On Sat, 12 Feb 2011 01:33:24 -0700, Grant Likely <[email protected]> wrote: > (Sorry for the really laggy reply) > No worries, I was just starting to think about this again myself.
> I don't see it being that big a deal. gpio drivers are pretty > lightweight and it is fine to have domain-specific limitations on how > gpios for a particular "gpio controller" behave. In your example, if > the hardware doesn't support enabling 2 CS pins at once, then you make > a choice, either setting one when the other is already set simply does > not work; or it could reset the other state. Either choice would be > fine. The SPI driver must do the right thing regardless and deselect > the previous CS line before enabling a new one. > Having now finally having had a chance to implement a gpio_chip driver, I agree. It's quite simple and seems to fill the need pretty well > The other alternative would be to implement a new SPI chipselect > common infrastructure, but IMO, that would just end up looking like a > duplication of the gpio infrastructure. > I think you are probably right. GPIO seems to be a good fit. Patch coming shortly. I use spi_board_info.controller_data to pass the gpio number to the controller which doesn't seem like the best way forward, but I wasn't sure how else to proceed. Also, since the gpio numbers are dynamically determined spi_board_info.controller_data must be filled in at runtime, which is also a bit of a bummer (although not easily solved as far as I can tell). Let me know what you think. - Ben ------------------------------------------------------------------------------ The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE: Pinpoint memory and threading errors before they happen. Find and fix more than 250 security defects in the development cycle. Locate bottlenecks in serial and parallel code that limit performance. http://p.sf.net/sfu/intel-dev2devfeb _______________________________________________ spi-devel-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/spi-devel-general
