[PATCH] hwmon: (nct6775) Add support for NCT5525

[PATCH] hwmon: (nct6775) Add support for NCT5525

[Anton Lundin]

Extend nct6775 driver to support NCT5525.

Assisted-by: Copilot:GPT-5.6-Terra
Signed-off-by: Anton Lundin <glance@ac2.se>
---
 .../bindings/hwmon/nuvoton,nct6775.yaml       |   1 +
 Documentation/hwmon/nct6775.rst               |  10 +-
 drivers/hwmon/nct6775-core.c                  | 130 +++++++++++++++++-
 drivers/hwmon/nct6775-i2c.c                   |   6 +-
 drivers/hwmon/nct6775-platform.c              |  12 ++
 drivers/hwmon/nct6775.h                       |   3 +-
 6 files changed, 156 insertions(+), 6 deletions(-)

diff --git a/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
index 244470282890..16c21f1f46ef 100644
--- a/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
+++ b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
@@ -25,6 +25,7 @@ properties:
       - nuvoton,nct6797
       - nuvoton,nct6798
       - nuvoton,nct6799
+      - nuvoton,nct5525
 
   reg:
     maxItems: 1
diff --git a/Documentation/hwmon/nct6775.rst b/Documentation/hwmon/nct6775.rst
index d2dedade0606..3e2992a1e24f 100644
--- a/Documentation/hwmon/nct6775.rst
+++ b/Documentation/hwmon/nct6775.rst
@@ -48,6 +48,14 @@ Supported chips:
 
     Datasheet: Available from the Nuvoton web site
 
+  * Nuvoton NCT5525D
+
+    Prefix: 'nct5525'
+
+    Addresses scanned: ISA address retrieved from Super I/O registers
+
+    Datasheet: Available from Nuvoton upon request
+
   * Nuvoton NCT5572D/NCT6771F/NCT6772F/NCT6775F/W83677HG-I
 
     Prefix: 'nct6775'
@@ -159,7 +167,7 @@ direct temperature sensor inputs, the others are special sources such as PECI,
 PCH, and SMBUS. Depending on the chip type, 2 to 6 of the temperature sources
 can be monitored and compared against minimum, maximum, and critical
 temperatures. The driver reports up to 10 of the temperatures to the user.
-There are 4 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors,
+There are 3 to 7 fan rotation speed sensors, 8 to 18 analog voltage sensors,
 one VID, alarms with beep warnings (control unimplemented), and some automatic
 fan regulation strategies (plus manual fan control mode).
 
diff --git a/drivers/hwmon/nct6775-core.c b/drivers/hwmon/nct6775-core.c
index cf27b9c7a89e..fb99bdf16764 100644
--- a/drivers/hwmon/nct6775-core.c
+++ b/drivers/hwmon/nct6775-core.c
@@ -38,6 +38,7 @@
  * nct5585d    14      7       7       2+6    0xd428 0xc1    0x5ca3
  * nct6796d-s  18      7       7       6+2    0xd801 0xc1    0x5ca3
  * nct6799d-r  18      7       7       6+2    0xd802 0xc1    0x5ca3
+ * nct5525d     8      3       2       3+3    0xd2b3 0xc1    0x5ca3
  *
  * #temp lists the number of monitored temperature sources (first value) plus
  * the number of directly connectable temperature sensors (second value).
@@ -80,6 +81,7 @@ static const char * const nct6775_device_names[] = {
 	[nct6797] = "nct6797",
 	[nct6798] = "nct6798",
 	[nct6799] = "nct6799",
+	[nct5525] = "nct5525",
 };
 
 /* Common and NCT6775 specific data */
@@ -840,6 +842,33 @@ static const u16 NCT6106_REG_TEMP_CRIT[32] = {
 
 static const u16 NCT6106_REG_TSI_TEMP[] = { 0x59, 0x5b, 0x5d, 0x5f, 0x61, 0x63, 0x65, 0x67 };
 
+/* NCT5525D specific data */
+
+static const u16 NCT5525_REG_IN_MAX[] = {
+	0x92, 0x94, 0x96, 0x9a, 0x9c, 0x9e, 0xa0, 0xa2 };
+static const u16 NCT5525_REG_IN_MIN[] = {
+	0x93, 0x95, 0x97, 0x9b, 0x9d, 0x9f, 0xa1, 0xa3 };
+static const u16 NCT5525_REG_IN[] = {
+	0x01, 0x02, 0x03, 0x05, 0x06, 0x07, 0x08, 0x09 };
+
+static const u16 NCT5525_REG_FAN[] = { 0x20, 0x22, 0x28 };
+static const u16 NCT5525_REG_FAN_MIN[] = { 0xe0, 0xe2, 0xe8 };
+static const u16 NCT5525_REG_FAN_PULSES[] = { 0xf6, 0xf6, 0xf5 };
+static const u16 NCT5525_FAN_PULSE_SHIFT[] = { 0, 2, 6 };
+
+static const s8 NCT5525_ALARM_BITS[NUM_ALARM_BITS] = {
+	 1,  2,  3,  5,  6,  7,  8,  9, -1, -1, -1, -1,	  /* in0-in11     */
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,	  /* in12-in23    */
+	32, 33, 36, -1, -1, -1, -1, -1, -1, -1, -1, -1,	  /* fan1-fan12   */
+	16, 17, 18, -1, -1, -1, -1, -1, -1, -1, -1, -1,	  /* temp1-temp12 */
+	-1, -1,						  /* intr0-intr1  */
+};
+
+static const u16 NCT5525_REG_BEEP[NUM_REG_BEEP] = { 0 };
+static const s8 NCT5525_BEEP_BITS[NUM_BEEP_BITS] = {
+	[0 ... NUM_BEEP_BITS - 1] = -1,
+};
+
 /* NCT6112D/NCT6114D/NCT6116D specific data */
 
 static const u16 NCT6116_REG_FAN[] = { 0x20, 0x22, 0x24, 0x26, 0x28 };
@@ -1034,6 +1063,10 @@ static const u16 scale_in_6126[10] = {
 	800, 800, 1600, 1600, 800, 800, 1600, 1600, 1600, 800
 };
 
