Messages in this thread | | | Subject | Re: [PATCH] net: ethernet: fsl: don't en/disable refclk on open/close | From | Richard Leitner <> | Date | Mon, 23 Oct 2017 01:01:46 +0200 |
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On 10/23/2017 12:48 AM, Florian Fainelli wrote> On 10/22/2017 03:30 PM, Richard Leitner wrote: >> On 10/22/2017 08:31 PM, Florian Fainelli wrote: >>> On 10/22/2017 06:11 AM, Richard Leitner wrote:
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>> Andrew Lunn suggested to make the PHY driver a clock driver and let it >> export the refclk... But IMHO that "feels" a bit strange. Due to the >> fact in our case the clock is generated by the SoC and the PHY is an >> external chip which only consumes it. > > It depends which *MII mode you use. Unless you are using reverse MII, > the PHY supplies the RX clock and the MAC supplies the RX clock, so > solving this for all modes becomes quite tricky. Andrew's suggestion > makes sense, but considering that the MAC and PHY need to be connected > to each other, it may be tricky to request the PHY's clock before you > actually attached to the PHY... >> >> But back to this patch: Is it OK the way it fixes the issue? > > Fugang and Andrew probably know this hardware a lot better, I would have > to look at the code path a bit more to understand if an alternative > solution is possible. It sounds like your patch could create a power > consumption regression, so maybe add a check for the PHY ID that is > problematic by doing something like: > > if (priv->phydev->drv && priv->phydev->drv->phy_id == XXXX_XXXX) where > XXXX_XXXX is the LAN870 PHY ID (obtained from MII register 2 & 3).
I already had a patch which does this check and triggers a reset of the PHY after the refclk was enabled (in fec_enet_clk_enable) in case the phy_id matches. This would IMHO avoid all power consumption regressions... It was something like:
switch (priv->phydev->drv->phy_id) { case XXXX: case XXXX: ret = fec_reset_phy(ndev); if (ret) goto failed_reset; if (ndev->phydev) { ret = phy_init_hw(ndev->phydev); if (ret) goto failed_reset; } }
Would that be better?
Basically I'm fine with any kind of solution... It's up to you guys... You're the experts ;-)
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