[PATCH v2 0/3] hwmon: add Microchip EMC2101 driver

[PATCH v2 0/3] hwmon: add Microchip EMC2101 driver

[Álvaro Fernández Rojas]

The Microchip EMC2101 is a SMBus 2.0 fan controller with temperature
monitoring.

It supports up to 1 fan, 1 internal temperature sensor, 1 external
temperature sensor and an 8 entry look up table to create a
programmable temperature response.

v2: multiple improvements:
 - add emc2101.rst to index.rst.
 - add missing documentation properties.
  - Remove FAN_RPM_MIN definition.
  - Rename FAN_FALSE_READ to FAN_MIN_READ.
  - pwm_auto_point_temp_hyst_store(): simplify function.
  - emc2101_fan_min_read(): add missing FAN_MIN_READ condition.
  - emc2101_fan_min_write(): fix tach_count calculation.
  - emc2101_init(): fix REG_TACH_MIN value.

Álvaro Fernández Rojas (3):
  docs: hwmon: add emc2101.rst to docs
  dt-bindings: hwmon: Add Microchip EMC2101 support
  drivers: hwmon: add EMC2101 driver

 .../bindings/hwmon/microchip,emc2101.yaml     |   79 +
 Documentation/hwmon/emc2101.rst               |   61 +
 Documentation/hwmon/index.rst                 |    1 +
 drivers/hwmon/Kconfig                         |   10 +
 drivers/hwmon/Makefile                        |    1 +
 drivers/hwmon/emc2101.c                       | 2175 +++++++++++++++++
 6 files changed, 2327 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/microchip,emc2101.yaml
 create mode 100644 Documentation/hwmon/emc2101.rst
 create mode 100644 drivers/hwmon/emc2101.c

-- 
2.39.5

[PATCH v2 1/3] docs: hwmon: add emc2101.rst to docs

[Álvaro Fernández Rojas]

Add description of emc2101 driver.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
 Documentation/hwmon/emc2101.rst | 61 +++++++++++++++++++++++++++++++++
 Documentation/hwmon/index.rst   |  1 +
 2 files changed, 62 insertions(+)
 create mode 100644 Documentation/hwmon/emc2101.rst

 v2: add emc2101 to index.rst

diff --git a/Documentation/hwmon/emc2101.rst b/Documentation/hwmon/emc2101.rst
new file mode 100644
index 000000000000..94db8a05a7a8
--- /dev/null
+++ b/Documentation/hwmon/emc2101.rst
@@ -0,0 +1,61 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver emc2101
+=====================
+
+Supported chips:
+   Microchip EMC2101, EMC2101-R
+
+   Addresses scanned: I2C 0x4c
+
+   Prefixes: 'emc2101', emc2101-r'
+
+   Datasheet: Publicly available at the Microchip website :
+      https://www.microchip.com/en-us/product/EMC2101
+
+Description:
+------------
+This driver implements support for Microchip EMC2101 RPM-based PWM Fan Controller.
+The EMC2101 Fan Controller supports up to 1 controlled PWM fan based on an
+external temperature diode.
+Fan rotation speed is reported in RPM.
+The driver supports the eight entries temperature look up table to automatically
+adjust the fan speed.
+
+The driver provides the following sysfs interfaces in hwmon subsystem:
+
+========================= == ===================================================
+fan1_div                  RW file for fan target duty cycle divider (0..255)
+fan1_input                RO file for TACH1 input (in RPM)
+fan1_min                  RW file for TACH1 min RPM
+fan1_min_alarm            RO file for TACH1 min RPM alarm indication
+fan1_spin_up_abort        RW file for fan spin up abort on low RPM
+fan1_spin_up_power        RW file for fan spin up power (in percentage)
+fan1_spin_up_time         RW file for fan spin up time (in ms)
+fan1_standby              RW file for fan standby mode
+pwm1                      RW file for fan target duty cycle (0..63)
+pwm1_auto_channels_temp   RW file for fan temperature sensor (external, force)
+pwm1_auto_point[1-8]_pwm  RW files for look up table fan speed
+pwm1_auto_point[1-8]_temp RW files for look up table temperature
+pwm1_auto_point_temp_hyst RW file for look up table temperature hysteresis
+pwm1_enable               RW file for fan config (manual, look up table)
+pwm1_freq                 RW file for fan target frequency
+pwm1_mode                 RW file for pwm mode (DAC, PWM)
+pwm1_polarity_invert      RW file for fan polarity inversion
+temp[1-3]_label           RO files for temperature labels
+temp1_input               RO file for internal temperature
+temp1_max                 RW file for max internal temperature
+temp1_max_alarm           RO file for max internal temperature alarm indication
+temp2_crit                RW file for crit external temperature
+temp2_crit_alarm          RO file for crit external temperature alarm indication
+temp2_crit_hyst           RW file for crit external temperature hysteresis
+temp2_fault               RO file for external temperature failure indication
+temp2_input               RO file for external temperature
+temp2_max                 RW file for max external temperature
+temp2_max_alarm           RO file for max external temperature alarm indication
+temp2_min                 RW file for min external temperature
+temp2_min_alarm           RO file for min external temperature alarm indication
+temp2_type                RW file for external temperature type (CPU, 2N3904)
+temp3                     RW file for forced temperature
+update_interval           RW file for temperature sensor update interval
+========================= == ===================================================
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index b45bfb4ebf30..c068462764d0 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -69,6 +69,7 @@ Hardware Monitoring Kernel Drivers
    ds1621
    ds620
    emc1403
+   emc2101
    emc2103
    emc2305
    emc6w201
-- 
2.39.5

[PATCH v2 2/3] dt-bindings: hwmon: Add Microchip EMC2101 support

[Álvaro Fernández Rojas]

Introduce yaml schema for Microchip emc2101 pwm fan controller with
temperature monitoring.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
 .../bindings/hwmon/microchip,emc2101.yaml     | 79 +++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/microchip,emc2101.yaml

 v2: add missing properties.

diff --git a/Documentation/devicetree/bindings/hwmon/microchip,emc2101.yaml b/Documentation/devicetree/bindings/hwmon/microchip,emc2101.yaml
new file mode 100644
index 000000000000..0966559d373e
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/microchip,emc2101.yaml
@@ -0,0 +1,79 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/microchip,emc2101.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip EMC2101 SMBus compliant PWM fan controller
+
+maintainers:
+  - Álvaro Fernández Rojas <noltari@gmail.com>
+
+description:
+  Microchip EMC2101 pwm controller which supports up to 1 fan, 1 internal
+  temperature sensor, 1 external temperature sensor and an 8 entry look
+  up table to create a programmable temperature response.
+
+properties:
+  compatible:
+    enum:
+      - microchip,emc2101
+      - microchip,emc2101-r
+
+  reg:
+    maxItems: 1
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+  '#pwm-cells':
+    const: 2
+    description: |
+      Number of cells in a PWM specifier.
+      - cell 0: The PWM frequency
+      - cell 1: The PWM polarity: 0 or PWM_POLARITY_INVERTED
+
+patternProperties:
+  '^fan@0$':
+    $ref: fan-common.yaml#
+    unevaluatedProperties: false
+    properties:
+      reg:
+        description:
+          The fan number used to determine the associated PWM channel.
+        maxItems: 1
+
+    required:
+      - reg
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        fan_controller: fan-controller@4c {
+            compatible = "microchip,emc2101";
+            reg = <0x4c>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+            #pwm-cells = <2>;
+
+            fan@0 {
+                reg = <0x0>;
+                pwms = <&fan_controller 5806 0>;
+                #cooling-cells = <2>;
+            };
+        };
+    };
+...
-- 
2.39.5

[PATCH] drivers: hwmon: add EMC2101 driver

[Álvaro Fernández Rojas]

The Microchip EMC2101 is a SMBus 2.0 fan controller with temperature
monitoring.
It supports up to 1 fan, 1 internal temperature sensor, 1 external
temperature sensor and an 8 entry look up table to create a
programmable temperature response.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
 drivers/hwmon/Kconfig   |   10 +
 drivers/hwmon/Makefile  |    1 +
 drivers/hwmon/emc2101.c | 2175 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 2186 insertions(+)
 create mode 100644 drivers/hwmon/emc2101.c

 v2: multiple improvements:
  - Remove FAN_RPM_MIN definition.
  - Rename FAN_FALSE_READ to FAN_MIN_READ.
  - pwm_auto_point_temp_hyst_store(): simplify function.
  - emc2101_fan_min_read(): add missing FAN_MIN_READ condition.
  - emc2101_fan_min_write(): fix tach_count calculation.
  - emc2101_init(): fix REG_TACH_MIN value.

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 079620dd4286..360b9f66275c 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2002,6 +2002,16 @@ config SENSORS_EMC1403
 	  Threshold values can be configured using sysfs.
 	  Data from the different diodes are accessible via sysfs.
 
