Re: [PATCH] dt-bindings: i2c: stm32: Migrate i2c-stm32 documentation to yaml

[Alain Volmat <alain.volmat@st.com>]

On Wed, Nov 20, 2019 at 05:53:37PM +0000, Rob Herring wrote:
> On Wed, Nov 20, 2019 at 7:43 AM Alain Volmat <alain.volmat@st.com> wrote:
> >
> > The document was migrated to Yaml format and renamed st,stm32-i2c.yaml
> >
> > Signed-off-by: Alain Volmat <alain.volmat@st.com>
> > ---
> >  .../devicetree/bindings/i2c/i2c-stm32.txt          |  65 ---------
> >  .../devicetree/bindings/i2c/st,stm32-i2c.yaml      | 157 +++++++++++++++++++++
> >  2 files changed, 157 insertions(+), 65 deletions(-)
> >  delete mode 100644 Documentation/devicetree/bindings/i2c/i2c-stm32.txt
> >  create mode 100644 Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/i2c/i2c-stm32.txt b/Documentation/devicetree/bindings/i2c/i2c-stm32.txt
> > deleted file mode 100644
> > index ce3df2fff6c8..000000000000
> > --- a/Documentation/devicetree/bindings/i2c/i2c-stm32.txt
> > +++ /dev/null
> > @@ -1,65 +0,0 @@
> > -* I2C controller embedded in STMicroelectronics STM32 I2C platform
> > -
> > -Required properties:
> > -- compatible: Must be one of the following
> > -  - "st,stm32f4-i2c"
> > -  - "st,stm32f7-i2c"
> > -- reg: Offset and length of the register set for the device
> > -- interrupts: Must contain the interrupt id for I2C event and then the
> > -  interrupt id for I2C error.
> > -- resets: Must contain the phandle to the reset controller.
> > -- clocks: Must contain the input clock of the I2C instance.
> > -- A pinctrl state named "default" must be defined to set pins in mode of
> > -  operation for I2C transfer
> > -- #address-cells = <1>;
> > -- #size-cells = <0>;
> > -
> > -Optional properties:
> > -- clock-frequency: Desired I2C bus clock frequency in Hz. If not specified,
> > -  the default 100 kHz frequency will be used.
> > -  For STM32F4 SoC Standard-mode and Fast-mode are supported, possible values are
> > -  100000 and 400000.
> > -  For STM32F7, STM32H7 and STM32MP1 SoCs, Standard-mode, Fast-mode and Fast-mode
> > -  Plus are supported, possible values are 100000, 400000 and 1000000.
> > -- dmas: List of phandles to rx and tx DMA channels. Refer to stm32-dma.txt.
> > -- dma-names: List of dma names. Valid names are: "rx" and "tx".
> > -- i2c-scl-rising-time-ns: I2C SCL Rising time for the board (default: 25)
> > -  For STM32F7, STM32H7 and STM32MP1 only.
> > -- i2c-scl-falling-time-ns: I2C SCL Falling time for the board (default: 10)
> > -  For STM32F7, STM32H7 and STM32MP1 only.
> > -  I2C Timings are derived from these 2 values
> > -- st,syscfg-fmp: Use to set Fast Mode Plus bit within SYSCFG when Fast Mode
> > -  Plus speed is selected by slave.
> > -       1st cell: phandle to syscfg
> > -       2nd cell: register offset within SYSCFG
> > -       3rd cell: register bitmask for FMP bit
> > -  For STM32F7, STM32H7 and STM32MP1 only.
> > -
> > -Example:
> > -
> > -       i2c@40005400 {
> > -               compatible = "st,stm32f4-i2c";
> > -               #address-cells = <1>;
> > -               #size-cells = <0>;
> > -               reg = <0x40005400 0x400>;
> > -               interrupts = <31>,
> > -                            <32>;
> > -               resets = <&rcc 277>;
> > -               clocks = <&rcc 0 149>;
> > -               pinctrl-0 = <&i2c1_sda_pin>, <&i2c1_scl_pin>;
> > -               pinctrl-names = "default";
> > -       };
> > -
> > -       i2c@40005400 {
> > -               compatible = "st,stm32f7-i2c";
> > -               #address-cells = <1>;
> > -               #size-cells = <0>;
> > -               reg = <0x40005400 0x400>;
> > -               interrupts = <31>,
> > -                            <32>;
> > -               resets = <&rcc STM32F7_APB1_RESET(I2C1)>;
> > -               clocks = <&rcc 1 CLK_I2C1>;
> > -               pinctrl-0 = <&i2c1_sda_pin>, <&i2c1_scl_pin>;
> > -               pinctrl-names = "default";
> > -               st,syscfg-fmp = <&syscfg 0x4 0x1>;
> > -       };
> > diff --git a/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml b/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml
> > new file mode 100644
> > index 000000000000..0f51a6ed0e9b
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml
> > @@ -0,0 +1,157 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/i2c/st,stm32-i2c.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: I2C controller embedded in STMicroelectronics STM32 I2C platform
> > +
> > +maintainers:
> > +  - Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
> > +
> > +allOf:
> > +  - $ref: /schemas/i2c/i2c-controller.yaml#
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            enum:
> > +              - st,stm32f7-i2c
> > +    then:
> > +      properties:
> > +        i2c-scl-rising-time-ns:
> > +          description: I2C SCL Rising time for the board
> > +          $ref: /schemas/types.yaml#/definitions/uint32
> > +          default: 25
> > +
> > +        i2c-scl-falling-time-ns:
> > +          description: I2C SCL Falling time for the board
> > +          $ref: /schemas/types.yaml#/definitions/uint32
> 
> These 2 should be added to i2c-controller.yaml and just the default
> defined here.

