nxp,s32-emios-pwm

Vendor: NXP Semiconductors

Description

NXP S32 eMIOS PWM node for S32 SoCs. Each channel in eMIOS can be configured
to use for PWM operation. There are several PWM modes supported by this module,
some modes only support on channels that have internal counter, some modes
require to use a reference timebase from a master bus.

For example to configuring eMIOS instance 0 with:
  - Channel 0 for mode OPWFMB
  - Channel 1 for mode OPWMB
  - Channel 2 for mode OPWMCB with deadtime inserted at leading edge
  - Channel 3 for mode SAIC, use internal timebase with input filter = 2 eMIOS clock

  emios0_pwm: pwm {
    pwm_0 {
      channel = <0>;
      pwm-mode = "OPWFMB";
      prescaler = <8>;
      period = <65534>;
      duty-cycle = <32768>;
      polarity = "ACTIVE_HIGH";
    };

    pwm_1 {
      channel = <1>;
      master-bus = <&emios1_bus_a>;
      pwm-mode = "OPWMB";
      duty-cycle = <32768>;
      phase-shift = <100>;
      polarity = "ACTIVE_LOW";
    };

    pwm_2 {
      channel = <2>;
      master-bus = <&emios1_bus_b>;
      pwm-mode = "OPWMCB_LEAD_EDGE";
      duty-cycle = <32768>;
      dead-time = <100>;
      polarity = "ACTIVE_LOW";
    };

    pwm_3 {
      channel = <3>;
      pwm-mode = "SAIC";
      prescaler = <8>;
      input-filter = <2>;
    };
  };

OPWMB and OPWMCB modes use reference timebase, the master bus is chosen over
phandle 'master-bus'. For OPWMB mode, PWM's period is master bus's period and
is 2 * master bus's period - 2 for OPWMCB mode. Please notice that the devicetree
node for master bus should be enabled and configured for using, please see
'nxp,s32-emios' bindings.

Properties

Top level properties

These property descriptions apply to “nxp,s32-emios-pwm” nodes themselves. This page also describes child node properties in the following sections.

Properties not inherited from the base binding file.

Name

Type

Details

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-names

string-array

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

This property is required.

#pwm-cells

int

 
Number of items to expect in a pwm specifier

This property is required.

Constant value: 3

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.

Child node properties

Name

Type

Details

channel

int

 
eMIOS PWM channel

This property is required.

master-bus

phandle

 
A phandle to master-bus node that will be used as external timebase
for current channel, this can be bypassed if internal counter is used
for PWM operation. A master bus must be used exclusively, such as if
is used as a timebase for a channel in SAIC mode, do not use that
master bus as a timebase for generate PWM pulse.

pwm-mode

string

 
Select PWM mode:
- OPWFMB: provides waveforms with variable duty cycle and frequency,
          this mode uses internal counter.

- OPWMB:  generate pulses with programmable leading and trailing
          edge placement. The period is determined by period of
          an external counter driven in MCB Up Mode. Changing PWM period
          at runtime will impact to all channels share the same timebase.
          The new period and cycle take effect in next period boundary.

- OPWMCB: generates a center aligned PWM with dead time insertion to the
          leading or trailing edge. The period is determined by period of
          an external counter driven in MCB Up Down Mode. Changing PWM period
          at runtime will impact to all channels share the same timebase,
          The new period and cycle take effect in next period boundary.

- SAIC: single action input capture mode, the eMIOS captures events as soon as
        they occur. The value of latest captured event is stored and can be read
        by software.

This property is required.

Legal values: 'OPWFMB', 'OPWMB', 'OPWMCB_TRAIL_EDGE', 'OPWMCB_LEAD_EDGE', 'SAIC'

polarity

string

 
Output polarity for PWM channel.

Legal values: 'ACTIVE_LOW', 'ACTIVE_HIGH'

duty-cycle

int

 
Duty-cycle (in ticks) for PWM channel at boot time.

period

int

 
Period (in ticks) for OPWFMB at boot time. Period for the rest
of PWM mode depends on period's master bus. Must be in range [2 ... 65535].

freeze

boolean

 
Freeze individual internal counter when the chip enters Debug mode.

prescaler-src

string

 
Select clock source for internal counter prescaler.

Default value: PRESCALED_CLOCK

Legal values: 'PRESCALED_CLOCK', 'MODULE_CLOCK'

prescaler

int

 
The clock divider for internal counter prescaler.

Legal values: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16

dead-time

int

 
Dead time (in ticks) for PWM channel in OPWMCB mode.

phase-shift

int

 
Phase Shift (in ticks) for PWM channel in OPWMB mode.

input-filter

int

 
Select the minimum input pulse width, in filter clock cycles that can pass
through the input filter. The filter latency - the difference in time between
the input and the response is three clock edges. Default 0 means the filter
is bypassed. The clock source for programmable input filter is eMIOS clock.

Legal values: 0, 2, 4, 8, 16

Specifier cell names

  • pwm cells: channel, period, flags