netdev - Re: [PATCH net-next 2/2] net: phy: broadcom: Do not modify LED configuration for SFP module PHYs

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Date:   Sat, 13 Feb 2021 03:41:12 +0200
From:   Vladimir Oltean <olteanv@...il.com>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     Robert Hancock <robert.hancock@...ian.com>, andrew@...n.ch,
        hkallweit1@...il.com, davem@...emloft.net, kuba@...nel.org,
        linux@...linux.org.uk, bcm-kernel-feedback-list@...adcom.com,
        netdev@...r.kernel.org
Subject: Re: [PATCH net-next 2/2] net: phy: broadcom: Do not modify LED
 configuration for SFP module PHYs

On Fri, Feb 12, 2021 at 05:17:53PM -0800, Florian Fainelli wrote:
> On 2/12/2021 4:28 PM, 'Robert Hancock' via BCM-KERNEL-FEEDBACK-LIST,PDL
> wrote:
> > bcm54xx_config_init was modifying the PHY LED configuration to enable link
> > and activity indications. However, some SFP modules (such as Bel-Fuse
> > SFP-1GBT-06) have no LEDs but use the LED outputs to control the SFP LOS
> > signal, and modifying the LED settings will cause the LOS output to
> > malfunction. Skip this configuration for PHYs which are bound to an SFP
> > bus.

That would be me, sorry.

> > Signed-off-by: Robert Hancock <robert.hancock@...ian.com>
> > ---
> >  drivers/net/phy/broadcom.c | 26 +++++++++++++++++---------
> >  1 file changed, 17 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
> > index 78542580f2b2..81a5721f732a 100644
> > --- a/drivers/net/phy/broadcom.c
> > +++ b/drivers/net/phy/broadcom.c
> > @@ -12,6 +12,7 @@
> >  
> >  #include "bcm-phy-lib.h"
> >  #include <linux/module.h>
> > +#include <linux/netdevice.h>
> >  #include <linux/phy.h>
> >  #include <linux/brcmphy.h>
> >  #include <linux/of.h>
> > @@ -365,18 +366,25 @@ static int bcm54xx_config_init(struct phy_device *phydev)
> >  
> >  	bcm54xx_phydsp_config(phydev);
> >  
> > -	/* Encode link speed into LED1 and LED3 pair (green/amber).
> > +	/* For non-SFP setups, encode link speed into LED1 and LED3 pair
> > +	 * (green/amber).
> >  	 * Also flash these two LEDs on activity. This means configuring
> >  	 * them for MULTICOLOR and encoding link/activity into them.
> > +	 * Don't do this for devices that may be on an SFP module, since
> > +	 * some of these use the LED outputs to control the SFP LOS signal,
> > +	 * and changing these settings will cause LOS to malfunction.
> >  	 */
> > -	val = BCM5482_SHD_LEDS1_LED1(BCM_LED_SRC_MULTICOLOR1) |
> > -		BCM5482_SHD_LEDS1_LED3(BCM_LED_SRC_MULTICOLOR1);
> > -	bcm_phy_write_shadow(phydev, BCM5482_SHD_LEDS1, val);
> > -
> > -	val = BCM_LED_MULTICOLOR_IN_PHASE |
> > -		BCM5482_SHD_LEDS1_LED1(BCM_LED_MULTICOLOR_LINK_ACT) |
> > -		BCM5482_SHD_LEDS1_LED3(BCM_LED_MULTICOLOR_LINK_ACT);
> > -	bcm_phy_write_exp(phydev, BCM_EXP_MULTICOLOR, val);
> > +	if (!phydev->sfp_bus &&
> > +	    (!phydev->attached_dev || !phydev->attached_dev->sfp_bus)) {
> > +		val = BCM5482_SHD_LEDS1_LED1(BCM_LED_SRC_MULTICOLOR1) |
> > +			BCM5482_SHD_LEDS1_LED3(BCM_LED_SRC_MULTICOLOR1);
> > +		bcm_phy_write_shadow(phydev, BCM5482_SHD_LEDS1, val);
> > +
> > +		val = BCM_LED_MULTICOLOR_IN_PHASE |
> > +			BCM5482_SHD_LEDS1_LED1(BCM_LED_MULTICOLOR_LINK_ACT) |
> > +			BCM5482_SHD_LEDS1_LED3(BCM_LED_MULTICOLOR_LINK_ACT);
> > +		bcm_phy_write_exp(phydev, BCM_EXP_MULTICOLOR, val);
> 
> Not sure I can come up with a better solution but this should probably
> be made conditional upon the specific SFP module, or a set of specific
> SFP modules, whether we can convey those details via a Device Tree
> property or by doing a SFP ID lookup.
> 
> Acked-by: Florian Fainelli <f.fainelli@...il.com>

Not sure when is the last time I saw an SFP module with activity/link
LEDs, the patch was intended for a BCM5464R RJ45 twisted pair setup
which I still have.

What is the last thing that happened in PHY LED territory? I lost track
since Marek's RFC for offloading phy_led_triggers that didn't seem to
make any progress. I could try to explicitly request the activity LED to
blink on my board via device tree, if it helps.