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 X-Spam-Level: X-Spam-Status: No, score=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EAE78C433EF for ; Wed, 15 Sep 2021 14:46:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CFDE761209 for ; Wed, 15 Sep 2021 14:46:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237955AbhIOOr3 (ORCPT ); Wed, 15 Sep 2021 10:47:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:45358 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230499AbhIOOr1 (ORCPT ); Wed, 15 Sep 2021 10:47:27 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D22EC60E90; Wed, 15 Sep 2021 14:46:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631717168; bh=1r+zXP5h+3hNBMoJbh26kMNfLM1fbaF7tV2heVrir+M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sEqioIZuvY92a5wYiMJqFTgUn3qZlSCQt9oQLjdp/BtxZj9djTpXHSRX2fs/dDpDc k5wUYg153aED2O/rZbN9R6fKFvpidfx94VNtUsH+F6Pv01JnPvoYPAjsvwKqb5X5L+ YzDVKU5W9rZ0bPdLZjk3Xtz65bSfJOFJoeabYs3Y= Date: Wed, 15 Sep 2021 16:46:06 +0200 From: Greg KH To: Min Li Cc: "derek.kiernan@xilinx.com" , "dragan.cvetic@xilinx.com" , "arnd@arndb.de" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH misc] misc: Add Renesas Synchronization Management Unit (SMU) support Message-ID: References: <1630608353-7606-1-git-send-email-min.li.xe@renesas.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 15, 2021 at 02:42:55PM +0000, Min Li wrote: > > > > > +/* > > > > > + * RSMU IOCTL List > > > > > + */ > > > > > +#define RSMU_MAGIC '?' > > > > > > > > Where did you get this value from? > > > > > > > > Where did you reserve it? > > > > > > No I didn't reserve it. I checked other code and they all seem to use > > > a random character > > > > That's not the best way to do this. > > > > Why do you need ioctls at all anyway? What userspace tools will be > > accessing this driver? Do you have a link to where they are located at? > > Hi Greg > > The userspace tool is called PCM4L (PTP Clock Manager for Linux) from Renesas > > https://www.renesas.com/us/en/software-tool/ptp-clock-manager-linux > > But the functions of this misc driver is not ptp related. It is meant for being called by pcm4l to > support GNSS assisted partial timing support (APTS), which doesn't have abstracted/dedicated > Linux Kernel API's. That is why I went for IOCTL in the first place. Why not work on a real set of apis for this type of thing so that all devices of this type will work properly? thanks, greg k-h