linux-kernel - Re: [PATCH v8 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver

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Message-ID: <2025112248-spoon-waffle-a508@gregkh>
Date: Sat, 22 Nov 2025 13:35:15 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Peter Griffin <peter.griffin@...aro.org>
Cc: Roy Luo <royluo@...gle.com>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	André Draszik <andre.draszik@...aro.org>,
	Tudor Ambarus <tudor.ambarus@...aro.org>,
	Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	Badhri Jagan Sridharan <badhri@...gle.com>,
	Doug Anderson <dianders@...gle.com>, linux-usb@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org,
	Joy Chakraborty <joychakr@...gle.com>,
	Naveen Kumar <mnkumar@...gle.com>
Subject: Re: [PATCH v8 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver

On Sat, Nov 22, 2025 at 11:58:39AM +0000, Peter Griffin wrote:
> Hi Roy,
> 
> Thanks for your patch. It's great to see Laguna support being added upstream.
> 
> On Sat, 22 Nov 2025 at 09:32, Roy Luo <royluo@...gle.com> wrote:
> >
> > Add support for the DWC3 USB controller found on Google Tensor G5
> > (codename: laguna). The controller features dual-role functionality
> > and hibernation.
> >
> > The primary focus is implementing hibernation support in host mode,
> > enabling the controller to enter a low-power state (D3). This is
> > particularly relevant during system power state transition and
> > runtime power management for power efficiency.
> > Highlights:
> > - Align suspend callback with dwc3_suspend_common() for deciding
> >   between a full teardown and hibernation in host mode.
> > - Integration with `psw` (power switchable) and `top` power domains,
> >   managing their states and device links to support hibernation.
> > - A notifier callback dwc3_google_usb_psw_pd_notifier() for
> >   `psw` power domain events to manage controller state
> >   transitions to/from D3.
> > - Coordination of the `non_sticky` reset during power state
> >   transitions, asserting it on D3 entry and deasserting on D0 entry
> >   in hibernation scenario.
> > - Handling of high-speed and super-speed PME interrupts
> >   that are generated by remote wakeup during hibernation.
> >
> > Co-developed-by: Joy Chakraborty <joychakr@...gle.com>
> > Signed-off-by: Joy Chakraborty <joychakr@...gle.com>
> > Co-developed-by: Naveen Kumar <mnkumar@...gle.com>
> > Signed-off-by: Naveen Kumar <mnkumar@...gle.com>
> > Signed-off-by: Roy Luo <royluo@...gle.com>
> > ---
> >  drivers/usb/dwc3/Kconfig       |  13 +
> >  drivers/usb/dwc3/Makefile      |   1 +
> >  drivers/usb/dwc3/dwc3-google.c | 628 +++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 642 insertions(+)
> >
> > diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
> > index 4925d15084f816d3ff92059b476ebcc799b56b51..f58c70dabf108878cbefe0abea88572d9ae81e26 100644
> > --- a/drivers/usb/dwc3/Kconfig
> > +++ b/drivers/usb/dwc3/Kconfig
> > @@ -200,4 +200,17 @@ config USB_DWC3_GENERIC_PLAT
> >           the dwc3 child node in the device tree.
> >           Say 'Y' or 'M' here if your platform integrates DWC3 in a similar way.
> >
> > +config USB_DWC3_GOOGLE
> > +       tristate "Google Platform"
> > +       depends on COMPILE_TEST
> > +       depends on OF && COMMON_CLK && RESET_CONTROLLER
> > +       help
> > +         Support the DesignWare Core USB3 IP found on Google Tensor
> > +         SoCs, starting with the G5 generation. This driver includes
> 
> consider adding: (Laguna)

What is "laguna" and why should it be listed here?

> > +         support for hibernation in host mode.
> > +         Say 'Y' or 'M' if you have one such device.
> > +
> > +         To compile this driver as a module, choose M here: the
> > +         module will be called dwc3-google.ko.
> > +
> >  endif
> > diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
> > index 96469e48ff9d189cc8d0b65e65424eae2158bcfe..cf1cd408d938b3ac26d58b9be7fcc5af3ee82660 100644
> > --- a/drivers/usb/dwc3/Makefile
> > +++ b/drivers/usb/dwc3/Makefile
> > @@ -58,3 +58,4 @@ obj-$(CONFIG_USB_DWC3_XILINX)         += dwc3-xilinx.o
> >  obj-$(CONFIG_USB_DWC3_OCTEON)          += dwc3-octeon.o
> >  obj-$(CONFIG_USB_DWC3_RTK)             += dwc3-rtk.o
> >  obj-$(CONFIG_USB_DWC3_GENERIC_PLAT)    += dwc3-generic-plat.o
> > +obj-$(CONFIG_USB_DWC3_GOOGLE)          += dwc3-google.o
> > diff --git a/drivers/usb/dwc3/dwc3-google.c b/drivers/usb/dwc3/dwc3-google.c
> > new file mode 100644
> > index 0000000000000000000000000000000000000000..53e04a5409d8a11eb025b0f5cd351cb1b33281ab
> > --- /dev/null
> > +++ b/drivers/usb/dwc3/dwc3-google.c
> > @@ -0,0 +1,628 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * dwc3-google.c - Google DWC3 Specific Glue Layer
> > + *
> > + * Copyright (c) 2025, Google LLC
> > + * Author: Roy Luo <royluo@...gle.com>
> > + */
> > +
> > +#include <linux/of.h>
> > +#include <linux/bitfield.h>
> > +#include <linux/irq.h>
> > +#include <linux/clk.h>
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/reset.h>
> > +#include <linux/pm_domain.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/regmap.h>
> > +#include <linux/mfd/syscon.h>
> 
> Please sort the headers alphabetically. It helps avoid duplicates and
> is easier when adding new headers.

There is no such requirement for USB drivers.

thanks,

greg k-h