[PATCH v3] hwmon: (lm75) Add support for Nuvoton NCT7715

[hsyemail2]

From: Sheng-Yuan Huang <syhuang3@xxxxxxxxxxx>

The Nuvoton NCT7715 is compatible with the LM75 temperature and
limit register layout. Its 16-bit configuration register shares the
TMP112 configuration layout.

Signed-off-by: Sheng-Yuan Huang <syhuang3@xxxxxxxxxxx>
---
v3:
- Reuse the existing TMP112 handling for NCT7715 configuration,
  update intervals, and alarms.

v2:
- Use the standard SMBus word representation for the NCT7715
  configuration register, removing the NCT7715-specific byte swapping
  and updating its configuration masks accordingly.
  
 .../devicetree/bindings/hwmon/lm75.yaml       |  2 ++
 Documentation/hwmon/lm75.rst                  |  6 ++++++
 drivers/hwmon/lm75.c                          | 21 ++++++++++++++++++-
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/hwmon/lm75.yaml b/Documentation/devicetree/bindings/hwmon/lm75.yaml
index b48bf3fd721f..d55b8b7e49c5 100644
--- a/Documentation/devicetree/bindings/hwmon/lm75.yaml
+++ b/Documentation/devicetree/bindings/hwmon/lm75.yaml
@@ -31,6 +31,7 @@ properties:
       - nxp,p3t1750
       - nxp,p3t1755
       - nxp,pct2075
+      - nuvoton,nct7715
       - st,stds75
       - st,stlm75
       - microchip,tcn75
@@ -78,6 +79,7 @@ allOf:
                 - ti,tmp101
                 - ti,tmp112
                 - ti,tmp75
+                - nuvoton,nct7715
     then:
       properties:
         interrupts: false
diff --git a/Documentation/hwmon/lm75.rst b/Documentation/hwmon/lm75.rst
index ca46754e028b..fac0b8f29ddc 100644
--- a/Documentation/hwmon/lm75.rst
+++ b/Documentation/hwmon/lm75.rst
@@ -150,6 +150,12 @@ Supported chips:
 
                https://ams.com/documents/20143/36005/AS6200_DS000449_4-00.pdf
 
+  * Nuvoton NCT7715
+
+    Prefix: 'nct7715'
+
+    Addresses scanned: none
+
 Author: Frodo Looijaard <frodol@xxxxxx>
 
 Description
diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index 2d2d752aeac9..1a98ecb142c9 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -39,6 +39,7 @@ enum lm75_type {		/* keep sorted in alphabetical order */
 	max6626,
 	max31725,
 	mcp980x,
+	nct7715,
 	p3t1750,
 	p3t1755,
 	pct2075,
@@ -259,6 +260,16 @@ static const struct lm75_params device_params[] = {
 		.sample_times = (unsigned int []){ 30, 60, 120, 240 },
 		.resolutions = (u8 []) {9, 10, 11, 12 },
 	},
+	[nct7715] = {
+		.config_reg_16bits = true,
+		.set_mask = 0x8060,	/* 12-bit mode, 4 samples / second */
+		.clr_mask = 1 << 7,	/* no one-shot mode */
+		.default_resolution = 12,
+		.default_sample_time = 250,
+		.num_sample_times = 4,
+		.sample_times = (unsigned int []){ 125, 250, 1000, 4000 },
+		.alarm = true,
+	},
 	[tmp100] = {
 		.set_mask = 3 << 5,	/* 12-bit mode */
 		.clr_mask = 1 << 7,	/* not one-shot mode */
@@ -417,6 +428,7 @@ static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
 		if (attr == hwmon_temp_alarm) {
 			switch (data->kind) {
 			case as6200:
+			case nct7715:
 			case tmp112:
 				*val = !!(regval & BIT(13)) == !!(regval & BIT(2));
 				break;
@@ -486,6 +498,7 @@ static int lm75_update_interval(struct device *dev, long val)
 		if (data->params->resolutions)
 			data->resolution = data->params->resolutions[index];
 		break;
+	case nct7715:
 	case tmp112:
 	case as6200:
 		err = regmap_update_bits(data->regmap, LM75_REG_CONF,
@@ -848,6 +861,7 @@ static const struct i2c_device_id lm75_i2c_ids[] = {
 	{ .name = "max31725", .driver_data = max31725 },
 	{ .name = "max31726", .driver_data = max31725 },
 	{ .name = "mcp980x", .driver_data = mcp980x },
+	{ .name = "nct7715", .driver_data = nct7715 },
 	{ .name = "p3t1750", .driver_data = p3t1750 },
 	{ .name = "p3t1755", .driver_data = p3t1755 },
 	{ .name = "pct2075", .driver_data = pct2075 },
@@ -972,6 +986,10 @@ static const struct of_device_id lm75_of_match[] = {
 		.compatible = "nxp,pct2075",
 		.data = (void *)pct2075
 	},
+	{
+		.compatible = "nuvoton,nct7715",
+		.data = (void *)nct7715
+	},
 	{
 		.compatible = "st,stds75",
 		.data = (void *)stds75
@@ -1129,7 +1147,8 @@ static int lm75_suspend(struct device *dev)
 {
 	struct lm75_data *data = dev_get_drvdata(dev);
 
-	return regmap_update_bits(data->regmap, LM75_REG_CONF, LM75_SHUTDOWN, LM75_SHUTDOWN);
+	return regmap_update_bits(data->regmap, LM75_REG_CONF,
+				  LM75_SHUTDOWN, LM75_SHUTDOWN);
 }
 
 static int lm75_resume(struct device *dev)
-- 
2.43.0