device-tree-bindings/pinctrl/pinctrl-bindings.txt

3 Hardware modules that control pin multiplexing or configuration parameters
4 such as pull-up/down, tri-state, drive-strength etc are designated as pin
5 controllers. Each pin controller must be represented as a node in device tree,
8 Hardware modules whose signals are affected by pin configuration are
12 For a client device to operate correctly, certain pin controllers must
13 set up certain specific pin configurations. Some client devices need a
14 single static pin configuration, e.g. set up during initialization. Others
15 need to reconfigure pins at run-time, for example to tri-state pins when the
21 for client device device tree nodes to map those state names to the pin
24 Note that pin controllers themselves may also be client devices of themselves.
25 For example, a pin controller may set up its own "active" state when the
26 driver loads. This would allow representing a board's static pin configuration
31 they require certain specific named states for dynamic pin configuration.
35 For each client device individually, every pin state is assigned an integer
37 property exists to define the pin configuration. Each state may also be
47 pinctrl-0:	List of phandles, each pointing at a pin configuration
48 		node. These referenced pin configuration nodes must be child
49 		nodes of the pin controller that they configure. Multiple
50 		entries may exist in this list so that multiple pin
52 		from multiple nodes for a single pin controller, each
55 		pin configuration nodes.
59 		used in an SoC either without a pin controller, or where the
60 		pin controller does not affect the HW module in question. If
61 		the binding for that IP block requires certain pin states to
65 pinctrl-1:	List of phandles, each pointing at a pin configuration
66 		node within a pin controller.
68 pinctrl-n:	List of phandles, each pointing at a pin configuration
69 		node within a pin controller.
70 pinctrl-names:	The list of names to assign states. List entry 0 defines the
78 		pinctrl-names = "active", "idle";
79 		pinctrl-0 = <&state_0_node_a>;
80 		pinctrl-1 = <&state_1_node_a &state_1_node_b>;
85 		pinctrl-0 = <&state_0_node_a>;
86 		pinctrl-1 = <&state_1_node_a &state_1_node_b>;
90 	 * For an IP block whose binding supports pin configuration,
91 	 * but in use on an SoC that doesn't have any pin control hardware
94 		pinctrl-names = "active", "idle";
95 		pinctrl-0 = <>;
96 		pinctrl-1 = <>;
99 == Pin controller devices ==
101 Pin controller devices should contain the pin configuration nodes that client
120 The contents of each of those pin configuration child nodes is defined
121 entirely by the binding for the individual pin controller device. There
124 The pin configuration nodes need not be direct children of the pin controller
127 nodes, is again defined entirely by the binding for the individual pin
130 == Generic pin multiplexing node content ==
132 pin multiplexing nodes:
134 function		- the mux function to select
135 groups			- the list of groups to select with this function
137 pins			- the list of pins to select with this function (either
159 == Generic pin configuration node content ==
161 Many data items that are represented in a pin configuration node are common
162 and generic. Pin control bindings should use the properties defined below
170 pins			- the list of pins that properties in the node
173 group			- the group to apply the properties to, if the driver
177 bias-disable		- disable any pin bias
178 bias-high-impedance	- high impedance mode ("third-state", "floating")
179 bias-bus-hold		- latch weakly
180 bias-pull-up		- pull up the pin
181 bias-pull-down		- pull down the pin
182 bias-pull-pin-default	- use pin-default pull state
183 drive-push-pull		- drive actively high and low
184 drive-open-drain	- drive with open drain
185 drive-open-source	- drive with open source
186 drive-strength		- sink or source at most X mA
187 input-enable		- enable input on pin (no effect on output)
188 input-disable		- disable input on pin (no effect on output)
189 input-schmitt-enable	- enable schmitt-trigger mode
190 input-schmitt-disable	- disable schmitt-trigger mode
191 input-debounce		- debounce mode with debound time X
192 power-source		- select between different power supplies
193 low-power-enable	- enable low power mode
194 low-power-disable	- disable low power mode
195 output-low		- set the pin to output mode with low level
196 output-high		- set the pin to output mode with high level
197 slew-rate		- set the slew rate
204 		bias-pull-up;
210 		output-high;
215 		group = "foo-group";
216 		bias-pull-up;
223 - pins takes a list of pin names or IDs as a required argument. The specific
225   - Whether the entries are integers or strings, and their meaning.
227 - bias-pull-up, -down and -pin-default take as optional argument on hardware
228   supporting it the pull strength in Ohm. bias-disable will disable the pull.
230 - drive-strength takes as argument the target strength in mA.
232 - input-debounce takes the debounce time in usec as argument
235 More in-depth documentation on these parameters can be found in
236 <include/linux/pinctrl/pinconf-generic.h>