RE: [PATCH 2/2] net: dsa: b53: mdio: add support for BCM53134

[Paul Geurts]

> -----Original Message-----
> From: Florian Fainelli <f.fainelli@xxxxxxxxx>
> Sent: donderdag 23 maart 2023 17:43
> To: Álvaro Fernández Rojas <noltari@xxxxxxxxx>; Paul Geurts
> <paul.geurts@xxxxxxxxxxxxxxxxxxxxxxxxx>; jonas.gorski@xxxxxxxxx;
> andrew@xxxxxxx; olteanv@xxxxxxxxx; davem@xxxxxxxxxxxxx;
> edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx;
> robh+dt@xxxxxxxxxx; krzysztof.kozlowski+dt@xxxxxxxxxx;
> netdev@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH 2/2] net: dsa: b53: mdio: add support for BCM53134
> 
> On 3/23/23 05:18, Álvaro Fernández Rojas wrote:
> > From: Paul Geurts <paul.geurts@xxxxxxxxxxxxxxxxxxxxxxxxx>
> >
> > Add support for the BCM53134 Ethernet switch in the existing b53 dsa
> driver.
> > BCM53134 is very similar to the BCM58XX series.
> >
> > Signed-off-by: Paul Geurts <paul.geurts@xxxxxxxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Álvaro Fernández Rojas <noltari@xxxxxxxxx>
> > ---
> >   drivers/net/dsa/b53/b53_common.c | 53
> +++++++++++++++++++++++++++++++-
> >   drivers/net/dsa/b53/b53_mdio.c   |  5 ++-
> >   drivers/net/dsa/b53/b53_priv.h   |  9 +++++-
> >   3 files changed, 64 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/dsa/b53/b53_common.c
> > b/drivers/net/dsa/b53/b53_common.c
> > index 1f9b251a5452..aaa0813e6f59 100644
> > --- a/drivers/net/dsa/b53/b53_common.c
> > +++ b/drivers/net/dsa/b53/b53_common.c
> > @@ -1282,6 +1282,42 @@ static void b53_adjust_link(struct dsa_switch
> *ds, int port,
> >   	if (is63xx(dev) && port >= B53_63XX_RGMII0)
> >   		b53_adjust_63xx_rgmii(ds, port, phydev->interface);
> >
> > +	if (is53134(dev) && phy_interface_is_rgmii(phydev)) {
> 
> Why is not this in the same code block as the one for the is531x5() device like
> this:
> 
> diff --git a/drivers/net/dsa/b53/b53_common.c
> b/drivers/net/dsa/b53/b53_common.c
> index 59cdfc51ce06..1c64b6ce7e78 100644
> --- a/drivers/net/dsa/b53/b53_common.c
> +++ b/drivers/net/dsa/b53/b53_common.c
> @@ -1235,7 +1235,7 @@ static void b53_adjust_link(struct dsa_switch *ds,
> int port,
>                                tx_pause, rx_pause);
>          b53_force_link(dev, port, phydev->link);
> 
> -       if (is531x5(dev) && phy_interface_is_rgmii(phydev)) {
> +       if ((is531x5(dev) || is53134(dev)) &&
> phy_interface_is_rgmii(phydev)) {
>                  if (port == dev->imp_port)
>                          off = B53_RGMII_CTRL_IMP;
>                  else
> 
> Other than that, LGTM!
> --
> Florian

I think the only reason is that the BCM53134 does not support the
RGMII_CTRL_TIMING_SEL bit, which is set in the original block. I agree
Putting a if statement around
rgmii_ctrl |= RGMII_CTRL_TIMING_SEL;
would prevent a lot of code duplication. _however_, after looking at it again,
I don’t think the device does not support the bit. When looking at the datasheet,
The same bit in the this register is called BYPASS_2NS_DEL. It's very uncommon
For Broadcom to make such a change in the register interface, so maybe they
Just renamed it. Do you think this could be the same bit?

---
Paul