hwmon: (ctf2301) Add support for CTF2301

Link https://www.sensylink.com/

Signed-off-by Troy Mitchell <[email protected]>

---
 Documentation/devicetree/bindings/vendor-prefixes.yaml | 2 ++
 1 file changed, 2 insertions(+)

Documentation/devicetree/bindings/vendor-prefixes.yaml +2 -0

index 77160cd47f54079a39f35b570d69f7c4c2274724..ea4011d64ab9081d212a738839849d5814cf6c98 100644
@@ -1353,6 +1353,8 @@ patternProperties:
     description: Sensirion AG
   "^sensortek,.*":
     description: Sensortek Technology Corporation
+  "^sensylink,.*":
+    description: Sensylink Microelectronics Technology Co., Ltd.
   "^sercomm,.*":
     description: Sercomm (Suzhou) Corporation
   "^sff,.*":

Quoted 2 lines · Troy Mitchell

Link https://www.sensylink.com/

This is not an appropriate patch description.

Quoted 19 lines

Signed-off-by Troy Mitchell <[email protected]>

---
 Documentation/devicetree/bindings/vendor-prefixes.yaml | 2 ++
 1 file changed, 2 insertions(+)

Documentation/devicetree/bindings/vendor-prefixes.yaml +2 -0

index 77160cd47f54079a39f35b570d69f7c4c2274724..ea4011d64ab9081d212a738839849d5814cf6c98 100644
@@ -1353,6 +1353,8 @@ patternProperties:
     description: Sensirion AG
   "^sensortek,.*":
     description: Sensortek Technology Corporation
+  "^sensylink,.*":
+    description: Sensylink Microelectronics Technology Co., Ltd.
   "^sercomm,.*":
     description: Sercomm (Suzhou) Corporation
   "^sff,.*":

Add dt-binding for the hwmon driver of Sensylink's CTF2301 chip.

Signed-off-by Troy Mitchell <[email protected]>

---
 .../bindings/hwmon/sensylink,ctf2301.yaml          | 49 ++++++++++++++++++++++
 1 file changed, 49 insertions(+)

Add dt-binding for the hwmon driver of Sensylink's CTF2301 chip.

Signed-off-by Troy Mitchell <[email protected]>

---
 .../bindings/hwmon/sensylink,ctf2301.yaml          | 49 ++++++++++++++++++++++
 1 file changed, 49 insertions(+)

Documentation/devicetree/bindings/hwmon/sensylink,ctf2301.yaml new file +8 -0

new file mode 100644
index 0000000000000000000000000000000000000000..fe98f5b578320bc1b43ff88f76667990821a88f7
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/sensylink,ctf2301.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sensylink CTF2301 system-level thermal management solution chip
+

Documentation/devicetree/bindings/hwmon/sensylink,ctf2301.yaml new file +31 -0

+    - An integrated PWM fan controller.
+    - A 1-channel fan speed monitor (TACH input) for RPM measurement.
+
+  Datasheets:
+    https://www.sensylink.com/upload/1/net.sensylink.portal/1689557281035.pdf
+
+properties:
+  compatible:
+    const:
+      - sensylink,ctf2301
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        ctf2301@4c {
+            compatible = "sensylink,ctf2301";
+            reg = <0x4c>;
+        };
+    };

Signature · 2 lines

-- 
2.51.0

Documentation/devicetree/bindings/hwmon/sensylink,ctf2301.yaml line 18

Quoted 10 lines · Troy Mitchell

Add dt-binding for the hwmon driver of Sensylink's CTF2301 chip.

Signed-off-by Troy Mitchell <[email protected]>

---
 .../bindings/hwmon/sensylink,ctf2301.yaml          | 49 ++++++++++++++++++++++
 1 file changed, 49 insertions(+)

Documentation/devicetree/bindings/hwmon/sensylink,ctf2301.yaml new file +4 -0

+description: |
+  The CTF2301B is an I2C/SMBus compatible device featuring:
+    - One local temperature sensor with ±0.5°C accuracy and 0.0625°C resolution.
+    - One remote temperature sensor for external diode-connected transistors, offering ±1°C accuracy and 0.125°C resolution (temperature range: -40°C to +125°C).

Wrap at 80 chars.

Documentation/devicetree/bindings/hwmon/sensylink,ctf2301.yaml line 28

Quoted 11 lines

Documentation/devicetree/bindings/hwmon/sensylink,ctf2301.yaml new file +10 -0

+    - An integrated PWM fan controller.
+    - A 1-channel fan speed monitor (TACH input) for RPM measurement.
+
+  Datasheets:
+    https://www.sensylink.com/upload/1/net.sensylink.portal/1689557281035.pdf
+
+properties:
+  compatible:
+    const:
+      - sensylink,ctf2301

Quoted 25 lines

Documentation/devicetree/bindings/hwmon/sensylink,ctf2301.yaml new file +21 -0

+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        ctf2301@4c {
+            compatible = "sensylink,ctf2301";
+            reg = <0x4c>;
+        };
+    };

Signature · 2 lines

-- 
2.51.0

This commit introduces driver for the Sensylink CTF2301 system-level thermal management solution chip.

Currently, the driver does NOT support the Auto-Temp mode of the PWM fan controller, which provides closed-loop automatic fan speed control based on temperature.

Now this driver supports:
- Reading local temperature.
- Reading remote temperature.
- Controlling the PWM fan output in Direct-DCY mode (direct duty cycle control).
- Monitoring fan speed via the TACH input (RPM measurement).

Signed-off-by Troy Mitchell <[email protected]>

---
 drivers/hwmon/Kconfig   |  11 ++
 drivers/hwmon/Makefile  |   1 +
 drivers/hwmon/ctf2301.c | 326 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 338 insertions(+)

drivers/hwmon/Kconfig +11 -0

index 9d28fcf7cd2a6f9e2f54694a717bd85ff4047b46..2120d891e549795c3f3416d08f71916af714f6b6 100644
@@ -537,6 +537,17 @@ config SENSORS_CROS_EC
 	  This driver can also be built as a module. If so, the module
 	  will be called cros_ec_hwmon.
 
