1Device tree configuration for i2c-ocores
2
3Required properties:
4- compatible      : "opencores,i2c-ocores"
5                    "aeroflexgaisler,i2cmst"
6                    "sifive,fu540-c000-i2c", "sifive,i2c0"
7                    For Opencore based I2C IP block reimplemented in
8                    FU540-C000 SoC.
9                    "sifive,fu740-c000-i2c", "sifive,i2c0"
10                    For Opencore based I2C IP block reimplemented in
11                    FU740-C000 SoC.
12                    Please refer to sifive-blocks-ip-versioning.txt for
13                    additional details.
14- reg             : bus address start and address range size of device
15- clocks          : handle to the controller clock; see the note below.
16                    Mutually exclusive with opencores,ip-clock-frequency
17- opencores,ip-clock-frequency: frequency of the controller clock in Hz;
18                    see the note below. Mutually exclusive with clocks
19- #address-cells  : should be <1>
20- #size-cells     : should be <0>
21
22Optional properties:
23- interrupts      : interrupt number.
24- clock-frequency : frequency of bus clock in Hz; see the note below.
25                    Defaults to 100 KHz when the property is not specified
26- reg-shift       : device register offsets are shifted by this value
27- reg-io-width    : io register width in bytes (1, 2 or 4)
28- regstep         : deprecated, use reg-shift above
29
30Note
31clock-frequency property is meant to control the bus frequency for i2c bus
32drivers, but it was incorrectly used to specify i2c controller input clock
33frequency. So the following rules are set to fix this situation:
34- if clock-frequency is present and neither opencores,ip-clock-frequency nor
35  clocks are, then clock-frequency specifies i2c controller clock frequency.
36  This is to keep backwards compatibility with setups using old DTB. i2c bus
37  frequency is fixed at 100 KHz.
38- if clocks is present it specifies i2c controller clock. clock-frequency
39  property specifies i2c bus frequency.
40- if opencores,ip-clock-frequency is present it specifies i2c controller
41  clock frequency. clock-frequency property specifies i2c bus frequency.
42
43Examples:
44
45	i2c0: ocores@a0000000 {
46		#address-cells = <1>;
47		#size-cells = <0>;
48		compatible = "opencores,i2c-ocores";
49		reg = <0xa0000000 0x8>;
50		interrupts = <10>;
51		opencores,ip-clock-frequency = <20000000>;
52
53		reg-shift = <0>;	/* 8 bit registers */
54		reg-io-width = <1>;	/* 8 bit read/write */
55
56		dummy@60 {
57			compatible = "dummy";
58			reg = <0x60>;
59		};
60	};
61or
62	i2c0: ocores@a0000000 {
63		#address-cells = <1>;
64		#size-cells = <0>;
65		compatible = "opencores,i2c-ocores";
66		reg = <0xa0000000 0x8>;
67		interrupts = <10>;
68		clocks = <&osc>;
69		clock-frequency = <400000>; /* i2c bus frequency 400 KHz */
70
71		reg-shift = <0>;	/* 8 bit registers */
72		reg-io-width = <1>;	/* 8 bit read/write */
73
74		dummy@60 {
75			compatible = "dummy";
76			reg = <0x60>;
77		};
78	};
79