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Thomas Chou75219d52015-12-14 20:45:08 +08001* Synopsys DesignWare ABP UART
2
3Required properties:
4- compatible : "snps,dw-apb-uart"
5- reg : offset and length of the register set for the device.
6- interrupts : should contain uart interrupt.
7
8Clock handling:
9The clock rate of the input clock needs to be supplied by one of
10- clock-frequency : the input clock frequency for the UART.
11- clocks : phandle to the input clock
12
13The supplying peripheral clock can also be handled, needing a second property
14- clock-names: tuple listing input clock names.
15 Required elements: "baudclk", "apb_pclk"
16
17Optional properties:
18- snps,uart-16550-compatible : reflects the value of UART_16550_COMPATIBLE
19 configuration parameter. Define this if your UART does not implement the busy
20 functionality.
21- resets : phandle to the parent reset controller.
22- reg-shift : quantity to shift the register offsets by. If this property is
23 not present then the register offsets are not shifted.
24- reg-io-width : the size (in bytes) of the IO accesses that should be
25 performed on the device. If this property is not present then single byte
26 accesses are used.
27- dcd-override : Override the DCD modem status signal. This signal will always
28 be reported as active instead of being obtained from the modem status
29 register. Define this if your serial port does not use this pin.
30- dsr-override : Override the DTS modem status signal. This signal will always
31 be reported as active instead of being obtained from the modem status
32 register. Define this if your serial port does not use this pin.
33- cts-override : Override the CTS modem status signal. This signal will always
34 be reported as active instead of being obtained from the modem status
35 register. Define this if your serial port does not use this pin.
36- ri-override : Override the RI modem status signal. This signal will always be
37 reported as inactive instead of being obtained from the modem status register.
38 Define this if your serial port does not use this pin.
39
40Example:
41
42 uart@80230000 {
43 compatible = "snps,dw-apb-uart";
44 reg = <0x80230000 0x100>;
45 clock-frequency = <3686400>;
46 interrupts = <10>;
47 reg-shift = <2>;
48 reg-io-width = <4>;
49 dcd-override;
50 dsr-override;
51 cts-override;
52 ri-override;
53 };
54
55Example with one clock:
56
57 uart@80230000 {
58 compatible = "snps,dw-apb-uart";
59 reg = <0x80230000 0x100>;
60 clocks = <&baudclk>;
61 interrupts = <10>;
62 reg-shift = <2>;
63 reg-io-width = <4>;
64 };
65
66Example with two clocks:
67
68 uart@80230000 {
69 compatible = "snps,dw-apb-uart";
70 reg = <0x80230000 0x100>;
71 clocks = <&baudclk>, <&apb_pclk>;
72 clock-names = "baudclk", "apb_pclk";
73 interrupts = <10>;
74 reg-shift = <2>;
75 reg-io-width = <4>;
76 };