From: Stephen Boyd <sboyd@kernel.org>
To: Marek Szyprowski <m.szyprowski@samsung.com>,
Sylwester Nawrocki <s.nawrocki@samsung.com>,
linux-clk@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org,
Sylwester Nawrocki <snawrocki@kernel.org>,
Chanwoo Choi <cw00.choi@samsung.com>,
Krzysztof Kozlowski <krzk@kernel.org>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Marian Mihailescu <mihailescu2m@gmail.com>
Subject: Re: [PATCH v2] clk: samsung: exynos5420: Keep top G3D clocks enabled
Date: Mon, 23 Dec 2019 23:53:06 -0800 [thread overview]
Message-ID: <20191224075307.6BBAA2071A@mail.kernel.org> (raw)
In-Reply-To: <f4f23b53-4eae-de3e-c8b2-099909522ce2@samsung.com>
Quoting Sylwester Nawrocki (2019-12-19 02:05:04)
> On 12/16/19 14:14, Marek Szyprowski wrote:
> > In Exynos542x/5800 SoCs, the G3D leaf clocks are located in the G3D power
> > domain. This is similar to the other hardware modules and their power
> > domains. However there is one thing specific to G3D clocks hierarchy.
> > Unlike other hardware modules, the G3D clocks hierarchy doesn't have any
> > gate clock between the TOP part of the hierarchy and the part located in
> > the power domain and some SoC internal busses are sourced directly from
> > the TOP muxes. The consequence of this design if the fact that the TOP
> > part of the hierarchy has to be enabled permanently to ensure proper
> > operation of the SoC power related components (G3D power domain and
> > Exynos Power Management Unit for system suspend/resume).
> >
> > This patch adds an explicit call to clk_prepare_enable() on the last MUX
> > in the TOP part of G3D clock hierarchy to keep it enabled permanently to
> > ensure that the internal busses get their clock regardless of the main
> > G3D clock enablement status.
>
> > ---
> > diff --git a/drivers/clk/samsung/clk-exynos5420.c b/drivers/clk/samsung/clk-exynos5420.c
> > index 3a991ca1ee36..c9e5a1fb6653 100644
> > --- a/drivers/clk/samsung/clk-exynos5420.c
> > +++ b/drivers/clk/samsung/clk-exynos5420.c
>
> > @@ -1646,6 +1647,13 @@ static void __init exynos5x_clk_init(struct device_node *np,
> > exynos5x_subcmus);
> > }
> >
> > + /*
> > + * Keep top part of G3D clock path enabled permanently to ensure
> > + * that the internal busses get their clock regardless of the
> > + * main G3D clock enablement status.
> > + */
> > + clk_prepare_enable(__clk_lookup("mout_sw_aclk_g3d"));
> > +
> > samsung_clk_of_add_provider(np, ctx);
> > }
>
> It's a bit unfortunate we don't store that clock in the driver internally,
> which would let us avoid the __clk_lookup() call. I can't come up with any
> simple alternative though so let's apply it for now.
Yes it would be better to not use __clk_lookup(). I'll apply it for now
but please avoid it somehow in a future patch.
next prev parent reply other threads:[~2019-12-24 7:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20191216131423eucas1p2162d6bf0a870357be9f0ab308641015b@eucas1p2.samsung.com>
2019-12-16 13:14 ` [PATCH v2] clk: samsung: exynos5420: Keep top G3D clocks enabled Marek Szyprowski
2019-12-18 9:44 ` Krzysztof Kozlowski
2019-12-19 2:26 ` Chanwoo Choi
2019-12-19 10:05 ` Sylwester Nawrocki
2019-12-24 7:53 ` Stephen Boyd [this message]
2019-12-24 7:53 ` Stephen Boyd
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=20191224075307.6BBAA2071A@mail.kernel.org \
--to=sboyd@kernel.org \
--cc=b.zolnierkie@samsung.com \
--cc=cw00.choi@samsung.com \
--cc=krzk@kernel.org \
--cc=linux-clk@vger.kernel.org \
--cc=linux-samsung-soc@vger.kernel.org \
--cc=m.szyprowski@samsung.com \
--cc=mihailescu2m@gmail.com \
--cc=s.nawrocki@samsung.com \
--cc=snawrocki@kernel.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).