On Tue, Aug 19, 2014 at 07:34:35PM +0100, atull@xxxxxxxxxxxxxxxxxxxxx wrote:
> From: Alan Tull <atull@xxxxxxxxxxxxxxxxxxxxx>
>
> Add "speed-mode" Device Tree property to select between
> standard and fast i2c mode. Previously, driver was hardwired
> as fast mode. Default to fast mode if property is not
> present.
>
> Signed-off-by: Alan Tull <atull@xxxxxxxxxxxxxxxxxxxxx>
> ---
> .../devicetree/bindings/i2c/i2c-designware.txt | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> index 5199b0c..0e4cd21 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> @@ -9,6 +9,8 @@ Required properties :
> Recommended properties :
>
> - clock-frequency : desired I2C bus clock frequency in Hz.
> + - speed-mode : 0 = standard (0 - 100Kb/s)
> + : 1 = fast (<= 400Kb/s) <== default
This is a bit opaque.
Is this a limit on the max bit-rate the device should operate at?
Why not just have an optional boolean property to limit to standard
speed?
Thanks,
Mark.
>
> Optional properties :
> - i2c-sda-hold-time-ns : should contain the SDA hold time in nanoseconds.
> @@ -29,6 +31,7 @@ Example :
> reg = <0xf0000 0x1000>;
> interrupts = <11>;
> clock-frequency = <400000>;
> + speed-mode = <0>;
> };
>
> i2c@1120000 {
> --
> 1.7.9.5
>
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