+config SENSORS_EMC2101
+	tristate "SMSC EMC2101"
+	depends on I2C
+	help
+	  If you say yes here you get support for the SMSC EMC2101
+	  fan controller chips.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called emc2101.
+
 config SENSORS_EMC2103
 	tristate "SMSC EMC2103"
 	depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 48e5866c0c9a..70e95096c6f2 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -73,6 +73,7 @@ obj-$(CONFIG_SENSORS_DRIVETEMP)	+= drivetemp.o
 obj-$(CONFIG_SENSORS_DS620)	+= ds620.o
 obj-$(CONFIG_SENSORS_DS1621)	+= ds1621.o
 obj-$(CONFIG_SENSORS_EMC1403)	+= emc1403.o
+obj-$(CONFIG_SENSORS_EMC2101)	+= emc2101.o
 obj-$(CONFIG_SENSORS_EMC2103)	+= emc2103.o
 obj-$(CONFIG_SENSORS_EMC2305)	+= emc2305.o
 obj-$(CONFIG_SENSORS_EMC6W201)	+= emc6w201.o
diff --git a/drivers/hwmon/emc2101.c b/drivers/hwmon/emc2101.c
new file mode 100644
index 000000000000..65f2eff27aaf
--- /dev/null
+++ b/drivers/hwmon/emc2101.c
@@ -0,0 +1,2176 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Microchip EMC2101 fan controller.
+ *
+ * Copyright 2025 Álvaro Fernández Rojas <noltari@gmail.com>
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/util_macros.h>
+
+#define REG_TEMP_INT			0x00
+#define REG_TEMP_EXT_HI			0x01
+#define REG_STATUS			0x02
+#define  ADC_BUSY			BIT(7)
+#define  TEMP_INT_HIGH			BIT(6)
+#define  EEPROM_ERROR			BIT(5)
+#define  TEMP_EXT_HIGH			BIT(4)
+#define  TEMP_EXT_LOW			BIT(3)
+#define  TEMP_EXT_FAULT			BIT(2)
+#define  TEMP_EXT_CRIT			BIT(1)
+#define  TACH_LOW			BIT(0)
+#define REG_CONFIG			0x03
+#define  ALERT_IRQ_ACK			BIT(7)
+#define  FAN_STANDBY_ENABLE		BIT(6)
+#define  FAN_STANDBY_MODE		BIT(5)
+#define  FAN_MODE_DAC			BIT(4)
+#define  SMBUS_TOUT_DISABLE		BIT(3)
+#define  PIN_FUNC_TACH			BIT(2)
+#define  TEMP_EXT_CRIT_UNLOCK		BIT(1)
+#define  PIN_ASSERT_3_EXC		BIT(0)
+#define REG_CONV_RATE			0x04
+#define  CONV_RATE_MASK			0xf
+#define REG_TEMP_INT_MAX		0x05
+#define REG_TEMP_EXT_MAX_HI		0x07
+#define REG_TEMP_EXT_MIN_HI		0x08
+#define REG_TEMP_EXT_FORCE		0x0c
+#define REG_ONE_SHOT			0x0f
+#define REG_TEMP_EXT_LO			0x10
+#define REG_SCRATCHPAD_1		0x11
+#define REG_SCRATCHPAD_2		0x12
+#define REG_TEMP_EXT_MAX_LO		0x13
+#define REG_TEMP_EXT_MIN_LO		0x14
+#define REG_ALERT_MASK			0x16
+#define  IRQ_TEMP_INT_MAX_DISABLE	BIT(6)
+#define  IRQ_TEMP_EXT_MAX_DISABLE	BIT(4)
+#define  IRQ_TEMP_EXT_MIN_DISABLE	BIT(3)
+#define  IRQ_TEMP_EXT_CRIT_DISABLE	BIT(1)
+#define  IRQ_TACH_MIN_DISABLE		BIT(0)
+#define REG_EXT_IDEALITY		0x17
+#define  EXT_IDEALITY_START		9846
+#define  EXT_IDEALITY_STEP		13
+#define  EXT_IDEALITY_VAL(x)		(EXT_IDEALITY_START + \
+					 ((x) * EXT_IDEALITY_STEP))
+#define  EXT_IDEALITY_MASK		0x3f
+#define REG_BETA_COMP			0x18
+#define  BETA_COMP_AUTO			BIT(3)
+#define  BETA_COMP_DISABLE		7
+#define  BETA_COMP_2_33			6
+#define  BETA_COMP_1_00			5
+#define  BETA_COMP_0_43			4
+#define  BETA_COMP_0_33			3
+#define  BETA_COMP_0_25			2
+#define  BETA_COMP_0_18			1
+#define  BETA_COMP_0_11			0
+#define  BETA_COMP_MASK			0x7
+#define REG_TEMP_EXT_CRIT		0x19
+#define REG_TEMP_EXT_CRIT_HYST		0x21
+#define REG_TACH_LO			0x46
+#define REG_TACH_HI			0x47
+#define REG_TACH_MIN_LO			0x48
+#define REG_TACH_MIN_HI			0x49
+#define REG_FAN_CONFIG			0x4a
+#define  FAN_EXT_TEMP_FORCE		BIT(6)
+#define  FAN_LUT_DISABLE		BIT(5)
+#define  FAN_POL_INV			BIT(4)
+#define  FAN_CLK_SEL			BIT(3)
+#define  FAN_CLK_OVR			BIT(2)
+#define  TACH_FALSE_READ_DISABLE	BIT(0)
+#define  TACH_FALSE_READ_MASK		0x3
+#define REG_FAN_SPIN			0x4b
+#define  FAN_SPIN_UP_ABORT		BIT(5)
+#define  FAN_SPIN_UP_POWER_SHIFT	3
+#define  FAN_SPIN_UP_POWER_100		(3 << FAN_SPIN_UP_POWER_SHIFT)
+#define  FAN_SPIN_UP_POWER_75		(2 << FAN_SPIN_UP_POWER_SHIFT)
+#define  FAN_SPIN_UP_POWER_50		(1 << FAN_SPIN_UP_POWER_SHIFT)
+#define  FAN_SPIN_UP_POWER_0		(0 << FAN_SPIN_UP_POWER_SHIFT)
+#define  FAN_SPIN_UP_POWER_MASK		(0x3 << FAN_SPIN_UP_POWER_SHIFT)
+#define  FAN_SPIN_UP_TIME_3200		7
+#define  FAN_SPIN_UP_TIME_1600		6
+#define  FAN_SPIN_UP_TIME_800		5
+#define  FAN_SPIN_UP_TIME_400		4
+#define  FAN_SPIN_UP_TIME_200		3
+#define  FAN_SPIN_UP_TIME_100		2
+#define  FAN_SPIN_UP_TIME_50		1
+#define  FAN_SPIN_UP_TIME_0		0
+#define  FAN_SPIN_UP_TIME_MASK		0x7
+#define REG_FAN_SET			0x4c
+#define  FAN_SET_MASK			0x3f
+#define REG_PWM_FREQ			0x4d
+#define  PWM_FREQ_MASK			0x1f
+#define REG_PWM_FREQ_DIV		0x4e
+#define REG_FAN_LUT_HYST		0x4f
+#define  FAN_LUT_HYST_MASK		0x1f
+#define REG_FAN_LUT_TEMP(x)		(0x50 + (0x2 * (x)))
+/* Write only with FAN_LUT_DISABLE */
+#define  FAN_LUT_TEMP_MASK		0x7f
+#define REG_FAN_LUT_SPEED(x)		(0x51 + (0x2 * (x)))
+/* Write only with FAN_LUT_DISABLE */
+#define  FAN_LUT_SPEED_MASK		0x3f
+#define REG_AVG_FILTER			0xbf
+#define  FILTER_SHIFT			1
+#define  FILTER_L2			(3 << FILTER_SHIFT)
+#define  FILTER_L1			(1 << FILTER_SHIFT)
+#define  FILTER_NONE			(0 << FILTER_SHIFT)
+#define  FILTER_MASK			(0x3 << FILTER_SHIFT)
+#define  ALERT_PIN_TEMP_COMP		BIT(0)
+#define REG_PRODUCT_ID			0xfd
+#define REG_MANUFACTURER_ID		0xfe
+#define REG_REVISION			0xff
+
+#define CLK_FREQ_ALT			1400
+#define CLK_FREQ_BASE			360000
+
+#define FAN_LUT_COUNT			8
+#define FAN_LUT_HYST_DEF		4
+#define FAN_LUT_HYST_MIN		0
+#define FAN_LUT_HYST_MAX		31
+#define FAN_MIN_READ			0xffff
+#define FAN_RPM_FACTOR			5400000
+
+#define MANUFACTURER_ID			0x5d
+
+#define TEMP_EXT_HI_FAULT		0x7f
+#define TEMP_EXT_LO_FAULT_OPEN		0x00
+#define TEMP_EXT_LO_FAULT_SHORT		0xe0
+
+#define TEMP_LO_FRAC			125
+#define TEMP_LO_SHIFT			5
+#define TEMP_LO_MASK			(0x3 << TEMP_LO_SHIFT)
+
+#define TEMP_MIN			-64
+#define TEMP_MAX			127
+#define TEMP_MAX_FRAC			750
+
+enum emc2101_fan_spin_up_abort {
+	EMC2101_FAN_SPIN_ABORT_DISABLE = 0,
+	EMC2101_FAN_SPIN_ABORT_ENABLE
+};
+
+enum emc2101_fan_standby {
+	EMC2101_FAN_STBY_DISABLE = 0,
+	EMC2101_FAN_STBY_ENABLE
+};
+
+enum emc2101_mode {
+	EMC2101_MODE_PWM = 0,
+	EMC2101_MODE_DAC
+};
+
+enum ecm2101_product_id {
+	EMC2101 = 0x16,
+	EMC2101_R = 0x28
+};
+
+enum emc2101_pwm_enable {
+	EMC2101_PWM_MANUAL = 1,
+	EMC2101_PWM_LUT = 2
+};
+
+enum emc2101_pwm_polarity {
+	EMC2101_POL_NORMAL = 0,
+	EMC2101_POL_INVERTED
+};
+
+enum emc2101_temp_channels {
+	EMC2101_TC_INT = 0,
+	EMC2101_TC_EXT,
+	EMC2101_TC_FORCE,
+	EMC2101_TC_NUM
+};
+
+enum emc2101_temp_diode {
+	EMC2101_TD_CPU = 1,
+	EMC2101_TD_2N3904 = 2
+};
+
+struct emc2101_data {
+	struct i2c_client *client;
+	struct device *dev;
+	struct mutex mutex;
+};
+
+static const u16 emc2101_conv_time[] = {
+	62, 125, 250, 500, 1000, 2000, 4000, 8000, 16000, 32000
+};
+
+static const u8 emc2101_fan_spin_up_power[] = {
+	0, 50, 75, 100
+};
+
+static const u16 emc2101_fan_spin_up_time[] = {
+	0, 50, 100, 200, 400, 800, 1600, 3200
+};
+
+static inline int emc2101_read_u8(struct emc2101_data *data, u8 reg, u8 *val)
+{
+	struct i2c_client *client = data->client;
+	struct device *dev = data->dev;
+	s32 read_byte;
+	int ret;
+
+	read_byte = i2c_smbus_read_byte_data(client, reg);
+	if (read_byte < 0) {
+		ret = read_byte;
+		dev_err(dev, "error reading reg=%x err=%d", reg, read_byte);
+	} else {
+		ret = 0;
+		*val = read_byte;
+	}
+
+	return ret;
+}
+
+static inline int emc2101_read_u16(struct emc2101_data *data, u8 reg_hi, u8 reg_lo, u16 *val)
+{
+	u8 val_hi, val_lo;
+	int ret;
+
+	ret = emc2101_read_u8(data, reg_lo, &val_lo);
+	if (ret)
+		return ret;
+
+	ret = emc2101_read_u8(data, reg_hi, &val_hi);
+	if (ret)
+		return ret;
+
+	*val = (val_hi) << 8;
+	*val |= val_lo;
+
+	return ret;
+}
+
+static inline int emc2101_write_u8(struct emc2101_data *data, u8 reg, u8 val)
+{
+	struct i2c_client *client = data->client;
+	struct device *dev = data->dev;
+	s32 write_byte;
+
+	write_byte = i2c_smbus_write_byte_data(client, reg, val);
+	if (write_byte < 0)
+		dev_err(dev, "error writing reg=%x err=%d", reg, write_byte);
+
+	return write_byte;
+}
+
+static inline int emc2101_write_u16(struct emc2101_data *data, u8 reg_hi, u8 reg_lo, u16 val)
+{
+	const u8 val_hi = (val >> 8) & 0xff;
+	const u8 val_lo = val & 0xff;
+	int ret;
+
+	ret = emc2101_write_u8(data, reg_lo, val_lo);
+	if (ret)
+		return ret;
+
+	return emc2101_write_u8(data, reg_hi, val_hi);
+}
+
+static inline int emc2101_rmw_u8(struct emc2101_data *data, u8 reg, u8 clr, u8 set)
+{
+	int ret;
+	u8 val;
+
+	ret = emc2101_read_u8(data, reg, &val);
+	if (ret)
+		return ret;
+
+	val &= ~clr;
+	val |= set;
+
+	return emc2101_write_u8(data, reg, val);
+}
+
+static inline int emc2101_check_u8(struct emc2101_data *data, u8 reg, u8 mask, bool *val)
+{
+	u8 reg_val;
+	int ret;
+
+	ret = emc2101_read_u8(data, reg, &reg_val);
+	if (!ret)
+		*val = (reg_val & mask) == mask;
+
+	return ret;
+}
+
+static int emc2101_lut_hyst_write(struct emc2101_data *data, u8 reg, long temp)
+{
+	const u8 val = clamp_val(temp / 1000, FAN_LUT_HYST_MIN, FAN_LUT_HYST_MAX);
+
+	return emc2101_write_u8(data, reg, val);
+}
+
+static int emc2101_temp_read(struct emc2101_data *data, u8 reg, long *temp)
+{
+	int ret;
+	u8 val;
+
+	ret = emc2101_read_u8(data, reg, &val);
+	if (!ret)
+		*temp = val * 1000;
+
+	return ret;
+}
+
+static int emc2101_temp_neg_write(struct emc2101_data *data, u8 reg, long temp)
+{
+	const u8 val = clamp_val(temp / 1000, TEMP_MIN, TEMP_MAX);
+
+	return emc2101_write_u8(data, reg, val);
+}
+
+static int emc2101_temp_pos_write(struct emc2101_data *data, u8 reg, long temp)
+{
+	const u8 val = clamp_val(temp / 1000, 0, TEMP_MAX);
+
+	return emc2101_write_u8(data, reg, val);
+}
+
+static int emc2101_temp_frac_read(struct emc2101_data *data, u8 reg_hi, u8 reg_lo, long *temp)
+{
+	u8 val_hi, val_lo;
+	int ret;
+
+	ret = emc2101_read_u8(data, reg_hi, &val_hi);
+	if (ret)
+		return ret;
+
+	ret = emc2101_read_u8(data, reg_lo, &val_lo);
+	if (ret)
+		return ret;
+
+	val_lo &= TEMP_LO_MASK;
+
+	if (val_hi == TEMP_EXT_HI_FAULT) {
+		switch (val_lo) {
+		case TEMP_EXT_LO_FAULT_OPEN:
+			ret = -ENODATA;
+			dev_warn(data->dev, "[%02x, %02x]: diode fault (open)", reg_hi, reg_lo);
+			break;
+		case TEMP_EXT_LO_FAULT_SHORT:
+			ret = -ENODATA;
+			dev_warn(data->dev, "[%02x, %02x]: diode fault (short)", reg_hi, reg_lo);
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (!ret) {
+		*temp = val_lo >> TEMP_LO_SHIFT;
+		*temp *= TEMP_LO_FRAC;
+		*temp += val_hi * 1000;
+	}
+
+	return ret;
+}
+
+static int emc2101_temp_frac_write(struct emc2101_data *data, u8 reg_hi, u8 reg_lo, long temp)
+{
+	const u8 val_hi = clamp_val(temp / 1000, TEMP_MIN, TEMP_MAX);
+	long fraction = temp - (val_hi * 1000);
+	u8 val_lo;
+	int ret;
+
+	if (val_hi == TEMP_MAX && fraction > TEMP_MAX_FRAC)
+		fraction = clamp_val(fraction, 0, TEMP_MAX_FRAC);
+	fraction /= TEMP_LO_FRAC;
+	val_lo = (fraction << TEMP_LO_SHIFT) & TEMP_LO_MASK;
+
+	ret = emc2101_write_u8(data, reg_hi, val_hi);
+	if (ret)
+		return ret;
+
+	return emc2101_write_u8(data, reg_lo, val_lo);
+}
+
+static int emc2101_pwm_read(struct emc2101_data *data, u8 reg, long *pwm)
+{
+	int ret;
+	u8 val;
+
+	ret = emc2101_read_u8(data, reg, &val);
+	if (!ret)
+		*pwm = val;
+
+	return ret;
+}
+
+static int emc2101_pwm_write(struct emc2101_data *data, u8 reg, long pwm)
+{
+	const u8 val = clamp_val(pwm, 1, PWM_FREQ_MASK);
+
+	return emc2101_write_u8(data, reg, val);
+}
+
+static ssize_t fan_spin_up_abort_show(struct device *dev, struct device_attribute *devattr,
+				      char *buf)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool spin_abort_enabled;
+	u8 fan_spin_abort;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_check_u8(data, REG_FAN_SPIN, FAN_SPIN_UP_ABORT, &spin_abort_enabled);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	if (spin_abort_enabled)
+		fan_spin_abort = EMC2101_FAN_SPIN_ABORT_ENABLE;
+	else
+		fan_spin_abort = EMC2101_FAN_SPIN_ABORT_DISABLE;
+
+	return sprintf(buf, "%u\n", fan_spin_abort);
+}
+
+static ssize_t fan_spin_up_abort_store(struct device *dev, struct device_attribute *devattr,
+				       const char *buf, size_t count)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	long fan_spin_abort;
+	u8 clr, set;
+	int ret;
+
+	ret = kstrtol(buf, 10, &fan_spin_abort);
+	if (ret)
+		return ret;
+
+	switch (fan_spin_abort) {
+	case EMC2101_FAN_SPIN_ABORT_DISABLE:
+		clr = FAN_SPIN_UP_ABORT;
+		set = 0;
+		break;
+	case EMC2101_FAN_SPIN_ABORT_ENABLE:
+		clr = 0;
+		set = FAN_SPIN_UP_ABORT;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_rmw_u8(data, REG_FAN_SPIN, clr, set);
+	mutex_unlock(&data->mutex);
+
+	return !ret ? count : ret;
+}
+
+static ssize_t fan_spin_up_time_show(struct device *dev, struct device_attribute *devattr,
+				     char *buf)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u16 fan_spin_time;
+	u8 fan_spin;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_read_u8(data, REG_FAN_SPIN, &fan_spin);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	fan_spin_time = emc2101_fan_spin_up_time[fan_spin & FAN_SPIN_UP_TIME_MASK];
+
+	return sprintf(buf, "%u\n", fan_spin_time);
+}
+
+static ssize_t fan_spin_up_time_store(struct device *dev, struct device_attribute *devattr,
+				      const char *buf, size_t count)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u16 fan_spin_time_idx;
+	long fan_spin_time;
+	int ret;
+
+	ret = kstrtol(buf, 10, &fan_spin_time);
+	if (ret)
+		return ret;
+
+	fan_spin_time_idx = find_closest(fan_spin_time, emc2101_fan_spin_up_time,
+					 ARRAY_SIZE(emc2101_fan_spin_up_time));
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_rmw_u8(data, REG_FAN_SPIN, FAN_SPIN_UP_TIME_MASK, fan_spin_time_idx);
+	mutex_unlock(&data->mutex);
+
+	return !ret ? count : ret;
+}
+
+static ssize_t fan_spin_up_power_show(struct device *dev, struct device_attribute *devattr,
+				      char *buf)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 fan_spin_power;
+	u8 fan_spin;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_read_u8(data, REG_FAN_SPIN, &fan_spin);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	fan_spin_power = emc2101_fan_spin_up_power[(fan_spin & FAN_SPIN_UP_POWER_MASK) >>
+						   FAN_SPIN_UP_POWER_SHIFT];
+
+	return sprintf(buf, "%u\n", fan_spin_power);
+}
+
+static ssize_t fan_spin_up_power_store(struct device *dev, struct device_attribute *devattr,
+				       const char *buf, size_t count)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 fan_spin_power_idx;
+	long fan_spin_power;
+	int ret;
+
+	ret = kstrtol(buf, 10, &fan_spin_power);
+	if (ret)
+		return ret;
+
+	fan_spin_power_idx = find_closest(fan_spin_power, emc2101_fan_spin_up_power,
+					  ARRAY_SIZE(emc2101_fan_spin_up_power));
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_rmw_u8(data, REG_FAN_SPIN, FAN_SPIN_UP_POWER_MASK,
+			     fan_spin_power_idx << FAN_SPIN_UP_POWER_SHIFT);
+	mutex_unlock(&data->mutex);
+
+	return !ret ? count : ret;
+}
+
+static ssize_t fan_standby_show(struct device *dev, struct device_attribute *devattr,
+				char *buf)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool standby_enabled;
+	u8 fan_standby;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_check_u8(data, REG_CONFIG, FAN_STANDBY_ENABLE, &standby_enabled);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	if (standby_enabled)
+		fan_standby = EMC2101_FAN_STBY_ENABLE;
+	else
+		fan_standby = EMC2101_FAN_STBY_DISABLE;
+
+	return sprintf(buf, "%u\n", fan_standby);
+}
+
+static ssize_t fan_standby_store(struct device *dev, struct device_attribute *devattr,
+				 const char *buf, size_t count)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	long fan_standby;
+	u8 clr, set;
+	int ret;
+
+	ret = kstrtol(buf, 10, &fan_standby);
+	if (ret)
+		return ret;
+
+	switch (fan_standby) {
+	case EMC2101_FAN_STBY_DISABLE:
+		clr = FAN_STANDBY_ENABLE;
+		set = 0;
+		break;
+	case EMC2101_FAN_STBY_ENABLE:
+		clr = 0;
+		set = FAN_STANDBY_ENABLE;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_rmw_u8(data, REG_CONFIG, clr, set);
+	mutex_unlock(&data->mutex);
+
+	return !ret ? count : ret;
+}
+
+static ssize_t pwm_auto_point_pwm_show(struct device *dev, struct device_attribute *devattr,
+				       char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	const u8 reg = REG_FAN_LUT_SPEED(attr->index);
+	long lut_pwm;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_pwm_read(data, reg, &lut_pwm);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%lu\n", lut_pwm);
+}
+
+static ssize_t pwm_auto_point_pwm_store(struct device *dev, struct device_attribute *devattr,
+					const char *buf, size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	const u8 reg = REG_FAN_LUT_SPEED(attr->index);
+	long lut_pwm;
+	int ret;
