Re: [i2c] [PATCH] update module-init-tools to support the i2c subsystem

From: Jon Smirl
Date: Mon Jan 14 2008 - 09:26:16 EST


On 1/14/08, Geert Uytterhoeven <Geert.Uytterhoeven@xxxxxxxxxxx> wrote:
> On Sun, 13 Jan 2008, Jon Smirl wrote:
> > On 1/13/08, Jean Delvare <khali@xxxxxxxxxxxx> wrote:
> > > On Sun, 13 Jan 2008 11:26:07 -0500, Jon Smirl wrote:
> > > > On 1/13/08, Jean Delvare <khali@xxxxxxxxxxxx> wrote:
> > > > > On Sun, 13 Jan 2008 10:14:14 -0500, Jon Smirl wrote:
> > > > > > On 1/13/08, Jean Delvare <khali@xxxxxxxxxxxx> wrote:
> > > > > > > On Mon, 17 Dec 2007 21:39:37 -0500, Jon Smirl wrote:
> > > > > > > > Follow on to: "Series to add device tree naming to i2c"
> > > > > > > > Teach module-init-tools about the i2c subsystem.
> > > > > > >
> > > > > > > Can you please explain what this patch does and why it is needed?
> > > > > >
> > > > > > It generates the entries needed for the user space module tools to
> > > > > > work with the aliases. For example modprobe/depmod. It is a standard
> > > > > > part of the kernel module system.
> > > > >
> > > > > What entries, where? What can you do after applying your patch that you
> > > > > couldn't do before?
> > > >
> > > > The drivers you are testing with don't depend on other drivers.
> > >
> > > They do. I'm testing with the lm90 driver, which depends on the hwmon
> > > driver. Both load automatically when the underlying i2c-parport driver
> > > instantiate an "adm1032" i2c device.
> >
> > I don't know exactly what those modules tables are used for. I just
> > copied what the other subsystems do. Maybe they are used when you make
> > an initrd to know which drivers to copy into the image.
>
> Module-init-tools needs those table to create module aliases in the *.ko
> files from the MODULE_DEVICE_TABLE(), so udev can load the modules based
> on the device IDs when the devices appear in sysfs.
>
> That's the generic part. How this applies to i2c devices on platforms
> without Open Firmware device trees is another question. I guess that's
> where Jean gets confused (i2c_device_id got _removed_ last year,
> because it didn't make sense (at the time?)).

Last year i2c modules weren't dynamically loadable so it wasn't needed.

>
> With kind regards,
>
> Geert Uytterhoeven
> Software Architect
>
> Sony Network and Software Technology Center Europe
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--
Jon Smirl
jonsmirl@xxxxxxxxx
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