Re: [PATCH v2] platform/x86: dell-dw5826e: Add reset driver for DW5826e

[吳逼逼]

Thanks for the feedback. I add the sysfs ABI documentation in
Documentation/ABI/testing/ and fix other issue. they include it in the
v3 version of the patch.

Armin Wolf <W_Armin@xxxxxx> 於 2026年4月13日週一 下午2:21寫道：
>
> Am 10.04.26 um 11:37 schrieb Jack Wu:
> > 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/pldr
> >
> > Signed-off-by: Jack Wu <jackbb_wu@xxxxxxxxxx>
> > ---
> > 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
> > ---
> > ---
> >   drivers/platform/x86/dell/Kconfig             |  6 ++
> >   drivers/platform/x86/dell/Makefile            |  2 +
> >   .../platform/x86/dell/dell-dw5826e-reset.c    | 83 +++++++++++++++++++
> >   3 files changed, 91 insertions(+)
> >   create mode 100644 drivers/platform/x86/dell/dell-dw5826e-reset.c
> >
> > 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..52002578ed68
> > --- /dev/null
> > +++ b/drivers/platform/x86/dell/dell-dw5826e-reset.c
> > @@ -0,0 +1,83 @@
> > +// 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/device.h>
> > +#include <linux/uuid.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +
> > +static guid_t palc_dsm_guid =
> > +     GUID_INIT(0x5a1a4bba, 0x8006, 0x487e, 0xbe, 0x0a, 0xac, 0xf5, 0xd8, 0xfd, 0xfe, 0x59);
> > +
> > +static int trigger_palc_pldr(struct device *dev, acpi_handle handle)
> > +{
> > +     union acpi_object *obj;
> > +     int ret = 0;
> > +
> > +     obj = acpi_evaluate_dsm(handle, &palc_dsm_guid, 1, 1, NULL);
> > +     if (!obj) {
> > +             dev_err(dev, "Failed to evaluate _DSM\n");
> > +             return -EIO;
> > +     }
> > +
> > +     if (obj->type != ACPI_TYPE_BUFFER) {
> > +             dev_err(dev, "Unexpected _DSM return type: %d\n", obj->type);
> > +             ret = -EINVAL;
> > +     }
> > +
> > +     ACPI_FREE(obj);
> > +     return ret;
> > +}
> > +
> > +static ssize_t pldr_store(struct device *dev, struct device_attribute *attr,
> > +                       const char *buf, size_t count)
> > +{
> > +     acpi_handle handle = ACPI_HANDLE(dev);
> > +     int ret;
> > +
> > +     ret = trigger_palc_pldr(dev, handle);
> > +     if (ret)
> > +             return ret;
> > +
> > +     return count;
> > +}
> > +static DEVICE_ATTR_WO(pldr);
> > +
> > +static struct attribute *palc_attrs[] = {
> > +     &dev_attr_pldr.attr,
> > +     NULL
> > +};
> > +ATTRIBUTE_GROUPS(palc);
> > +
> > +static int palc_probe(struct platform_device *pdev)
> > +{
> > +     if (!ACPI_HANDLE(&pdev->dev))
> > +             return -ENODEV;
> > +
>
> Hi, please check here if the _DSM method exists using acpi_check_dsm().
>
> Thanks,
> Armin Wolf
>
> > +     return 0;
> > +}
> > +
> > +static const struct acpi_device_id palc_acpi_ids[] = {
> > +     { "PALC0001", 0 },
> > +     { }
> > +};
> > +MODULE_DEVICE_TABLE(acpi, palc_acpi_ids);
> > +
> > +static struct platform_driver palc_driver = {
> > +     .driver = {
> > +             .name = "dell-dw5826e-reset",
> > +             .acpi_match_table = palc_acpi_ids,
> > +             .dev_groups = palc_groups,
> > +     },
> > +     .probe  = palc_probe,
> > +};
> > +module_platform_driver(palc_driver);
> > +
> > +MODULE_DESCRIPTION("Dell DW5826e reset driver");
> > +MODULE_LICENSE("GPL");
> > +MODULE_AUTHOR("JackBB Wu");
>