* Russell King - ARM Linux wrote: > On Wed, Feb 08, 2012 at 09:15:08AM +0100, Thierry Reding wrote: > > * Ryan Mallon wrote: > > > On 07/02/12 02:19, Thierry Reding wrote: > > > > The total maximum number of PWM devices is currently fixed to 64, but > > > > can easily be made configurable via Kconfig. > > > > > > It would be better to make the code handle arbitrary numbers of PWMs. A > > > Kconfig knob becomes annoying when you have more than one platform > > > configured into the kernel. > > > > AFAICT handling an arbitrary number of PWMs will only be possible once we get > > rid of the global namespace and therefore should be postponed for later. I > > may be wrong, though, so if anybody can point me in the right direction I'm > > perfectly happy to change that in this series. > > One solution would be to look at how genirq handles this. Eg, it uses a > radix tree to store the irqdescs rather than an array, and a bitmap > showing which global numbers are allocated. That's exactly the solution implemented by this second version of the series. In fact I did turn to genirq for inspiration at the time I wrote the code. My understanding was that Ryan proposed to get rid of the bitmap altogether because it arbitrarily limits the number of PWMs. How that can be achieved with a global namespace I don't know. Thus my proposal to keep it as-is for now and get rid of it once per-chip indexing is implemented. Thierry
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