+
+	ret = kstrtol(buf, 10, &lut_pwm);
+	if (ret)
+		return ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_pwm_write(data, reg, lut_pwm);
+	mutex_unlock(&data->mutex);
+
+	return !ret ? count : ret;
+}
+
+static ssize_t pwm_auto_point_temp_show(struct device *dev, struct device_attribute *devattr,
+					char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	const u8 reg = REG_FAN_LUT_TEMP(attr->index);
+	long lut_temp;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_read(data, reg, &lut_temp);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%lu\n", lut_temp);
+}
+
+static ssize_t __pwm_auto_point_temp_store(struct emc2101_data *data,
+					   struct device_attribute *devattr, const char *buf,
+					   size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	long cur_temp, lut_temp;
+	bool lut_disable;
+	unsigned int i;
+	int ret;
+
+	ret = kstrtol(buf, 10, &lut_temp);
+	if (ret)
+		return ret;
+
+	ret = emc2101_check_u8(data, REG_FAN_CONFIG, FAN_LUT_DISABLE, &lut_disable);
+	if (ret)
+		return ret;
+
+	if (!lut_disable) {
+		ret = emc2101_rmw_u8(data, REG_FAN_CONFIG, 0, FAN_LUT_DISABLE);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < FAN_LUT_COUNT; i++) {
+		const u8 reg = REG_FAN_LUT_TEMP(attr->index);
+
+		ret = emc2101_temp_read(data, reg, &cur_temp);
+		if (ret)
+			return ret;
+
+		if (i < attr->index) {
+			if (cur_temp > lut_temp)
+				ret = emc2101_temp_pos_write(data, reg, lut_temp);
+		} else if (i > attr->index) {
+			if (cur_temp < lut_temp)
+				ret = emc2101_temp_pos_write(data, reg, lut_temp);
+		} else {
+			ret = emc2101_temp_pos_write(data, reg, lut_temp);
+		}
+
+		if (ret)
+			return ret;
+	}
+
+	if (!lut_disable) {
+		ret = emc2101_rmw_u8(data, REG_FAN_CONFIG, FAN_LUT_DISABLE, 0);
+		if (ret)
+			return ret;
+	}
+
+	return !ret ? count : ret;
+}
+
+static ssize_t pwm_auto_point_temp_store(struct device *dev, struct device_attribute *devattr,
+					 const char *buf, size_t count)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = __pwm_auto_point_temp_store(data, devattr, buf, count);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static ssize_t pwm_auto_point_temp_hyst_show(struct device *dev, struct device_attribute *devattr,
+					     char *buf)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	long lut_hyst;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_read(data, REG_FAN_LUT_HYST, &lut_hyst);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%lu\n", lut_hyst);
+}
+
+static ssize_t pwm_auto_point_temp_hyst_store(struct device *dev, struct device_attribute *devattr,
+					      const char *buf, size_t count)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	long lut_hyst;
+	int ret;
+
+	ret = kstrtol(buf, 10, &lut_hyst);
+	if (ret)
+		return ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_lut_hyst_write(data, REG_FAN_LUT_HYST, lut_hyst);
+	mutex_unlock(&data->mutex);
+
+	return !ret ? count : ret;
+}
+
+static ssize_t pwm_polarity_invert_show(struct device *dev, struct device_attribute *devattr,
+					char *buf)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool polarity_inverted;
+	u8 polarity;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_check_u8(data, REG_FAN_CONFIG, FAN_POL_INV, &polarity_inverted);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	if (polarity_inverted)
+		polarity = EMC2101_POL_INVERTED;
+	else
+		polarity = EMC2101_POL_NORMAL;
+
+	return sprintf(buf, "%u\n", polarity);
+}
+
+static ssize_t pwm_polarity_invert_store(struct device *dev, struct device_attribute *devattr,
+					 const char *buf, size_t count)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	long polarity;
+	u8 clr, set;
+	int ret;
+
+	ret = kstrtol(buf, 10, &polarity);
+	if (ret)
+		return ret;
+
+	switch (polarity) {
+	case EMC2101_POL_INVERTED:
+		clr = 0;
+		set = FAN_POL_INV;
+		break;
+	case EMC2101_POL_NORMAL:
+		clr = FAN_POL_INV;
+		set = 0;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_rmw_u8(data, REG_FAN_CONFIG, clr, set);
+	mutex_unlock(&data->mutex);
+
+	return !ret ? count : ret;
+}
+
+static ssize_t temp_external_force_show(struct device *dev, struct device_attribute *devattr,
+					char *buf)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	long temp_force;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_read(data, REG_TEMP_EXT_FORCE, &temp_force);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%lu\n", temp_force);
+}
+
+static ssize_t temp_external_force_store(struct device *dev, struct device_attribute *devattr,
+					 const char *buf, size_t count)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	long temp_force;
+	int ret;
+
+	ret = kstrtol(buf, 10, &temp_force);
+	if (ret)
+		return ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_neg_write(data, REG_TEMP_EXT_FORCE, temp_force);
+	mutex_unlock(&data->mutex);
+
+	return !ret ? count : ret;
+}
+
+static ssize_t temp_external_ideality_show(struct device *dev, struct device_attribute *devattr,
+					   char *buf)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	long ext_ideality_factor;
+	u8 ext_ideality;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_read_u8(data, REG_EXT_IDEALITY, &ext_ideality);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	ext_ideality_factor = EXT_IDEALITY_VAL(ext_ideality);
+
+	return sprintf(buf, "%lu\n", ext_ideality_factor);
+}
+
+static ssize_t temp_external_ideality_store(struct device *dev, struct device_attribute *devattr,
+					    const char *buf, size_t count)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	long ext_ideality_factor;
+	u8 ext_ideality;
+	int ret;
+
+	ret = kstrtol(buf, 10, &ext_ideality_factor);
+	if (ret)
+		return ret;
+
+	ext_ideality_factor = clamp_val(ext_ideality_factor, EXT_IDEALITY_START,
+					EXT_IDEALITY_VAL(EXT_IDEALITY_MASK));
+	ext_ideality = (ext_ideality_factor - EXT_IDEALITY_START) / EXT_IDEALITY_STEP;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_write_u8(data, REG_EXT_IDEALITY, ext_ideality);
+	mutex_unlock(&data->mutex);
+
+	return !ret ? count : ret;
+}
+
+static SENSOR_DEVICE_ATTR_RW(fan1_spin_up_abort, fan_spin_up_abort, 0);
+static SENSOR_DEVICE_ATTR_RW(fan1_spin_up_power, fan_spin_up_power, 0);
+static SENSOR_DEVICE_ATTR_RW(fan1_spin_up_time, fan_spin_up_time, 0);
+static SENSOR_DEVICE_ATTR_RW(fan1_standby, fan_standby, 0);
+
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point1_pwm, pwm_auto_point_pwm, 0);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point1_temp, pwm_auto_point_temp, 0);
+
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point2_pwm, pwm_auto_point_pwm, 1);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point2_temp, pwm_auto_point_temp, 1);
+
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point3_pwm, pwm_auto_point_pwm, 2);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point3_temp, pwm_auto_point_temp, 2);
+
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point4_pwm, pwm_auto_point_pwm, 3);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point4_temp, pwm_auto_point_temp, 3);
+
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point5_pwm, pwm_auto_point_pwm, 4);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point5_temp, pwm_auto_point_temp, 4);
+
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point6_pwm, pwm_auto_point_pwm, 5);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point6_temp, pwm_auto_point_temp, 5);
+
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point7_pwm, pwm_auto_point_pwm, 6);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point7_temp, pwm_auto_point_temp, 6);
+
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point8_pwm, pwm_auto_point_pwm, 7);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point8_temp, pwm_auto_point_temp, 7);
+
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point_temp_hyst, pwm_auto_point_temp_hyst, 0);
+
+static SENSOR_DEVICE_ATTR_RW(pwm1_polarity_invert, pwm_polarity_invert, 0);
+
+static SENSOR_DEVICE_ATTR_RW(temp2_external_ideality, temp_external_ideality, 0);
+
+static SENSOR_DEVICE_ATTR_RW(temp3, temp_external_force, 0);
+
+static struct attribute *emc2101_hwmon_attributes[] = {
+	&sensor_dev_attr_fan1_spin_up_abort.dev_attr.attr,
+	&sensor_dev_attr_fan1_spin_up_power.dev_attr.attr,
+	&sensor_dev_attr_fan1_spin_up_time.dev_attr.attr,
+	&sensor_dev_attr_fan1_standby.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point1_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point1_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point2_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point2_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point3_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point3_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point4_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point4_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point5_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point5_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point6_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point6_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point7_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point7_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point8_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point8_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point_temp_hyst.dev_attr.attr,
+	&sensor_dev_attr_pwm1_polarity_invert.dev_attr.attr,
+	&sensor_dev_attr_temp2_external_ideality.dev_attr.attr,
+	&sensor_dev_attr_temp3.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group emc2101_hwmon_group = {
+	.attrs = emc2101_hwmon_attributes,
+};
+__ATTRIBUTE_GROUPS(emc2101_hwmon);
+
+static int emc2101_chip_update_interval_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 conv_rate;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_read_u8(data, REG_CONV_RATE, &conv_rate);
+	mutex_unlock(&data->mutex);
+
+	if (!ret) {
+		conv_rate &= CONV_RATE_MASK;
+		if (conv_rate < ARRAY_SIZE(emc2101_conv_time))
+			*val = emc2101_conv_time[conv_rate];
+		else
+			*val = 32000;
+	}
+
+	return ret;
+}
+
+static int emc2101_chip_update_interval_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 conv_rate;
+	int ret;
+
+	conv_rate = find_closest(val, emc2101_conv_time, ARRAY_SIZE(emc2101_conv_time));
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_write_u8(data, REG_CONV_RATE, conv_rate);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_fan_div_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 pwm_freq_div;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_read_u8(data, REG_PWM_FREQ_DIV, &pwm_freq_div);
+	mutex_unlock(&data->mutex);
+
+	if (!ret)
+		*val = pwm_freq_div;
+
+	return ret;
+}
+
+static int emc2101_fan_div_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 pwm_freq_div = val;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_write_u8(data, REG_PWM_FREQ_DIV, pwm_freq_div);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_fan_input_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u16 tach_count;
+	int ret;
+
+	ret = emc2101_read_u16(data, REG_TACH_HI, REG_TACH_LO, &tach_count);
+	if (ret)
+		return ret;
+
+	if (tach_count && tach_count != FAN_MIN_READ)
+		*val = FAN_RPM_FACTOR / tach_count;
+	else
+		*val = 0;
+
+	return ret;
+}
+
+static int emc2101_fan_min_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u16 tach_count;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_read_u16(data, REG_TACH_MIN_HI, REG_TACH_MIN_LO, &tach_count);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	if (tach_count && tach_count != FAN_MIN_READ)
+		*val = FAN_RPM_FACTOR / tach_count;
+	else
+		*val = 0;
+
+	return ret;
+}
+
+static int emc2101_fan_min_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u16 tach_count;
+	int ret;
+
+	if (val)
+		tach_count = clamp_val(FAN_RPM_FACTOR / val, 0, FAN_MIN_READ);
+	else
+		tach_count = FAN_MIN_READ;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_write_u16(data, REG_TACH_MIN_HI, REG_TACH_MIN_LO, tach_count);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_fan_min_alarm_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool tach_low;
+	int ret;
+
+	ret = emc2101_check_u8(data, REG_STATUS, TACH_LOW, &tach_low);
+	if (!ret)
+		*val = tach_low;
+
+	return ret;
+}
+
+static int emc2101_pwm_auto_channels_temp_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 fan_config;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_read_u8(data, REG_FAN_CONFIG, &fan_config);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	if (fan_config & FAN_EXT_TEMP_FORCE)
+		*val = 3;
+	else
+		*val = 2;
+
+	return ret;
+}
+
+static int emc2101_pwm_auto_channels_temp_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 clr, set;
+	int ret;
+
+	switch (val) {
+	case 2:
+		clr = FAN_EXT_TEMP_FORCE;
+		set = 0;
+		break;
+	case 3:
+		clr = 0;
+		set = FAN_EXT_TEMP_FORCE;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_rmw_u8(data, REG_FAN_CONFIG, clr, set);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_pwm_enable_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool lut_disable;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_check_u8(data, REG_FAN_CONFIG, FAN_LUT_DISABLE, &lut_disable);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	if (lut_disable)
+		*val = EMC2101_PWM_MANUAL;
+	else
+		*val = EMC2101_PWM_LUT;
+
+	return ret;
+}
+
+static int emc2101_pwm_enable_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 clr, set;
+	int ret;
+
+	switch (val) {
+	case EMC2101_PWM_MANUAL:
+		clr = 0;
+		set = FAN_LUT_DISABLE;
+		break;
+	case EMC2101_PWM_LUT:
+		clr = FAN_LUT_DISABLE;
+		set = 0;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_rmw_u8(data, REG_FAN_CONFIG, clr, set);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int __emc2101_pwm_freq_read(struct emc2101_data *data, long *val)
+{
+	u8 fan_config, pwm_freq, pwm_freq_div;
+	unsigned int base_clk, div;
+	int ret;
+
+	ret = emc2101_read_u8(data, REG_FAN_CONFIG, &fan_config);
+	if (ret)
+		return ret;
+
+	ret = emc2101_read_u8(data, REG_PWM_FREQ, &pwm_freq);
+	if (ret)
+		return ret;
+
+	if (fan_config & FAN_CLK_OVR) {
+		ret = emc2101_read_u8(data, REG_PWM_FREQ_DIV, &pwm_freq_div);
+		if (ret)
+			return ret;
+	} else {
+		pwm_freq_div = 1;
+	}
+
+	if (fan_config & FAN_CLK_SEL)
+		base_clk = CLK_FREQ_ALT;
+	else
+		base_clk = CLK_FREQ_BASE;
+
+	div = 2 * pwm_freq * pwm_freq_div;
+	if (div)
+		*val = base_clk / div;
+	else
+		*val = 0;
+
+	return ret;
+}
+
+static int emc2101_pwm_freq_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = __emc2101_pwm_freq_read(data, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int __emc2101_pwm_freq_write(struct emc2101_data *data, long val)
+{
+	u8 fan_config, pwm_freq, pwm_freq_div;
+	unsigned int base_clk;
+	int ret;
+
+	ret = emc2101_read_u8(data, REG_FAN_CONFIG, &fan_config);
+	if (ret)
+		return ret;
+
+	if (fan_config & FAN_CLK_OVR) {
+		ret = emc2101_read_u8(data, REG_PWM_FREQ_DIV, &pwm_freq_div);
+		if (ret)
+			return ret;
+	} else {
+		pwm_freq_div = 1;
+	}
+
+	if (fan_config & FAN_CLK_SEL)
+		base_clk = CLK_FREQ_ALT;
+	else
+		base_clk = CLK_FREQ_BASE;
+
+	pwm_freq = base_clk / (2 * pwm_freq_div * val);
+
+	return emc2101_pwm_write(data, REG_PWM_FREQ, pwm_freq);
+}
+
+static int emc2101_pwm_freq_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = __emc2101_pwm_freq_write(data, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_pwm_input_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 fan_set;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_read_u8(data, REG_FAN_SET, &fan_set);
+	mutex_unlock(&data->mutex);
+
+	if (!ret)
+		*val = fan_set;
+
+	return ret;
+}
+
+static int emc2101_pwm_input_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 fan_set = clamp_val(val, 0, FAN_SET_MASK);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_write_u8(data, REG_FAN_SET, fan_set);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_pwm_mode_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool mode_dac;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_check_u8(data, REG_CONFIG, FAN_MODE_DAC, &mode_dac);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	if (mode_dac)
+		*val = EMC2101_MODE_DAC;
+	else
+		*val = EMC2101_MODE_PWM;
+
+	return ret;
+}
+
+static int emc2101_pwm_mode_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 clr, set;
+	int ret;
+
+	switch (val) {
+	case EMC2101_MODE_DAC:
+		clr = 0;
