hwmon: Add LattePanda Sigma EC driver
Add hardware monitoring support for the LattePanda Sigma SBC (DFRobot, ITE IT8613E EC). The driver reads fan speed and temperatures via direct port I/O, as the BIOS disables the ACPI EC interface. Signed-off-by: Mariano Abad <weimaraner@gmail.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net>master
Mariano Abad
Guenter Roeck
parent
afc6c4aede
commit
a28b088ede
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@ -110,6 +110,7 @@ Hardware Monitoring Kernel Drivers
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kbatt
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kfan
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lan966x
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lattepanda-sigma-ec
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lineage-pem
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lm25066
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lm63
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@ -0,0 +1,61 @@
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.. SPDX-License-Identifier: GPL-2.0-or-later
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Kernel driver lattepanda-sigma-ec
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=================================
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Supported systems:
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* LattePanda Sigma (Intel 13th Gen i5-1340P)
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DMI vendor: LattePanda
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DMI product: LattePanda Sigma
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BIOS version: 5.27 (verified)
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Datasheet: Not available (EC registers discovered empirically)
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Author: Mariano Abad <weimaraner@gmail.com>
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Description
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-----------
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This driver provides hardware monitoring for the LattePanda Sigma
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single-board computer made by DFRobot. The board uses an ITE IT8613E
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Embedded Controller to manage a CPU cooling fan and thermal sensors.
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The BIOS declares the ACPI Embedded Controller (``PNP0C09``) with
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``_STA`` returning 0, preventing the kernel's ACPI EC subsystem from
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initializing. This driver reads the EC directly via the standard ACPI
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EC I/O ports (``0x62`` data, ``0x66`` command/status).
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Sysfs attributes
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----------------
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======================= ===============================================
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``fan1_input`` Fan speed in RPM (EC registers 0x2E:0x2F,
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16-bit big-endian)
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``fan1_label`` "CPU Fan"
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``temp1_input`` Board/ambient temperature in millidegrees
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Celsius (EC register 0x60, unsigned)
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``temp1_label`` "Board Temp"
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``temp2_input`` CPU proximity temperature in millidegrees
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Celsius (EC register 0x70, unsigned)
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``temp2_label`` "CPU Temp"
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======================= ===============================================
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Module parameters
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-----------------
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``force`` (bool, default false)
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Force loading on BIOS versions other than 5.27. The driver still
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requires DMI vendor and product name matching.
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Known limitations
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-----------------
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* Fan speed control is not supported. The fan is always under EC
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automatic control.
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* The EC register map was verified only on BIOS version 5.27.
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Other versions may use different register offsets; use the ``force``
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parameter at your own risk.
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@ -14421,6 +14421,13 @@ F: drivers/net/wan/framer/
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F: drivers/pinctrl/pinctrl-pef2256.c
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F: include/linux/framer/
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LATTEPANDA SIGMA EC HARDWARE MONITOR DRIVER
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M: Mariano Abad <weimaraner@gmail.com>
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L: linux-hwmon@vger.kernel.org
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S: Maintained
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F: Documentation/hwmon/lattepanda-sigma-ec.rst
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F: drivers/hwmon/lattepanda-sigma-ec.c
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LASI 53c700 driver for PARISC
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M: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
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L: linux-scsi@vger.kernel.org
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@ -964,6 +964,23 @@ config SENSORS_LAN966X
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This driver can also be built as a module. If so, the module
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will be called lan966x-hwmon.
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config SENSORS_LATTEPANDA_SIGMA_EC
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tristate "LattePanda Sigma EC hardware monitoring"
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depends on X86
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depends on DMI
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depends on HAS_IOPORT
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help
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If you say yes here you get support for the hardware monitoring
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features of the Embedded Controller on LattePanda Sigma
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single-board computers, including CPU fan speed (RPM) and
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board and CPU temperatures.
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The driver reads the EC directly via ACPI EC I/O ports and
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uses DMI matching to ensure it only loads on supported hardware.
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This driver can also be built as a module. If so, the module
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will be called lattepanda-sigma-ec.
