Re: [PATCH v6 1/2] platform/x86: dell-dw5826e: Add reset driver for DW5826e

[吳逼逼]

I've fixed it in v7.

Thank you.

Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> 於 2026年5月19日週二 下午6:20寫道：
>
> On Mon, 4 May 2026, Jack Wu wrote:
>
> > If the DW5826e is in a frozen state and unable to receive USB commands,
> > this driver provides a method for the user to reset the DW5826e via ACPI.
> >
> > E.g: echo 1 > /sys/bus/platform/devices/PALC0001\:00/wwan_reset
> >
> > Reviewed-by: Mario Limonciello (AMD) <superm1@xxxxxxxxxx>
> > Reviewed-by: Armin Wolf <W_Armin@xxxxxx>
> > Signed-off-by: Jack Wu <jackbb_wu@xxxxxxxxxx>
> > ---
> > v6:
> >   - Use same define for the DSM check
> > v5:
> >   - Use BIT() for the DSM method
> > v4:
> >   - Fix version of the ABI documentation to 7.2
> >   - Add include linux/types.h
> > v3:
> >   - Rename sysfs attribute from "pldr" to "wwan_reset" for clarity
> >   - Add ABI documentation for the wwan_reset sysfs interface
> >   - Validate _DSM method availability in probe using acpi_check_dsm()
> > v2:
> >   - Remove extra empty line
> >   - Add missing includes and Remove unnecessary includes, sort includes alphabetically
> >   - Remove noisy dev_info()
> >   - Handle obj->type != ACPI_TYPE_BUFFER as error with proper return code
> >   - Replace miscdevice/file_operations with sysfs attribute (DEVICE_ATTR_WO) to reduce boilerplate
> >   - Propagate trigger_palc_pldr() return code to userspace
> >   - Convert from acpi_driver to platform_driver
> > ---
> > ---
> >  .../testing/sysfs-driver-dell-dw5826e-reset   |  9 ++
> >  drivers/platform/x86/dell/Kconfig             |  6 ++
> >  drivers/platform/x86/dell/Makefile            |  2 +
> >  .../platform/x86/dell/dell-dw5826e-reset.c    | 93 +++++++++++++++++++
> >  4 files changed, 110 insertions(+)
> >  create mode 100644 Documentation/ABI/testing/sysfs-driver-dell-dw5826e-reset
> >  create mode 100644 drivers/platform/x86/dell/dell-dw5826e-reset.c
> >
> > diff --git a/Documentation/ABI/testing/sysfs-driver-dell-dw5826e-reset b/Documentation/ABI/testing/sysfs-driver-dell-dw5826e-reset
> > new file mode 100644
> > index 000000000000..a665e265633f
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-driver-dell-dw5826e-reset
> > @@ -0,0 +1,9 @@
> > +What:                /sys/bus/platform/devices/<PALC0001 device>/wwan_reset
> > +Date:                April 2026
>
> It's already May, and 7.2 won't be out even in May.
>
> > +KernelVersion:       7.2
> > +Contact:     Jackbb Wu <jackbb.wu@xxxxxxxxxx>
> > +Description:
> > +             Writing to this file triggers a Platform Level Device Reset
> > +             (PLDR) of the Dell DW5826e WWAN module via an ACPI _DSM
> > +             method. This can be used to recover the modem when it is in
> > +             a frozen state and unable to respond to USB commands.
> > diff --git a/drivers/platform/x86/dell/Kconfig b/drivers/platform/x86/dell/Kconfig
> > index 738c108c2163..c4540c837a88 100644
> > --- a/drivers/platform/x86/dell/Kconfig
> > +++ b/drivers/platform/x86/dell/Kconfig
> > @@ -276,4 +276,10 @@ config DELL_WMI_SYSMAN
> >         To compile this driver as a module, choose M here: the module will
> >         be called dell-wmi-sysman.
> >
> > +config DELL_DW5826E_RESET
> > +     tristate "Dell DW5826e PLDR reset support"
> > +     default m
> > +     depends on ACPI
> > +     help
> > +       This adds support for the Dell DW5826e PLDR reset via ACPI
> >  endif # X86_PLATFORM_DRIVERS_DELL
> > diff --git a/drivers/platform/x86/dell/Makefile b/drivers/platform/x86/dell/Makefile
> > index c7501c25e627..8150283cfd1d 100644
> > --- a/drivers/platform/x86/dell/Makefile
> > +++ b/drivers/platform/x86/dell/Makefile
> > @@ -28,3 +28,5 @@ obj-$(CONFIG_DELL_WMI_DESCRIPTOR)           += dell-wmi-descriptor.o
> >  obj-$(CONFIG_DELL_WMI_DDV)                   += dell-wmi-ddv.o
> >  obj-$(CONFIG_DELL_WMI_LED)                   += dell-wmi-led.o
> >  obj-$(CONFIG_DELL_WMI_SYSMAN)                        += dell-wmi-sysman/
> > +obj-$(CONFIG_DELL_DW5826E_RESET)             += dell-dw5826e-reset.o
> > +
> > diff --git a/drivers/platform/x86/dell/dell-dw5826e-reset.c b/drivers/platform/x86/dell/dell-dw5826e-reset.c
> > new file mode 100644
> > index 000000000000..d37c6a66c4c3
> > --- /dev/null
> > +++ b/drivers/platform/x86/dell/dell-dw5826e-reset.c
> > @@ -0,0 +1,93 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + *  dell-dw5826e-reset.c - Dell DW5826e reset driver
> > + *
> > + *  Copyright (C) 2026 Jackbb Wu <jackbb.wu@xxxxxxxxxx>
> > + */
> > +
> > +#include <linux/acpi.h>
> > +#include <linux/bits.h>
> > +#include <linux/device.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/types.h>
> > +#include <linux/uuid.h>
> > +
> > +#define PALC_DSM_FN_TRIGGER_PLDR    1
>
> Place BIT() into the define instead (I think I mentioned this already
> earlier), it's used by all sites so there's no good reason to keep in
> inline with the code (AFAICT):
>
> > +     obj = acpi_evaluate_dsm(handle, &palc_dsm_guid, 1, BIT(PALC_DSM_FN_TRIGGER_PLDR), NULL);
>
> > +     if (!acpi_check_dsm(handle, &palc_dsm_guid, 1, BIT(PALC_DSM_FN_TRIGGER_PLDR)))
>
>
> --
>  i.
>