[v2,2/2] platform/x86: dell: Add new dell-wmi-ddv driver

diff --git a/Documentation/ABI/testing/debugfs-dell-wmi-ddv b/Documentation/ABI/testing/debugfs-dell-wmi-ddv
new file mode 100644
index 000000000000..fbcc5d6f7388
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-dell-wmi-ddv
@@ -0,0 +1,21 @@ 
+What:		/sys/kernel/debug/dell-wmi-ddv-<wmi_device_name>/fan_sensor_information
+Date:		September 2022
+KernelVersion:	6.1
+Contact:	Armin Wolf <W_Armin@gmx.de>
+Description:
+		This file contains the contents of the fan sensor information buffer,
+		which contains fan sensor entries and a terminating character (0xFF).
+
+		Each fan sensor entry consists of three bytes with an unknown meaning,
+		interested people may use this file for reverse-engineering.
+
+What:		/sys/kernel/debug/dell-wmi-ddv-<wmi_device_name>/thermal_sensor_information
+Date:		September 2022
+KernelVersion:	6.1
+Contact:	Armin Wolf <W_Armin@gmx.de>
+Description:
+		This file contains the contents of the thermal sensor information buffer,
+		which contains thermal sensor entries and a terminating character (0xFF).
+
+		Each thermal sensor entry consists of five bytes with an unknown meaning,
+		interested people may use this file for reverse-engineering.
diff --git a/Documentation/ABI/testing/sysfs-platform-dell-wmi-ddv b/Documentation/ABI/testing/sysfs-platform-dell-wmi-ddv
new file mode 100644
index 000000000000..1d97ad615c66
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-platform-dell-wmi-ddv
@@ -0,0 +1,7 @@ 
+What:		/sys/class/power_supply/<battery_name>/eppid
+Date:		September 2022
+KernelVersion:	6.1
+Contact:	Armin Wolf <W_Armin@gmx.de>
+Description:
+		Reports the Dell ePPID (electronic Dell Piece Part Identification)
+		of the ACPI battery.
diff --git a/MAINTAINERS b/MAINTAINERS
index 6bb894ea4a77..d9fd4c9eebbc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5821,6 +5821,13 @@  L:	Dell.Client.Kernel@dell.com
 S:	Maintained
 F:	drivers/platform/x86/dell/dell-wmi-descriptor.c

+DELL WMI DDV DRIVER
+M:	Armin Wolf <W_Armin@gmx.de>
+S:	Maintained
+F:	Documentation/ABI/testing/debugfs-dell-wmi-ddv
+F:	Documentation/ABI/testing/sysfs-platform-dell-wmi-ddv
+F:	drivers/platform/x86/dell/dell-wmi-ddv.c
+
 DELL WMI SYSMAN DRIVER
 M:	Divya Bharathi <divya.bharathi@dell.com>
 M:	Prasanth Ksr <prasanth.ksr@dell.com>
diff --git a/drivers/platform/x86/dell/Kconfig b/drivers/platform/x86/dell/Kconfig
index 25421e061c47..d319de8f2132 100644
--- a/drivers/platform/x86/dell/Kconfig
+++ b/drivers/platform/x86/dell/Kconfig
@@ -189,6 +189,19 @@  config DELL_WMI_DESCRIPTOR
 	default n
 	depends on ACPI_WMI

+config DELL_WMI_DDV
+	tristate "Dell WMI sensors Support"
+	default m
+	depends on ACPI_BATTERY
+	depends on ACPI_WMI
+	help
+	  This option adds support for WMI-based sensors like
+	  battery temperature sensors found on some Dell notebooks.
+	  It also supports reading of the battery ePPID.
+
+	  To compile this drivers as a module, choose M here: the module will
+	  be called dell-wmi-ddv.
+
 config DELL_WMI_LED
 	tristate "External LED on Dell Business Netbooks"
 	default m
diff --git a/drivers/platform/x86/dell/Makefile b/drivers/platform/x86/dell/Makefile
index ddba1df71e80..1b8942426622 100644
--- a/drivers/platform/x86/dell/Makefile
+++ b/drivers/platform/x86/dell/Makefile
@@ -19,5 +19,6 @@  dell-wmi-objs				:= dell-wmi-base.o
 dell-wmi-$(CONFIG_DELL_WMI_PRIVACY)	+= dell-wmi-privacy.o
 obj-$(CONFIG_DELL_WMI_AIO)		+= dell-wmi-aio.o
 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/
diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
new file mode 100644
index 000000000000..6ccce90f475d
--- /dev/null
+++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
@@ -0,0 +1,361 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * dell-wmi-ddv.c -- Linux driver for WMI sensor information on Dell notebooks.
