linux-kernel - Re: [PATCH v3 6/9] coresight: Avoid enable programming clock duplicately

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Message-ID: <20250609171413.GO8020@e132581.arm.com>
Date: Mon, 9 Jun 2025 18:14:13 +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 6/9] coresight: Avoid enable programming clock
 duplicately

On Mon, Jun 09, 2025 at 05:58:34PM +0100, Suzuki Kuruppassery Poulose wrote:

[...]

> >   static inline struct clk *coresight_get_enable_apb_pclk(struct device *dev)
> >   {
> > -	struct clk *pclk;
> > +	struct clk *pclk = NULL;
> > -	pclk = devm_clk_get_enabled(dev, "apb_pclk");
> > -	if (IS_ERR(pclk))
> > -		pclk = devm_clk_get_enabled(dev, "apb");
> > +	if (!dev_is_amba(dev)) {
> > +		pclk = devm_clk_get_enabled(dev, "apb_pclk");
> > +		if (IS_ERR(pclk))
> > +			pclk = devm_clk_get_enabled(dev, "apb");
> 
> AMBA driver doesn't handle "apb" clock ? So we may need to retain that here
> ?

Here checks the condition "if (!dev_is_amba(dev))", it means the device
is not an AMBA device (e.g., a platform device), the APB clock is
enabled at here.

Otherwise, for a AMBA device, the AMBA bus layer will help to enable
APB clock.

> Otherwise looks good to me.
> 
> Suzuki
> > +	}
> >   	return pclk;
> >   }
> > 
>