Date: Fri, 23 Mar 2001 16:07:14 +0100 From: Nicolas Souchu <nsouch@fr.alcove.com> To: Willem van Engen <wvengen@stack.nl> Cc: freebsd-hackers@freebsd.org Subject: Re: driver: probe not called when smbus child Message-ID: <20010323160714.A11585@ontario.alcove-fr> In-Reply-To: <3AB77C31.8213C158@stack.nl>; from wvengen@stack.nl on Tue, Mar 20, 2001 at 04:50:09PM %2B0100 References: <3AB77C31.8213C158@stack.nl>
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On Tue, Mar 20, 2001 at 04:50:09PM +0100, Willem van Engen wrote:
> I'm trying to write a module which should be a child of the smbus.
> When I make the driver a child of the isa bus, identify, probe,
> and attach functions are properly called. I use the following
> code to do that:
> DRIVER_MODULE(my, isa, my_driver, my_devclass, 0, 0);
> But when I put it on the smbus using
> DRIVER_MODULE(my, smbus, my_driver, my_devclass, 0, 0);
> only identify is called. The identify function is as follows:
>
> static void
> my_identify(driver_t *driver, device_t parent)
> {
> devclass_t dc;
> device_t child;
>
> printf("my: my_identify called\n");
> dc = devclass_find("my");
> if (devclass_get_device(dc, 0)==NULL) {
> child = BUS_ADD_CHILD(parent, 0, "my", -1);
> }
> }
>
> The driver only uses smbus calls, so I think the best parent
> would be smbus.
I'm currently working on this.
> And when I do a smbus_request_bus, the call waits forever as
> it seems. That seems sensible to me, because it asks the
> parent for the bus and the isa bus can't grant requests for
> the smbus. So I think the driver has to be a child of the smbus.
requesting the smbus is needed when the smbus controller potentially
share resources on another bus (like lpbb(4) does on ppbus).
> Looking in the kernel sources, I see that the only smbus child
> I can find, smb, (if there are others, I'm certainly interested)
> is attached in the smbus code itself. So the next question rises:
> Is it possible to have an smbus child in a dynamically loadable
> module (I can't find smbus.ko in /modules, so loading the child
> first and then smbus isn't an option I guess) ?
Currently, smb is the only smbus child. This is due to the fact that
most people prefer programming their SMB chips from user space.
I have a patch and a complete modules/i2c tree for compiling smbus and
smb as modules. You must be interested... But I have to fix some issues
like identification and driver dynamic addition.
--
Nicolas.Souchu@fr.alcove.com
Alcôve - Open Source Software Engineer - http://www.alcove.com
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