+static const u16 scale_in_5525[8] = {
+	800, 1600, 1600, 800, 1600, 1600, 1600, 800
+};
+
 static inline long in_from_reg(u8 reg, u8 nr, const u16 *scales)
 {
 	return DIV_ROUND_CLOSEST(reg * scales[nr], 100);
@@ -1191,6 +1224,10 @@ bool nct6775_reg_is_word_sized(struct nct6775_data *data, u16 reg)
 		  (reg >= 0x59 && reg < 0x69 && (reg & 1)) ||
 		  reg == 0xe0 || reg == 0xe2 || reg == 0xe4 ||
 		  reg == 0x111 || reg == 0x121 || reg == 0x131;
+	case nct5525:
+		return reg == 0x20 || reg == 0x22 || reg == 0x28 ||
+		  reg == 0x59 || reg == 0x5b || reg == 0xe0 || reg == 0xe2 ||
+		  reg == 0xe8 || reg == 0x111 || reg == 0x121;
 	case nct6116:
 	case nct6126:
 		return reg == 0x20 || reg == 0x22 || reg == 0x24 ||
@@ -1574,6 +1611,7 @@ static int nct6775_update_pwm_limits(struct device *dev)
 			data->auto_pwm[i][data->auto_pwm_num] = 0xff;
 			break;
 		case nct6106:
+		case nct5525:
 		case nct6116:
 		case nct6126:
 		case nct6779:
@@ -1955,6 +1993,8 @@ static umode_t nct6775_in_is_visible(struct kobject *kobj,
 
 	if (nr == 1 && data->ALARM_BITS[in] == -1)
 		return 0;
+	if (nr == 2 && data->BEEP_BITS[in] == -1)
+		return 0;
 
 	if (!(data->have_in & BIT(in)))
 		return 0;
@@ -2398,8 +2438,12 @@ static umode_t nct6775_temp_is_visible(struct kobject *kobj,
 	if (nr == 2 && find_temp_source(data, temp, data->num_temp_alarms) < 0)
 		return 0;				/* alarm */
 
-	if (nr == 3 && find_temp_source(data, temp, data->num_temp_beeps) < 0)
-		return 0;				/* beep */
+	if (nr == 3) {
+		int source = find_temp_source(data, temp, data->num_temp_beeps);
+
+		if (source < 0 || data->BEEP_BITS[source + TEMP_ALARM_BASE] == -1)
+			return 0;			/* beep */
+	}
 
 	if (nr == 4 && !data->reg_temp[1][temp])	/* max */
 		return 0;
@@ -3240,6 +3284,7 @@ store_auto_pwm(struct device *dev, struct device_attribute *attr,
 		case nct6776:
 			break; /* always enabled, nothing to do */
 		case nct6106:
+		case nct5525:
 		case nct6116:
 		case nct6126:
 		case nct6779:
@@ -3640,6 +3685,87 @@ int nct6775_probe(struct device *dev, struct nct6775_data *data,
 		reg_temp_crit_l = NCT6106_REG_TEMP_CRIT_L;
 		reg_temp_crit_h = NCT6106_REG_TEMP_CRIT_H;
 
+		break;
+	case nct5525:
+		data->in_num = 8;
+		data->scale_in = scale_in_5525;
+		data->pwm_num = 2;
+		data->auto_pwm_num = 4;
+		data->temp_fixed_num = 3;
+		data->num_temp_alarms = 3;
+		data->num_temp_beeps = 0;
+
+		data->ALARM_BITS = NCT5525_ALARM_BITS;
+		data->BEEP_BITS = NCT5525_BEEP_BITS;
+
+		data->fan_from_reg = fan_from_reg13;
+		data->fan_from_reg_min = fan_from_reg13;
+		data->target_temp_mask = 0xff;
+		data->tolerance_mask = 0x07;
+		data->speed_tolerance_limit = 63;
+
+		data->temp_label = nct6776_temp_label;
+		data->temp_mask = NCT6776_TEMP_MASK;
+		data->virt_temp_mask = NCT6776_VIRT_TEMP_MASK;
+
+		data->REG_VBAT = NCT6106_REG_VBAT;
+		data->REG_DIODE = NCT6106_REG_DIODE;
+		data->DIODE_MASK = NCT6106_DIODE_MASK;
+		data->REG_VIN = NCT5525_REG_IN;
+		data->REG_IN_MINMAX[0] = NCT5525_REG_IN_MIN;
+		data->REG_IN_MINMAX[1] = NCT5525_REG_IN_MAX;
+		data->REG_TARGET = NCT6106_REG_TARGET;
+		data->REG_FAN = NCT5525_REG_FAN;
+		data->REG_FAN_MODE = NCT6106_REG_FAN_MODE;
+		data->REG_FAN_MIN = NCT5525_REG_FAN_MIN;
+		data->REG_FAN_PULSES = NCT5525_REG_FAN_PULSES;
+		data->FAN_PULSE_SHIFT = NCT5525_FAN_PULSE_SHIFT;
+		data->REG_FAN_TIME[0] = NCT6106_REG_FAN_STOP_TIME;
+		data->REG_FAN_TIME[1] = NCT6106_REG_FAN_STEP_UP_TIME;
+		data->REG_FAN_TIME[2] = NCT6106_REG_FAN_STEP_DOWN_TIME;
+		data->REG_TOLERANCE_H = NCT6106_REG_TOLERANCE_H;
+		data->REG_PWM[0] = NCT6116_REG_PWM;
+		data->REG_PWM[1] = NCT6106_REG_FAN_START_OUTPUT;
+		data->REG_PWM[2] = NCT6106_REG_FAN_STOP_OUTPUT;
+		data->REG_PWM[5] = NCT6106_REG_WEIGHT_DUTY_STEP;
+		data->REG_PWM[6] = NCT6106_REG_WEIGHT_DUTY_BASE;
+		data->REG_PWM_READ = NCT6106_REG_PWM_READ;
+		data->REG_PWM_MODE = NCT6106_REG_PWM_MODE;
+		data->PWM_MODE_MASK = NCT6106_PWM_MODE_MASK;
+		data->REG_AUTO_TEMP = NCT6106_REG_AUTO_TEMP;
+		data->REG_AUTO_PWM = NCT6106_REG_AUTO_PWM;
+		data->REG_CRITICAL_TEMP = NCT6106_REG_CRITICAL_TEMP;
+		data->REG_CRITICAL_TEMP_TOLERANCE
+		  = NCT6106_REG_CRITICAL_TEMP_TOLERANCE;
+		data->REG_CRITICAL_PWM_ENABLE = NCT6106_REG_CRITICAL_PWM_ENABLE;
+		data->CRITICAL_PWM_ENABLE_MASK
+		  = NCT6106_CRITICAL_PWM_ENABLE_MASK;
+		data->REG_CRITICAL_PWM = NCT6106_REG_CRITICAL_PWM;
+		data->REG_TEMP_OFFSET = NCT6106_REG_TEMP_OFFSET;
+		data->REG_TEMP_SOURCE = NCT6106_REG_TEMP_SOURCE;
+		data->REG_TEMP_SEL = NCT6116_REG_TEMP_SEL;
+		data->REG_WEIGHT_TEMP_SEL = NCT6106_REG_WEIGHT_TEMP_SEL;
+		data->REG_WEIGHT_TEMP[0] = NCT6106_REG_WEIGHT_TEMP_STEP;
+		data->REG_WEIGHT_TEMP[1] = NCT6106_REG_WEIGHT_TEMP_STEP_TOL;
+		data->REG_WEIGHT_TEMP[2] = NCT6106_REG_WEIGHT_TEMP_BASE;
+		data->REG_ALARM = NCT6106_REG_ALARM;
+		data->REG_BEEP = NCT5525_REG_BEEP;
+		data->REG_TSI_TEMP = NCT6116_REG_TSI_TEMP;
+
+		reg_temp = NCT6106_REG_TEMP;
+		reg_temp_mon = NCT6106_REG_TEMP_MON;
+		num_reg_temp = 3;
+		num_reg_temp_mon = 2;
+		num_reg_tsi_temp = ARRAY_SIZE(NCT6116_REG_TSI_TEMP);
+		reg_temp_over = NCT6106_REG_TEMP_OVER;
+		reg_temp_hyst = NCT6106_REG_TEMP_HYST;
+		reg_temp_config = NCT6106_REG_TEMP_CONFIG;
+		num_reg_temp_config = 3;
+		reg_temp_alternate = NCT6106_REG_TEMP_ALTERNATE;
+		reg_temp_crit = NCT6106_REG_TEMP_CRIT;
+		reg_temp_crit_l = NCT6106_REG_TEMP_CRIT_L;
+		reg_temp_crit_h = NCT6106_REG_TEMP_CRIT_H;
+
 		break;
 	case nct6116:
 		data->in_num = 9;
diff --git a/drivers/hwmon/nct6775-i2c.c b/drivers/hwmon/nct6775-i2c.c
index 07783910c058..3efae4bf5e4a 100644
--- a/drivers/hwmon/nct6775-i2c.c
+++ b/drivers/hwmon/nct6775-i2c.c
@@ -88,6 +88,7 @@ static const struct of_device_id __maybe_unused nct6775_i2c_of_match[] = {
 	{ .compatible = "nuvoton,nct6797", .data = (void *)nct6797, },
 	{ .compatible = "nuvoton,nct6798", .data = (void *)nct6798, },
 	{ .compatible = "nuvoton,nct6799", .data = (void *)nct6799, },
+	{ .compatible = "nuvoton,nct5525", .data = (void *)nct5525, },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, nct6775_i2c_of_match);
@@ -106,6 +107,7 @@ static const struct i2c_device_id nct6775_i2c_id[] = {
 	{ .name = "nct6797", .driver_data = nct6797 },
 	{ .name = "nct6798", .driver_data = nct6798 },
 	{ .name = "nct6799", .driver_data = nct6799 },
+	{ .name = "nct5525", .driver_data = nct5525 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, nct6775_i2c_id);
@@ -126,8 +128,8 @@ static int nct6775_i2c_probe_init(struct nct6775_data *data)
 	 * controlling/monitoring the fans -- these are thus unlikely to be
 	 * doing anything actually useful.
 	 */
-	data->has_fan = 0x03;
-	data->has_fan_min = 0x03;
+	data->has_fan = data->kind == nct5525 ? 0x07 : 0x03;
+	data->has_fan_min = data->has_fan;
 	data->has_pwm = 0x03;
 
