Hi, On Wed, Apr 06, 2011 at 03:09:00PM -0700, Greg KH wrote: > On Wed, Apr 06, 2011 at 09:59:02PM +0300, Felipe Balbi wrote: > > Hi, > > > > On Wed, Apr 06, 2011 at 08:47:34PM +0200, Samuel Ortiz wrote: > > > > > > What is a "MFD cell pointer" and why is it needed in struct device? > > > > > An MFD cell is an MFD instantiated device. > > > > > MFD (Multi Function Device) drivers instantiate platform devices. > > > > > Those > > > > > devices drivers sometimes need a platform data pointer, sometimes an > > > > > MFD > > > > > specific pointer, and sometimes both. Also, some of those drivers > > > > > have been > > > > > implemented as MFD sub drivers, while others know nothing about MFD > > > > > and just > > > > > expect a plain platform_data pointer. > > > > > > > > That sounds like a bug in those drivers, why not fix them to properly > > > > pass in the correct pointer? > > > Because they're drivers for generic IPs, not MFD ones. By forcing them to > > > use > > > MFD specific structure and APIs, we make it more difficult for platform > > > code > > > to instantiate them. > > > > I agree. What I do on those cases is to have a simple platform_device > > for the core IP driver and use platform_device_id tables to do runtime > > checks of the small differences. If one platform X doesn't use a > > platform_bus, it uses e.g. PCI, then you make a PCI "bridge" which > > allocates a platform_device with the correct name and adds that to the > > driver model. > > > > See [1] (for the core driver) and [2] (for a PCI bridge driver) for an > > example of what I'm talking about. > > Yes, thanks for providing a real example, this is the best way to handle > this.
no problem. ps: that's the driver for the USB3 controller which will come on OMAP5. Driver being validate on a pre-silicon platform right now :-D In a few weeks I'll send the driver for integration. -- balbi -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
