[PATCH v7 0/2] Add driver support for ESWIN EIC7700 PVT controller

[PATCH v7 0/2] Add driver support for ESWIN EIC7700 PVT controller

[hehuan1]

From: Huan He <hehuan1@eswincomputing.com>

Add support for the ESWIN EIC7700 PVT (Voltage, Temperature) sensor

Features:
The driver supports monitoring of voltage and temperature parameters
through the hardware monitoring subsystem. It provides an access to the
sampled Temperature and Voltage.

Test:
Tested this patch on the SiFive HiFive Premier P550 (which uses the ESWIN
EIC7700 SoC).

Updates:

  Changes in v7:
  - Remove the unused reset control pointer from struct pvt_hwmon and keep
    the reset control handle local to eic7700_pvt_probe()
  - Update eic7700_pvt_init_iface() to disable PVT_ENA_EN before clearing
    the interrupt status, preventing a possible level-triggered interrupt
    storm if the bootloader leaves the conversion engine running
  - Update eic7700_pvt_disable_pm_runtime() to explicitly disable runtime
    PM and avoid an unbalanced disable_depth

  Changes in v6:
  - Fix the !CONFIG_PM probe error path by disabling the clock if IRQ
    request fails before the PM cleanup action is registered
  - Replace pm_runtime_put_noidle() with pm_runtime_put() in the IRQ
    handler to avoid a runtime PM reference-count race with the read path
  - Remove the unused pvt_clear_data() devres action and its associated
    devm_add_action() registration

  Changes in v5:
  - Update eswin,eic7700-pvt.yaml
    - Drop the label enum constraint and remove label from the required
      list
    - Add '#thermal-sensor-cells' to the required list
    - Rename the example node to the generic sensor@... form
    - Update the binding description to describe one temperature sensor
      and one voltage sensor
  - Update eic7700-pvt.c
    - Register the hwmon device with the fixed name "pvt"
    - Remove label-based instance identification from the driver
    - Fix CONFIG_PM=n support by keeping the clock enabled when runtime PM
      is unavailable
    - Add pm_runtime_force_suspend() in the cleanup path to avoid leaving
      the device active during unbind
    - Switch system sleep callbacks to pm_runtime_force_suspend() and
      pm_runtime_force_resume()
    - Guard ISR register accesses with pm_runtime_get_if_active()
    - Add synchronize_irq() on the timeout path to avoid stale completion
      races
    - Remove temp_offset support because the raw trim register does not
      match the hwmon ABI
    - Align the commit message with the implementation (one temperature
      sensor, one voltage sensor)

  Changes in v4:
  - Update eswin,eic7700-pvt.yaml
    - Delete reviewed-by tag of Conor Dooley, because the label enum
      constraint is introduced
  - Update eic7700-pvt.c and eic7700-pvt.h
    - Remove the unused LVT/ULVT/SVT process-monitoring channels
    - Remove the probe-time power check since the PVT block is always
      powered on EIC7700 and the extra verification is unnecessary
    - Stop requesting the interrupt as shared and use the dedicated PVT IRQ
      only
    - Reorder probe initialization so the interface is initialized before
      the clock is disabled, avoiding register accesses with the clock gated
    - Fix runtime PM reference handling on error paths by balancing
      pm_runtime_get_noresume() with pm_runtime_put_noidle()
    - Add pm_runtime_put_noidle() handling for failed pm_runtime_get_sync()
      calls in hwmon read/write paths
    - Switch the PM callback registration from pm_sleep_ptr() to pm_ptr()

  Changes in v3:
  - Update eswin,eic7700-pvt.yaml
    - Remove redundant label property description and use 'label: true' to
      reference the definition in hwmon-common.yaml
    - Replace 'additionalProperties: false' with
      'unevaluatedProperties: false'
    - Remove the description for '#thermal-sensor-cells'
  - Update eic7700-pvt.c and eic7700-pvt.h
    - Fix clock reference count imbalance with Runtime PM:
      Replace devm_clk_get_enabled() with devm_clk_get() and manually
      manage clock enable/disable to avoid double-disable in remove() when
      Runtime PM is active. Clock is now enabled only during probe for
      eic7700_pvt_check_pwr(), then disabled before enabling Runtime PM,
      which takes full control of the clock thereafter
    - Add detailed comment explaining the spurious interrupt risk in
      eic7700_pvt_check_pwr()
    - Replace wait_for_completion_interruptible() with
      wait_for_completion_timeout() to prevent infinite wait

