On Fri, Oct 2, 2009 at 3:26 PM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: > On Fri, Oct 02, 2009 at 08:57:04AM +0800, Richard Zhao wrote: >> On Fri, Oct 2, 2009 at 12:37 AM, Wolfram Sang <w.sang@xxxxxxxxxxxxxx> wrote: >> >> > Ah, so 'make the driver work on i.MX51' is a good statement which 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 the side effect. >> > >> > It is not the side effect but the intention :) As no code is changed 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 in >> 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 it >> ok for you? > > Please remember that we do not have i.MX51 support in mainline, so this > is irrelevant atm. So I don't need to meantion mx51? "Without this patch, i2c on some fast SoCs will not work" is all right? > >> > >> >> 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. Anyway, 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 first >> 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. Ok, It seems I have no reason to keep the busy wait before START. Wolfram, do you agree to remove the busy wait? I saw you submmited the original driver. Let get away from multi-master. There's nearly no multi-master i2c bus system in reality. Thanks Richard > > Sascha > > -- > 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: +49-5121-206917-5555 | > -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
