015 10:43 AM, Lee Jones wrote:
> > > On Mon, 10 Aug 2015, Michael Turquette wrote:
> > >
> > >>
> > >>
> > >> ST's driver is an unfortunate case. All of the clock data was shoved
> > >> into DT before we had a clue that doing so is a terrible idea.
> >
> > I tend to agree, and wouldn't do it this way if we could rewrite the
> > history.
> > But now, we have to support it.
> >
> > How can we pass CLK_ENABLE_HAND_OFF flag to a specific clock on STi
> > platform?
> >
> > Could we imagine having a kind of "clocks-enable-hand-off" property we
> > could use in our clock controller DT node?
>
> Maxime,
>
> Yes. I'm sure that the ST binding isn't the only one that needs
> something like this. Furthermore I am sure that there are interesting
> users like the FPGA people that would love to dynamically set this flag
> from DT based on their hardware description.
>
> So the question is, what does it look like? We've already discussed
> doing a clk-conf.c approach, but that is really meant for consumers of a
> clock to set their default parameters. I don't think that is the right
> way here.
>
> Probably we should list the hand-off clocks directly in the
> clock-provider node itself. We can design it as a list (for
> clock-controller nodes that expose multiple clocks). In practice for the
> st,flexgen binding it will always be a list with one element in it.
>
> In my email to Lee a few minutes ago I asked if ST actually needs to
> turn on gated clocks, or if the goal is to prevent already-on clocks
> (enabled by default out of reset, or bootloader) from being gated? I
> guess that the goal is the latter since we've been discussing "critical"
> clocks that will crash the system if disabled.
The latter is correct. Clocks are on at boot-up.
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
next prev parent reply other threads:[~2015-08-11 18:20 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-07 19:09 [PATCH RFC RFT 0/3] clk: detect per-user enable imbalances and implement hand-off Michael Turquette
2015-08-07 19:09 ` [PATCH RFC RFT 1/3] clk: per-user clk prepare & enable ref counts Michael Turquette
2015-08-10 13:47 ` Maxime Coquelin
2015-08-10 19:31 ` Michael Turquette
2015-08-07 19:09 ` [PATCH RFC RFT 2/3] clk: clk_put WARNs if user has not disabled clk Michael Turquette
2015-09-30 15:38 ` Geert Uytterhoeven
[not found] ` <20151020124000.20687.60752@quantum>
2015-10-20 12:52 ` Russell King - ARM Linux
2015-10-21 9:50 ` Geert Uytterhoeven
2015-10-21 10:59 ` Russell King - ARM Linux
2015-10-21 15:50 ` Michael Turquette
2015-10-21 16:46 ` Geert Uytterhoeven
2015-08-07 19:09 ` [PATCH RFC RFT 3/3] clk: introduce CLK_ENABLE_HAND_OFF flag Michael Turquette
2015-08-10 14:48 ` Lee Jones
[not found] ` <20150810185516.2416.32293@quantum>
2015-08-11 8:43 ` Lee Jones
2015-08-11 10:02 ` Maxime Coquelin
2015-08-11 10:11 ` Geert Uytterhoeven
2015-08-11 11:36 ` Maxime Coquelin
2015-08-11 11:41 ` Maxime Coquelin
2015-08-11 11:49 ` Geert Uytterhoeven
2015-08-11 12:03 ` Maxime Coquelin
2015-08-11 12:34 ` Geert Uytterhoeven
2015-08-11 12:03 ` Lee Jones
2015-08-11 17:09 ` Michael Turquette
2015-08-11 18:17 ` Lee Jones
2015-08-12 7:27 ` Geert Uytterhoeven
2015-08-12 7:51 ` Lee Jones
2015-08-11 17:09 ` Michael Turquette
2015-08-11 18:20 ` Lee Jones [this message]
[not found] ` <20150811170904.2416.43354@quantum>
2015-08-11 18:33 ` Lee Jones
[not found] ` <20150811185827.31346.68194@quantum>
2015-08-18 15:52 ` Maxime Ripard
[not found] ` <20150818163356.31346.15075@quantum>
2015-08-20 15:11 ` Maxime Ripard
2015-08-18 15:58 ` Maxime Ripard
[not found] ` <20150818163931.31346.78267@quantum>
2015-08-20 15:39 ` Maxime Ripard
2015-08-10 15:36 ` [PATCH RFC RFT 0/3] clk: detect per-user enable imbalances and implement hand-off Lee Jones
[not found] ` <20150810192810.2416.25672@quantum>
2015-08-11 9:11 ` Lee Jones
2015-08-11 9:20 ` Geert Uytterhoeven
[not found] ` <20150811164151.2416.33353@quantum>
2015-08-11 17:42 ` Geert Uytterhoeven
2015-08-18 15:45 ` Maxime Ripard
[not found] ` <20150818164356.31346.80341@quantum>
2015-08-20 15:15 ` Maxime Ripard
[not found] ` <20150825215051.31346.56261@quantum>
2015-08-26 6:54 ` Lee Jones
2015-08-26 8:42 ` Maxime Coquelin
2015-08-26 9:09 ` Lee Jones
2015-08-26 9:37 ` Maxime Coquelin
2015-08-26 20:41 ` Lee Jones
2015-08-29 3:49 ` Maxime Ripard
2015-08-29 3:55 ` Maxime Ripard
[not found] ` <20150930123649.3201.75689@quantum>
2015-10-01 19:56 ` Maxime Ripard
2015-11-24 9:48 ` Heiko Stübner
2015-12-05 0:46 ` Michael Turquette
2016-02-11 21:33 ` Michael Turquette
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