linux-kernel - Re: [PATCH v3 5/9] coresight: Appropriately disable trace bus clocks

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Message-ID: <20250609164320.GM8020@e132581.arm.com>
Date: Mon, 9 Jun 2025 17:43:20 +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 v3 5/9] coresight: Appropriately disable trace bus clocks

On Mon, Jun 09, 2025 at 05:14:09PM +0100, Suzuki Kuruppassery Poulose wrote:
> On 09/06/2025 17:00, Leo Yan wrote:
> > Some CoreSight components have trace bus clocks 'atclk' and are enabled
> > using clk_prepare_enable().  These clocks are not disabled when modules
> > exit.
> > 
> > As atclk is optional, use devm_clk_get_optional_enabled() to manage it.
> > The benefit is the driver model layer can automatically disable and
> > release clocks.
> > 
> > Check the returned value with IS_ERR() to detect errors but leave the
> > NULL pointer case if the clock is not found.  And remove the error
> > handling codes which are no longer needed.
> > 
> > Fixes: d1839e687773 ("coresight: etm: retrieve and handle atclk")
> > Reviewed-by: Anshuman Khandual <anshuman.khandual@....com>
> > Signed-off-by: Leo Yan <leo.yan@....com>
> 
> Can we consolidate the ATCLK handling to the core coresight helper for
> APB clocks ?  It is an optional clock for all devices anyways ?

Yes. ATCLK is always optional.

Could you check the patch 07? It is exactly a consolidation to put ATCLK
and APB clocks into a central place.

Thanks,
Leo