  Changes in v2:
  - Update eswin,eic7700-pvt.yaml
    - Reference the hwmon-common.yaml file
    - Remove the clock-names and reset-names properties
    - Move additionalProperties: false after the required block
    - Remove one example node to avoid redundancy
  - Update eic7700-pvt.c and eic7700-pvt.h
    - Remove unused sensor macros (PVT_SENSOR_FIRST, PVT_SENSOR_LAST,
      PVT_SENSORS_NUM)
    - Drop the unnecessary hwmon-sysfs.h header
    - Replace dynamic sensor info allocation with a static array and unify
      sensor labels
    - Remove unused hwmon_temp_type attribute
    - Eliminate redundant validation checks
    - Remove mutex and related locking, relying on hwmon core
      serialization
    - Replace per-sensor caches and completions with a single data cache
      and completion object
    - Remove pvt->sensor tracking. ISR no longer depends on the currently
      selected sensor
    - Move devm_add_action() registration after init_completion() for
      safer cleanup, and update cleanup function (pvt_clear_data)
    - Replace devm_reset_control_get_optional_exclusive() with
      devm_reset_control_get_exclusive_deasserted()
    - Replace eic7700_pvt_remove() with eic7700_pvt_disable_pm_runtime()
      and move it after PM runtime enable to avoid resource leaks on probe
      failure and remove clock disable and reset assert from
      eic7700_pvt_disable_pm_runtime() as it is already handled by devm_*
      framework
    - Remove redundant clock presence check in runtime_resume

  - Link to v1: https://lore.kernel.org/all/20260109090718.442-1-hehuan1@eswincomputing.com/

Huan He (2):
  dt-bindings: hwmon: Add Eswin EIC7700 PVT sensor
  hwmon: Add Eswin EIC7700 PVT sensor driver

 .../bindings/hwmon/eswin,eic7700-pvt.yaml     |  63 +++
 drivers/hwmon/Kconfig                         |  12 +
 drivers/hwmon/Makefile                        |   1 +
 drivers/hwmon/eic7700-pvt.c                   | 497 ++++++++++++++++++
 drivers/hwmon/eic7700-pvt.h                   |  98 ++++
 5 files changed, 671 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/eswin,eic7700-pvt.yaml
 create mode 100644 drivers/hwmon/eic7700-pvt.c
 create mode 100644 drivers/hwmon/eic7700-pvt.h

-- 
2.25.1

[PATCH v7 1/2] dt-bindings: hwmon: Add Eswin EIC7700 PVT sensor

[hehuan1]

From: Huan He <hehuan1@eswincomputing.com>

Add device tree binding documentation for ESWIN EIC7700 Voltage and
Temperature sensor.

The EIC7700 SoC integrates two PVT instances for monitoring SoC and DDR
power domains respectively.

Signed-off-by: Yulin Lu <luyulin@eswincomputing.com>
Signed-off-by: Huan He <hehuan1@eswincomputing.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
 .../bindings/hwmon/eswin,eic7700-pvt.yaml     | 63 +++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/eswin,eic7700-pvt.yaml

diff --git a/Documentation/devicetree/bindings/hwmon/eswin,eic7700-pvt.yaml b/Documentation/devicetree/bindings/hwmon/eswin,eic7700-pvt.yaml
new file mode 100644
index 000000000000..27cc90e52d4b
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/eswin,eic7700-pvt.yaml
@@ -0,0 +1,63 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/eswin,eic7700-pvt.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ESWIN EIC7700 PVT Sensor
+
+maintainers:
+  - Yulin Lu <luyulin@eswincomputing.com>
+  - Huan He <hehuan1@eswincomputing.com>
+
+description:
+  ESWIN EIC7700 SoC integrates embedded voltage and temperature sensors to
+  monitor the internal SoC environment. The system includes two PVT sensor
+  instances. The PVT0 monitors the main SoC power domain. The PVT1 sensor
+  monitors the DDR core power domain.
+
+allOf:
+  - $ref: /schemas/hwmon/hwmon-common.yaml#
+
+properties:
+  compatible:
+    const: eswin,eic7700-pvt
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  '#thermal-sensor-cells':
+    const: 0
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - interrupts
+  - resets
+  - '#thermal-sensor-cells'
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    sensor@50b00000 {
+      compatible = "eswin,eic7700-pvt";
+      reg = <0x50b00000 0x10000>;
+      clocks = <&clocks 244>;
+      interrupts = <349>;
+      interrupt-parent = <&plic>;
+      label = "pvt0";
+      resets = <&reset 111>;
+      #thermal-sensor-cells = <0>;
+    };
+...
-- 
2.25.1

[PATCH v7 2/2] hwmon: Add Eswin EIC7700 PVT sensor driver

[hehuan1]

From: Huan He <hehuan1@eswincomputing.com>

Add support for ESWIN EIC7700 Voltage and Temperature sensor. The driver
supports temperature and voltage monitoring with polynomial conversion,
and provides sysfs interface for sensor data access.