+		set = FAN_MODE_DAC;
+		break;
+	case EMC2101_MODE_PWM:
+		clr = FAN_MODE_DAC;
+		set = 0;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_rmw_u8(data, REG_CONFIG, clr, set);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_temp_ext_crit_alarm_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool temp_crit;
+	int ret;
+
+	ret = emc2101_check_u8(data, REG_STATUS, TEMP_EXT_CRIT, &temp_crit);
+	if (!ret)
+		*val = temp_crit;
+
+	return ret;
+}
+
+static int emc2101_temp_ext_crit_hyst_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_read(data, REG_TEMP_EXT_CRIT_HYST, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_temp_ext_crit_hyst_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_pos_write(data, REG_TEMP_EXT_CRIT_HYST, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_temp_ext_crit_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_read(data, REG_TEMP_EXT_CRIT, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int __emc2101_temp_ext_crit_write(struct emc2101_data *data, long val)
+{
+	struct device *dev = data->dev;
+	bool temp_unlock;
+	int ret;
+
+	ret = emc2101_check_u8(data, REG_CONFIG, TEMP_EXT_CRIT_UNLOCK, &temp_unlock);
+	if (ret)
+		return ret;
+
+	if (temp_unlock) {
+		dev_err(dev, "critical temperature can only be updated once");
+		return -EIO;
+	}
+
+	ret = emc2101_rmw_u8(data, REG_CONFIG, 0, TEMP_EXT_CRIT_UNLOCK);
+	if (ret)
+		return ret;
+
+	return emc2101_temp_pos_write(data, REG_TEMP_EXT_CRIT, val);
+}
+
+static int emc2101_temp_ext_crit_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = __emc2101_temp_ext_crit_write(data, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_temp_ext_fault_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool temp_fault;
+	int ret;
+
+	ret = emc2101_check_u8(data, REG_STATUS, TEMP_EXT_FAULT, &temp_fault);
+	if (!ret)
+		*val = temp_fault;
+
+	return ret;
+}
+
+static int emc2101_temp_ext_max_alarm_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool temp_high;
+	int ret;
+
+	ret = emc2101_check_u8(data, REG_STATUS, TEMP_EXT_HIGH, &temp_high);
+	if (!ret)
+		*val = temp_high;
+
+	return ret;
+}
+
+static int emc2101_temp_ext_max_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_frac_read(data, REG_TEMP_EXT_MAX_HI, REG_TEMP_EXT_MAX_LO, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_temp_ext_max_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_frac_write(data, REG_TEMP_EXT_MAX_HI, REG_TEMP_EXT_MAX_LO, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_temp_ext_min_alarm_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool temp_low;
+	int ret;
+
+	ret = emc2101_check_u8(data, REG_STATUS, TEMP_EXT_LOW, &temp_low);
+	if (!ret)
+		*val = temp_low;
+
+	return ret;
+}
+
+static int emc2101_temp_ext_min_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_frac_read(data, REG_TEMP_EXT_MIN_HI, REG_TEMP_EXT_MIN_LO, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_temp_ext_min_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_frac_write(data, REG_TEMP_EXT_MIN_HI, REG_TEMP_EXT_MIN_LO, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_temp_ext_type_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool beta_comp_disable;
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_check_u8(data, REG_BETA_COMP, BETA_COMP_DISABLE, &beta_comp_disable);
+	mutex_unlock(&data->mutex);
+
+	if (ret)
+		return ret;
+
+	if (beta_comp_disable)
+		*val = EMC2101_TD_2N3904;
+	else
+		*val = EMC2101_TD_CPU;
+
+	return ret;
+}
+
+static int emc2101_temp_ext_type_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	u8 set, clr;
+	int ret;
+
+	switch (val) {
+	case EMC2101_TD_CPU:
+		clr = BETA_COMP_MASK;
+		set = BETA_COMP_AUTO;
+		break;
+	case EMC2101_TD_2N3904:
+		clr = BETA_COMP_AUTO | BETA_COMP_MASK;
+		set = BETA_COMP_DISABLE;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_rmw_u8(data, REG_BETA_COMP, clr, set);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_temp_ext_input_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+
+	return emc2101_temp_frac_read(data, REG_TEMP_EXT_HI, REG_TEMP_EXT_LO, val);
+}
+
+static int emc2101_temp_int_max_alarm_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	bool temp_high;
+	int ret;
+
+	ret = emc2101_check_u8(data, REG_STATUS, TEMP_INT_HIGH, &temp_high);
+	if (!ret)
+		*val = temp_high;
+
+	return ret;
+}
+
+static int emc2101_temp_int_max_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_read(data, REG_TEMP_INT_MAX, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_temp_int_max_write(struct device *dev, long val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = emc2101_temp_pos_write(data, REG_TEMP_INT_MAX, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int emc2101_temp_int_input_read(struct device *dev, long *val)
+{
+	struct emc2101_data *data = dev_get_drvdata(dev);
+
+	return emc2101_temp_read(data, REG_TEMP_INT, val);
+}
+
+static umode_t emc2101_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
+				  int channel)
+{
+	int max_channels;
+
+	if (type == hwmon_temp)
+		max_channels = EMC2101_TC_NUM;
+	else
+		max_channels = 1;
+
+	if (channel >= max_channels)
+		return 0;
+
+	switch (type) {
+	case hwmon_chip:
+		switch (attr) {
+		case hwmon_chip_update_interval:
+			return 0644;
+		default:
+			break;
+		}
+		break;
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+		case hwmon_fan_min_alarm:
+			return 0444;
+		case hwmon_fan_div:
+		case hwmon_fan_min:
+			return 0644;
+		default:
+			break;
+		}
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_auto_channels_temp:
+		case hwmon_pwm_enable:
+		case hwmon_pwm_freq:
+		case hwmon_pwm_input:
+		case hwmon_pwm_mode:
+			return 0644;
+		default:
+			break;
+		}
+		break;
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_crit_alarm:
+		case hwmon_temp_fault:
+		case hwmon_temp_input:
+		case hwmon_temp_label:
+		case hwmon_temp_max_alarm:
+		case hwmon_temp_min_alarm:
+			return 0444;
+		case hwmon_temp_crit:
+		case hwmon_temp_crit_hyst:
+		case hwmon_temp_max:
+		case hwmon_temp_min:
+		case hwmon_temp_type:
+			return 0644;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+};
+
+static int emc2101_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
+			long *val)
+{
+	switch (type) {
+	case hwmon_chip:
+		switch (attr) {
+		case hwmon_chip_update_interval:
+			return emc2101_chip_update_interval_read(dev, val);
+		default:
+			break;
+		}
+		break;
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_div:
+			return emc2101_fan_div_read(dev, val);
+		case hwmon_fan_input:
+			return emc2101_fan_input_read(dev, val);
+		case hwmon_fan_min:
+			return emc2101_fan_min_read(dev, val);
+		case hwmon_fan_min_alarm:
+			return emc2101_fan_min_alarm_read(dev, val);
+		default:
+			break;
+		}
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_auto_channels_temp:
+			return emc2101_pwm_auto_channels_temp_read(dev, val);
+		case hwmon_pwm_enable:
+			return emc2101_pwm_enable_read(dev, val);
+		case hwmon_pwm_freq:
+			return emc2101_pwm_freq_read(dev, val);
+		case hwmon_pwm_input:
+			return emc2101_pwm_input_read(dev, val);
+		case hwmon_pwm_mode:
+			return emc2101_pwm_mode_read(dev, val);
+		default:
+			break;
+		}
+		break;
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_crit:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_crit_read(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_crit_alarm:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_crit_alarm_read(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_crit_hyst:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_crit_hyst_read(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_fault:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_fault_read(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_input:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_input_read(dev, val);
+			case EMC2101_TC_INT:
+				return emc2101_temp_int_input_read(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_max:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_max_read(dev, val);
+			case EMC2101_TC_INT:
+				return emc2101_temp_int_max_read(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_max_alarm:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_max_alarm_read(dev, val);
+			case EMC2101_TC_INT:
+				return emc2101_temp_int_max_alarm_read(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_min:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_min_read(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_min_alarm:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_min_alarm_read(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_type:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_type_read(dev, val);
+			default:
+				break;
+			}
+			break;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+};
+
+static int emc2101_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+			       int channel, const char **str)
+{
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_label:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				*str = "external";
+				return 0;
+			case EMC2101_TC_FORCE:
+				*str = "force";
+				return 0;
+			case EMC2101_TC_INT:
+				*str = "internal";
+				return 0;
+			default:
+				break;
+			}
+			break;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+};
+
+static int emc2101_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
+			 long val)
+{
+	switch (type) {
+	case hwmon_chip:
+		switch (attr) {
+		case hwmon_chip_update_interval:
+			return emc2101_chip_update_interval_write(dev, val);
+		default:
+			break;
+		}
+		break;
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_div:
+			return emc2101_fan_div_write(dev, val);
+		case hwmon_fan_min:
+			return emc2101_fan_min_write(dev, val);
+		default:
+			break;
+		}
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_auto_channels_temp:
+			return emc2101_pwm_auto_channels_temp_write(dev, val);
+		case hwmon_pwm_enable:
+			return emc2101_pwm_enable_write(dev, val);
+		case hwmon_pwm_freq:
+			return emc2101_pwm_freq_write(dev, val);
+		case hwmon_pwm_input:
+			return emc2101_pwm_input_write(dev, val);
+		case hwmon_pwm_mode:
+			return emc2101_pwm_mode_write(dev, val);
+		default:
+			break;
+		}
+		break;
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_crit:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_crit_write(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_crit_hyst:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_crit_hyst_write(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_max:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_max_write(dev, val);
+			case EMC2101_TC_INT:
+				return emc2101_temp_int_max_write(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_min:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_min_write(dev, val);
+			default:
+				break;
+			}
+			break;
+		case hwmon_temp_type:
+			switch (channel) {
+			case EMC2101_TC_EXT:
+				return emc2101_temp_ext_type_write(dev, val);
+			default:
+				break;
+			}
+			break;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+#define EMC2101_CHIP_CFG	HWMON_C_UPDATE_INTERVAL
+#define EMC2101_FAN_CFG		(HWMON_F_DIV |\
+				 HWMON_F_INPUT |\
+				 HWMON_F_MIN |\
+				 HWMON_F_MIN_ALARM)
+#define EMC2101_PWM_CFG		(HWMON_PWM_AUTO_CHANNELS_TEMP |\
+				 HWMON_PWM_ENABLE |\
+				 HWMON_PWM_FREQ |\
+				 HWMON_PWM_INPUT |\
+				 HWMON_PWM_MODE)
+#define EMC2101_TEMP_INT_CFG	(HWMON_T_INPUT |\
+				 HWMON_T_LABEL |\
+				 HWMON_T_MAX |\
+				 HWMON_T_MAX_ALARM)
+#define EMC2101_TEMP_EXT_CFG	(HWMON_T_CRIT |\
+				 HWMON_T_CRIT_ALARM |\
+				 HWMON_T_CRIT_HYST |\
+				 HWMON_T_FAULT |\
+				 HWMON_T_INPUT |\
+				 HWMON_T_LABEL |\
+				 HWMON_T_MAX |\
+				 HWMON_T_MAX_ALARM |\
+				 HWMON_T_MIN |\
+				 HWMON_T_MIN_ALARM |\
+				 HWMON_T_TYPE)
+#define EMC2101_TEMP_FORCE_CFG	HWMON_T_LABEL
+
+static const struct hwmon_channel_info * const emc2101_info[] = {
+	HWMON_CHANNEL_INFO(chip, EMC2101_CHIP_CFG),
+	HWMON_CHANNEL_INFO(fan, EMC2101_FAN_CFG),
+	HWMON_CHANNEL_INFO(pwm, EMC2101_PWM_CFG),
+	HWMON_CHANNEL_INFO(temp, EMC2101_TEMP_INT_CFG,
+			   EMC2101_TEMP_EXT_CFG,
+			   EMC2101_TEMP_FORCE_CFG),
+	NULL
+};
+
+static const struct hwmon_ops emc2101_ops = {
+	.is_visible = emc2101_is_visible,
+	.read = emc2101_read,
+	.read_string = emc2101_read_string,
+	.write = emc2101_write,
+};
+
+static const struct hwmon_chip_info emc2101_chip_info = {
+	.info = emc2101_info,
+	.ops = &emc2101_ops,
+};
+
+static int emc2101_init(struct emc2101_data *data)
+{
+	static const u8 lut_t[FAN_LUT_COUNT] = {  35,   40,   45,   50,   55,   60,   70,   75};
+	static const u8 lut_s[FAN_LUT_COUNT] = {0x12, 0x19, 0x1f, 0x25, 0x2c, 0x32, 0x38, 0x3f};
+	unsigned int i;
+	int ret;
+
+	ret = emc2101_write_u8(data, REG_CONFIG,
+			       (FAN_STANDBY_MODE |
+				PIN_FUNC_TACH |
+				SMBUS_TOUT_DISABLE));
+
+	ret = emc2101_write_u8(data, REG_FAN_CONFIG,
+			       (FAN_CLK_OVR |
+				FAN_LUT_DISABLE |
+				TACH_FALSE_READ_DISABLE));
+	if (ret)
+		return ret;
+	for (i = 0; i < FAN_LUT_COUNT; i++) {
+		ret = emc2101_write_u8(data, REG_FAN_LUT_TEMP(i), lut_t[i]);
+		if (ret)
+			return ret;
+		ret = emc2101_write_u8(data, REG_FAN_LUT_SPEED(i), lut_s[i]);
+		if (ret)
+			return ret;
+	}
+	ret = emc2101_rmw_u8(data, REG_FAN_CONFIG, FAN_LUT_DISABLE, 0);
+	if (ret)
+		return ret;
+
+	ret = emc2101_write_u8(data, REG_FAN_SPIN,
+			       (FAN_SPIN_UP_POWER_100 |
+				FAN_SPIN_UP_ABORT |
+				FAN_SPIN_UP_TIME_3200));
+	if (ret)
+		return ret;
+
+	ret = emc2101_write_u8(data, REG_FAN_LUT_HYST, FAN_LUT_HYST_DEF);
+	if (ret)
+		return ret;
+
+	ret = emc2101_write_u8(data, REG_PWM_FREQ, PWM_FREQ_MASK);
+	if (ret)
+		return ret;
+
+	ret = emc2101_write_u8(data, REG_PWM_FREQ_DIV, 1);
+	if (ret)
+		return ret;
+
+	ret = emc2101_write_u8(data, REG_AVG_FILTER, FILTER_NONE);
+	if (ret)
+		return ret;
+
+	ret = emc2101_write_u16(data, REG_TACH_MIN_HI, REG_TACH_MIN_LO, FAN_MIN_READ);
+	if (ret)
+		return ret;
+
+	return emc2101_rmw_u8(data, REG_BETA_COMP, 0, BETA_COMP_DISABLE);
+}
+
+static int emc2101_probe(struct i2c_client *client)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct device *dev = &client->dev;
+	struct emc2101_data *data;
+	struct device *hwmon_dev;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -EIO;
+
+	data = devm_kzalloc(dev, sizeof(struct emc2101_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	data->dev = dev;
+	mutex_init(&data->mutex);
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
+							 &emc2101_chip_info,
+							 emc2101_hwmon_groups);
+	if (IS_ERR(hwmon_dev))
+		return PTR_ERR(hwmon_dev);
+
+	dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
+
+	return emc2101_init(data);
+}
+
+static int emc2101_detect(struct i2c_client *client, struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	s32 manufacturer, product, revision;
+	struct device *dev = &adapter->dev;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	manufacturer = i2c_smbus_read_byte_data(client, REG_MANUFACTURER_ID);
+	if (manufacturer != MANUFACTURER_ID)
+		return -ENODEV;
+
+	product = i2c_smbus_read_byte_data(client, REG_PRODUCT_ID);
+	switch (product) {
+	case EMC2101:
+		strscpy(info->type, "emc2101", I2C_NAME_SIZE);
+		break;
+	case EMC2101_R:
+		strscpy(info->type, "emc2101-r", I2C_NAME_SIZE);
+		break;
+	default:
+		return -ENODEV;
+	}
+
+	revision = i2c_smbus_read_byte_data(client, REG_REVISION);
+
+	dev_info(dev, "Found %s at 0x%02x (rev 0x%02x).\n",
+		 info->type, client->addr, revision);
+
+	return 0;
+}
+
+static const struct i2c_device_id emc2101_ids[] = {
+	{ "emc2101" },
+	{ "emc2101-r" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, emc2101_ids);
+
+static const struct of_device_id emc2101_of_match_table[] = {
+	{ .compatible = "microchip,emc2101", },
+	{ .compatible = "microchip,emc2101-r", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, emc2101_of_match_table);
+
+static const unsigned short emc2101_address_list[] = {
+	0x4c, I2C_CLIENT_END
+};
+
+static struct i2c_driver emc2101_driver = {
+	.address_list = emc2101_address_list,
+	.class = I2C_CLASS_HWMON,
+	.detect = emc2101_detect,
+	.driver = {
+		.name = "emc2101",
+		.of_match_table = emc2101_of_match_table,
+	},
+	.id_table = emc2101_ids,
+	.probe = emc2101_probe,
+};
+module_i2c_driver(emc2101_driver);
+
+MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
+MODULE_DESCRIPTION("Microchip EMC2101 hwmon driver");
+MODULE_LICENSE("GPL");
-- 
2.39.5