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config SENSORS_LENOVO_EC
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tristate "Sensor reader for Lenovo ThinkStations"
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depends on X86
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@ -113,6 +113,7 @@ obj-$(CONFIG_SENSORS_K10TEMP) += k10temp.o
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obj-$(CONFIG_SENSORS_KBATT) += kbatt.o
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obj-$(CONFIG_SENSORS_KFAN) += kfan.o
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obj-$(CONFIG_SENSORS_LAN966X) += lan966x-hwmon.o
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obj-$(CONFIG_SENSORS_LATTEPANDA_SIGMA_EC) += lattepanda-sigma-ec.o
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obj-$(CONFIG_SENSORS_LENOVO_EC) += lenovo-ec-sensors.o
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obj-$(CONFIG_SENSORS_LINEAGE) += lineage-pem.o
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obj-$(CONFIG_SENSORS_LOCHNAGAR) += lochnagar-hwmon.o
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@ -0,0 +1,359 @@
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Hardware monitoring driver for LattePanda Sigma EC.
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*
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* The LattePanda Sigma is an x86 SBC made by DFRobot with an ITE IT8613E
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* Embedded Controller that manages a CPU fan and thermal sensors.
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*
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* The BIOS declares the ACPI Embedded Controller (PNP0C09) with _STA
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* returning 0 and provides only stub ECRD/ECWT methods that return Zero
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* for all registers. Since the kernel's ACPI EC subsystem never initializes,
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* ec_read() is not available and direct port I/O to the standard ACPI EC
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* ports (0x62/0x66) is used instead.
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*
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* Because ACPI never initializes the EC, there is no concurrent firmware
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* access to these ports, and no ACPI Global Lock or namespace mutex is
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* required. The hwmon with_info API serializes all sysfs callbacks,
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* so no additional driver-level locking is needed.
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*
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* The EC register map was discovered by dumping all 256 registers,
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* identifying those that change in real-time, and validating by physically
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* stopping the fan and observing the RPM register drop to zero. The map
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* has been verified on BIOS version 5.27; other versions may differ.
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*
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* Copyright (c) 2026 Mariano Abad <weimaraner@gmail.com>
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*/
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#include <linux/delay.h>
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#include <linux/dmi.h>
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#include <linux/hwmon.h>
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#include <linux/io.h>
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#include <linux/ioport.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#define DRIVER_NAME "lattepanda_sigma_ec"
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/* EC I/O ports (standard ACPI EC interface) */
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#define EC_DATA_PORT 0x62
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#define EC_CMD_PORT 0x66 /* also status port */
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/* EC commands */
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#define EC_CMD_READ 0x80
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/* EC status register bits */
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#define EC_STATUS_OBF 0x01 /* Output Buffer Full */
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#define EC_STATUS_IBF 0x02 /* Input Buffer Full */
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/* EC register offsets for LattePanda Sigma (BIOS 5.27) */
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#define EC_REG_FAN_RPM_HI 0x2E
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#define EC_REG_FAN_RPM_LO 0x2F
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#define EC_REG_TEMP_BOARD 0x60
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#define EC_REG_TEMP_CPU 0x70
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#define EC_REG_FAN_DUTY 0x93
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/*
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* EC polling uses udelay() because the EC typically responds within a
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* few microseconds. The kernel's own ACPI EC driver (drivers/acpi/ec.c)
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* likewise uses udelay() for busy-polling with a per-poll delay of 550us.
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*
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* usleep_range() was tested but caused EC protocol failures: the EC
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* clears its status flags within microseconds, and sleeping for 50-100us
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* between polls allowed the flags to transition past the expected state.
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*
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* The worst-case total busy-wait of 25ms covers EC recovery after errors.
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* In practice the EC responds within 10us so the loop exits immediately.
