Re: [RFC/PATCH 1/2] mfd: twl6030-irq: move to threaded_irq

[Mark Brown <broonie@opensource.wolfsonmicro.com>]

On Tue, Dec 28, 2010 at 09:40:03AM -0800, David Brownell wrote:

> > What I'd expect to see from a conversion like this would be
> > that most of
> > the locking/IRQ management stuff would be dropped

> I'd expect that genirq solve all the issues and
> that its support be used.  That's not the same
> as dropping anything except the initial code to
> handle what genirq didn't ... some locking/etc
> would still mostly need doing, but where genirq
> now handles it, that'd be preferable.

It should solve everything - there's rather a lot of I2C/SPI connected
MFDs using genirq fully now without any hassle, the APIs are really
straightforward and easy to use.

>  and the
> > bus_lock() and
> > bus_sync_unlock() operations would be implemented.

> ISTR maybe four or five genirq updates in the
> area of threaded IRQ management, added so that
> issues the twl4030 driver needed to be solved
> could be solved in generic ways.

Yup - the main one on top of threaded IRQs was the bus_lock() and
bus_sync_unlock() methods.

> The first was just having threaded IRQ handlers,
> and another was I think removing the initial
> quick'n'dirty thread-per-irq restriction; there
> was no point in having a few dozen IRQ threads
> in e.g. a twl4030 driver, since two could never
> do constructive work concurrently.

The thread per IRQ thing is dealt with too, the secondary IRQs share the
thread used for demux.