[PATCH v1] hwmon: (lm75) Add support for Nuvoton NCT7715
From: <hidden>
Date: 2026-09-07 08:09:02
Also in:
linux-devicetree, linux-hwmon, lkml
Subsystem:
documentation, hardware monitoring, open firmware and flattened device tree bindings, the rest · Maintainers:
Jonathan Corbet, Guenter Roeck, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
From: Sheng-Yuan Huang <redacted> The Nuvoton NCT7715 is compatible with the LM75 temperature and limit register layout, but its 16-bit configuration register is transmitted most-significant byte first. Add support for the NCT7715, including byte-swapped SMBus accesses for its configuration register. Handle its conversion-rate field and shutdown bit separately, since their bit positions differ from the standard LM75 layout. Signed-off-by: Sheng-Yuan Huang <redacted> --- .../devicetree/bindings/hwmon/lm75.yaml | 1 + Documentation/hwmon/lm75.rst | 6 ++ drivers/hwmon/lm75.c | 57 ++++++++++++++++++- 3 files changed, 62 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/hwmon/lm75.yaml b/Documentation/devicetree/bindings/hwmon/lm75.yaml
index b48bf3fd721f..832a8c5d83e9 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
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@dds.nl> Description
diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index 2d2d752aeac9..0b55f6b7c68d 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,
@@ -107,6 +108,15 @@ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, #define LM75_REG_MAX 0x03 #define PCT2075_REG_IDLE 0x04 +#define NCT7715_CONFIG_RESOLUTION_12_BIT GENMASK(14, 13) +#define NCT7715_CONFIG_SHUTDOWN BIT(8) +#define NCT7715_CONFIG_CONVERSION_RATE_MASK GENMASK(7, 6) +#define NCT7715_CONFIG_EXTENDED_MODE BIT(4) +#define NCT7715_CONFIG_RATE_0_25HZ 0 +#define NCT7715_CONFIG_RATE_1HZ BIT(6) +#define NCT7715_CONFIG_RATE_4HZ BIT(7) +#define NCT7715_CONFIG_RATE_8HZ GENMASK(7, 6) + struct lm75_data { const char *label; struct regmap *regmap;
@@ -122,6 +132,10 @@ struct lm75_data { /*-----------------------------------------------------------------------*/ static const u8 lm75_sample_set_masks[] = { 0 << 5, 1 << 5, 2 << 5, 3 << 5 }; +static const u16 nct7715_sample_set_masks[] = { + NCT7715_CONFIG_RATE_8HZ, NCT7715_CONFIG_RATE_4HZ, + NCT7715_CONFIG_RATE_1HZ, NCT7715_CONFIG_RATE_0_25HZ +}; #define LM75_ALERT_POLARITY_HIGH_8_BIT (BIT(2)) #define LM75_ALERT_POLARITY_HIGH_16_BIT (BIT(2) << 8)
@@ -259,6 +273,15 @@ 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 = NCT7715_CONFIG_RESOLUTION_12_BIT, + .clr_mask = NCT7715_CONFIG_EXTENDED_MODE, + .default_resolution = 12, + .default_sample_time = 250, + .num_sample_times = 4, + .sample_times = (unsigned int []){ 125, 250, 1000, 4000 }, + }, [tmp100] = { .set_mask = 3 << 5, /* 12-bit mode */ .clr_mask = 1 << 7, /* not one-shot mode */
@@ -354,6 +377,11 @@ static inline long lm75_reg_to_mc(s16 temp, u8 resolution) static inline int lm75_write_config(struct lm75_data *data, u16 set_mask, u16 clr_mask) { + if (data->kind == nct7715) + return regmap_update_bits(data->regmap, LM75_REG_CONF, + clr_mask | set_mask | NCT7715_CONFIG_SHUTDOWN, + set_mask); + return regmap_update_bits(data->regmap, LM75_REG_CONF, clr_mask | set_mask | LM75_SHUTDOWN, set_mask); }
@@ -486,6 +514,13 @@ static int lm75_update_interval(struct device *dev, long val) if (data->params->resolutions) data->resolution = data->params->resolutions[index]; break; + case nct7715: + err = lm75_write_config(data, nct7715_sample_set_masks[index], + NCT7715_CONFIG_CONVERSION_RATE_MASK); + if (err) + return err; + data->sample_time = data->params->sample_times[index]; + break; case tmp112: case as6200: err = regmap_update_bits(data->regmap, LM75_REG_CONF,
@@ -609,6 +644,8 @@ static int lm75_i2c_reg_read(void *context, unsigned int reg, unsigned int *val) if (reg == LM75_REG_CONF) { if (!data->params->config_reg_16bits) ret = i2c_smbus_read_byte_data(client, LM75_REG_CONF); + else if (data->kind == nct7715) + ret = i2c_smbus_read_word_swapped(client, LM75_REG_CONF); else ret = i2c_smbus_read_word_data(client, LM75_REG_CONF); } else {
@@ -628,8 +665,11 @@ static int lm75_i2c_reg_write(void *context, unsigned int reg, unsigned int val) if (reg == PCT2075_REG_IDLE || (reg == LM75_REG_CONF && !data->params->config_reg_16bits)) return i2c_smbus_write_byte_data(client, reg, val); - else if (reg == LM75_REG_CONF) + else if (reg == LM75_REG_CONF) { + if (data->kind == nct7715) + return i2c_smbus_write_word_swapped(client, reg, val); return i2c_smbus_write_word_data(client, reg, val); + } return i2c_smbus_write_word_swapped(client, reg, val); }
@@ -848,6 +888,7 @@ 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 +1013,10 @@ 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
@@ -1129,13 +1174,21 @@ 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); + if (data->kind == nct7715) + return regmap_update_bits(data->regmap, LM75_REG_CONF, + NCT7715_CONFIG_SHUTDOWN, + NCT7715_CONFIG_SHUTDOWN); + return regmap_update_bits(data->regmap, LM75_REG_CONF, + LM75_SHUTDOWN, LM75_SHUTDOWN); } static int lm75_resume(struct device *dev) { struct lm75_data *data = dev_get_drvdata(dev); + if (data->kind == nct7715) + return regmap_update_bits(data->regmap, LM75_REG_CONF, + NCT7715_CONFIG_SHUTDOWN, 0); return regmap_update_bits(data->regmap, LM75_REG_CONF, LM75_SHUTDOWN, 0); }
--
2.43.0