st,stm32wba-rcc

Vendor: STMicroelectronics N.V.

Description

STM32 Reset and Clock controller node.
This node is in charge of system clock ('SYSCLK') source selection and controlling
clocks for AHB (Advanced High Performance) and APB (Advanced Peripheral) bus domains.

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_hsi', 'pll').
Core clock frequency should also be defined, using "clock-frequency" property.
Note:
        Core clock frequency  = SYSCLK / AHB prescaler
Last, peripheral bus clocks (typically PCLK1, PCLK2, PCLK7) should be configured using
matching prescaler properties.
Here is an example of correctly configured rcc node:
&rcc {
         clocks = <&pll>;                   /* Select pll as SYSCLK source */
         ahb-prescaler = <2>;
         clock-frequency = <DT_FREQ_M(40)>; /* = SYSCLK / AHB prescaler */
         apb1-presacler = <1>;
         apb2-presacler = <1>;
         apb7-presacler = <7>;
}

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.

Specifying an alternate clock source:

Specifying an alternate source clock could be done by adding a clock specifier to the
clock property:
... {
         ...
         clocks = <&rcc STM32_CLOCK_BUS_APB2 0x00000020>,
                      <&rcc STM32_SRC_HSI I2C1_SEL(2)>;
         ...
}
In this example I2C1 device is assigned HSI as clock source.
It is device driver's responsibility to query and use clock source information in
accordance with clock_control API specifications.

Properties

Node specific properties

Properties not inherited from the base binding file.

Name	Type	Details
#clock-cells	int	Number of items to expect in a Clock specifier This property is required. Constant value: 2
clock-frequency	int	default frequency in Hz for clock output (HCLK1) This property is required.
ahb-prescaler	int	Common AHB1, AHB2, AHB4 prescaler. Defines actual core clock frequency (HCLK) based on system frequency input. AKA HPRE. The HCLK clocks CPU, AHB1, AHB2, memories and DMA. This property is required. Legal values: 1, 2, 4, 8, 16
ahb5-prescaler	int	AHB5 prescaler. Defines actual core clock frequency (HCLK5) based on system frequency input. It is used to limit HCLK5 below 32MHz. Only required when SysClock source is PLL1. AKA HPRE5. Legal values: 1, 2, 3, 4, 6
apb1-prescaler	int	This property is required. Legal values: 1, 2, 4, 8, 16
apb2-prescaler	int	This property is required. Legal values: 1, 2, 4, 8, 16
apb7-prescaler	int	This property is required. Legal values: 1, 2, 4, 8, 16
ahb5-div	boolean	AHB5 divider. Applies only when SysClock source is HSI16 or HSE32. When enabled, AHB5 clock is SysClock / 2. When disabled, SysClock is not divided.

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 “st,stm32wba-rcc” compatible.

Name	Type	Details
reg	array	register space This property is required. See Important properties for more information.
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-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: bus, bits