+config SENSORS_CTF2301
+	tristate "Sensylink CTF2301"
+	depends on I2C
+	select REGMAP
+	help
+	  If you say yes here you get support for Sensylink CTF2301
+	  sensor chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called ctf2301.
+
 config SENSORS_DRIVETEMP
 	tristate "Hard disk drives with temperature sensors"
 	depends on SCSI && ATA

drivers/hwmon/Makefile +1 -0

index cd8bc4752b4dbf015c6eb46157626f4e8f87dfae..12f2894ce8d5fbfd942409f6c43d78fbdece57b4 100644
@@ -65,6 +65,7 @@ obj-$(CONFIG_SENSORS_CORETEMP)	+= coretemp.o
 obj-$(CONFIG_SENSORS_CORSAIR_CPRO) += corsair-cpro.o
 obj-$(CONFIG_SENSORS_CORSAIR_PSU) += corsair-psu.o
 obj-$(CONFIG_SENSORS_CROS_EC)	+= cros_ec_hwmon.o
+obj-$(CONFIG_SENSORS_CTF2301)	+= ctf2301.o
 obj-$(CONFIG_SENSORS_DA9052_ADC)+= da9052-hwmon.o
 obj-$(CONFIG_SENSORS_DA9055)+= da9055-hwmon.o
 obj-$(CONFIG_SENSORS_DELL_SMM)	+= dell-smm-hwmon.o

drivers/hwmon/ctf2301.c new file +96 -0

new file mode 100644
index 0000000000000000000000000000000000000000..2fea4d195519ea34c1d4bf67456098b225d4d13c
@@ -0,0 +1,326 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for CTF2301 system-level thermal management solution chip
+ * Datasheet: https://www.sensylink.com/upload/1/net.sensylink.portal/1689557281035.pdf
+ *
+ * Copyright (C) 2025 Troy Mitchell <[email protected]>
+ */
+
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#define PWM_PARENT_CLOCK			360000
+
+#define CTF2301_LOCAL_TEMP_MSB			0x00
+#define CTF2301_RMT_TEMP_MSB			0x01
+#define CTF2301_ALERT_STATUS			0x02
+#define CTF2301_GLOBAL_CFG			0x03
+#define CTF2301_RMT_TEMP_LSB			0x10
+#define CTF2301_LOCAL_TEMP_LSB			0x15
+#define CTF2301_ALERT_MASK			0x16
+#define	CTF2301_ENHANCED_CFG			0x45
+#define CTF2301_TACH_COUNT_LSB			0x46
+#define CTF2301_TACH_COUNT_MSB			0x47
+#define CTF2301_PWM_AND_TACH_CFG		0x4a
+#define CTF2301_PWM_VALUE			0x4c
+#define CTF2301_PWM_FREQ			0x4d
+#define CTF2301_RMT_DIODE_TEMP_FILTER		0xbf
+
+/* remote diode fault alarm */
+#define ALERT_STATUS_RDFA			BIT(2)
+
+/* alert interrupts enable  */
+#define GLOBAL_CFG_ALERT_MASK			BIT(7)
+/* tach input enable  */
+#define GLOBAL_CFG_TACH_SEL			BIT(2)
+
+/* local high temperature alarm mask */
+#define ALERT_MASK_LHAM				BIT(6)
+/* remote high temperature alarm mask */
+#define ALERT_MASK_RHAM				BIT(4)
+/* remote low temperature alarm mask */
+#define ALERT_MASK_RLAM				BIT(3)
+/* remote t_crit alarm mask */
+#define ALERT_MASK_RCAM				BIT(1)
+/* tachometer alarm mask */
+#define ALERT_MASK_TCHAM			BIT(0)
+
+#define ALERT_MASK_ALL				(ALERT_MASK_LHAM | ALERT_MASK_RHAM | \
+						ALERT_MASK_RLAM | ALERT_MASK_RCAM | \
+						ALERT_MASK_TCHAM)
+
+/* enables signed format for high and t_crit setpoints */
+#define ENHANGCED_CFG_USF			BIT(3)
+
+/* PWM Programming enable */
+#define PWM_AND_TACH_CFG_PWPGM			BIT(5)
+
+#define PWM_DEFAULT_FREQ_CODE			0x17
+
+
+struct ctf2301 {
+	struct i2c_client *client;
+
+	struct regmap *regmap;
+
+	unsigned int pwm_freq_code;
+};
+
+static int ctf2301_read_temp(struct device *dev, u32 attr, int channel, long *val)
+{
+	int regval[2], raw, err, flag = 1, shift = 4, scale = 625;
+	struct ctf2301 *ctf2301 = dev_get_drvdata(dev);
+	unsigned int reg_msb = CTF2301_LOCAL_TEMP_MSB,
+		     reg_lsb = CTF2301_LOCAL_TEMP_LSB;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		if (channel != 0 && channel != 1)
+			return -EOPNOTSUPP;
+
+		if (channel == 1) {
+			err = regmap_read(ctf2301->regmap, CTF2301_ALERT_STATUS, regval);
+			if (err)
+				return err;
+
+			if (regval[0] & ALERT_STATUS_RDFA)
+				return -ENODEV;
+
+			shift = 5;
+			scale = 1250;
+			reg_msb = CTF2301_RMT_TEMP_MSB;
+			reg_lsb = CTF2301_RMT_TEMP_LSB;
+		}

