Message-Id: <20211115210842.11972-2-pauk.denis@gmail.com>
Date:   Mon, 15 Nov 2021 23:08:40 +0200
From:   Denis Pauk <pauk.denis@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     eugene.shalygin@...il.com, andy.shevchenko@...il.com,
        pauk.denis@...il.com, platform-driver-x86@...r.kernel.org,
        thomas@...ssschuh.net, kernel@...davale.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Tor Vic <torvic9@...lbox.org>,
        Oleksandr Natalenko <oleksandr@...alenko.name>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Jonathan Corbet <corbet@....net>, linux-hwmon@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v11 1/2] hwmon: (asus_wmi_ec_sensors) Support B550 Asus WMI.

Linux HWMON sensors driver for ASUS motherboards to read
sensors from the embedded controller.

Many ASUS motherboards do not publish all the available
sensors via the Super I/O chip but the missing ones are
available through the embedded controller (EC) registers.

This driver implements reading those sensor data via the
WMI method BREC, which is known to be present in all ASUS
motherboards based on the AMD 500 series chipsets (and
probably is available in other models too). The driver
needs to know exact register addresses for the sensors and
thus support for each motherboard has to be added explicitly.

The EC registers do not provide critical values for the
sensors and as such they are not published to the HWMON.

Supported motherboards:
* PRIME X570-PRO
* Pro WS X570-ACE
* ROG CROSSHAIR VIII HERO
* ROG CROSSHAIR VIII DARK HERO
* ROG CROSSHAIR VIII FORMULA
* ROG STRIX X570-E GAMING
* ROG STRIX B550-I GAMING
* ROG STRIX B550-E GAMING

Signed-off-by: Denis Pauk <pauk.denis@...il.com>
Co-developed-by: Eugene Shalygin <eugene.shalygin@...il.com>
Signed-off-by: Eugene Shalygin <eugene.shalygin@...il.com>
Co-developed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Tested-by: Tor Vic <torvic9@...lbox.org>
Tested-by: Oleksandr Natalenko <oleksandr@...alenko.name>

---
Changes in v11:
- No changes.

Changes in v10:
- Use long for sensor values.
- Remove unrequired linux/hwmon-sysfs.h
- Add "ROG STRIX B550-I GAMING" board support.
- Change code style in error status return.

Changes in v9:
- Fix memory leaks in asus_wmi_ec_block_read()
- Fix buffer and parameter lengths in decode and encode algorithms
- Simplify encoding in read query
- Reshuffle structures to make pointer arithmetics simpler or
  no-op in some cases
- Shuffle parameters in some functions to make it more logical
- Use temporary variable for EC info data structure
- Many indentation fixes to improve readability (breaks 80 characters rule)

Changes in v8:
- Fix codestyle in defines and comments.
- Fix buffer length calculation.
- Use hex2bin/bin2hex for convert values in buffers.
- Remove unrequired acpi_os_free usage.
- Call mutex_lock inside of functions.

Changes in v7:
- Use dmi_first_match for directly get sensors list by board.
- Add depends on ACPI_WMI to Kconfig.
- Add response buffer size check in asus_wmi_ec_decode_reply_buffer.
- Clean up defines names.

Changes in v6:
- Generate query for all sensors on sensors setup
- Move binary to sensor value logic to separate get_sensor_value
  (by Eugene Shalygin)
- Add asus_wmi_ec_sensor to documentation index.
- Use acpi_os_free without NULL pointer check.

Changes in v5:
- Fixes build issue reported by kernel test robot with disabled ACPI_WMI.

Changes in v4:
 - implement wmi driver instead platform driver.

Changes in v3:
 - Use MODULE_DEVICE_TABLE for match devices.
 - Use get_unaligned_be32 instead incorrectly used get_unaligned_le32.
 - Add documentaion for driver.

