xref: /freebsd/sys/contrib/device-tree/Bindings/pinctrl/pinctrl-zx.txt (revision a90b9d0159070121c221b966469c3e36d912bf82) 
1* ZTE ZX Pin Controller
2
3The pin controller on ZTE ZX platforms is kinda of hybrid.  It consists of
4a main controller and an auxiliary one.  For example, on ZX296718 SoC, the
5main controller is TOP_PMM and the auxiliary one is AON_IOCFG.  Both
6controllers work together to control pin multiplexing and configuration in
7the way illustrated as below.
8
9
10           GMII_RXD3 ---+
11                        |
12             DVI1_HS ---+----------------------------- GMII_RXD3 (TOP pin)
13                        |
14             BGPIO16 ---+                               ^
15                                                        | pinconf
16                        ^                               |
17                        | pinmux                        |
18                        |                               |
19
20                   TOP_PMM (main)           AON_IOCFG (aux)
21
22                        |                       |       |
23                        |                pinmux |       |
24                        | pinmux                v       |
25                        v                               | pinconf
26                                    KEY_ROW2 ---+       v
27        PORT1_LCD_TE ---+                       |
28                        |            AGPIO10 ---+------ KEY_ROW2 (AON pin)
29          I2S0_DOUT3 ---+                       |
30                        |-----------------------+
31            PWM_OUT3 ---+
32                        |
33             VGA_VS1 ---+
34
35
36For most of pins like GMII_RXD3 in the figure, the pinmux function is
37controlled by TOP_PMM block only, and this type of pins are meant by term
38'TOP pins'.  For pins like KEY_ROW2, the pinmux is controlled by both
39TOP_PMM and AON_IOCFG blocks, as the available multiplexing functions for
40the pin spread in both controllers.  This type of pins are called 'AON pins'.
41Though pinmux implementation is quite different, pinconf is same for both
42types of pins.  Both are controlled by auxiliary controller, i.e. AON_IOCFG
43on ZX296718.
44
45Required properties:
46- compatible: should be "zte,zx296718-pmm".
47- reg: the register physical address and length.
48- zte,auxiliary-controller: phandle to the auxiliary pin controller which
49  implements pinmux for AON pins and pinconf for all pins.
50
51The following pin configuration are supported. Please refer to
52pinctrl-bindings.txt in this directory for more details of the common
53pinctrl bindings used by client devices.
54
55- bias-pull-up
56- bias-pull-down
57- drive-strength
58- input-enable
59- slew-rate
60
61Examples:
62
63iocfg: pin-controller@119000 {
64	compatible = "zte,zx296718-iocfg";
65	reg = <0x119000 0x1000>;
66};
67
68pmm: pin-controller@1462000 {
69	compatible = "zte,zx296718-pmm";
70	reg = <0x1462000 0x1000>;
71	zte,auxiliary-controller = <&iocfg>;
72};
73
74&pmm {
75	vga_pins: vga {
76		pins = "KEY_COL1", "KEY_COL2", "KEY_ROW1", "KEY_ROW2";
77		function = "VGA";
78	};
79};
80
81&vga {
82	pinctrl-names = "default";
83	pinctrl-0 = <&vga_pins>;
84};
85