linux-kernel - Re: [PATCH v4 04/10] coresight: Appropriately disable programming clocks

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Message-ID: <20250721104834.GC3137075@e132581.arm.com>
Date: Mon, 21 Jul 2025 11:48:34 +0100
From: Leo Yan <leo.yan@....com>
To: Suzuki K Poulose <suzuki.poulose@....com>
Cc: Mike Leach <mike.leach@...aro.org>,
	James Clark <james.clark@...aro.org>,
	Anshuman Khandual <anshuman.khandual@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 04/10] coresight: Appropriately disable programming
 clocks

On Mon, Jul 21, 2025 at 10:15:22AM +0100, Suzuki Kuruppassery Poulose wrote:

[...]

> > diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> > index 4ac65c68bbf44b98db22c3dad2d83a224ce5278e..dd2b4cc7a2b70cf060a3207548fe80e3824c489f 100644
> > --- a/include/linux/coresight.h
> > +++ b/include/linux/coresight.h
> > @@ -480,26 +480,16 @@ static inline bool is_coresight_device(void __iomem *base)
> >    * Returns:
> >    *
> >    * clk   - Clock is found and enabled
> > - * NULL  - clock is not found
> 
> This is still valid, right ?

No. Since this patch uses devm_clk_get_enabled() to get a clock, if the
pclk is not found, it returns -ENOENT (see of_parse_clkspec()).

Only the optional clock APIs (e.g., devm_clk_get_optional_enabled())
return a NULL pointer instead of -ENOENT when the clock is not found.

Thanks,
Leo