From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D1634C83F27 for ; Tue, 22 Jul 2025 14:02:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=5PF6ylaxf/gzcoLgi7RbR7JAegQRu4QI8hjuHXDHN8A=; b=luDDj1Xr+vPboGnDdLTHo12Ukx 9tg3vm0TghleL/Uzn21F+rc1dEgWrWIlww/5ePzOqNPJvLJ7ee2EzGMz01ieBsB6iQHfM/bEgXCUs AKFDtkQQSariK8xvSuhnfj989hgZMlQMSkqijJ1PxSBcl5vtNhXOoyhyxfk3KmAJXiRwub9F9AC3V vTsQmwJ5/C/bJsFTWZRpA9vnh4tvapf/K3/Nm+5nGPLsKW61QhFr5c+w/+JSqeLhqG2MdDsLqN9fW 46TKZAISroRow2MZiUFVTDFLrzAV0hGqPsB4KvOp1t8KFKh6SwGGmYS1hY517uAb7/5HBB+M/nFNz 7oNlNZXw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ueDZb-00000002d5R-1BnY; Tue, 22 Jul 2025 14:02:27 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ueCzm-00000002Xak-0of7 for linux-arm-kernel@lists.infradead.org; Tue, 22 Jul 2025 13:25:27 +0000 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 09304152B; Tue, 22 Jul 2025 06:25:20 -0700 (PDT) Received: from [10.1.36.73] (Suzukis-MBP.cambridge.arm.com [10.1.36.73]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 570583F6A8; Tue, 22 Jul 2025 06:25:24 -0700 (PDT) Message-ID: <8285b872-ecfa-42a6-9ead-e84ae409f79d@arm.com> Date: Tue, 22 Jul 2025 14:25:23 +0100 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> <607c03a2-267c-46e6-a7fa-e733c1970e60@arm.com> <20250721135958.GE3137075@e132581.arm.com> From: Suzuki K Poulose In-Reply-To: <20250721135958.GE3137075@e132581.arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250722_062526_278840_46282787 X-CRM114-Status: GOOD ( 15.41 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 21/07/2025 14:59, Leo Yan wrote: > On Mon, Jul 21, 2025 at 12:40:38PM +0100, Suzuki Kuruppassery Poulose wrote: >> 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" > > Get it. How about change the code like below? > > static inline struct clk *coresight_get_enable_apb_pclk(struct device *dev) > { > struct clk *pclk; > > pclk = devm_clk_get_enabled(dev, "apb_pclk"); > if (IS_ERR(pclk)) > pclk = devm_clk_get_enabled(dev, "apb"); > > /* Tolerate no pclk for ACPI device */ > if ((pclk == ERR_PTR(-ENOENT)) && has_acpi_companion(dev)) That might be OK, please could you test this out ? > return NULL; > > return pclk; > }