mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-27 09:36:57 +07:00
48c926cd34
Improve the binding example by removing all the leading zeros to fix the following dtc warnings: Warning (unit_address_format): Node /XXX unit name should not have leading 0s Converted using the following command: perl -p -i -e 's/\@0+([0-9a-f])/\@$1/g' `find ./Documentation/devicetree/bindings "*.txt"` Some unnecessary changes were manually fixed. Signed-off-by: Marco Franchi <marco.franchi@nxp.com> Signed-off-by: Rob Herring <robh@kernel.org>
71 lines
2.5 KiB
Plaintext
71 lines
2.5 KiB
Plaintext
ARM System Controller ICST clocks
|
|
|
|
The ICS525 and ICS307 oscillators are produced by Integrated Devices
|
|
Technology (IDT). ARM integrated these oscillators deeply into their
|
|
reference designs by adding special control registers that manage such
|
|
oscillators to their system controllers.
|
|
|
|
The various ARM system controllers contain logic to serialize and initialize
|
|
an ICST clock request after a write to the 32 bit register at an offset
|
|
into the system controller. Furthermore, to even be able to alter one of
|
|
these frequencies, the system controller must first be unlocked by
|
|
writing a special token to another offset in the system controller.
|
|
|
|
Some ARM hardware contain special versions of the serial interface that only
|
|
connects the low 8 bits of the VDW (missing one bit), hardwires RDW to
|
|
different values and sometimes also hardwire the output divider. They
|
|
therefore have special compatible strings as per this table (the OD value is
|
|
the value on the pins, not the resulting output divider):
|
|
|
|
Hardware variant: RDW OD VDW
|
|
|
|
Integrator/AP 22 1 Bit 8 0, rest variable
|
|
integratorap-cm
|
|
|
|
Integrator/AP 46 3 Bit 8 0, rest variable
|
|
integratorap-sys
|
|
|
|
Integrator/AP 22 or 1 17 or (33 or 25 MHz)
|
|
integratorap-pci 14 1 14
|
|
|
|
Integrator/CP 22 variable Bit 8 0, rest variable
|
|
integratorcp-cm-core
|
|
|
|
Integrator/CP 22 variable Bit 8 0, rest variable
|
|
integratorcp-cm-mem
|
|
|
|
The ICST oscillator must be provided inside a system controller node.
|
|
|
|
Required properties:
|
|
- compatible: must be one of
|
|
"arm,syscon-icst525"
|
|
"arm,syscon-icst307"
|
|
"arm,syscon-icst525-integratorap-cm"
|
|
"arm,syscon-icst525-integratorap-sys"
|
|
"arm,syscon-icst525-integratorap-pci"
|
|
"arm,syscon-icst525-integratorcp-cm-core"
|
|
"arm,syscon-icst525-integratorcp-cm-mem"
|
|
- lock-offset: the offset address into the system controller where the
|
|
unlocking register is located
|
|
- vco-offset: the offset address into the system controller where the
|
|
ICST control register is located (even 32 bit address)
|
|
- #clock-cells: must be <0>
|
|
- clocks: parent clock, since the ICST needs a parent clock to derive its
|
|
frequency from, this attribute is compulsory.
|
|
|
|
Example:
|
|
|
|
syscon: syscon@10000000 {
|
|
compatible = "syscon";
|
|
reg = <0x10000000 0x1000>;
|
|
|
|
oscclk0: osc0@c {
|
|
compatible = "arm,syscon-icst307";
|
|
#clock-cells = <0>;
|
|
lock-offset = <0x20>;
|
|
vco-offset = <0x0c>;
|
|
clocks = <&xtal24mhz>;
|
|
};
|
|
(...)
|
|
};
|