The PVT IP contains one temperature sensor and one voltage sensor.

Signed-off-by: Yulin Lu <luyulin@eswincomputing.com>
Signed-off-by: Huan He <hehuan1@eswincomputing.com>
---
 drivers/hwmon/Kconfig       |  12 +
 drivers/hwmon/Makefile      |   1 +
 drivers/hwmon/eic7700-pvt.c | 497 ++++++++++++++++++++++++++++++++++++
 drivers/hwmon/eic7700-pvt.h |  98 +++++++
 4 files changed, 608 insertions(+)
 create mode 100644 drivers/hwmon/eic7700-pvt.c
 create mode 100644 drivers/hwmon/eic7700-pvt.h

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 14e4cea48acc..6cb60355aa0c 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2033,6 +2033,18 @@ config SENSORS_DME1737
 	  This driver can also be built as a module. If so, the module
 	  will be called dme1737.
 
+config SENSORS_EIC7700_PVT
+	tristate "Eswin EIC7700 Voltage, Temperature sensor driver"
+	depends on ARCH_ESWIN || COMPILE_TEST
+	depends on HWMON
+	select POLYNOMIAL
+	help
+	  If you say yes here you get support for Eswin EIC7700 PVT sensor
+	  embedded into the SoC.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called eic7700-pvt.
+
 config SENSORS_EMC1403
 	tristate "SMSC EMC1403/23 thermal sensor"
 	depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 982ee2c6f9de..d647669074e1 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -71,6 +71,7 @@ obj-$(CONFIG_SENSORS_DME1737)	+= dme1737.o
 obj-$(CONFIG_SENSORS_DRIVETEMP)	+= drivetemp.o
 obj-$(CONFIG_SENSORS_DS620)	+= ds620.o
 obj-$(CONFIG_SENSORS_DS1621)	+= ds1621.o
+obj-$(CONFIG_SENSORS_EIC7700_PVT) += eic7700-pvt.o
 obj-$(CONFIG_SENSORS_EMC1403)	+= emc1403.o
 obj-$(CONFIG_SENSORS_EMC2103)	+= emc2103.o
 obj-$(CONFIG_SENSORS_EMC2305)	+= emc2305.o
diff --git a/drivers/hwmon/eic7700-pvt.c b/drivers/hwmon/eic7700-pvt.c
new file mode 100644
index 000000000000..3b3aed74c394
--- /dev/null
+++ b/drivers/hwmon/eic7700-pvt.c
@@ -0,0 +1,497 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ESWIN EIC7700 Voltage, Temperature sensor driver
+ *
+ * Copyright 2026, Beijing ESWIN Computing Technology Co., Ltd.
+ *
+ * Authors:
+ *   Yulin Lu <luyulin@eswincomputing.com>
+ *   Huan He <hehuan1@eswincomputing.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/polynomial.h>
+#include <linux/reset.h>
+#include "eic7700-pvt.h"
+
+static const struct pvt_sensor_info pvt_info[] = {
+	PVT_SENSOR_INFO(0, "Temperature", hwmon_temp, TEMP),
+	PVT_SENSOR_INFO(0, "Voltage", hwmon_in, VOLT),
+};
+
+/*
+ * The original translation formulae of the temperature (in degrees of Celsius)
+ * to PVT data and vice-versa are following:
+ * N = 6.0818e-8*(T^4) +1.2873e-5*(T^3) + 7.2244e-3*(T^2) + 3.6484*(T^1) +
+ *     1.6198e2,
+ * T = -1.8439e-11*(N^4) + 8.0705e-8*(N^3) + -1.8501e-4*(N^2) +
+ *     3.2843e-1*(N^1) - 4.8690e1,
+ * where T = [-40, 125]C and N = [27, 771].
+ * They must be accordingly altered to be suitable for the integer arithmetics.
+ * The technique is called 'factor redistribution', which just makes sure the
+ * multiplications and divisions are made so to have a result of the operations
+ * within the integer numbers limit. In addition we need to translate the
+ * formulae to accept millidegrees of Celsius. Here what they look like after
+ * the alterations:
+ * N = (60818e-20*(T^4) + 12873e-14*(T^3) + 72244e-9*(T^2) + 36484e-3*T +
+ *     16198e2) / 1e4,
+ * T = -18439e-12*(N^4) + 80705e-9*(N^3) - 185010e-6*(N^2) + 328430e-3*N -
+ *     48690,
+ * where T = [-40000, 125000] mC and N = [27, 771].
+ */
+static const struct polynomial poly_N_to_temp = {
+	.total_divider = 1,
+	.terms = {
+		{4, -18439, 1000, 1},
+		{3, 80705, 1000, 1},
+		{2, -185010, 1000, 1},
+		{1, 328430, 1000, 1},
+		{0, -48690, 1, 1}
+	}
+};
+
+/*
+ * Similar alterations are performed for the voltage conversion equations.
+ * The original formulae are:
+ * N = 1.3905e3*V - 5.7685e2,
+ * V = (N + 5.7685e2) / 1.3905e3,
+ * where V = [0.72, 0.88] V and N = [424, 646].
+ * After the optimization they looks as follows:
+ * N = (13905e-3*V - 5768.5) / 10,
+ * V = (N * 10^5 / 13905 + 57685 * 10^3 / 13905) / 10.
+ * where V = [720, 880] mV and N = [424, 646].
+ */
+static const struct polynomial poly_N_to_volt = {
+	.total_divider = 10,
+	.terms = {
+		{1, 100000, 13905, 1},
+		{0, 57685000, 1, 13905}
+	}
+};
+
+static inline u32 eic7700_pvt_update(void __iomem *reg, u32 mask, u32 data)
+{
+	u32 old;
+
+	old = readl_relaxed(reg);
+	writel((old & ~mask) | (data & mask), reg);
+
+	return old & mask;
+}
+
+static inline void eic7700_pvt_set_mode(struct pvt_hwmon *pvt, u32 mode)
+{
+	u32 old;
+
+	mode = FIELD_PREP(PVT_MODE_MASK, mode);
+
+	old = eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, 0);
+	eic7700_pvt_update(pvt->regs + PVT_MODE, PVT_MODE_MASK, mode);
+	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, old);
+}
+
+static inline void eic7700_pvt_set_trim(struct pvt_hwmon *pvt, u32 val)
+{
+	u32 old;
+
+	old = eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, 0);
+	writel(val, pvt->regs + PVT_TRIM);
+	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, old);
+}
+
+static irqreturn_t eic7700_pvt_hard_isr(int irq, void *data)
+{
+	struct pvt_hwmon *pvt = data;
+	int active;
+	u32 val;
+
+	if (IS_ENABLED(CONFIG_PM)) {
+		active = pm_runtime_get_if_active(pvt->dev);
+		if (active <= 0)
+			return IRQ_NONE;
+	}
+
+	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);
+	/*
+	 * Read the data, update the cache and notify a waiter of this event.
+	 */
+	val = readl(pvt->regs + PVT_DATA);
+	WRITE_ONCE(pvt->data_cache, FIELD_GET(PVT_DATA_OUT, val));
+	complete(&pvt->conversion);
+
+	if (IS_ENABLED(CONFIG_PM))
+		pm_runtime_put(pvt->dev);
+
+	return IRQ_HANDLED;
+}
+
+static int eic7700_pvt_read_data(struct pvt_hwmon *pvt,
+				 enum pvt_sensor_type type, long *val)
+{
+	unsigned long timeout;
+	u32 data;
+	int ret;
+
+	/*
+	 * Wait for PVT conversion to complete and update the data cache. The
+	 * data read procedure is following: set the requested PVT sensor mode,
+	 * enable conversion, wait until conversion is finished, then disable
+	 * conversion and IRQ, and read the cached data.
+	 */
+	reinit_completion(&pvt->conversion);
+
+	eic7700_pvt_set_mode(pvt, pvt_info[type].mode);
+	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, PVT_ENA_EN);
+
+	/*
+	 * Wait with timeout since in case if the sensor is suddenly powered
+	 * down the request won't be completed and the caller will hang up on
+	 * this procedure until the power is back up again. Multiply the
+	 * timeout by the factor of two to prevent a false timeout.
+	 */
+	timeout = 2 * usecs_to_jiffies(ktime_to_us(pvt->timeout));
+	ret = wait_for_completion_timeout(&pvt->conversion, timeout);
+
+	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, 0);
+	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);
+
+	if (!ret)
+		synchronize_irq(pvt->irq);
+
+	data = READ_ONCE(pvt->data_cache);
+
+	if (!ret)
+		return -ETIMEDOUT;
+
+	if (type == PVT_TEMP)
+		*val = polynomial_calc(&poly_N_to_temp, data);
+	else
+		*val = polynomial_calc(&poly_N_to_volt, data);
+
+	return 0;
+}
+
+static const struct hwmon_channel_info *pvt_channel_info[] = {
+	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_LABEL),
+	HWMON_CHANNEL_INFO(in, HWMON_I_INPUT | HWMON_I_LABEL),
+	NULL
+};
+
+static umode_t eic7700_pvt_hwmon_is_visible(const void *data,
+					    enum hwmon_sensor_types type,
+					    u32 attr, int ch)
+{
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+		case hwmon_temp_label:
+			return 0444;
+		}
+		break;
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_input:
+		case hwmon_in_label:
+			return 0444;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int eic7700_pvt_hwmon_read(struct device *dev,
+				  enum hwmon_sensor_types type, u32 attr,
+				  int ch, long *val)
+{
+	struct pvt_hwmon *pvt = dev_get_drvdata(dev);
+	int ret;
+
+	ret = pm_runtime_get_sync(pvt->dev);
+	if (ret < 0) {
+		dev_err(pvt->dev, "Failed to resume PVT device: %d\n", ret);
+		pm_runtime_put_noidle(pvt->dev);
+		return ret;
+	}
+
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			ret = eic7700_pvt_read_data(pvt, ch, val);
+			break;
+		default:
+			ret = -EOPNOTSUPP;
+		}
+		break;
+	case hwmon_in:
+		if (attr == hwmon_in_input)
+			ret = eic7700_pvt_read_data(pvt, PVT_VOLT + ch, val);
+		else
+			ret = -EOPNOTSUPP;
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+	}
+
+	pm_runtime_mark_last_busy(pvt->dev);
+	pm_runtime_put_autosuspend(pvt->dev);
+	return ret;
+}
+
+static int eic7700_pvt_hwmon_read_string(struct device *dev,
+					 enum hwmon_sensor_types type, u32 attr,
+					 int ch, const char **str)
+{
+	switch (type) {
+	case hwmon_temp:
+		if (attr == hwmon_temp_label) {
+			*str = pvt_info[ch].label;
+			return 0;
+		}
+		break;
+	case hwmon_in:
+		if (attr == hwmon_in_label) {
+			*str = pvt_info[PVT_VOLT + ch].label;
+			return 0;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static const struct hwmon_ops pvt_hwmon_ops = {
+	.is_visible = eic7700_pvt_hwmon_is_visible,
+	.read = eic7700_pvt_hwmon_read,
+	.read_string = eic7700_pvt_hwmon_read_string
+};
+
+static const struct hwmon_chip_info pvt_hwmon_info = {
+	.ops = &pvt_hwmon_ops,
+	.info = pvt_channel_info
+};
+
+static struct pvt_hwmon *eic7700_pvt_create_data(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct pvt_hwmon *pvt;
+
+	pvt = devm_kzalloc(dev, sizeof(*pvt), GFP_KERNEL);
+	if (!pvt)
+		return ERR_PTR(-ENOMEM);
+
+	pvt->dev = dev;
+	init_completion(&pvt->conversion);
+
+	return pvt;
+}
+
+static int eic7700_pvt_init_iface(struct pvt_hwmon *pvt)
+{
+	/*
+	 * Make sure controller are disabled so not to accidentally have ISR
+	 * executed before the driver data is fully initialized. Clear the IRQ
+	 * status as well.
+	 */
+	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, 0);
+	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);
+	readl(pvt->regs + PVT_INT);
+	readl(pvt->regs + PVT_DATA);
+
+	/* Setup default sensor mode and temperature trim. */
+	eic7700_pvt_set_mode(pvt, pvt_info[PVT_TEMP].mode);
+
+	/*
+	 * Max conversion latency (~333 µs) derived from PVT spec:
+	 * maximum sampling rate = 3000 samples/sec.
+	 */
+	pvt->timeout = ns_to_ktime(PVT_TOUT_MIN);
+
+	eic7700_pvt_set_trim(pvt, PVT_TRIM_DEF);
+
+	return 0;
+}
+
+static int eic7700_pvt_request_irq(struct pvt_hwmon *pvt)
+{
+	struct platform_device *pdev = to_platform_device(pvt->dev);
+	int ret;
+
+	pvt->irq = platform_get_irq(pdev, 0);
+	if (pvt->irq < 0)
+		return pvt->irq;
+
+	ret = devm_request_threaded_irq(pvt->dev, pvt->irq,
+					eic7700_pvt_hard_isr, NULL,
+					IRQF_TRIGGER_HIGH, "pvt", pvt);
+	if (ret) {
+		dev_err(pvt->dev, "Couldn't request PVT IRQ\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int eic7700_pvt_create_hwmon(struct pvt_hwmon *pvt)
+{
+	pvt->hwmon = devm_hwmon_device_register_with_info(pvt->dev, "pvt",
+							  pvt, &pvt_hwmon_info,
+							  NULL);
+	if (IS_ERR(pvt->hwmon)) {
+		dev_err(pvt->dev, "Couldn't create hwmon device\n");
+		return PTR_ERR(pvt->hwmon);
+	}
+
+	return 0;
+}
+
+static void eic7700_pvt_disable_pm_runtime(void *data)
+{
+	struct pvt_hwmon *pvt = data;
+
+	pm_runtime_dont_use_autosuspend(pvt->dev);
+	pm_runtime_disable(pvt->dev);
+
+	if (!pm_runtime_status_suspended(pvt->dev)) {
+		clk_disable_unprepare(pvt->clk);
+		pm_runtime_set_suspended(pvt->dev);
+	}
+}
+
+static int eic7700_pvt_probe(struct platform_device *pdev)
+{
+	struct reset_control *rst;
+	struct pvt_hwmon *pvt;
+	int ret;
+
+	pvt = eic7700_pvt_create_data(pdev);
+	if (IS_ERR(pvt))
+		return PTR_ERR(pvt);
+
+	platform_set_drvdata(pdev, pvt);
+
+	pvt->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(pvt->regs))
+		return PTR_ERR(pvt->regs);
+
+	pvt->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(pvt->clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(pvt->clk),
+				     "Couldn't get clock\n");
+
+	rst = devm_reset_control_get_exclusive_deasserted(&pdev->dev, NULL);
+	if (IS_ERR(rst))
+		return dev_err_probe(pvt->dev, PTR_ERR(rst),
+				     "Couldn't get reset control\n");
+
+	ret = clk_prepare_enable(pvt->clk);
+	if (ret)
+		return dev_err_probe(pvt->dev, ret, "Failed to enable clock\n");
+
+	ret = eic7700_pvt_init_iface(pvt);
+	if (ret) {
+		clk_disable_unprepare(pvt->clk);
+		return ret;
+	}
+
+	if (IS_ENABLED(CONFIG_PM))
+		clk_disable_unprepare(pvt->clk);
+
+	ret = eic7700_pvt_request_irq(pvt);
+	if (ret) {
+		if (!IS_ENABLED(CONFIG_PM))
+			clk_disable_unprepare(pvt->clk);
+		return ret;
+	}
+
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 3000);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_get_noresume(&pdev->dev);
+
+	ret = devm_add_action_or_reset(pvt->dev, eic7700_pvt_disable_pm_runtime,
+				       pvt);
+	if (ret) {
+		pm_runtime_put_noidle(&pdev->dev);
+		return dev_err_probe(&pdev->dev, ret,
+				     "Can't register PM cleanup\n");
+	}
+
+	ret = eic7700_pvt_create_hwmon(pvt);
+	if (ret)
+		goto err_put_pm_runtime;
+
+	pm_runtime_put_autosuspend(&pdev->dev);
+
+	return 0;
+
+err_put_pm_runtime:
+	pm_runtime_put_noidle(&pdev->dev);
+	return ret;
+}
+
+static int __maybe_unused eic7700_pvt_runtime_resume(struct device *dev)
+{
+	struct pvt_hwmon *pvt = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(pvt->clk);
+	if (ret) {
+		dev_err(dev, "Failed to enable clock: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __maybe_unused eic7700_pvt_runtime_suspend(struct device *dev)
+{
+	struct pvt_hwmon *pvt = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(pvt->clk);
+
+	return 0;
+}
+
+static const struct dev_pm_ops eic7700_pvt_pm_ops = {
+	SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
+	RUNTIME_PM_OPS(eic7700_pvt_runtime_suspend, eic7700_pvt_runtime_resume,
+		       NULL)
+};
+
+static const struct of_device_id pvt_of_match[] = {
+	{ .compatible = "eswin,eic7700-pvt"},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pvt_of_match);
+
+static struct platform_driver pvt_driver = {
+	.probe = eic7700_pvt_probe,
+	.driver = {
+		.name = "eic7700-pvt",
+		.of_match_table = pvt_of_match,
+		.pm = pm_ptr(&eic7700_pvt_pm_ops),
+	},
+};
+module_platform_driver(pvt_driver);
+
+MODULE_AUTHOR("Yulin Lu <luyulin@eswincomputing.com>");
+MODULE_AUTHOR("Huan He <hehuan1@eswincomputing.com>");
+MODULE_DESCRIPTION("Eswin eic7700 PVT driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hwmon/eic7700-pvt.h b/drivers/hwmon/eic7700-pvt.h
new file mode 100644
index 000000000000..b864326e8b4f
--- /dev/null
+++ b/drivers/hwmon/eic7700-pvt.h
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * ESWIN EIC7700 Voltage, Temperature sensor driver
+ *
+ * Copyright 2026, Beijing ESWIN Computing Technology Co., Ltd.
+ */
+#ifndef __HWMON_EIC7700_PVT_H__
+#define __HWMON_EIC7700_PVT_H__
+
+#include <linux/completion.h>
+#include <linux/hwmon.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+
+/* ESWIN EIC7700 PVT registers and their bitfields */
+#define PVT_TRIM		0x04
+#define PVT_MODE		0x08
+#define PVT_MODE_MASK		GENMASK(2, 0)
+#define PVT_CTRL_MODE_TEMP	0x0
+#define PVT_CTRL_MODE_VOLT	0x4
+#define PVT_ENA			0x0c
+#define PVT_ENA_EN		BIT(0)
+#define PVT_INT			0x10
+#define PVT_INT_STAT		BIT(0)
+#define PVT_INT_CLR		BIT(1)
+#define PVT_DATA		0x14
+#define PVT_DATA_OUT		GENMASK(9, 0)
+
+/*
+ * PVT sensors-related limits and default values
+ * @PVT_TEMP_CHS: Number of temperature hwmon channels.
+ * @PVT_VOLT_CHS: Number of voltage hwmon channels.
+ * @PVT_TRIM_DEF: Default temperature sensor trim value (set a proper value
+ *		  when one is determined for ESWIN EIC7700 SoC).
+ * @PVT_TOUT_MIN: Minimal timeout between samples in nanoseconds.
+ */
+#define PVT_TEMP_CHS		1
+#define PVT_VOLT_CHS		1
+#define PVT_TRIM_DEF		0
+#define PVT_TOUT_MIN		(NSEC_PER_SEC / 3000)
+
+/*
+ * enum pvt_sensor_type - ESWIN EIC7700 PVT sensor types (correspond to each PVT
+ *			  sampling mode)
+ * @PVT_TEMP: PVT Temperature sensor.
+ * @PVT_VOLT: PVT Voltage sensor.
+ */
+enum pvt_sensor_type {
+	PVT_TEMP = 0,
+	PVT_VOLT
+};
+
+/*
+ * struct pvt_sensor_info - ESWIN EIC7700 PVT sensor informational structure
+ * @channel: Sensor channel ID.
+ * @label: hwmon sensor label.
+ * @mode: PVT mode corresponding to the channel.
+ * @type: Sensor type.
+ */
+struct pvt_sensor_info {
+	int channel;
+	const char *label;
+	u32 mode;
+	enum hwmon_sensor_types type;
+};
+
+#define PVT_SENSOR_INFO(_ch, _label, _type, _mode)	\
+	{						\
+		.channel = _ch,				\
+		.label = _label,			\
+		.mode = PVT_CTRL_MODE_ ##_mode,		\
+		.type = _type,				\
+	}
+
+/*
+ * struct pvt_hwmon - Eswin EIC7700 PVT private data
+ * @dev: device structure of the PVT platform device.
+ * @hwmon: hwmon device structure.
+ * @regs: pointer to the Eswin EIC7700 PVT registers region.
+ * @irq: PVT events IRQ number.
+ * @clk: PVT core clock (1.2MHz).
+ * @rst: pointer to the reset descriptor.
+ * @data_cache: data cache in raw format.
+ * @conversion: data conversion completion.
+ * @timeout: conversion timeout.
+ */
+struct pvt_hwmon {
+	struct device *dev;
+	struct device *hwmon;
+	void __iomem *regs;
+	int irq;
+	struct clk *clk;
+	u32 data_cache;
+	struct completion conversion;
+	ktime_t timeout;
+};
+
+#endif /* __HWMON_EIC7700_PVT_H__ */
-- 
2.25.1