drivers/hwmon/ctf2301.c new file +220 -0

+
+		raw = (s16)((regval[0] << 8) | regval[1]);
+
+		raw >>= shift;
+
+		*val = raw * scale * flag;
+
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int ctf2301_read_fan(struct device *dev, u32 attr, long *val)
+{
+	struct ctf2301 *ctf2301 = dev_get_drvdata(dev);
+	int regval[2], err, speed;
+
+	switch (attr) {
+	case hwmon_fan_input:
+		err = regmap_read(ctf2301->regmap, CTF2301_TACH_COUNT_MSB, regval);
+		if (err)
+			return err;
+
+		err = regmap_read(ctf2301->regmap, CTF2301_TACH_COUNT_LSB, regval + 1);
+		if (err)
+			return err;
+
+		speed = (regval[0] << 8) | regval[1];
+
+		*val = (unsigned int)(1 * (5400000 / speed));
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int ctf2301_write_pwm(struct device *dev, u32 attr, long val)
+{
+	struct ctf2301 *ctf2301 = dev_get_drvdata(dev);
+	int err, map_val;
+
+	dev_err(dev, "write pwm: %d", attr);
+
+	switch (attr) {
+	case hwmon_pwm_input:
+		map_val = (val * ctf2301->pwm_freq_code * 2) / 255;
+		dev_err(dev, "val:%ld, map_val: %d", val, map_val);
+		err = regmap_write(ctf2301->regmap, CTF2301_PWM_VALUE, map_val);
+		if (err)
+			return err;
+		break;
+	case hwmon_pwm_freq:
+		ctf2301->pwm_freq_code = DIV_ROUND_UP(PWM_PARENT_CLOCK, val) / 2;
+		dev_err(dev, "pwm_freq_code: %d", ctf2301->pwm_freq_code);
+		err = regmap_write(ctf2301->regmap, CTF2301_PWM_FREQ, ctf2301->pwm_freq_code);
+		if (err)
+			return err;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static umode_t ctf2301_is_visible(const void *drvdata,
+				 enum hwmon_sensor_types type,
+				 u32 attr, int channel)
+{
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+		case hwmon_pwm_freq:
+			return 0644;
+		default:
+			return 0;
+		}
+	default:
+		return 0;
+	}
+}
+
+static int ctf2301_read(struct device *dev, enum hwmon_sensor_types type,
+		       u32 attr, int channel, long *val)
+{
+	switch (type) {
+	case hwmon_temp:
+		return ctf2301_read_temp(dev, attr, channel, val);
+	case hwmon_fan:
+		return ctf2301_read_fan(dev, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static int ctf2301_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
+{
+	switch (type) {
+	case hwmon_pwm:
+		return ctf2301_write_pwm(dev, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static const struct hwmon_channel_info * const ctf2301_info[] = {
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT, HWMON_T_INPUT),
+	HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_FREQ),
+	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
+	NULL
+};
+
+static const struct hwmon_ops ctf2301_hwmon_ops = {
+	.is_visible = ctf2301_is_visible,
+	.read = ctf2301_read,
+	.write = ctf2301_write
+};
+
+static const struct hwmon_chip_info ctf2301_chip_info = {
+	.ops = &ctf2301_hwmon_ops,
+	.info = ctf2301_info,
+};
+
+static const struct regmap_config ctf2301_regmap_config = {
+	.max_register = CTF2301_RMT_DIODE_TEMP_FILTER,
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int ctf2301_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct device *hwmon_dev;
+	struct ctf2301 *ctf2301;
+	int err;
+
+	ctf2301 = devm_kzalloc(dev, sizeof(*ctf2301), GFP_KERNEL);
+	if (!ctf2301)
+		return -ENOMEM;
+	ctf2301->client = client;
+
+	ctf2301->regmap = devm_regmap_init_i2c(client, &ctf2301_regmap_config);
+	if (IS_ERR(ctf2301->regmap))
+		return dev_err_probe(dev, PTR_ERR(ctf2301->regmap),
+				     "failed to allocate register map");
+
+	err = regmap_write(ctf2301->regmap, CTF2301_GLOBAL_CFG,
+			   GLOBAL_CFG_ALERT_MASK | GLOBAL_CFG_TACH_SEL);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "failed to write CTF2301_GLOBAL_CFG register");
+
+	/*err = regmap_write(ctf2301->regmap, CTF2301_ALERT_MASK, ALERT_MASK_ALL);*/
+	/*if (err)*/
+		/*return dev_err_probe(dev, err,*/
+				     /*"failed to write CTF2301_ALERT_MASK");*/
+
+	err = regmap_write(ctf2301->regmap, CTF2301_ENHANCED_CFG, ENHANGCED_CFG_USF);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "failed to write CTF2301_ENHANCED_CFG");
+
+	err = regmap_write(ctf2301->regmap, CTF2301_PWM_AND_TACH_CFG, PWM_AND_TACH_CFG_PWPGM);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "failed to write CTF2301_PWM_AND_TACH_CFG");
+
+	ctf2301->pwm_freq_code = PWM_DEFAULT_FREQ_CODE;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, ctf2301,
+							 &ctf2301_chip_info,
+							 NULL);
+	if (IS_ERR(hwmon_dev))
+		return dev_err_probe(dev, PTR_ERR(hwmon_dev),
+				     "failed to register hwmon device");
+
+	return 0;
+}
+
+static const struct of_device_id ctf2301_of_match[] = {
+	{ .compatible = "sensylink,ctf2301", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ctf2301_of_match);
+
+static struct i2c_driver ctf2301_driver = {
+	.driver = {
+		.name	= "ctf2301",
+		.of_match_table = of_match_ptr(ctf2301_of_match),
+	},
+	.probe		= ctf2301_probe,
+};
+module_i2c_driver(ctf2301_driver);
+
+MODULE_AUTHOR("Troy Mitchell <[email protected]>");
+MODULE_DESCRIPTION("ctf2301 driver");
+MODULE_LICENSE("GPL");

Signature · 2 lines

-- 
2.51.0

This commit introduces driver for the Sensylink CTF2301 system-level thermal management solution chip.

Currently, the driver does NOT support the Auto-Temp mode of the PWM fan controller, which provides closed-loop automatic fan speed control based on temperature.

Now this driver supports:

- Reading local temperature.
- Reading remote temperature.
- Controlling the PWM fan output in Direct-DCY mode (direct duty cycle control).
- Monitoring fan speed via the TACH input (RPM measurement).

