libsensors: Add support for pwm

Add support for the pwm sensor interface.
This includes support for pwm[1-*], pwm[1-*]_enable,
pwm[1-*]_mode and pwm[1-*]_freq.

CHANGES

@@ -2,6 +2,7 @@ lm-sensors CHANGES file
 -----------------------
 
 git HEAD
+  Add PWM sensor support
 
 3.6.0 (2019-10-18)
   configs: Added a number of new configuration files

doc/libsensors-API.txt

@@ -6,6 +6,9 @@ over time. This document summarizes these evolutions so that application
 authors can quickly figure out how to test for the availability of a
 given new feature.
 
+0x501
+* Added support for pwm sensors
+
 0x500   lm-sensors 3.5.0
 * Added support for power min, lcrit, min_alarm and lcrit_alarm
   enum sensors_subfeature_type SENSORS_SUBFEATURE_POWER_MIN

lib/sensors.h

@@ -31,7 +31,7 @@
    when the API or ABI breaks), the third digit is incremented to track small
    API additions like new flags / enum values. The second digit is for tracking
    larger additions like new methods. */
-#define SENSORS_API_VERSION		0x500
+#define SENSORS_API_VERSION		0x501
 
 #define SENSORS_CHIP_NAME_PREFIX_ANY	NULL
 #define SENSORS_CHIP_NAME_ADDR_ANY	(-1)
@@ -143,6 +143,7 @@ typedef enum sensors_feature_type {
 	SENSORS_FEATURE_ENERGY		= 0x04,
 	SENSORS_FEATURE_CURR		= 0x05,
 	SENSORS_FEATURE_HUMIDITY	= 0x06,
+	SENSORS_FEATURE_PWM		= 0x07,
 	SENSORS_FEATURE_MAX_MAIN,
 	SENSORS_FEATURE_VID		= 0x10,
 	SENSORS_FEATURE_INTRUSION	= 0x11,
@@ -244,6 +245,11 @@ typedef enum sensors_subfeature_type {
 
 	SENSORS_SUBFEATURE_HUMIDITY_INPUT = SENSORS_FEATURE_HUMIDITY << 8,
 
+	SENSORS_SUBFEATURE_PWM_IO = SENSORS_FEATURE_PWM << 8,
+	SENSORS_SUBFEATURE_PWM_FREQ,
+	SENSORS_SUBFEATURE_PWM_ENABLE = (SENSORS_FEATURE_PWM << 8) | 0x80,
+	SENSORS_SUBFEATURE_PWM_MODE,
+
 	SENSORS_SUBFEATURE_VID = SENSORS_FEATURE_VID << 8,
 
 	SENSORS_SUBFEATURE_INTRUSION_ALARM = SENSORS_FEATURE_INTRUSION << 8,

lib/sysfs.c

@@ -149,6 +149,7 @@ int get_type_scaling(sensors_subfeature_type type)
 	case SENSORS_SUBFEATURE_HUMIDITY_INPUT:
 		return 1000;
 	case SENSORS_SUBFEATURE_FAN_INPUT:
+	case SENSORS_SUBFEATURE_PWM_IO:
 		return 1;
 	case SENSORS_SUBFEATURE_POWER_AVERAGE:
 	case SENSORS_SUBFEATURE_ENERGY_INPUT:
@@ -186,6 +187,13 @@ char *get_feature_name(sensors_feature_type ftype, char *sfname)
 		if (!name)
 			sensors_fatal_error(__func__, "Out of memory");
 
+		break;
+	case SENSORS_FEATURE_PWM:
+		/* Not all pwm subfeatures have a underscore in there name */
+		name = strndup(sfname, 4);
+		if (!name)
+			sensors_fatal_error(__func__, "Out of memory");
+
 		break;
 	default:
 		name = strdup(sfname);
@@ -319,6 +327,13 @@ static const struct subfeature_type_match humidity_matches[] = {
 	{ NULL, 0 }
 };
 
+static const struct subfeature_type_match pwm_matches[] = {
+	{ "enable", SENSORS_SUBFEATURE_PWM_ENABLE },
+	{ "mode", SENSORS_SUBFEATURE_PWM_MODE },
+	{ "freq", SENSORS_SUBFEATURE_PWM_FREQ },
+	{ NULL, 0 }
+};
+
 static const struct subfeature_type_match cpu_matches[] = {
 	{ "vid", SENSORS_SUBFEATURE_VID },
 	{ NULL, 0 }
@@ -339,6 +354,7 @@ static struct feature_type_match matches[] = {
 	{ "energy%d%c", energy_matches },
 	{ "intrusion%d%c", intrusion_matches },
 	{ "humidity%d%c", humidity_matches },
+	{ "pwm%d%c", pwm_matches },
 };
 
 /* Return the subfeature type and channel number based on the subfeature
@@ -356,9 +372,15 @@ sensors_subfeature_type sensors_subfeature_get_type(const char *name, int *nr)
 		return SENSORS_SUBFEATURE_BEEP_ENABLE;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(matches); i++)
-		if ((count = sscanf(name, matches[i].name, nr, &c)))
+	for (i = 0; i < ARRAY_SIZE(matches); i++) {
+		if ((count = sscanf(name, matches[i].name, nr, &c))) {
+			/* Needed for matching pwm[1-*] */
+			if (count == 1 && matches[i].submatches == pwm_matches)
+				return SENSORS_SUBFEATURE_PWM_IO;
+
 			break;
+		}
+	}
 
 	if (i == ARRAY_SIZE(matches) || count != 2 || c != '_')
 		return SENSORS_SUBFEATURE_UNKNOWN;  /* no match */
@@ -468,6 +490,7 @@ static int sensors_read_dynamic_chip(sensors_chip_features *chip,
 		case SENSORS_FEATURE_ENERGY:
 		case SENSORS_FEATURE_CURR:
 		case SENSORS_FEATURE_HUMIDITY:
+		case SENSORS_FEATURE_PWM:
 			nr--;
 			break;
 		default: