Re: [PATCH v4 4/6 RESEND] platform/x86: Add Lenovo Capability Data 01 WMI Driver

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Am 02.04.25 um 23:22 schrieb Derek John Clark:

On Thu, Mar 27, 2025 at 5:56 AM Ilpo Järvinen
<ilpo.jarvinen@xxxxxxxxxxxxxxx> wrote:
On Mon, 17 Mar 2025, Derek J. Clark wrote:

Adds lenovo-wmi-capdata01 driver which provides the
LENOVO_CAPABILITY_DATA_01 WMI data block that comes on "Other Mode"
enabled hardware. Provides an interface for querying if a given
attribute is supported by the hardware, as well as its default_value,
max_value, min_value, and step increment.

Signed-off-by: Derek J. Clark <derekjohn.clark@xxxxxxxxx>
---
v4:
  - Make driver data a private struct, remove references from Other Mode
    driver.
  - Don't cache data at device initialization. Instead, on component bind,
    cache the data on a member variable of the Other Mode driver data
    passed as a void pointer.
  - Add header file for capdata01 structs.
  - Add new struct to pass capdata01 array data and array length to Other
    Mode.
v3:
- Add as component to lenovo-wmi-other driver.
v2:
- Use devm_kmalloc to ensure driver can be instanced, remove global
   reference.
- Ensure reverse Christmas tree for all variable declarations.
- Remove extra whitespace.
- Use guard(mutex) in all mutex instances, global mutex.
- Use pr_fmt instead of adding the driver name to each pr_err.
- Remove noisy pr_info usage.
- Rename capdata_wmi to lenovo_wmi_cd01_priv and cd01_wmi to priv.
- Use list to get the lenovo_wmi_cd01_priv instance in
   lenovo_wmi_capdata01_get as none of the data provided by the macros
   that will use it can pass a member of the struct for use in
   container_of.
---
  MAINTAINERS                                 |   2 +
  drivers/platform/x86/Kconfig                |   4 +
  drivers/platform/x86/Makefile               |   1 +
  drivers/platform/x86/lenovo-wmi-capdata01.c | 136 ++++++++++++++++++++
  drivers/platform/x86/lenovo-wmi-capdata01.h |  29 +++++
  5 files changed, 172 insertions(+)
  create mode 100644 drivers/platform/x86/lenovo-wmi-capdata01.c
  create mode 100644 drivers/platform/x86/lenovo-wmi-capdata01.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 6dde75922aaf..56ead241a053 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13164,6 +13164,8 @@ L:    platform-driver-x86@xxxxxxxxxxxxxxx
  S:   Maintained
  F:   Documentation/wmi/devices/lenovo-wmi-gamezone.rst
  F:   Documentation/wmi/devices/lenovo-wmi-other.rst
+F:   drivers/platform/x86/lenovo-wmi-capdata01.c
+F:   drivers/platform/x86/lenovo-wmi-capdata01.h
  F:   drivers/platform/x86/lenovo-wmi-events.c
  F:   drivers/platform/x86/lenovo-wmi-events.h
  F:   drivers/platform/x86/lenovo-wmi-helpers.c
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 13b8f4ac5dc5..64663667f0cb 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -467,6 +467,10 @@ config LENOVO_WMI_HELPERS
       tristate
       depends on ACPI_WMI

+config LENOVO_WMI_DATA01
+     tristate
+     depends on ACPI_WMI
+
  config IDEAPAD_LAPTOP
       tristate "Lenovo IdeaPad Laptop Extras"
       depends on ACPI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index fc039839286a..7a35c77221b7 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_THINKPAD_LMI)  += think-lmi.o
  obj-$(CONFIG_YOGABOOK)               += lenovo-yogabook.o
  obj-$(CONFIG_YT2_1380)               += lenovo-yoga-tab2-pro-1380-fastcharger.o
  obj-$(CONFIG_LENOVO_WMI_CAMERA)      += lenovo-wmi-camera.o
+obj-$(CONFIG_LENOVO_WMI_DATA01)      += lenovo-wmi-capdata01.o
  obj-$(CONFIG_LENOVO_WMI_EVENTS)      += lenovo-wmi-events.o
  obj-$(CONFIG_LENOVO_WMI_HELPERS)     += lenovo-wmi-helpers.o

