From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 901CA10E6 for ; Sat, 6 May 2023 01:15:16 +0000 (UTC) Received: from mx.dolansoft.org (s2.dolansoft.org [212.51.146.245]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 324DF2688 for ; Fri, 5 May 2023 18:15:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=brun.one; s=s1; h=MIME-Version:References:In-Reply-To:Message-Id:Cc:To:Subject:From: Date:From:To:Subject:Date:Message-ID:Reply-To; bh=URoXoNLC5/ZoioacUDvP4w5F1qb1ezwOK73xGk96/fc=; b=LcOpyL1MWbBf7+064gI1UaR3Pv Hnl92Z3d2c/ia4R0zfEMhP/a5oQy2XKGD3J16BoPAL7oSi+8bbyBPRaKvSNi4z4/D87D9PraQcdzX E7ZkFGcG3i7y+FTEy9KXZrDA31HlZMFFur/wNaDOSPuk9F3a3MLTG0BCPmHKmIMB71XVzQfEr28W1 51sgq4dmWStCQCdGzehuvVHc0GWIpIkeqXyULpfclkEQqImXVPjI29QagscO5IZUqb9Ru+CG2F+70 X6+YhiGOHf5lJQcAARdp5ykEp1QDq7NQNRNKacLlHj/BkRlA9ZcfNcF2TjKZU4zN88VIkgGgvJfT7 YWokDVWQ==; Received: from [212.51.153.89] (helo=[192.168.12.232]) by mx.dolansoft.org with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1pv6W1-000acb-1J; Sat, 06 May 2023 01:15:13 +0000 Date: Sat, 06 May 2023 03:15:07 +0200 From: Lorenz Brun Subject: Re: Quirks for exotic SFP module To: Andrew Lunn Cc: netdev@vger.kernel.org, Russell King Message-Id: <75Q7UR.PII4PI72J55K3@brun.one> In-Reply-To: <8adbd20c-6de0-49ab-aabe-faf845d9a5d9@lunn.ch> References: <7ed07d2e-ef0e-4e27-9ac6-96d60ae0e630@lunn.ch> <8adbd20c-6de0-49ab-aabe-faf845d9a5d9@lunn.ch> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Sender: lorenz@dolansoft.org X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Am Sa, 6. Mai 2023 um 03:05:10 +02:00:00 schrieb Andrew Lunn : >> I tested and I got a bunch of addresses showing up on i2c master >> connected >> to the module. 1b, 30, 31, 34, 35, 36, 50 and 53. But I'm still not >> sure why >> we'd want to talk MDIO with this module. AFAIK MDIO is an Ethernet >> thing, >> the module is talking G.fast to the outside which is a completely >> different >> protocol from a completely different family of protocols. It has >> its own >> management protocol which runs over Ethernet. > > One reason you might want to talk to the PHY is to correct is > configuration. 1000Base-X includes inband signalling. There are some > Copper SFP which have the inband signalling disabled. And that can > make the host unhappy, it fails to link up. It varies from host to > host. Some work, some don't. Oh, so you're talking about signalling on the AR8033 <-> Linux Host part of the link. I actually wasn't aware that 1000Base-X did in-band signalling, TIL. Since the I2C bus is connected to the modem SoC it would have to forward any MDIO to the AR8033 transceiver, right? This would also be a bit weird as the AR8033 is connected "backwards", i.e. with RGMII facing towards the Modem SoC and 1000Base-X towards the Linux host. Regards, Lorenz