Re: [PATCH] usb: phy: mxs: Add DT bindings to configure TX settings

[Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Tue, Aug 16, 2016 at 06:31:48PM -0400, Jaret Cantu wrote:
> The TX settings can be calibrated for particular hardware.  The
> phy is reset by Linux, so this cannot be handled by the bootloader.
> 
> The TRM mentions that the maximum resistance should be used for the
> DN/DP calibration in order to pass USB certification.
> 
> The values for the TX registers are poorly described in the TRM.
> The meanings of the register values were taken from another
> NXP-provided document:
> https://community.nxp.com/message/566147#comment-566912
> 
> Signed-off-by: Jaret Cantu <jaret.cantu-jEh4hwF5bVhBDgjK7y7TUQ@public.gmane.org>
> ---
> v4. Corrected tx-d-cal register value by rounding up.
>     Changed Freescale web site reference to NXP.
> 
> v3. Added unit suffix (-ohms) to tx-cal-45-d*
> 
> v2. Copying devicetree list
>     Removed prettifying extra whitespace
>     Removed unnecessary register rewrite on resume
>     Use min and max constants for clarity
> 
>  .../devicetree/bindings/phy/mxs-usb-phy.txt        |   10 ++++

Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>

>  drivers/usb/phy/phy-mxs-usb.c                      |   61 ++++++++++++++++++++
>  2 files changed, 71 insertions(+)
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