 	/*
diff --git a/drivers/hwmon/nct6775-platform.c b/drivers/hwmon/nct6775-platform.c
index d359c28f3e0f..3bc7a27d58a6 100644
--- a/drivers/hwmon/nct6775-platform.c
+++ b/drivers/hwmon/nct6775-platform.c
@@ -37,6 +37,7 @@ static const char * const nct6775_sio_names[] __initconst = {
 	[nct6797] = "NCT6797D",
 	[nct6798] = "NCT6798D/NCT5585D",
 	[nct6799] = "NCT6796D-S/NCT6799D-R",
+	[nct5525] = "NCT5525D",
 };
 
 static unsigned short force_id;
@@ -91,6 +92,7 @@ MODULE_PARM_DESC(fan_debounce, "Enable debouncing for fan RPM signal");
 #define SIO_NCT6797_ID		0xd450
 #define SIO_NCT6798_ID		0xd428
 #define SIO_NCT6799_ID		0xd800
+#define SIO_NCT5525_ID		0xd2b0
 #define SIO_ID_MASK		0xFFF8
 
 /*
@@ -552,6 +554,8 @@ nct6775_check_fan_inputs(struct nct6775_data *data, struct nct6775_sio_data *sio
 
 		fan3pin = !(cr24 & 0x80);
 		pwm3pin = cr24 & 0x08;
+	} else if (data->kind == nct5525) {
+		fan3pin = true;
 	} else if (data->kind == nct6116) {
 		int cr1a = sio_data->sio_inb(sio_data, 0x1a);
 		int cr1b = sio_data->sio_inb(sio_data, 0x1b);
@@ -839,6 +843,8 @@ static umode_t nct6775_other_is_visible(struct kobject *kobj,
 		if (data->BEEP_BITS[INTRUSION_ALARM_BASE + index - 3] < 0)
 			return 0;
 	}
+	if (index == 5 && data->BEEP_BITS[BEEP_ENABLE_BASE] < 0)
+		return 0;
 
 	return nct6775_attr_mode(data, attr);
 }
@@ -883,6 +889,7 @@ static int nct6775_platform_probe_init(struct nct6775_data *data)
 		data->have_vid = (cr2a & 0x60) == 0x40;
 		break;
 	case nct6106:
+	case nct5525:
 	case nct6116:
 	case nct6126:
 	case nct6779:
@@ -919,6 +926,8 @@ static int nct6775_platform_probe_init(struct nct6775_data *data)
 		case nct6126:
 			tmp |= 0xe0;
 			break;
+		case nct5525:
+			break;
 		case nct6775:
 			tmp |= 0x1e;
 			break;
@@ -1072,6 +1081,9 @@ static int __init nct6775_find(int sioaddr, struct nct6775_sio_data *sio_data)
 	case SIO_NCT6799_ID:
 		sio_data->kind = nct6799;
 		break;
+	case SIO_NCT5525_ID:
+		sio_data->kind = nct5525;
+		break;
 	default:
 		if (val != 0xffff)
 			pr_debug("unsupported chip ID: 0x%04x\n", val);
diff --git a/drivers/hwmon/nct6775.h b/drivers/hwmon/nct6775.h
index d18ac91be497..d94a1c1a31f5 100644
--- a/drivers/hwmon/nct6775.h
+++ b/drivers/hwmon/nct6775.h
@@ -5,7 +5,8 @@
 #include <linux/types.h>
 
 enum kinds { nct6106, nct6116, nct6126, nct6775, nct6776, nct6779, nct6791,
-	     nct6792, nct6793, nct6795, nct6796, nct6797, nct6798, nct6799 };
+	     nct6792, nct6793, nct6795, nct6796, nct6797, nct6798, nct6799,
+	     nct5525 };
 enum pwm_enable { off, manual, thermal_cruise, speed_cruise, sf3, sf4 };
 
 #define NUM_TEMP	12	/* Max number of temp attribute sets w/ limits*/
-- 
2.47.3

Re: [PATCH] hwmon: (nct6775) Add support for NCT5525

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] hwmon: (nct6775) nct6775_reg_is_word_sized() corrupts NCT5525 target regs
- [Low] hwmon: (nct6775) no-op fan_debounce handling in nct6775_platform_probe_init()
--

commit b2c50b829c2c187ba7bd478ebf5b2095ec0b4f6d
Author: Anton Lundin <glance@ac2.se>

hwmon: (nct6775) Add support for NCT5525

This commit adds hardware monitoring support for the Nuvoton NCT5525D
chip to the nct6775 core, platform, and i2c drivers, as well as the
device tree bindings and documentation.

