[v3,1/2] dt: snps,designware-i2c: Add clock bindings documentation

From: Phil Edworthy <phil.edworthy@renesas.com>

The driver requires an undocumented clock property, so detail it.
Add documentation for a separate, optional, bus clock.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>

v3:
 - Changed clocks and clock-names sections to use term "peripheral clock"
   (pclk) instead of "bus clock" (busclk).
v2:
 - No changes.
v1:
 - Reviewed-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/i2c/i2c-designware.txt | 9 +++++++++
 1 file changed, 9 insertions(+)

On Wed, Feb 20, 2019 at 03:50:02PM +0000, Gareth Williams wrote:
> From: Phil Edworthy <phil.edworthy@renesas.com>
> 
> The driver requires an undocumented clock property, so detail it.
> Add documentation for a separate, optional, bus clock.
> 
> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>

Looks good to me:

Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Let's see what the designware maintainers have to say.

> 
> v3:
>  - Changed clocks and clock-names sections to use term "peripheral clock"
>    (pclk) instead of "bus clock" (busclk).
> v2:
>  - No changes.
> v1:
>  - Reviewed-by: Rob Herring <robh@kernel.org>
> ---
>  Documentation/devicetree/bindings/i2c/i2c-designware.txt | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> index 3e4bcc2..f94aa59 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> @@ -6,12 +6,21 @@ Required properties :
>                  or "mscc,ocelot-i2c" with "snps,designware-i2c" for fallback
>   - reg : Offset and length of the register set for the device
>   - interrupts : <IRQ> where IRQ is the interrupt number.
> + - clocks : phandles for the clocks, see the description of clock-names below.
> +   The phandle for the "ic_clk" clock is required. The phandle for the "pclk"
> +   clock is optional. If a single clock is specified but no clock-name, it is
> +   the "ic_clk" clock. If both clocks are listed, the "ic_clk" must be first.
>  
>  Recommended properties :
>  
>   - clock-frequency : desired I2C bus clock frequency in Hz.
>  
>  Optional properties :
> +
> + - clock-names : Contains the names of the clocks:
> +    "ic_clk", for the core clock used to generate the external I2C clock.
> +    "pclk", the peripheral clock, required for register accesses.
> +
>   - reg : for "mscc,ocelot-i2c", a second register set to configure the SDA hold
>     time, named ICPU_CFG:TWI_DELAY in the datasheet.
>  
> -- 
> 2.7.4
>