Signed-off-by Troy Mitchell <[email protected]>

---
 drivers/hwmon/Kconfig   |  11 ++
 drivers/hwmon/Makefile  |   1 +
 drivers/hwmon/ctf2301.c | 326 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 338 insertions(+)

drivers/hwmon/Kconfig +11 -0

index 9d28fcf7cd2a6f9e2f54694a717bd85ff4047b46..2120d891e549795c3f3416d08f71916af714f6b6 100644
@@ -537,6 +537,17 @@ config SENSORS_CROS_EC
 	  This driver can also be built as a module. If so, the module
 	  will be called cros_ec_hwmon.
 
+config SENSORS_CTF2301
+	tristate "Sensylink CTF2301"
+	depends on I2C
+	select REGMAP
+	help
+	  If you say yes here you get support for Sensylink CTF2301
+	  sensor chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called ctf2301.
+
 config SENSORS_DRIVETEMP
 	tristate "Hard disk drives with temperature sensors"
 	depends on SCSI && ATA

drivers/hwmon/Makefile +1 -0

index cd8bc4752b4dbf015c6eb46157626f4e8f87dfae..12f2894ce8d5fbfd942409f6c43d78fbdece57b4 100644
@@ -65,6 +65,7 @@ obj-$(CONFIG_SENSORS_CORETEMP)	+= coretemp.o
 obj-$(CONFIG_SENSORS_CORSAIR_CPRO) += corsair-cpro.o
 obj-$(CONFIG_SENSORS_CORSAIR_PSU) += corsair-psu.o
 obj-$(CONFIG_SENSORS_CROS_EC)	+= cros_ec_hwmon.o
+obj-$(CONFIG_SENSORS_CTF2301)	+= ctf2301.o
 obj-$(CONFIG_SENSORS_DA9052_ADC)+= da9052-hwmon.o
 obj-$(CONFIG_SENSORS_DA9055)+= da9055-hwmon.o
 obj-$(CONFIG_SENSORS_DELL_SMM)	+= dell-smm-hwmon.o

drivers/hwmon/ctf2301.c new file +7 -0

new file mode 100644
index 0000000000000000000000000000000000000000..2fea4d195519ea34c1d4bf67456098b225d4d13c
@@ -0,0 +1,326 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for CTF2301 system-level thermal management solution chip
+ * Datasheet: https://www.sensylink.com/upload/1/net.sensylink.portal/1689557281035.pdf
+ *
+ * Copyright (C) 2025 Troy Mitchell <[email protected]>
+ */

drivers/hwmon/ctf2301.c new file +30 -0

+#define	CTF2301_ENHANCED_CFG			0x45
+#define CTF2301_TACH_COUNT_LSB			0x46
+#define CTF2301_TACH_COUNT_MSB			0x47
+#define CTF2301_PWM_AND_TACH_CFG		0x4a
+#define CTF2301_PWM_VALUE			0x4c
+#define CTF2301_PWM_FREQ			0x4d
+#define CTF2301_RMT_DIODE_TEMP_FILTER		0xbf
+
+/* remote diode fault alarm */
+#define ALERT_STATUS_RDFA			BIT(2)
+
+/* alert interrupts enable  */
+#define GLOBAL_CFG_ALERT_MASK			BIT(7)
+/* tach input enable  */
+#define GLOBAL_CFG_TACH_SEL			BIT(2)
+
+/* local high temperature alarm mask */
+#define ALERT_MASK_LHAM				BIT(6)
+/* remote high temperature alarm mask */
+#define ALERT_MASK_RHAM				BIT(4)
+/* remote low temperature alarm mask */
+#define ALERT_MASK_RLAM				BIT(3)
+/* remote t_crit alarm mask */
+#define ALERT_MASK_RCAM				BIT(1)
+/* tachometer alarm mask */
+#define ALERT_MASK_TCHAM			BIT(0)
+
+#define ALERT_MASK_ALL				(ALERT_MASK_LHAM | ALERT_MASK_RHAM | \
+						ALERT_MASK_RLAM | ALERT_MASK_RCAM | \
+						ALERT_MASK_TCHAM)

drivers/hwmon/ctf2301.c new file +4 -0

+
+			shift = 5;
+			scale = 1250;
+			reg_msb = CTF2301_RMT_TEMP_MSB;

