diff options
Diffstat (limited to 'Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt | 44 |
1 files changed, 43 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt index b73c96d24f59..bf3f7b014724 100644 --- a/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt @@ -97,6 +97,11 @@ For example: }; == Pin controller devices == +Required properties: See the pin controller driver specific documentation + +Optional properties: +#pinctrl-cells: Number of pin control cells in addition to the index within the + pin controller device instance Pin controller devices should contain the pin configuration nodes that client devices reference. @@ -119,7 +124,8 @@ For example: The contents of each of those pin configuration child nodes is defined entirely by the binding for the individual pin controller device. There -exists no common standard for this content. +exists no common standard for this content. The pinctrl framework only +provides generic helper bindings that the pin controller driver can use. The pin configuration nodes need not be direct children of the pin controller device; they may be grandchildren, for example. Whether this is legal, and @@ -156,6 +162,42 @@ state_2_node_a { pins = "mfio29", "mfio30"; }; +Optionally an altenative binding can be used if more suitable depending on the +pin controller hardware. For hardaware where there is a large number of identical +pin controller instances, naming each pin and function can easily become +unmaintainable. This is especially the case if the same controller is used for +different pins and functions depending on the SoC revision and packaging. + +For cases like this, the pin controller driver may use pinctrl-pin-array helper +binding with a hardware based index and a number of pin configuration values: + +pincontroller { + ... /* Standard DT properties for the device itself elided */ + #pinctrl-cells = <2>; + + state_0_node_a { + pinctrl-pin-array = < + 0 A_DELAY_PS(0) G_DELAY_PS(120) + 4 A_DELAY_PS(0) G_DELAY_PS(360) + ... + >; + }; + ... +}; + +Above #pinctrl-cells specifies the number of value cells in addition to the +index of the registers. This is similar to the interrupts-extended binding with +one exception. There is no need to specify the phandle for each entry as that +is already known as the defined pins are always children of the pin controller +node. Further having the phandle pointing to another pin controller would not +currently work as the pinctrl framework uses named modes to group pins for each +pin control device. + +The index for pinctrl-pin-array must relate to the hardware for the pinctrl +registers, and must not be a virtual index of pin instances. The reason for +this is to avoid mapping of the index in the dts files and the pin controller +driver as it can change. + == Generic pin configuration node content == Many data items that are represented in a pin configuration node are common |