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From:   Rob Herring <robh+dt@kernel.org>
Date:   Wed, 20 Nov 2019 11:53:37 -0600
Message-ID: <CAL_Jsq+3GzLW7_hi56VFHT-V_LMv5g_K=x9ExGx0Xf6Hn_HR3Q@mail.gmail.com>
Subject: Re: [PATCH] dt-bindings: i2c: stm32: Migrate i2c-stm32 documentation
 to yaml
To:     Alain Volmat <alain.volmat@st.com>
Cc:     Wolfram Sang <wsa@the-dreams.de>,
        Mark Rutland <mark.rutland@arm.com>,
        Pierre-Yves MORDRET <pierre-yves.mordret@st.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        Linux I2C <linux-i2c@vger.kernel.org>,
        devicetree@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Fabrice Gasnier <fabrice.gasnier@st.com>
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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.

> +          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
>