Re: [PATCH v2 2/3] dt-bindings: hwmon: Add Microchip EMC2101 support

[Rob Herring (Arm)]

On Tue, 01 Jul 2025 20:12:27 +0200, Álvaro Fernández Rojas wrote:
> Introduce yaml schema for Microchip emc2101 pwm fan controller with
> temperature monitoring.
> 
> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> ---
>  .../bindings/hwmon/microchip,emc2101.yaml     | 79 +++++++++++++++++++
>  1 file changed, 79 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/hwmon/microchip,emc2101.yaml
> 
>  v2: add missing properties.
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/hwmon/microchip,emc2101.yaml: patternProperties: '^fan@0$' should not be valid under {'pattern': '^\\^[a-zA-Z0-9,\\-._#@]+\\$$'}
	hint: Fixed strings belong in 'properties', not 'patternProperties'
	from schema $id: http://devicetree.org/meta-schemas/keywords.yaml#

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20250701181228.1196102-3-noltari@gmail.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

Re: [PATCH v2 2/3] dt-bindings: hwmon: Add Microchip EMC2101 support

[Krzysztof Kozlowski]

On Tue, Jul 01, 2025 at 08:12:27PM +0200, Álvaro Fernández Rojas wrote:
> Introduce yaml schema for Microchip emc2101 pwm fan controller with
> temperature monitoring.
> 
> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> ---
>  .../bindings/hwmon/microchip,emc2101.yaml     | 79 +++++++++++++++++++
>  1 file changed, 79 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/hwmon/microchip,emc2101.yaml
> 
>  v2: add missing properties.
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/microchip,emc2101.yaml b/Documentation/devicetree/bindings/hwmon/microchip,emc2101.yaml
> new file mode 100644
> index 000000000000..0966559d373e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/microchip,emc2101.yaml
> @@ -0,0 +1,79 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/hwmon/microchip,emc2101.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Microchip EMC2101 SMBus compliant PWM fan controller
> +
> +maintainers:
> +  - Álvaro Fernández Rojas <noltari@gmail.com>
> +
> +description:
> +  Microchip EMC2101 pwm controller which supports up to 1 fan, 1 internal
> +  temperature sensor, 1 external temperature sensor and an 8 entry look
> +  up table to create a programmable temperature response.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - microchip,emc2101
> +      - microchip,emc2101-r

Nothing in description explains what 'r' is.