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*/
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#define EC_TIMEOUT_US 25000
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#define EC_POLL_US 1
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static bool force;
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module_param(force, bool, 0444);
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MODULE_PARM_DESC(force,
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"Force loading on untested BIOS versions (default: false)");
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static struct platform_device *lps_ec_pdev;
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static int ec_wait_ibf_clear(void)
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{
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int i;
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for (i = 0; i < EC_TIMEOUT_US; i++) {
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if (!(inb(EC_CMD_PORT) & EC_STATUS_IBF))
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return 0;
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udelay(EC_POLL_US);
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}
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return -ETIMEDOUT;
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}
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static int ec_wait_obf_set(void)
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{
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int i;
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for (i = 0; i < EC_TIMEOUT_US; i++) {
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if (inb(EC_CMD_PORT) & EC_STATUS_OBF)
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return 0;
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udelay(EC_POLL_US);
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}
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return -ETIMEDOUT;
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}
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static int ec_read_reg(u8 reg, u8 *val)
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{
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int ret;
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ret = ec_wait_ibf_clear();
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if (ret)
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return ret;
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outb(EC_CMD_READ, EC_CMD_PORT);
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ret = ec_wait_ibf_clear();
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if (ret)
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return ret;
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outb(reg, EC_DATA_PORT);
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ret = ec_wait_obf_set();
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if (ret)
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return ret;
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*val = inb(EC_DATA_PORT);
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return 0;
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}
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/*
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* Read a 16-bit big-endian value from two consecutive EC registers.
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*
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* The EC may update the register pair between reading the high and low
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* bytes, which could produce a corrupted value if the high byte rolls
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* over (e.g., 0x0100 -> 0x00FF read as 0x01FF). Guard against this by
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* re-reading the high byte after reading the low byte. If the high byte
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* changed, re-read the low byte to get a consistent pair.
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* See also lm90_read16() which uses the same approach.
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*/
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static int ec_read_reg16(u8 reg_hi, u8 reg_lo, u16 *val)
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{
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int ret;
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u8 oldh, newh, lo;
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ret = ec_read_reg(reg_hi, &oldh);
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if (ret)
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return ret;
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ret = ec_read_reg(reg_lo, &lo);
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if (ret)
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return ret;
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ret = ec_read_reg(reg_hi, &newh);
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if (ret)
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return ret;
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if (oldh != newh) {
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ret = ec_read_reg(reg_lo, &lo);
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if (ret)
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return ret;
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}
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*val = ((u16)newh << 8) | lo;
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return 0;
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}
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static int
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lps_ec_read_string(struct device *dev,
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enum hwmon_sensor_types type,
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u32 attr, int channel,
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const char **str)
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{
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switch (type) {
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case hwmon_fan:
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*str = "CPU Fan";
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return 0;
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case hwmon_temp:
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*str = channel == 0 ? "Board Temp" : "CPU Temp";
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return 0;
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default:
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return -EOPNOTSUPP;
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}
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}
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static umode_t
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lps_ec_is_visible(const void *drvdata,
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enum hwmon_sensor_types type,
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u32 attr, int channel)
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{
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switch (type) {
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case hwmon_fan:
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if (attr == hwmon_fan_input || attr == hwmon_fan_label)
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return 0444;
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break;
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case hwmon_temp:
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if (attr == hwmon_temp_input || attr == hwmon_temp_label)
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return 0444;
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break;
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default:
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break;
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}
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return 0;
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}
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static int
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lps_ec_read(struct device *dev,
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enum hwmon_sensor_types type,
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u32 attr, int channel, long *val)
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{
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u16 rpm;
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u8 v;
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int ret;
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switch (type) {
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case hwmon_fan:
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if (attr != hwmon_fan_input)
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return -EOPNOTSUPP;
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ret = ec_read_reg16(EC_REG_FAN_RPM_HI,
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EC_REG_FAN_RPM_LO, &rpm);
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if (ret)
