From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C11FC76188 for ; Wed, 5 Apr 2023 12:15:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237738AbjDEMPS (ORCPT ); Wed, 5 Apr 2023 08:15:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53702 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237682AbjDEMPR (ORCPT ); Wed, 5 Apr 2023 08:15:17 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 283A63C38 for ; Wed, 5 Apr 2023 05:15:16 -0700 (PDT) Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=irc.pengutronix.de) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1pk22T-0003WC-Id; Wed, 05 Apr 2023 14:14:57 +0200 Message-ID: <3f7257ee36dc44f162a87281c8279fd5bad91dea.camel@pengutronix.de> Subject: Re: [PATCH 1/2] dt-bindings: phy: imx8mq-usb: add phy tuning properties From: Johannes Zink To: Krzysztof Kozlowski , vkoul@kernel.org, kishon@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, linux-imx@nxp.com, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, jun.li@nxp.com, haibo.chen@nxp.com, linux-phy@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org Date: Wed, 05 Apr 2023 14:14:30 +0200 In-Reply-To: <5398cbe0-c681-5dd7-0b3e-3a586cc4915f@linaro.org> References: <20230405112118.1256151-1-j.zink@pengutronix.de> <20230405112118.1256151-2-j.zink@pengutronix.de> <5398cbe0-c681-5dd7-0b3e-3a586cc4915f@linaro.org> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.3-1+deb11u1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2a0a:edc0:0:900:1d::77 X-SA-Exim-Mail-From: j.zink@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Krysztof, thanks for your review, please find my questions below. On Wed, 2023-04-05 at 13:51 +0200, Krzysztof Kozlowski wrote: > [snip] > >        A phandle to the regulator for USB VBUS. > >   > > +  fsl,phy-tx-vref-tune: > > +    description: > > +      HS DC Voltage level adjustment > > "Level" in what units? > The datasheet just shows percent, ranging from -6 to +24%, in 2% increments. What unit would you suggest? > > +    $ref: /schemas/types.yaml#/definitions/uint32 > > +    enum: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, > > 16] > > + > > +  fsl,phy-tx-rise-tune: > > +    description: > > +      HS Transmitter Rise/Fall Time Adjustment > > +    $ref: /schemas/types.yaml#/definitions/uint32 > > +    enum: [0, 1, 2, 3] > > + > > +  fsl,phy-tx-preemp-amp-tune: > > +    description: > > +      HS Transmitter Pre-Emphasis Current Control > > If this is current then use standard unit suffixes. According to the datasheet this is in "unit amonts" of 600uA, basically 0x600uA, 1x600uA etc. Should I just suffix it with uA then? > > > +    $ref: /schemas/types.yaml#/definitions/uint32 > > +    enum: [0, 1, 2, 3] > > + > > +  fsl,phy-tx-vboost-level: > > +    description: > > +      TX Voltage Boost Level > > +    $ref: /schemas/types.yaml#/definitions/uint32 > > +    enum: [0, 2, 3] > > + > > +  fsl,phy-comp-dis-tune: > > +    description: > > +      Disconnect Threshold Adjustment > > +    $ref: /schemas/types.yaml#/definitions/uint32 > > +    enum: [0, 1, 2, 3, 4, 5, 6, 7] > > + > > +  fsl,phy-pcs-tx-deemph-3p5db: > > +    description: > > +      TX De-Emphasis at 3.5 dB > > +    $ref: /schemas/types.yaml#/definitions/uint32 > > + > > +  fsl,phy-pcs-tx-swing-full: > > +    description: > > +      TX Amplitude > > I have feeling you just pasted here short titles from datasheet. They > are not that helpful. ack, I will add some more text from the register description, since I have no other source of information on these. Best regards Johannes > > > > Best regards, > Krzysztof > > > -- Pengutronix e.K. | Johannes Zink | Steuerwalder Str. 21 | https://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686| Fax: +49-5121-206917-5555 |