Re: [PATCH] clk: stm32h7: Add stm32h743 clock driver

[Gabriel Fernandez <gabriel.fernandez@st.com>]

Hi Rob,

Thanks for reviewing


On 03/24/2017 03:06 AM, Rob Herring wrote:
> On Wed, Mar 15, 2017 at 10:23:30AM +0100, gabriel.fernandez@st.com wrote:
>> From: Gabriel Fernandez <gabriel.fernandez@st.com>
>>
>> This patch enables clocks for STM32H743 boards.
>>
>> Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
>> ---
>>   .../devicetree/bindings/clock/st,stm32h7-rcc.txt   |  152 ++
>>   drivers/clk/Makefile                               |    1 +
>>   drivers/clk/clk-stm32h7.c                          | 1586 ++++++++++++++++++++
>>   include/dt-bindings/clock/stm32h7-clks.h           |  165 ++
>>   include/dt-bindings/mfd/stm32h7-rcc.h              |  138 ++
>>   5 files changed, 2042 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt
>>   create mode 100644 drivers/clk/clk-stm32h7.c
>>   create mode 100644 include/dt-bindings/clock/stm32h7-clks.h
>>   create mode 100644 include/dt-bindings/mfd/stm32h7-rcc.h
>>
>> diff --git a/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt b/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt
>> new file mode 100644
>> index 0000000..9d4b587
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt
>> @@ -0,0 +1,152 @@
>> +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>;
> The reg addr value and unit address don't match.
ok il will change into

	vco1@0 {
		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"
> Only 1 single PLL design for all STM32 chips ever?
no, i can change into "stm32h7,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
> Isn't this implied by the presence of the next property?
do you prefer this ?

- st,frac :
0 : pll is configured in integer mode
1..8191 : Fractional part of the multiplication factor and pll is 
configured 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
> Seems like you could figure this out based on the input freq and other
> properties.
ok i will try to integrate pllrge configuration in the code.

>
>> +
>> +
>> +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)>;
>> +	};