[PATCH 2/2] hwmon: axiado-tsadc: Add AX3000/AX3005 TSADC support
Petar Stepanovic
pstepanovic at axiado.com
Thu Sep 3 00:09:48 PDT 2026
Add a hwmon driver for the temperature sensor ADC (TSADC) controller
found on Axiado AX3000 and AX3005 SoCs. The controller measures
temperature at locations within the SoC silicon die.
Each TSADC controller is registered as a separate hwmon device and
exposes one read-only temperature channel. The sensor is configured for
continuous conversion during probe.
The current TSADC hardware does not support threshold or alarm reporting.
All TSADC interrupt sources are masked during initialization, and only
the current temperature is exposed through temp1_input.
The averaged 12-bit ADC code is converted to millidegrees Celsius using
a lookup table with linear interpolation between adjacent entries. Raw
values outside the characterized lookup-table range are clamped to the
nearest supported temperature.
Signed-off-by: Petar Stepanovic <pstepanovic at axiado.com>
---
Documentation/hwmon/axiado-tsadc.rst | 41 ++++++
Documentation/hwmon/index.rst | 1 +
MAINTAINERS | 2 +
drivers/hwmon/Kconfig | 11 ++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/axiado-tsadc.c | 275 +++++++++++++++++++++++++++++++++++
6 files changed, 331 insertions(+)
diff --git a/Documentation/hwmon/axiado-tsadc.rst b/Documentation/hwmon/axiado-tsadc.rst
new file mode 100644
index 000000000000..b8fd0aeacc1f
--- /dev/null
+++ b/Documentation/hwmon/axiado-tsadc.rst
@@ -0,0 +1,41 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver axiado-tsadc
+==========================
+
+Supported chips:
+
+ * Axiado AX3000 and AX3005 on-chip temperature sensor (TSADC)
+
+ Prefix: 'axiado_tsadc'
+
+ Addresses scanned: -
+
+ Datasheet: Not publicly available
+
+Authors:
+
+ - Petar Stepanovic <pstepanovic at axiado.com>
+
+Description
+-----------
+
+This driver supports the Temperature Sensor ADC (TSADC) block found on Axiado
+AX3000 and AX3005 SoCs. The block monitors the on-die temperature of the SoC.
+
+An SoC may instantiate several TSADC blocks at different locations on the die.
+Each block is described by its own device tree node and is registered as a
+separate hwmon device with a single temperature channel.
+
+The sensor is configured for continuous conversion at probe time, averaging
+16 samples per conversion. The averaged 12-bit ADC code is converted to
+millidegrees Celsius using a lookup table with linear interpolation between
+entries. The table covers -40 to +125 degrees Celsius; readings outside that
+range are clamped to the nearest supported temperature.
+
+sysfs entries
+-------------
+
+======================= =======================================================
+temp1_input Die temperature in millidegrees Celsius (read-only)
+======================= =======================================================
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index d979e6d6e9f2..b79a27aeb4b4 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -51,6 +51,7 @@ Hardware Monitoring Kernel Drivers
asus_ec_sensors
asus_rog_ryujin
asus_wmi_sensors
+ axiado-tsadc
bcm54140
bel-pfe
bpa-rs600
diff --git a/MAINTAINERS b/MAINTAINERS
index c6efb04fc376..3108a004439f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4474,6 +4474,8 @@ M: Prasad Bolisetty <pbolisetty at axiado.com>
L: linux-hwmon at vger.kernel.org
S: Supported
F: Documentation/devicetree/bindings/hwmon/axiado,ax3000-tsadc.yaml
+F: Documentation/hwmon/axiado-tsadc.rst
+F: drivers/hwmon/axiado-tsadc.c
AYANEO PLATFORM EC DRIVER
M: Antheas Kapenekakis <lkml at antheas.dev>
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 81a9a1d40eec..f12a47e70f0c 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -311,6 +311,17 @@ config SENSORS_AXI_FAN_CONTROL
This driver can also be built as a module. If so, the module
will be called axi-fan-control
+config SENSORS_AXIADO_TSADC
+ tristate "Axiado AX3000 TSADC temperature sensor"
+ depends on ARCH_AXIADO || COMPILE_TEST
+ help
+ If you say yes here you get support for the on-chip temperature
+ sensor (TSADC) found on Axiado AX3000 and AX3005 SoCs. The die
+ temperature is reported through the hwmon sysfs interface.
