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From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Leo Yan <leo.yan@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@linaro.org>,
	James Clark <james.clark@linaro.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 6/9] coresight: Avoid enable programming clock duplicately
Date: Tue, 24 Jun 2025 10:13:26 +0530	[thread overview]
Message-ID: <291dae35-af69-4fa5-abca-f0a36e1c47d2@arm.com> (raw)
In-Reply-To: <20250610120351.GQ8020@e132581.arm.com>



On 10/06/25 5:33 PM, Leo Yan wrote:
> On Tue, Jun 10, 2025 at 04:09:32PM +0530, Anshuman Khandual wrote:
>>
>>
>> On 09/06/25 10:44 PM, Leo Yan wrote:
>>> 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.
>>
>> Just exit early for AMBA devices when 'pclk' clock is still NULL ?
>>
>> 	if (dev_is_amba(dev))
>> 		return pclk;
> 
> If it is an AMBA device, we should return a NULL pointer, as this
> indicates that the APB clock is not managed by the CoreSight driver.
> 
> In this patch, I did not perform any refactoring and simply made a
> straightforward changed.  The refactoring is done in the patch 07, as
> you suggested, where the function is refined as:
> 
>     if (dev_is_amba(dev)) {
>         return NULL;
>     } else {
>         pclk = devm_clk_get_enabled(dev, "apb_pclk");
>         ...
>     }
> 
> Would it be acceptable to keep this patch as it is?

Agreed. Let's avoid the churn here as the refactoring happens
later anyway.


  reply	other threads:[~2025-06-24  4:43 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-09 16:00 [PATCH v3 0/9] coresight: Fix and improve clock usage Leo Yan
2025-06-09 16:00 ` [PATCH v3 1/9] coresight: tmc: Support atclk Leo Yan
2025-06-09 16:00 ` [PATCH v3 2/9] coresight: catu: " Leo Yan
2025-06-09 16:00 ` [PATCH v3 3/9] coresight: etm4x: " Leo Yan
2025-06-09 16:00 ` [PATCH v3 4/9] coresight: Appropriately disable programming clocks Leo Yan
2025-06-09 16:11   ` Suzuki K Poulose
2025-06-09 16:38     ` Leo Yan
2025-06-24  4:23       ` Anshuman Khandual
2025-06-24  4:37   ` Anshuman Khandual
2025-06-09 16:00 ` [PATCH v3 5/9] coresight: Appropriately disable trace bus clocks Leo Yan
2025-06-09 16:14   ` Suzuki K Poulose
2025-06-09 16:43     ` Leo Yan
2025-06-09 16:00 ` [PATCH v3 6/9] coresight: Avoid enable programming clock duplicately Leo Yan
2025-06-09 16:58   ` Suzuki K Poulose
2025-06-09 17:14     ` Leo Yan
2025-06-10 10:39       ` Anshuman Khandual
2025-06-10 12:03         ` Leo Yan
2025-06-24  4:43           ` Anshuman Khandual [this message]
2025-06-24  5:11   ` Anshuman Khandual
2025-06-09 16:00 ` [PATCH v3 7/9] coresight: Consolidate clock enabling Leo Yan
2025-06-24  5:44   ` Anshuman Khandual
2025-06-24 10:08     ` Leo Yan
2025-06-09 16:00 ` [PATCH v3 8/9] coresight: Make clock sequence consistent Leo Yan
2025-06-09 16:00 ` [PATCH v3 9/9] coresight: Refactor runtime PM Leo Yan
2025-06-10 10:07   ` Anshuman Khandual

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