:orphan:
.. raw:: html
.. dtcompatible:: st,stm32h7-rcc
.. _dtbinding_st_stm32h7_rcc:
st,stm32h7-rcc
##############
Vendor: :ref:`STMicroelectronics `
Description
***********
.. code-block:: none
STM32 Reset and Clock controller node for STM32H7 devices
This node is in charge of system clock ('SYSCLK') source selection and
System Clock Generation.
Configuring STM32 Reset and Clock controller node:
System clock source should be selected amongst the clock nodes available in "clocks"
node (typically 'clk_hse, clk_csi', 'pll', ...).
As part of this node configuration, SYSCLK frequency should also be defined, using
"clock-frequency" property.
Last, bus clocks (typically HCLK, PCLK1, PCLK2) should be configured using matching
prescaler properties.
Here is an example of correctly configured rcc node:
&rcc {
clocks = <&pll>; /* Set pll as SYSCLK source */
clock-frequency = ; /* SYSCLK runs at 480MHz */
d1cpre = <1>;
hpre = <1>;
d1ppre = <1>;
d2ppre1 = <1>;
d2ppre2 = <1>;
d3ppre = <1>;
}
Specifying a gated clock:
To specify a gated clock, a peripheral should define a "clocks" property encoded
in the following way:
... {
...
clocks = <&rcc STM32_CLOCK_BUS_APB2 0x00000020>;
...
}
After the phandle referring to rcc node, the first index specifies the registers of
the bus controlling the peripheral and the second index specifies the bit used to
control the peripheral clock in that bus register.
Note 1: No additional specifier means gating clock is also the clock source (ie
'PCLK/PCLK1/PCLK2' depending on the device). There is no need to add a second
cell to explicitly set it.
Note 2: Default peripheral clock configuration (ie the one provided in *.dsti files)
should be the one matching SoC reset state. Confere reference manual to check
what is the reset value of the kernel clock source for each peripheral.
Properties
**********
.. tabs::
.. group-tab:: Node specific properties
Properties not inherited from the base binding file.
.. list-table::
:widths: 1 1 4
:header-rows: 1
* - Name
- Type
- Details
* - ``#clock-cells``
- ``int``
- .. code-block:: none
Number of items to expect in a Clock specifier
This property is **required**.
Constant value: ``2``
* - ``clock-frequency``
- ``int``
- .. code-block:: none
default frequency in Hz for clock output
This property is **required**.
* - ``d1cpre``
- ``int``
- .. code-block:: none
D1 Domain, CPU1 clock prescaler. Sets a HCLK frequency (feeding Cortex-M Systick)
lower than SYSCLK frequency (actual core frequency).
Zephyr doesn't make a difference today between these two clocks.
Changing this prescaler is not allowed until it is made possible to
use them independently in Zephyr clock subsystem.
This property is **required**.
Legal values: ``1``
* - ``hpre``
- ``int``
- .. code-block:: none
D2 domain, CPU2 core clock and AHB(1/2/3/4) peripheral prescaler
This property is **required**.
Legal values: ``1``, ``2``, ``4``, ``8``, ``16``, ``64``, ``128``, ``256``, ``512``
* - ``d1ppre``
- ``int``
- .. code-block:: none
D1 domain, APB3 peripheral prescaler
This property is **required**.
Legal values: ``1``, ``2``, ``4``, ``8``, ``16``
* - ``d2ppre1``
- ``int``
- .. code-block:: none
D2 domain, APB1 peripheral prescaler
This property is **required**.
Legal values: ``1``, ``2``, ``4``, ``8``, ``16``
* - ``d2ppre2``
- ``int``
- .. code-block:: none
D2 domain, APB2 peripheral prescaler
This property is **required**.
Legal values: ``1``, ``2``, ``4``, ``8``, ``16``
* - ``d3ppre``
- ``int``
- .. code-block:: none
D3 domain, APB4 peripheral prescaler
This property is **required**.
Legal values: ``1``, ``2``, ``4``, ``8``, ``16``
.. group-tab:: Deprecated node specific properties
Deprecated properties not inherited from the base binding file.
(None)
.. group-tab:: 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 "st,stm32h7-rcc" compatible.
.. list-table::
:widths: 1 1 4
:header-rows: 1
* - Name
- Type
- Details
* - ``reg``
- ``array``
- .. code-block:: none
register space
This property is **required**.
See :ref:`dt-important-props` for more information.
* - ``status``
- ``string``
- .. code-block:: none
indicates the operational status of a device
Legal values: ``'ok'``, ``'okay'``, ``'disabled'``, ``'reserved'``, ``'fail'``, ``'fail-sss'``
See :ref:`dt-important-props` for more information.
* - ``compatible``
- ``string-array``
- .. code-block:: none
compatible strings
This property is **required**.
See :ref:`dt-important-props` for more information.
* - ``reg-names``
- ``string-array``
- .. code-block:: none
name of each register space
* - ``interrupts``
- ``array``
- .. code-block:: none
interrupts for device
See :ref:`dt-important-props` for more information.
* - ``interrupts-extended``
- ``compound``
- .. code-block:: none
extended interrupt specifier for device
* - ``interrupt-names``
- ``string-array``
- .. code-block:: none
name of each interrupt
* - ``interrupt-parent``
- ``phandle``
- .. code-block:: none
phandle to interrupt controller node
* - ``label``
- ``string``
- .. code-block:: none
Human readable string describing the device (used as device_get_binding() argument)
See :ref:`dt-important-props` for more information.
* - ``clocks``
- ``phandle-array``
- .. code-block:: none
Clock gate information
* - ``clock-names``
- ``string-array``
- .. code-block:: none
name of each clock
* - ``#address-cells``
- ``int``
- .. code-block:: none
number of address cells in reg property
* - ``#size-cells``
- ``int``
- .. code-block:: none
number of size cells in reg property
* - ``dmas``
- ``phandle-array``
- .. code-block:: none
DMA channels specifiers
* - ``dma-names``
- ``string-array``
- .. code-block:: none
Provided names of DMA channel specifiers
* - ``io-channels``
- ``phandle-array``
- .. code-block:: none
IO channels specifiers
* - ``io-channel-names``
- ``string-array``
- .. code-block:: none
Provided names of IO channel specifiers
* - ``mboxes``
- ``phandle-array``
- .. code-block:: none
mailbox / IPM channels specifiers
* - ``mbox-names``
- ``string-array``
- .. code-block:: none
Provided names of mailbox / IPM channel specifiers
* - ``wakeup-source``
- ``boolean``
- .. code-block:: none
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.
* - ``power-domain``
- ``phandle``
- .. code-block:: none
Power domain the device belongs to.
The device will be notified when the power domain it belongs to is either
suspended or resumed.
Specifier cell names
********************
- clock cells: bus, bits