Pull-request on the dt-schema git sent in order to add those two properties
into the i2c-controller.yaml

Patch v2 to come regarding other points.

> 
> > +          default: 10
> > +
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            enum:
> > +              - st,stm32f4-i2c
> > +    then:
> > +      properties:
> > +        clock-frequency:
> > +          description: Desired I2C bus clock frequency in Hz. If not specified,
> > +                       the default 100 kHz frequency will be used.
> > +                       For STM32F4 SoC Standard-mode and Fast-mode are
> > +                       supported, possible values are 100000 and 400000.
> > +          default: 100000
> > +          enum: [100000, 400000]
> > +    else:
> > +      properties:
> > +        clock-frequency:
> > +          description: Desired I2C bus clock frequency in Hz. If not specified,
> > +                       the default 100 kHz frequency will be used.
> > +                       For STM32F7, STM32H7 and STM32MP1 SoCs, Standard-mode,
> > +                       Fast-mode and Fast-mode Plus are supported, possible
> > +                       values are 100000, 400000 and 1000000.
> > +          default: 100000
> > +          enum: [100000, 400000, 1000000]
> 
> Move this to main 'properties'. Then the one in the 'then' clause just
> needs the enum.
> 
> > +
> > +        st,syscfg-fmp:
> > +          $ref: "/schemas/types.yaml#/definitions/phandle-array"
> 
> Won't work. You have to do:
> 
> allOf:
>   - $ref: ...
> 
> > +          description: Use to set Fast Mode Plus bit within SYSCFG when
> > +                       Fast Mode Plus speed is selected by slave. Should be
> > +                       phandle/offset/mask
> > +          items:
> > +            - description: phandle to syscfg
> > +            - description: register offset within syscfg
> > +            - description: register bitmask for FMP bit
> 
> Wouldn't this make more sense in the first if rather than the 'else' clause?
> 
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - st,stm32f4-i2c
> > +      - st,stm32f7-i2c
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    maxItems: 2
> 
> Implied by items length.
> 
> > +    items:
> > +      - description: interrupt ID for I2C event
> > +      - description: interrupt ID for I2C error
> > +
> > +  resets:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    maxItems: 1
> > +
> > +  dmas:
> > +    items:
> > +      - description: RX DMA Channel phandle
> > +      - description: TX DMA Channel phandle
> > +    minItems: 2
> > +    maxItems: 2
> 
> Implied by items length.
> 
> > +
> > +  dma-names:
> > +    items:
> > +      - const: rx
> > +      - const: tx
> > +    minItems: 2
> > +    maxItems: 2
> 
> Implied by items length.
> 
> > +
> > +required:
> > +  - compatible
> 
> > +  - '#address-cells'
> > +  - '#size-cells'
> 
> Can drop. i2c-controller.yaml makes them required.
> 
> > +  - reg
> > +  - interrupts
> > +  - resets
> > +  - clocks
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/mfd/stm32f7-rcc.h>
> > +    #include <dt-bindings/clock/stm32fx-clock.h>
> > +    //Example 1 (with st,stm32f4-i2c compatible)
> > +      i2c@40005400 {
> > +          compatible = "st,stm32f4-i2c";
> > +          #address-cells = <1>;
> > +          #size-cells = <0>;
> > +          reg = <0x40005400 0x400>;
> > +          interrupts = <31>,
> > +                       <32>;
> > +          resets = <&rcc 277>;
> > +          clocks = <&rcc 0 149>;
> > +      };
> > +
> > +    //Example 2 (with st,stm32f7-i2c compatible)
> > +      i2c@40005800 {
> > +          compatible = "st,stm32f7-i2c";
> > +          #address-cells = <1>;
> > +          #size-cells = <0>;
> > +          reg = <0x40005800 0x400>;
> > +          interrupts = <31>,
> > +                       <32>;
> > +          resets = <&rcc STM32F7_APB1_RESET(I2C1)>;
> > +          clocks = <&rcc 1 CLK_I2C1>;
> > +      };
> > +
> > +    //Example 3 (with st,stm32f7-i2c compatible on stm32mp)
> > +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> > +    #include <dt-bindings/clock/stm32mp1-clks.h>
> > +    #include <dt-bindings/reset/stm32mp1-resets.h>
> > +      i2c@40013000 {
> > +          compatible = "st,stm32f7-i2c";
> > +          #address-cells = <1>;
> > +          #size-cells = <0>;
> > +          reg = <0x40013000 0x400>;
> > +          interrupts = <GIC_SPI 33 IRQ_TYPE_LEVEL_HIGH>,
> > +                       <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>;
> > +          clocks = <&rcc I2C2_K>;
> > +          resets = <&rcc I2C2_R>;
> > +          i2c-scl-rising-time-ns = <185>;
> > +          i2c-scl-falling-time-ns = <20>;
> > +          st,syscfg-fmp = <&syscfg 0x4 0x2>;
> > +      };
> > +...
> > --
> > 2.7.4
> >