drivers/hwmon/ctf2301.c new file +4 -0

+		break;
+	default:
+		return -EOPNOTSUPP;
+	}

drivers/hwmon/ctf2301.c new file +162 -0

+		dev_err(dev, "pwm_freq_code: %d", ctf2301->pwm_freq_code);
+		err = regmap_write(ctf2301->regmap, CTF2301_PWM_FREQ, ctf2301->pwm_freq_code);
+		if (err)
+			return err;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static umode_t ctf2301_is_visible(const void *drvdata,
+				 enum hwmon_sensor_types type,
+				 u32 attr, int channel)
+{
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+		case hwmon_pwm_freq:
+			return 0644;
+		default:
+			return 0;
+		}
+	default:
+		return 0;
+	}
+}
+
+static int ctf2301_read(struct device *dev, enum hwmon_sensor_types type,
+		       u32 attr, int channel, long *val)
+{
+	switch (type) {
+	case hwmon_temp:
+		return ctf2301_read_temp(dev, attr, channel, val);
+	case hwmon_fan:
+		return ctf2301_read_fan(dev, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static int ctf2301_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
+{
+	switch (type) {
+	case hwmon_pwm:
+		return ctf2301_write_pwm(dev, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static const struct hwmon_channel_info * const ctf2301_info[] = {
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT, HWMON_T_INPUT),
+	HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_FREQ),
+	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
+	NULL
+};
+
+static const struct hwmon_ops ctf2301_hwmon_ops = {
+	.is_visible = ctf2301_is_visible,
+	.read = ctf2301_read,
+	.write = ctf2301_write
+};
+
+static const struct hwmon_chip_info ctf2301_chip_info = {
+	.ops = &ctf2301_hwmon_ops,
+	.info = ctf2301_info,
+};
+
+static const struct regmap_config ctf2301_regmap_config = {
+	.max_register = CTF2301_RMT_DIODE_TEMP_FILTER,
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int ctf2301_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct device *hwmon_dev;
+	struct ctf2301 *ctf2301;
+	int err;
+
+	ctf2301 = devm_kzalloc(dev, sizeof(*ctf2301), GFP_KERNEL);
+	if (!ctf2301)
+		return -ENOMEM;
+	ctf2301->client = client;
+
+	ctf2301->regmap = devm_regmap_init_i2c(client, &ctf2301_regmap_config);
+	if (IS_ERR(ctf2301->regmap))
+		return dev_err_probe(dev, PTR_ERR(ctf2301->regmap),
+				     "failed to allocate register map");
+
+	err = regmap_write(ctf2301->regmap, CTF2301_GLOBAL_CFG,
+			   GLOBAL_CFG_ALERT_MASK | GLOBAL_CFG_TACH_SEL);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "failed to write CTF2301_GLOBAL_CFG register");
+
+	/*err = regmap_write(ctf2301->regmap, CTF2301_ALERT_MASK, ALERT_MASK_ALL);*/
+	/*if (err)*/
+		/*return dev_err_probe(dev, err,*/
+				     /*"failed to write CTF2301_ALERT_MASK");*/
+
+	err = regmap_write(ctf2301->regmap, CTF2301_ENHANCED_CFG, ENHANGCED_CFG_USF);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "failed to write CTF2301_ENHANCED_CFG");
+
+	err = regmap_write(ctf2301->regmap, CTF2301_PWM_AND_TACH_CFG, PWM_AND_TACH_CFG_PWPGM);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "failed to write CTF2301_PWM_AND_TACH_CFG");
+
+	ctf2301->pwm_freq_code = PWM_DEFAULT_FREQ_CODE;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, ctf2301,
+							 &ctf2301_chip_info,
+							 NULL);
+	if (IS_ERR(hwmon_dev))
+		return dev_err_probe(dev, PTR_ERR(hwmon_dev),
+				     "failed to register hwmon device");
+
+	return 0;
+}
+
+static const struct of_device_id ctf2301_of_match[] = {
+	{ .compatible = "sensylink,ctf2301", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ctf2301_of_match);
+
+static struct i2c_driver ctf2301_driver = {
+	.driver = {
+		.name	= "ctf2301",
+		.of_match_table = of_match_ptr(ctf2301_of_match),
+	},
+	.probe		= ctf2301_probe,
+};
+module_i2c_driver(ctf2301_driver);
+
+MODULE_AUTHOR("Troy Mitchell <[email protected]>");
+MODULE_DESCRIPTION("ctf2301 driver");
+MODULE_LICENSE("GPL");

On Tue, Sep 16, 2025 at 12:46:46PM +0800, Troy Mitchell wrote:

Quoted 1 line

drivers/hwmon/ctf2301.c +0 -0

drivers/hwmon/ctf2301.c

Quoted 2 lines

drivers/hwmon/ctf2301.c +2 -0

+
+#define CTF2301_LOCAL_TEMP_MSB			0x00

	LM90_REG_LOCAL_TEMP

Quoted 1 line

+#define CTF2301_RMT_TEMP_MSB 0x01

LM90_REG_REMOTE_TEMPH

Quoted 1 line

+#define CTF2301_ALERT_STATUS 0x02

	LM90_REG_STATUS

Quoted 1 line

+#define CTF2301_GLOBAL_CFG 0x03

	LM90_REG_CONFIG1

Quoted 1 line

+#define CTF2301_RMT_TEMP_LSB 0x10

LM90_REG_REMOTE_TEMPL

Quoted 1 line

+#define CTF2301_LOCAL_TEMP_LSB 0x15

	TMP451_REG_LOCAL_TEMPL

Quoted 1 line

+#define CTF2301_ALERT_MASK 0x16

	TMP461_REG_CHEN

So far this looks like a chip based on LM90 or TMP451/TMP461 with an added fan controller. I can not immediatey determine if it would be better to add the pwm/tach support to the lm90 driver. Given that the chip (based on registers) does support limits, which is not implemented here but essential for a chip like this, I would very much prefer adding support for it to the lm90 driver if possible.

The public datasheet does not provide register details, making it all but impossible to do a real evaluation. Any idea how to get a complete datasheet ?

Quoted 31 lines

drivers/hwmon/ctf2301.c +30 -0

+#define	CTF2301_ENHANCED_CFG			0x45
+#define CTF2301_TACH_COUNT_LSB			0x46
+#define CTF2301_TACH_COUNT_MSB			0x47
+#define CTF2301_PWM_AND_TACH_CFG		0x4a
+#define CTF2301_PWM_VALUE			0x4c
+#define CTF2301_PWM_FREQ			0x4d
+#define CTF2301_RMT_DIODE_TEMP_FILTER		0xbf
+
+/* remote diode fault alarm */
+#define ALERT_STATUS_RDFA			BIT(2)
+
+/* alert interrupts enable  */
+#define GLOBAL_CFG_ALERT_MASK			BIT(7)
+/* tach input enable  */
+#define GLOBAL_CFG_TACH_SEL			BIT(2)
+
+/* local high temperature alarm mask */
+#define ALERT_MASK_LHAM				BIT(6)
+/* remote high temperature alarm mask */
+#define ALERT_MASK_RHAM				BIT(4)
+/* remote low temperature alarm mask */
+#define ALERT_MASK_RLAM				BIT(3)
+/* remote t_crit alarm mask */
+#define ALERT_MASK_RCAM				BIT(1)
+/* tachometer alarm mask */
+#define ALERT_MASK_TCHAM			BIT(0)
+
+#define ALERT_MASK_ALL				(ALERT_MASK_LHAM | ALERT_MASK_RHAM | \
+						ALERT_MASK_RLAM | ALERT_MASK_RCAM | \
+						ALERT_MASK_TCHAM)

drivers/hwmon/ctf2301.c line 63

Quoted 10 lines

drivers/hwmon/ctf2301.c +10 -0

+
+/* enables signed format for high and t_crit setpoints */
+#define ENHANGCED_CFG_USF			BIT(3)
+
+/* PWM Programming enable */
+#define PWM_AND_TACH_CFG_PWPGM			BIT(5)
+
+#define PWM_DEFAULT_FREQ_CODE			0x17
+
+

