From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-m49219.qiye.163.com (mail-m49219.qiye.163.com [45.254.49.219]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 035D5125D0; Fri, 13 Feb 2026 05:47:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.254.49.219 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770961626; cv=none; b=ZFjsPALmZPB04eV4FX5YbEZHIGOGEVYIQcaBAgolkQWIllFsNLtOsylQVL6FXdbVgOzofZYrYngyrLoODjgiWnWUwJeSc5iW4rudtS1Tz7AKkmF4xcLmxJsHvuavCJ7tUlOYXUNW0Pfh6V/WOp/TtrKOuALXsqqd5QfgaWkrRIQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770961626; c=relaxed/simple; bh=hNzL3N85QvOiW+c9omm66dO80JWlIxMuz+p+7XxE4+s=; h=Cc:Subject:To:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=g7acLDSBrQtg64xCCcYZjGam27gkIYCVNHOIGUYWGCXr4CPSXB0pAHLdwvnxJVV8tXIZOjM/+wdEipleeXzyGFPwt1rQu8qzIYN1joRzqSNFvo8yAaT6fOLFCs1MFqIpZVwwt30R6srIyroT1wKd5YYFO/z3VGXdu1sMmu1K2Tk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rock-chips.com; spf=pass smtp.mailfrom=rock-chips.com; dkim=pass (1024-bit key) header.d=rock-chips.com header.i=@rock-chips.com header.b=YGcEa/tk; arc=none smtp.client-ip=45.254.49.219 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rock-chips.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rock-chips.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=rock-chips.com header.i=@rock-chips.com header.b="YGcEa/tk" Received: from [172.16.12.14] (unknown [58.22.7.114]) by smtp.qiye.163.com (Hmail) with ESMTP id 340b1136a; Fri, 13 Feb 2026 11:24:31 +0800 (GMT+08:00) Cc: shawn.lin@rock-chips.com, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, hy50.seo@samsung.com, kwangwon.min@samsung.com Subject: Re: [PATCH v2 1/3] mmc: dw_mmc: Using devm_clk_get_optional() for biu_clk To: "ping.gao" , ulf.hansson@linaro.org, jh80.chung@samsung.com, sebastian.reichel@collabora.com References: <20260213030816.1134487-1-ping.gao@samsung.com> From: Shawn Lin Message-ID: <7f79270e-b053-ec8e-6461-2ecdb1aa817d@rock-chips.com> Date: Fri, 13 Feb 2026 11:24:30 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20260213030816.1134487-1-ping.gao@samsung.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-HM-Tid: 0a9c5507594609cckunm34cf784e25c4df X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFDSUNOT01LS0k3V1ktWUFJV1kPCRoVCBIfWUFZQxpKHlZJSxpPHk9PSkkaSkJWFRQJFh oXVRMBExYaEhckFA4PWVdZGBILWUFZTkNVSUlVTFVKSk9ZV1kWGg8SFR0UWUFZT0tIVUpLSU9PT0 hVSktLVUpCS0tZBg++ DKIM-Signature: a=rsa-sha256; b=YGcEa/tkkPgkGrKefZ5p3f9xy6NrI2MoX0blaTuKMWATJlbH1nv09s8ocrAPooGEGyB9jFWl1NsMIQ7fqpNNX2sydT7ywegNGCAOCTItKLH3JuxijLaOC0TnmfAkQ1U6/7OI6cgUJf0DQ/xnCvp8fi82wh9FclmD4QMjvHYNFlU=; s=default; c=relaxed/relaxed; d=rock-chips.com; v=1; bh=GI4yIxoY7P8JYNPcxJ7olIjAXntja93xXQVd7GMSOqo=; h=date:mime-version:subject:message-id:from; 在 2026/02/13 星期五 11:08, ping.gao 写道: > By using devm_clk_get_optional, if clk is optional for device and not define in dts > it will return NULL, then clk_prepare_enable/clk_disable_unprepare for biu_clk is safe to > bail out internally. > > before biu_clk in dwmmc driver devm_clk_get fail, but it's ERR_PTR, > not null,it will panic when call clk_prepare > log is below: > [7: binder:436_2: 4998] Unable to handle kernel paging request at virtual address fffffffffffffffe > [7: binder:436_2: 4998] Mem abort info: > [7: binder:436_2: 4998] ESR = 0x0000000096000005 > [7: binder:436_2: 4998] EC = 0x25: DABT (current EL), IL = 32 bits > [7: binder:436_2: 4998] SET = 0, FnV = 0 > [7: binder:436_2: 4998] EA = 0, S1PTW = 0 > [7: binder:436_2: 4998] FSC = 0x05: level 1 translation fault > ... > [7: binder:436_2: 4998] Call trace: > [7: binder:436_2: 4998] clk_prepare+0x10/0x24 > [7: binder:436_2: 4998] dw_mci_runtime_resume+0x50/0x2d8 [dw_mmc_samsung cd210e210975263404c28fc89778f369f8398f0c] > [7: binder:436_2: 4998] dw_mci_exynos_runtime_resume+0x18/0x58 [dw_mmc_exynos_samsung 2735a594c7c9c9e8c65b0b87523fbf70dcaabfff] > [7: binder:436_2: 4998] pm_generic_runtime_resume+0x40/0x58 > [7: binder:436_2: 4998] pm_runtime_force_resume+0x9c/0x134 > [7: binder:436_2: 4998] platform_pm_resume+0x40/0x8c > [7: binder:436_2: 4998] dpm_run_callback+0x64/0x230 > [7: binder:436_2: 4998] __device_resume+0x1d8/0x394 > [7: binder:436_2: 4998] dpm_resume+0x110/0x2b8 > [7: binder:436_2: 4998] dpm_resume_end+0x1c/0x38 > [7: binder:436_2: 4998] suspend_devices_and_enter+0x828/0xab0 > [7: binder:436_2: 4998] pm_suspend+0x334/0x618 > [7: binder:436_2: 4998] state_store+0x104/0x144 > [7: binder:436_2: 4998] kobj_attr_store+0x30/0x48 > [7: binder:436_2: 4998] sysfs_kf_write+0x54/0x6c > [7: binder:436_2: 4998] kernfs_fop_write_iter+0x104/0x1a8 > [7: binder:436_2: 4998] vfs_write+0x24c/0x2f4 > [7: binder:436_2: 4998] ksys_write+0x78/0xe8 > [7: binder:436_2: 4998] __arm64_sys_write+0x1c/0x2c > [7: binder:436_2: 4998] invoke_syscall+0x58/0x114 > [7: binder:436_2: 4998] el0_svc_common+0xac/0xe0 > [7: binder:436_2: 4998] do_el0_svc+0x1c/0x28 > [7: binder:436_2: 4998] el0_svc+0x38/0x68 > [7: binder:436_2: 4998] el0t_64_sync_handler+0x68/0xbc > [7: binder:436_2: 4998] el0t_64_sync+0x1a8/0x1ac > Acked-by: Shawn Lin > Signed-off-by: ping.gao > --- > drivers/mmc/host/dw_mmc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index c5db92bbb094..6bcc1e7233c0 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -3375,7 +3375,7 @@ int dw_mci_probe(struct dw_mci *host) > "platform data not available\n"); > } > > - host->biu_clk = devm_clk_get(host->dev, "biu"); > + host->biu_clk = devm_clk_get_optional(host->dev, "biu"); > if (IS_ERR(host->biu_clk)) { > dev_dbg(host->dev, "biu clock not available\n"); > ret = PTR_ERR(host->biu_clk); >