netdev - Re: [PATCH v4 net-next] net: phy: Add Edge-rate driver for Microsemi PHYs.

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Message-ID: <20161003072043.GA24259@microsemi.com>
Date:   Mon, 3 Oct 2016 12:50:45 +0530
From:   Raju Lakkaraju <Raju.Lakkaraju@...rosemi.com>
To:     Andrew Lunn <andrew@...n.ch>
CC:     <netdev@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <f.fainelli@...il.com>, <Allan.Nielsen@...rosemi.com>
Subject: Re: [PATCH v4 net-next] net: phy: Add Edge-rate driver for Microsemi
 PHYs.

Hi Andrew,

Thank you for code review and valuable comments.

On Wed, Sep 28, 2016 at 06:16:53PM +0200, Andrew Lunn wrote:
> EXTERNAL EMAIL
> 
> 
> > +Optional properties:
> > +- vsc8531,vddmac     : The vddmac in mV.
> > +- vsc8531,edge-slowdown      : % the edge should be slowed down relative to
> > +                       the fastest possible edge time. Native sign
> > +                       need not enter.
> > +                       Edge rate sets the drive strength of the MAC
> > +                       interface output signals.  Changing the drive
> > +                       strength will affect the edge rate of the output
> > +                       signal.  The goal of this setting is to help
> > +                       reduce electrical emission (EMI) by being able
> > +                       to reprogram drive strength and in effect slow
> > +                       down the edge rate if desired.  Table 5 shows the
> 
> Hi Raju
> 
> There is no table five here? Is that a reference to a data sheet
> table?
> 

I accepted your comment.
It was typo. It should be Table 1.
Yes. In datasheet Edge rate control is Table 5.

> > +Example:
> > +
> > +        vsc8531_0: ethernet-phy@0 {
> > +                compatible = "ethernet-phy-id0007.0570";
> > +                vsc8531,vddmac               = /bits/ 16 <MSCC_VDDMAC_3300>;
> > +                vsc8531,edge-slowdown        = /bits/ 8  <17>;
> 
> No, real values please:
> 
>                 vsc8531,vddmac          = <2000>;
>                 vsc8531,edge-slowdown   = <21>;
> 
> The driver should then do the maths to figure out the nearest magic
> value to write to the register, or complain the settings are out of
> range with an -EINVAL.
> 
> FYI: No floating point maths are allowed in the kernel.
> 

I accepted your review comment. I will change and resend again.

>    Andrew

---
Thanks,
Raju.