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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 9B6A8C43382 for ; Thu, 27 Sep 2018 22:47:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 48D0E21712 for ; Thu, 27 Sep 2018 22:47:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sirena.org.uk header.i=@sirena.org.uk header.b="Q4ti55WG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 48D0E21712 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728052AbeI1FIC (ORCPT ); Fri, 28 Sep 2018 01:08:02 -0400 Received: from heliosphere.sirena.org.uk ([172.104.155.198]:39852 "EHLO heliosphere.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725924AbeI1FIC (ORCPT ); Fri, 28 Sep 2018 01:08:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sirena.org.uk; s=20170815-heliosphere; h=In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=wi9yvqu9ios2Pd1r/A7+TrFX27UGn77WevMLeTs5PyE=; b=Q4ti55WGxEdCyK88+o30phQ/K EEnQCQUvgWEUkyETsskSAQ7cVTI+5ZFSZCWyvkkMOvcGfNso9xFfubHwYQReP1c44haCnxl5VTbdP tKd5CRcPC8O3JYmRGLcRtGnVcRpGVgsngdPiBkswsz26yH+sr1wEqldqH9AlMgCPiwxis=; Received: from [2001:470:1f1d:6b5:7e7a:91ff:fede:4a45] (helo=finisterre.ee.mobilebroadband) by heliosphere.sirena.org.uk with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1g5f48-0007V3-D5; Thu, 27 Sep 2018 22:47:24 +0000 Received: by finisterre.ee.mobilebroadband (Postfix, from userid 1000) id CCE5C440078; Thu, 27 Sep 2018 23:47:23 +0100 (BST) Date: Thu, 27 Sep 2018 23:47:23 +0100 From: Mark Brown To: =?utf-8?B?xJDhurduZyBUcuG6p24gSGnhur91?= Cc: robh@kernel.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] dt-bindings: spi: fsl-lpspi: Option to allow stalling Message-ID: <20180927224723.GF20825@sirena.org.uk> References: <20180925203701.13605-1-dangtranhieu2012@gmail.com> <20180925203701.13605-2-dangtranhieu2012@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="TUvp6TiFcfhGC84w" Content-Disposition: inline In-Reply-To: X-Cookie: Disc space -- the final frontier! User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --TUvp6TiFcfhGC84w Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Sep 26, 2018 at 09:37:39PM +0700, =C4=90=E1=BA=B7ng Tr=E1=BA=A7n Hi= =E1=BA=BFu wrote: > Default value of the register is to allow stalling (NOSTALL bit not > set) but the spi-fsl-lpspi driver defaults to setting the NOSTALL bit > in CFGR1. To me, it's more logical to leave the NOSTALL bit off with > fsl,nostall binding to set the bit but as I am not sure if there are > other drivers depending on the NOSTALL bit being set and not wanting > to break other drivers hence introduction of this binding to keep the > current default behavior. I can't see a situation where you'd actively want to report an error rather than stall, stalling allows us to handle things gracefully by restarting things. Even if it's a timeout situation it sounds like we can unblock by reading/writing the stalled FIFO, and normally you'd be resetting the entire IP anyway. I'd imagine the driver is this way either through an oversight or because there's some bug on some silicon which means that stalling breaks. Probably best to just always enable stalling unless I'm misreading things, if it is silicon bugs on some versions then either a whitelist or blacklist of SoCs to enable on (depending on how common the bug is) would be the way forwards - that way SoCs where it works get the benefit. --TUvp6TiFcfhGC84w Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAlutXfoACgkQJNaLcl1U h9ABMgf/czCL8Xz21qJvcfFwf1QCjMgUyRCWY9a16J/vrdk/aDgSAtCrloo/6M6e Q2hByQEEQzinBT10Y280ZFhpfdqOCLJcXVGtEC4QIXUdY0FeNRWFvNyh2ipJ0WB+ ovlbt0puUcGIX0BQHCW/k9Yd33r5fawXq9ZYmmota43b6JjT+83LIXD8YwF+3MFH RtRvcfN7hp09oQO1xiWsdbY8JTnvlnbV4Sriij8eMnlDBXfiAHEEcmZbeZ0kZ5M4 Y/x+x0A/RZgws5P2WKasI0DTbp3fJj72hdbStB7vfwXOcOmzAzGk6assdQNGgrKi OFk3SNnVV8OGl7rwuNvyZ74whmIJqw== =1ny+ -----END PGP SIGNATURE----- --TUvp6TiFcfhGC84w--