From: Pali Rohár pali@kernel.org
[ Upstream commit b01d622d76134e9401970ffd3fbbb9a7051f976a ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/phy/marvell/phy-mvebu-a3700-comphy.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/phy/marvell/phy-mvebu-a3700-comphy.c b/drivers/phy/marvell/phy-mvebu-a3700-comphy.c index 67712c77d806..d641b345afa3 100644 --- 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 mvebu_a3700_comphy_lane *lane) 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.