Re: [PATCH] Add sysfs support to the IPMI driver

From: Corey Minyard
Date: Sun Mar 13 2005 - 18:00:42 EST

Greg KH wrote:

On Sat, Mar 12, 2005 at 10:57:24PM -0600, Corey Minyard wrote:

The IPMI driver has long needed to tie into the device model (and I've long been hoping someone else would do it). I finally gave up and spent the time to learn how to do it. I think this is right, it seems to work on on my system.

Looks good. One minor question:

+ snprintf(name, sizeof(name), "ipmi%d", if_num);
+ class_simple_device_add(ipmi_class, dev, NULL, name);

What do ipmi class devices live on? pci devices? i2c devices?
platform devices? Or are they purely virtual things?

Good question. I struggled with this for a little while and decided the class interface was important to have in first and I'd figure out the rest later. They live in different places depending on the particular low-level interface. Some live on the I2C bus (and will show up there in sysfs with the I2C driver). Some live on the ISA bus, some are memory-mapped, some are on the PCI bus (though there is not a driver for PCI support yet), and some sit on the end of a serial port (driver is in the works). I know, it's a mess, but there's not much I can do about these crazy hardware manufacturers.

I wasn't sure where to handle all this. The I2C and PCI bus side of things should be handled. However, the others probably need to sit someplace on a bus, right? That should probably be handled in the low-level code that actually knows where the hardware sits.


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