RE: [PATCH AUTOSEL 4.19 45/73] net: phy: micrel: add toggling phy reset if PHY is not attached

Yoshihiro Shimoda
2018-12-13T04:44:49Z

Hi,

> From: Sasha Levin <sashal@kernel.org>, Sent: Thursday, December 13, 2018 1:28 PM
>
> From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
>
> [ Upstream commit 8c85f4b81296a530b8af2796c110fa482ac42d4f ]

Since this upstream commit are reverted by the following commit,
we should not backport it.

---
commit 7b566f70e1bf65b189b66eb3de6f431c30f7dff2
Author: David S. Miller <davem@davemloft.net>
Date: Tue Dec 4 08:47:44 2018 -0800

phy: Revert toggling reset changes.

This reverts:

ef1b5bf506b1 ("net: phy: Fix not to call phy_resume() if PHY is not attached
8c85f4b81296 ("net: phy: micrel: add toggling phy reset if PHY is not attac

Andrew Lunn informs me that there are alternative efforts
underway to fix this more properly.

Signed-off-by: David S. Miller <davem@davemloft.net>
---

Best regards,
Yoshihiro Shimoda

> This patch adds toggling phy reset if PHY is not attached. Otherwise,
> some boards (e.g. R-Car H3 Salvator-XS) cannot link up correctly if
> we do the following method:
>
> 1) Kernel boots by using initramfs.
> --> No open the nic, so phy_device_register() and phy_probe()
> deasserts the reset.
> 2) Kernel enters the suspend.
> --> So, keep the reset signal as deassert.
> --> On R-Car Salvator-XS board, unfortunately, the board power is
> turned off.
> 3) Kernel returns from suspend.
> 4) ifconfig eth0 up
> --> Then, since edge signal of the reset doesn't happen,
> it cannot link up.
> 5) ifconfig eth0 down
> 6) ifconfig eth0 up
> --> In this case, it can link up.
>
> Reported-by: Hiromitsu Yamasaki <hiromitsu.yamasaki.ym@renesas.com>
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> drivers/net/phy/micrel.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
> index 3db06b40580d..327f00034d01 100644
> --- a/drivers/net/phy/micrel.c
> +++ b/drivers/net/phy/micrel.c
> @@ -23,6 +23,7 @@
> * ksz9477
> */
>
> +#include <linux/delay.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/phy.h>
> @@ -725,6 +726,13 @@ static int kszphy_resume(struct phy_device *phydev)
> {
> int ret;
>
> + if (!phydev->attached_dev) {
> + /* If the PHY is not attached, toggle the reset */
> + phy_device_reset(phydev, 1);
> + udelay(1);
> + phy_device_reset(phydev, 0);
> + }
> +
> genphy_resume(phydev);
>
> ret = kszphy_config_reset(phydev);
> --
> 2.19.1