Changes in v2:
 - Use utf8s_to_utf16s/utf16s_to_utf8s instead handmade fuctions.
 - Use post increment.
 - Use get_unaligned* for convert values.
 - Use PTR_ERR_OR_ZERO.
 - Specify per-board sensors in a declarative way (by Eugene Shalygin).
---
 Documentation/hwmon/asus_wmi_ec_sensors.rst |  38 ++
 Documentation/hwmon/index.rst               |   1 +
 MAINTAINERS                                 |   7 +
 drivers/hwmon/Kconfig                       |  12 +
 drivers/hwmon/Makefile                      |   1 +
 drivers/hwmon/asus_wmi_ec_sensors.c         | 621 ++++++++++++++++++++
 6 files changed, 680 insertions(+)
 create mode 100644 Documentation/hwmon/asus_wmi_ec_sensors.rst
 create mode 100644 drivers/hwmon/asus_wmi_ec_sensors.c

diff --git a/Documentation/hwmon/asus_wmi_ec_sensors.rst b/Documentation/hwmon/asus_wmi_ec_sensors.rst
new file mode 100644
index 000000000000..1b287f229e86
--- /dev/null
+++ b/Documentation/hwmon/asus_wmi_ec_sensors.rst
@@ -0,0 +1,38 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver asus_wmi_ec_sensors
+=================================
+
+Supported boards:
+ * PRIME X570-PRO,
+ * Pro WS X570-ACE,
+ * ROG CROSSHAIR VIII DARK HERO,
+ * ROG CROSSHAIR VIII FORMULA,
+ * ROG CROSSHAIR VIII HERO,
+ * ROG STRIX B550-E GAMING,
+ * ROG STRIX B550-I GAMING,
+ * ROG STRIX X570-E GAMING.
+
+Authors:
+    - Eugene Shalygin <eugene.shalygin@...il.com>
+
+Description:
+------------
+ASUS mainboards publish hardware monitoring information via Super I/O
+chip and the ACPI embedded controller (EC) registers. Some of the sensors
+are only available via the EC.
+
+ASUS WMI interface provides a method (BREC) to read data from EC registers,
+which is utilized by this driver to publish those sensor readings to the
+HWMON system. The driver is aware of and reads the following sensors:
+
+1. Chipset (PCH) temperature
+2. CPU package temperature
+3. Motherboard temperature
+4. Readings from the T_Sensor header
+5. VRM temperature
+6. CPU_Opt fan RPM
+7. Chipset fan RPM
+8. Readings from the "Water flow meter" header (RPM)
+9. Readings from the "Water In" and "Water Out" temperature headers
+10. CPU current
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 6f30c8c9c76a..3e196eaff360 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -43,6 +43,7 @@ Hardware Monitoring Kernel Drivers
    asb100
    asc7621
    aspeed-pwm-tacho
+   asus_wmi_ec_sensors
    bcm54140
    bel-pfe
    bpa-rs600
diff --git a/MAINTAINERS b/MAINTAINERS
index 7a2345ce8521..7a3812b8bbec 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2988,6 +2988,13 @@ W:	http://acpi4asus.sf.net
 F:	drivers/platform/x86/asus*.c
 F:	drivers/platform/x86/eeepc*.c
 
+ASUS WMI HARDWARE MONITOR DRIVER
+M:	Eugene Shalygin <eugene.shalygin@...il.com>
+M:	Denis Pauk <pauk.denis@...il.com>
+L:	linux-hwmon@...r.kernel.org
+S:	Maintained
+F:	drivers/hwmon/asus_wmi_ec_sensors.c
+
 ASUS WIRELESS RADIO CONTROL DRIVER
 M:	João Paulo Rechi Vita <jprvita@...il.com>
 L:	platform-driver-x86@...r.kernel.org
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 36e777de3565..81f5e2ddbdf5 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2228,6 +2228,18 @@ config SENSORS_ATK0110
 	  This driver can also be built as a module. If so, the module
 	  will be called asus_atk0110.
 
+config SENSORS_ASUS_WMI_EC
+	tristate "ASUS WMI B550/X570"
+	depends on ACPI_WMI
+	help
+	  If you say yes here you get support for the ACPI embedded controller
+	  hardware monitoring interface found in B550/X570 ASUS motherboards.
+	  This driver will provide readings of fans, voltages and temperatures
+	  through the system firmware.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called asus_wmi_sensors_ec.
+
 endif # ACPI
 
 endif # HWMON
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 1ddb26f57a6f..821345e49107 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_HWMON_VID)		+= hwmon-vid.o
 # APCI drivers
 obj-$(CONFIG_SENSORS_ACPI_POWER) += acpi_power_meter.o
 obj-$(CONFIG_SENSORS_ATK0110)	+= asus_atk0110.o
+obj-$(CONFIG_SENSORS_ASUS_WMI_EC)	+= asus_wmi_ec_sensors.o
 
