[PATCH 2/3] hwmon: (asus-ec-sensors) add fan extension card fans for MAXIMUS IX EXTREME
From: Remy Demangeot via B4 Relay
Date: Mon Oct 26 2026 - 05:00:00 EST
From: Remy Demangeot <remy@xxxxxxxxxxxxx>
On the MAXIMUS IX EXTREME, the speeds of the three fans on the
optional ASUS fan extension card (EXT_FAN1-3) are not at fixed EC
addresses. Bank 0 register 0x43 selects which fan a group of registers
describes: after writing 0x0a, 0x0b or 0x0c to it, registers 0x57:0x58
hold the RPM of EXT_FAN1, EXT_FAN2 or EXT_FAN3 (big-endian).
Allow a sensor definition to carry a selector value, using the unused
byte of sensor_address. When reading such a register, the driver
writes the selector first and restores the previous selector value
once the bank has been read. Sensors without a selector are read as
before.
Readings match HWiNFO 8.54 on the same machine, and follow the fan
speed when the fan duty is changed.
Signed-off-by: Remy Demangeot <remy@xxxxxxxxxxxxx>
---
drivers/hwmon/asus-ec-sensors.c | 75 ++++++++++++++++++++++++++++++++++++-----
1 file changed, 66 insertions(+), 9 deletions(-)
diff --git a/drivers/hwmon/asus-ec-sensors.c b/drivers/hwmon/asus-ec-sensors.c
index 8966053b58173592a19afbab42ccbe8e6e6d7042..11dd7f587530d640b6ccc9b7952dc9da47e11c19 100644
--- a/drivers/hwmon/asus-ec-sensors.c
+++ b/drivers/hwmon/asus-ec-sensors.c
@@ -40,6 +40,11 @@ static char *mutex_path_override;
/* Writing to this EC register switches EC bank */
#define ASUS_EC_BANK_REGISTER 0xff
+/*
+ * On some boards, writing to this bank 0 register selects which device a
+ * group of registers reports (e.g. one of the fans of the fan extension card).
+ */
+#define ASUS_EC_SELECT_REGISTER 0x43
#define SENSOR_LABEL_LEN 16
/*
@@ -73,7 +78,8 @@ typedef union {
u8 index;
u8 bank;
u8 size;
- u8 dummy;
+ /* value to write to ASUS_EC_SELECT_REGISTER first, 0 if none */
+ u8 select;
} components;
} sensor_address;
@@ -81,6 +87,11 @@ typedef union {
.value = (size << 16) + (bank << 8) + index \
}
+#define MAKE_SENSOR_ADDRESS_SELECT(size, bank, index, select) { \
+ .value = ((u32)(select) << 24) + ((size) << 16) + \
+ ((bank) << 8) + (index) \
+ }
+
static u32 hwmon_attributes[hwmon_max] = {
[hwmon_chip] = HWMON_C_REGISTER_TZ,
[hwmon_temp] = HWMON_T_INPUT | HWMON_T_LABEL,
@@ -100,6 +111,12 @@ struct ec_sensor_info {
.addr = MAKE_SENSOR_ADDRESS(size, bank, index), \
}
+/* A sensor read after writing @select to ASUS_EC_SELECT_REGISTER */
+#define EC_SENSOR_SELECT(sensor_label, sensor_type, size, bank, index, select) {\
+ .label = sensor_label, .type = sensor_type, \
+ .addr = MAKE_SENSOR_ADDRESS_SELECT(size, bank, index, select), \
+ }
+
enum ec_sensors {
/* chipset temperature [℃] */
ec_sensor_temp_chipset,
@@ -155,6 +172,10 @@ enum ec_sensors {
ec_sensor_temp_sensor_extra_2,
/* "Extra_3" temperature sensor reading [℃] */
ec_sensor_temp_sensor_extra_3,
+ /* fan extension card fans [RPM] */
+ ec_sensor_fan_ext_1,
+ ec_sensor_fan_ext_2,
+ ec_sensor_fan_ext_3,
};
#define SENSOR_TEMP_CHIPSET BIT(ec_sensor_temp_chipset)
@@ -184,6 +205,9 @@ enum ec_sensors {
#define SENSOR_TEMP_SENSOR_EXTRA_1 BIT(ec_sensor_temp_sensor_extra_1)
#define SENSOR_TEMP_SENSOR_EXTRA_2 BIT(ec_sensor_temp_sensor_extra_2)
#define SENSOR_TEMP_SENSOR_EXTRA_3 BIT(ec_sensor_temp_sensor_extra_3)
+#define SENSOR_FAN_EXT_1 BIT(ec_sensor_fan_ext_1)
+#define SENSOR_FAN_EXT_2 BIT(ec_sensor_fan_ext_2)
+#define SENSOR_FAN_EXT_3 BIT(ec_sensor_fan_ext_3)
/*
* The values for temperature sensor readings without physical sensors connected.
