linux-kernel - Re: [PATCH net-next v2 3/3] net: phy: broadcom: Allow BCM54210E to configure APD

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Date:   Tue, 2 Mar 2021 19:37:34 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>
Cc:     netdev@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Michael Chan <mchan@...adcom.com>,
        "open list:BROADCOM ETHERNET PHY DRIVERS" 
        <bcm-kernel-feedback-list@...adcom.com>,
        open list <linux-kernel@...r.kernel.org>, michael@...le.cc
Subject: Re: [PATCH net-next v2 3/3] net: phy: broadcom: Allow BCM54210E to
 configure APD



On 2/14/2021 8:29 PM, Florian Fainelli wrote:
> 
> 
> On 2/13/2021 2:42 AM, Vladimir Oltean wrote:
>> On Fri, Feb 12, 2021 at 07:46:32PM -0800, Florian Fainelli wrote:
>>> BCM54210E/BCM50212E has been verified to work correctly with the
>>> auto-power down configuration done by bcm54xx_adjust_rxrefclk(), add it
>>> to the list of PHYs working.
>>>
>>> While we are at it, provide an appropriate name for the bit we are
>>> changing which disables the RXC and TXC during auto-power down when
>>> there is no energy on the cable.
>>>
>>> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
>>> ---
>>
>> Reviewed-by: Vladimir Oltean <olteanv@...il.com>
>>
>>>  drivers/net/phy/broadcom.c | 8 +++++---
>>>  include/linux/brcmphy.h    | 2 +-
>>>  2 files changed, 6 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
>>> index 3ce266ab521b..91fbd26c809e 100644
>>> --- a/drivers/net/phy/broadcom.c
>>> +++ b/drivers/net/phy/broadcom.c
>>> @@ -193,6 +193,7 @@ static void bcm54xx_adjust_rxrefclk(struct phy_device *phydev)
>>>  	if (BRCM_PHY_MODEL(phydev) != PHY_ID_BCM57780 &&
>>>  	    BRCM_PHY_MODEL(phydev) != PHY_ID_BCM50610 &&
>>>  	    BRCM_PHY_MODEL(phydev) != PHY_ID_BCM50610M &&
>>> +	    BRCM_PHY_MODEL(phydev) != PHY_ID_BCM54210E &&
>>>  	    BRCM_PHY_MODEL(phydev) != PHY_ID_BCM54810 &&
>>>  	    BRCM_PHY_MODEL(phydev) != PHY_ID_BCM54811)
>>>  		return;
>>> @@ -227,9 +228,10 @@ static void bcm54xx_adjust_rxrefclk(struct phy_device *phydev)
>>>  		val |= BCM54XX_SHD_SCR3_DLLAPD_DIS;
>>>  
>>>  	if (phydev->dev_flags & PHY_BRCM_DIS_TXCRXC_NOENRGY) {
>>> -		if (BRCM_PHY_MODEL(phydev) == PHY_ID_BCM54810 ||
>>> -		    BRCM_PHY_MODEL(phydev) == PHY_ID_BCM54811)
>>> -			val |= BCM54810_SHD_SCR3_TRDDAPD;
>>> +		if (BRCM_PHY_MODEL(phydev) == PHY_ID_BCM54210E ||
>>> +		    BRCM_PHY_MODEL(phydev) == PHY_ID_BCM54810 ||
>>> +		    BRCM_PHY_MODEL(phydev) == PHY_ID_BCM54210E)
>>> +			val |= BCM54XX_SHD_SCR3_RXCTXC_DIS;
>>>  		else
>>>  			val |= BCM54XX_SHD_SCR3_TRDDAPD;
>>>  	}
>>> diff --git a/include/linux/brcmphy.h b/include/linux/brcmphy.h
>>> index 844dcfe789a2..16597d3fa011 100644
>>> --- a/include/linux/brcmphy.h
>>> +++ b/include/linux/brcmphy.h
>>> @@ -193,6 +193,7 @@
>>>  #define  BCM54XX_SHD_SCR3_DEF_CLK125	0x0001
>>>  #define  BCM54XX_SHD_SCR3_DLLAPD_DIS	0x0002
>>>  #define  BCM54XX_SHD_SCR3_TRDDAPD	0x0004
>>> +#define  BCM54XX_SHD_SCR3_RXCTXC_DIS	0x0100
>>
>> Curiously enough, my BCM5464R datasheet does say:
>>
>> The TXC and RXC outputs can be disabled during auto-power down by setting the “1000BASE-T/100BASE-TX/10BASE-T
>> Spare Control 3 Register (Address 1Ch, Shadow Value 00101),” bit 8 =1.
>>
>> but when I go to the definition of the register, bit 8 is hidden. Odd.
>>
>> How can I ensure that the auto power down feature is doing something?
> 
> I am trying to confirm what the expected power levels should be from the
> 54210E product engineer so I can give you an estimate of what you should
> see with and without while measure the PHY's regulators.

Took a while but for the 54210E reference board here are the numbers,
your mileage will vary depending on the supplies, regulator efficiency
and PCB design around the PHY obviously:

BMCR.PDOWN:			86.12 mW
auto-power down:		77.84 mW
auto-power-down, DLL disabled:  30.83 mW
IDDQ-low power:			 9.85 mW (requires a RESETn toggle)
IDDQ with soft recovery:	10.75 mW

Interestingly, the 50212E that I am using requires writing the PDOWN bit
and only that bit (not a RMW) in order to get in a correct state, both
LEDs keep flashing when that happens, fixes coming.

When net-next opens back up I will submit patches to support IDDQ with
soft recovery since that is clearly much better than the standard power
down and it does not require a RESETn toggle.
-- 
Florian