infineon,xmc4xxx-ccu4-pwm

Vendor: Infineon Technologies

Description

Infineon XMC4XXX PWM Capture Compare Unit 4 (CCU4) module

The are four CCU4 modules with dts node labels:
pwm_ccu40, pwm_ccu41, pwm_ccu42, pwm_ccu43.
Each module has four slices and each slice has one channel.
A channel is connected to a particular gpio pin, which are defined
using pinctrl in:
dts/arm/infineon/xmc4xxx_xxx-pinctrl.dtsi

The CCU4 modules uses the CCU clock source. Each slice applies a separate
prescalar which divides the clock.

Device tree example:
A node can define a 'pwm' field, usually referenced in a 'pwms'
property, where the entries include the PWM module phandle,
channel number, pulse period (in nanoseconds or set using
PWM_XX() macros), and a channela
flag (PWM_POLARITY_NORMAL/PWM_POLARITY_INVERTED).

The pwm ccu4 node must define the slice-prescaler values and the pinctrl nodes:
&pwm_ccu40 {
    slice-prescaler = <15 15 15 15>;
    pinctrl-0 = <&pwm_out_p1_1_ccu40_ch2>;
    pinctrl-names = "default";
};

Another node can reference the PWM as follows:
&test_node {
   ...
   pwms = <&pwm_ccu40 0 PWM_SEC(1) PWM_POLARITY_NORMAL>;
   ...
};

The user must also explicitly set pinctrl properties.
The pin should be configured with drive-push-pull bool option and hwctrl should be set
to disabled. The drive-strength field can be set to any of the supported values:
&pwm_out_p1_1_ccu40_ch2 {
    drive-strength = "strong-medium-edge";
    drive-push-pull;
    hwctrl = "disabled";
};

The CCU4 pinctrl nodes have a node labels in the format
pwm_out_p{PORT}_{PIN}_ccu4{MODULE_IDX}_ch{CHANNEL_IDX}, where MODULE_IDX and
CHANNEL_IDX refers to specific pwm_ccu4x module and channel, respectively.
PORT/PIN pair defines what gpio the channel connects to.

Properties

Properties not inherited from the base binding file.

Name

Type

Details

#pwm-cells

int

Number of items to expect in a pwm specifier

This property is required.

Constant value: 3

pinctrl-0

phandles

Pin configuration/s for the first state. Content is specific to the
selected pin controller driver implementation.

This property is required.

pinctrl-1

phandles

Pin configuration/s for the second state. See pinctrl-0.

pinctrl-2

phandles

Pin configuration/s for the third state. See pinctrl-0.

pinctrl-3

phandles

Pin configuration/s for the fourth state. See pinctrl-0.

pinctrl-4

phandles

Pin configuration/s for the fifth state. See pinctrl-0.

pinctrl-names

string-array

Names for the provided states. The number of names needs to match the
number of states.

This property is required.

slice-prescaler

array

Defines the clock divider for each channel.
The entry in the array will divide CCU clock by (2 << value).
The range for the prescaler values is [0, 15].
Reducing prescaler value will improve resolution but decrease the maximum period.

This property is required.

Specifier cell names

  • pwm cells: channel, period, flags