From: Andrew Lunn <andrew@lunn.ch>
To: Sam Lewis <sam.vr.lewis@gmail.com>
Cc: steve.glendinning@shawell.net, UNGLinuxDriver@microchip.com,
netdev@vger.kernel.org
Subject: Re: PROBLEM: smsc95xx loses config on link down/up
Date: Mon, 2 Dec 2019 14:46:06 +0100 [thread overview]
Message-ID: <20191202134606.GA1234@lunn.ch> (raw)
In-Reply-To: <CA+ZLECteuEZJM_4gtbxiEAAKbKnJ_3UfGN4zg_m2EVxk_9=WiA@mail.gmail.com>
On Thu, Nov 28, 2019 at 06:19:14PM +1100, Sam Lewis wrote:
> I'm using a LAN9514 chip in my embedded Linux device and have noticed
> that changing Ethernet configuration (with ethtool for example) does
> not persist after putting the link up.
Hi Sam
Did you ever get a reply to this?
> I've hacked through the driver code (without really knowing what I'm
> doing, just adding various print statements) and I think this happens
> because setting a link up causes the `smsc95xx_reset` function to be
> called which seems to clear all configuration through:
>
> 1) Doing a PHY reset (with `smsc95xx_write_reg(dev, PM_CTRL, PM_CTL_PHY_RST_)`)
> 2) Doing (another?) PHY reset (with `smsc95xx_mdio_write(dev->net,
> dev->mii.phy_id, MII_BMCR, BMCR_RESET)`)
In general, BMCR_RESET does not clear configuration registers such as
auto-neg etc. It generally just gives the PHY a kick to restart itself
using the configuration as set. So i would initially point a finger at
PM_CTL_PHY_RST_.
Is there a full datasheet somewhere?
You might want to think about using PM_CTL_PHY_RST_ once during probe,
and only BMCR_RESET in open.
Andrew
next prev parent reply other threads:[~2019-12-02 13:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-28 7:19 PROBLEM: smsc95xx loses config on link down/up Sam Lewis
2019-12-02 13:46 ` Andrew Lunn [this message]
2019-12-03 6:19 ` Sam Lewis
2019-12-03 13:27 ` Andrew Lunn
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