[PATCH 3/4] ARM: dts: imx6ul-14x14-evk: Describe the KSZ8081 reset

[Joakim Zhang]

Hi Fabio, Andrew,

After applying Fabio's patch to support PHY hardware reset. I found i.MX6UL 14x14 EVK board is broken in latest upstream kernel.
	ARM: dts: imx6ul-14x14-evk: Enable the GPIO expander
	ARM: dts: imx6ul-14x14-evk: Describe the KSZ8081 reset

Case 1:
root at imx6ul7d:~# ifconfig eth0 down
root at imx6ul7d:~# [  279.386551] fec 2188000.ethernet eth1: Link is Down
After down eth0, eth1 would down, then eth1 can't be used any more.

The same behavior for another ethernet,
root at imx6ul7d:~# ifconfig eth1 down
root at imx6ul7d:~# [  118.106726] fec 20b4000.ethernet eth0: Link is Down
After down eth1, eth0 would down, then eth0 can't be used any more.

Case 2:
[    9.182109] Micrel KSZ8081 or KSZ8091 20b4000.ethernet-1:01: attached PHY driver (mii_bus:phy_addr=20b4000.ethernet-1:01, irq=POLL)
[    9.309462] Micrel KSZ8081 or KSZ8091 20b4000.ethernet-1:02: attached PHY driver (mii_bus:phy_addr=20b4000.ethernet-1:02, irq=POLL)
[   11.397952] fec 2188000.ethernet eth1: Link is Up - 100Mbps/Full - flow control rx/tx
[   11.414343] IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready
[   11.429546] Sending DHCP requests ., OK
[   11.596850] IP-Config: Got DHCP answer from 10.193.102.252, my address is 10.193.102.87
[   11.605689] IP-Config: Complete:
[   11.609595]      device=eth1, hwaddr=00:04:9f:04:3e:92, ipaddr=10.193.102.87, mask=255.255.255.0, gw=10.193.102.254
[   11.620621]      host=10.193.102.87, domain=ap.freescale.net, nis-domain=(none)
[   11.628118]      bootserver=0.0.0.0, rootserver=10.193.108.176, rootpath=
[   11.628230]      nameserver0=165.114.89.4, nameserver1=134.27.184.42
[   11.697259] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[   11.731941] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[   11.742445] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2
[   11.751605] platform regulatory.0: Falling back to sysfs fallback for: regulatory.db
[   11.762730] ALSA device list:
[   11.765818]   #0: mx6ul-wm8960
[   12.433430] fec 2188000.ethernet eth1: Link is Down

It is broken when mounting NFS, per the log, we can see that eth0 and eth1 is up, and when it down the eth0, eth1 would link down too.

The root cause should be down one ethernet would affect another ethernet when it calling mdio_device_reset to pull Q1 or Q2 to low. After the ethernet down, I check Q1 and Q2 is 1.2V.
I also check the code, each PHY has one phy_device, containing it's own mdio_device. So each PHY should be independent, when do mdio device level hw reset, it should not affect others.
Could you give some hints? There is no any process after one debugging. Thanks a lot.

Best Regards,
Joakim Zhang


> -----Original Message-----
> From: Fabio Estevam <festevam at gmail.com>
> Sent: 2021年1月8日 7:51
> To: shawnguo at kernel.org
> Cc: kernel at pengutronix.de; dl-linux-imx <linux-imx at nxp.com>;
> andrew at lunn.ch; linux-arm-kernel at lists.infradead.org; Fabio Estevam
> <festevam at gmail.com>
> Subject: [PATCH 3/4] ARM: dts: imx6ul-14x14-evk: Describe the KSZ8081 reset
> 
> There are two KSZ8081 on the imx6ul-14x14-evk: one has the reset line
> controlled by the Q1 output of the 74LV595PW expander, and the other by the
> Q2 output.
> 
> The KSZ8081 datasheet states that the tsr parameter (Stable supply voltage
> (VDDIO, VDDA_3.3) to reset high) to be 10ms minimum and "After the
> de-assertion of reset, wait a minimum of 100 µs before starting programming
> on the MIIM (MDC/MDIO) interface."
> 
> Describe these parameters in the devicetree.
> 
> Signed-off-by: Fabio Estevam <festevam at gmail.com>
> ---
>  arch/arm/boot/dts/imx6ul-14x14-evk.dtsi | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/imx6ul-14x14-evk.dtsi
> b/arch/arm/boot/dts/imx6ul-14x14-evk.dtsi
> index 8bf845afd166..ac2ec96f54e7 100644
> --- a/arch/arm/boot/dts/imx6ul-14x14-evk.dtsi
> +++ b/arch/arm/boot/dts/imx6ul-14x14-evk.dtsi
> @@ -175,6 +175,10 @@
>  			micrel,led-mode = <1>;
>  			clocks = <&clks IMX6UL_CLK_ENET_REF>;
>  			clock-names = "rmii-ref";
> +			reset-gpios = <&gpio_spi 1 GPIO_ACTIVE_LOW>;
> +			reset-assert-us = <10000>;
> +			reset-deassert-us = <100>;
> +
>  		};
> 
>  		ethphy1: ethernet-phy at 1 {
> @@ -183,6 +187,9 @@
>  			micrel,led-mode = <1>;
>  			clocks = <&clks IMX6UL_CLK_ENET2_REF>;
>  			clock-names = "rmii-ref";
> +			reset-gpios = <&gpio_spi 2 GPIO_ACTIVE_LOW>;
> +			reset-assert-us = <10000>;
> +			reset-deassert-us = <100>;
>  		};
>  	};
>  };
> --
> 2.17.1