On 07/09/2013 05:05 AM, Mark Brown wrote:
On Tue, Jul 09, 2013 at 09:51:43AM +0300, Felipe Balbi wrote:
Looks like a case to use regmap?
Dumb q: why cant we use regmap_spi? worst case, you should be able to
read regmap-spi and you'll see why it can't be used in this case.
regmap-spi is for SPI clients who want to read their register map
through SPI commands. This is a driver for the SPI master which has its
registers memory mapped.
Indeed, regmap-spi would be a client of this driver. Though there is
regmap-mmio which may be helpful, on the other hand it's relatively
heavyweight and SPI can be a bit performance sensitive so perhaps it's
not awesome here. Russell did mention the idea of some helpers along a
similar style though, they may be a good idea but nobody wrote them yet.
Fair enough. I am starting to see at least a second driver (internally
for DRA7 IRQ/DMA crossbar) doing the same handling for different bit
sized registers. maybe now is the time for us to create a lighter
version of mmio. mmio at least the last I looked uses spinlocks and is
fairly fast. But, I agree, when the client of regmap uses locks to
protect operations of their own, regmap might be a bit of an overhead.
that said, replicating regmap logic in the driver looks a bit weird and
might allow the basis for other drivers to do the same as well as some
users of mmio would consider themselves performance sensitive :(.
--
Regards,
Nishanth Menon
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