From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v8 net-next] net: phy: Add Edge-rate driver for Microsemi PHYs. Date: Mon, 10 Oct 2016 07:50:07 -0500 Message-ID: <20161010125007.GA24902@rob-hp-laptop> References: <1475667578-20799-1-git-send-email-Raju.Lakkaraju@microsemi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1475667578-20799-1-git-send-email-Raju.Lakkaraju-dzo6w/eZyo2tG0bUXCXiUA@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Raju Lakkaraju Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, Allan.Nielsen-dzo6w/eZyo2tG0bUXCXiUA@public.gmane.org, andrew-g2DYL2Zd6BY@public.gmane.org List-Id: devicetree@vger.kernel.org On Wed, Oct 05, 2016 at 05:09:38PM +0530, Raju Lakkaraju wrote: > From: Raju Lakkaraju > > Edge-rate: > As system and networking speeds increase, a signal's output transition, > also know as the edge rate or slew rate (V/ns), takes on greater importance > because high-speed signals come with a price. That price is an assortment of > interference problems like ringing on the line, signal overshoot and > undershoot, extended signal settling times, crosstalk noise, transmission > line reflections, false signal detection by the receiving device and > electromagnetic interference (EMI) -- all of which can negate the potential > gains designers are seeking when they try to increase system speeds through > the use of higher performance logic devices. The fact is, faster signaling > edge rates can cause a higher level of electrical noise or other type of > interference that can actually lead to slower line speeds and lower maximum > system frequencies. This parameter allow the board designers to change the > driving strange, and thereby change the EMI behavioral. > > Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree. > > Tested on Beaglebone Black with VSC 8531 PHY. > > Signed-off-by: Raju Lakkaraju > > --- > All the review comments updated and resending for review. > > Change set: > v1: > - Initial version of Edge-rate driver add by using IOCTL. > v2: > - Changed edge-rate parameter to Device Tree with magic number. > v3: > - Added Device Tree documentati0n and edge-rate parameter table. > Added probe function initialize the vsc8531 private data structure. > v4: > - As per review comment, Device Tree parameters (vddmac, edge-slowdown) > added. > v5: > - As per review comment, Device Tree Document parameters (vddmac, > edge-slowdown) real numbers added. Table number changed from 5 to 1. > v6: > - As per review comment, Removed Device Tree header file. Removed MACROs > and add ARRAYSIZE > v7: > - As per review comment, Removed '-'s (minus) sign in Edge rate table. > v8: > - As per review comment, Added DT vddmac, slowdown value error check. > > --- > > .../devicetree/bindings/net/mscc-phy-vsc8531.txt | 22 +++---- Acked-by: Rob Herring > drivers/net/phy/mscc.c | 69 +++++++++++++++------- > include/dt-bindings/net/mscc-phy-vsc8531.h | 21 ------- > 3 files changed, 59 insertions(+), 53 deletions(-) > delete mode 100644 include/dt-bindings/net/mscc-phy-vsc8531.h -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html