xref: /freebsd/sys/contrib/device-tree/Bindings/pwm/nvidia,tegra20-pwm.txt (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71) 
1Tegra SoC PWFM controller
2
3Required properties:
4- compatible: Must be:
5  - "nvidia,tegra20-pwm": for Tegra20
6  - "nvidia,tegra30-pwm", "nvidia,tegra20-pwm": for Tegra30
7  - "nvidia,tegra114-pwm", "nvidia,tegra20-pwm": for Tegra114
8  - "nvidia,tegra124-pwm", "nvidia,tegra20-pwm": for Tegra124
9  - "nvidia,tegra132-pwm", "nvidia,tegra20-pwm": for Tegra132
10  - "nvidia,tegra210-pwm", "nvidia,tegra20-pwm": for Tegra210
11  - "nvidia,tegra186-pwm": for Tegra186
12  - "nvidia,tegra194-pwm": for Tegra194
13- reg: physical base address and length of the controller's registers
14- #pwm-cells: should be 2. See pwm.yaml in this directory for a description of
15  the cells format.
16- clocks: Must contain one entry, for the module clock.
17  See ../clocks/clock-bindings.txt for details.
18- resets: Must contain an entry for each entry in reset-names.
19  See ../reset/reset.txt for details.
20- reset-names: Must include the following entries:
21  - pwm
22
23Optional properties:
24============================
25In some of the interface like PWM based regulator device, it is required
26to configure the pins differently in different states, especially in suspend
27state of the system. The configuration of pin is provided via the pinctrl
28DT node as detailed in the pinctrl DT binding document
29	Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
30
31The PWM node will have following optional properties.
32pinctrl-names:	Pin state names. Must be "default" and "sleep".
33pinctrl-0:	phandle for the default/active state of pin configurations.
34pinctrl-1:	phandle for the sleep state of pin configurations.
35
36Example:
37
38	pwm: pwm@7000a000 {
39		compatible = "nvidia,tegra20-pwm";
40		reg = <0x7000a000 0x100>;
41		#pwm-cells = <2>;
42		clocks = <&tegra_car 17>;
43		resets = <&tegra_car 17>;
44		reset-names = "pwm";
45	};
46
47
48Example with the pin configuration for suspend and resume:
49=========================================================
50Suppose pin PE7 (On Tegra210) interfaced with the regulator device and
51it requires PWM output to be tristated when system enters suspend.
52Following will be DT binding to achieve this:
53
54#include <dt-bindings/pinctrl/pinctrl-tegra.h>
55
56	pinmux@700008d4 {
57		pwm_active_state: pwm_active_state {
58                        pe7 {
59                                nvidia,pins = "pe7";
60                                nvidia,tristate = <TEGRA_PIN_DISABLE>;
61			};
62		};
63
64		pwm_sleep_state: pwm_sleep_state {
65                        pe7 {
66                                nvidia,pins = "pe7";
67                                nvidia,tristate = <TEGRA_PIN_ENABLE>;
68			};
69		};
70	};
71
72	pwm@7000a000 {
73		/* Mandatory PWM properties */
74		pinctrl-names = "default", "sleep";
75		pinctrl-0 = <&pwm_active_state>;
76		pinctrl-1 = <&pwm_sleep_state>;
77	};
78