TI SysCon Reset Controller ======================= Almost all SoCs have hardware modules that require reset control in addition to clock and power control for their functionality. The reset control is typically provided by means of memory-mapped I/O registers. These registers are sometimes a part of a larger register space region implementing various functionalities. This register range is best represented as a syscon node to allow multiple entities to access their relevant registers in the common register space. A SysCon Reset Controller node defines a device that uses a syscon node and provides reset management functionality for various hardware modules present on the SoC. SysCon Reset Controller Node ============================ Each of the reset provider/controller nodes should be a child of a syscon node and have the following properties. Required properties: -------------------- - compatible : Should be, "ti,k2e-pscrst" "ti,k2l-pscrst" "ti,k2hk-pscrst" "ti,syscon-reset" - #reset-cells : Should be 1. Please see the reset consumer node below for usage details - ti,reset-bits : Contains the reset control register information Should contain 7 cells for each reset exposed to consumers, defined as: Cell #1 : offset of the reset assert control register from the syscon register base Cell #2 : bit position of the reset in the reset assert control register Cell #3 : offset of the reset deassert control register from the syscon register base Cell #4 : bit position of the reset in the reset deassert control register Cell #5 : offset of the reset status register from the syscon register base Cell #6 : bit position of the reset in the reset status register Cell #7 : Flags used to control reset behavior, available flags defined in the DT include file <dt-bindings/reset/ti-syscon.h> SysCon Reset Consumer Nodes =========================== Each of the reset consumer nodes should have the following properties, in addition to their own properties. Required properties: -------------------- - resets : A phandle to the reset controller node and an index number to a reset specifier as defined above. Please also refer to Documentation/devicetree/bindings/reset/reset.txt for common reset controller usage by consumers. Example: -------- The following example demonstrates a syscon node, the reset controller node using the syscon node, and a consumer (a DSP device) on the TI Keystone 2 66AK2E SoC. / { soc { psc: power-sleep-controller@2350000 { compatible = "syscon", "simple-mfd"; reg = <0x02350000 0x1000>; pscrst: reset-controller { compatible = "ti,k2e-pscrst", "ti,syscon-reset"; #reset-cells = <1>; ti,reset-bits = < 0xa3c 8 0xa3c 8 0x83c 8 (ASSERT_CLEAR | DEASSERT_SET | STATUS_CLEAR) /* 0: dsp0 */ 0xa40 5 0xa44 3 0 0 (ASSERT_SET | DEASSERT_CLEAR | STATUS_NONE) /* 1: example */ >; }; }; dsp0: dsp0 { ... resets = <&pscrst 0>; ... }; }; };