From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hui Wang Subject: Re: [PATCH v2 2/2] net: flexcan: add transceiver switch gpios support Date: Mon, 2 Jul 2012 10:55:55 +0800 Message-ID: <4FF10DBB.1020106@gmail.com> References: <1340853701-4488-1-git-send-email-shawn.guo@linaro.org> <1340853701-4488-3-git-send-email-shawn.guo@linaro.org> <4FEC329C.7070004@pengutronix.de> <20120628112111.GC22990@S2101-09.ap.freescale.net> <4FEC400F.8010506@pengutronix.de> <20120628114108.GD22990@S2101-09.ap.freescale.net> <20460.18717.17688.965250@ipc1.ka-ro> <20120628121302.GI22990@S2101-09.ap.freescale.net> <20460.19712.158996.397146@ipc1.ka-ro> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail.windriver.com ([147.11.1.11]:43345 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932118Ab2GBC4g (ORCPT ); Sun, 1 Jul 2012 22:56:36 -0400 In-Reply-To: <20460.19712.158996.397146@ipc1.ka-ro> Sender: linux-can-owner@vger.kernel.org List-ID: To: =?UTF-8?B?TG90aGFyIFdhw59tYW5u?= Cc: Shawn Guo , Marc Kleine-Budde , Hui Wang , "David S. Miller" , linux-arm-kernel@lists.infradead.org, linux-can@vger.kernel.org Lothar Wa=C3=9Fmann wrote: > Hi, > > Shawn Guo writes: > =20 >> On Thu, Jun 28, 2012 at 02:07:57PM +0200, Lothar Wa=C3=9Fmann wrote: >> =20 >>> Hi, >>> >>> Shawn Guo writes: >>> =20 >>>> On Thu, Jun 28, 2012 at 01:29:19PM +0200, Marc Kleine-Budde wrote: >>>> =20 >>>>> I mean which name is more precise, do these gpio enable/standy a = "phy" >>>>> or a "transceiver". For example: >>>>> http://www.nxp.com/documents/application_note/AN00094.pdf, this d= ocument >>>>> says: TJA1041/1041A high speed CAN transceiver. >>>>> >>>>> =20 >>>> Isn't term "phy" (physical interface) generally meant to be the sa= me >>>> thing as "transceiver"? I just happened to like the shorter one a= s >>>> what Hui did in his patch. >>>> >>>> But it does not really matter to me, will change the name since yo= u >>>> care about it. >>>> >>>> =20 >>> A transceiver is just a dumb piece of hardware, while a PHY contain= s >>> some intelligence of its own. >>> >>> =20 >> Then, it sounds more like a PHY than transceiver, since it's an IC >> chip with some control over it. >> >> =20 > The 'I' in 'IC' does not stand for 'intelligent', but for > 'integrated'. ;) > A can transceiver is usually merely a switchable buffer. There are no > registers to configure it or an internal processor that does some > magic. > > =20 Sorry for reply late, in my first patch, i chose "phy" instead of "xcvr= "=20 because the MC33902 datasheet tell me it is a "high speed CAN physical=20 interface", and it includes "an internal 5.0 V supply for the CAN bus=20 transceiver". And from the diagram in the page 1 of the MC33902 datasheet, the MC3390= 2=20 includes bus xcvr, i/o control logic, power supply and external=20 regulator control logic. As a result i decided to use phy in the driver= =2E Regards, Hui. > Lothar Wa=C3=9Fmann > =20