1 CE4100 I2C
2 ----------
3
4 CE4100 has one PCI device which is described a
5 PCI device has three PCI-bars, each bar contai
6 controller. So we have a total of three indepe
7 which share only an interrupt line.
8 The driver is probed via the PCI-ID and is gat
9 attached devices from the devices tree.
10 Grant Likely recommended to use the ranges pro
11 number to its physical address and to use this
12 of the specific I2C controller. This were his
13
14 Here's where the magic happens. Each e
15 ranges describes how the parent pci add
16 (middle group of 3) is translated to th
17 address space (first group of 2) and th
18 each range (last cell). In this partic
19 the first cell of the local address is
20 1:1 mapped to the BARs, and the second
21 offset from be base of the BAR (which w
22 non-zero if you had 2 or more devices m
23 the same BAR)
24
25 ranges allows the address mapping to be
26 in a way that the OS can interpret with
27 requiring custom device driver code.
28
29 This is an example which is used on FalconFall
30 ----------------------------------------------
31 i2c-controller@b,2 {
32 #address-cells = <2>;
33 #size-cells = <1>;
34 compatible = "pci8086,2e68.2",
35 "pci8086,2e68"
36 "pciclass,ff00
37 "pciclass,ff00
38
39 reg = <0x15a00 0x0 0x0 0x0 0x0
40 interrupts = <16 1>;
41
42 /* as described by Grant, the
43 * three is the bar number foll
44 * followed by size of the mapp
45 * requires also a valid transl
46 * property.
47 */
48 ranges = <0 0 0x02000000 0 0
49 1 0 0x02000000 0 0
50 2 0 0x02000000 0 0
51
52 i2c@0 {
53 #address-cells = <1>;
54 #size-cells = <0>;
55 compatible = "intel,ce
56
57 /* The first number in
58 * number of the bar
59 */
60 reg = <0 0 0x100>;
61
62 /* This I2C controller
63 };
64
65 i2c@1 {
66 #address-cells = <1>;
67 #size-cells = <0>;
68 compatible = "intel,ce
69 reg = <1 0 0x100>;
70
71 /* This I2C controller
72 gpio@26 {
73 #gpio-cells =
74 compatible = "
75 reg = <0x26>;
76 gpio-controlle
77 };
78 };
79
80 i2c@2 {
81 #address-cells = <1>;
82 #size-cells = <0>;
83 compatible = "intel,ce
84 reg = <2 0 0x100>;
85
86 gpio@26 {
87 #gpio-cells =
88 compatible = "
89 reg = <0x26>;
90 gpio-controlle
91 };
92 };
93 };
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