diff --git a/drivers/platform/x86/lenovo-wmi-capdata01.c b/drivers/platform/x86/lenovo-wmi-capdata01.c
new file mode 100644
index 000000000000..b6876611ffd9
--- /dev/null
+++ b/drivers/platform/x86/lenovo-wmi-capdata01.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * LENOVO_CAPABILITY_DATA_01 WMI data block driver.
Add a empty comment line here, you might want to rephrase the opening of
the paragraph after splitting these apart.

This interface provides
+ * information on tunable attributes used by the "Other Mode" WMI interface,
+ * including if it is supported by the hardware, the default_value, max_value,
+ * min_value, and step increment.
+ *
+ * Copyright(C) 2025 Derek J. Clark <derekjohn.clark@xxxxxxxxx>
+ */
+
+#include <linux/cleanup.h>
+#include <linux/component.h>
+#include <linux/container_of.h>
+#include <linux/device.h>
+#include <linux/gfp_types.h>
+#include <linux/types.h>
+#include <linux/wmi.h>
Add an empty line here please.

+#include "lenovo-wmi-capdata01.h"
+
+/* Interface GUIDs */
+#define LENOVO_CAPABILITY_DATA_01_GUID "7A8F5407-CB67-4D6E-B547-39B3BE018154"
+
+struct lwmi_cd01_priv {
+     struct wmi_device *wdev;
+};
+
+/*
+ * lenovo_cd01_component_bind() - On master bind, caches all capability data on
+ * the master device.
Is this "On master bind" something that the caller should be doing? IMO,
that would belong to description paragraph instead of the function
summary.

Acked

+ * @cd01_dev: Pointer to the capability data 01 parent device.
+ * @om_dev: Pointer to the other mode parent device.
+ * @data: capdata01_list object pointer to return the capability data with.
+ *
+ * Returns: 0, or an error.
Return:

+ */
+static int lenovo_cd01_component_bind(struct device *cd01_dev,
+                                   struct device *om_dev, void *data)
+{
+     struct lwmi_cd01_priv *priv = dev_get_drvdata(cd01_dev);
+     int count, idx;
+
+     if (!priv)
+             return -ENODEV;
+
+     count = wmidev_instance_count(priv->wdev);
+
+     if (count == 0)
+             return -EINVAL;
+
+     ((struct cd01_list *)data)->count = count;
Please create a local variable with the correct type and since data is
void *, you don't need to cast it while assigning to that local variable.

This will be reworked a bit with Armin's suggestions.

+     ((struct cd01_list *)data)->data = devm_kmalloc_array(om_dev, count,
+                                                           sizeof(struct capdata01 *),
sizeof() should preferrably take the type directly from ->data (with the
correct amount of * chars).

With Armin's suggestion I'll be using struct_size, but I'll note this
for future reference, thanks.

+                                                           GFP_KERNEL);
+     if (!data)
+             return -ENOMEM;
+
+     for (idx = 0; idx < count; idx++) {
+             union acpi_object *ret_obj __free(kfree) = NULL;
+
+             ret_obj = wmidev_block_query(priv->wdev, idx);
+             if (!ret_obj) {
+                     ((struct cd01_list *)data)->data[idx] = NULL;
+                     continue;
+             }
+             if (ret_obj->type != ACPI_TYPE_BUFFER) {
+                     ((struct cd01_list *)data)->data[idx] = NULL;
+                     continue;
+             }
+
+             if (ret_obj->buffer.length != sizeof(struct capdata01)) {
You could consider joining these 3 if()s with || to avoid having to
repeat the NULL assignment and continue.

devm_kzalloc will take care of the NULL assignment going forward. for
!ret_obj, should I return an error here instead? It seems like a
problem if that fails.