> diff --git a/drivers/hwmon/nct6775-core.c b/drivers/hwmon/nct6775-core.c
> index cf27b9c7a89ed..fb99bdf16764a 100644
> --- a/drivers/hwmon/nct6775-core.c
> +++ b/drivers/hwmon/nct6775-core.c

[ ... ]

> @@ -1191,6 +1224,10 @@ bool nct6775_reg_is_word_sized(struct nct6775_data *data, u16 reg)
>  		  (reg >= 0x59 && reg < 0x69 && (reg & 1)) ||
>  		  reg == 0xe0 || reg == 0xe2 || reg == 0xe4 ||
>  		  reg == 0x111 || reg == 0x121 || reg == 0x131;
> +	case nct5525:
> +		return reg == 0x20 || reg == 0x22 || reg == 0x28 ||
> +		  reg == 0x59 || reg == 0x5b || reg == 0xe0 || reg == 0xe2 ||
> +		  reg == 0xe8 || reg == 0x111 || reg == 0x121;

[Severity: Medium]
Should registers 0x111 and 0x121 be marked as word-sized in
nct6775_reg_is_word_sized() for nct5525?

In drivers/hwmon/nct6775-core.c, nct6775_probe() configures nct5525 with:

	data->target_temp_mask = 0xff;
	data->REG_TARGET = NCT6106_REG_TARGET;
	data->REG_TOLERANCE_H = NCT6106_REG_TOLERANCE_H;

where NCT6106_REG_TARGET is { 0x111, 0x121, 0x131 } and
NCT6106_REG_TOLERANCE_H is { 0x112, 0x122, 0x132 }.

When 0x111 and 0x121 are marked as word-sized, nct6775_read_value() performs
a 16-bit big-endian read across reg (high byte) and reg + 1 (low byte), and
nct6775_write_value() writes value >> 8 to reg and value & 0xff to reg + 1.

However, nct6775_update_pwm_limits() and pwm_update_registers() treat
REG_TARGET and REG_TOLERANCE_H as separate 8-bit registers:

drivers/hwmon/nct6775-core.c:nct6775_update_pwm_limits() {
	...
	err = nct6775_read_value(data, data->REG_TARGET[i], &reg_t);
	if (err)
		return err;

	/* Update only in matching mode or if never updated */
	if (!data->target_temp[i] ||
	    data->pwm_enable[i] == thermal_cruise)
		data->target_temp[i] = reg_t & data->target_temp_mask;
	if (!data->target_speed[i] ||
	    data->pwm_enable[i] == speed_cruise) {
		if (data->REG_TOLERANCE_H) {
			err = nct6775_read_value(data, data->REG_TOLERANCE_H[i], &reg);
			if (err)
				return err;
			reg_t |= (reg & 0x0f) << 8;
		}
		data->target_speed[i] = reg_t;
	}
	...
}

And on write in pwm_update_registers():

drivers/hwmon/nct6775-core.c:pwm_update_registers() {
	...
	case speed_cruise:
		err = nct6775_write_value(data, data->REG_TARGET[nr],
					  data->target_speed[nr] & 0xff);
		...
	case thermal_cruise:
		err = nct6775_write_value(data, data->REG_TARGET[nr], data->target_temp[nr]);
	...
}

Because REG_TARGET[i] is read as a 16-bit big-endian value spanning 0x111
and 0x112, masking reg_t with target_temp_mask (0xff) discards byte 0x111
and reads byte 0x112 (REG_TOLERANCE_H) as the target temperature. Similarly,
writing an 8-bit value to REG_TARGET[nr] in pwm_update_registers() writes
0x00 to 0x111/0x121 and overwrites 0x112/0x122 with the low byte.

> diff --git a/drivers/hwmon/nct6775-platform.c b/drivers/hwmon/nct6775-platform.c
> index d359c28f3e0f3..3bc7a27d58a60 100644
> --- a/drivers/hwmon/nct6775-platform.c
> +++ b/drivers/hwmon/nct6775-platform.c

[ ... ]

> @@ -919,6 +926,8 @@ static int nct6775_platform_probe_init(struct nct6775_data *data)
>  		case nct6126:
>  			tmp |= 0xe0;
>  			break;
> +		case nct5525:
> +			break;
>  		case nct6775:
>  			tmp |= 0x1e;
>  			break;

[Severity: Low]
In drivers/hwmon/nct6775-platform.c, when fan_debounce is enabled in
nct6775_platform_probe_init(), the nct5525 case breaks without setting any
bits in tmp, and then falls through to write the unchanged tmp value back to
NCT6775_REG_CR_FAN_DEBOUNCE and log "Enabled fan debounce for chip ...":

drivers/hwmon/nct6775-platform.c:nct6775_platform_probe_init() {
	...
		sio_data->sio_outb(sio_data, NCT6775_REG_CR_FAN_DEBOUNCE,
			     tmp);
		pr_info("Enabled fan debounce for chip %s\n", data->name);
	}
}

Should nct5525 either set the appropriate debounce bits in tmp or skip
writing NCT6775_REG_CR_FAN_DEBOUNCE and logging that fan debounce was
enabled?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261103132948.144216-1-glance@ac2.se?part=1

Re: [PATCH] hwmon: (nct6775) Add support for NCT5525

[Krzysztof Kozlowski]

On 03/11/2026 14:29, Anton Lundin wrote:
> Extend nct6775 driver to support NCT5525.
> 
> Assisted-by: Copilot:GPT-5.6-Terra

Please run scripts/checkpatch.pl on the patches and fix reported
warnings. After that, run also 'scripts/checkpatch.pl --strict' on the
patches and (probably) fix more warnings. Some warnings can be ignored,
especially from --strict run, but the code here looks like it needs a
fix. Feel free to get in touch if the warning is not clear.


> Signed-off-by: Anton Lundin <glance@ac2.se>
> ---
>  .../bindings/hwmon/nuvoton,nct6775.yaml       |   1 +

Please use scripts/get_maintainers.pl to get a list of necessary people
and lists to CC. It might happen, that command when run on an older
kernel, gives you outdated entries. Therefore please be sure you base
your patches on recent Linux kernel.

Tools like b4 or scripts/get_maintainer.pl provide you proper list of
people, so fix your workflow. Tools might also fail if you work on some
ancient tree (don't, instead use mainline) or work on fork of kernel
(don't, instead use mainline). Just use b4 and everything should be
fine, although remember about `b4 prep --auto-to-cc` if you added new
patches to the patchset.

