diff options
Diffstat (limited to 'doc/device-tree-bindings')
-rw-r--r-- | doc/device-tree-bindings/bus/simple-pm-bus.txt | 44 | ||||
-rw-r--r-- | doc/device-tree-bindings/mfd/kendryte,k210-sysctl.txt | 33 | ||||
-rw-r--r-- | doc/device-tree-bindings/reset/syscon-reset.txt | 36 |
3 files changed, 113 insertions, 0 deletions
diff --git a/doc/device-tree-bindings/bus/simple-pm-bus.txt b/doc/device-tree-bindings/bus/simple-pm-bus.txt new file mode 100644 index 0000000000..6f15037131 --- /dev/null +++ b/doc/device-tree-bindings/bus/simple-pm-bus.txt @@ -0,0 +1,44 @@ +Simple Power-Managed Bus +======================== + +A Simple Power-Managed Bus is a transparent bus that doesn't need a real +driver, as it's typically initialized by the boot loader. + +However, its bus controller is part of a PM domain, or under the control of a +functional clock. Hence, the bus controller's PM domain and/or clock must be +enabled for child devices connected to the bus (either on-SoC or externally) +to function. + +While "simple-pm-bus" follows the "simple-bus" set of properties, as specified +in the Devicetree Specification, it is not an extension of "simple-bus". + + +Required properties: + - compatible: Must contain at least "simple-pm-bus". + Must not contain "simple-bus". + It's recommended to let this be preceded by one or more + vendor-specific compatible values. + - #address-cells, #size-cells, ranges: Must describe the mapping between + parent address and child address spaces. + +Optional platform-specific properties for clock or PM domain control (at least +one of them is required): + - clocks: Must contain a reference to the functional clock(s), + - power-domains: Must contain a reference to the PM domain. +Please refer to the binding documentation for the clock and/or PM domain +providers for more details. + + +Example: + + bsc: bus@fec10000 { + compatible = "renesas,bsc-sh73a0", "renesas,bsc", + "simple-pm-bus"; + #address-cells = <1>; + #size-cells = <1>; + ranges = <0 0 0x20000000>; + reg = <0xfec10000 0x400>; + interrupts = <0 39 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&zb_clk>; + power-domains = <&pd_a4s>; + }; diff --git a/doc/device-tree-bindings/mfd/kendryte,k210-sysctl.txt b/doc/device-tree-bindings/mfd/kendryte,k210-sysctl.txt new file mode 100644 index 0000000000..5b24abcb62 --- /dev/null +++ b/doc/device-tree-bindings/mfd/kendryte,k210-sysctl.txt @@ -0,0 +1,33 @@ +Kendryte K210 Sysctl + +This binding describes the K210 sysctl device, which contains many miscellaneous +registers controlling system functionality. This node is a register map and can +be reference by other bindings which need a phandle to the K210 sysctl regmap. + +Required properties: +- compatible: should be + "kendryte,k210-sysctl", "syscon", "simple-mfd" +- reg: address and length of the sysctl registers +- reg-io-width: must be <4> + +Clock sub-node + +This node is a binding for the clock tree driver + +Required properties: +- compatible: should be "kendryte,k210-clk" +- clocks: phandle to the "in0" external oscillator +- #clock-cells: must be <1> + +Example: +sysctl: syscon@50440000 { + compatible = "kendryte,k210-sysctl", "syscon", "simple-mfd"; + reg = <0x50440000 0x100>; + reg-io-width = <4>; + + sysclk: clock-controller { + compatible = "kendryte,k210-clk"; + clocks = <&in0>; + #clock-cells = <1>; + }; +}; diff --git a/doc/device-tree-bindings/reset/syscon-reset.txt b/doc/device-tree-bindings/reset/syscon-reset.txt new file mode 100644 index 0000000000..f136b3d225 --- /dev/null +++ b/doc/device-tree-bindings/reset/syscon-reset.txt @@ -0,0 +1,36 @@ +Generic SYSCON mapped register reset driver + +This is a generic reset driver using syscon to map the reset register. +The reset is generally performed with a write to the reset register +defined by the register map pointed by syscon reference plus the offset and +shifted by the reset specifier/ + +To assert a reset on some device, the equivalent of the following operation is +performed, where reset_id is the reset specifier from the device's resets +property. + + if (BIT(reset_id) & mask) + regmap[offset][reset_id] = assert-high; + +Required properties: +- compatible: should contain "syscon-reset" +- #reset-cells: must be 1 +- regmap: this is phandle to the register map node +- offset: offset in the register map for the reboot register (in bytes) + +Optional properties: +- mask: accept only the reset specifiers defined by the mask (32 bit) +- assert-high: Bit to write when asserting a reset. Defaults to 1. + +Default will be little endian mode, 32 bit access only. + +Example: + + reset-controller { + compatible = "syscon-reset"; + #reset-cells = <1>; + regmap = <&sysctl>; + offset = <0x20>; + mask = <0x27FFFFFF>; + assert-high = <0>; + }; |