Returning an error if a ACPI object is invalid should be OK here. This way the driver
ensures that it either exports all capdata entries on a given machine or none at all.

Just a side note: the check "ret_obj->buffer.length != sizeof(struct capdata01)" should
be turned into "ret_obj->buffer.length < sizeof(struct capdata01)" to also accept oversized
buffers. This would mimic the behavior of the Windows WMI-ACPI driver.

Thanks,
Armin Wolf

+                     ((struct cd01_list *)data)->data[idx] = NULL;
+                     continue;
+             }
+
+             ((struct cd01_list *)data)->data[idx] =
+                     devm_kmemdup(om_dev, ret_obj->buffer.pointer,
+                                  ret_obj->buffer.length, GFP_KERNEL);
+     }
+     return 0;
+}
+
+static const struct component_ops lenovo_cd01_component_ops = {
+     .bind = lenovo_cd01_component_bind,
+};
+
+static int lwmi_cd01_probe(struct wmi_device *wdev, const void *context)
+
+{
+     struct lwmi_cd01_priv *priv;
+     int ret;
+
+     priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
+     if (!priv)
+             return -ENOMEM;
+
+     priv->wdev = wdev;
+     dev_set_drvdata(&wdev->dev, priv);
+
+     ret = component_add(&wdev->dev, &lenovo_cd01_component_ops);
+
+     return ret;
+}
+
+static void lwmi_cd01_remove(struct wmi_device *wdev)
+{
+     component_del(&wdev->dev, &lenovo_cd01_component_ops);
+}
+
+static const struct wmi_device_id lwmi_cd01_id_table[] = {
+     { LENOVO_CAPABILITY_DATA_01_GUID, NULL },
+     {}
+};
+
+static struct wmi_driver lwmi_cd01_driver = {
+     .driver = {
+             .name = "lenovo_wmi_cd01",
+             .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+     },
+     .id_table = lwmi_cd01_id_table,
+     .probe = lwmi_cd01_probe,
+     .remove = lwmi_cd01_remove,
+     .no_singleton = true,
+};
+
+int lwmi_cd01_match(struct device *dev, void *data)
+{
+     return dev->driver == &lwmi_cd01_driver.driver;
+}
+EXPORT_SYMBOL_NS_GPL(lwmi_cd01_match, "LENOVO_WMI_CD01");
+
+module_wmi_driver(lwmi_cd01_driver);
+
+MODULE_DEVICE_TABLE(wmi, lwmi_cd01_id_table);
+MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@xxxxxxxxx>");
+MODULE_DESCRIPTION("Lenovo Capability Data 01 WMI Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/platform/x86/lenovo-wmi-capdata01.h b/drivers/platform/x86/lenovo-wmi-capdata01.h
new file mode 100644
index 000000000000..c7067a8d0398
--- /dev/null
+++ b/drivers/platform/x86/lenovo-wmi-capdata01.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * Copyright(C) 2025 Derek J. Clark <derekjohn.clark@xxxxxxxxx>
+ *
Extra line

+ */
+
+#ifndef _LENOVO_WMI_CAPDATA01_H_
+#define _LENOVO_WMI_CAPDATA01_H_
+
+#include <linux/device.h>
Please fwd declare struct device instead.

+#include <linux/types.h>
+
+struct capdata01 {
+     u32 id;
+     u32 supported;
+     u32 default_value;
+     u32 step;
+     u32 min_value;
+     u32 max_value;
+};
+
+struct cd01_list {
+     struct capdata01 **data;
+     int count;
+};
+
+int lwmi_cd01_match(struct device *dev, void *data);
+
+#endif /* !_LENOVO_WMI_CAPDATA01_H_ */

--
  i.






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