[deliverable/linux.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,<chip>-powerdown"
	ex: "st,stih415-powerdown", "st,stih416-powerdown"
- #reset-cells: 1, see below

example:

	powerdown: powerdown-controller {
		#reset-cells = <1>;
		compatible = "st,stih415-powerdown";
	};


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:

	usb1: usb@fe200000 {
		resets	= <&powerdown STIH41X_USB1_POWERDOWN>;
	};

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

include/dt-bindings/reset/stih415-resets.h
include/dt-bindings/reset/stih416-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:
	19	- compatible: Should be "st,<chip>-powerdown"
	20	ex: "st,stih415-powerdown", "st,stih416-powerdown"
	21	- #reset-cells: 1, see below
	22
	23	example:
	24
	25	powerdown: powerdown-controller {
	26	#reset-cells = <1>;
	27	compatible = "st,stih415-powerdown";
	28	};
	29
	30
	31	Specifying powerdown control of devices
	32	=======================================
	33
	34	Device nodes should specify the reset channel required in their "resets"
	35	property, containing a phandle to the powerdown device node and an
	36	index specifying which channel to use, as described in reset.txt
	37
	38	example:
	39
	40	usb1: usb@fe200000 {
	41	resets = <&powerdown STIH41X_USB1_POWERDOWN>;
	42	};
	43
	44	Macro definitions for the supported reset channels can be found in:
	45
efdf5aa8 PZ	46	include/dt-bindings/reset/stih415-resets.h
efdf5aa8 PZ	47	include/dt-bindings/reset/stih416-resets.h