You missed at least devicetree list (maybe more), so this won't be
tested by automated tooling. Performing review on untested code might be
a waste of time.

Please kindly resend and include all necessary To/Cc entries.


>  Documentation/hwmon/nct6775.rst               |  10 +-
>  drivers/hwmon/nct6775-core.c                  | 130 +++++++++++++++++-
>  drivers/hwmon/nct6775-i2c.c                   |   6 +-
>  drivers/hwmon/nct6775-platform.c              |  12 ++
>  drivers/hwmon/nct6775.h                       |   3 +-
>  6 files changed, 156 insertions(+), 6 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
> index 244470282890..16c21f1f46ef 100644
> --- a/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
> +++ b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
> @@ -25,6 +25,7 @@ properties:
>        - nuvoton,nct6797
>        - nuvoton,nct6798
>        - nuvoton,nct6799
> +      - nuvoton,nct5525

Also, to spare you one review cycle - don't break the order.


Best regards,
Krzysztof

Re: [PATCH] hwmon: (nct6775) Add support for NCT5525

[Guenter Roeck]

On 11/3/26 05:29, Anton Lundin wrote:
> Extend nct6775 driver to support NCT5525.
> 
> Assisted-by: Copilot:GPT-5.6-Terra
> Signed-off-by: Anton Lundin <glance@ac2.se>


I don't havea datasheet for this chip, but I do have to say
that this seems to be off just form chip numbering perspective.
 From the registers it looks like the chip is mostly compatible
with the NCT61xx series, but NCT55xx chips are typically scaled-down
variants of MCT67xx series chips. I _will_ need to see a datasheet
to confirm, or at the very least independent confirmation that the
driver is correct.

Some more comments inline.

> ---
>   .../bindings/hwmon/nuvoton,nct6775.yaml       |   1 +
>   Documentation/hwmon/nct6775.rst               |  10 +-
>   drivers/hwmon/nct6775-core.c                  | 130 +++++++++++++++++-
>   drivers/hwmon/nct6775-i2c.c                   |   6 +-
>   drivers/hwmon/nct6775-platform.c              |  12 ++
>   drivers/hwmon/nct6775.h                       |   3 +-
>   6 files changed, 156 insertions(+), 6 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
> index 244470282890..16c21f1f46ef 100644
> --- a/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
> +++ b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
> @@ -25,6 +25,7 @@ properties:
>         - nuvoton,nct6797
>         - nuvoton,nct6798
>         - nuvoton,nct6799
> +      - nuvoton,nct5525
>   
>     reg:
>       maxItems: 1
> diff --git a/Documentation/hwmon/nct6775.rst b/Documentation/hwmon/nct6775.rst
> index d2dedade0606..3e2992a1e24f 100644
> --- a/Documentation/hwmon/nct6775.rst
> +++ b/Documentation/hwmon/nct6775.rst
> @@ -48,6 +48,14 @@ Supported chips:
>   
>       Datasheet: Available from the Nuvoton web site
>   
> +  * Nuvoton NCT5525D
> +
> +    Prefix: 'nct5525'
> +
> +    Addresses scanned: ISA address retrieved from Super I/O registers
> +
> +    Datasheet: Available from Nuvoton upon request
> +
>     * Nuvoton NCT5572D/NCT6771F/NCT6772F/NCT6775F/W83677HG-I
>   
>       Prefix: 'nct6775'
> @@ -159,7 +167,7 @@ direct temperature sensor inputs, the others are special sources such as PECI,
>   PCH, and SMBUS. Depending on the chip type, 2 to 6 of the temperature sources
>   can be monitored and compared against minimum, maximum, and critical
>   temperatures. The driver reports up to 10 of the temperatures to the user.
> -There are 4 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors,
> +There are 3 to 7 fan rotation speed sensors, 8 to 18 analog voltage sensors,
>   one VID, alarms with beep warnings (control unimplemented), and some automatic
>   fan regulation strategies (plus manual fan control mode).
>   
> diff --git a/drivers/hwmon/nct6775-core.c b/drivers/hwmon/nct6775-core.c
> index cf27b9c7a89e..fb99bdf16764 100644
> --- a/drivers/hwmon/nct6775-core.c
> +++ b/drivers/hwmon/nct6775-core.c
> @@ -38,6 +38,7 @@
>    * nct5585d    14      7       7       2+6    0xd428 0xc1    0x5ca3
>    * nct6796d-s  18      7       7       6+2    0xd801 0xc1    0x5ca3
>    * nct6799d-r  18      7       7       6+2    0xd802 0xc1    0x5ca3
> + * nct5525d     8      3       2       3+3    0xd2b3 0xc1    0x5ca3

Alphabetic order (unless associated with another chip).

>    *
>    * #temp lists the number of monitored temperature sources (first value) plus
>    * the number of directly connectable temperature sensors (second value).
> @@ -80,6 +81,7 @@ static const char * const nct6775_device_names[] = {
>   	[nct6797] = "nct6797",
>   	[nct6798] = "nct6798",
>   	[nct6799] = "nct6799",
> +	[nct5525] = "nct5525",

Alphabetic order.

>   };
>   
>   /* Common and NCT6775 specific data */
> @@ -840,6 +842,33 @@ static const u16 NCT6106_REG_TEMP_CRIT[32] = {
>   
>   static const u16 NCT6106_REG_TSI_TEMP[] = { 0x59, 0x5b, 0x5d, 0x5f, 0x61, 0x63, 0x65, 0x67 };
>   
> +/* NCT5525D specific data */
> +
> +static const u16 NCT5525_REG_IN_MAX[] = {
> +	0x92, 0x94, 0x96, 0x9a, 0x9c, 0x9e, 0xa0, 0xa2 };
> +static const u16 NCT5525_REG_IN_MIN[] = {
> +	0x93, 0x95, 0x97, 0x9b, 0x9d, 0x9f, 0xa1, 0xa3 };
> +static const u16 NCT5525_REG_IN[] = {
> +	0x01, 0x02, 0x03, 0x05, 0x06, 0x07, 0x08, 0x09 };
> +

The above are equivalent to the NCT6106 definitions.
Please do not duplicate definitions unless necessary.

> +static const u16 NCT5525_REG_FAN[] = { 0x20, 0x22, 0x28 };
> +static const u16 NCT5525_REG_FAN_MIN[] = { 0xe0, 0xe2, 0xe8 };
> +static const u16 NCT5525_REG_FAN_PULSES[] = { 0xf6, 0xf6, 0xf5 };
> +static const u16 NCT5525_FAN_PULSE_SHIFT[] = { 0, 2, 6 };
> +

This suggests compatibility with NCT6116, with fans index 2 and 3 not populated.
Would it be possible to model it that way ?