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return ret;
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*val = rpm;
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return 0;
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case hwmon_temp:
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if (attr != hwmon_temp_input)
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return -EOPNOTSUPP;
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ret = ec_read_reg(channel == 0 ? EC_REG_TEMP_BOARD
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: EC_REG_TEMP_CPU,
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&v);
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if (ret)
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return ret;
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/* EC reports unsigned 8-bit temperature in degrees Celsius */
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*val = (unsigned long)v * 1000;
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return 0;
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default:
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return -EOPNOTSUPP;
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}
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}
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static const struct hwmon_channel_info * const lps_ec_info[] = {
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HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_LABEL),
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HWMON_CHANNEL_INFO(temp,
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HWMON_T_INPUT | HWMON_T_LABEL,
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HWMON_T_INPUT | HWMON_T_LABEL),
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NULL
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};
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static const struct hwmon_ops lps_ec_ops = {
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.is_visible = lps_ec_is_visible,
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.read = lps_ec_read,
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.read_string = lps_ec_read_string,
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};
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static const struct hwmon_chip_info lps_ec_chip_info = {
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.ops = &lps_ec_ops,
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.info = lps_ec_info,
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};
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static int lps_ec_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device *hwmon;
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u8 test;
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int ret;
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if (!devm_request_region(dev, EC_DATA_PORT, 1, DRIVER_NAME))
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return dev_err_probe(dev, -EBUSY,
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"Failed to request EC data port 0x%x\n",
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EC_DATA_PORT);
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if (!devm_request_region(dev, EC_CMD_PORT, 1, DRIVER_NAME))
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return dev_err_probe(dev, -EBUSY,
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"Failed to request EC cmd port 0x%x\n",
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EC_CMD_PORT);
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/* Sanity check: verify EC is responsive */
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ret = ec_read_reg(EC_REG_FAN_DUTY, &test);
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if (ret)
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return dev_err_probe(dev, ret,
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"EC not responding on ports 0x%x/0x%x\n",
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EC_DATA_PORT, EC_CMD_PORT);
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hwmon = devm_hwmon_device_register_with_info(dev, DRIVER_NAME, NULL,
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&lps_ec_chip_info, NULL);
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if (IS_ERR(hwmon))
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return dev_err_probe(dev, PTR_ERR(hwmon),
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"Failed to register hwmon device\n");
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dev_info(dev, "EC hwmon registered (fan duty: %u%%)\n", test);
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return 0;
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}
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/* DMI table with strict BIOS version match (override with force=1) */
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static const struct dmi_system_id lps_ec_dmi_table[] = {
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{
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.ident = "LattePanda Sigma",
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.matches = {
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DMI_MATCH(DMI_SYS_VENDOR, "LattePanda"),
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DMI_MATCH(DMI_PRODUCT_NAME, "LattePanda Sigma"),
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DMI_MATCH(DMI_BIOS_VERSION, "5.27"),
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},
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},
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{ } /* terminator */
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};
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MODULE_DEVICE_TABLE(dmi, lps_ec_dmi_table);
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/* Loose table (vendor + product only) for use with force=1 */
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static const struct dmi_system_id lps_ec_dmi_table_force[] = {
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{
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.ident = "LattePanda Sigma",
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.matches = {
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DMI_MATCH(DMI_SYS_VENDOR, "LattePanda"),
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DMI_MATCH(DMI_PRODUCT_NAME, "LattePanda Sigma"),
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},
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},
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{ } /* terminator */
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};
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static struct platform_driver lps_ec_driver = {
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.probe = lps_ec_probe,
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.driver = {
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.name = DRIVER_NAME,
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},
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};
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static int __init lps_ec_init(void)
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{
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int ret;
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if (!dmi_check_system(lps_ec_dmi_table)) {
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if (!force || !dmi_check_system(lps_ec_dmi_table_force))
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return -ENODEV;
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pr_warn("%s: BIOS version not verified, loading due to force=1\n",
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DRIVER_NAME);
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}
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ret = platform_driver_register(&lps_ec_driver);
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if (ret)
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return ret;
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lps_ec_pdev = platform_device_register_simple(DRIVER_NAME, -1,
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NULL, 0);
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if (IS_ERR(lps_ec_pdev)) {
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platform_driver_unregister(&lps_ec_driver);
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return PTR_ERR(lps_ec_pdev);
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}
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return 0;
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}
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static void __exit lps_ec_exit(void)
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{
|
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platform_device_unregister(lps_ec_pdev);
|
||||
platform_driver_unregister(&lps_ec_driver);
|
||||
}
|
||||
|
||||
module_init(lps_ec_init);
|
||||
module_exit(lps_ec_exit);
|
||||
|
||||
MODULE_AUTHOR("Mariano Abad <weimaraner@gmail.com>");
|
||||
MODULE_DESCRIPTION("Hardware monitoring driver for LattePanda Sigma EC");
|
||||
MODULE_LICENSE("GPL");
|
||||
Loading…
Reference in New Issue