mvebu: backport upstream patch to fix COMPHY reset

Upstream commit [1] included in the Linux kernel version 6.2 was
backported to Linux kernels 6.1.4, 6.0.18. It should be possible that it
is going to be backported even to the 5.15 series, but before it happens,
let's include it here.

It was discovered that on SOC Marvell Armada 3720, which is using e.g.
Turris MOX, and if you are also using it with older ARM Trusted Firmware
v1.5, it is not possible to detect connected USB 3.0 devices, but they
are working just fine when connected with USB 2.0 cable. This patch
fixes it.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/phy/marvell/phy-mvebu-a3700-comphy.c?id=b01d622d76134e9401970ffd3fbbb9a7051f976a

Reviewed-by: Robert Marko <robimarko@gmail.com>
Signed-off-by: Michal Hrusecky <michal.hrusecky@turris.com>
Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>
[improve commit description, added tag to the patch]

target/linux/mvebu/patches-5.15/710-v6.2-phy-marvell-phy-mvebu-a3700-comphy-Reset-COMPHY-regi.patch

@@ -0,0 +1,50 @@
+From b01d622d76134e9401970ffd3fbbb9a7051f976a Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
+Date: Tue, 20 Sep 2022 14:11:54 +0200
+Subject: [PATCH] phy: marvell: phy-mvebu-a3700-comphy: Reset COMPHY registers
+ before USB 3.0 power on
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Turris MOX board with older ARM Trusted Firmware version v1.5 is not able
+to detect any USB 3.0 device connected to USB-A port on Mox-A module after
+commit 0a6fc70d76bd ("phy: marvell: phy-mvebu-a3700-comphy: Remove broken
+reset support"). On the other hand USB 2.0 devices connected to the same
+USB-A port are working fine.
+
+It looks as if the older firmware configures COMPHY registers for USB 3.0
+somehow incompatibly for kernel driver. Experiments show that resetting
+COMPHY registers via setting SFT_RST auto-clearing bit in COMPHY_SFT_RESET
+register fixes this issue.
+
+Reset the COMPHY in mvebu_a3700_comphy_usb3_power_on() function as a first
+step after selecting COMPHY lane and USB 3.0 function. With this change
+Turris MOX board can successfully detect USB 3.0 devices again.
+
+Before the above mentioned commit this reset was implemented in PHY reset
+method, so this is the reason why there was no issue with older firmware
+version then.
+
+Fixes: 0a6fc70d76bd ("phy: marvell: phy-mvebu-a3700-comphy: Remove broken reset support")
+Reported-by: Marek Behún <kabel@kernel.org>
+Signed-off-by: Pali Rohár <pali@kernel.org>
+Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
+Link: https://lore.kernel.org/r/20220920121154.30115-1-pali@kernel.org
+Signed-off-by: Vinod Koul <vkoul@kernel.org>
+---
+ drivers/phy/marvell/phy-mvebu-a3700-comphy.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+--- a/drivers/phy/marvell/phy-mvebu-a3700-comphy.c
++++ b/drivers/phy/marvell/phy-mvebu-a3700-comphy.c
+@@ -826,6 +826,9 @@ mvebu_a3700_comphy_usb3_power_on(struct
+ 	if (ret)
+ 		return ret;
+ 
++	/* COMPHY register reset (cleared automatically) */
++	comphy_lane_reg_set(lane, COMPHY_SFT_RESET, SFT_RST, SFT_RST);
++
+ 	/*
+ 	 * 0. Set PHY OTG Control(0x5d034), bit 4, Power up OTG module The
+ 	 * register belong to UTMI module, so it is set in UTMI phy driver.