netdev - Re: DSA mv88e6xxx

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Date:   Fri, 3 Feb 2023 14:47:11 +0000
From:   "Valek, Andrej" <andrej.valek@...mens.com>
To:     "andrew@...n.ch" <andrew@...n.ch>
CC:     "vivien.didelot@...il.com" <vivien.didelot@...il.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: DSA mv88e6xxx_probe

On Fri, 2023-02-03 at 14:54 +0100, Andrew Lunn wrote:
> > > > This looks promising. So I have to just move the "reset-gpios" DTB
> > > > entry from switch to mdio section. But which driver handles it,
> > > > drivers/net/phy/mdio_bus.c,
> > > 
> > > Yes.
> > > 
> > > > > mdio {
> > > > >         #address-cells = <1>;
> > > > >         #size-cells = 0>;
> > > > while here is no compatible part... .
> > > 
> > > It does not need a compatible, because it is part of the FEC, and the
> > > FEC has a compatible. Remember this is device tree, sometimes you need
> > > to go up the tree towards the root to find the actual device with a
> > > compatible.
> > > 
> > >     Andrew
> > I tried put the "reset-gpios" and "reset-delay-us" into multiple mdio locations, but nothing has been working. DTB looks like that:
> > 
> > > &fec1 {
> > >         pinctrl-names = "default";
> > >         pinctrl-0 = <&pinctrl_fec1>;
> > >         phy-mode = "rgmii-id";
> > >         tx-internal-delay-ps = <2000>;
> > >         rx-internal-delay-ps = <2000>;
> > >         slaves = <1>;                   // use only one emac if
> > >         status = "okay";
> > >         mac-address = [ 00 00 00 00 00 00 ]; // Filled in by U-Boot
> > > 
> > >         // #### 3. try ####
> > >         //phy-reset-gpios = <&lsio_gpio0 13 GPIO_ACTIVE_LOW>;
> > >         //reset-delay-us = <10000>;
> > > 
> > >         fixed-link {
> > >                 speed = <1000>;
> > >                 full-duplex;
> > >         };
> > > 
> > >         mdio {
> > >                 #address-cells = <1>;
> > >                 #size-cells = <0>;
> > > 
> > >                 // 1. try
> > >                 reset-gpios = <&lsio_gpio0 13 GPIO_ACTIVE_LOW>;
> > >                 reset-delay-us = <10000>;
> 
> This looks like the correct location. Have you put a printk() after
> https://elixir.bootlin.com/linux/latest/source/drivers/net/phy/mdio_bus.c#L569
> to make sure it has found it?
> 
Yes, I put there multiple printk-s... .
> 	dev_info(&bus->dev, "device registered\n");
>
> 	mutex_init(&bus->mdio_lock);
> 	mutex_init(&bus->shared_lock);
>
> 	/* assert bus level PHY GPIO reset */
> 	gpiod = devm_gpiod_get_optional(&bus->dev, "reset", GPIOD_OUT_HIGH);
> 	dev_info(&bus->dev, "getting gpiod\n");
>
> 	if (IS_ERR(gpiod)) {
> 		err = dev_err_probe(&bus->dev, PTR_ERR(gpiod),
> 				    "mii_bus %s couldn't get reset GPIO\n",
> 				    bus->id);
> 		device_del(&bus->dev);
> 		return err;
> 	} else	if (gpiod) {
> 		dev_info(&bus->dev, "gpiod found\n");
> 		bus->reset_gpiod = gpiod;
> 		fsleep(bus->reset_delay_us);
> 		gpiod_set_value_cansleep(gpiod, 0);
> 		if (bus->reset_post_delay_us > 0)
> 			fsleep(bus->reset_post_delay_us);
> 	}
>
> 	if (bus->reset) {
> 		dev_info(&bus->dev, "reset found\n");
> 		err = bus->reset(bus);

And the output log looks:
> [    1.446095] mdio_bus fixed-0: device registered
> [    1.450698] mdio_bus fixed-0: getting gpiod
> [    1.494870] pps pps0: new PPS source ptp0
> [    1.505888] mdio_bus 5b040000.ethernet-1: device registered
> [    1.511552] mdio_bus 5b040000.ethernet-1: getting gpiod
> [    1.550705] pps pps0: new PPS source ptp0
> [    1.561203] mdio_bus 5b050000.ethernet-1: device registered
> [    1.566791] mdio_bus 5b050000.ethernet-1: getting gpiod
> ...
> [    2.568174] fec 5b050000.ethernet eth0: registered PHC device 0

Sp there are only a "device registered" and "getting gpiod" messages and nor "gpiod found" and "resed found".
So now the question is why it didn't find the reset in dtb, or where to place it.

Andrej

> You might also need a post reset delay. I'm not sure the device will
> answer if it is still busy reading the EEPROM. Which is why the
> mv88e6xxx hardware reset does some polling before continuing.
> 
>           Andrew