> +
> +  reg:
> +    maxItems: 1
> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +  '#pwm-cells':
> +    const: 2
> +    description: |
> +      Number of cells in a PWM specifier.
> +      - cell 0: The PWM frequency
> +      - cell 1: The PWM polarity: 0 or PWM_POLARITY_INVERTED
> +
> +patternProperties:
> +  '^fan@0$':

This is just 'fan', not a pattern. See other bidnings.

> +    $ref: fan-common.yaml#
> +    unevaluatedProperties: false
> +    properties:
> +      reg:
> +        description:
> +          The fan number used to determine the associated PWM channel.

I can tell you: 0. Cannot be any other PWM channel.

> +        maxItems: 1
> +
> +    required:
> +      - reg
> +
> +required:
> +  - compatible
> +  - reg

Best regards,
Krzysztof

Re: [PATCH] drivers: hwmon: add EMC2101 driver

[Krzysztof Kozlowski]

On 01/07/2025 20:12, Álvaro Fernández Rojas wrote:
> The Microchip EMC2101 is a SMBus 2.0 fan controller with temperature
> monitoring.
> It supports up to 1 fan, 1 internal temperature sensor, 1 external
> temperature sensor and an 8 entry look up table to create a
> programmable temperature response.
> 
> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> ---
>  drivers/hwmon/Kconfig   |   10 +
>  drivers/hwmon/Makefile  |    1 +
>  drivers/hwmon/emc2101.c | 2175 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 2186 insertions(+)
>  create mode 100644 drivers/hwmon/emc2101.c
> 
>  v2: multiple improvements:
>   - Remove FAN_RPM_MIN definition.
>   - Rename FAN_FALSE_READ to FAN_MIN_READ.
>   - pwm_auto_point_temp_hyst_store(): simplify function.
>   - emc2101_fan_min_read(): add missing FAN_MIN_READ condition.
>   - emc2101_fan_min_write(): fix tach_count calculation.
>   - emc2101_init(): fix REG_TACH_MIN value.
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 079620dd4286..360b9f66275c 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -2002,6 +2002,16 @@ config SENSORS_EMC1403
>  	  Threshold values can be configured using sysfs.
>  	  Data from the different diodes are accessible via sysfs.
>  
> +config SENSORS_EMC2101
> +	tristate "SMSC EMC2101"
> +	depends on I2C
> +	help
> +	  If you say yes here you get support for the SMSC EMC2101
> +	  fan controller chips.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called emc2101.
> +
>  config SENSORS_EMC2103
>  	tristate "SMSC EMC2103"
>  	depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 48e5866c0c9a..70e95096c6f2 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -73,6 +73,7 @@ obj-$(CONFIG_SENSORS_DRIVETEMP)	+= drivetemp.o
>  obj-$(CONFIG_SENSORS_DS620)	+= ds620.o
>  obj-$(CONFIG_SENSORS_DS1621)	+= ds1621.o
>  obj-$(CONFIG_SENSORS_EMC1403)	+= emc1403.o
> +obj-$(CONFIG_SENSORS_EMC2101)	+= emc2101.o
>  obj-$(CONFIG_SENSORS_EMC2103)	+= emc2103.o
>  obj-$(CONFIG_SENSORS_EMC2305)	+= emc2305.o
>  obj-$(CONFIG_SENSORS_EMC6W201)	+= emc6w201.o
> diff --git a/drivers/hwmon/emc2101.c b/drivers/hwmon/emc2101.c
> new file mode 100644
> index 000000000000..65f2eff27aaf
> --- /dev/null
> +++ b/drivers/hwmon/emc2101.c
> @@ -0,0 +1,2176 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Driver for Microchip EMC2101 fan controller.
> + *
> + * Copyright 2025 Álvaro Fernández Rojas <noltari@gmail.com>
> + */
> +
> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/jiffies.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/slab.h>
> +#include <linux/util_macros.h>
> +
> +#define REG_TEMP_INT			0x00
> +#define REG_TEMP_EXT_HI			0x01
> +#define REG_STATUS			0x02
> +#define  ADC_BUSY			BIT(7)
> +#define  TEMP_INT_HIGH			BIT(6)
> +#define  EEPROM_ERROR			BIT(5)
> +#define  TEMP_EXT_HIGH			BIT(4)
> +#define  TEMP_EXT_LOW			BIT(3)
> +#define  TEMP_EXT_FAULT			BIT(2)
> +#define  TEMP_EXT_CRIT			BIT(1)
> +#define  TACH_LOW			BIT(0)
> +#define REG_CONFIG			0x03
> +#define  ALERT_IRQ_ACK			BIT(7)
> +#define  FAN_STANDBY_ENABLE		BIT(6)
> +#define  FAN_STANDBY_MODE		BIT(5)
> +#define  FAN_MODE_DAC			BIT(4)
> +#define  SMBUS_TOUT_DISABLE		BIT(3)
> +#define  PIN_FUNC_TACH			BIT(2)
> +#define  TEMP_EXT_CRIT_UNLOCK		BIT(1)
> +#define  PIN_ASSERT_3_EXC		BIT(0)
> +#define REG_CONV_RATE			0x04
> +#define  CONV_RATE_MASK			0xf
> +#define REG_TEMP_INT_MAX		0x05
> +#define REG_TEMP_EXT_MAX_HI		0x07
> +#define REG_TEMP_EXT_MIN_HI		0x08
> +#define REG_TEMP_EXT_FORCE		0x0c
> +#define REG_ONE_SHOT			0x0f
> +#define REG_TEMP_EXT_LO			0x10
> +#define REG_SCRATCHPAD_1		0x11
> +#define REG_SCRATCHPAD_2		0x12
> +#define REG_TEMP_EXT_MAX_LO		0x13
> +#define REG_TEMP_EXT_MIN_LO		0x14
> +#define REG_ALERT_MASK			0x16
> +#define  IRQ_TEMP_INT_MAX_DISABLE	BIT(6)
> +#define  IRQ_TEMP_EXT_MAX_DISABLE	BIT(4)
> +#define  IRQ_TEMP_EXT_MIN_DISABLE	BIT(3)
> +#define  IRQ_TEMP_EXT_CRIT_DISABLE	BIT(1)
> +#define  IRQ_TACH_MIN_DISABLE		BIT(0)
> +#define REG_EXT_IDEALITY		0x17
> +#define  EXT_IDEALITY_START		9846
> +#define  EXT_IDEALITY_STEP		13
> +#define  EXT_IDEALITY_VAL(x)		(EXT_IDEALITY_START + \
> +					 ((x) * EXT_IDEALITY_STEP))
> +#define  EXT_IDEALITY_MASK		0x3f
> +#define REG_BETA_COMP			0x18
> +#define  BETA_COMP_AUTO			BIT(3)
> +#define  BETA_COMP_DISABLE		7
> +#define  BETA_COMP_2_33			6
> +#define  BETA_COMP_1_00			5
> +#define  BETA_COMP_0_43			4
> +#define  BETA_COMP_0_33			3
> +#define  BETA_COMP_0_25			2
> +#define  BETA_COMP_0_18			1
> +#define  BETA_COMP_0_11			0
> +#define  BETA_COMP_MASK			0x7
> +#define REG_TEMP_EXT_CRIT		0x19
> +#define REG_TEMP_EXT_CRIT_HYST		0x21
> +#define REG_TACH_LO			0x46
> +#define REG_TACH_HI			0x47
> +#define REG_TACH_MIN_LO			0x48
> +#define REG_TACH_MIN_HI			0x49
> +#define REG_FAN_CONFIG			0x4a
> +#define  FAN_EXT_TEMP_FORCE		BIT(6)
> +#define  FAN_LUT_DISABLE		BIT(5)
> +#define  FAN_POL_INV			BIT(4)
> +#define  FAN_CLK_SEL			BIT(3)
> +#define  FAN_CLK_OVR			BIT(2)
> +#define  TACH_FALSE_READ_DISABLE	BIT(0)
> +#define  TACH_FALSE_READ_MASK		0x3
> +#define REG_FAN_SPIN			0x4b
> +#define  FAN_SPIN_UP_ABORT		BIT(5)
> +#define  FAN_SPIN_UP_POWER_SHIFT	3
> +#define  FAN_SPIN_UP_POWER_100		(3 << FAN_SPIN_UP_POWER_SHIFT)
> +#define  FAN_SPIN_UP_POWER_75		(2 << FAN_SPIN_UP_POWER_SHIFT)
> +#define  FAN_SPIN_UP_POWER_50		(1 << FAN_SPIN_UP_POWER_SHIFT)
> +#define  FAN_SPIN_UP_POWER_0		(0 << FAN_SPIN_UP_POWER_SHIFT)
> +#define  FAN_SPIN_UP_POWER_MASK		(0x3 << FAN_SPIN_UP_POWER_SHIFT)
> +#define  FAN_SPIN_UP_TIME_3200		7
> +#define  FAN_SPIN_UP_TIME_1600		6
> +#define  FAN_SPIN_UP_TIME_800		5
> +#define  FAN_SPIN_UP_TIME_400		4
> +#define  FAN_SPIN_UP_TIME_200		3
> +#define  FAN_SPIN_UP_TIME_100		2
> +#define  FAN_SPIN_UP_TIME_50		1
> +#define  FAN_SPIN_UP_TIME_0		0
> +#define  FAN_SPIN_UP_TIME_MASK		0x7
> +#define REG_FAN_SET			0x4c
> +#define  FAN_SET_MASK			0x3f
> +#define REG_PWM_FREQ			0x4d
> +#define  PWM_FREQ_MASK			0x1f
> +#define REG_PWM_FREQ_DIV		0x4e
> +#define REG_FAN_LUT_HYST		0x4f
> +#define  FAN_LUT_HYST_MASK		0x1f
> +#define REG_FAN_LUT_TEMP(x)		(0x50 + (0x2 * (x)))
> +/* Write only with FAN_LUT_DISABLE */
> +#define  FAN_LUT_TEMP_MASK		0x7f
> +#define REG_FAN_LUT_SPEED(x)		(0x51 + (0x2 * (x)))
> +/* Write only with FAN_LUT_DISABLE */
> +#define  FAN_LUT_SPEED_MASK		0x3f
> +#define REG_AVG_FILTER			0xbf
> +#define  FILTER_SHIFT			1
> +#define  FILTER_L2			(3 << FILTER_SHIFT)
> +#define  FILTER_L1			(1 << FILTER_SHIFT)
> +#define  FILTER_NONE			(0 << FILTER_SHIFT)
> +#define  FILTER_MASK			(0x3 << FILTER_SHIFT)
> +#define  ALERT_PIN_TEMP_COMP		BIT(0)
> +#define REG_PRODUCT_ID			0xfd
> +#define REG_MANUFACTURER_ID		0xfe
> +#define REG_REVISION			0xff
> +
> +#define CLK_FREQ_ALT			1400
> +#define CLK_FREQ_BASE			360000
> +
> +#define FAN_LUT_COUNT			8
> +#define FAN_LUT_HYST_DEF		4
> +#define FAN_LUT_HYST_MIN		0
> +#define FAN_LUT_HYST_MAX		31
> +#define FAN_MIN_READ			0xffff
> +#define FAN_RPM_FACTOR			5400000
> +
> +#define MANUFACTURER_ID			0x5d
> +
> +#define TEMP_EXT_HI_FAULT		0x7f
> +#define TEMP_EXT_LO_FAULT_OPEN		0x00
> +#define TEMP_EXT_LO_FAULT_SHORT		0xe0
> +
> +#define TEMP_LO_FRAC			125
> +#define TEMP_LO_SHIFT			5
> +#define TEMP_LO_MASK			(0x3 << TEMP_LO_SHIFT)
> +
> +#define TEMP_MIN			-64
> +#define TEMP_MAX			127
> +#define TEMP_MAX_FRAC			750
> +
> +enum emc2101_fan_spin_up_abort {
> +	EMC2101_FAN_SPIN_ABORT_DISABLE = 0,
> +	EMC2101_FAN_SPIN_ABORT_ENABLE
> +};
> +
> +enum emc2101_fan_standby {
> +	EMC2101_FAN_STBY_DISABLE = 0,
> +	EMC2101_FAN_STBY_ENABLE
> +};
> +
> +enum emc2101_mode {
> +	EMC2101_MODE_PWM = 0,
> +	EMC2101_MODE_DAC
> +};
> +
> +enum ecm2101_product_id {
> +	EMC2101 = 0x16,
> +	EMC2101_R = 0x28
> +};
> +
> +enum emc2101_pwm_enable {
> +	EMC2101_PWM_MANUAL = 1,
> +	EMC2101_PWM_LUT = 2
> +};
> +
> +enum emc2101_pwm_polarity {
> +	EMC2101_POL_NORMAL = 0,
> +	EMC2101_POL_INVERTED
> +};
> +
> +enum emc2101_temp_channels {
> +	EMC2101_TC_INT = 0,
> +	EMC2101_TC_EXT,
> +	EMC2101_TC_FORCE,
> +	EMC2101_TC_NUM
> +};
> +
> +enum emc2101_temp_diode {
> +	EMC2101_TD_CPU = 1,
> +	EMC2101_TD_2N3904 = 2
> +};
> +
> +struct emc2101_data {
> +	struct i2c_client *client;
> +	struct device *dev;
> +	struct mutex mutex;

Add a comment describing what you are protecting here. It looks so far
like you could just use regmap and drop the mutex, but I didn't check
thoroughly.

