mirror of https://gitee.com/openkylin/linux.git
79 lines
2.3 KiB
Plaintext
79 lines
2.3 KiB
Plaintext
Intersil ISL12057 I2C RTC/Alarm chip
|
|
|
|
ISL12057 is a trivial I2C device (it has simple device tree bindings,
|
|
consisting of a compatible field, an address and possibly an interrupt
|
|
line).
|
|
|
|
Nonetheless, it also supports an option boolean property
|
|
("isil,irq2-can-wakeup-machine") to handle the specific use-case found
|
|
on at least three in-tree users of the chip (NETGEAR ReadyNAS 102, 104
|
|
and 2120 ARM-based NAS); On those devices, the IRQ#2 pin of the chip
|
|
(associated with the alarm supported by the driver) is not connected
|
|
to the SoC but to a PMIC. It allows the device to be powered up when
|
|
RTC alarm rings. In order to mark the device has a wakeup source and
|
|
get access to the 'wakealarm' sysfs entry, this specific property can
|
|
be set when the IRQ#2 pin of the chip is not connected to the SoC but
|
|
can wake up the device.
|
|
|
|
Required properties supported by the device:
|
|
|
|
- "compatible": must be "isil,isl12057"
|
|
- "reg": I2C bus address of the device
|
|
|
|
Optional properties:
|
|
|
|
- "isil,irq2-can-wakeup-machine": mark the chip as a wakeup source,
|
|
independently of the availability of an IRQ line connected to the
|
|
SoC.
|
|
|
|
- "interrupt-parent", "interrupts": for passing the interrupt line
|
|
of the SoC connected to IRQ#2 of the RTC chip.
|
|
|
|
|
|
Example isl12057 node without IRQ#2 pin connected (no alarm support):
|
|
|
|
isl12057: isl12057@68 {
|
|
compatible = "isil,isl12057";
|
|
reg = <0x68>;
|
|
};
|
|
|
|
|
|
Example isl12057 node with IRQ#2 pin connected to main SoC via MPP6 (note
|
|
that the pinctrl-related properties below are given for completeness and
|
|
may not be required or may be different depending on your system or
|
|
SoC, and the main function of the MPP used as IRQ line, i.e.
|
|
"interrupt-parent" and "interrupts" are usually sufficient):
|
|
|
|
pinctrl {
|
|
...
|
|
|
|
rtc_alarm_pin: rtc_alarm_pin {
|
|
marvell,pins = "mpp6";
|
|
marvell,function = "gpio";
|
|
};
|
|
|
|
...
|
|
|
|
};
|
|
|
|
...
|
|
|
|
isl12057: isl12057@68 {
|
|
compatible = "isil,isl12057";
|
|
reg = <0x68>;
|
|
pinctrl-0 = <&rtc_alarm_pin>;
|
|
pinctrl-names = "default";
|
|
interrupt-parent = <&gpio0>;
|
|
interrupts = <6 IRQ_TYPE_EDGE_FALLING>;
|
|
};
|
|
|
|
|
|
Example isl12057 node without IRQ#2 pin connected to the SoC but to a
|
|
PMIC, allowing the device to be started based on configured alarm:
|
|
|
|
isl12057: isl12057@68 {
|
|
compatible = "isil,isl12057";
|
|
reg = <0x68>;
|
|
isil,irq2-can-wakeup-machine;
|
|
};
|