Re: [PATCH v2 01/16] dt-bindings: mvebu-uart: update documentation with extended UART

[Rob Herring <robh@kernel.org>]

On Fri, Oct 13, 2017 at 11:01:45AM +0200, Miquel Raynal wrote:
> Update the Device Tree binding documentation for the Marvell EBU UART,
> in order to allow describing the extended UART IP block, in addition to
> the already supported standard UART IP. This requires adding a new
> compatible string, the introduction of a clocks property, and extensions
> to the interrupts property.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons.com>
> Reviewed-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
> ---
>  .../devicetree/bindings/serial/mvebu-uart.txt      | 49 +++++++++++++++++++---
>  1 file changed, 44 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/serial/mvebu-uart.txt b/Documentation/devicetree/bindings/serial/mvebu-uart.txt
> index d37fabe17bd1..3df3a3fab4bb 100644
> --- a/Documentation/devicetree/bindings/serial/mvebu-uart.txt
> +++ b/Documentation/devicetree/bindings/serial/mvebu-uart.txt
> @@ -1,13 +1,52 @@
> -* Marvell UART : Non standard UART used in some of Marvell EBU SoCs (e.g., Armada-3700)
> +* Marvell UART : Non standard UART used in some of Marvell EBU SoCs
> +                 e.g., Armada-3700.
>  
>  Required properties:
> -- compatible: "marvell,armada-3700-uart"
> +- compatible:
> +    - "marvell,armada-3700-uart" for the standard variant of the UART
> +      (32 bytes FIFO, no DMA, level interrupts, 8-bit access to the
> +      FIFO, baudrate limited to 230400).
> +    - "marvell,armada-3700-uart-ext" for the extended variant of the
> +      UART (128 bytes FIFO, DMA, front interrupts, 8-bit or 32-bit
> +      accesses to the FIFO, baudrate unlimited by the dividers).

What do you call the next extended version? marvell,armada-3700-uart-ext-ext?

This is different versions of UART on the same chip?

>  - reg: offset and length of the register set for the device.
> -- interrupts: device interrupt
> +- clocks: UART reference clock used to derive the baudrate (only
> +      mandatory with "marvell,armada-3700-uart-ext" compatible).

How is this optional? The freq is fixed if not present? If so, what 
frequency?

> +- interrupts:
> +    - Must contain three elements for the standard variant of the IP
> +      (marvell,armada-3700-uart): "uart-sum", "uart-tx" and "uart-rx",
> +      respectively the UART sum interrupt, the UART TX interrupt and
> +      UART RX interrupt. A corresponding interrupt-names property must
> +      be defined.
> +    - Must contain two elements for the extended variant of the IP
> +      (marvell,armada-3700-uart-ext): "uart-tx" and "uart-rx",
> +      respectively the UART TX interrupt and the UART RX interrupt. A
> +      corresponding interrupts-names property must be defined.
> +    - For backward compatibility reasons, a single element interrupts
> +      property is also supported for the standard variant of the IP,
> +      containing only the UART sum interrupt. This form is deprecated
> +      and should no longer be used.
>  
>  Example:
> -	serial@12000 {
> +	uart0: serial@12000 {
>  		compatible = "marvell,armada-3700-uart";
>  		reg = <0x12000 0x200>;
> -		interrupts = <43>;
> +		clocks = <&xtalclk>;
> +		interrupts =
> +		<GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>,
> +		<GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>,
> +		<GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>;
> +		interrupt-names = "uart-sum", "uart-tx", "uart-rx";
> +		status = "disabled";

Don't show status in examples.

> +	};
> +
> +	uart1: serial@12200 {
> +		compatible = "marvell,armada-3700-uart-ext";
> +		reg = <0x12200 0x30>;
> +		clocks = <&xtalclk>;
> +		interrupts =
> +		<GIC_SPI 30 IRQ_TYPE_EDGE_RISING>,
> +		<GIC_SPI 31 IRQ_TYPE_EDGE_RISING>;
> +		interrupt-names = "uart-tx", "uart-rx";
> +		status = "disabled";
>  	};
> -- 
> 2.11.0
> 
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