mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-08-20 17:08:52 +09:00
153 lines
4.0 KiB
Plaintext
153 lines
4.0 KiB
Plaintext
![]() |
STMicroelectronics STM32H7 Reset and Clock Controller
|
||
|
=====================================================
|
||
|
|
||
|
The RCC IP is both a reset and a clock controller.
|
||
|
|
||
|
Please refer to clock-bindings.txt for common clock controller binding usage.
|
||
|
Please also refer to reset.txt for common reset controller binding usage.
|
||
|
|
||
|
Required properties:
|
||
|
- compatible: Should be:
|
||
|
"st,stm32h743-rcc"
|
||
|
|
||
|
- reg: should be register base and length as documented in the
|
||
|
datasheet
|
||
|
|
||
|
- #reset-cells: 1, see below
|
||
|
|
||
|
- #clock-cells : from common clock binding; shall be set to 1
|
||
|
|
||
|
- clocks: External oscillator clock phandle
|
||
|
- high speed external clock signal (HSE)
|
||
|
- low speed external clock signal (LSE)
|
||
|
- external I2S clock (I2S_CKIN)
|
||
|
|
||
|
- st,syscfg: phandle for pwrcfg, mandatory to disable/enable backup domain
|
||
|
write protection (RTC clock).
|
||
|
|
||
|
- pll x node: Allow to register a pll with specific parameters.
|
||
|
Please see PLL section below.
|
||
|
|
||
|
Example:
|
||
|
|
||
|
rcc: rcc@58024400 {
|
||
|
#reset-cells = <1>;
|
||
|
#clock-cells = <2>
|
||
|
compatible = "st,stm32h743-rcc", "st,stm32-rcc";
|
||
|
reg = <0x58024400 0x400>;
|
||
|
clocks = <&clk_hse>, <&clk_lse>, <&clk_i2s_ckin>;
|
||
|
|
||
|
st,syscfg = <&pwrcfg>;
|
||
|
|
||
|
#address-cells = <1>;
|
||
|
#size-cells = <0>;
|
||
|
|
||
|
vco1@58024430 {
|
||
|
#clock-cells = <0>;
|
||
|
compatible = "stm32,pll";
|
||
|
reg = <0>;
|
||
|
};
|
||
|
|
||
|
vco2@58024438 {
|
||
|
#clock-cells = <0>;
|
||
|
compatible = "stm32,pll";
|
||
|
reg = <1>;
|
||
|
st,clock-div = <2>;
|
||
|
st,clock-mult = <40>;
|
||
|
st,frac-status = <0>;
|
||
|
st,frac = <0>;
|
||
|
st,vcosel = <1>;
|
||
|
st,pllrge = <2>;
|
||
|
};
|
||
|
};
|
||
|
|
||
|
|
||
|
STM32H7 PLL
|
||
|
-----------
|
||
|
|
||
|
The VCO of STM32 PLL could be reprensented like this:
|
||
|
|
||
|
Vref --------- --------
|
||
|
---->| / DIVM |---->| x DIVN | ------> VCO
|
||
|
--------- --------
|
||
|
^
|
||
|
|
|
||
|
-------
|
||
|
| FRACN |
|
||
|
-------
|
||
|
|
||
|
When the PLL is configured in integer mode:
|
||
|
- VCO = ( Vref / DIVM ) * DIVN
|
||
|
|
||
|
When the PLL is configured in fractional mode:
|
||
|
- VCO = ( Vref / DIVM ) * ( DIVN + FRACN / 2^13)
|
||
|
|
||
|
|
||
|
Required properties for pll node:
|
||
|
- compatible: Should be:
|
||
|
"stm32,pll"
|
||
|
|
||
|
- #clock-cells: from common clock binding; shall be set to 0
|
||
|
- reg: Should be the pll number.
|
||
|
|
||
|
Optional properties:
|
||
|
- st,clock-div: DIVM division factor : <1..63>
|
||
|
- st,clock-mult: DIVN multiplication factor : <4..512>
|
||
|
|
||
|
- st,frac-status:
|
||
|
- 0 Pll is configured in integer mode
|
||
|
- 1 Pll is configure in fractional mode
|
||
|
|
||
|
- st,frac: Fractional part of the multiplication factor : <0..8191>
|
||
|
|
||
|
- st,vcosel: VCO selection
|
||
|
- 0: Wide VCO range:192 to 836 MHz
|
||
|
- 1: Medium VCO range:150 to 420 MHz
|
||
|
|
||
|
- st,pllrge: PLL input frequency range
|
||
|
- 0: The PLL input (Vref / DIVM) clock range frequency is between 1 and 2 MHz
|
||
|
- 1: The PLL input (Vref / DIVM) clock range frequency is between 2 and 4 MHz
|
||
|
- 2: The PLL input (Vref / DIVM) clock range frequency is between 4 and 8 MHz
|
||
|
- 3: The PLL input (Vref / DIVM) clock range frequency is between 8 and 16 MHz
|
||
|
|
||
|
|
||
|
The peripheral clock consumer should specify the desired clock by
|
||
|
having the clock ID in its "clocks" phandle cell.
|
||
|
|
||
|
All available clocks are defined as preprocessor macros in
|
||
|
dt-bindings/clock/stm32h7-clks.h header and can be used in device
|
||
|
tree sources.
|
||
|
|
||
|
Example:
|
||
|
|
||
|
timer5: timer@40000c00 {
|
||
|
compatible = "st,stm32-timer";
|
||
|
reg = <0x40000c00 0x400>;
|
||
|
interrupts = <50>;
|
||
|
clocks = <&rcc TIM5_CK>;
|
||
|
|
||
|
};
|
||
|
|
||
|
Specifying softreset control of devices
|
||
|
=======================================
|
||
|
|
||
|
Device nodes should specify the reset channel required in their "resets"
|
||
|
property, containing a phandle to the reset device node and an index specifying
|
||
|
which channel to use.
|
||
|
The index is the bit number within the RCC registers bank, starting from RCC
|
||
|
base address.
|
||
|
It is calculated as: index = register_offset / 4 * 32 + bit_offset.
|
||
|
Where bit_offset is the bit offset within the register.
|
||
|
|
||
|
For example, for CRC reset:
|
||
|
crc = AHB4RSTR_offset / 4 * 32 + CRCRST_bit_offset = 0x88 / 4 * 32 + 19 = 1107
|
||
|
|
||
|
All available preprocessor macros for reset are defined dt-bindings//mfd/stm32h7-rcc.h
|
||
|
header and can be used in device tree sources.
|
||
|
|
||
|
example:
|
||
|
|
||
|
timer2 {
|
||
|
resets = <&rcc STM32H7_APB1L_RESET(TIM2)>;
|
||
|
};
|