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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 E57D8C433E0 for ; Wed, 27 Jan 2021 14:47:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A231B207C4 for ; Wed, 27 Jan 2021 14:47:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233527AbhA0Ork (ORCPT ); Wed, 27 Jan 2021 09:47:40 -0500 Received: from esa.microchip.iphmx.com ([68.232.153.233]:41909 "EHLO esa.microchip.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234240AbhA0Ora (ORCPT ); Wed, 27 Jan 2021 09:47:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1611758849; x=1643294849; h=message-id:subject:from:to:cc:date:in-reply-to: references:mime-version:content-transfer-encoding; bh=QkcXxzNQo+CiSnWQy/sM6qbG/bFI75MPmn6Y5uD/e/U=; b=2nndfOLDruO1REt1OcAyYiaKsJuDmJWglVmFnJVQHFmBCagi1eLZXRhM 2KrGbh0lVjyJB62UePfKQsO8yaaTJs5riI2R9Amr9ZRukQkDNZayMYzU/ 8SF8LQMp2n5ItszouIlsNBY9bMmw37cke536DjC0F/srqrx9+aeX99JKC aJApRPhammmAUaVV5GdTD/Tz1aiBPPkqqL5DovE+3MCV+WTgdWm7viPTo 6wdptYoGeHwDOwXDW4AbVb/YQJWshSebxKQLvOUx4zEkZpyOAxIvUMJXD jfnEg//Sx/IFzgMOegEFT3XR65wGULGYmtys3gcw+HsvH+TmiU30hif0i Q==; IronPort-SDR: BcHjX8y/GyigjTmuyfrgx7h2mSYwhbnbjyAFiq2Cjw1F3b6eOvdgio45CkffKkSfE6pXkIc7TK xnUaPiPICzjCCNCs90aYUg2/TDVxK07db/QPZzAhqj38kgIh0RJz1B54HJ4yNduvlXrdkVS57t kADhIFfF9lcPHipdiC1y4RPlTQjV4/+o25+MOv91zqj4oXVYFnEiIo/FyfabCDnGBc4bS0S2/L kHumMp3TltCOVXGKIFLK87KcOz+J+iwVS6FpPi4DaiA/MSkS6xEx+MSaS/kKVqVVWya2nkZUZZ Dpo= X-IronPort-AV: E=Sophos;i="5.79,379,1602572400"; d="scan'208";a="112700639" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa1.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 27 Jan 2021 07:45:48 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Wed, 27 Jan 2021 07:45:48 -0700 Received: from [10.205.21.32] (10.10.115.15) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server id 15.1.1979.3 via Frontend Transport; Wed, 27 Jan 2021 07:45:46 -0700 Message-ID: <6221107eae5e749bc7fd75e057209c92c9edd7df.camel@microchip.com> Subject: Re: [PATCH v12 2/4] phy: Add ethernet serdes configuration option From: Steen Hegelund To: Kishon Vijay Abraham I , Vinod Koul CC: Alexandre Belloni , Lars Povlsen , Bjarni Jonasson , Microchip UNG Driver List , , , Andrew Lunn Date: Wed, 27 Jan 2021 15:45:45 +0100 In-Reply-To: <70aa5716-bd14-0a0a-26bc-d3dfa23de47e@ti.com> References: <20210107091924.1569575-1-steen.hegelund@microchip.com> <20210107091924.1569575-3-steen.hegelund@microchip.com> <92a943cc-b332-4ac6-42a8-bb3cdae13bc0@ti.com> <70aa5716-bd14-0a0a-26bc-d3dfa23de47e@ti.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Kishon, On Wed, 2021-01-27 at 18:04 +0530, Kishon Vijay Abraham I wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > ... > > > > > > I'm not familiar with Ethernet. Are these generic media types? what > > > does > > > SR or DAC refer to? > > > > The SR stands for Short Reach and is a fiber type connection used by > > SFPs.  There also other "reach" variants. > > > > DAC stands for Direct Attach Copper and is a type of cable that plugs > > into an SFP cage and provides information back to the user via its > > EEPROM regarding supported speed and capabilities in general.  These > > typically supports speed of 5G or more. > > > > The SFP/Phylink is the "out-of-band" method that provides the type of > > connection: speed and media type that allows the client to adapt the > > SerDes configuration to the type of media selected by the user. > > > > > Are there other media types? What is the out-of-band > > > mechanism by which the controller gets the media type? Why was this > > > not > > > required for other existing Ethernet SERDES? > > > > This is probably a matter of the interface speed are now getting higher > > and the amount of configuration needed for the SerDes have increased, > > at the same time as this is not being a static setup, because the user > > an plug and unplug media to the SFP cage. > > > > > Are you aware of any other > > > vendors who might require this? > > > > I suspect that going forward it will become more widespread, at least > > we have more chips in the pipeline that need this SerDes for high speed > > connectivity. > > For this case I would recommend to add new API, something like > phy_set_media(). Configure() and Validate() is more for probing > something that is supported by SERDES and changing the parameters. But > in this case, I'd think the media type is determined by the cable that > is connected and cannot be changed. > > Thanks > Kishon I assume that you would like a separate interface for the speed information as well? Thanks for your comments. BR Steen