From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 19EA628641E; Sun, 9 Aug 2026 15:20:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786288808; cv=none; b=Gamc5J0Pm5IEFqKnZSkKIZkHa1oHXj5GUgimhcj9ZUBuiZSNI5uvCtepHu13RTNI7SBHT/hjkXIO3Lx5bbo0P0Ehh3tVp5xbYOHzTYnqabSAaUEwKjPZhHlhIDnNCGeTI6pn86NL65zKsqR9I4ay2hLZ39VmBpm5NAAlp5cNO0g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786288808; c=relaxed/simple; bh=1Y4+yN+7jjQeWokiWwENeIWiEk8ip3UAnTDcNk45//8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=uHvEBbOAg/2j3to2aqCSFMjRZceMfyJRAAQ5we3u5+Puv0E2NemL2vh1jK22soy4H2UFy/WFO3LtSA+mwBqUBW8bXLLy1LCH2wFTAkd1oTKFT65cWTjziZ5HK98oVr1fFudehAWsZwakCvUnL523+dnqDsiyp0KvlnzkKlAjg2o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=T5+PUNx1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="T5+PUNx1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1CF1E1F000E9; Sun, 9 Aug 2026 15:20:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786288806; bh=ARwVcPLvnx7EkBM0oPgr55fHOYd6QKrvM3EwPl17m8k=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=T5+PUNx1uB/QZ7ynQ1OX2My7q3Mg/COzWAg/qjZitiPRL4X48qX5QoB+r3v9On6KQ ryv5GhMQf0PwrX6i0Zv38z9DHFbHo3i4AjCn52JYnzfdLnMIKfrMZfsQmK42Veefuj bDiRNrUWylkAS11Af6u1eYsRLSEVfvP9kcMiS0C+Ho1nHP/gY+CaHBYMoJUPm72jxA N3ox/ksDvb8C4g+2Zeq8tHya2rOw0vQvzdhGPM/ybnV7nNRulePqLfw2+2EA6hjvzI yvCf685ZDeIftkztcUUZmg+Zt1iYMRsQ+pRM8DFm8XH4ibLSGa0akYRTaWvyuBygpu o9rOC9C5W+niA== Message-ID: <7a170485-b349-4502-adb1-3ce6217bc435@kernel.org> Date: Sun, 9 Aug 2026 17:20:01 +0200 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 2/3] reset: Add Apple SoC CIO reset driver To: Joshua Peisach Cc: asahi@lists.linux.dev, Philipp Zabel , Rob Herring , Conor Dooley , linux-arm-kernel@lists.infradead.org, Neal Gompa , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Janne Grunau , Krzysztof Kozlowski References: <20260809-b4-cio-reset-v1-0-4f33777d9b4b@kernel.org> <20260809-b4-cio-reset-v1-2-4f33777d9b4b@kernel.org> Content-Language: en-US From: Sven Peter In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 09.08.26 16:30, Joshua Peisach wrote: > On Sun Aug 9, 2026 at 8:16 AM EDT, Sven Peter wrote: >> Add a driver for the reset of the CIO (USB4/Thunderbolt) blocks on >> Apple Silicon SoCs which has to be deasserted before their >> co-processor can be booted. On t8103 each port comes with a dedicated >> register page while t600x uses a single register with one request bit >> per port shared by all ports of a die inside the PMGR MMIO region. >> >> Signed-off-by: Sven Peter >> --- >>  MAINTAINERS                     |   1 + >>  drivers/reset/Kconfig           |  10 +++ >>  drivers/reset/Makefile          |   1 + >>  drivers/reset/reset-apple-cio.c | 182 +++++++++++++++++++++++++++++++ >> +++++++++ >>  4 files changed, 194 insertions(+) > >> + >> +static int apple_cio_reset_probe(struct platform_device *pdev) >> +{ >> +    struct device *dev = &pdev->dev; >> +    struct apple_cio_reset *priv; >> +    int ret; >> + >> +    priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); >> +    if (!priv) >> +        return -ENOMEM; >> + >> +    priv->variant = of_device_get_match_data(dev); > > Might be a dumb question, but does priv->variant also need to be > checked? Because later priv->variant->pmgr_child is and I *think* > it could return NULL. > > (Or is this not necessary since in theory the device should only run > this if detected... so this should never be an issue?) You might be able to get this driver to probe without a device tree node by manually forcing it with sysfs but well... play stupid games, win stupid prizes. Adding the check is just two lines and doesn't hurt though. Best, Sven