+
+ This driver can also be built as a module. If so, the module
+ will be called axiado-tsadc.
+
config SENSORS_K8TEMP
tristate "AMD Athlon64/FX or Opteron temperature sensor"
depends on X86 && PCI
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 0cad7e21634c..b5f5d18e1ccf 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_SENSORS_ASPEED_G6) += aspeed-g6-pwm-tach.o
obj-$(CONFIG_SENSORS_ASUS_ROG_RYUJIN) += asus_rog_ryujin.o
obj-$(CONFIG_SENSORS_ATXP1) += atxp1.o
obj-$(CONFIG_SENSORS_AXI_FAN_CONTROL) += axi-fan-control.o
+obj-$(CONFIG_SENSORS_AXIADO_TSADC) += axiado-tsadc.o
obj-$(CONFIG_SENSORS_CGBC) += cgbc-hwmon.o
obj-$(CONFIG_SENSORS_CHIPCAP2) += chipcap2.o
obj-$(CONFIG_SENSORS_CORETEMP) += coretemp.o
diff --git a/drivers/hwmon/axiado-tsadc.c b/drivers/hwmon/axiado-tsadc.c
new file mode 100644
index 000000000000..c111df6f0044
--- /dev/null
+++ b/drivers/hwmon/axiado-tsadc.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021-2026 Axiado Corporation
+ *
+ * Driver for the Axiado on-chip temperature sensor (TSADC)
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+/* TSADC register offsets */
+#define AXIADO_TSADC_MODE 0x0000
+#define AXIADO_TSADC_FUNC_CTRL 0x0004
+#define AXIADO_TSADC_AVG_DOUT 0x000c
+#define AXIADO_TSADC_INTR_MASK 0x0010
+#define AXIADO_TSADC_ANA_REG 0x0020
+#define AXIADO_TSADC_SEL 0x0028
+#define AXIADO_TSADC_TSEN_EN 0x002c
+#define AXIADO_TSADC_EN 0x0030
+
+/* TSADC mode register: continuous conversion */
+#define AXIADO_TSADC_MODE_CONT 0x2
+
+/*
+ * TSADC functional control register: bit 0 starts the conversion and
+ * bits [31:16] specify the number of samples. Average over 16 samples.
+ */
+#define AXIADO_TSADC_FUNC_CTRL_START BIT(0)
+#define AXIADO_TSADC_FUNC_CTRL_NUM_SAMPLES GENMASK(31, 16)
+#define AXIADO_TSADC_FUNC_CTRL_CLR 0x0
+#define AXIADO_TSADC_FUNC_CTRL_SET \
+ (FIELD_PREP(AXIADO_TSADC_FUNC_CTRL_NUM_SAMPLES, 16) | \
+ AXIADO_TSADC_FUNC_CTRL_START)
+
+/* TSADC average output register: 12-bit ADC result */
+#define AXIADO_TSADC_AVG_DOUT_MASK GENMASK(11, 0)
+
+/* Interrupt mask bits */
+#define AXIADO_TSADC_INTR_BIST_DONE BIT(0)
+#define AXIADO_TSADC_INTR_LOOP_DONE BIT(1)
+#define AXIADO_TSADC_INTR_THRESHOLD BIT(2)
+#define AXIADO_TSADC_INTR_MASK_ALL \
+ (AXIADO_TSADC_INTR_BIST_DONE | \
+ AXIADO_TSADC_INTR_LOOP_DONE | \
+ AXIADO_TSADC_INTR_THRESHOLD)
+
+/* TSADC analog block configuration required for temperature measurement */
+#define AXIADO_TSADC_ANA_REG_INIT 0x6
+
+/* TSADC SEL: select temperature measurement */
+#define AXIADO_TSADC_SEL_TEMP 0x00
+
+/* TSADC EN / TSEN_EN field values */
+#define AXIADO_TSADC_DIS 0x00
+#define AXIADO_TSADC_ENA 0x01
+
+struct axiado_tsadc {
+ void __iomem *regs;
+};
+
+/*
+ * Lookup table: raw ADC output (12-bit) vs temperature in millidegrees
+ * Celsius. Raw values decrease as temperature increases, from -40°C
+ * to 125°C in 5°C steps.
