From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH] i2c: Floppy controller bus driver (V0.2) Date: Mon, 18 Aug 2008 20:57:08 +0200 Message-ID: <20080818205708.324961c4@hyperion.delvare> References: <20080818031046.GE8052@MAIL.13thfloor.at> <20080818104539.480ba532@hyperion.delvare> <20080818164053.GA32376@MAIL.13thfloor.at> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080818164053.GA32376-ZD0Mn47LIGX0Pe/G4T7+5F6hYfS7NtTn@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org Errors-To: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org To: Herbert Poetzl Cc: I2C ML List-Id: linux-i2c@vger.kernel.org Hi Herbert, On Mon, 18 Aug 2008 18:40:53 +0200, Herbert Poetzl wrote: > On Mon, Aug 18, 2008 at 10:45:39AM +0200, Jean Delvare wrote: > > On Mon, 18 Aug 2008 05:10:46 +0200, Herbert Poetzl wrote: > > > diff -NurpP --minimal linux-2.6.27-rc3/drivers/i2c/busses/Kconfig linux-2.6.27-rc3-fi2c-v0.2/drivers/i2c/busses/Kconfig > > > --- linux-2.6.27-rc3/drivers/i2c/busses/Kconfig 2008-08-15 21:19:24.000000000 +0200 > > > +++ linux-2.6.27-rc3-fi2c-v0.2/drivers/i2c/busses/Kconfig 2008-08-18 03:46:31.000000000 +0200 > > > @@ -490,6 +490,22 @@ config I2C_VERSATILE > > > > > > comment "External I2C/SMBus adapter drivers" > > > > > > +config I2C_FLOPPY > > > + tristate "Floppy controller adapter" > > > + select I2C_ALGOBIT > > > + default n > > > + help > > > + This supports a simple do-it-yourself floppy controller to > > > + I2C adapters using the motor control lines for SDA and SCL, > > > + and the drive change input for SDA readback. > > > + > > > + This support is also available as a module. If so, the module > > > + will be called i2c-floppy. > > > + > > > + If you do not have such a device, and do not plan to build one, > > > + it's safe to say N here. Do not say Y here and to the floppy > > > + driver unless you know exactly what you are doing. > > > > Good point. In fact it would be safer to depend on !BLK_DEV_FD. There's > > no "if you know exactly what you are doing" that holds: if any of these > > drivers is built in, the other one _must_ be excluded. > > well, actually not true ... I build both drivers > as module, and can then decide wether I want to > attach a floppy or an I2C adapter ... and except > for the fact that floppy access to the I2C adapter > is not the best idea, this works perfectly fine What I propose wouldn't prevent you from doing that. "depend on !BLK_DEV_FD" means that both drivers can't be built-in. Both drivers as modules is OK. Remember that the Kconfig language is based on ternary logic. > > but as far as I know, there is no (sane) way to > say building both 'M' is fine, but 'Y' is a nono > (I think that is why many drivers write it this > way in the help) There _is_ a way do to this and that's exactly what I proposed. > > making it mutually exclusive is kind of problematic > as you need to disable one _beforehand_ to see the > other in the config ... This is true, but I don't expect this to be a problem in practice. Most users have the standard floppy driver built as module, so they will see i2c-floppy and will be able to build it as a module. Worst case is if the standard floppy driver is built-in, but I don't expect this to be a popular choice these days, with all the PCs out there without a floppy disk drive. If this is really a problem, it's easy to add a message in Kconfig to tell people what they need to do to get access to i2c-floppy. But I don't expect your driver to be popular enough to warrant this. > magically disabling the > floppy driver from the i2c-floppy is not an option > either, as the build system doesn't support that Agreed. Even if the build system could do that, this would be highly unfriendly. > > so I personally think the 'default n' + warning > is fine for everyday use, but of course, the final > call is yours I'll add the dependency. If I don't, somebody will quickly complain that floppy support is broken by allyesconfig. No need to resend, I'll do that in a incremental patch. I think I'll add a dependency on EXPERIMENTAL as well - after all your driver has seen little testing so far. -- Jean Delvare _______________________________________________ i2c mailing list i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org http://lists.lm-sensors.org/mailman/listinfo/i2c