> +};



...

> +
> +static int emc2101_probe(struct i2c_client *client)
> +{
> +	struct i2c_adapter *adapter = client->adapter;
> +	struct device *dev = &client->dev;
> +	struct emc2101_data *data;
> +	struct device *hwmon_dev;
> +
> +	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
> +		return -EIO;
> +
> +	data = devm_kzalloc(dev, sizeof(struct emc2101_data), GFP_KERNEL);

sizeof(*)

> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->client = client;
> +	data->dev = dev;
> +	mutex_init(&data->mutex);
> +
> +	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
> +							 &emc2101_chip_info,
> +							 emc2101_hwmon_groups);
> +	if (IS_ERR(hwmon_dev))
> +		return PTR_ERR(hwmon_dev);
> +
> +	dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);

Drivers should be silent oon success. We already know that this probed
based on sysfs.

> +
> +	return emc2101_init(data);
> +}
> +
> +static int emc2101_detect(struct i2c_client *client, struct i2c_board_info *info)
> +{
> +	struct i2c_adapter *adapter = client->adapter;
> +	s32 manufacturer, product, revision;
> +	struct device *dev = &adapter->dev;
> +
> +	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
> +		return -ENODEV;
> +
> +	manufacturer = i2c_smbus_read_byte_data(client, REG_MANUFACTURER_ID);
> +	if (manufacturer != MANUFACTURER_ID)
> +		return -ENODEV;
> +
> +	product = i2c_smbus_read_byte_data(client, REG_PRODUCT_ID);
> +	switch (product) {
> +	case EMC2101:
> +		strscpy(info->type, "emc2101", I2C_NAME_SIZE);
> +		break;
> +	case EMC2101_R:
> +		strscpy(info->type, "emc2101-r", I2C_NAME_SIZE);
> +		break;
> +	default:
> +		return -ENODEV;
> +	}
> +
> +	revision = i2c_smbus_read_byte_data(client, REG_REVISION);
> +
> +	dev_info(dev, "Found %s at 0x%02x (rev 0x%02x).\n",
> +		 info->type, client->addr, revision);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id emc2101_ids[] = {
> +	{ "emc2101" },
> +	{ "emc2101-r" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, emc2101_ids);
> +
> +static const struct of_device_id emc2101_of_match_table[] = {
> +	{ .compatible = "microchip,emc2101", },
> +	{ .compatible = "microchip,emc2101-r", },

Devices are compatible then? Express it in the bindings and drop this entry.

> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, emc2101_of_match_table);
> +
> +static const unsigned short emc2101_address_list[] = {
> +	0x4c, I2C_CLIENT_END
> +};
> +
Best regards,
Krzysztof

Re: [PATCH] drivers: hwmon: add EMC2101 driver

[Álvaro Fernández Rojas]

Hi Krzysztof,

El mié, 2 jul 2025 a las 10:35, Krzysztof Kozlowski
(<krzk@kernel.org>) escribió:
>
> On 01/07/2025 20:12, Álvaro Fernández Rojas wrote:
> > The Microchip EMC2101 is a SMBus 2.0 fan controller with temperature
> > monitoring.
> > It supports up to 1 fan, 1 internal temperature sensor, 1 external
> > temperature sensor and an 8 entry look up table to create a
> > programmable temperature response.
> >
> > Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> > ---
> >  drivers/hwmon/Kconfig   |   10 +
> >  drivers/hwmon/Makefile  |    1 +
> >  drivers/hwmon/emc2101.c | 2175 +++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 2186 insertions(+)
> >  create mode 100644 drivers/hwmon/emc2101.c
> >
> >  v2: multiple improvements:
> >   - Remove FAN_RPM_MIN definition.
> >   - Rename FAN_FALSE_READ to FAN_MIN_READ.
> >   - pwm_auto_point_temp_hyst_store(): simplify function.
> >   - emc2101_fan_min_read(): add missing FAN_MIN_READ condition.
> >   - emc2101_fan_min_write(): fix tach_count calculation.
> >   - emc2101_init(): fix REG_TACH_MIN value.
> >
> > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> > index 079620dd4286..360b9f66275c 100644
> > --- a/drivers/hwmon/Kconfig
> > +++ b/drivers/hwmon/Kconfig
> > @@ -2002,6 +2002,16 @@ config SENSORS_EMC1403
> >         Threshold values can be configured using sysfs.
> >         Data from the different diodes are accessible via sysfs.
> >
> > +config SENSORS_EMC2101
> > +     tristate "SMSC EMC2101"
> > +     depends on I2C
> > +     help
> > +       If you say yes here you get support for the SMSC EMC2101
> > +       fan controller chips.
> > +
> > +       This driver can also be built as a module. If so, the module
> > +       will be called emc2101.
> > +
> >  config SENSORS_EMC2103
> >       tristate "SMSC EMC2103"
> >       depends on I2C
> > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> > index 48e5866c0c9a..70e95096c6f2 100644
> > --- a/drivers/hwmon/Makefile
> > +++ b/drivers/hwmon/Makefile
> > @@ -73,6 +73,7 @@ obj-$(CONFIG_SENSORS_DRIVETEMP)     += drivetemp.o
> >  obj-$(CONFIG_SENSORS_DS620)  += ds620.o
> >  obj-$(CONFIG_SENSORS_DS1621) += ds1621.o
> >  obj-$(CONFIG_SENSORS_EMC1403)        += emc1403.o
> > +obj-$(CONFIG_SENSORS_EMC2101)        += emc2101.o
> >  obj-$(CONFIG_SENSORS_EMC2103)        += emc2103.o
> >  obj-$(CONFIG_SENSORS_EMC2305)        += emc2305.o
> >  obj-$(CONFIG_SENSORS_EMC6W201)       += emc6w201.o
> > diff --git a/drivers/hwmon/emc2101.c b/drivers/hwmon/emc2101.c
> > new file mode 100644
> > index 000000000000..65f2eff27aaf
> > --- /dev/null
> > +++ b/drivers/hwmon/emc2101.c
> > @@ -0,0 +1,2176 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * Driver for Microchip EMC2101 fan controller.
> > + *
> > + * Copyright 2025 Álvaro Fernández Rojas <noltari@gmail.com>
> > + */
> > +
> > +#include <linux/err.h>
> > +#include <linux/hwmon.h>
> > +#include <linux/hwmon-sysfs.h>
> > +#include <linux/i2c.h>
> > +#include <linux/init.h>
> > +#include <linux/jiffies.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/slab.h>
> > +#include <linux/util_macros.h>
> > +
> > +#define REG_TEMP_INT                 0x00
> > +#define REG_TEMP_EXT_HI                      0x01
> > +#define REG_STATUS                   0x02
> > +#define  ADC_BUSY                    BIT(7)
> > +#define  TEMP_INT_HIGH                       BIT(6)
> > +#define  EEPROM_ERROR                        BIT(5)
> > +#define  TEMP_EXT_HIGH                       BIT(4)
> > +#define  TEMP_EXT_LOW                        BIT(3)
> > +#define  TEMP_EXT_FAULT                      BIT(2)
> > +#define  TEMP_EXT_CRIT                       BIT(1)
> > +#define  TACH_LOW                    BIT(0)
> > +#define REG_CONFIG                   0x03
> > +#define  ALERT_IRQ_ACK                       BIT(7)
> > +#define  FAN_STANDBY_ENABLE          BIT(6)
> > +#define  FAN_STANDBY_MODE            BIT(5)
> > +#define  FAN_MODE_DAC                        BIT(4)
> > +#define  SMBUS_TOUT_DISABLE          BIT(3)
> > +#define  PIN_FUNC_TACH                       BIT(2)
> > +#define  TEMP_EXT_CRIT_UNLOCK                BIT(1)
> > +#define  PIN_ASSERT_3_EXC            BIT(0)
> > +#define REG_CONV_RATE                        0x04
> > +#define  CONV_RATE_MASK                      0xf
> > +#define REG_TEMP_INT_MAX             0x05
> > +#define REG_TEMP_EXT_MAX_HI          0x07
> > +#define REG_TEMP_EXT_MIN_HI          0x08
> > +#define REG_TEMP_EXT_FORCE           0x0c
> > +#define REG_ONE_SHOT                 0x0f
> > +#define REG_TEMP_EXT_LO                      0x10
> > +#define REG_SCRATCHPAD_1             0x11
> > +#define REG_SCRATCHPAD_2             0x12
> > +#define REG_TEMP_EXT_MAX_LO          0x13
> > +#define REG_TEMP_EXT_MIN_LO          0x14
> > +#define REG_ALERT_MASK                       0x16
> > +#define  IRQ_TEMP_INT_MAX_DISABLE    BIT(6)
> > +#define  IRQ_TEMP_EXT_MAX_DISABLE    BIT(4)
> > +#define  IRQ_TEMP_EXT_MIN_DISABLE    BIT(3)
> > +#define  IRQ_TEMP_EXT_CRIT_DISABLE   BIT(1)
> > +#define  IRQ_TACH_MIN_DISABLE                BIT(0)
> > +#define REG_EXT_IDEALITY             0x17
> > +#define  EXT_IDEALITY_START          9846
> > +#define  EXT_IDEALITY_STEP           13
> > +#define  EXT_IDEALITY_VAL(x)         (EXT_IDEALITY_START + \
> > +                                      ((x) * EXT_IDEALITY_STEP))
> > +#define  EXT_IDEALITY_MASK           0x3f
> > +#define REG_BETA_COMP                        0x18
> > +#define  BETA_COMP_AUTO                      BIT(3)
> > +#define  BETA_COMP_DISABLE           7
> > +#define  BETA_COMP_2_33                      6
> > +#define  BETA_COMP_1_00                      5
> > +#define  BETA_COMP_0_43                      4
> > +#define  BETA_COMP_0_33                      3
> > +#define  BETA_COMP_0_25                      2
> > +#define  BETA_COMP_0_18                      1
> > +#define  BETA_COMP_0_11                      0
> > +#define  BETA_COMP_MASK                      0x7
> > +#define REG_TEMP_EXT_CRIT            0x19
> > +#define REG_TEMP_EXT_CRIT_HYST               0x21
> > +#define REG_TACH_LO                  0x46
> > +#define REG_TACH_HI                  0x47
> > +#define REG_TACH_MIN_LO                      0x48
> > +#define REG_TACH_MIN_HI                      0x49
> > +#define REG_FAN_CONFIG                       0x4a
> > +#define  FAN_EXT_TEMP_FORCE          BIT(6)
> > +#define  FAN_LUT_DISABLE             BIT(5)
> > +#define  FAN_POL_INV                 BIT(4)
> > +#define  FAN_CLK_SEL                 BIT(3)
> > +#define  FAN_CLK_OVR                 BIT(2)
> > +#define  TACH_FALSE_READ_DISABLE     BIT(0)
> > +#define  TACH_FALSE_READ_MASK                0x3
> > +#define REG_FAN_SPIN                 0x4b
> > +#define  FAN_SPIN_UP_ABORT           BIT(5)
> > +#define  FAN_SPIN_UP_POWER_SHIFT     3
> > +#define  FAN_SPIN_UP_POWER_100               (3 << FAN_SPIN_UP_POWER_SHIFT)
> > +#define  FAN_SPIN_UP_POWER_75                (2 << FAN_SPIN_UP_POWER_SHIFT)
> > +#define  FAN_SPIN_UP_POWER_50                (1 << FAN_SPIN_UP_POWER_SHIFT)
> > +#define  FAN_SPIN_UP_POWER_0         (0 << FAN_SPIN_UP_POWER_SHIFT)
> > +#define  FAN_SPIN_UP_POWER_MASK              (0x3 << FAN_SPIN_UP_POWER_SHIFT)
> > +#define  FAN_SPIN_UP_TIME_3200               7
> > +#define  FAN_SPIN_UP_TIME_1600               6
> > +#define  FAN_SPIN_UP_TIME_800                5
> > +#define  FAN_SPIN_UP_TIME_400                4
> > +#define  FAN_SPIN_UP_TIME_200                3
> > +#define  FAN_SPIN_UP_TIME_100                2
> > +#define  FAN_SPIN_UP_TIME_50         1
> > +#define  FAN_SPIN_UP_TIME_0          0
> > +#define  FAN_SPIN_UP_TIME_MASK               0x7
> > +#define REG_FAN_SET                  0x4c
> > +#define  FAN_SET_MASK                        0x3f
> > +#define REG_PWM_FREQ                 0x4d
> > +#define  PWM_FREQ_MASK                       0x1f
> > +#define REG_PWM_FREQ_DIV             0x4e
> > +#define REG_FAN_LUT_HYST             0x4f
> > +#define  FAN_LUT_HYST_MASK           0x1f
> > +#define REG_FAN_LUT_TEMP(x)          (0x50 + (0x2 * (x)))
> > +/* Write only with FAN_LUT_DISABLE */
> > +#define  FAN_LUT_TEMP_MASK           0x7f
> > +#define REG_FAN_LUT_SPEED(x)         (0x51 + (0x2 * (x)))
> > +/* Write only with FAN_LUT_DISABLE */
> > +#define  FAN_LUT_SPEED_MASK          0x3f
> > +#define REG_AVG_FILTER                       0xbf
> > +#define  FILTER_SHIFT                        1
> > +#define  FILTER_L2                   (3 << FILTER_SHIFT)
> > +#define  FILTER_L1                   (1 << FILTER_SHIFT)
> > +#define  FILTER_NONE                 (0 << FILTER_SHIFT)
> > +#define  FILTER_MASK                 (0x3 << FILTER_SHIFT)
> > +#define  ALERT_PIN_TEMP_COMP         BIT(0)
> > +#define REG_PRODUCT_ID                       0xfd
> > +#define REG_MANUFACTURER_ID          0xfe
> > +#define REG_REVISION                 0xff
> > +
> > +#define CLK_FREQ_ALT                 1400
> > +#define CLK_FREQ_BASE                        360000
> > +
> > +#define FAN_LUT_COUNT                        8
> > +#define FAN_LUT_HYST_DEF             4
> > +#define FAN_LUT_HYST_MIN             0
> > +#define FAN_LUT_HYST_MAX             31
> > +#define FAN_MIN_READ                 0xffff
> > +#define FAN_RPM_FACTOR                       5400000
> > +
> > +#define MANUFACTURER_ID                      0x5d
> > +
> > +#define TEMP_EXT_HI_FAULT            0x7f
> > +#define TEMP_EXT_LO_FAULT_OPEN               0x00
> > +#define TEMP_EXT_LO_FAULT_SHORT              0xe0
> > +
> > +#define TEMP_LO_FRAC                 125
> > +#define TEMP_LO_SHIFT                        5
> > +#define TEMP_LO_MASK                 (0x3 << TEMP_LO_SHIFT)
> > +
> > +#define TEMP_MIN                     -64
> > +#define TEMP_MAX                     127
> > +#define TEMP_MAX_FRAC                        750
> > +
> > +enum emc2101_fan_spin_up_abort {
> > +     EMC2101_FAN_SPIN_ABORT_DISABLE = 0,
> > +     EMC2101_FAN_SPIN_ABORT_ENABLE
> > +};
> > +
> > +enum emc2101_fan_standby {
> > +     EMC2101_FAN_STBY_DISABLE = 0,
> > +     EMC2101_FAN_STBY_ENABLE
> > +};
> > +
> > +enum emc2101_mode {
> > +     EMC2101_MODE_PWM = 0,
> > +     EMC2101_MODE_DAC
> > +};
> > +
> > +enum ecm2101_product_id {
> > +     EMC2101 = 0x16,
> > +     EMC2101_R = 0x28
> > +};
> > +
> > +enum emc2101_pwm_enable {
> > +     EMC2101_PWM_MANUAL = 1,
> > +     EMC2101_PWM_LUT = 2
> > +};
> > +
> > +enum emc2101_pwm_polarity {
> > +     EMC2101_POL_NORMAL = 0,
> > +     EMC2101_POL_INVERTED
> > +};
> > +
> > +enum emc2101_temp_channels {
> > +     EMC2101_TC_INT = 0,
> > +     EMC2101_TC_EXT,
> > +     EMC2101_TC_FORCE,
> > +     EMC2101_TC_NUM
> > +};
> > +
> > +enum emc2101_temp_diode {
> > +     EMC2101_TD_CPU = 1,
> > +     EMC2101_TD_2N3904 = 2
> > +};
> > +
> > +struct emc2101_data {
> > +     struct i2c_client *client;
> > +     struct device *dev;
> > +     struct mutex mutex;
>
> Add a comment describing what you are protecting here. It looks so far
> like you could just use regmap and drop the mutex, but I didn't check
> thoroughly.

