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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 DA182C4742C for ; Wed, 4 Nov 2020 02:42:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A849822464 for ; Wed, 4 Nov 2020 02:42:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730678AbgKDCm0 (ORCPT ); Tue, 3 Nov 2020 21:42:26 -0500 Received: from vps0.lunn.ch ([185.16.172.187]:33914 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730153AbgKDCm0 (ORCPT ); Tue, 3 Nov 2020 21:42:26 -0500 Received: from andrew by vps0.lunn.ch with local (Exim 4.94) (envelope-from ) id 1ka8kV-0058ru-C2; Wed, 04 Nov 2020 03:42:11 +0100 Date: Wed, 4 Nov 2020 03:42:11 +0100 From: Andrew Lunn To: =?utf-8?Q?=C5=81ukasz?= Stelmach Cc: jim.cromie@gmail.com, Heiner Kallweit , "David S. Miller" , Jakub Kicinski , Rob Herring , Kukjin Kim , Krzysztof Kozlowski , Russell King , netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, Marek Szyprowski , =?utf-8?Q?Bart=C5=82omiej_=C5=BBolnierkiewicz?= Subject: Re: [PATCH v5 3/5] net: ax88796c: ASIX AX88796C SPI Ethernet Adapter Driver Message-ID: <20201104024211.GS933237@lunn.ch> References: <20201103151536.26472-1-l.stelmach@samsung.com> <20201103151536.26472-4-l.stelmach@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201103151536.26472-4-l.stelmach@samsung.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > +config SPI_AX88796C_COMPRESSION > + bool "SPI transfer compression" > + default n > + depends on SPI_AX88796C > + help > + Say Y here to enable SPI transfer compression. It saves up > + to 24 dummy cycles during each transfer which may noticably > + speed up short transfers. This sets the default value that is > + inherited by network interfecase during probe. It can be interface > + changed in run time via spi-compression ethtool tunable. changed _at_ run time... > +static int > +ax88796c_set_tunable(struct net_device *ndev, const struct ethtool_tunable *tuna, > + const void *data) > +{ > + struct ax88796c_device *ax_local = to_ax88796c_device(ndev); > + > + switch (tuna->id) { > + case ETHTOOL_SPI_COMPRESSION: > + if (netif_running(ndev)) > + return -EBUSY; > + ax_local->capabilities &= ~AX_CAP_COMP; > + ax_local->capabilities |= *(u32 *)data ? AX_CAP_COMP : 0; You should probably validate here that data is 0 or 1. That is what ax88796c_get_tunable() will return. It seems like this controls two hardware bits: SPICR_RCEN | SPICR_QCEN Maybe at some point it would make sense to allow these bits to be set individually? If you never validate the tunable, you cannot make use of other values to control the bits individually. Andrew