netdev - Re: [PATCH net-next] net: phy: realtek: add suspend/resume callbacks for RTL8211B

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Message-ID: <20180524205302.GB6762@lunn.ch>
Date:   Thu, 24 May 2018 22:53:02 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Heiner Kallweit <hkallweit1@...il.com>
Cc:     David Miller <davem@...emloft.net>,
        Realtek linux nic maintainers <nic_swsd@...ltek.com>,
        Hau <hau@...ltek.com>, Florian Fainelli <f.fainelli@...il.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Kevin Hao <haokexin@...il.com>
Subject: Re: [PATCH net-next] net: phy: realtek: add suspend/resume callbacks
 for RTL8211B

On Thu, May 24, 2018 at 10:40:12PM +0200, Heiner Kallweit wrote:
> Add RTL8211B suspend / resume callbacks.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
> ---
> This patch is based on my knowledge of the r8169 driver, and on some
> guessing. Therefore I'd appreciate a confirmation from Realtek.
> 
> The integrated PHY in some chips supported by the r8169 driver uses
> a special sequence for power-down/-up. I have a board with a RTL8168D
> network chip (one of the chips using the special sequence) and there
> the PHY identifies as RTL8211B. So my guess is that this applies also
> to external RTL8211B PHY's.
> 
> A hint for RTL8211B requiring a special sequence is that no suspend/
> resume callbacks are defined yet in the Realtek PHY driver.
> Last but not least the non-standard usage of register MII_MMD_DATA
> is in line with the description of patch 0231b1a074c6.
> ("net: phy: realtek: Use the dummy stubs for MMD register access for rtl8211b")
> ---
>  drivers/net/phy/realtek.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
> index 9f48ecf9c..082fb40c6 100644
> --- a/drivers/net/phy/realtek.c
> +++ b/drivers/net/phy/realtek.c
> @@ -145,6 +145,20 @@ static int rtl8211f_config_init(struct phy_device *phydev)
>  	return phy_modify_paged(phydev, 0xd08, 0x11, RTL8211F_TX_DELAY, val);
>  }
>  
> +static int rtl8211b_suspend(struct phy_device *phydev)
> +{
> +	phy_write(phydev, MII_MMD_DATA, BIT(9));

Hi Heiner

Using it like this suggests it is not actually MMD_DATA, it is
something else which just happens to use the same address as the
optional MMD_DATA. To make this clearer, it would be good to add
#defines for both the register address and this BIT(9). Is there any
vendor code you know of which might give you a clue for appropriate
names?

I guess this device also does not support EEE? Does phy_init_eee()
correctly figure this out? Is there a chance calling phy_init_eee()
might trigger a suspend?

       Andrew