On 09/13/2013 01:53 AM, Boris BREZILLON wrote: > AT91 SoCs do not support per pin debounce time configuration. > Instead you have to configure a debounce time which will be used for all > pins of a given bank (PIOA, PIOB, ...). > diff --git a/Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt > +Optional properties for iomux controller: > +- atmel,default-debounce-div: array of debounce divisors (one divisor per bank) > + which describes the debounce timing in use for all pins of a given bank > + configured with the DEBOUNCE option (see the following description). > + Debounce timing is obtained with this formula: > + Tdebounce = 2 * (debouncediv + 1) / Fslowclk > + with Fslowclk = 32KHz > + > Required properties for pin configuration node: > - atmel,pins: 4 integers array, represents a group of pins mux and config > setting. The format is atmel,pins = <PIN_BANK PIN_BANK_NUM PERIPH CONFIG>. > @@ -91,7 +99,6 @@ DEGLITCH (1 << 2): indicate this pin need deglitch. > PULL_DOWN (1 << 3): indicate this pin need a pull down. > DIS_SCHMIT (1 << 4): indicate this pin need to disable schmit trigger. > DEBOUNCE (1 << 16): indicate this pin need debounce. > -DEBOUNCE_VAL (0x3fff << 17): debounce val. This change would break the DT ABI since it removes a feature that's already present. I suppose it's still up to the Atmel maintainers to decide whether this is appropriate, or whether the impact to out-of-tree DT files would be problematic. Assuming the DT ABI can be broken, I think I'd prefer to do so, rather than take "non-alt" patch 4/4, since a per-pin DEBOUNCE_VAL clearly doesn't correctly model the HW, assuming the patch description is correct. I don't think arguments re: the generic pinconf debounce property hold; if the Linux-specific/internal generic property doesn't apply, the DT binding should not be bent to adjust to it, but should rather still represent the HW itself. -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
