linux-kernel - Re: [PATCH 3/6] drivers/thermal/exynos: check IS

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Message-ID: <CAPLW+4nVY4sJtFp56A271pEqd0n1ZuQKY0JeUbPcWDW6FNY7fg@mail.gmail.com>
Date: Tue, 23 Jul 2024 09:51:51 -0500
From: Sam Protsenko <semen.protsenko@...aro.org>
To: Mateusz Majewski <m.majewski2@...sung.com>
Cc: linux-pm@...r.kernel.org, linux-samsung-soc@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, Bartlomiej Zolnierkiewicz <bzolnier@...il.com>, 
	Krzysztof Kozlowski <krzk@...nel.org>, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Daniel Lezcano <daniel.lezcano@...aro.org>, Zhang Rui <rui.zhang@...el.com>, 
	Lukasz Luba <lukasz.luba@....com>, Rob Herring <robh@...nel.org>, 
	Conor Dooley <conor+dt@...nel.org>, Alim Akhtar <alim.akhtar@...sung.com>
Subject: Re: [PATCH 3/6] drivers/thermal/exynos: check IS_ERR(data->clk) consistently

On Tue, Jul 23, 2024 at 9:17 AM Mateusz Majewski
<m.majewski2@...sung.com> wrote:
>
> > Also, if it's only optional for Exynos850 (and not optional for other
> > chips), maybe it would be a good idea to use *_optional_* API only for
> > Exynos850 case, so that the driver's behavior for those chips stays
> > unchanged.
>
> Probably should just set the clock to NULL in case of 850 then?
>

Ah, you are right, there is not much sense in doing both. I guess the
canonical way to do that (please check the drivers I referenced) -- is
not to check the chip, but just run devm_clk_get_optional(), which
sets the clock to NULL in case it's missing in dts. Less code this
way. And while at it, maybe consider reducing the code even more by
using devm_clk_get_optional_prepared().

> > Btw, from the downstream kernel code [1] I can see that the only TMU
> > clock present in Exynos850 is
> > GOUT_BLK_PERI_UID_BUSIF_TMU_IPCLKPORT_PCLK (which I was able to
> > confirm in TRM). But it's not enabled in clk-exynos850.c driver right
> > now. Do you want me by chance to send the patch adding it?
>
> Would be very grateful :) If nothing else, it would be useful for
> testing.

Cool, will try to do that soon!