 # Native drivers
 # asb100, then w83781d go first, as they can override other drivers' addresses.
diff --git a/drivers/hwmon/asus_wmi_ec_sensors.c b/drivers/hwmon/asus_wmi_ec_sensors.c
new file mode 100644
index 000000000000..f612abc66c89
--- /dev/null
+++ b/drivers/hwmon/asus_wmi_ec_sensors.c
@@ -0,0 +1,621 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * HWMON driver for ASUS B550/X570 motherboards that publish sensor
+ * values via the embedded controller registers.
+ *
+ * Copyright (C) 2021 Eugene Shalygin <eugene.shalygin@...il.com>
+ * Copyright (C) 2018-2019 Ed Brindley <kernel@...davale.org>
+ *
+ * EC provides:
+ * - Chipset temperature
+ * - CPU temperature
+ * - Motherboard temperature
+ * - T_Sensor temperature
+ * - VRM temperature
+ * - Water In temperature
+ * - Water Out temperature
+ * - CPU Optional Fan RPM
+ * - Chipset Fan RPM
+ * - Water Flow Fan RPM
+ * - CPU current
+ */
+
+#include <linux/acpi.h>
+#include <linux/dmi.h>
+#include <linux/hwmon.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/nls.h>
+#include <linux/units.h>
+#include <linux/wmi.h>
+
+#include <asm/unaligned.h>
+
+#define ASUSWMI_MONITORING_GUID		"466747A0-70EC-11DE-8A39-0800200C9A66"
+#define ASUSWMI_METHODID_BLOCK_READ_EC	0x42524543 /* BREC */
+/* From the ASUS DSDT source */
+#define ASUSWMI_BREC_REGISTERS_MAX	16
+#define ASUSWMI_MAX_BUF_LEN		128
+#define SENSOR_LABEL_LEN		16
+
+static u32 hwmon_attributes[] = {
+	[hwmon_chip]	= HWMON_C_REGISTER_TZ,
+	[hwmon_temp]	= HWMON_T_INPUT | HWMON_T_LABEL,
+	[hwmon_in]	= HWMON_I_INPUT | HWMON_I_LABEL,
+	[hwmon_curr]	= HWMON_C_INPUT | HWMON_C_LABEL,
+	[hwmon_fan]	= HWMON_F_INPUT | HWMON_F_LABEL,
+};
+
+struct asus_wmi_ec_sensor_address {
+	u8 index;
+	u8 bank;
+	u8 size;
+};
+
+#define MAKE_SENSOR_ADDRESS(size_i, bank_i, index_i) {	\
+	.size = size_i,					\
+	.bank = bank_i,					\
+	.index = index_i,				\
+}
+
+struct ec_sensor_info {
+	struct asus_wmi_ec_sensor_address addr;
+	char label[SENSOR_LABEL_LEN];
+	enum hwmon_sensor_types type;
+};
+
+#define EC_SENSOR(sensor_label, sensor_type, size, bank, index) {	\
+	.addr = MAKE_SENSOR_ADDRESS(size, bank, index),			\
+	.label = sensor_label,						\
+	.type = sensor_type,						\
+}
+
+enum known_ec_sensor {
+	SENSOR_TEMP_CHIPSET,
+	SENSOR_TEMP_CPU,
+	SENSOR_TEMP_MB,
+	SENSOR_TEMP_T_SENSOR,
+	SENSOR_TEMP_VRM,
+	SENSOR_FAN_CPU_OPT,
+	SENSOR_FAN_CHIPSET,
+	SENSOR_FAN_VRM_HS,
+	SENSOR_FAN_WATER_FLOW,
+	SENSOR_CURR_CPU,
+	SENSOR_TEMP_WATER_IN,
+	SENSOR_TEMP_WATER_OUT,
+	SENSOR_MAX
+};
+
+/* All known sensors for ASUS EC controllers */
+static const struct ec_sensor_info known_ec_sensors[] = {
+	[SENSOR_TEMP_CHIPSET]	= EC_SENSOR("Chipset", hwmon_temp, 1, 0x00, 0x3a),
+	[SENSOR_TEMP_CPU]	= EC_SENSOR("CPU", hwmon_temp, 1, 0x00, 0x3b),
+	[SENSOR_TEMP_MB]	= EC_SENSOR("Motherboard", hwmon_temp, 1, 0x00, 0x3c),
+	[SENSOR_TEMP_T_SENSOR]	= EC_SENSOR("T_Sensor", hwmon_temp, 1, 0x00, 0x3d),
+	[SENSOR_TEMP_VRM]	= EC_SENSOR("VRM", hwmon_temp, 1, 0x00, 0x3e),
