On Sun, Mar 13, 2011 at 03:04:11PM -0400, Ben Gamari wrote: > I've included the OMAP list so that I can hopefully get some feedback > from folks more familiar with this code. > > Background: > > I've been working on adding support for GPIO chip select lines to the > McSPI driver. Grant has been working with me to try getting the > in-kernel interface right and we have finally converged on a solution > whereby a table of GPIO lines will be passed to the McSPI driver through > platform_device.device.platform_data. Unfortunately, as explained below, > there is no clear path to support this in the current McSPI > initialization code. > > > On Thu, 03 Mar 2011 14:42:07 -0700, Grant Likely <grant.likely@xxxxxxxxxxxx> wrote: > > The spi_master platform device is registered somewhere in the > > inappropriate support code. You need to arrange to make sure the > > correct pdata is attached to it when it gets registered. There > > /should/ be a mechanism for doing so. > > > > All spi devices already specify a cs number anyway. What you can do is > > use the cs number as the lookup index into the gpio table, and > > remember to reserve a cs# for the 'native' cs line. > > > I've done as you suggested and added support to the McSPI driver by > passing a GPIO table through platform_data. A patch will be coming > shortly. > > Unfortunately, I'm really not sure how to restructure the OMAP code to > pass this information along. Currently the McSPI devices are registered > in arch/arm/mach-omap2/devices.c (omap_init_mcspi). In order to make the > GPIO CS support configurable by board code, we need some way to change > the (currently static) platform_devices prior to registration. Does > anyone have any suggestions on how this code could be refactored to > allow for this with minimal code duplication? Obviously we could just > move the platform_devices into the board files but this seems like a lot > of code duplication to support functionality that few boards will use. I see two solutions: 1) platform code registers a bus notifier so that it gets called back before the device gets bound to a driver. Then it can augment the platform data. 2) add an api to arch/arm/mach-omap2/devices.c for providing a cs table before the device gets registered (must be called before arch_initcall() time). g. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
