It's naturally expected that when there are multiple phandle entries specified in pinctrl-* property, these entries will be applied sequentially. And this is how Linux kernel works. So let's define this behavior in the binding doc.
The behavior is useful when people want to reuse a group of predefined pins with only minor configuration adjustment on one particular pin. They will only need to add another entry after the predefined one with needed configuration on that particular pin to overwrite the predefined configuration. Signed-off-by: Shawn Guo <[email protected]> --- .../bindings/pinctrl/pinctrl-bindings.txt | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt index 1958ca9..404ba32 100644 --- a/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt @@ -50,7 +50,13 @@ pinctrl-0: List of phandles, each pointing at a pin configuration entries may exist in this list so that multiple pin controllers may be configured, or so that a state may be built from multiple nodes for a single pin controller, each - contributing part of the overall configuration. See the next + contributing part of the overall configuration. These entries + will be applied sequentially. If there are multiple entries + contributing the configuration of the same pin, the latter + will overwrite the former. However, this 'overwrite' mechanism + should be used with the caution that it could cause some ill + effect, e.g. a glitch on the pin when pull down/up setting + gets flipped in this 'overwrite'. See the next section of this document for details of the format of these pin configuration nodes. -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