+ */
+struct axiado_tsadc_point {
+ u32 raw;
+ int temp_mc;
+};
+
+static const struct axiado_tsadc_point axiado_tsadc_table[] = {
+ { .raw = 2776, .temp_mc = -40000 },
+ { .raw = 2748, .temp_mc = -35000 },
+ { .raw = 2721, .temp_mc = -30000 },
+ { .raw = 2694, .temp_mc = -25000 },
+ { .raw = 2667, .temp_mc = -20000 },
+ { .raw = 2640, .temp_mc = -15000 },
+ { .raw = 2612, .temp_mc = -10000 },
+ { .raw = 2584, .temp_mc = -5000 },
+ { .raw = 2556, .temp_mc = 0 },
+ { .raw = 2528, .temp_mc = 5000 },
+ { .raw = 2500, .temp_mc = 10000 },
+ { .raw = 2472, .temp_mc = 15000 },
+ { .raw = 2444, .temp_mc = 20000 },
+ { .raw = 2416, .temp_mc = 25000 },
+ { .raw = 2389, .temp_mc = 30000 },
+ { .raw = 2362, .temp_mc = 35000 },
+ { .raw = 2335, .temp_mc = 40000 },
+ { .raw = 2307, .temp_mc = 45000 },
+ { .raw = 2279, .temp_mc = 50000 },
+ { .raw = 2251, .temp_mc = 55000 },
+ { .raw = 2223, .temp_mc = 60000 },
+ { .raw = 2195, .temp_mc = 65000 },
+ { .raw = 2167, .temp_mc = 70000 },
+ { .raw = 2138, .temp_mc = 75000 },
+ { .raw = 2110, .temp_mc = 80000 },
+ { .raw = 2081, .temp_mc = 85000 },
+ { .raw = 2052, .temp_mc = 90000 },
+ { .raw = 2024, .temp_mc = 95000 },
+ { .raw = 1996, .temp_mc = 100000 },
+ { .raw = 1967, .temp_mc = 105000 },
+ { .raw = 1938, .temp_mc = 110000 },
+ { .raw = 1909, .temp_mc = 115000 },
+ { .raw = 1880, .temp_mc = 120000 },
+ { .raw = 1852, .temp_mc = 125000 },
+};
+
+/* Convert raw ADC code to millidegrees Celsius with linear interpolation. */
+static int axiado_tsadc_raw_to_mc(u32 raw, long *val)
+{
+ int i, n = ARRAY_SIZE(axiado_tsadc_table);
+ long num, denom;
+
+ if (raw >= axiado_tsadc_table[0].raw) {
+ *val = axiado_tsadc_table[0].temp_mc;
+ return 0;
+ }
+
+ if (raw <= axiado_tsadc_table[n - 1].raw) {
+ *val = axiado_tsadc_table[n - 1].temp_mc;
+ return 0;
+ }
+
+ /* Find i such that axiado_tsadc_table[i].raw >= raw > axiado_tsadc_table[i+1].raw */
+ for (i = 0; i < n - 1; i++) {
+ if (raw >= axiado_tsadc_table[i + 1].raw)
+ break;
+ }
+
+ if (raw == axiado_tsadc_table[i].raw) {
+ *val = axiado_tsadc_table[i].temp_mc;
+ return 0;
+ }
+
+ /* Linear interpolation within the interval */
+ num = (long)(axiado_tsadc_table[i + 1].temp_mc - axiado_tsadc_table[i].temp_mc) *
+ (axiado_tsadc_table[i].raw - raw);
+ denom = axiado_tsadc_table[i].raw - axiado_tsadc_table[i + 1].raw;
+ *val = axiado_tsadc_table[i].temp_mc + num / denom;
+ return 0;
+}
+
+static int axiado_tsadc_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct axiado_tsadc *tsadc = dev_get_drvdata(dev);
+ u32 raw;
+
+ if (type != hwmon_temp)
+ return -EOPNOTSUPP;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ if (ioread32(tsadc->regs + AXIADO_TSADC_SEL) != AXIADO_TSADC_SEL_TEMP ||
+ ioread32(tsadc->regs + AXIADO_TSADC_EN) != AXIADO_TSADC_ENA)
+ return -ENODATA;
+
+ raw = ioread32(tsadc->regs + AXIADO_TSADC_AVG_DOUT) &
+ AXIADO_TSADC_AVG_DOUT_MASK;
+
+ return axiado_tsadc_raw_to_mc(raw, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static umode_t axiado_tsadc_is_visible(const void *data,