@@ -367,6 +391,12 @@ static const struct ec_sensor_info sensors_family_intel_200[] = {
EC_SENSOR("Extra_3", hwmon_temp, 1, 0x00, 0x62),
[ec_sensor_fan_cpu_opt] =
EC_SENSOR("CPU_Opt", hwmon_fan, 2, 0x00, 0xbc),
+ [ec_sensor_fan_ext_1] =
+ EC_SENSOR_SELECT("EXT_FAN1", hwmon_fan, 2, 0x00, 0x57, 0x0a),
+ [ec_sensor_fan_ext_2] =
+ EC_SENSOR_SELECT("EXT_FAN2", hwmon_fan, 2, 0x00, 0x57, 0x0b),
+ [ec_sensor_fan_ext_3] =
+ EC_SENSOR_SELECT("EXT_FAN3", hwmon_fan, 2, 0x00, 0x57, 0x0c),
};
static const struct ec_sensor_info sensors_family_intel_300[] = {
@@ -530,7 +560,8 @@ static const struct ec_board_info board_info_maximus_vi_hero = {
static const struct ec_board_info board_info_maximus_ix_extreme = {
.sensors = SENSOR_TEMP_CHIPSET | SENSOR_TEMP_T_SENSOR |
SENSOR_TEMP_VRM | SENSOR_TEMP_SENSOR_EXTRA_1 |
- SENSOR_TEMP_SENSOR_EXTRA_2 | SENSOR_TEMP_SENSOR_EXTRA_3,
+ SENSOR_TEMP_SENSOR_EXTRA_2 | SENSOR_TEMP_SENSOR_EXTRA_3 |
+ SENSOR_FAN_EXT_1 | SENSOR_FAN_EXT_2 | SENSOR_FAN_EXT_3,
.mutex_path = ASUS_HW_ACCESS_MUTEX_SB_PCI0_LPCB_SIO1_MUT0,
.family = family_intel_200_series,
};
@@ -1074,8 +1105,11 @@ struct ec_sensors_data {
const struct ec_board_info *board_info;
const struct ec_sensor_info *sensors_info;
struct ec_sensor *sensors;
- /* EC registers to read from */
- u16 *registers;
+ /*
+ * EC registers to read from: (select << 16) + (bank << 8) + index,
+ * see register_select()
+ */
+ u32 *registers;
u8 *read_buffer;
/* sorted list of unique register banks */
u8 banks[ASUS_EC_MAX_BANK + 1];
@@ -1093,16 +1127,21 @@ struct ec_sensors_data {
u8 nr_banks;
};
-static u8 register_bank(u16 reg)
+static u8 register_bank(u32 reg)
{
- return reg >> 8;
+ return (reg >> 8) & 0xff;
}
-static u8 register_index(u16 reg)
+static u8 register_index(u32 reg)
{
return reg & 0x00ff;
}
+static u8 register_select(u32 reg)
+{
+ return (reg >> 16) & 0xff;
+}
+
static bool is_sensor_data_signed(const struct ec_sensor_info *si)
{
/*
@@ -1185,6 +1224,7 @@ static void fill_ec_registers(struct ec_sensors_data *ec)
si = get_sensor_info(ec, i);
for (j = 0; j < si->addr.components.size; ++j, ++register_idx) {
ec->registers[register_idx] =
+ (si->addr.components.select << 16) +
(si->addr.components.bank << 8) +
si->addr.components.index + j;
}
@@ -1239,7 +1279,8 @@ static int asus_ec_block_read(const struct device *dev,
struct ec_sensors_data *ec)
{
int ireg, ibank, status;
- u8 bank, reg_bank, prev_bank;
+ u8 bank, reg_bank, prev_bank, select, prev_select;
+ bool select_saved;
bank = 0;
status = asus_ec_bank_switch(bank, &prev_bank);
@@ -1264,14 +1305,30 @@ static int asus_ec_block_read(const struct device *dev,
break;
}
}
+ select_saved = false;
for (ireg = 0; ireg < ec->nr_registers; ireg++) {
reg_bank = register_bank(ec->registers[ireg]);
if (reg_bank != bank) {
continue;
}
+ select = register_select(ec->registers[ireg]);
+ if (select) {
+ if (!select_saved) {
+ if (ec_read(ASUS_EC_SELECT_REGISTER,
+ &prev_select))
+ continue;
+ select_saved = true;
+ }
+ if (ec_write(ASUS_EC_SELECT_REGISTER, select))
+ continue;
+ }
ec_read(register_index(ec->registers[ireg]),
ec->read_buffer + ireg);
}
+ /* restore the selector while still in its bank */
+ if (select_saved &&
+ ec_write(ASUS_EC_SELECT_REGISTER, prev_select))
+ dev_warn(dev, "EC selector restore failed");
}
status = asus_ec_bank_switch(prev_bank, NULL);
@@ -1556,7 +1613,7 @@ static int asus_ec_probe(struct platform_device *pdev)
setup_sensor_data(ec_data);
ec_data->registers = devm_kcalloc(dev, ec_data->nr_registers,
- sizeof(u16), GFP_KERNEL);
+ sizeof(*ec_data->registers), GFP_KERNEL);
ec_data->read_buffer = devm_kcalloc(dev, ec_data->nr_registers,
sizeof(u8), GFP_KERNEL);
--
2.47.3