From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
Stephen Boyd <sboyd@kernel.org>
Cc: Guenter Roeck <linux@roeck-us.net>,
mturquette@baylibre.com, linux-clk@vger.kernel.org,
Neil Armstrong <narmstrong@baylibre.com>,
jbrunet@baylibre.com, khilman@baylibre.com,
linux-kernel@vger.kernel.org, linux-amlogic@lists.infradead.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 2/3] clk: divider: Switch from .round_rate to .determine_rate by default
Date: Fri, 2 Jul 2021 14:46:11 +0200 [thread overview]
Message-ID: <e21c34a3-2586-057d-013b-6c8ec094d1a8@samsung.com> (raw)
In-Reply-To: <CAFBinCAASQUB=cg5EFsBQ4jd3TvcCJzV1=sYJci4ibR7FjRcww@mail.gmail.com>
Hi
On 02.07.2021 11:19, Martin Blumenstingl wrote:
> Hi Stephen,
>
> On Fri, Jul 2, 2021 at 3:02 AM Stephen Boyd <sboyd@kernel.org> wrote:
> [...]
>> My guess is that we have drivers copying the clk_ops from the
>> divider_ops structure and so they are copying over round_rate but not
>> determine_rate.
> I just learned something new - thanks for investigating this as well!
>
> $ git grep "clk_divider_ops\.round_rate" drivers/
> drivers/clk/bcm/clk-bcm2835.c: return clk_divider_ops.round_rate(hw,
> rate, parent_rate);
I confirm that this issue appears also on Raspberry Pi 3b+ board. I was
about to write a bug report, but you were faster. The funny thing is
that is so nondeterministic, that automated bisecting failed to catch it.
> drivers/clk/clk-stm32f4.c: return clk_divider_ops.round_rate(hw,
> rate, prate);
> drivers/clk/clk-stm32h7.c: return clk_divider_ops.round_rate(hw,
> rate, prate);
> drivers/clk/clk-stm32mp1.c: req->rate =
> clk_divider_ops.round_rate(hw, req->rate, &best_parent_rate);
> drivers/clk/imx/clk-divider-gate.c: return
> clk_divider_ops.round_rate(hw, rate, prate);
> $ git grep "clk_divider_ro_ops\.round_rate" drivers/
> $
>
> Changing these over to use clk_divider_ops.determine_rate doesn't seem too hard.
> The part that I am not sure about is how to organize the patches.
> 1) amend the changes to all relevant drivers (from above) to this patch
> 2) multiple patches:
> - adding .determine_rate to the default divider ops (but not removing
> .round_rate)
> - a single patch for each relevant driver (from above)
> - removing .round_rate from the default divider ops
>
> Another approach is to first create clk_divider_determine_rate() (as
> done here) and export it.
> Then I could have one individual patch for each relevant driver (from
> above) to use:
> .determine_rate = clk_divider_determine_rate,
> Then finally I could remove clk_divider_round_rate() and switch over
> the default divider ops to .determine_rate as well.
>
> Which way do you prefer?
>
>
> Best regards,
> Martin
>
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
next prev parent reply other threads:[~2021-07-02 12:46 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-27 22:39 [PATCH v3 0/3] clk: meson: rounding for fast clocks on 32-bit SoCs Martin Blumenstingl
2021-06-27 22:39 ` [PATCH v3 1/3] clk: divider: Add re-usable determine_rate implementations Martin Blumenstingl
2021-06-30 18:39 ` Stephen Boyd
2021-06-27 22:39 ` [PATCH v3 2/3] clk: divider: Switch from .round_rate to .determine_rate by default Martin Blumenstingl
2021-06-30 18:39 ` Stephen Boyd
2021-07-01 20:25 ` Guenter Roeck
2021-07-01 20:57 ` Martin Blumenstingl
2021-07-01 21:43 ` Guenter Roeck
2021-07-02 0:53 ` Stephen Boyd
2021-07-02 1:02 ` Stephen Boyd
2021-07-02 9:19 ` Martin Blumenstingl
[not found] ` <CGME20210702124612eucas1p1762911deb37e4fb03adc9239bb715135@eucas1p1.samsung.com>
2021-07-02 12:46 ` Marek Szyprowski [this message]
2021-07-02 21:00 ` Stephen Boyd
2021-07-02 20:59 ` Stephen Boyd
2021-07-02 22:57 ` Martin Blumenstingl
2021-07-02 1:04 ` Stephen Boyd
2021-06-27 22:39 ` [PATCH v3 3/3] clk: meson: regmap: switch to determine_rate for the dividers Martin Blumenstingl
2021-06-30 18:39 ` Stephen Boyd
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