+	[SENSOR_FAN_CPU_OPT]	= EC_SENSOR("CPU_Opt", hwmon_fan, 2, 0x00, 0xb0),
+	[SENSOR_FAN_VRM_HS]	= EC_SENSOR("VRM HS", hwmon_fan, 2, 0x00, 0xb2),
+	[SENSOR_FAN_CHIPSET]	= EC_SENSOR("Chipset", hwmon_fan, 2, 0x00, 0xb4),
+	[SENSOR_FAN_WATER_FLOW]	= EC_SENSOR("Water_Flow", hwmon_fan, 2, 0x00, 0xbc),
+	[SENSOR_CURR_CPU]	= EC_SENSOR("CPU", hwmon_curr, 1, 0x00, 0xf4),
+	[SENSOR_TEMP_WATER_IN]	= EC_SENSOR("Water_In", hwmon_temp, 1, 0x01, 0x00),
+	[SENSOR_TEMP_WATER_OUT]	= EC_SENSOR("Water_Out", hwmon_temp, 1, 0x01, 0x01),
+};
+
+struct asus_wmi_data {
+	const enum known_ec_sensor known_board_sensors[SENSOR_MAX + 1];
+};
+
+/* boards with EC support */
+static struct asus_wmi_data sensors_board_PW_X570_P = {
+	.known_board_sensors = {
+		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB, SENSOR_TEMP_VRM,
+		SENSOR_FAN_CHIPSET,
+		SENSOR_MAX
+	},
+};
+
+static struct asus_wmi_data sensors_board_PW_X570_A = {
+	.known_board_sensors = {
+		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB, SENSOR_TEMP_VRM,
+		SENSOR_FAN_CHIPSET,
+		SENSOR_CURR_CPU,
+		SENSOR_MAX
+	},
+};
+
+static struct asus_wmi_data sensors_board_R_C8H = {
+	.known_board_sensors = {
+		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
+		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
+		SENSOR_TEMP_WATER_IN, SENSOR_TEMP_WATER_OUT,
+		SENSOR_FAN_CPU_OPT, SENSOR_FAN_CHIPSET, SENSOR_FAN_WATER_FLOW,
+		SENSOR_CURR_CPU,
+		SENSOR_MAX
+	},
+};
+
+/* Same as Hero but without chipset fan */
+static struct asus_wmi_data sensors_board_R_C8DH = {
+	.known_board_sensors = {
+		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
+		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
+		SENSOR_TEMP_WATER_IN, SENSOR_TEMP_WATER_OUT,
+		SENSOR_FAN_CPU_OPT, SENSOR_FAN_WATER_FLOW,
+		SENSOR_CURR_CPU,
+		SENSOR_MAX
+	},
+};
+
+/* Same as Hero but without water */
+static struct asus_wmi_data sensors_board_R_C8F = {
+	.known_board_sensors = {
+		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
+		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
+		SENSOR_FAN_CPU_OPT, SENSOR_FAN_CHIPSET,
+		SENSOR_CURR_CPU,
+		SENSOR_MAX
+	},
+};
+
+static struct asus_wmi_data sensors_board_RS_B550_E_G = {
+	.known_board_sensors = {
+		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
+		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
+		SENSOR_FAN_CPU_OPT,
+		SENSOR_MAX
+	},
+};
+
+static struct asus_wmi_data sensors_board_RS_B550_I_G = {
+	.known_board_sensors = {
+		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
+		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
+		SENSOR_FAN_VRM_HS,
+		SENSOR_CURR_CPU,
+		SENSOR_MAX
+	},
+};
+
+static struct asus_wmi_data sensors_board_RS_X570_E_G = {
+	.known_board_sensors = {
+		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
+		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
+		SENSOR_FAN_CHIPSET,
+		SENSOR_CURR_CPU,
+		SENSOR_MAX
+	},
+};
+
+#define DMI_EXACT_MATCH_ASUS_BOARD_NAME(name, sensors) {			\
+	.matches = {								\
