Re: [PATCH v9 1/2] dt-bindings: ufs: Document static TX Equalization settings properties

[Krzysztof Kozlowski <krzk@kernel.org>]

On 15/06/2026 15:28, Can Guo wrote:
> UFS v5.0/UFSHCI v5.0 adds HS-G6 support (46.6 Gbps/lane) via UniPro
> v3.0 and M-PHY v6.0. These specs define TX Equalization for all
> High-Speed Gears (not only HS-G6) to compensate channel loss and
> improve signal integrity at high speed.
> 
> For HS-G6, M-PHY uses PAM4 1b1b line coding. Pre-Coding may also be
> required depending on channel characteristics.
> 
> Document vendor-neutral properties in ufs-common.yaml:
> - txeq-preshoot-g[1-6]
> - txeq-deemphasis-g[1-6]
> - tx-precode-enable-g6
> 
> Values are per-lane Host/Device tuples (2 values for x1, 4 values for
> x2). PreShoot/DeEmphasis range from 0..7, and Precode is 0/1.
> 
> These are board-specific signal-integrity tuning values. They depend on
> channel SI/PHY characterization and validation (host PHY, device PHY,
> package, and board routing), and are determined by HW/PHY designers.
> 
> Although UFSHCI v5.0 supports TX Equalization Training via UniPro v3.0,
> which allows host software to determine optimal TX Equalization at
> runtime, static board-specific TX Equalization settings in the Device
> Tree are still necessary because:
> - TX Equalization Training is not supported for HS-G3 and below
> - TX Equalization Training is disabled on some platforms
> 
> Signed-off-by: Can Guo <can.guo@oss.qualcomm.com>
> ---
>  .../devicetree/bindings/ufs/ufs-common.yaml   | 58 +++++++++++++++++++
>  1 file changed, 58 insertions(+)

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

Best regards,
Krzysztof