Thread (1 message) 1 message, 1 author, 2016-08-18

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

From: Rob Herring <hidden>
Date: 2016-08-18 19:27:14

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