+		DMI_EXACT_MATCH(DMI_BOARD_VENDOR, "ASUSTeK COMPUTER INC."),	\
+		DMI_EXACT_MATCH(DMI_BOARD_NAME, name),				\
+	},									\
+	.driver_data = sensors,							\
+}
+
+static const struct dmi_system_id asus_wmi_ec_dmi_table[] = {
+	DMI_EXACT_MATCH_ASUS_BOARD_NAME("PRIME X570-PRO", &sensors_board_PW_X570_P),
+	DMI_EXACT_MATCH_ASUS_BOARD_NAME("Pro WS X570-ACE", &sensors_board_PW_X570_A),
+	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG CROSSHAIR VIII DARK HERO", &sensors_board_R_C8DH),
+	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG CROSSHAIR VIII FORMULA", &sensors_board_R_C8F),
+	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG CROSSHAIR VIII HERO", &sensors_board_R_C8H),
+	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG STRIX B550-E GAMING", &sensors_board_RS_B550_E_G),
+	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG STRIX B550-I GAMING", &sensors_board_RS_B550_I_G),
+	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG STRIX X570-E GAMING", &sensors_board_RS_X570_E_G),
+	{}
+};
+MODULE_DEVICE_TABLE(dmi, asus_wmi_ec_dmi_table);
+
+struct ec_sensor {
+	enum known_ec_sensor info_index;
+	long cached_value;
+};
+
+/**
+ * struct asus_wmi_ec_info - sensor info.
+ * @sensors: list of sensors.
+ * @read_arg: UTF-16LE string to pass to BRxx() WMI function.
+ * @read_buffer: decoded output from WMI result.
+ * @nr_sensors: number of board EC sensors.
+ * @nr_registers: number of EC registers to read (sensor might span more than 1 register).
+ * @last_updated: in jiffies.
+ */
+struct asus_wmi_ec_info {
+	struct ec_sensor sensors[SENSOR_MAX];
+	char read_arg[(ASUSWMI_BREC_REGISTERS_MAX * 4 + 1) * 2];
+	u8 read_buffer[ASUSWMI_BREC_REGISTERS_MAX];
+	unsigned int nr_sensors;
+	unsigned int nr_registers;
+	unsigned long last_updated;
+};
+
+struct asus_wmi_sensors {
+	struct asus_wmi_ec_info ec;
+	/* lock access to internal cache */
+	struct mutex lock;
+};
+
+static int asus_wmi_ec_fill_board_sensors(struct asus_wmi_ec_info *ec,
+					  const enum known_ec_sensor *bsi)
+{
+	struct ec_sensor *s = ec->sensors;
+	int i;
+
+	ec->nr_sensors = 0;
+	ec->nr_registers = 0;
+
+	for (i = 0; bsi[i] != SENSOR_MAX; i++) {
+		s[i].info_index = bsi[i];
+		ec->nr_sensors++;
+		ec->nr_registers += known_ec_sensors[bsi[i]].addr.size;
+	}
+
+	return 0;
+}
+
+/*
+ * The next four functions convert to or from BRxx string argument format.
+ * The format of the string is as follows:
+ * - The string consists of two-byte UTF-16LE characters.
+ * - The value of the very first byte in the string is equal to the total
+ *   length of the next string in bytes, thus excluding the first two-byte
+ *   character.
+ * - The rest of the string encodes the pairs of (bank, index) pairs, where
+ *   both values are byte-long (0x00 to 0xFF).
+ * - Numbers are encoded as UTF-16LE hex values.
+ */
+static int asus_wmi_ec_decode_reply_buffer(const u8 *in, u32 length, u8 *out)
+{
+	char buffer[ASUSWMI_MAX_BUF_LEN * 2];
+	u32 len = min_t(u32, get_unaligned_le16(in), length - 2);
+
