On Mon, Feb 04, 2008 at 12:37:14PM +0100, Kristoffer Ericson wrote: > Greetings, > > Trying to wrap my head around sm501. From what I can tell an mfd driver is a > "master" driver that takes control of all > memory and io areas. It then hands out areas of those to drivers. Anywhere > near correct?
Yes, it is the central management for these, but also ensures that any of the sub-drivers have properly locked access to the clocks, gpio and other shared resources. The mfd driver for the sm501 exports a number of functions for the sub drivers to use, you should be able to see what is exported easily by the fact they are exported with EXPORT_SYMBOL_GPL(). The header files should document basic functionality of this. > I can see some benefit but still hard for me to motivate. What am I missing? > What will the mfd be able to do, that I lack now? > > The sm501 driver seems way more advanced than I will need for hd64461/hd64465 > anyhow, but still need to understand sm501 completely before > attempting to write one on my own. Anyone know any documentation aside from > example drivers? Are you trying to write your own SM501, or something else? It seems you are writing for something else. If the chip you are targetting has shared resources, such as clock gates, PLLs, or gpio that other drivers need to touch, then the best way to go is for an mfd driver to provide this functionality and have all the child drivers use the exported functionality. -- Ben ([EMAIL PROTECTED], http://www.fluff.org/) 'a smiley only costs 4 bytes' -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