+ *
+ * Copyright (C) 2022 Armin Wolf <W_Armin@gmx.de>
+ */
+
+#define pr_format(fmt) KBUILD_MODNAME ": " fmt
+
+#include <acpi/battery.h>
+#include <linux/acpi.h>
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/kstrtox.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/limits.h>
+#include <linux/power_supply.h>
+#include <linux/seq_file.h>
+#include <linux/sysfs.h>
+#include <linux/wmi.h>
+
+#define DRIVER_NAME	"dell-wmi-ddv"
+
+#define DELL_DDV_SUPPORTED_INTERFACE 2
+#define DELL_DDV_GUID	"8A42EA14-4F2A-FD45-6422-0087F7A7E608"
+
+enum dell_ddv_method {
+	DELL_DDV_BATTERY_DESIGN_CAPACITY	= 0x01,
+	DELL_DDV_BATTERY_FULL_CHARGE_CAPACITY	= 0x02,
+	DELL_DDV_BATTERY_MANUFACTURE_NAME	= 0x03,
+	DELL_DDV_BATTERY_MANUFACTURE_DATE	= 0x04,
+	DELL_DDV_BATTERY_SERIAL_NUMBER		= 0x05,
+	DELL_DDV_BATTERY_CHEMISTRY_VALUE	= 0x06,
+	DELL_DDV_BATTERY_TEMPERATURE		= 0x07,
+	DELL_DDV_BATTERY_CURRENT		= 0x08,
+	DELL_DDV_BATTERY_VOLTAGE		= 0x09,
+	DELL_DDV_BATTERY_MANUFACTURER_ACCESS	= 0x0A,
+	DELL_DDV_BATTERY_RELATIVE_CHARGE_STATE	= 0x0B,
+	DELL_DDV_BATTERY_CYCLE_COUNT		= 0x0C,
+	DELL_DDV_BATTERY_EPPID			= 0x0D,
+	DELL_DDV_BATTERY_RAW_ANALYTICS_START	= 0x0E,
+	DELL_DDV_BATTERY_RAW_ANALYTICS		= 0x0F,
+	DELL_DDV_BATTERY_DESIGN_VOLTAGE		= 0x10,
+
+	DELL_DDV_INTERFACE_VERSION		= 0x12,
+
+	DELL_DDV_FAN_SENSOR_INFORMATION		= 0x20,
+	DELL_DDV_THERMAL_SENSOR_INFORMATION	= 0x22,
+};
+
+struct dell_wmi_ddv_data {
+	struct acpi_battery_hook hook;
+	struct device_attribute temp_attr, eppid_attr;
+	struct wmi_device *wdev;
+};
+
+static int dell_wmi_ddv_query_type(struct wmi_device *wdev, enum dell_ddv_method method, u32 arg,
+				   union acpi_object **result, acpi_object_type type)
+{
+	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
+	const struct acpi_buffer in = {
+		.length = sizeof(arg),
+		.pointer = &arg,
+	};
+	union acpi_object *obj;
+	acpi_status ret;
+
+	ret = wmidev_evaluate_method(wdev, 0x0, method, &in, &out);
+	if (ACPI_FAILURE(ret))
+		return -EIO;
+
+	obj = out.pointer;
+	if (!obj)
+		return -ENODATA;
+
+	if (obj->type != type) {
+		kfree(obj);
+		return -EIO;
+	}
+
+	*result = obj;
+
+	return 0;
+}
+
+static int dell_wmi_ddv_query_integer(struct wmi_device *wdev, enum dell_ddv_method method,
+				      u32 arg, u32 *res)
+{
+	union acpi_object *obj;
+	int ret;
+
+	ret = dell_wmi_ddv_query_type(wdev, method, arg, &obj, ACPI_TYPE_INTEGER);
+	if (ret < 0)
+		return ret;
+
+	if (obj->integer.value <= U32_MAX)
+		*res = (u32)obj->integer.value;
+	else
+		ret = -ERANGE;
+
+	kfree(obj);
+
+	return ret;
+}
+
+static int dell_wmi_ddv_query_buffer(struct wmi_device *wdev, enum dell_ddv_method method,
+				     u32 arg, union acpi_object **result)
+{
+	union acpi_object *obj;
+	u64 buffer_size;
+	int ret;
+
+	ret = dell_wmi_ddv_query_type(wdev, method, arg, &obj, ACPI_TYPE_PACKAGE);
+	if (ret < 0)
+		return ret;
+
+	if (obj->package.count != 2)
+		goto err_free;
+
+	if (obj->package.elements[0].type != ACPI_TYPE_INTEGER)
+		goto err_free;
+
+	buffer_size = obj->package.elements[0].integer.value;
+
+	if (obj->package.elements[1].type != ACPI_TYPE_BUFFER)
+		goto err_free;
+
+	if (buffer_size != obj->package.elements[1].buffer.length) {
+		dev_warn(&wdev->dev,
