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X-CSE-ConnectionGUID: xpv6oPNnT8umua0ip/BgGA== X-CSE-MsgGUID: UXdZw47/Qoy00L0v54c0Xw== X-IronPort-AV: E=McAfee;i="6800,10657,11924"; a="90833984" X-IronPort-AV: E=Sophos;i="6.27,139,1787036400"; d="scan'208";a="90833984" Received: from fmviesa006.fm.intel.com ([10.60.135.146]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Oct 2026 01:15:29 -0700 X-CSE-ConnectionGUID: CL6XgozSQiCcd/U3Xfp4Gg== X-CSE-MsgGUID: npL6c5ofQv6XSbpjyGehyA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,139,1787036400"; d="scan'208";a="275216433" Received: from mkosciow-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.245.100]) by fmviesa006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Oct 2026 01:15:26 -0700 Date: Sun, 4 Oct 2026 11:15:24 +0300 From: Andy Shevchenko To: Linus Walleij , Danilo Krummrich Cc: Kim Phillips , jiale yao <19888972804@163.com>, Mark Brown , linux-spi@vger.kernel.org, Biju Das , "linux-gpio@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: RE: Re:RE: [PATCH] pinctrl: mcp23s08: reject devices without match data Message-ID: References: <20260925133804.2231004-1-yaojiale02@163.com> <34472b57.1961.1a0dd3dff12.Coremail.19888972804@163.com> <1186ef64.63b1.1a0e6e70a59.Coremail.19888972804@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo +Cc: Danilo (as you were involved in cleaning this up in the past and being co-maintainer of driver core) On Sun, Oct 04, 2026 at 01:06:07AM +0200, Linus Walleij wrote: > On Fri, Oct 2, 2026 at 12:19 PM Andy Shevchenko > wrote: > > On Fri, Oct 02, 2026 at 11:52:41AM +0200, Linus Walleij wrote: > > > On Fri, Oct 2, 2026 at 8:59 AM Andy Shevchenko ... > > > The entire name of the thing feels like debugfs-footgun > > > territory for example. > > > > Yeah, I can't find neither a thing on LWN.net nor in the in-tree documentation. > > The only useful piece of information is (in kernel-doc of struct bus_type): > > > > driver_override > > Set to true if this bus supports the driver_override mechanism, which > > allows userspace to force a specific driver to bind to a device via a sysfs > > attribute. > > This whole thing is weird, but OK. > > Since we have a ton of drivers depending on match data we either > have to patch them all to bail out if match data is NULL (like this > patch does) or, which is equivalent, opt out of driver_override > that much is certain. > > What I don't get is what this is intended for. What is the use case? > The commit says this is for VFIO. Shouldn't it be opt-in and turned > on only for VFIO then? > > Kim Phillips is listed as contract for the platform bus driver_override > so let's ask! Kim: what is this for? > > All of the device tree drivers use the platform bus, what's yhe > Unique Selling Point of this for our devices? -- With Best Regards, Andy Shevchenko