Messages in this thread | | | Date | Tue, 9 Jul 2013 07:32:43 -0500 | From | Nishanth Menon <> | Subject | Re: [PATCHv3 2/3] drivers: spi: Add qspi flash controller |
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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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