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Diffstat (limited to 'Documentation/devicetree/bindings/c6x/dscr.txt')
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diff --git a/Documentation/devicetree/bindings/c6x/dscr.txt b/Documentation/devicetree/bindings/c6x/dscr.txt new file mode 100644 index 000000000000..d847758f2b20 --- /dev/null +++ b/Documentation/devicetree/bindings/c6x/dscr.txt @@ -0,0 +1,127 @@ +Device State Configuration Registers +------------------------------------ + +TI C6X SoCs contain a region of miscellaneous registers which provide various +function for SoC control or status. Details vary considerably among from SoC +to SoC with no two being alike. + +In general, the Device State Configuraion Registers (DSCR) will provide one or +more configuration registers often protected by a lock register where one or +more key values must be written to a lock register in order to unlock the +configuration register for writes. These configuration register may be used to +enable (and disable in some cases) SoC pin drivers, select peripheral clock +sources (internal or pin), etc. In some cases, a configuration register is +write once or the individual bits are write once. In addition to device config, +the DSCR block may provide registers which which are used to reset peripherals, +provide device ID information, provide ethernet MAC addresses, as well as other +miscellaneous functions. + +For device state control (enable/disable), each device control is assigned an +id which is used by individual device drivers to control the state as needed. + +Required properties: + +- compatible: must be "ti,c64x+dscr" +- reg: register area base and size + +Optional properties: + + NOTE: These are optional in that not all SoCs will have all properties. For + SoCs which do support a given property, leaving the property out of the + device tree will result in reduced functionality or possibly driver + failure. + +- ti,dscr-devstat + offset of the devstat register + +- ti,dscr-silicon-rev + offset, start bit, and bitsize of silicon revision field + +- ti,dscr-rmii-resets + offset and bitmask of RMII reset field. May have multiple tuples if more + than one ethernet port is available. + +- ti,dscr-locked-regs + possibly multiple tuples describing registers which are write protected by + a lock register. Each tuple consists of the register offset, lock register + offsset, and the key value used to unlock the register. + +- ti,dscr-kick-regs + offset and key values of two "kick" registers used to write protect other + registers in DSCR. On SoCs using kick registers, the first key must be + written to the first kick register and the second key must be written to + the second register before other registers in the area are write-enabled. + +- ti,dscr-mac-fuse-regs + MAC addresses are contained in two registers. Each element of a MAC address + is contained in a single byte. This property has two tuples. Each tuple has + a register offset and four cells representing bytes in the register from + most significant to least. The value of these four cells is the MAC byte + index (1-6) of the byte within the register. A value of 0 means the byte + is unused in the MAC address. + +- ti,dscr-devstate-ctl-regs + This property describes the bitfields used to control the state of devices. + Each tuple describes a range of identical bitfields used to control one or + more devices (one bitfield per device). The layout of each tuple is: + + start_id num_ids reg enable disable start_bit nbits + + Where: + start_id is device id for the first device control in the range + num_ids is the number of device controls in the range + reg is the offset of the register holding the control bits + enable is the value to enable a device + disable is the value to disable a device (0xffffffff if cannot disable) + start_bit is the bit number of the first bit in the range + nbits is the number of bits per device control + +- ti,dscr-devstate-stat-regs + This property describes the bitfields used to provide device state status + for device states controlled by the DSCR. Each tuple describes a range of + identical bitfields used to provide status for one or more devices (one + bitfield per device). The layout of each tuple is: + + start_id num_ids reg enable disable start_bit nbits + + Where: + start_id is device id for the first device status in the range + num_ids is the number of devices covered by the range + reg is the offset of the register holding the status bits + enable is the value indicating device is enabled + disable is the value indicating device is disabled + start_bit is the bit number of the first bit in the range + nbits is the number of bits per device status + +- ti,dscr-privperm + Offset and default value for register used to set access privilege for + some SoC devices. + + +Example: + + device-state-config-regs@2a80000 { + compatible = "ti,c64x+dscr"; + reg = <0x02a80000 0x41000>; + + ti,dscr-devstat = <0>; + ti,dscr-silicon-rev = <8 28 0xf>; + ti,dscr-rmii-resets = <0x40020 0x00040000>; + + ti,dscr-locked-regs = <0x40008 0x40004 0x0f0a0b00>; + ti,dscr-devstate-ctl-regs = + <0 12 0x40008 1 0 0 2 + 12 1 0x40008 3 0 30 2 + 13 2 0x4002c 1 0xffffffff 0 1>; + ti,dscr-devstate-stat-regs = + <0 10 0x40014 1 0 0 3 + 10 2 0x40018 1 0 0 3>; + + ti,dscr-mac-fuse-regs = <0x700 1 2 3 4 + 0x704 5 6 0 0>; + + ti,dscr-privperm = <0x41c 0xaaaaaaaa>; + + ti,dscr-kick-regs = <0x38 0x83E70B13 + 0x3c 0x95A4F1E0>; + }; |