From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Subject: Re: [PATCH 1/4] i2c: imx: check busy bit when START/STOP Date: Fri, 2 Oct 2009 09:26:43 +0200 Message-ID: <20091002072643.GH27039@pengutronix.de> References: <1254359613-21210-1-git-send-email-linuxzsc@gmail.com> <4e090d470910010103o611d9fb2t3acf93632216fc88@mail.gmail.com> <20091001083831.GD27039@pengutronix.de> <4e090d470910010211k4ce78763i1a5163ec6ea57fe8@mail.gmail.com> <20091001095239.GE27039@pengutronix.de> <4e090d470910010754r1ebc4455u6220ccfd803491b0@mail.gmail.com> <20091001163753.GA20103@pengutronix.de> <4e090d470910011757g261c693ehdca40ce43ebee2ec@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <4e090d470910011757g261c693ehdca40ce43ebee2ec-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Richard Zhao Cc: Wolfram Sang , kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Fri, Oct 02, 2009 at 08:57:04AM +0800, Richard Zhao wrote: > On Fri, Oct 2, 2009 at 12:37 AM, Wolfram Sang = wrote: > >> > Ah, so 'make the driver work on i.MX51' is a good statement whic= h should > >> > be part of the commit message. > >> Well, maybe I can mention it. > >> But I think the good point is to present what you modified, not th= e side effect. > > > > It is not the side effect but the intention :) As no code is change= d without a > > need, the reason really should be in the patch description. > No, it's not intention. I'm just trying to make the controller work i= n > a right way. Without this patch, maybe some other fast cpus have > problem too. I just tested mx31 and mx51. I will add "Without this > patch, i2c on some fast SoCs (for example imx51) will not work". Is i= t > ok for you? Please remember that we do not have i.MX51 support in mainline, so this is irrelevant atm. > > > >> Yes. But I don't have multi-master system. So I can't say that. > >> The code is just taken from Freescale latest code. Without it, It > >> could also cause a device error. I forget the details. =A0Anyway, = it > >> doesn't make anything wrong. > > > > Do you know where the details are explained? > No, I don't. I don't have device in hand now. If you have, could you > please help do a simple test? > Use hw to simulate multi-master system. Before execute xfer, you firs= t > pull down SDA, then pull down SDC. It simulates a START. and execute > xfer to see whether IBB is set? No, we won't do any tests on hardware. At the moment we have a driver which is not multi master capable. Looking at the datasheet the change you do seems not enough to change this. So we should take a patch which changes something from which you think it might be needed? And you don't even have the details at hand? No. Sascha --=20 Pengutronix e.K. | = | Industrial Linux Solutions | http://www.pengutronix.de/= | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 = | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-555= 5 |