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
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.
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
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
123 provides generic helper bindings that the pin controller driver can use.
125 The pin configuration nodes need not be direct children of the pin controller
128 nodes, is again defined entirely by the binding for the individual pin
131 == Generic pin multiplexing node content ==
133 pin multiplexing nodes:
160 For hardware where pin multiplexing configurations have to be specified for
161 each single pin the number of required sub-nodes containing "pin" and
165 For cases like this, the pin controller driver may use the pinmux helper
166 property, where the pin identifier is provided with mux configuration settings
167 in a pinmux group. A pinmux group consists of the pin identifier and mux
171 a single pin multiplexing configuration.
179 Each individual pin controller driver bindings documentation shall specify
180 how pin IDs and pin multiplexing configuration are defined and assembled
183 == Generic pin configuration node content ==
185 Many data items that are represented in a pin configuration node are common
201 pinmux			- the list of numeric pin ids and their mux settings
204 bias-disable		- disable any pin bias
207 bias-pull-up		- pull up the pin
208 bias-pull-down		- pull down the pin
209 bias-pull-pin-default	- use pin-default pull state
215 input-enable		- enable input on pin (no effect on output, such as
217 input-disable		- disable input on pin (no effect on output, such as
225 output-disable		- disable output on a pin (such as disable an output
227 output-enable		- enable output on a pin without actively driving it
229 output-low		- set the pin to output mode with low level
230 output-high		- set the pin to output mode with high level
236 			  pin. Typically indicates how many double-inverters are
269 - pins takes a list of pin names or IDs as a required argument. The specific
273 - pinmux takes a list of pin IDs and mux settings as required argument. The
275   - How pin IDs and mux settings are defined and assembled together in a single
278 - bias-pull-up, -down and -pin-default take as optional argument on hardware