--- zzzz-none-000/linux-3.10.107/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt	2021-02-04 17:41:59.000000000 +0000
@@ -38,7 +38,7 @@
 assigned a name. When names are used, another property exists to map from
 those names to the integer IDs.
 
-Each client device's own binding determines the set of states the must be
+Each client device's own binding determines the set of states that must be
 defined in its device tree node, and whether to define the set of state
 IDs that must be provided, or whether to define the set of state names that
 must be provided.
@@ -126,3 +126,111 @@
 whether there is any interaction between the child and intermediate parent
 nodes, is again defined entirely by the binding for the individual pin
 controller device.
+
+== Generic pin multiplexing node content ==
+
+pin multiplexing nodes:
+
+function		- the mux function to select
+groups			- the list of groups to select with this function
+			  (either this or "pins" must be specified)
+pins			- the list of pins to select with this function (either
+			  this or "groups" must be specified)
+
+Example:
+
+state_0_node_a {
+	uart0 {
+		function = "uart0";
+		groups = "u0rxtx", "u0rtscts";
+	};
+};
+state_1_node_a {
+	spi0 {
+		function = "spi0";
+		groups = "spi0pins";
+	};
+};
+state_2_node_a {
+	function = "i2c0";
+	pins = "mfio29", "mfio30";
+};
+
+== Generic pin configuration node content ==
+
+Many data items that are represented in a pin configuration node are common
+and generic. Pin control bindings should use the properties defined below
+where they are applicable; not all of these properties are relevant or useful
+for all hardware or binding structures. Each individual binding document
+should state which of these generic properties, if any, are used, and the
+structure of the DT nodes that contain these properties.
+
+Supported generic properties are:
+
+pins			- the list of pins that properties in the node
+			  apply to (either this or "group" has to be
+			  specified)
+group			- the group to apply the properties to, if the driver
+			  supports configuration of whole groups rather than
+			  individual pins (either this or "pins" has to be
+			  specified)
+bias-disable		- disable any pin bias
+bias-high-impedance	- high impedance mode ("third-state", "floating")
+bias-bus-hold		- latch weakly
+bias-pull-up		- pull up the pin
+bias-pull-down		- pull down the pin
+bias-pull-pin-default	- use pin-default pull state
+drive-push-pull		- drive actively high and low
+drive-open-drain	- drive with open drain
+drive-open-source	- drive with open source
+drive-strength		- sink or source at most X mA
+input-enable		- enable input on pin (no effect on output)
+input-disable		- disable input on pin (no effect on output)
+input-schmitt-enable	- enable schmitt-trigger mode
+input-schmitt-disable	- disable schmitt-trigger mode
+input-debounce		- debounce mode with debound time X
+power-source		- select between different power supplies
+low-power-enable	- enable low power mode
+low-power-disable	- disable low power mode
+output-low		- set the pin to output mode with low level
+output-high		- set the pin to output mode with high level
+slew-rate		- set the slew rate
+
+For example:
+
+state_0_node_a {
+	cts_rxd {
+		pins = "GPIO0_AJ5", "GPIO2_AH4"; /* CTS+RXD */
+		bias-pull-up;
+	};
+};
+state_1_node_a {
+	rts_txd {
+		pins = "GPIO1_AJ3", "GPIO3_AH3"; /* RTS+TXD */
+		output-high;
+	};
+};
+state_2_node_a {
+	foo {
+		group = "foo-group";
+		bias-pull-up;
+	};
+};
+
+Some of the generic properties take arguments. For those that do, the
+arguments are described below.
+
+- pins takes a list of pin names or IDs as a required argument. The specific
+  binding for the hardware defines:
+  - Whether the entries are integers or strings, and their meaning.
+
+- bias-pull-up, -down and -pin-default take as optional argument on hardware
+  supporting it the pull strength in Ohm. bias-disable will disable the pull.
+
+- drive-strength takes as argument the target strength in mA.
+
+- input-debounce takes the debounce time in usec as argument
+  or 0 to disable debouncing
+
+More in-depth documentation on these parameters can be found in
+<include/linux/pinctrl/pinconf-generic.h>