On Mon, 4 Feb 2008 23:01:55 +0000 Ben Dooks <[EMAIL PROTECTED]> wrote:
> 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. Oki > > 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. > Will take a look at that. > > 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. > Im trying to move the companion chip hd64461 to a more sensible location. Paul suggested building an mfd driver. The hd64461 chipset supplies for example pcmcia and framebuffer support. Its not as advanced as the SM501. > 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. Oki, sounds good. Thanks for info. > > -- > 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/
