infineon,xmc4xxx-ccu8-pwm
Vendor: Infineon Technologies
Note
An implementation of a driver matching this compatible is available in drivers/pwm/pwm_xmc4xxx_ccu8.c.
Description
Infineon XMC4XXX PWM Capture Compare Unit 8 (CCU8) module
The PWM CCU8 module can automatically generate a high-side
and a low-side PWM signal, where the two signals are complementary
to each other.
The module supports adding a dead time between the high-side and
low-side PWM signals.
The dead time ensures that there is a delay before the PWM state
transitions from 0 to 1, preventing the high-side and low-side
switches from being on simultaneously.
There are two CCU8 modules with DTS node labels: pwm_ccu80 and
pwm_ccu81. Each module has four slices, and each slice has
two channels. A channel consists of a corresponding high-side
and low-side PWM signal.
The CCU8 modules use the CCU clock source. Each slice applies
a separate prescaler to divide the clock. The clock divider is
defined by the 'slice-prescaler' property. Additionally, each
slice has a dead time prescaler, which divides the slice clock
for the dead time counter.
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 channel
flag (PWM_POLARITY_NORMAL/PWM_POLARITY_INVERTED).
The 'pwm_ccu8' node must define the following fields:
&pwm_ccu80 {
slice-prescaler = <15 15 15 15>;
slice-deadtime-prescaler = <3 3 3 3>;
channel-deadtime-high = <0 0 0 0 PWM_MSEC(100) 0 0 0>;
channel-deadtime-low = <0 0 0 0 PWM_MSEC(100) 0 0 0>;
pinctrl-0 = <&pwm_out_p5_9_ccu80_ch4_high &pwm_out_p0_0_ccu80_ch4_low>;
pinctrl-names = "default";
};
This will configure channel 4 with a 100msec deadtime on the high
and low side PWM signals.
Another node can reference the PWM as follows:
&test_node {
...
pwms = <&pwm_ccu80 0 PWM_SEC(1) PWM_POLARITY_NORMAL>;
...
};
The 'pwm_out_p{PORT}_{PIN}_ccu8{MODULE_IDX}_ch{CHANNEL_IDX}_{HIGH_LOW}'
format is used for CCU8 pinctrl nodes. 'MODULE_IDX' and 'CHANNEL_IDX'
refer to a specific 'pwm_ccu8x' module and channel, respectively.
'PORT/PIN' defines the GPIO that the channel connects to.
'HIGH_LOW' indicates whether the pin is for the high or low-side signal.
It's not necessary to specify both the high and low pinctrls. Only the low-side
signal can, for example, be used as PWM, but note that the duty cycle of the
low signal will be (1 - duty) as set via the API.
Note that a slice has two channels. Channels 0/1 are in slice 0,
channels 2/3 are in slice 1, and so on. Each channel can have its own
duty cycle and high/low dead times. But the pulse duration applies to
both channels. Thus, when using the PWM control api to modify the pulse width
on a channel 0, it will also be updated for channel 1 since they are
in the same slice.
Properties
Node specific properties
Properties not inherited from the base binding file.
Name |
Type |
Details |
|---|---|---|
|
|
Pin configuration/s for the first state. Content is specific to the
selected pin controller driver implementation.
This property is required. |
|
|
Names for the provided states. The number of names needs to match the
number of states.
This property is required. |
|
|
Defines the clock divider for each slice.
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. |
|
|
Defines the clock divider for dead time counter for each slice.
The range for the values is [0, 3].
Reducing prescaler value will improve dead time resolution but decrease the
maximum dead time.
This property is required. |
|
|
Defines the dead time in nanoseconds for the high-side PWM signal for each channel.
This property is required. |
|
|
Defines the dead time in nanoseconds for the low-side PWM signal for each channel.
This property is required. |
|
|
Number of items to expect in a pwm specifier
This property is required. Constant value: |
|
|
Pin configuration/s for the second state. See pinctrl-0.
|
|
|
Pin configuration/s for the third state. See pinctrl-0.
|
|
|
Pin configuration/s for the fourth state. See pinctrl-0.
|
|
|
Pin configuration/s for the fifth state. See pinctrl-0.
|
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 “infineon,xmc4xxx-ccu8-pwm” compatible.
Name |
Type |
Details |
|---|---|---|
|
|
register space
This property is required. See Important properties for more information. |
|
|
indicates the operational status of a device
Legal values: See Important properties for more information. |
|
|
compatible strings
This property is required. See Important properties for more information. |
|
|
name of each register space
|
|
|
interrupts for device
See Important properties for more information. |
|
|
extended interrupt specifier for device
|
|
|
name of each interrupt
|
|
|
phandle to interrupt controller node
|
|
|
Human readable string describing the device (used as device_get_binding() argument)
See Important properties for more information. This property is deprecated. |
|
|
Clock gate information
|
|
|
name of each clock
|
|
|
number of address cells in reg property
|
|
|
number of size cells in reg property
|
|
|
DMA channels specifiers
|
|
|
Provided names of DMA channel specifiers
|
|
|
IO channels specifiers
|
|
|
Provided names of IO channel specifiers
|
|
|
mailbox / IPM channels specifiers
|
|
|
Provided names of mailbox / IPM channel specifiers
|
|
|
Power domain specifiers
|
|
|
Provided names of power domain specifiers
|
|
|
Number of cells in power-domains property
|
|
|
Do not initialize device automatically on boot. Device should be manually
initialized using device_init().
|
|
|
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.
|
|
|
Automatically configure the device for runtime power management after the
init function runs.
|
|
|
List of power states that will disable this device power.
|
Specifier cell names
pwm cells: channel, period, flags