linux-kernel - Re: [PATCH net-next v3 2/4] phylib: add reset after clk enable support

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Date:   Tue, 5 Dec 2017 18:34:07 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Richard Leitner <dev@...l1n.net>
Cc:     robh+dt@...nel.org, mark.rutland@....com, fugang.duan@....com,
        f.fainelli@...il.com, frowand.list@...il.com, davem@...emloft.net,
        geert+renesas@...der.be, sergei.shtylyov@...entembedded.com,
        baruch@...s.co.il, david.wu@...k-chips.com, lukma@...x.de,
        netdev@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, richard.leitner@...data.com
Subject: Re: [PATCH net-next v3 2/4] phylib: add reset after clk enable
 support

On Tue, Dec 05, 2017 at 02:25:58PM +0100, Richard Leitner wrote:
> From: Richard Leitner <richard.leitner@...data.com>
> 
> Some PHYs need the refclk to be a continuous clock. Therefore they don't
> allow turning it off and on again during operation. Nonetheless such a
> clock switching is performed by some ETH drivers (namely FEC [1]) for
> power saving reasons. An example for an affected PHY is the
> SMSC/Microchip LAN8720 in "REF_CLK In Mode".
> 
> In order to provide a uniform method to overcome this problem this patch
> adds a new phy_driver flag (PHY_RST_AFTER_CLK_EN) and corresponding
> function phy_reset_after_clk_enable() to the phylib. These should be
> used to trigger reset of the PHY after the refclk is switched on again.
> 
> This patch depends on the "phylib: Add device reset GPIO support" patch
> submitted by Geert Uytterhoeven/Sergei Shtylyov [2].
> 
> [1] commit e8fcfcd5684a ("net: fec: optimize the clock management to save power")
> [2] https://patchwork.kernel.org/patch/10090149/
> 
> Signed-off-by: Richard Leitner <richard.leitner@...data.com>

Hi Richard

Same comment about moving text below the ---

Reviewed-by: Andrew Lunn <andrew@...n.ch>

    Andrew