On Wednesday, September 15, 2010 01:15:08 Donghwa Lee wrote: > On Tuesday, September 14, 2010 20:48:11 Mike Frysinger wrote: > > On Tuesday, September 14, 2010 03:38:11 Donghwa Lee wrote: > >> This patch adds basic support for spi mode 0~3 by control gpio bitbang > >> in S5P. Original name of this patch was "support spi gpio driver by > >> control gpio bitbang". But, it had arch-specific features, S5P, so > >> changed to this name. > > > > so why arent you implementing this with the common spi API ? then any of > > the code in the tree would be able to use this spi driver without having > > to change to your arch-specific API. > > I think common spi API is not appropriate for S5P arch. For example, > arch-S5P gpio framework consists of many gpio bank structure, and gpio > number. From here, gpio bank structures are groups of many gpio pin and > gpio number indicates specific gpio pin of gpio bank group. To control any > gpio pin in arch S5P, must know about gpio bank and its specific number. > But, existing spi API is different from avobe. > For example, spi_setup_slave() function, consists of 4 function parameter, > bus, cs, max_hz and mode. bus and cs is specific gpio number that not gpio > bank group. so I think it is hard to control gpio without modifying API > format.
i dont see how this matters. implement the common gpio api and handle the binding of a unique number to specific bank/pin there. then the spi/gpio layer need not care about how gpios are implement on any arch. the Blackfin port already does this. each variant has a different number of gpio ports with a different number of pins in each bank. you can see in arch/blackfin/include/asm/mach-*/gpio.h how we then normalize the banks/pins into numbers from 0 to <gpio max for that arch>. then spi layer simply says "give me gpio 12" and the gpio layer takes care of the port/pin layer. -mike
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