No mode than one empty line. checkpatch --strict would tell. And, indeed, it reports:

total: 0 errors, 4 warnings, 3 checks, 350 lines checked

where

WARNING: Prefer a maximum 75 chars per line (possible unwrapped commit description?)
CHECK: Please don't use multiple blank lines
CHECK: Alignment should match open parenthesis

are relevant and need to be fixed.

drivers/hwmon/ctf2301.c line 65

Quoted 2 lines

drivers/hwmon/ctf2301.c +2 -0

+struct ctf2301 {
+	struct i2c_client *client;

Not used anywhere.

drivers/hwmon/ctf2301.c line 69

Quoted 4 lines

drivers/hwmon/ctf2301.c +4 -0

+
+	struct regmap *regmap;
+
+	unsigned int pwm_freq_code;

Unnecessary empty lines.

drivers/hwmon/ctf2301.c line 82

Quoted 13 lines

drivers/hwmon/ctf2301.c +13 -0

+};
+
+static int ctf2301_read_temp(struct device *dev, u32 attr, int channel, long *val)
+{
+	int regval[2], raw, err, flag = 1, shift = 4, scale = 625;
+	struct ctf2301 *ctf2301 = dev_get_drvdata(dev);
+	unsigned int reg_msb = CTF2301_LOCAL_TEMP_MSB,
+		     reg_lsb = CTF2301_LOCAL_TEMP_LSB;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		if (channel != 0 && channel != 1)
+			return -EOPNOTSUPP;

Should have been handled in is_visible function. It is, therefore this check is unnecessary.

drivers/hwmon/ctf2301.c line 90

Quoted 8 lines

drivers/hwmon/ctf2301.c +8 -0

+
+		if (channel == 1) {
+			err = regmap_read(ctf2301->regmap, CTF2301_ALERT_STATUS, regval);
+			if (err)
+				return err;
+
+			if (regval[0] & ALERT_STATUS_RDFA)
+				return -ENODEV;

Wrong return value. The device does obviously exist. This should return -ENODATA.

Quoted 4 lines

drivers/hwmon/ctf2301.c +4 -0

+
+			shift = 5;
+			scale = 1250;
+			reg_msb = CTF2301_RMT_TEMP_MSB;

drivers/hwmon/ctf2301.c line 104

Quoted 10 lines

drivers/hwmon/ctf2301.c +10 -0

+			reg_lsb = CTF2301_RMT_TEMP_LSB;
+		}
+
+		err = regmap_read(ctf2301->regmap, reg_msb, regval);
+		if (err)
+			return err;
+
+		err = regmap_read(ctf2301->regmap, reg_lsb, regval + 1);
+		if (err)
+			return err;

Consider using regmap_multi_reg_read() instead.

drivers/hwmon/ctf2301.c

Quoted 2 lines

drivers/hwmon/ctf2301.c +2 -0

+
+		dev_err(dev, "local temp: lsb->0x%x, msb->0x%x", regval[1], regval[0]);

Really ?

Stopping complete review here. The driver is obviously not ready for submission. Some more obvious comments below.

drivers/hwmon/ctf2301.c line 114

Quoted 8 lines

drivers/hwmon/ctf2301.c +8 -0

+
+		raw = (s16)((regval[0] << 8) | regval[1]);
+
+		raw >>= shift;
+
+		*val = raw * scale * flag;
+
+		break;

Drop empty lines.

drivers/hwmon/ctf2301.c line 122

Quoted 8 lines

drivers/hwmon/ctf2301.c +8 -0

+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int ctf2301_read_fan(struct device *dev, u32 attr, long *val)

There is only a single supported attribute, so passing its vbalue to this function and checking it adds unnecessary complexity. Just drop the parameter and all its complexity.

drivers/hwmon/ctf2301.c line 135

Quoted 13 lines

drivers/hwmon/ctf2301.c +13 -0

+{
+	struct ctf2301 *ctf2301 = dev_get_drvdata(dev);
+	int regval[2], err, speed;
+
+	switch (attr) {
+	case hwmon_fan_input:
+		err = regmap_read(ctf2301->regmap, CTF2301_TACH_COUNT_MSB, regval);
+		if (err)
+			return err;
+
+		err = regmap_read(ctf2301->regmap, CTF2301_TACH_COUNT_LSB, regval + 1);
+		if (err)
+			return err;

CTF2301_TACH_COUNT_LSB and CTF2301_TACH_COUNT_MSB are consecutive registers, so it should be possible to use regmap_bulk_read(). If not, consider using regmap_multi_reg_read() and explain why regmap_bulk_read() does not work.

drivers/hwmon/ctf2301.c line 138

Quoted 3 lines

drivers/hwmon/ctf2301.c +3 -0

+
+		speed = (regval[0] << 8) | regval[1];
+

speed can be 0.

drivers/hwmon/ctf2301.c line 139

Quoted 1 line

drivers/hwmon/ctf2301.c +1 -0

+		*val = (unsigned int)(1 * (5400000 / speed));

^^^^ what is this for ?

The typecast is unnecessary, and speed needs to be checked to ensure that there is no divide by zero error.

