Hi Arnd, On 03/20/2012 02:01 PM, Arnd Bergmann wrote: >> Maybe the right thing is a common low-level isp1301 interface defining >> all the registers and providing low-level (I2C) access functions, >> leaving all the "higher level"/"board specific" functions up to the >> existing drivers? >> >> (I guess you meant drivers/usb/otg/isp1301_omap.c ?) > > Yes, that sounds like a very good idea. Can you describe which part of > the function isp1301 does? It's not clear how the layering between > that and the platform driver should end up. The ISP1301 is a relatively simple transceiver where the actual differential USB signals end up being generated/decoded. It contains some registers and is controlled via I2C to manipulate electrical settings (pull up / power etc.). At a first glance, I found the following drivers to be using it: ohci-nxp (was: ohci-pnx4008 + ohci-lpc32xx) isp1301_omap lpc32xx_udc (WIP) The common functions that all of them are using are some low-level functions like read/write byte, read/write word. (For ohci-nxp, I used smbus commands.) I propose exporting just the defines for all the registers and their bits together with some accessor functions. Would those be the correct places for header and driver: drivers/usb/misc/isp1301.c include/linux/usb/isp1301.h ? As an example usage, I would let the next update of the lpc32xx_udc use it and separately provide patches to make the other drivers above also use it. Thanks in advance, Roland -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
