Re: [PATCH 2/2] phy: nuvoton: Add MA35D1 USB2 OTG PHY driver

[Joey Lu <a0987203069@gmail.com>]

On 6/11/2026 7:04 PM, Vinod Koul wrote:
> On 04-06-26, 18:12, Joey Lu wrote:
>> Add a PHY driver for the USB 2.0 PHYs in the Nuvoton MA35D1 SoC,
>> intended for use with the EHCI and OHCI host controllers.
>>
>> The MA35D1 SoC has two USB ports:
>>
>>    - USB0: an OTG port shared between a DWC2 gadget controller and
>>      EHCI0/OHCI0 host controllers.  A hardware mux automatically routes
>>      the physical USB0 signals to the appropriate controller based on the
>>      USB ID pin state.  The DWC2 IP is device-only in hardware,
>>      so host-mode operation on USB0 is handled entirely by EHCI0/OHCI0.
>>
>>    - USB1: a dedicated host-only port served by EHCI1/OHCI1.
>>
>> The driver implements:
>>    - Power-On Reset sequence with a guard that skips re-initialization if
>>      the PHY is already operational.  This protects PHY0 when the DWC2
>>      gadget driver has already run its own init before EHCI0 probes.
>>    - Optional resistor calibration trim via nuvoton,rcalcode.
>>    - Optional over-current detect polarity via nuvoton,oc-active-high.
>>    - For PHY0 only: a USB role switch that exposes the hardware ID pin
>>      state (PWRONOTP[16]).
>>
>> Signed-off-by: Joey Lu <a0987203069@gmail.com>
>> ---
>>   drivers/phy/nuvoton/Kconfig          |  15 ++
>>   drivers/phy/nuvoton/Makefile         |   1 +
>>   drivers/phy/nuvoton/phy-ma35d1-otg.c | 264 +++++++++++++++++++++++++++
>>   3 files changed, 280 insertions(+)
>>   create mode 100644 drivers/phy/nuvoton/phy-ma35d1-otg.c
>>
>> diff --git a/drivers/phy/nuvoton/Kconfig b/drivers/phy/nuvoton/Kconfig
>> index d02cae2db315..5fdd13f841e7 100644
>> --- a/drivers/phy/nuvoton/Kconfig
>> +++ b/drivers/phy/nuvoton/Kconfig
>> @@ -10,3 +10,18 @@ config PHY_MA35_USB
>>   	help
>>   	  Enable this to support the USB2.0 PHY on the Nuvoton MA35
>>   	  series SoCs.
>> +
>> +config PHY_MA35_USB_OTG
>> +	tristate "Nuvoton MA35 USB2.0 OTG PHY driver"
>> +	depends on ARCH_MA35 || COMPILE_TEST
>> +	depends on OF
>> +	select GENERIC_PHY
>> +	select MFD_SYSCON
>> +	select USB_ROLE_SWITCH
>> +	help
>> +	  Enable this to support the USB2.0 OTG PHY on the Nuvoton MA35
>> +	  series SoCs.  This driver handles PHY initialization for the
>> +	  EHCI/OHCI host controllers, including per-PHY power-on reset,
>> +	  resistor calibration trim, and over-current polarity
>> +	  configuration.  For the OTG port (PHY0), it also monitors the
>> +	  USB ID pin and registers a USB role switch.
>> diff --git a/drivers/phy/nuvoton/Makefile b/drivers/phy/nuvoton/Makefile
>> index 2937e3921898..3ecd76f35d7c 100644
>> --- a/drivers/phy/nuvoton/Makefile
>> +++ b/drivers/phy/nuvoton/Makefile
>> @@ -1,3 +1,4 @@
>>   # SPDX-License-Identifier: GPL-2.0
>>   
>>   obj-$(CONFIG_PHY_MA35_USB)		+= phy-ma35d1-usb2.o
>> +obj-$(CONFIG_PHY_MA35_USB_OTG)		+= phy-ma35d1-otg.o
> Have you considered reusing usb2 driver with a different power_on
> function? Or handle the differences internally in the driver. There are
> few similarities in two and some things are different
Thank you for the excellent suggestion regarding reusing the existing 
USB2 driver.

After further evaluation and local testing, I verified that it is 
entirely feasible to reuse the driver. Consequently, I will drop the 
separate phy-ma35d1-otg.c patch series and submit a new patch set that 
extends the existing phy-ma35d1-usb2.c mainline driver.

In the upcoming patch series, I will expand the driver's capability from 
a single-port PHY0 peripheral driver to a dual-port manager supporting 
both PHY0 and PHY1, while integrating OTG features.

BR,
Joey

>

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