From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E0FAA2C375E for ; Mon, 21 Jul 2025 11:40:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753098042; cv=none; b=uPaQKwWaDUzcEJD3V2AN8lnhmNWaRXsv2ZehsyZX5THvS0/5ce8cfM2Ee79buR9/yDO8SbDlfpywRWBv2yelj1Sn2mVfQFrpAh9PteoR0mTf7VLxZvfn4XS2NAlMcuVLjYKuR6lGZMrXCO63IzHad6YU5uqvqTqJVCAqkEmW3WI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753098042; c=relaxed/simple; bh=qelmWF1xTMaYUjMsXWHlO7TF7AQn04EJmRk+xOhjksM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=te3tfsV8chX5Q2MqKnyNdenQ52mYuoT66oOfNZaLBpq8fPP2H5V/DBZxEWSMu8wCO6VELx7Fzv+C6aRlEzRXTK3LVMoQku7kYvMLIygy4uoS1WtVZzqpLWYolsK4fDNWFDKRzALBEF4S89rL06RWLMbXvHg+R5GtJi4DPSST7Mw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6DD54153B; Mon, 21 Jul 2025 04:40:34 -0700 (PDT) Received: from [10.57.30.25] (unknown [10.57.30.25]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 265A13F6A8; Mon, 21 Jul 2025 04:40:39 -0700 (PDT) Message-ID: <607c03a2-267c-46e6-a7fa-e733c1970e60@arm.com> Date: Mon, 21 Jul 2025 12:40:38 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 04/10] coresight: Appropriately disable programming clocks Content-Language: en-GB To: Leo Yan Cc: Mike Leach , James Clark , Anshuman Khandual , Alexander Shishkin , Greg Kroah-Hartman , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20250627-arm_cs_fix_clock_v4-v4-0-0ce0009c38f8@arm.com> <20250627-arm_cs_fix_clock_v4-v4-4-0ce0009c38f8@arm.com> <5a5f1355-563d-498a-9dec-3479a257b3e6@arm.com> <20250721104834.GC3137075@e132581.arm.com> From: Suzuki K Poulose In-Reply-To: <20250721104834.GC3137075@e132581.arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 21/07/2025 11:48, Leo Yan wrote: > 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. This will break ACPI based systems, as we may not have a "pclk" described for them. We should be able to tolerate "no pclk" Suzuki > > Thanks, > Leo