Quoted 4 lines

drivers/hwmon/ctf2301.c +4 -0

+		break;
+	default:
+		return -EOPNOTSUPP;
+	}

drivers/hwmon/ctf2301.c line 153

Quoted 10 lines

drivers/hwmon/ctf2301.c +10 -0

+
+	return 0;
+}
+
+static int ctf2301_write_pwm(struct device *dev, u32 attr, long val)
+{
+	struct ctf2301 *ctf2301 = dev_get_drvdata(dev);
+	int err, map_val;
+
+	dev_err(dev, "write pwm: %d", attr);

Not commmenting on those any further.

drivers/hwmon/ctf2301.c line 157

Quoted 4 lines

drivers/hwmon/ctf2301.c +4 -0

+
+	switch (attr) {
+	case hwmon_pwm_input:
+		map_val = (val * ctf2301->pwm_freq_code * 2) / 255;

val needs to be range checked, and the function needs to return -EINVAL if it is out of range. Also consider using DIV_ROUND_CLOSEST().

drivers/hwmon/ctf2301.c line 164

Quoted 7 lines

drivers/hwmon/ctf2301.c +7 -0

+		dev_err(dev, "val:%ld, map_val: %d", val, map_val);
+		err = regmap_write(ctf2301->regmap, CTF2301_PWM_VALUE, map_val);
+		if (err)
+			return err;
+		break;
+	case hwmon_pwm_freq:
+		ctf2301->pwm_freq_code = DIV_ROUND_UP(PWM_PARENT_CLOCK, val) / 2;

val needs to be clamped to its valid range.

Quoted 162 lines

drivers/hwmon/ctf2301.c +162 -0

+		dev_err(dev, "pwm_freq_code: %d", ctf2301->pwm_freq_code);
+		err = regmap_write(ctf2301->regmap, CTF2301_PWM_FREQ, ctf2301->pwm_freq_code);
+		if (err)
+			return err;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static umode_t ctf2301_is_visible(const void *drvdata,
+				 enum hwmon_sensor_types type,
+				 u32 attr, int channel)
+{
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+		case hwmon_pwm_freq:
+			return 0644;
+		default:
+			return 0;
+		}
+	default:
+		return 0;
+	}
+}
+
+static int ctf2301_read(struct device *dev, enum hwmon_sensor_types type,
+		       u32 attr, int channel, long *val)
+{
+	switch (type) {
+	case hwmon_temp:
+		return ctf2301_read_temp(dev, attr, channel, val);
+	case hwmon_fan:
+		return ctf2301_read_fan(dev, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static int ctf2301_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
+{
+	switch (type) {
+	case hwmon_pwm:
+		return ctf2301_write_pwm(dev, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static const struct hwmon_channel_info * const ctf2301_info[] = {
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT, HWMON_T_INPUT),
+	HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_FREQ),
+	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
+	NULL
+};
+
+static const struct hwmon_ops ctf2301_hwmon_ops = {
+	.is_visible = ctf2301_is_visible,
+	.read = ctf2301_read,
+	.write = ctf2301_write
+};
+
+static const struct hwmon_chip_info ctf2301_chip_info = {
+	.ops = &ctf2301_hwmon_ops,
+	.info = ctf2301_info,
+};
+
+static const struct regmap_config ctf2301_regmap_config = {
+	.max_register = CTF2301_RMT_DIODE_TEMP_FILTER,
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int ctf2301_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct device *hwmon_dev;
+	struct ctf2301 *ctf2301;
+	int err;
+
+	ctf2301 = devm_kzalloc(dev, sizeof(*ctf2301), GFP_KERNEL);
+	if (!ctf2301)
+		return -ENOMEM;
+	ctf2301->client = client;
+
+	ctf2301->regmap = devm_regmap_init_i2c(client, &ctf2301_regmap_config);
+	if (IS_ERR(ctf2301->regmap))
+		return dev_err_probe(dev, PTR_ERR(ctf2301->regmap),
+				     "failed to allocate register map");
+
+	err = regmap_write(ctf2301->regmap, CTF2301_GLOBAL_CFG,
+			   GLOBAL_CFG_ALERT_MASK | GLOBAL_CFG_TACH_SEL);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "failed to write CTF2301_GLOBAL_CFG register");
+
+	/*err = regmap_write(ctf2301->regmap, CTF2301_ALERT_MASK, ALERT_MASK_ALL);*/
+	/*if (err)*/
+		/*return dev_err_probe(dev, err,*/
+				     /*"failed to write CTF2301_ALERT_MASK");*/
+
+	err = regmap_write(ctf2301->regmap, CTF2301_ENHANCED_CFG, ENHANGCED_CFG_USF);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "failed to write CTF2301_ENHANCED_CFG");
+
+	err = regmap_write(ctf2301->regmap, CTF2301_PWM_AND_TACH_CFG, PWM_AND_TACH_CFG_PWPGM);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "failed to write CTF2301_PWM_AND_TACH_CFG");
+
+	ctf2301->pwm_freq_code = PWM_DEFAULT_FREQ_CODE;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, ctf2301,
+							 &ctf2301_chip_info,
+							 NULL);
+	if (IS_ERR(hwmon_dev))
+		return dev_err_probe(dev, PTR_ERR(hwmon_dev),
+				     "failed to register hwmon device");
+
+	return 0;
+}
+
+static const struct of_device_id ctf2301_of_match[] = {
+	{ .compatible = "sensylink,ctf2301", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ctf2301_of_match);
+
+static struct i2c_driver ctf2301_driver = {
+	.driver = {
+		.name	= "ctf2301",
+		.of_match_table = of_match_ptr(ctf2301_of_match),
+	},
+	.probe		= ctf2301_probe,
+};
+module_i2c_driver(ctf2301_driver);
+
+MODULE_AUTHOR("Troy Mitchell <[email protected]>");
+MODULE_DESCRIPTION("ctf2301 driver");
+MODULE_LICENSE("GPL");

Hi Guenter, Thanks for your review. There are many things to improve in this driver.

Quoted 1 line · Guenter Roeck

On Tue, Sep 16, 2025 at 12:46:46PM +0800, Troy Mitchell wrote:

[...]

Quoted 1 line

Quoted 1 line

drivers/hwmon/ctf2301.c +0 -0

[...]