+ enum hwmon_sensor_types type, u32 attr,
+ int channel)
+{
+ if (type == hwmon_temp) {
+ switch (attr) {
+ case hwmon_temp_input:
+ return 0444;
+ default:
+ break;
+ }
+ }
+
+ return 0;
+}
+
+static const struct hwmon_channel_info * const axiado_tsadc_info[] = {
+ HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+ NULL
+};
+
+static const struct hwmon_ops axiado_tsadc_hwmon_ops = {
+ .is_visible = axiado_tsadc_is_visible,
+ .read = axiado_tsadc_read,
+};
+
+static const struct hwmon_chip_info axiado_tsadc_chip_info = {
+ .ops = &axiado_tsadc_hwmon_ops,
+ .info = axiado_tsadc_info,
+};
+
+static void axiado_tsadc_disable(void *data)
+{
+ struct axiado_tsadc *tsadc = data;
+
+ iowrite32(AXIADO_TSADC_DIS, tsadc->regs + AXIADO_TSADC_TSEN_EN);
+ iowrite32(AXIADO_TSADC_DIS, tsadc->regs + AXIADO_TSADC_EN);
+}
+
+static int axiado_tsadc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct axiado_tsadc *tsadc;
+ struct device *hwmon_dev;
+ struct clk *refclk;
+ int ret;
+
+ tsadc = devm_kzalloc(dev, sizeof(*tsadc), GFP_KERNEL);
+ if (!tsadc)
+ return -ENOMEM;
+
+ tsadc->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(tsadc->regs))
+ return dev_err_probe(dev, PTR_ERR(tsadc->regs),
+ "failed to map registers\n");
+
+ refclk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(refclk))
+ return dev_err_probe(dev, PTR_ERR(refclk),
+ "failed to enable reference clock\n");
+
+ /* Mask all interrupts before setup */
+ iowrite32(AXIADO_TSADC_INTR_MASK_ALL, tsadc->regs + AXIADO_TSADC_INTR_MASK);
+
+ iowrite32(AXIADO_TSADC_ANA_REG_INIT, tsadc->regs + AXIADO_TSADC_ANA_REG);
+ iowrite32(AXIADO_TSADC_ENA, tsadc->regs + AXIADO_TSADC_EN);
+ iowrite32(AXIADO_TSADC_SEL_TEMP, tsadc->regs + AXIADO_TSADC_SEL);
+ iowrite32(AXIADO_TSADC_MODE_CONT, tsadc->regs + AXIADO_TSADC_MODE);
+ iowrite32(AXIADO_TSADC_FUNC_CTRL_CLR, tsadc->regs + AXIADO_TSADC_FUNC_CTRL);
+ iowrite32(AXIADO_TSADC_FUNC_CTRL_SET, tsadc->regs + AXIADO_TSADC_FUNC_CTRL);
+
+ /* Enable the bandgap circuit once the block is fully configured */
+ iowrite32(AXIADO_TSADC_ENA, tsadc->regs + AXIADO_TSADC_TSEN_EN);
+
+ ret = devm_add_action_or_reset(dev, axiado_tsadc_disable, tsadc);
+ if (ret)
+ return ret;
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev, "axiado_tsadc",
+ tsadc,
+ &axiado_tsadc_chip_info,
+ NULL);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct of_device_id axiado_tsadc_match[] = {
+ { .compatible = "axiado,ax3000-tsadc" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, axiado_tsadc_match);
+
+static struct platform_driver axiado_tsadc_driver = {
+ .driver = {
+ .name = "axiado-tsadc",
+ .of_match_table = axiado_tsadc_match,
+ },
+ .probe = axiado_tsadc_probe,
+};
+module_platform_driver(axiado_tsadc_driver);
+
+MODULE_DESCRIPTION("Axiado TSADC temperature sensor driver");
+MODULE_AUTHOR("Axiado Corporation");
+MODULE_LICENSE("GPL");
--
2.34.1
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