+	utf16s_to_utf8s((wchar_t *)(in + 2), len / 2, UTF16_LITTLE_ENDIAN, buffer, sizeof(buffer));
+
+	return hex2bin(out, buffer, len / 4);
+}
+
+static void asus_wmi_ec_encode_registers(const u8 *in, u32 len, char *out)
+{
+	char buffer[ASUSWMI_MAX_BUF_LEN * 2];
+
+	bin2hex(buffer, in, len);
+
+	utf8s_to_utf16s(buffer, len * 2, UTF16_LITTLE_ENDIAN, (wchar_t *)(out + 2), len * 2);
+
+	put_unaligned_le16(len * 4, out);
+}
+
+static void asus_wmi_ec_make_block_read_query(struct asus_wmi_ec_info *ec)
+{
+	u8 registers[ASUSWMI_BREC_REGISTERS_MAX * 2];
+	const struct ec_sensor_info *si;
+	int i, j, offset;
+
+	offset = 0;
+	for (i = 0; i < ec->nr_sensors; i++) {
+		si = &known_ec_sensors[ec->sensors[i].info_index];
+		for (j = 0; j < si->addr.size; j++) {
+			registers[offset++] = si->addr.bank;
+			registers[offset++] = si->addr.index + j;
+		}
+	}
+
+	asus_wmi_ec_encode_registers(registers, offset, ec->read_arg);
+}
+
+static int asus_wmi_ec_block_read(u32 method_id, char *query, u8 *out)
+{
+	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
+	struct acpi_buffer input;
+	union acpi_object *obj;
+	acpi_status status;
+	int ret;
+
+	/* The first byte of the BRxx() argument string has to be the string size. */
+	input.length = query[0] + 2;
+	input.pointer = query;
+	status = wmi_evaluate_method(ASUSWMI_MONITORING_GUID, 0, method_id, &input, &output);
+	if (ACPI_FAILURE(status))
+		return -EIO;
+
+	obj = output.pointer;
+	if (!obj)
+		return -EIO;
+
+	if (obj->type != ACPI_TYPE_BUFFER || obj->buffer.length < 2) {
+		ret = -EIO;
+		goto out_free_obj;
+	}
+
+	ret = asus_wmi_ec_decode_reply_buffer(obj->buffer.pointer, obj->buffer.length, out);
+
+out_free_obj:
+	ACPI_FREE(obj);
+	return ret;
+}
+
+static inline long get_sensor_value(const struct ec_sensor_info *si, u8 *data)
+{
+	switch (si->addr.size) {
+	case 1:
+		return *data;
+	case 2:
+		return get_unaligned_be16(data);
+	case 4:
+		return get_unaligned_be32(data);
+	default:
+		return 0;
+	}
+}
+
+static void asus_wmi_ec_update_ec_sensors(struct asus_wmi_ec_info *ec)
+{
+	const struct ec_sensor_info *si;
+	struct ec_sensor *s;
+	u8 i_sensor;
+	u8 *data;
+
+	data = ec->read_buffer;
+	for (i_sensor = 0; i_sensor < ec->nr_sensors; i_sensor++) {
+		s = &ec->sensors[i_sensor];
+		si = &known_ec_sensors[s->info_index];
+		s->cached_value = get_sensor_value(si, data);
+		data += si->addr.size;
+	}
+}
+
+static long asus_wmi_ec_scale_sensor_value(long value, int data_type)
+{
+	switch (data_type) {
+	case hwmon_curr:
+	case hwmon_temp:
+	case hwmon_in:
+		return value * MILLI;
+	default:
+		return value;
+	}
+}
+
+static int asus_wmi_ec_find_sensor_index(const struct asus_wmi_ec_info *ec,
+					 enum hwmon_sensor_types type, int channel)
+{
+	int i;
+
+	for (i = 0; i < ec->nr_sensors; i++) {
+		if (known_ec_sensors[ec->sensors[i].info_index].type == type) {
+			if (channel == 0)
+				return i;
+
+			channel--;
+		}
+	}
+	return -EINVAL;
+}
+
+static int asus_wmi_ec_get_cached_value_or_update(struct asus_wmi_sensors *sensor_data,