Quoted 24 lines

drivers/hwmon/ctf2301.c

Quoted 2 lines

drivers/hwmon/ctf2301.c +2 -0

+
+#define CTF2301_LOCAL_TEMP_MSB			0x00

	LM90_REG_LOCAL_TEMP

Quoted 1 line

+#define CTF2301_RMT_TEMP_MSB 0x01

LM90_REG_REMOTE_TEMPH

Quoted 1 line

+#define CTF2301_ALERT_STATUS 0x02

	LM90_REG_STATUS

Quoted 1 line

+#define CTF2301_GLOBAL_CFG 0x03

	LM90_REG_CONFIG1

Quoted 1 line

+#define CTF2301_RMT_TEMP_LSB 0x10

LM90_REG_REMOTE_TEMPL

Quoted 1 line

+#define CTF2301_LOCAL_TEMP_LSB 0x15

	TMP451_REG_LOCAL_TEMPL

Quoted 1 line

+#define CTF2301_ALERT_MASK 0x16

	TMP461_REG_CHEN

So far this looks like a chip based on LM90 or TMP451/TMP461 with an added fan controller. I can not immediatey determine if it would be better to add the pwm/tach support to the lm90 driver. Given that the chip (based on registers) does support limits, which is not implemented here but essential for a chip like this, I would very much prefer adding support for it to the lm90 driver if possible.

Quoted 3 lines

The public datasheet does not provide register details, making it all but impossible to do a real evaluation. Any idea how to get a complete datasheet ?

Yeah, more register info at [1].
I've checked the detailed review below,
but I'll hold off on sending v2 until you decide if we really need a new driver.

Is this chip more like the LM63, by the way?

Quoted 39 lines · Troy Mitchell

Hi Guenter, Thanks for your review. There are many things to improve in this driver.

Quoted 1 line · Guenter Roeck

On Tue, Sep 16, 2025 at 12:46:46PM +0800, Troy Mitchell wrote:

[...]

Quoted 1 line

Quoted 1 line

drivers/hwmon/ctf2301.c +0 -0

[...]

Quoted 24 lines

drivers/hwmon/ctf2301.c

Quoted 2 lines

drivers/hwmon/ctf2301.c +2 -0

+
+#define CTF2301_LOCAL_TEMP_MSB			0x00

	LM90_REG_LOCAL_TEMP

Quoted 1 line

+#define CTF2301_RMT_TEMP_MSB 0x01

LM90_REG_REMOTE_TEMPH

Quoted 1 line

+#define CTF2301_ALERT_STATUS 0x02

	LM90_REG_STATUS

Quoted 1 line

+#define CTF2301_GLOBAL_CFG 0x03

	LM90_REG_CONFIG1

Quoted 1 line

+#define CTF2301_RMT_TEMP_LSB 0x10

LM90_REG_REMOTE_TEMPL

Quoted 1 line

+#define CTF2301_LOCAL_TEMP_LSB 0x15

	TMP451_REG_LOCAL_TEMPL

Quoted 1 line

+#define CTF2301_ALERT_MASK 0x16

	TMP461_REG_CHEN

So far this looks like a chip based on LM90 or TMP451/TMP461 with an added fan controller. I can not immediatey determine if it would be better to add the pwm/tach support to the lm90 driver. Given that the chip (based on registers) does support limits, which is not implemented here but essential for a chip like this, I would very much prefer adding support for it to the lm90 driver if possible.

Quoted 3 lines

The public datasheet does not provide register details, making it all but impossible to do a real evaluation. Any idea how to get a complete datasheet ?

Yeah, more register info at [1].
I've checked the detailed review below,
but I'll hold off on sending v2 until you decide if we really need a new driver.

Quoted 2 lines

Is this chip more like the LM63, by the way?

Good catch. Yes, looks like you are correct. LM63 is an almost perfect match. CTF2301 has a couple of extra registers, mostly local setpoint and temp LSB plus the registers in the 0x3x range. Actually, those registers _are_ defined for LM96163, so that chip is an even closer match.

What happens if you just instantiate the lm63 driver, possibly after updating the detect function ?

Guenter

Quoted 43 lines · Guenter Roeck

Quoted 41 lines · Troy Mitchell

Hi Guenter, Thanks for your review. There are many things to improve in this driver.

Quoted 1 line · Guenter Roeck

On Tue, Sep 16, 2025 at 12:46:46PM +0800, Troy Mitchell wrote:

[...]

Quoted 1 line

Quoted 1 line

drivers/hwmon/ctf2301.c +0 -0

[...]

Quoted 24 lines

drivers/hwmon/ctf2301.c

Quoted 2 lines

drivers/hwmon/ctf2301.c +2 -0

+
+#define CTF2301_LOCAL_TEMP_MSB			0x00

	LM90_REG_LOCAL_TEMP

Quoted 1 line

+#define CTF2301_RMT_TEMP_MSB 0x01

LM90_REG_REMOTE_TEMPH

Quoted 1 line

+#define CTF2301_ALERT_STATUS 0x02

	LM90_REG_STATUS

Quoted 1 line

+#define CTF2301_GLOBAL_CFG 0x03

	LM90_REG_CONFIG1

Quoted 1 line

+#define CTF2301_RMT_TEMP_LSB 0x10

LM90_REG_REMOTE_TEMPL

Quoted 1 line

+#define CTF2301_LOCAL_TEMP_LSB 0x15

	TMP451_REG_LOCAL_TEMPL

Quoted 1 line

+#define CTF2301_ALERT_MASK 0x16

	TMP461_REG_CHEN

So far this looks like a chip based on LM90 or TMP451/TMP461 with an added fan controller. I can not immediatey determine if it would be better to add the pwm/tach support to the lm90 driver. Given that the chip (based on registers) does support limits, which is not implemented here but essential for a chip like this, I would very much prefer adding support for it to the lm90 driver if possible.

Quoted 3 lines

The public datasheet does not provide register details, making it all but impossible to do a real evaluation. Any idea how to get a complete datasheet ?

Yeah, more register info at [1].
I've checked the detailed review below,
but I'll hold off on sending v2 until you decide if we really need a new driver.

Is this chip more like the LM63, by the way?

Quoted 4 lines

Good catch. Yes, looks like you are correct. LM63 is an almost perfect match. CTF2301 has a couple of extra registers, mostly local setpoint and temp LSB plus the registers in the 0x3x range. Actually, those registers _are_ defined for LM96163, so that chip is an even closer match.

Yes, so just to confirm,
you agree that the development should be done on top of the lm63 driver, right?