On Tue, Jun 4, 2013 at 2:05 PM, Heiko Stübner <heiko@xxxxxxxxx> wrote: >> > +PULL_AUTO (1 << 0): indicate this pin needs a pull setting for SoCs >> > + that determine the pull up or down themselfs >> >> Hm, never saw that before... > > Citing the original gpio driver: > > /* > * Values written to this register independently > * control Pullup/Pulldown or not for the > * corresponding data bit in GPIO. > * 0: pull up/down enable, PAD type will decide > * to be up or down, not related with this value > * 1: pull up/down disable > */ > > So if it's a pull up or down is decided based on the mux of the pin. Calling > everything a "pull down" (or up) when it isn't seemed somehow wrong to me. > > The rk3188 on the other hand supports both pull up and down separately. > > Or should this be selected as PULL_UP | PULL_DOWN in the config? The generic config is pretty much either/or so it'd be a new config for that approach. Basically it seems they have embedded knowledge into the silicon: there is no specific rule as to whether a pad should be pulled up or down depending on "pad type" as is stated, rather it's so that if you know a pad will be used for I2C SCL then you know it needs pull-up. Probably something like a "1" on some constant switch in VHDL/Verilog is hard-coded into the silicon turning on pull-up if I2C is selected and the autopull is set for example. >> +config PINCTRL_ROCKCHIP >> + bool >> + select PINMUX >> + select PINCONF >> + select GENERIC_IRQ_CHIP >> >> Why is this super-simple pin config thing not using >> GENERIC_PINCONF? >> >> I *know* it is simpler to implement your own thing, but think of the >> poor maintainers that have to wade through 50 identical implementations. >> Do this, it pays off. > > generic pinconf sounds interesting ... will give it a try. > > The only problem is the pull stuff mentioned above that is either pull up or > down without the driver having knowledge about it. And generic_pinconf only > knows about them separately right now. Create a separate patch adding PIN_CONFIG_BIAS_PULL_AUTO to include/linux/pinctrl/pinconf-generic.h, don't forget the kerneldoc, and patching drivers/pinctrl/pinconf-generic.c. I'll apply it right away. >> Nothing else you want to say about the pins here? >> (No big deal for sure, but....) > > when using pinconfig_generic, its dump_pin function should be more talkative > right? Yes, one of the things you get for free... soon also the pin config DT parser will be for free I hope. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