+						  int sensor_index,
+						  long *value)
+{
+	struct asus_wmi_ec_info *ec = &sensor_data->ec;
+	int ret = 0;
+
+	mutex_lock(&sensor_data->lock);
+
+	if (time_after(jiffies, ec->last_updated + HZ)) {
+		ret = asus_wmi_ec_block_read(ASUSWMI_METHODID_BLOCK_READ_EC,
+					     ec->read_arg, ec->read_buffer);
+		if (ret)
+			goto unlock;
+
+		asus_wmi_ec_update_ec_sensors(ec);
+		ec->last_updated = jiffies;
+	}
+
+	*value = ec->sensors[sensor_index].cached_value;
+
+unlock:
+	mutex_unlock(&sensor_data->lock);
+
+	return ret;
+}
+
+/* Now follow the functions that implement the hwmon interface */
+
+static int asus_wmi_ec_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+				  u32 attr, int channel, long *val)
+{
+	struct asus_wmi_sensors *sensor_data = dev_get_drvdata(dev);
+	struct asus_wmi_ec_info *ec = &sensor_data->ec;
+	int ret, sidx, info_index;
+	long value = 0;
+
+	sidx = asus_wmi_ec_find_sensor_index(ec, type, channel);
+	if (sidx < 0)
+		return sidx;
+
+	ret = asus_wmi_ec_get_cached_value_or_update(sensor_data, sidx, &value);
+	if (ret)
+		return ret;
+
+	info_index = ec->sensors[sidx].info_index;
+	*val = asus_wmi_ec_scale_sensor_value(value, known_ec_sensors[info_index].type);
+
+	return ret;
+}
+
+static int asus_wmi_ec_hwmon_read_string(struct device *dev,
+					 enum hwmon_sensor_types type, u32 attr,
+					 int channel, const char **str)
+{
+	struct asus_wmi_sensors *sensor_data = dev_get_drvdata(dev);
+	struct asus_wmi_ec_info *ec = &sensor_data->ec;
+	int sensor_index;
+
+	sensor_index = asus_wmi_ec_find_sensor_index(ec, type, channel);
+	*str = known_ec_sensors[ec->sensors[sensor_index].info_index].label;
+
+	return 0;
+}
+
+static umode_t asus_wmi_ec_hwmon_is_visible(const void *drvdata,
+					    enum hwmon_sensor_types type, u32 attr,
+					    int channel)
+{
+	const struct asus_wmi_sensors *sensor_data = drvdata;
+	const struct asus_wmi_ec_info *ec = &sensor_data->ec;
+	int index;
+
+	index = asus_wmi_ec_find_sensor_index(ec, type, channel);
+
+	return index < 0 ? 0 : 0444;
+}
+
+static int asus_wmi_hwmon_add_chan_info(struct hwmon_channel_info *asus_wmi_hwmon_chan,
+					struct device *dev, int num,
+					enum hwmon_sensor_types type, u32 config)
+{
+	u32 *cfg;
+
+	cfg = devm_kcalloc(dev, num + 1, sizeof(*cfg), GFP_KERNEL);
+	if (!cfg)
+		return -ENOMEM;
+
+	asus_wmi_hwmon_chan->type = type;
+	asus_wmi_hwmon_chan->config = cfg;
+	memset32(cfg, config, num);
+
+	return 0;
+}
+
+static const struct hwmon_ops asus_wmi_ec_hwmon_ops = {
+	.is_visible = asus_wmi_ec_hwmon_is_visible,
+	.read = asus_wmi_ec_hwmon_read,
+	.read_string = asus_wmi_ec_hwmon_read_string,
+};
+
+static struct hwmon_chip_info asus_wmi_ec_chip_info = {
+	.ops = &asus_wmi_ec_hwmon_ops,
+};
+
+static int asus_wmi_ec_configure_sensor_setup(struct device *dev,
+					      const enum known_ec_sensor *bsi)
+{
+	struct asus_wmi_sensors *sensor_data = dev_get_drvdata(dev);
+	struct asus_wmi_ec_info *ec = &sensor_data->ec;
+	struct hwmon_channel_info *asus_wmi_hwmon_chan;
