pwm-clock

Vendor: Generic or vendor-independent

Note

An implementation of a driver matching this compatible is available in drivers/clock_control/clock_control_pwm.c.

Description

An external clock signal driven by a PWM pin.

The devicetree must define a clock node:

pwmclock: pwmclock {
    status = "okay";
    compatible = "pwm-clock";
    #clock-cells = <1>;
    pwms = <&pwm_ccu40 2 PWM_HZ(1000000) PWM_POLARITY_NORMAL>;
};

This will create a device node with a clock-controller
API. Internally the device node will use PWM API to start the
clock signals at 1MHz. Note that the PWM_HZ() macro converts the
frequency to time (nanoseconds units). This may result in rounding
errors if the clock frequency is not an integer number of nanoseconds.
The clock frequency can be explicitly set using the clock-frequency
property.

The PWM node may need to be properly configured to generate
the target period (i.e. using prescaler options). See the documentation
for the target PWM driver.

Properties

Node specific properties

Properties not inherited from the base binding file.

Name	Type	Details
pwms	phandle-array	This property is required.
clock-frequency	int	Exact output frequency, in case the PWM period is not exact but was rounded to nanoseconds. This property is optional.
pwm-on-delay	int	Optional blocking delay in micro seconds to make sure that the PWM clock has started after returning from clock_control_on().
#clock-cells	int	Number of items to expect in a Clock specifier This property is required. Constant value: 1

Deprecated node specific properties

Deprecated properties not inherited from the base binding file.

(None)

Base properties

Properties inherited from the base binding file, which defines common properties that may be set on many nodes. Not all of these may apply to the “pwm-clock” compatible.

Name	Type	Details
status	string	indicates the operational status of a device Legal values: 'ok', 'okay', 'disabled', 'reserved', 'fail', 'fail-sss' See Important properties for more information.
compatible	string-array	compatible strings This property is required. See Important properties for more information.
reg	array	register space See Important properties for more information.
reg-names	string-array	name of each register space
interrupts	array	interrupts for device See Important properties for more information.
interrupts-extended	compound	extended interrupt specifier for device
interrupt-names	string-array	name of each interrupt
interrupt-parent	phandle	phandle to interrupt controller node
label	string	Human readable string describing the device (used as device_get_binding() argument) See Important properties for more information. This property is deprecated.
clocks	phandle-array	Clock gate information
clock-names	string-array	name of each clock
#address-cells	int	number of address cells in reg property
#size-cells	int	number of size cells in reg property
dmas	phandle-array	DMA channels specifiers
dma-names	string-array	Provided names of DMA channel specifiers
io-channels	phandle-array	IO channels specifiers
io-channel-names	string-array	Provided names of IO channel specifiers
mboxes	phandle-array	mailbox / IPM channels specifiers
mbox-names	string-array	Provided names of mailbox / IPM channel specifiers
power-domains	phandle-array	Power domain specifiers
power-domain-names	string-array	Provided names of power domain specifiers
#power-domain-cells	int	Number of cells in power-domains property
zephyr,deferred-init	boolean	Do not initialize device automatically on boot. Device should be manually initialized using device_init().
wakeup-source	boolean	Property to identify that a device can be used as wake up source. When this property is provided a specific flag is set into the device that tells the system that the device is capable of wake up the system. Wake up capable devices are disabled (interruptions will not wake up the system) by default but they can be enabled at runtime if necessary.
zephyr,pm-device-runtime-auto	boolean	Automatically configure the device for runtime power management after the init function runs.
zephyr,disabling-power-states	phandles	List of power states that will disable this device power.

Specifier cell names

• clock cells: id