+			 FW_WARN "ACPI buffer size (%llu) does not match WMI buffer size (%d)\n",
+			 buffer_size, obj->package.elements[1].buffer.length);
+
+		goto err_free;
+	}
+
+	*result = obj;
+
+	return 0;
+
+err_free:
+	kfree(obj);
+
+	return -EIO;
+}
+
+static int dell_wmi_ddv_query_string(struct wmi_device *wdev, enum dell_ddv_method method,
+				     u32 arg, union acpi_object **result)
+{
+	return dell_wmi_ddv_query_type(wdev, method, arg, result, ACPI_TYPE_STRING);
+}
+
+static int dell_wmi_ddv_battery_index(struct acpi_device *acpi_dev, u32 *index)
+{
+	const char *uid_str = acpi_device_uid(acpi_dev);
+
+	if (!uid_str)
+		return -ENODEV;
+
+	return kstrtou32(uid_str, 10, index);
+}
+
+static ssize_t temp_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dell_wmi_ddv_data *data = container_of(attr, struct dell_wmi_ddv_data, temp_attr);
+	u32 index, value;
+	int ret;
+
+	ret = dell_wmi_ddv_battery_index(to_acpi_device(dev->parent), &index);
+	if (ret < 0)
+		return ret;
+
+	ret = dell_wmi_ddv_query_integer(data->wdev, DELL_DDV_BATTERY_TEMPERATURE, index, &value);
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", DIV_ROUND_CLOSEST(value, 10));
+}
+
+static ssize_t eppid_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dell_wmi_ddv_data *data = container_of(attr, struct dell_wmi_ddv_data, eppid_attr);
+	union acpi_object *obj;
+	u32 index;
+	int ret;
+
+	ret = dell_wmi_ddv_battery_index(to_acpi_device(dev->parent), &index);
+	if (ret < 0)
+		return ret;
+
+	ret = dell_wmi_ddv_query_string(data->wdev, DELL_DDV_BATTERY_EPPID, index, &obj);
+	if (ret < 0)
+		return ret;
+
+	ret = sysfs_emit(buf, "%s\n", obj->string.pointer);
+
+	kfree(obj);
+
+	return ret;
+}
+
+static int dell_wmi_ddv_add_battery(struct power_supply *battery, struct acpi_battery_hook *hook)
+{
+	struct dell_wmi_ddv_data *data = container_of(hook, struct dell_wmi_ddv_data, hook);
+	u32 index;
+	int ret;
+
+	/* Return 0 instead of error to avoid being unloaded */
+	ret = dell_wmi_ddv_battery_index(to_acpi_device(battery->dev.parent), &index);
+	if (ret < 0)
+		return 0;
+
+	ret = device_create_file(&battery->dev, &data->temp_attr);
+	if (ret < 0)
+		return ret;
+
+	ret = device_create_file(&battery->dev, &data->eppid_attr);
+	if (ret < 0) {
+		device_remove_file(&battery->dev, &data->temp_attr);
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static int dell_wmi_ddv_remove_battery(struct power_supply *battery, struct acpi_battery_hook *hook)
+{
+	struct dell_wmi_ddv_data *data = container_of(hook, struct dell_wmi_ddv_data, hook);
+
+	device_remove_file(&battery->dev, &data->temp_attr);
+	device_remove_file(&battery->dev, &data->eppid_attr);
+
+	return 0;
+}
+
+static void dell_wmi_ddv_battery_remove(void *data)
+{
+	struct acpi_battery_hook *hook = data;
+
+	battery_hook_unregister(hook);
+}
+
+static int dell_wmi_ddv_battery_add(struct dell_wmi_ddv_data *data)
+{
+	data->hook.name = "Dell DDV Battery Extension";
+	data->hook.add_battery = dell_wmi_ddv_add_battery;
+	data->hook.remove_battery = dell_wmi_ddv_remove_battery;
+
+	sysfs_attr_init(&data->temp_attr.attr);
+	data->temp_attr.attr.name = "temp";
+	data->temp_attr.attr.mode = 0444;
+	data->temp_attr.show = temp_show;
+
+	sysfs_attr_init(&data->eppid_attr.attr);
