1 Intersil ISL12057 I2C RTC/Alarm chip
2
3 ISL12057 is a trivial I2C device (it has simpl
4 consisting of a compatible field, an address a
5 line).
6
7 Nonetheless, it also supports an option boolea
8 ("wakeup-source") to handle the specific use-c
9 on at least three in-tree users of the chip (N
10 and 2120 ARM-based NAS); On those devices, the
11 (associated with the alarm supported by the dr
12 to the SoC but to a PMIC. It allows the device
13 RTC alarm rings. In order to mark the device h
14 get access to the 'wakealarm' sysfs entry, thi
15 be set when the IRQ#2 pin of the chip is not c
16 can wake up the device.
17
18 Required properties supported by the device:
19
20 - "compatible": must be "isil,isl12057"
21 - "reg": I2C bus address of the device
22
23 Optional properties:
24
25 - "wakeup-source": mark the chip as a wakeup
26 the availability of an IRQ line connected
27
28
29 Example isl12057 node without IRQ#2 pin connec
30
31 isl12057: isl12057@68 {
32 compatible = "isil,isl12057";
33 reg = <0x68>;
34 };
35
36
37 Example isl12057 node with IRQ#2 pin connected
38 that the pinctrl-related properties below are
39 may not be required or may be different depend
40 SoC, and the main function of the MPP used as
41 "interrupt-parent" and "interrupts" are usuall
42
43 pinctrl {
44 ...
45
46 rtc_alarm_pin:
47 marvel
48 marvel
49 };
50
51 ...
52
53 };
54
55 ...
56
57 isl12057: isl12057@68 {
58 compatible = "isil,isl12057";
59 reg = <0x68>;
60 pinctrl-0 = <&rtc_alarm_pin>;
61 pinctrl-names = "default";
62 interrupt-parent = <&gpio0>;
63 interrupts = <6 IRQ_TYPE_EDGE_
64 };
65
66
67 Example isl12057 node without IRQ#2 pin connec
68 PMIC, allowing the device to be started based
69
70 isl12057: isl12057@68 {
71 compatible = "isil,isl12057";
72 reg = <0x68>;
73 wakeup-source;
74 };
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