> +static const s8 NCT5525_ALARM_BITS[NUM_ALARM_BITS] = {
> +	 1,  2,  3,  5,  6,  7,  8,  9, -1, -1, -1, -1,	  /* in0-in11     */
> +	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,	  /* in12-in23    */
> +	32, 33, 36, -1, -1, -1, -1, -1, -1, -1, -1, -1,	  /* fan1-fan12   */
> +	16, 17, 18, -1, -1, -1, -1, -1, -1, -1, -1, -1,	  /* temp1-temp12 */
> +	-1, -1,						  /* intr0-intr1  */
> +};
> +
> +static const u16 NCT5525_REG_BEEP[NUM_REG_BEEP] = { 0 };
> +static const s8 NCT5525_BEEP_BITS[NUM_BEEP_BITS] = {
> +	[0 ... NUM_BEEP_BITS - 1] = -1,
> +};
> +
>   /* NCT6112D/NCT6114D/NCT6116D specific data */
>   
>   static const u16 NCT6116_REG_FAN[] = { 0x20, 0x22, 0x24, 0x26, 0x28 };
> @@ -1034,6 +1063,10 @@ static const u16 scale_in_6126[10] = {
>   	800, 800, 1600, 1600, 800, 800, 1600, 1600, 1600, 800
>   };
>   
> +static const u16 scale_in_5525[8] = {
> +	800, 1600, 1600, 800, 1600, 1600, 1600, 800
> +};
> +
>   static inline long in_from_reg(u8 reg, u8 nr, const u16 *scales)
>   {
>   	return DIV_ROUND_CLOSEST(reg * scales[nr], 100);
> @@ -1191,6 +1224,10 @@ bool nct6775_reg_is_word_sized(struct nct6775_data *data, u16 reg)
>   		  (reg >= 0x59 && reg < 0x69 && (reg & 1)) ||
>   		  reg == 0xe0 || reg == 0xe2 || reg == 0xe4 ||
>   		  reg == 0x111 || reg == 0x121 || reg == 0x131;
> +	case nct5525:
> +		return reg == 0x20 || reg == 0x22 || reg == 0x28 ||
> +		  reg == 0x59 || reg == 0x5b || reg == 0xe0 || reg == 0xe2 ||
> +		  reg == 0xe8 || reg == 0x111 || reg == 0x121;

Sashiko has some valid concerns here.

>   	case nct6116:
>   	case nct6126:
>   		return reg == 0x20 || reg == 0x22 || reg == 0x24 ||
> @@ -1574,6 +1611,7 @@ static int nct6775_update_pwm_limits(struct device *dev)
>   			data->auto_pwm[i][data->auto_pwm_num] = 0xff;
>   			break;
>   		case nct6106:
> +		case nct5525:
>   		case nct6116:
>   		case nct6126:
>   		case nct6779:
> @@ -1955,6 +1993,8 @@ static umode_t nct6775_in_is_visible(struct kobject *kobj,
>   
>   	if (nr == 1 && data->ALARM_BITS[in] == -1)
>   		return 0;
> +	if (nr == 2 && data->BEEP_BITS[in] == -1)
> +		return 0;

This seems to be unrelated to this chip. Please do not make unrelated changes.

>   
>   	if (!(data->have_in & BIT(in)))
>   		return 0;
> @@ -2398,8 +2438,12 @@ static umode_t nct6775_temp_is_visible(struct kobject *kobj,
>   	if (nr == 2 && find_temp_source(data, temp, data->num_temp_alarms) < 0)
>   		return 0;				/* alarm */
>   
> -	if (nr == 3 && find_temp_source(data, temp, data->num_temp_beeps) < 0)
> -		return 0;				/* beep */
> +	if (nr == 3) {
> +		int source = find_temp_source(data, temp, data->num_temp_beeps);
> +
> +		if (source < 0 || data->BEEP_BITS[source + TEMP_ALARM_BASE] == -1)
> +			return 0;			/* beep */
> +	}

Same as above.

