On Wed, Mar 29, 2017 at 4:55 PM, Chris Brandt <chris.bra...@renesas.com> wrote: > On Wednesday, March 29, 2017, Linus Walleij wrote: >> On Fri, Mar 24, 2017 at 4:22 PM, Jacopo Mondi <jacopo+rene...@jmondi.org> >> wrote: >> >> > Add dt-bindings for Renesas r7s72100 pin controller header file. >> > >> > Signed-off-by: Jacopo Mondi <jacopo+rene...@jmondi.org> >> >> > +/* >> > + * Pin is bi-directional. >> > + * An alternate function that needs both input/output functionalities >> > +shall >> > + * be configured as bidirectional. >> > + * Eg. SDA/SCL pins of an I2c interface. >> > + */ >> > +#define BI_DIR (1 << 3) >> >> Any specific reason why this should not simply be added to >> include/linux/pinctrl/pinconf-generic.h >> as PIN_CONFIG_BIDIRECTIONAL and parsed in drivers/pinctrl/pinconf- >> generic.c from the (new) DT property "bidirectional" simply? > > I see your point. It would cut down from every driver out there > inventing some new property or config instead of everyone just sharing > a fixed set. > Maybe someone else out there will end up having a need for a > "bidirectional" option.
I was thinking about that one. It is a bit weird electrically, like what kind of electronics is really bidirectional? It seems like a fancy name for open drain/open source, what we call "single ended" configuration. (See docs in Documentation/gpio/driver.txt) It would be great if you could check if that is what they mean, actually. > But, what do we do for Ethernet? All the pins are "normal" except just > the MDIO pin needs to be bidirectional. I see Geert clarified what we could do here. Yours, Linus Walleij
