On Tue, Feb 20, 2018 at 03:13:24AM +0800, John Garry wrote:
> From: Xiaofei Tan <tanxiaofei@xxxxxxxxxx>
>
> For some new boards with hip07 chipset we are required to
> set PHY config registers differently. The hw property which
> determines how to set these registers is in the PHY signal
> attenuation readings.
>
> This patch add an devicetree property, signal-attenuation, which
> is used to describe the signal attenuation of an board.
>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Signed-off-by: Xiaofei Tan <tanxiaofei@xxxxxxxxxx>
> Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/scsi/hisilicon-sas.txt | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/scsi/hisilicon-sas.txt b/Documentation/devicetree/bindings/scsi/hisilicon-sas.txt
> index df3bef7..bd32ecd 100644
> --- a/Documentation/devicetree/bindings/scsi/hisilicon-sas.txt
> +++ b/Documentation/devicetree/bindings/scsi/hisilicon-sas.txt
> @@ -53,6 +53,13 @@ Main node required properties:
> Optional main node properties:
> - hip06-sas-v2-quirk-amt : when set, indicates that the v2 controller has the
> "am-max-transmissions" limitation.
> + - signal-attenuation : array of 3 32-bit values, containing de-emphasis,
Needs a vendor prefix.
> + preshoot, and boost attenuation readings for the board. They
> + are used to describe the signal attenuation of the board. These
> + values' range is 7600 to 12400, and used to represent -24dB to
> + 24dB.
> + The formula is "y = (x-10000)/10000". For example, 10478
> + means 4.78dB.
>
> Example:
> sas0: sas@c1000000 {
> --
> 1.9.1
>