>   
>   	if (nr == 4 && !data->reg_temp[1][temp])	/* max */
>   		return 0;
> @@ -3240,6 +3284,7 @@ store_auto_pwm(struct device *dev, struct device_attribute *attr,
>   		case nct6776:
>   			break; /* always enabled, nothing to do */
>   		case nct6106:
> +		case nct5525:
>   		case nct6116:
>   		case nct6126:
>   		case nct6779:
> @@ -3640,6 +3685,87 @@ int nct6775_probe(struct device *dev, struct nct6775_data *data,
>   		reg_temp_crit_l = NCT6106_REG_TEMP_CRIT_L;
>   		reg_temp_crit_h = NCT6106_REG_TEMP_CRIT_H;
>   
> +		break;
> +	case nct5525:
> +		data->in_num = 8;
> +		data->scale_in = scale_in_5525;
> +		data->pwm_num = 2;
> +		data->auto_pwm_num = 4;
> +		data->temp_fixed_num = 3;
> +		data->num_temp_alarms = 3;
> +		data->num_temp_beeps = 0;
> +
> +		data->ALARM_BITS = NCT5525_ALARM_BITS;
> +		data->BEEP_BITS = NCT5525_BEEP_BITS;
> +
> +		data->fan_from_reg = fan_from_reg13;
> +		data->fan_from_reg_min = fan_from_reg13;
> +		data->target_temp_mask = 0xff;
> +		data->tolerance_mask = 0x07;
> +		data->speed_tolerance_limit = 63;
> +
> +		data->temp_label = nct6776_temp_label;
> +		data->temp_mask = NCT6776_TEMP_MASK;
> +		data->virt_temp_mask = NCT6776_VIRT_TEMP_MASK;
> +
> +		data->REG_VBAT = NCT6106_REG_VBAT;
> +		data->REG_DIODE = NCT6106_REG_DIODE;
> +		data->DIODE_MASK = NCT6106_DIODE_MASK;
> +		data->REG_VIN = NCT5525_REG_IN;
> +		data->REG_IN_MINMAX[0] = NCT5525_REG_IN_MIN;
> +		data->REG_IN_MINMAX[1] = NCT5525_REG_IN_MAX;
> +		data->REG_TARGET = NCT6106_REG_TARGET;
> +		data->REG_FAN = NCT5525_REG_FAN;
> +		data->REG_FAN_MODE = NCT6106_REG_FAN_MODE;
> +		data->REG_FAN_MIN = NCT5525_REG_FAN_MIN;
> +		data->REG_FAN_PULSES = NCT5525_REG_FAN_PULSES;
> +		data->FAN_PULSE_SHIFT = NCT5525_FAN_PULSE_SHIFT;
> +		data->REG_FAN_TIME[0] = NCT6106_REG_FAN_STOP_TIME;
> +		data->REG_FAN_TIME[1] = NCT6106_REG_FAN_STEP_UP_TIME;
> +		data->REG_FAN_TIME[2] = NCT6106_REG_FAN_STEP_DOWN_TIME;
> +		data->REG_TOLERANCE_H = NCT6106_REG_TOLERANCE_H;
> +		data->REG_PWM[0] = NCT6116_REG_PWM;
> +		data->REG_PWM[1] = NCT6106_REG_FAN_START_OUTPUT;
> +		data->REG_PWM[2] = NCT6106_REG_FAN_STOP_OUTPUT;
> +		data->REG_PWM[5] = NCT6106_REG_WEIGHT_DUTY_STEP;
> +		data->REG_PWM[6] = NCT6106_REG_WEIGHT_DUTY_BASE;
> +		data->REG_PWM_READ = NCT6106_REG_PWM_READ;
> +		data->REG_PWM_MODE = NCT6106_REG_PWM_MODE;
> +		data->PWM_MODE_MASK = NCT6106_PWM_MODE_MASK;
> +		data->REG_AUTO_TEMP = NCT6106_REG_AUTO_TEMP;
> +		data->REG_AUTO_PWM = NCT6106_REG_AUTO_PWM;
> +		data->REG_CRITICAL_TEMP = NCT6106_REG_CRITICAL_TEMP;
> +		data->REG_CRITICAL_TEMP_TOLERANCE
> +		  = NCT6106_REG_CRITICAL_TEMP_TOLERANCE;
> +		data->REG_CRITICAL_PWM_ENABLE = NCT6106_REG_CRITICAL_PWM_ENABLE;
> +		data->CRITICAL_PWM_ENABLE_MASK
> +		  = NCT6106_CRITICAL_PWM_ENABLE_MASK;
> +		data->REG_CRITICAL_PWM = NCT6106_REG_CRITICAL_PWM;
> +		data->REG_TEMP_OFFSET = NCT6106_REG_TEMP_OFFSET;
> +		data->REG_TEMP_SOURCE = NCT6106_REG_TEMP_SOURCE;
> +		data->REG_TEMP_SEL = NCT6116_REG_TEMP_SEL;
> +		data->REG_WEIGHT_TEMP_SEL = NCT6106_REG_WEIGHT_TEMP_SEL;
> +		data->REG_WEIGHT_TEMP[0] = NCT6106_REG_WEIGHT_TEMP_STEP;
> +		data->REG_WEIGHT_TEMP[1] = NCT6106_REG_WEIGHT_TEMP_STEP_TOL;
> +		data->REG_WEIGHT_TEMP[2] = NCT6106_REG_WEIGHT_TEMP_BASE;
> +		data->REG_ALARM = NCT6106_REG_ALARM;
> +		data->REG_BEEP = NCT5525_REG_BEEP;
> +		data->REG_TSI_TEMP = NCT6116_REG_TSI_TEMP;
> +
> +		reg_temp = NCT6106_REG_TEMP;
> +		reg_temp_mon = NCT6106_REG_TEMP_MON;
> +		num_reg_temp = 3;
> +		num_reg_temp_mon = 2;
> +		num_reg_tsi_temp = ARRAY_SIZE(NCT6116_REG_TSI_TEMP);
> +		reg_temp_over = NCT6106_REG_TEMP_OVER;
> +		reg_temp_hyst = NCT6106_REG_TEMP_HYST;
> +		reg_temp_config = NCT6106_REG_TEMP_CONFIG;
> +		num_reg_temp_config = 3;
> +		reg_temp_alternate = NCT6106_REG_TEMP_ALTERNATE;
> +		reg_temp_crit = NCT6106_REG_TEMP_CRIT;
> +		reg_temp_crit_l = NCT6106_REG_TEMP_CRIT_L;
> +		reg_temp_crit_h = NCT6106_REG_TEMP_CRIT_H;
> +
>   		break;
>   	case nct6116:
>   		data->in_num = 9;
> diff --git a/drivers/hwmon/nct6775-i2c.c b/drivers/hwmon/nct6775-i2c.c
> index 07783910c058..3efae4bf5e4a 100644
> --- a/drivers/hwmon/nct6775-i2c.c
> +++ b/drivers/hwmon/nct6775-i2c.c
> @@ -88,6 +88,7 @@ static const struct of_device_id __maybe_unused nct6775_i2c_of_match[] = {
>   	{ .compatible = "nuvoton,nct6797", .data = (void *)nct6797, },
>   	{ .compatible = "nuvoton,nct6798", .data = (void *)nct6798, },
>   	{ .compatible = "nuvoton,nct6799", .data = (void *)nct6799, },
> +	{ .compatible = "nuvoton,nct5525", .data = (void *)nct5525, },

Alphabetic order, please. Everywhere, even if not explicitly mentioned.>   	{ },
>   };
>   MODULE_DEVICE_TABLE(of, nct6775_i2c_of_match);
> @@ -106,6 +107,7 @@ static const struct i2c_device_id nct6775_i2c_id[] = {
>   	{ .name = "nct6797", .driver_data = nct6797 },
>   	{ .name = "nct6798", .driver_data = nct6798 },
>   	{ .name = "nct6799", .driver_data = nct6799 },
> +	{ .name = "nct5525", .driver_data = nct5525 },

Alphabetic order, please.

>   	{ }
>   };
>   MODULE_DEVICE_TABLE(i2c, nct6775_i2c_id);
> @@ -126,8 +128,8 @@ static int nct6775_i2c_probe_init(struct nct6775_data *data)
>   	 * controlling/monitoring the fans -- these are thus unlikely to be
>   	 * doing anything actually useful.
>   	 */
> -	data->has_fan = 0x03;
> -	data->has_fan_min = 0x03;
> +	data->has_fan = data->kind == nct5525 ? 0x07 : 0x03;
> +	data->has_fan_min = data->has_fan;
>   	data->has_pwm = 0x03;
>   
>   	/*
> diff --git a/drivers/hwmon/nct6775-platform.c b/drivers/hwmon/nct6775-platform.c
> index d359c28f3e0f..3bc7a27d58a6 100644
> --- a/drivers/hwmon/nct6775-platform.c
> +++ b/drivers/hwmon/nct6775-platform.c
> @@ -37,6 +37,7 @@ static const char * const nct6775_sio_names[] __initconst = {
>   	[nct6797] = "NCT6797D",
>   	[nct6798] = "NCT6798D/NCT5585D",
>   	[nct6799] = "NCT6796D-S/NCT6799D-R",
> +	[nct5525] = "NCT5525D",

Please retain alphabetic order.