+	const struct hwmon_channel_info **asus_wmi_ci;
+	int nr_count[hwmon_max] = {}, nr_types = 0;
+	const struct hwmon_chip_info *chip_info;
+	const struct ec_sensor_info *si;
+	enum hwmon_sensor_types type;
+	struct device *hwdev;
+	int i, ret;
+
+	ret = asus_wmi_ec_fill_board_sensors(ec, bsi);
+	if (ret)
+		return ret;
+
+	if (!sensor_data->ec.nr_sensors)
+		return -ENODEV;
+
+	for (i = 0; i < ec->nr_sensors; i++) {
+		si = &known_ec_sensors[ec->sensors[i].info_index];
+		if (!nr_count[si->type])
+			nr_types++;
+		nr_count[si->type]++;
+	}
+
+	if (nr_count[hwmon_temp]) {
+		nr_count[hwmon_chip]++;
+		nr_types++;
+	}
+
+	/*
+	 * If we can get values for all the registers in a single query,
+	 * the query will not change from call to call.
+	 */
+	asus_wmi_ec_make_block_read_query(ec);
+
+	asus_wmi_hwmon_chan = devm_kcalloc(dev, nr_types, sizeof(*asus_wmi_hwmon_chan),
+					   GFP_KERNEL);
+	if (!asus_wmi_hwmon_chan)
+		return -ENOMEM;
+
+	asus_wmi_ci = devm_kcalloc(dev, nr_types + 1, sizeof(*asus_wmi_ci), GFP_KERNEL);
+	if (!asus_wmi_ci)
+		return -ENOMEM;
+
+	asus_wmi_ec_chip_info.info = asus_wmi_ci;
+	chip_info = &asus_wmi_ec_chip_info;
+
+	for (type = 0; type < hwmon_max; type++) {
+		if (!nr_count[type])
+			continue;
+
+		ret = asus_wmi_hwmon_add_chan_info(asus_wmi_hwmon_chan, dev,
+						   nr_count[type], type,
+						   hwmon_attributes[type]);
+		if (ret)
+			return ret;
+
+		*asus_wmi_ci++ = asus_wmi_hwmon_chan++;
+	}
+
+	dev_dbg(dev, "board has %d EC sensors that span %d registers",
+		ec->nr_sensors, ec->nr_registers);
+
+	hwdev = devm_hwmon_device_register_with_info(dev, "asus_wmi_ec_sensors",
+						     sensor_data, chip_info, NULL);
+
+	return PTR_ERR_OR_ZERO(hwdev);
+}
+
+static int asus_wmi_probe(struct wmi_device *wdev, const void *context)
+{
+	struct asus_wmi_sensors *sensor_data;
+	struct asus_wmi_data *board_sensors;
+	const struct dmi_system_id *dmi_id;
+	const enum known_ec_sensor *bsi;
+	struct device *dev = &wdev->dev;
+
+	dmi_id = dmi_first_match(asus_wmi_ec_dmi_table);
+	if (!dmi_id)
+		return -ENODEV;
+
+	board_sensors = dmi_id->driver_data;
+	bsi = board_sensors->known_board_sensors;
+
+	sensor_data = devm_kzalloc(dev, sizeof(*sensor_data), GFP_KERNEL);
+	if (!sensor_data)
+		return -ENOMEM;
+
+	mutex_init(&sensor_data->lock);
+
+	dev_set_drvdata(dev, sensor_data);
+
+	return asus_wmi_ec_configure_sensor_setup(dev, bsi);
+}
+
+static const struct wmi_device_id asus_ec_wmi_id_table[] = {
+	{ ASUSWMI_MONITORING_GUID, NULL },
+	{ }
+};
+
+static struct wmi_driver asus_sensors_wmi_driver = {
+	.driver = {
+		.name = "asus_wmi_ec_sensors",
+	},
+	.id_table = asus_ec_wmi_id_table,
+	.probe = asus_wmi_probe,
+};
+module_wmi_driver(asus_sensors_wmi_driver);
+
+MODULE_AUTHOR("Ed Brindley <kernel@...davale.org>");
+MODULE_AUTHOR("Eugene Shalygin <eugene.shalygin@...il.com>");
+MODULE_DESCRIPTION("Asus WMI Sensors Driver");
+MODULE_LICENSE("GPL");
-- 
2.33.0

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