Re: [PATCH] clk: stm32h7: Add stm32h743 clock driver
From: Gabriel Fernandez
Date: Fri Mar 24 2017 - 05:42:52 EST
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@xxxxxx wrote:
From: Gabriel Fernandez <gabriel.fernandez@xxxxxx>
This patch enables clocks for STM32H743 boards.
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@xxxxxx>
---
.../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)>;
+ };