>   };
>   
>   static unsigned short force_id;
> @@ -91,6 +92,7 @@ MODULE_PARM_DESC(fan_debounce, "Enable debouncing for fan RPM signal");
>   #define SIO_NCT6797_ID		0xd450
>   #define SIO_NCT6798_ID		0xd428
>   #define SIO_NCT6799_ID		0xd800
> +#define SIO_NCT5525_ID		0xd2b0
>   #define SIO_ID_MASK		0xFFF8
>   
>   /*
> @@ -552,6 +554,8 @@ nct6775_check_fan_inputs(struct nct6775_data *data, struct nct6775_sio_data *sio
>   
>   		fan3pin = !(cr24 & 0x80);
>   		pwm3pin = cr24 & 0x08;
> +	} else if (data->kind == nct5525) {
> +		fan3pin = true;
>   	} else if (data->kind == nct6116) {
>   		int cr1a = sio_data->sio_inb(sio_data, 0x1a);
>   		int cr1b = sio_data->sio_inb(sio_data, 0x1b);
> @@ -839,6 +843,8 @@ static umode_t nct6775_other_is_visible(struct kobject *kobj,
>   		if (data->BEEP_BITS[INTRUSION_ALARM_BASE + index - 3] < 0)
>   			return 0;
>   	}
> +	if (index == 5 && data->BEEP_BITS[BEEP_ENABLE_BASE] < 0)
> +		return 0;

That again seems to be unrelated to adding support for a new chip.>
>   	return nct6775_attr_mode(data, attr);
>   }
> @@ -883,6 +889,7 @@ static int nct6775_platform_probe_init(struct nct6775_data *data)
>   		data->have_vid = (cr2a & 0x60) == 0x40;
>   		break;
>   	case nct6106:
> +	case nct5525:
>   	case nct6116:
>   	case nct6126:
>   	case nct6779:
> @@ -919,6 +926,8 @@ static int nct6775_platform_probe_init(struct nct6775_data *data)
>   		case nct6126:
>   			tmp |= 0xe0;
>   			break;
> +		case nct5525:
> +			break;

Why set fan_debounce if the chip does not support it ?

>   		case nct6775:
>   			tmp |= 0x1e;
>   			break;
> @@ -1072,6 +1081,9 @@ static int __init nct6775_find(int sioaddr, struct nct6775_sio_data *sio_data)
>   	case SIO_NCT6799_ID:
>   		sio_data->kind = nct6799;
>   		break;
> +	case SIO_NCT5525_ID:
> +		sio_data->kind = nct5525;
> +		break;
>   	default:
>   		if (val != 0xffff)
>   			pr_debug("unsupported chip ID: 0x%04x\n", val);
> diff --git a/drivers/hwmon/nct6775.h b/drivers/hwmon/nct6775.h
> index d18ac91be497..d94a1c1a31f5 100644
> --- a/drivers/hwmon/nct6775.h
> +++ b/drivers/hwmon/nct6775.h
> @@ -5,7 +5,8 @@
>   #include <linux/types.h>
>   
>   enum kinds { nct6106, nct6116, nct6126, nct6775, nct6776, nct6779, nct6791,
> -	     nct6792, nct6793, nct6795, nct6796, nct6797, nct6798, nct6799 };
> +	     nct6792, nct6793, nct6795, nct6796, nct6797, nct6798, nct6799,
> +	     nct5525 };

Again, please retain alphabetic order.

>   enum pwm_enable { off, manual, thermal_cruise, speed_cruise, sf3, sf4 };
>   
>   #define NUM_TEMP	12	/* Max number of temp attribute sets w/ limits*/

Re: [PATCH] hwmon: (nct6775) Add support for NCT5525

[Anton Lundin]

On 03 november, 2026 - Guenter Roeck wrote:

> On 11/3/26 05:29, Anton Lundin wrote:
> > Extend nct6775 driver to support NCT5525.
> > 
> > Assisted-by: Copilot:GPT-5.6-Terra
> > Signed-off-by: Anton Lundin <glance@ac2.se>
> 
> 
> I don't havea datasheet for this chip, but I do have to say
> that this seems to be off just form chip numbering perspective.
> From the registers it looks like the chip is mostly compatible
> with the NCT61xx series, but NCT55xx chips are typically scaled-down
> variants of MCT67xx series chips.

Yes, its quite close. My first quick-n-dirty stab in the dark was to
just alias it to NCT6116, and that worked surprisingly well.

> I _will_ need to see a datasheet
> to confirm, or at the very least independent confirmation that the
> driver is correct.

I have a datasheet which I could send you if you'd like, or if you
rather request it yourself from Nuvoton.

> Some more comments inline.

i'll go through it and send a v2.

> > --- a/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
> > +++ b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
> > @@ -25,6 +25,7 @@ properties:
> >         - nuvoton,nct6797
> >         - nuvoton,nct6798
> >         - nuvoton,nct6799
> > +      - nuvoton,nct5525

I mostly added devicetree bindings because I saw that all the other
variants the driver supports had them, but then I noticed that nct6126
was missing.

I won't consume the devicetree bindings, so should I rather leave that
out until there's a consumer for it?


//Anton

Re: [PATCH] hwmon: (nct6775) Add support for NCT5525

[Guenter Roeck]

On 11/3/26 09:33, Anton Lundin wrote:
> On 03 november, 2026 - Guenter Roeck wrote:
> 
>> On 11/3/26 05:29, Anton Lundin wrote:
>>> Extend nct6775 driver to support NCT5525.
>>>
>>> Assisted-by: Copilot:GPT-5.6-Terra
>>> Signed-off-by: Anton Lundin <glance@ac2.se>
>>
>>
>> I don't havea datasheet for this chip, but I do have to say
>> that this seems to be off just form chip numbering perspective.
>>  From the registers it looks like the chip is mostly compatible
>> with the NCT61xx series, but NCT55xx chips are typically scaled-down
>> variants of MCT67xx series chips.
> 
> Yes, its quite close. My first quick-n-dirty stab in the dark was to
> just alias it to NCT6116, and that worked surprisingly well.
> 
>> I _will_ need to see a datasheet
>> to confirm, or at the very least independent confirmation that the
>> driver is correct.
> 
> I have a datasheet which I could send you if you'd like, or if you
> rather request it yourself from Nuvoton.
> 

It would be great if you can send it to me. I tried, but never got
through to them. The form just did not work for some reason.

>> Some more comments inline.
> 
> i'll go through it and send a v2.
> 
>>> --- a/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
>>> +++ b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
>>> @@ -25,6 +25,7 @@ properties:
>>>          - nuvoton,nct6797
>>>          - nuvoton,nct6798
>>>          - nuvoton,nct6799
>>> +      - nuvoton,nct5525
> 
> I mostly added devicetree bindings because I saw that all the other
> variants the driver supports had them, but then I noticed that nct6126
> was missing.
> 
> I won't consume the devicetree bindings, so should I rather leave that
> out until there's a consumer for it?
> 

Your call, really. If you add it, it will have to be a separate patch.

Guenter

Re: [PATCH] hwmon: (nct6775) Add support for NCT5525

[Guenter Roeck]

On 11/3/26 05:29, Anton Lundin wrote:
> Extend nct6775 driver to support NCT5525.
> 
> Assisted-by: Copilot:GPT-5.6-Terra
> Signed-off-by: Anton Lundin <glance@ac2.se>
> ---
>   .../bindings/hwmon/nuvoton,nct6775.yaml       |   1 +

One more comment: The above change needs to be a separate patch.

Guenter