Am Sonntag, 16. Juni 2013, 12:26:38 schrieb Linus Walleij: > On Fri, Jun 14, 2013 at 5:42 PM, Heiko Stübner <he...@sntech.de> wrote: > > The BIAS_DISABLE and BIAS_HIGH_IMPEDANCE generic pinconfig options were > > missing information about their argument - which should be ignored. > > > > Also the BIAS_PULL_* options may have the pull strength as argument > > when they are activated, while simpler hardware can use any > > non-0 value for it. > > > > Update the kerneldoc to reflect this. > > > > Signed-off-by: Heiko Stuebner <he...@sntech.de> > > I'm holding this patch off. > > > * @PIN_CONFIG_BIAS_PULL_UP: the pin will be pulled up (usually with > > high > > > > - * impedance to VDD). If the argument is != 0 pull-up is enabled, > > - * if it is 0, pull-up is disabled. > > + * impedance to VDD). If the argument is != 0 pull-up is enabled. On > > + * hardware supporting this, the argument should contain the > > strength of + * the pull in Ohm. If it is 0, pull-up is disabled. > > As noted by Laurent, a pull-up of 0 Ohm is a short-circuit (bascially the > TOTAL pull-up) and it is pretty counter-intuitive to have that mean > "disable pull-up". Can we avoid this? > > > * @PIN_CONFIG_BIAS_PULL_DOWN: the pin will be pulled down (usually with > > high > > > > - * impedance to GROUND). If the argument is != 0 pull-down is > > enabled, - * if it is 0, pull-down is disabled. > > + * impedance to GROUND). If the argument is != 0 pull-down is > > enabled. On + * hardware supporting this, the argument should > > contain the strength of + * the pull in Ohm. If it is 0, pull-down > > is disabled. > > Dito. > > > * @PIN_CONFIG_BIAS_PULL_PIN_DEFAULT: the pin will be pulled up or down > > based * on embedded knowledge of the controller, like current mux > > function. > > > > - * If the argument is != 0 pull up/down is enabled, if it is 0, > > - * the pull is disabled. > > + * If the argument is != 0 pull up/down is enabled. On hardware > > supporting + * this, the argument should contain the strength of the > > pull in Ohm. + * If it is 0, pull is disabled. > > Dito. > > Can't we rely on PIN_CONFIG_BIAS_DISABLE for all this?
you're the boss on this, I'll do whatever you say :-) I was going after the existing documentation of "bias-pull-X = <0>" being there to turn off this specific bias. So when reading the existing doc I was assuming somebody had needed this in the past. Actually I'm too more comfortable with only using bias-disable. So I'll redo this patch to remove the disabling of a pull via this method, if that's the right way to go. Same with the rockchip driver. Heiko _______________________________________________ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss
