[PATCH v3 0/2] Add driver support for ESWIN EIC7700 PVT controller

[PATCH v3 0/2] Add driver support for ESWIN EIC7700 PVT controller

[hehuan1]

From: Huan He <hehuan1@eswincomputing.com>

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

Features:
The driver supports monitoring of process, 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 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     |  65 ++
 drivers/hwmon/Kconfig                         |  12 +
 drivers/hwmon/Makefile                        |   1 +
 drivers/hwmon/eic7700-pvt.c                   | 634 ++++++++++++++++++
 drivers/hwmon/eic7700-pvt.h                   | 108 +++
 5 files changed, 820 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 v3 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 Process, 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: Conor Dooley <conor.dooley@microchip.com>
---
 .../bindings/hwmon/eswin,eic7700-pvt.yaml     | 65 +++++++++++++++++++
 1 file changed, 65 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..366dce3c6d43
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/eswin,eic7700-pvt.yaml
@@ -0,0 +1,65 @@
+# 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 process, 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
+
+  label: true
+
+  resets:
+    maxItems: 1
+
+  '#thermal-sensor-cells':
+    const: 0
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - interrupts
+  - label
+  - resets
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    pvt@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 v3 2/2] hwmon: Add Eswin EIC7700 PVT sensor driver

[hehuan1]

From: Huan He <hehuan1@eswincomputing.com>

Add support for ESWIN EIC7700 Process, 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 four voltage sensors for
process variation monitoring.

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 | 634 ++++++++++++++++++++++++++++++++++++
 drivers/hwmon/eic7700-pvt.h | 108 ++++++
 4 files changed, 755 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 41c381764c2b..d2dbf70f04c1 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2043,6 +2043,18 @@ 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 Process, 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 eade8e3b1bde..1b2845bd5a54 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -72,6 +72,7 @@ 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..c4ac4f504080
--- /dev/null
+++ b/drivers/hwmon/eic7700-pvt.c
@@ -0,0 +1,634 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ESWIN EIC7700 Process, 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),
+	PVT_SENSOR_INFO(1, "Low-Vt", hwmon_in, LVT),
+	PVT_SENSOR_INFO(2, "UltraLow-Vt", hwmon_in, ULVT),
+	PVT_SENSOR_INFO(3, "Standard-Vt", hwmon_in, SVT),
+};
+
+/*
+ * 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;
+	u32 val;
+
+	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);
+
+	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);
+
+	data = READ_ONCE(pvt->data_cache);
+
+	if (!ret)
+		return -ETIMEDOUT;
+
+	if (type == PVT_TEMP)
+		*val = polynomial_calc(&poly_N_to_temp, data);
+	else if (type == PVT_VOLT)
+		*val = polynomial_calc(&poly_N_to_volt, data);
+	else
+		*val = 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_T_OFFSET),
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   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;
+		case hwmon_temp_offset:
+			return 0644;
+		}
+		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_read_trim(struct pvt_hwmon *pvt, long *val)
+{
+	u32 data;
+
+	data = readl(pvt->regs + PVT_TRIM);
+	*val = data;
+
+	return 0;
+}
+
+static int eic7700_pvt_write_trim(struct pvt_hwmon *pvt, long val)
+{
+	/*
+	 * Update PVT trim register safely while the controller is temporarily
+	 * disabled.
+	 */
+	eic7700_pvt_set_trim(pvt, val);
+
+	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);
+		return ret;
+	}
+
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			ret = eic7700_pvt_read_data(pvt, ch, val);
+			break;
+		case hwmon_temp_offset:
+			ret = eic7700_pvt_read_trim(pvt, 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 int eic7700_pvt_hwmon_write(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);
+		return ret;
+	}
+
+	if (type == hwmon_temp && attr == hwmon_temp_offset)
+		ret = eic7700_pvt_write_trim(pvt, val);
+	else
+		ret = -EOPNOTSUPP;
+
+	pm_runtime_mark_last_busy(pvt->dev);
+	pm_runtime_put_autosuspend(pvt->dev);
+	return ret;
+}
+
+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,
+	.write = eic7700_pvt_hwmon_write
+};
+
+static const struct hwmon_chip_info pvt_hwmon_info = {
+	.ops = &pvt_hwmon_ops,
+	.info = pvt_channel_info
+};
+
+static void pvt_clear_data(void *data)
+{
+	struct pvt_hwmon *pvt = data;
+
+	complete_all(&pvt->conversion);
+}
+
+static struct pvt_hwmon *eic7700_pvt_create_data(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct pvt_hwmon *pvt;
+	int ret;
+
+	pvt = devm_kzalloc(dev, sizeof(*pvt), GFP_KERNEL);
+	if (!pvt)
+		return ERR_PTR(-ENOMEM);
+
+	pvt->dev = dev;
+	init_completion(&pvt->conversion);
+
+	ret = devm_add_action(dev, pvt_clear_data, pvt);
+	if (ret) {
+		dev_err(dev, "Can't add PVT data clear action\n");
+		return ERR_PTR(ret);
+	}
+
+	return pvt;
+}
+
+static int eic7700_pvt_check_pwr(struct pvt_hwmon *pvt)
+{
+	unsigned long tout;
+	int ret = 0;
+
+	/*
+	 * Test out the sensor conversion functionality. If it is not done on
+	 * time then the domain must have been unpowered and we won't be able
+	 * to use the device later in this driver.
+	 */
+	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);
+	/*
+	 * Enable the PVT block to test if the sensor domain is powered.
+	 *
+	 * This happens before request_irq(). Enabling the block may generate
+	 * an interrupt on shared IRQ lines before a handler is registered.
+	 *
+	 * The hardware does not provide a dedicated interrupt enable bit in
+	 * PVT_ENA and PVT_INT does not support interrupt masking. After the
+	 * test, the driver disables the PVT block and clears the interrupt
+	 * status via PVT_INT_CLR, preventing stale interrupts.
+	 */
+	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, PVT_ENA_EN);
+	readl(pvt->regs + PVT_DATA);
+
+	tout = PVT_TOUT_MIN / NSEC_PER_USEC;
+	usleep_range(tout, 2 * tout);
+
+	readl(pvt->regs + PVT_DATA);
+	if (!(readl(pvt->regs + PVT_INT) & PVT_INT_STAT)) {
+		ret = -ENODEV;
+		dev_err(pvt->dev,
+			"Sensor is powered down - no interrupt generated\n");
+	}
+
+	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, 0);
+	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);
+
+	return ret;
+}
+
+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_INT, PVT_INT_CLR, PVT_INT_CLR);
+	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, 0);
+	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_SHARED | 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)
+{
+	struct device *dev = pvt->dev;
+	struct device_node *np = dev->of_node;
+	const char *node_label;
+	int type;
+	const char *names[2] = {"soc_pvt", "ddr_pvt"};
+
+	if (of_property_read_string(np, "label", &node_label)) {
+		dev_err(dev, "Missing 'label' property in DTS node\n");
+		return -EINVAL;
+	}
+
+	if (strcmp(node_label, "pvt0") == 0) {
+		type = 0;
+	} else if (strcmp(node_label, "pvt1") == 0) {
+		type = 1;
+	} else {
+		dev_err(pvt->dev, "Unsupported label: %s\n", node_label);
+		return -EINVAL;
+	}
+
+	pvt->hwmon = devm_hwmon_device_register_with_info(pvt->dev, names[type],
+							  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);
+}
+
+static int eic7700_pvt_probe(struct platform_device *pdev)
+{
+	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");
+
+	pvt->rst = devm_reset_control_get_exclusive_deasserted(&pdev->dev,
+							       NULL);
+	if (IS_ERR(pvt->rst))
+		return dev_err_probe(pvt->dev, PTR_ERR(pvt->rst),
+				     "Couldn't get reset control\n");
+
+	clk_prepare_enable(pvt->clk);
+
+	ret = eic7700_pvt_check_pwr(pvt);
+	if (ret)
+		return ret;
+
+	clk_disable_unprepare(pvt->clk);
+
+	ret = eic7700_pvt_init_iface(pvt);
+	if (ret)
+		return ret;
+
+	ret = eic7700_pvt_request_irq(pvt);
+	if (ret)
+		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)
+		return dev_err_probe(&pdev->dev, ret,
+				     "Can't register PM cleanup\n");
+
+	ret = eic7700_pvt_create_hwmon(pvt);
+	if (ret)
+		return ret;
+
+	pm_runtime_put_autosuspend(&pdev->dev);
+
+	return 0;
+}
+
+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 int __maybe_unused eic7700_pvt_suspend(struct device *dev)
+{
+	int ret = 0;
+
+	if (!pm_runtime_status_suspended(dev)) {
+		ret = eic7700_pvt_runtime_suspend(dev);
+		if (ret) {
+			dev_err(dev, "Failed to suspend: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int __maybe_unused eic7700_pvt_resume(struct device *dev)
+{
+	int ret = 0;
+
+	if (!pm_runtime_status_suspended(dev)) {
+		ret = eic7700_pvt_runtime_resume(dev);
+		if (ret) {
+			dev_err(dev, "Failed to resume: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static const struct dev_pm_ops eic7700_pvt_pm_ops = {
+	SYSTEM_SLEEP_PM_OPS(eic7700_pvt_suspend, eic7700_pvt_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_sleep_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..1e4cb27e4254
--- /dev/null
+++ b/drivers/hwmon/eic7700-pvt.h
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * ESWIN EIC7700 Process, 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_CTRL_MODE_LVT	0x1
+#define PVT_CTRL_MODE_ULVT	0x2
+#define PVT_CTRL_MODE_SVT	0x3
+#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		4
+#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.
+ * @PVT_LVT: PVT Low-Voltage threshold sensor.
+ * @PVT_ULVT: PVT UltraLow-Voltage threshold sensor.
+ * @PVT_SVT: PVT Standard-Voltage threshold sensor.
+ */
+enum pvt_sensor_type {
+	PVT_TEMP = 0,
+	PVT_VOLT,
+	PVT_LVT,
+	PVT_ULVT,
+	PVT_SVT
+};
+
+/*
+ * 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;
+	struct reset_control *rst;
+	u32 data_cache;
+	struct completion conversion;
+	ktime_t timeout;
+};
+
+#endif /* __HWMON_EIC7700_PVT_H__ */
-- 
2.25.1

Re: [PATCH v3 2/2] hwmon: Add Eswin EIC7700 PVT sensor driver

[Guenter Roeck]

On Fri, Mar 06, 2026 at 05:47:18PM +0800, hehuan1@eswincomputing.com wrote:
> From: Huan He <hehuan1@eswincomputing.com>
> 
> Add support for ESWIN EIC7700 Process, 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 four voltage sensors for
> process variation monitoring.
> 
> Signed-off-by: Yulin Lu <luyulin@eswincomputing.com>
> Signed-off-by: Huan He <hehuan1@eswincomputing.com>

Feedback from AI review inline.

> ---
>  drivers/hwmon/Kconfig       |  12 +
>  drivers/hwmon/Makefile      |   1 +
>  drivers/hwmon/eic7700-pvt.c | 634 ++++++++++++++++++++++++++++++++++++
>  drivers/hwmon/eic7700-pvt.h | 108 ++++++
>  4 files changed, 755 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 41c381764c2b..d2dbf70f04c1 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -2043,6 +2043,18 @@ 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 Process, 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 eade8e3b1bde..1b2845bd5a54 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -72,6 +72,7 @@ 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..c4ac4f504080
> --- /dev/null
> +++ b/drivers/hwmon/eic7700-pvt.c
> @@ -0,0 +1,634 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ESWIN EIC7700 Process, 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),
> +	PVT_SENSOR_INFO(1, "Low-Vt", hwmon_in, LVT),
> +	PVT_SENSOR_INFO(2, "UltraLow-Vt", hwmon_in, ULVT),
> +	PVT_SENSOR_INFO(3, "Standard-Vt", hwmon_in, SVT),

[not from AI]

Are those limits reported as voltages ? If so, that would violate the ABI.

> +};
> +
> +/*
> + * 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;
> +	u32 val;
> +
> +	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);

Since the IRQ is registered with IRQF_SHARED, it can be triggered by other
devices while this PVT sensor is runtime suspended and its clock is disabled.
Will accessing pvt->regs here cause a bus fault?

Should the handler use pm_runtime_get_if_active() to verify the device is
powered before touching its registers?

Additionally, the handler does not verify if the interrupt originated from
this device before clearing it. Should it check PVT_INT_STAT and return
IRQ_NONE if the interrupt is not ours?

> +	/*
> +	 * 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);
> +
> +	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);
> +
> +	data = READ_ONCE(pvt->data_cache);
> +
> +	if (!ret)
> +		return -ETIMEDOUT;
> +
> +	if (type == PVT_TEMP)
> +		*val = polynomial_calc(&poly_N_to_temp, data);
> +	else if (type == PVT_VOLT)
> +		*val = polynomial_calc(&poly_N_to_volt, data);
> +	else
> +		*val = data;

For PVT_LVT, PVT_ULVT, and PVT_SVT (which are exported as hwmon_in channels),
this returns the raw data. Does this violate the hwmon ABI, which requires
voltage readings to be in millivolts? Should poly_N_to_volt be applied to all
voltage channels?

> +
> +	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_T_OFFSET),
> +	HWMON_CHANNEL_INFO(in,
> +			   HWMON_I_INPUT | HWMON_I_LABEL,
> +			   HWMON_I_INPUT | HWMON_I_LABEL,
> +			   HWMON_I_INPUT | HWMON_I_LABEL,
> +			   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;
> +		case hwmon_temp_offset:
> +			return 0644;
> +		}
> +		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_read_trim(struct pvt_hwmon *pvt, long *val)
> +{
> +	u32 data;
> +
> +	data = readl(pvt->regs + PVT_TRIM);
> +	*val = data;
> +
> +	return 0;
> +}
> +
> +static int eic7700_pvt_write_trim(struct pvt_hwmon *pvt, long val)
> +{
> +	/*
> +	 * Update PVT trim register safely while the controller is temporarily
> +	 * disabled.
> +	 */
> +	eic7700_pvt_set_trim(pvt, val);
> +
> +	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);
> +		return ret;
> +	}
> +
> +	switch (type) {
> +	case hwmon_temp:
> +		switch (attr) {
> +		case hwmon_temp_input:
> +			ret = eic7700_pvt_read_data(pvt, ch, val);
> +			break;
> +		case hwmon_temp_offset:
> +			ret = eic7700_pvt_read_trim(pvt, 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 int eic7700_pvt_hwmon_write(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);
> +		return ret;
> +	}
> +
> +	if (type == hwmon_temp && attr == hwmon_temp_offset)
> +		ret = eic7700_pvt_write_trim(pvt, val);
> +	else
> +		ret = -EOPNOTSUPP;
> +
> +	pm_runtime_mark_last_busy(pvt->dev);
> +	pm_runtime_put_autosuspend(pvt->dev);
> +	return ret;
> +}
> +
> +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,
> +	.write = eic7700_pvt_hwmon_write
> +};
> +
> +static const struct hwmon_chip_info pvt_hwmon_info = {
> +	.ops = &pvt_hwmon_ops,
> +	.info = pvt_channel_info
> +};
> +
> +static void pvt_clear_data(void *data)
> +{
> +	struct pvt_hwmon *pvt = data;
> +
> +	complete_all(&pvt->conversion);
> +}
> +
> +static struct pvt_hwmon *eic7700_pvt_create_data(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct pvt_hwmon *pvt;
> +	int ret;
> +
> +	pvt = devm_kzalloc(dev, sizeof(*pvt), GFP_KERNEL);
> +	if (!pvt)
> +		return ERR_PTR(-ENOMEM);
> +
> +	pvt->dev = dev;
> +	init_completion(&pvt->conversion);
> +
> +	ret = devm_add_action(dev, pvt_clear_data, pvt);
> +	if (ret) {
> +		dev_err(dev, "Can't add PVT data clear action\n");
> +		return ERR_PTR(ret);
> +	}
> +
> +	return pvt;
> +}
> +
> +static int eic7700_pvt_check_pwr(struct pvt_hwmon *pvt)
> +{
> +	unsigned long tout;
> +	int ret = 0;
> +
> +	/*
> +	 * Test out the sensor conversion functionality. If it is not done on
> +	 * time then the domain must have been unpowered and we won't be able
> +	 * to use the device later in this driver.
> +	 */
> +	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);
> +	/*
> +	 * Enable the PVT block to test if the sensor domain is powered.
> +	 *
> +	 * This happens before request_irq(). Enabling the block may generate
> +	 * an interrupt on shared IRQ lines before a handler is registered.
> +	 *
> +	 * The hardware does not provide a dedicated interrupt enable bit in
> +	 * PVT_ENA and PVT_INT does not support interrupt masking. After the
> +	 * test, the driver disables the PVT block and clears the interrupt
> +	 * status via PVT_INT_CLR, preventing stale interrupts.
> +	 */
> +	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, PVT_ENA_EN);
> +	readl(pvt->regs + PVT_DATA);
> +
> +	tout = PVT_TOUT_MIN / NSEC_PER_USEC;
> +	usleep_range(tout, 2 * tout);

Since this IRQ is shared and level-triggered, won't generating an interrupt
before the handler is registered cause an IRQ storm? The interrupt controller
will fire continuously during the usleep_range(), which could cause the
kernel's spurious IRQ detector to permanently disable the shared IRQ line.

> +
> +	readl(pvt->regs + PVT_DATA);
> +	if (!(readl(pvt->regs + PVT_INT) & PVT_INT_STAT)) {
> +		ret = -ENODEV;
> +		dev_err(pvt->dev,
> +			"Sensor is powered down - no interrupt generated\n");
> +	}
> +
> +	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, 0);
> +	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);
> +
> +	return ret;
> +}
> +
> +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_INT, PVT_INT_CLR, PVT_INT_CLR);
> +	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, 0);
> +	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_SHARED | 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)
> +{
> +	struct device *dev = pvt->dev;
> +	struct device_node *np = dev->of_node;
> +	const char *node_label;
> +	int type;
> +	const char *names[2] = {"soc_pvt", "ddr_pvt"};
> +
> +	if (of_property_read_string(np, "label", &node_label)) {
> +		dev_err(dev, "Missing 'label' property in DTS node\n");
> +		return -EINVAL;
> +	}
> +
> +	if (strcmp(node_label, "pvt0") == 0) {
> +		type = 0;
> +	} else if (strcmp(node_label, "pvt1") == 0) {
> +		type = 1;
> +	} else {
> +		dev_err(pvt->dev, "Unsupported label: %s\n", node_label);
> +		return -EINVAL;
> +	}
> +
> +	pvt->hwmon = devm_hwmon_device_register_with_info(pvt->dev, names[type],
> +							  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);
> +}
> +
> +static int eic7700_pvt_probe(struct platform_device *pdev)
> +{
> +	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");
> +
> +	pvt->rst = devm_reset_control_get_exclusive_deasserted(&pdev->dev,
> +							       NULL);
> +	if (IS_ERR(pvt->rst))
> +		return dev_err_probe(pvt->dev, PTR_ERR(pvt->rst),
> +				     "Couldn't get reset control\n");
> +
> +	clk_prepare_enable(pvt->clk);
> +
> +	ret = eic7700_pvt_check_pwr(pvt);
> +	if (ret)
> +		return ret;
> +
> +	clk_disable_unprepare(pvt->clk);
> +
> +	ret = eic7700_pvt_init_iface(pvt);
> +	if (ret)
> +		return ret;

In eic7700_pvt_init_iface(pvt), the code accesses the device's registers.
Since clk_disable_unprepare(pvt->clk) is called right before it, won't
accessing the hardware registers here cause a bus fault? Should the clock be
disabled after initialization instead?

> +
> +	ret = eic7700_pvt_request_irq(pvt);
> +	if (ret)
> +		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)
> +		return dev_err_probe(&pdev->dev, ret,
> +				     "Can't register PM cleanup\n");
> +
> +	ret = eic7700_pvt_create_hwmon(pvt);
> +	if (ret)
> +		return ret;

If eic7700_pvt_create_hwmon() fails, the function returns early. The devres
action disables runtime PM, but it doesn't balance the
pm_runtime_get_noresume(). Does this leak the usage counter on probe failure?

> +
> +	pm_runtime_put_autosuspend(&pdev->dev);
> +
> +	return 0;
> +}
> +
> +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);
> +
Does this need a synchronize_irq(pvt->irq) before disabling the clock? Since
the IRQ is shared, a handler might be executing mid-flight on another CPU
when the clock is disabled, which could cause a bus fault.

> +	return 0;
> +}
> +
> +static int __maybe_unused eic7700_pvt_suspend(struct device *dev)
> +{
> +	int ret = 0;
> +
> +	if (!pm_runtime_status_suspended(dev)) {
> +		ret = eic7700_pvt_runtime_suspend(dev);
> +		if (ret) {
> +			dev_err(dev, "Failed to suspend: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused eic7700_pvt_resume(struct device *dev)
> +{
> +	int ret = 0;
> +
> +	if (!pm_runtime_status_suspended(dev)) {
> +		ret = eic7700_pvt_runtime_resume(dev);
> +		if (ret) {
> +			dev_err(dev, "Failed to resume: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops eic7700_pvt_pm_ops = {
> +	SYSTEM_SLEEP_PM_OPS(eic7700_pvt_suspend, eic7700_pvt_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_sleep_ptr(&eic7700_pvt_pm_ops),

Since eic7700_pvt_pm_ops contains runtime PM callbacks, using pm_sleep_ptr()
will drop the entire structure if CONFIG_PM_SLEEP is disabled but CONFIG_PM
is enabled. Should this use pm_ptr() instead?

> +	},
> +};
> +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..1e4cb27e4254
> --- /dev/null
> +++ b/drivers/hwmon/eic7700-pvt.h
> @@ -0,0 +1,108 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * ESWIN EIC7700 Process, 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_CTRL_MODE_LVT	0x1
> +#define PVT_CTRL_MODE_ULVT	0x2
> +#define PVT_CTRL_MODE_SVT	0x3
> +#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		4
> +#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.
> + * @PVT_LVT: PVT Low-Voltage threshold sensor.
> + * @PVT_ULVT: PVT UltraLow-Voltage threshold sensor.
> + * @PVT_SVT: PVT Standard-Voltage threshold sensor.
> + */
> +enum pvt_sensor_type {
> +	PVT_TEMP = 0,
> +	PVT_VOLT,
> +	PVT_LVT,
> +	PVT_ULVT,
> +	PVT_SVT
> +};
> +
> +/*
> + * 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;
> +	struct reset_control *rst;
> +	u32 data_cache;
> +	struct completion conversion;
> +	ktime_t timeout;
> +};
> +
> +#endif /* __HWMON_EIC7700_PVT_H__ */
> -- 
> 2.25.1
> 
> 

Re: Re: [PATCH v3 2/2] hwmon: Add Eswin EIC7700 PVT sensor driver

[Huan He]

Hi Guenter,

Thank you very much for your detailed review. We appreciate the feedback.

> > Add support for ESWIN EIC7700 Process, 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 four voltage sensors for
> > process variation monitoring.
> > 
> > Signed-off-by: Yulin Lu <luyulin@eswincomputing.com>
> > Signed-off-by: Huan He <hehuan1@eswincomputing.com>
> 
> Feedback from AI review inline.
> 
> > +#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),
> > +	PVT_SENSOR_INFO(1, "Low-Vt", hwmon_in, LVT),
> > +	PVT_SENSOR_INFO(2, "UltraLow-Vt", hwmon_in, ULVT),
> > +	PVT_SENSOR_INFO(3, "Standard-Vt", hwmon_in, SVT),
> 
> [not from AI]
> 
> Are those limits reported as voltages ? If so, that would violate the ABI.

According to the PVT datasheet, in process mode, the DATA_OUT values for
LVT, ULVT, and SVT are not voltages. They represent a combined effect of
process, voltage, temperature, and device type, and must be interpreted
using the corresponding lookup tables in the datasheet.
Exposing them as hwmon_in (voltage channels) violates the hwmon ABI. These
three channels are planned to be removed in the v4 release.

> 
> > +};
> > +
> > +/*
> > + * 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;
> > +	u32 val;
> > +
> > +	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);
> 
> Since the IRQ is registered with IRQF_SHARED, it can be triggered by other
> devices while this PVT sensor is runtime suspended and its clock is disabled.
> Will accessing pvt->regs here cause a bus fault?
> 
> Should the handler use pm_runtime_get_if_active() to verify the device is
> powered before touching its registers?
> 
> Additionally, the handler does not verify if the interrupt originated from
> this device before clearing it. Should it check PVT_INT_STAT and return
> IRQ_NONE if the interrupt is not ours?

It has been confirmed that the PVT interrupt is not shared. In the v4
patch, the driver will remove the use of IRQF_SHARED.
Since the interrupt is dedicated to the PVT sensor, there is no need to
use pm_runtime_get_if_active() to check whether the device is powered, nor
to verify PVT_INT_STAT to determine if the interrupt originated from this
device.

> 
> > +	/*
> > +	 * 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);
> > +
> > +	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);
> > +
> > +	data = READ_ONCE(pvt->data_cache);
> > +
> > +	if (!ret)
> > +		return -ETIMEDOUT;
> > +
> > +	if (type == PVT_TEMP)
> > +		*val = polynomial_calc(&poly_N_to_temp, data);
> > +	else if (type == PVT_VOLT)
> > +		*val = polynomial_calc(&poly_N_to_volt, data);
> > +	else
> > +		*val = data;
> 
> For PVT_LVT, PVT_ULVT, and PVT_SVT (which are exported as hwmon_in channels),
> this returns the raw data. Does this violate the hwmon ABI, which requires
> voltage readings to be in millivolts? Should poly_N_to_volt be applied to all
> voltage channels?

Exposing them as hwmon_in (voltage channels) violates the hwmon ABI. These
three channels are planned to be removed in the v4 release.

> 
> > +
> > +	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_T_OFFSET),
> > +	HWMON_CHANNEL_INFO(in,
> > +			   HWMON_I_INPUT | HWMON_I_LABEL,
> > +			   HWMON_I_INPUT | HWMON_I_LABEL,
> > +			   HWMON_I_INPUT | HWMON_I_LABEL,
> > +			   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;
> > +		case hwmon_temp_offset:
> > +			return 0644;
> > +		}
> > +		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);
> > +		return ret;
> > +	}
> > +
> > +	switch (type) {
> > +	case hwmon_temp:
> > +		switch (attr) {
> > +		case hwmon_temp_input:
> > +			ret = eic7700_pvt_read_data(pvt, ch, val);
> > +			break;
> > +		case hwmon_temp_offset:
> > +			ret = eic7700_pvt_read_trim(pvt, 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 int eic7700_pvt_hwmon_write(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);
> > +		return ret;
> > +	}
> > +
> > +	if (type == hwmon_temp && attr == hwmon_temp_offset)
> > +		ret = eic7700_pvt_write_trim(pvt, val);
> > +	else
> > +		ret = -EOPNOTSUPP;
> > +
> > +	pm_runtime_mark_last_busy(pvt->dev);
> > +	pm_runtime_put_autosuspend(pvt->dev);
> > +	return ret;
> > +}
> > +
> > +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,
> > +	.write = eic7700_pvt_hwmon_write
> > +};
> > +
> > +static const struct hwmon_chip_info pvt_hwmon_info = {
> > +	.ops = &pvt_hwmon_ops,
> > +	.info = pvt_channel_info
> > +};
> > +
> > +static void pvt_clear_data(void *data)
> > +{
> > +	struct pvt_hwmon *pvt = data;
> > +
> > +	complete_all(&pvt->conversion);
> > +}
> > +
> > +static struct pvt_hwmon *eic7700_pvt_create_data(struct platform_device *pdev)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct pvt_hwmon *pvt;
> > +	int ret;
> > +
> > +	pvt = devm_kzalloc(dev, sizeof(*pvt), GFP_KERNEL);
> > +	if (!pvt)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	pvt->dev = dev;
> > +	init_completion(&pvt->conversion);
> > +
> > +	ret = devm_add_action(dev, pvt_clear_data, pvt);
> > +	if (ret) {
> > +		dev_err(dev, "Can't add PVT data clear action\n");
> > +		return ERR_PTR(ret);
> > +	}
> > +
> > +	return pvt;
> > +}
> > +
> > +static int eic7700_pvt_check_pwr(struct pvt_hwmon *pvt)
> > +{
> > +	unsigned long tout;
> > +	int ret = 0;
> > +
> > +	/*
> > +	 * Test out the sensor conversion functionality. If it is not done on
> > +	 * time then the domain must have been unpowered and we won't be able
> > +	 * to use the device later in this driver.
> > +	 */
> > +	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);
> > +	/*
> > +	 * Enable the PVT block to test if the sensor domain is powered.
> > +	 *
> > +	 * This happens before request_irq(). Enabling the block may generate
> > +	 * an interrupt on shared IRQ lines before a handler is registered.
> > +	 *
> > +	 * The hardware does not provide a dedicated interrupt enable bit in
> > +	 * PVT_ENA and PVT_INT does not support interrupt masking. After the
> > +	 * test, the driver disables the PVT block and clears the interrupt
> > +	 * status via PVT_INT_CLR, preventing stale interrupts.
> > +	 */
> > +	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, PVT_ENA_EN);
> > +	readl(pvt->regs + PVT_DATA);
> > +
> > +	tout = PVT_TOUT_MIN / NSEC_PER_USEC;
> > +	usleep_range(tout, 2 * tout);
> 
> Since this IRQ is shared and level-triggered, won't generating an interrupt
> before the handler is registered cause an IRQ storm? The interrupt controller
> will fire continuously during the usleep_range(), which could cause the
> kernel's spurious IRQ detector to permanently disable the shared IRQ line.

The PVT IP is fully integrated and always powered, so performing the
eic7700_pvt_check_pwr() verification is not required. This check will be
removed in the v4 patch.

> 
> > +
> > +	readl(pvt->regs + PVT_DATA);
> > +	if (!(readl(pvt->regs + PVT_INT) & PVT_INT_STAT)) {
> > +		ret = -ENODEV;
> > +		dev_err(pvt->dev,
> > +			"Sensor is powered down - no interrupt generated\n");
> > +	}
> > +
> > +	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, 0);
> > +	eic7700_pvt_update(pvt->regs + PVT_INT, PVT_INT_CLR, PVT_INT_CLR);
> > +
> > +	return ret;
> > +}
> > +
> > +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_INT, PVT_INT_CLR, PVT_INT_CLR);
> > +	eic7700_pvt_update(pvt->regs + PVT_ENA, PVT_ENA_EN, 0);
> > +	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_SHARED | 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)
> > +{
> > +	struct device *dev = pvt->dev;
> > +	struct device_node *np = dev->of_node;
> > +	const char *node_label;
> > +	int type;
> > +	const char *names[2] = {"soc_pvt", "ddr_pvt"};
> > +
> > +	if (of_property_read_string(np, "label", &node_label)) {
> > +		dev_err(dev, "Missing 'label' property in DTS node\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (strcmp(node_label, "pvt0") == 0) {
> > +		type = 0;
> > +	} else if (strcmp(node_label, "pvt1") == 0) {
> > +		type = 1;
> > +	} else {
> > +		dev_err(pvt->dev, "Unsupported label: %s\n", node_label);
> > +		return -EINVAL;
> > +	}
> > +
> > +	pvt->hwmon = devm_hwmon_device_register_with_info(pvt->dev, names[type],
> > +							  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);
> > +}
> > +
> > +static int eic7700_pvt_probe(struct platform_device *pdev)
> > +{
> > +	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");
> > +
> > +	pvt->rst = devm_reset_control_get_exclusive_deasserted(&pdev->dev,
> > +							       NULL);
> > +	if (IS_ERR(pvt->rst))
> > +		return dev_err_probe(pvt->dev, PTR_ERR(pvt->rst),
> > +				     "Couldn't get reset control\n");
> > +
> > +	clk_prepare_enable(pvt->clk);
> > +
> > +	ret = eic7700_pvt_check_pwr(pvt);
> > +	if (ret)
> > +		return ret;
> > +
> > +	clk_disable_unprepare(pvt->clk);
> > +
> > +	ret = eic7700_pvt_init_iface(pvt);
> > +	if (ret)
> > +		return ret;
> 
> In eic7700_pvt_init_iface(pvt), the code accesses the device's registers.
> Since clk_disable_unprepare(pvt->clk) is called right before it, won't
> accessing the hardware registers here cause a bus fault? Should the clock be
> disabled after initialization instead?

We will move clk_disable_unprepare() to after eic7700_pvt_init_iface() in v4.

> 
> > +
> > +	ret = eic7700_pvt_request_irq(pvt);
> > +	if (ret)
> > +		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)
> > +		return dev_err_probe(&pdev->dev, ret,
> > +				     "Can't register PM cleanup\n");
> > +
> > +	ret = eic7700_pvt_create_hwmon(pvt);
> > +	if (ret)
> > +		return ret;
> 
> If eic7700_pvt_create_hwmon() fails, the function returns early. The devres
> action disables runtime PM, but it doesn't balance the
> pm_runtime_get_noresume(). Does this leak the usage counter on probe failure?

We will add proper error handling to ensure pm_runtime_put_noidle() is
called on probe failure paths to balance the pm_runtime_get_noresume()
reference.

> 
> > +
> > +	pm_runtime_put_autosuspend(&pdev->dev);
> > +
> > +	return 0;
> > +}
> > +
> > +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);
> > +
> Does this need a synchronize_irq(pvt->irq) before disabling the clock? Since
> the IRQ is shared, a handler might be executing mid-flight on another CPU
> when the clock is disabled, which could cause a bus fault.

It has been confirmed that the PVT interrupt is not shared. Therefore,
synchronize_irq() is not required.

> 
> > +	return 0;
> > +}
> > +
> > +static int __maybe_unused eic7700_pvt_suspend(struct device *dev)
> > +{
> > +	int ret = 0;
> > +
> > +	if (!pm_runtime_status_suspended(dev)) {
> > +		ret = eic7700_pvt_runtime_suspend(dev);
> > +		if (ret) {
> > +			dev_err(dev, "Failed to suspend: %d\n", ret);
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int __maybe_unused eic7700_pvt_resume(struct device *dev)
> > +{
> > +	int ret = 0;
> > +
> > +	if (!pm_runtime_status_suspended(dev)) {
> > +		ret = eic7700_pvt_runtime_resume(dev);
> > +		if (ret) {
> > +			dev_err(dev, "Failed to resume: %d\n", ret);
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct dev_pm_ops eic7700_pvt_pm_ops = {
> > +	SYSTEM_SLEEP_PM_OPS(eic7700_pvt_suspend, eic7700_pvt_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_sleep_ptr(&eic7700_pvt_pm_ops),
> 
> Since eic7700_pvt_pm_ops contains runtime PM callbacks, using pm_sleep_ptr()
> will drop the entire structure if CONFIG_PM_SLEEP is disabled but CONFIG_PM
> is enabled. Should this use pm_ptr() instead?

We will use pm_ptr() in the v4 patch.

Best regards,
Huan He