+	data->eppid_attr.attr.name = "eppid";
+	data->eppid_attr.attr.mode = 0444;
+	data->eppid_attr.show = eppid_show;
+
+	battery_hook_register(&data->hook);
+
+	return devm_add_action_or_reset(&data->wdev->dev, dell_wmi_ddv_battery_remove, &data->hook);
+}
+
+static int dell_wmi_ddv_buffer_read(struct seq_file *seq, enum dell_ddv_method method)
+{
+	struct device *dev = seq->private;
+	struct dell_wmi_ddv_data *data = dev_get_drvdata(dev);
+	union acpi_object *obj;
+	union acpi_object buf;
+	int ret;
+
+	ret = dell_wmi_ddv_query_buffer(data->wdev, method, 0, &obj);
+	if (ret < 0)
+		return ret;
+
+	buf = obj->package.elements[1];
+	ret = seq_write(seq, buf.buffer.pointer, buf.buffer.length);
+	kfree(obj);
+
+	return ret;
+}
+
+static int dell_wmi_ddv_fan_read(struct seq_file *seq, void *offset)
+{
+	return dell_wmi_ddv_buffer_read(seq, DELL_DDV_FAN_SENSOR_INFORMATION);
+}
+
+static int dell_wmi_ddv_temp_read(struct seq_file *seq, void *offset)
+{
+	return dell_wmi_ddv_buffer_read(seq, DELL_DDV_THERMAL_SENSOR_INFORMATION);
+}
+
+static void dell_wmi_ddv_debugfs_remove(void *data)
+{
+	struct dentry *entry = data;
+
+	debugfs_remove(entry);
+}
+
+static void dell_wmi_ddv_debugfs_init(struct wmi_device *wdev)
+{
+	struct dentry *entry;
+	char name[64];
+
+	scnprintf(name, ARRAY_SIZE(name), "%s-%s", DRIVER_NAME, dev_name(&wdev->dev));
+	entry = debugfs_create_dir(name, NULL);
+
+	debugfs_create_devm_seqfile(&wdev->dev, "fan_sensor_information", entry,
+				    dell_wmi_ddv_fan_read);
+	debugfs_create_devm_seqfile(&wdev->dev, "thermal_sensor_information", entry,
+				    dell_wmi_ddv_temp_read);
+
+	devm_add_action_or_reset(&wdev->dev, dell_wmi_ddv_debugfs_remove, entry);
+}
+
+static int dell_wmi_ddv_probe(struct wmi_device *wdev, const void *context)
+{
+	struct dell_wmi_ddv_data *data;
+	u32 version;
+	int ret;
+
+	ret = dell_wmi_ddv_query_integer(wdev, DELL_DDV_INTERFACE_VERSION, 0, &version);
+	if (ret < 0)
+		return ret;
+
+	dev_dbg(&wdev->dev, "WMI interface version: %d\n", version);
+	if (version != DELL_DDV_SUPPORTED_INTERFACE)
+		return -ENODEV;
+
+	data = devm_kzalloc(&wdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	dev_set_drvdata(&wdev->dev, data);
+	data->wdev = wdev;
+
+	dell_wmi_ddv_debugfs_init(wdev);
+
+	return dell_wmi_ddv_battery_add(data);
+}
+
+static const struct wmi_device_id dell_wmi_ddv_id_table[] = {
+	{ DELL_DDV_GUID, NULL },
+	{ }
+};
+MODULE_DEVICE_TABLE(wmi, dell_wmi_ddv_id_table);
+
+static struct wmi_driver dell_wmi_ddv_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+	},
+	.id_table = dell_wmi_ddv_id_table,
+	.probe = dell_wmi_ddv_probe,
+};
+module_wmi_driver(dell_wmi_ddv_driver);
+
+MODULE_AUTHOR("Armin Wolf <W_Armin@gmx.de>");
+MODULE_DESCRIPTION("Dell WMI sensor driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index aff23309b5d3..f307d8c5c6c3 100644
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -108,6 +108,7 @@  MODULE_DEVICE_TABLE(acpi, wmi_device_ids);
 /* allow duplicate GUIDs as these device drivers use struct wmi_driver */
 static const char * const allow_duplicates[] = {
 	"05901221-D566-11D1-B2F0-00A0C9062910",	/* wmi-bmof */
+	"8A42EA14-4F2A-FD45-6422-0087F7A7E608",	/* dell-wmi-ddv */
 	NULL
 };