On Tue, Jul 23, 2013 at 05:18:34PM +0200, Simon Guinot wrote: > Hi, > > I am currently working on converting the LED driver leds-netxbig to DT. > Doing so, I am also considering to move the GPIO extension bus functions > (which are currently parts of leds-netxbig) into a separate driver. > > On the LaCie "Big Network" board family (netxbig), the LEDs are > controlled by a CPLD. In turn, the CPLD can be configured (mostly the > LEDs modes) through a kind of parallel GPIO bus, called GPIO extension > bus. Two registers (address and data) are exposed. Each of them is made > up of several GPIOs. An extra GPIO is used to notify the CPLD that the > registers have been updated. The leds-netxbig driver uses some dedicated > functions (prefixed by "gpio_ext_") to handle the GPIO bus extension. > > On the latest "Big Network" boards, this bus is also used to enable the > PM wakeup sources: the CPLD can be asked to keep powered some devices > (as the RTC or the Ethernet PHY) while the board is down. I think it > could be nice to expose this feature to the userland. That's why I am > thinking about moving the GPIO extension bus support into a separate > driver. The problem is that I can't find a proper location for a such > driver. AFAIK, it doesn't fit with anything existing supported by Linux. > Maybe I should consider drivers/bus ? Or even drivers/misc ? iiuc, the CPLD is more of gpio multiplexer/expander. Have you seen 66bcb58 arm: mvebu: enable gpio expander over i2c on Mirabox platform ? And the corresponding driver, drivers/gpio/gpio-pca953x.c? I would try drivers/gpio. If there are complaints, it should be trivial to move it in a new version of the series. Is there any reason why the new capabilities in the "Big Network" boards couldn't be covered by gpio-regulator? thx, Jason. -- To unsubscribe from this list: send the line "unsubscribe linux-leds" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