Re: [PATCH v7 1/2] dt-bindings: hwmon: Add Eswin EIC7700 PVT sensor

[sashiko-bot]

> From: Huan He <hehuan1@eswincomputing.com>
> 
> Add device tree binding documentation for ESWIN EIC7700 Voltage and
> Temperature sensor.
> 
> The EIC7700 SoC integrates two PVT instances for monitoring SoC and DDR
> power domains respectively.
> 
> Signed-off-by: Yulin Lu <luyulin@eswincomputing.com>
> Signed-off-by: Huan He <hehuan1@eswincomputing.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260611090505.734-1-hehuan1@eswincomputing.com?part=1

Re: [PATCH v7 2/2] hwmon: Add Eswin EIC7700 PVT sensor driver

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] The IRQ is requested before the PM runtime cleanup action is registered, leading to a possible use-after-disable of the hardware clock in the ISR on driver removal.
- [Medium] The interrupt handler `eic7700_pvt_hard_isr` does not check the hardware interrupt status bit to verify if the device actually generated the interrupt.
--

commit 0f4c8aefb83780ee09652639eb2843f01c2baf38
Author: Huan He <hehuan1@eswincomputing.com>

hwmon: Add Eswin EIC7700 PVT sensor driver

Add support for ESWIN EIC7700 Voltage and Temperature sensor. The driver
supports temperature and voltage monitoring with polynomial conversion,
and provides sysfs interface for sensor data access.

> diff --git a/drivers/hwmon/eic7700-pvt.c b/drivers/hwmon/eic7700-pvt.c
> new file mode 100644
> index 0000000000000..3b3aed74c3941
> --- /dev/null
> +++ b/drivers/hwmon/eic7700-pvt.c

[ ... ]

> +static irqreturn_t eic7700_pvt_hard_isr(int irq, void *data)
> +{
> +	struct pvt_hwmon *pvt = data;
> +	int active;
> +	u32 val;
> +
> +	if (IS_ENABLED(CONFIG_PM)) {
> +		active = pm_runtime_get_if_active(pvt->dev);
> +		if (active <= 0)
> +			return IRQ_NONE;
> +	}
> +
> +	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);
> +	/*
> +	 * Read the data, update the cache and notify a waiter of this event.
> +	 */
> +	val = readl(pvt->regs + PVT_DATA);
> +	WRITE_ONCE(pvt->data_cache, FIELD_GET(PVT_DATA_OUT, val));
> +	complete(&pvt->conversion);

[Severity: Medium]
Does this unconditionally process the interrupt without checking if the device
actually generated it?

If a spurious interrupt occurs, the ISR will prematurely clear the interrupt,
read whatever stale value is in PVT_DATA, and call complete(&pvt->conversion).
This will cause the waiting thread in eic7700_pvt_read_data() to wake up early
and return stale or garbage data to userspace.

Should the ISR read the status register and return IRQ_NONE if its device did
not assert the interrupt?

[ ... ]

> +	ret = eic7700_pvt_request_irq(pvt);
> +	if (ret) {
> +		if (!IS_ENABLED(CONFIG_PM))
> +			clk_disable_unprepare(pvt->clk);
> +		return ret;
> +	}
> +
> +	pm_runtime_enable(&pdev->dev);
> +	pm_runtime_set_autosuspend_delay(&pdev->dev, 3000);
> +	pm_runtime_use_autosuspend(&pdev->dev);
> +	pm_runtime_get_noresume(&pdev->dev);
> +
> +	ret = devm_add_action_or_reset(pvt->dev, eic7700_pvt_disable_pm_runtime,
> +				       pvt);

[Severity: High]
Can this devres setup lead to accessing unclocked registers during device
removal?

Because devres executes teardown callbacks in reverse order of their
registration, eic7700_pvt_disable_pm_runtime() will run before the IRQ
is freed by devm_request_threaded_irq()'s teardown.

During removal, eic7700_pvt_disable_pm_runtime() disables the clock:

eic7700_pvt_disable_pm_runtime() {
    ...
    if (!pm_runtime_status_suspended(pvt->dev)) {
        clk_disable_unprepare(pvt->clk);
        pm_runtime_set_suspended(pvt->dev);
    }
}

If an interrupt fires concurrently and the ISR executes past the
pm_runtime_get_if_active() check before the clock is disabled, the ISR
will attempt to access hardware registers while unclocked, which can lead
to an external abort or kernel panic:

eic7700_pvt_hard_isr() {
    ...
    eic7700_pvt_update(pvt->regs + PVT_INT, ...);
}

Should the PM runtime cleanup action be registered before the IRQ is requested?

> +	if (ret) {
> +		pm_runtime_put_noidle(&pdev->dev);
> +		return dev_err_probe(&pdev->dev, ret,
> +				     "Can't register PM cleanup\n");
> +	}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260611090505.734-1-hehuan1@eswincomputing.com?part=2