The EMC2101 datasheet is explicit about the Look Up Table registers
(REG_FAN_LUT_TEMP and REG_FAN_LUT_SPEED) being RO if FAN_LUT_DISABLE
isn't set, so I believe that we need the mutex even if we switch to
regmap.
I will add an explanation with that in the next version.
Should I still switch the implementation to regmap considering that we
need a mutex?

>
> > +};
>
>
>
> ...
>
> > +
> > +static int emc2101_probe(struct i2c_client *client)
> > +{
> > +     struct i2c_adapter *adapter = client->adapter;
> > +     struct device *dev = &client->dev;
> > +     struct emc2101_data *data;
> > +     struct device *hwmon_dev;
> > +
> > +     if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
> > +             return -EIO;
> > +
> > +     data = devm_kzalloc(dev, sizeof(struct emc2101_data), GFP_KERNEL);
>
> sizeof(*)
>
> > +     if (!data)
> > +             return -ENOMEM;
> > +
> > +     data->client = client;
> > +     data->dev = dev;
> > +     mutex_init(&data->mutex);
> > +
> > +     hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
> > +                                                      &emc2101_chip_info,
> > +                                                      emc2101_hwmon_groups);
> > +     if (IS_ERR(hwmon_dev))
> > +             return PTR_ERR(hwmon_dev);
> > +
> > +     dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
>
> Drivers should be silent oon success. We already know that this probed
> based on sysfs.
>
> > +
> > +     return emc2101_init(data);
> > +}
> > +
> > +static int emc2101_detect(struct i2c_client *client, struct i2c_board_info *info)
> > +{
> > +     struct i2c_adapter *adapter = client->adapter;
> > +     s32 manufacturer, product, revision;
> > +     struct device *dev = &adapter->dev;
> > +
> > +     if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
> > +             return -ENODEV;
> > +
> > +     manufacturer = i2c_smbus_read_byte_data(client, REG_MANUFACTURER_ID);
> > +     if (manufacturer != MANUFACTURER_ID)
> > +             return -ENODEV;
> > +
> > +     product = i2c_smbus_read_byte_data(client, REG_PRODUCT_ID);
> > +     switch (product) {
> > +     case EMC2101:
> > +             strscpy(info->type, "emc2101", I2C_NAME_SIZE);
> > +             break;
> > +     case EMC2101_R:
> > +             strscpy(info->type, "emc2101-r", I2C_NAME_SIZE);
> > +             break;
> > +     default:
> > +             return -ENODEV;
> > +     }
> > +
> > +     revision = i2c_smbus_read_byte_data(client, REG_REVISION);
> > +
> > +     dev_info(dev, "Found %s at 0x%02x (rev 0x%02x).\n",
> > +              info->type, client->addr, revision);
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct i2c_device_id emc2101_ids[] = {
> > +     { "emc2101" },
> > +     { "emc2101-r" },
> > +     { }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, emc2101_ids);
> > +
> > +static const struct of_device_id emc2101_of_match_table[] = {
> > +     { .compatible = "microchip,emc2101", },
> > +     { .compatible = "microchip,emc2101-r", },
>
> Devices are compatible then? Express it in the bindings and drop this entry.
>
> > +     { },
> > +};
> > +MODULE_DEVICE_TABLE(of, emc2101_of_match_table);
> > +
> > +static const unsigned short emc2101_address_list[] = {
> > +     0x4c, I2C_CLIENT_END
> > +};
> > +
> Best regards,
> Krzysztof

Re: [PATCH] drivers: hwmon: add EMC2101 driver

[Guenter Roeck]

On Thu, Jul 03, 2025 at 09:23:41AM +0200, Álvaro Fernández Rojas wrote:
> >
> > Add a comment describing what you are protecting here. It looks so far
> > like you could just use regmap and drop the mutex, but I didn't check
> > thoroughly.
> 
> The EMC2101 datasheet is explicit about the Look Up Table registers
> (REG_FAN_LUT_TEMP and REG_FAN_LUT_SPEED) being RO if FAN_LUT_DISABLE
> isn't set, so I believe that we need the mutex even if we switch to
> regmap.
> I will add an explanation with that in the next version.
> Should I still switch the implementation to regmap considering that we
> need a mutex?
> 
What does r/w vs. r/o register access have to do with locking ?

Guenter

Re: [PATCH] drivers: hwmon: add EMC2101 driver

[Álvaro Fernández Rojas]

Hi Guenter,

El vie, 4 jul 2025 a las 2:25, Guenter Roeck (<linux@roeck-us.net>) escribió:
>
> On Thu, Jul 03, 2025 at 09:23:41AM +0200, Álvaro Fernández Rojas wrote:
> > >
> > > Add a comment describing what you are protecting here. It looks so far
> > > like you could just use regmap and drop the mutex, but I didn't check
> > > thoroughly.
> >
> > The EMC2101 datasheet is explicit about the Look Up Table registers
> > (REG_FAN_LUT_TEMP and REG_FAN_LUT_SPEED) being RO if FAN_LUT_DISABLE
> > isn't set, so I believe that we need the mutex even if we switch to
> > regmap.
> > I will add an explanation with that in the next version.
> > Should I still switch the implementation to regmap considering that we
> > need a mutex?
> >
> What does r/w vs. r/o register access have to do with locking ?

FAN_LUT_DISABLE bit can be set or cleared when pwm_enable is modified,
but we need it to be set in order to be able to modify
REG_FAN_LUT_TEMP and REG_FAN_LUT_SPEED registers.
If FAN_LUT_DISABLE bit isn't set, any attempt to modify
REG_FAN_LUT_TEMP and REG_FAN_LUT_SPEED registers won't work because
they would be RO.
Therefore, we need a lock to ensure that FAN_LUT_DISABLE is kept while
modifying those registers.
Please, take a look at emc2101_pwm_enable_write() and
__pwm_auto_point_temp_store().

>
> Guenter

Best regards,
Álvaro.

Re: [PATCH] drivers: hwmon: add EMC2101 driver

[Guenter Roeck]

On Fri, Jul 04, 2025 at 09:26:16AM +0200, Álvaro Fernández Rojas wrote:
> Hi Guenter,
> 
> El vie, 4 jul 2025 a las 2:25, Guenter Roeck (<linux@roeck-us.net>) escribió:
> >
> > On Thu, Jul 03, 2025 at 09:23:41AM +0200, Álvaro Fernández Rojas wrote:
> > > >
> > > > Add a comment describing what you are protecting here. It looks so far
> > > > like you could just use regmap and drop the mutex, but I didn't check
> > > > thoroughly.
> > >
> > > The EMC2101 datasheet is explicit about the Look Up Table registers
> > > (REG_FAN_LUT_TEMP and REG_FAN_LUT_SPEED) being RO if FAN_LUT_DISABLE
> > > isn't set, so I believe that we need the mutex even if we switch to
> > > regmap.
> > > I will add an explanation with that in the next version.
> > > Should I still switch the implementation to regmap considering that we
> > > need a mutex?
> > >
> > What does r/w vs. r/o register access have to do with locking ?
> 
> FAN_LUT_DISABLE bit can be set or cleared when pwm_enable is modified,
> but we need it to be set in order to be able to modify
> REG_FAN_LUT_TEMP and REG_FAN_LUT_SPEED registers.
> If FAN_LUT_DISABLE bit isn't set, any attempt to modify
> REG_FAN_LUT_TEMP and REG_FAN_LUT_SPEED registers won't work because
> they would be RO.
> Therefore, we need a lock to ensure that FAN_LUT_DISABLE is kept while
> modifying those registers.
> Please, take a look at emc2101_pwm_enable_write() and
> __pwm_auto_point_temp_store().
> 
Thanks for the clarification. Please add that as comment into the code.

Regmap is still valuable even if local locking is needed. It provides
caching for non-volatile registers, and it provides various useful API
functions (for example for bit value changes) which you otherwise have
to implement by hand.

Guenter