1 Specifying PWM information for devices
2 ======================================
3
4 1) PWM user nodes
5 -----------------
6
7 PWM users should specify a list of PWM devices
8 with a property containing a 'pwm-list':
9
10 pwm-list ::= <single-pwm> [pwm-list]
11 single-pwm ::= <pwm-phandle> <pwm-spec
12 pwm-phandle : phandle to PWM controlle
13 pwm-specifier : array of #pwm-cells sp
14 (controller specific)
15
16 PWM properties should be named "pwms". The exa
17 property must be documented in the device tree
18 An optional property "pwm-names" may contain a
19 each of the PWM devices listed in the "pwms" p
20 property is given, the name of the user node w
21
22 Drivers for devices that use more than a singl
23 "pwm-names" property to map the name of the PW
24 pwm_get() call to an index into the list given
25
26 The following example could be used to describ
27 device:
28
29 pwm: pwm {
30 #pwm-cells = <2>;
31 };
32
33 [...]
34
35 bl: backlight {
36 pwms = <&pwm 0 5000000>;
37 pwm-names = "backlight";
38 };
39
40 Note that in the example above, specifying the
41 because the name "backlight" would be used as
42
43 pwm-specifier typically encodes the chip-relat
44 period in nanoseconds.
45
46 Optionally, the pwm-specifier can encode a num
47 <dt-bindings/pwm/pwm.h>) in a third cell:
48 - PWM_POLARITY_INVERTED: invert the PWM signal
49
50 Example with optional PWM specifier for invers
51
52 bl: backlight {
53 pwms = <&pwm 0 5000000 PWM_POL
54 pwm-names = "backlight";
55 };
56
57 2) PWM controller nodes
58 -----------------------
59
60 See pwm.yaml.
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