[mirror_ubuntu-bionic-kernel.git] / Documentation / devicetree / bindings / reset / st,sti-powerdown.txt

STMicroelectronics STi family Sysconfig Peripheral Powerdown Reset Controller
=============================================================================

This binding describes a reset controller device that is used to enable and
disable on-chip peripheral controllers such as USB and SATA, using
"powerdown" control bits found in the STi family SoC system configuration
registers. These have been grouped together into a single reset controller
device for convenience.

The actual action taken when powerdown is asserted is hardware dependent.
However, when asserted it may not be possible to access the hardware's
registers and after an assert/deassert sequence the hardware's previous state
may no longer be valid.

Please refer to reset.txt in this directory for common reset
controller binding usage.

Required properties:
- compatible: Should be "st,stih407-powerdown"
- #reset-cells: 1, see below

example:

	powerdown: powerdown-controller {
		compatible = "st,stih407-powerdown";
		#reset-cells = <1>;
	};


Specifying powerdown control of devices
=======================================

Device nodes should specify the reset channel required in their "resets"
property, containing a phandle to the powerdown device node and an
index specifying which channel to use, as described in reset.txt

example:

	st_dwc3: dwc3@8f94000 {
		resets          = <&powerdown STIH407_USB3_POWERDOWN>,
	};

Macro definitions for the supported reset channels can be found in:

include/dt-bindings/reset/stih407-resets.h
Commit	Line	Data
6b7f06cc SK	1	STMicroelectronics STi family Sysconfig Peripheral Powerdown Reset Controller
	2	=============================================================================
	3
	4	This binding describes a reset controller device that is used to enable and
	5	disable on-chip peripheral controllers such as USB and SATA, using
	6	"powerdown" control bits found in the STi family SoC system configuration
	7	registers. These have been grouped together into a single reset controller
	8	device for convenience.
	9
	10	The actual action taken when powerdown is asserted is hardware dependent.
	11	However, when asserted it may not be possible to access the hardware's
	12	registers and after an assert/deassert sequence the hardware's previous state
	13	may no longer be valid.
	14
	15	Please refer to reset.txt in this directory for common reset
	16	controller binding usage.
	17
	18	Required properties:
cbac8a08	19	- compatible: Should be "st,stih407-powerdown"
6b7f06cc SK	20	- #reset-cells: 1, see below
	21
	22	example:
	23
	24	powerdown: powerdown-controller {
cbac8a08	25	compatible = "st,stih407-powerdown";
6b7f06cc	26	#reset-cells = <1>;
6b7f06cc SK	27	};
	28
	29
	30	Specifying powerdown control of devices
	31	=======================================
	32
	33	Device nodes should specify the reset channel required in their "resets"
	34	property, containing a phandle to the powerdown device node and an
	35	index specifying which channel to use, as described in reset.txt
	36
	37	example:
	38
cbac8a08 PG	39	st_dwc3: dwc3@8f94000 {
cbac8a08 PG	40	resets = <&powerdown STIH407_USB3_POWERDOWN>,
6b7f06cc SK	41	};
	42
	43	Macro definitions for the supported reset channels can be found in:
	44
cbac8a08	45	include/dt-bindings/reset/stih407-resets.h