Add support for virtual hwmon devices. This closes Red Hat bug #437637

and ticket #2305.


git-svn-id: http://lm-sensors.org/svn/lm-sensors/branches/lm-sensors-3.0.0@5176 7894878c-1315-0410-8ee3-d5d059ff63e0

CHANGES

@@ -5,6 +5,7 @@ SVN-HEAD
   libsensors: Use __func__ instead of __FUNCTION__
               Parse the configuration file in C locale
               Late compute statements override early ones
+              Support virtual hwmon devices (#2309)
   sensors-detect: Add SMSC SCH5027D detection
                   Do not access I/O ports on PPC
                   Move south bridge sensor detection to the right section

doc/libsensors-API.txt

@@ -0,0 +1,14 @@
+libsensors API history
+======================
+
+SENSORS_API_VERSION tracks the evolutions made to the libsensors API
+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.
+
+0x401	lm-sensors SVN
+* Added bus type "virtual":
+  #define SENSORS_BUS_TYPE_VIRTUAL	4
+
+0x400	lm-sensors 3.0.0 to 3.0.1
+* Initial API.

lib/access.c

@@ -347,6 +347,8 @@ const char *sensors_get_adapter_name(const sensors_bus_id *bus)
 	   so we don't have any custom string to return. */
 	case SENSORS_BUS_TYPE_SPI:
 		return "SPI adapter";
+	case SENSORS_BUS_TYPE_VIRTUAL:
+		return "Virtual device";
 	}
 
 	/* bus types with several instances */

lib/data.c

@@ -109,6 +109,8 @@ int sensors_parse_chip_name(const char *name, sensors_chip_name *res)
 		res->bus.type = SENSORS_BUS_TYPE_PCI;
 	else if (!strncmp(name, "spi", dash - name))
 		res->bus.type = SENSORS_BUS_TYPE_SPI;
+	else if (!strncmp(name, "virtual", dash - name))
+		res->bus.type = SENSORS_BUS_TYPE_VIRTUAL;
 	else
 		goto ERROR;
 	name = dash + 1;
@@ -169,6 +171,9 @@ int sensors_snprintf_chip_name(char *str, size_t size,
 	case SENSORS_BUS_TYPE_SPI:
 		return snprintf(str, size, "%s-spi-%hd-%x", chip->prefix,
 				chip->bus.nr, chip->addr);
+	case SENSORS_BUS_TYPE_VIRTUAL:
+		return snprintf(str, size, "%s-virtual-%x", chip->prefix,
+				chip->addr);
 	}
 
 	return -SENSORS_ERR_CHIP_NAME;

lib/sensors.h

@@ -31,7 +31,7 @@
    when the API + 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 0x400
+#define SENSORS_API_VERSION 0x401
 
 #define SENSORS_CHIP_NAME_PREFIX_ANY NULL
 #define SENSORS_CHIP_NAME_ADDR_ANY -1
@@ -41,6 +41,7 @@
 #define SENSORS_BUS_TYPE_ISA	1
 #define SENSORS_BUS_TYPE_PCI	2
 #define SENSORS_BUS_TYPE_SPI	3
+#define SENSORS_BUS_TYPE_VIRTUAL	4
 #define SENSORS_BUS_NR_ANY	(-1)
 #define SENSORS_BUS_NR_IGNORE	(-2)
 

lib/sysfs.c

@@ -476,6 +476,15 @@ static int sensors_read_one_sysfs_chip(const char *dev_path,
 	if (!entry.chip.path)
 		sensors_fatal_error(__func__, "Out of memory");
 
+	if (dev_path == NULL) {
+		/* Virtual device */
+		entry.chip.bus.type = SENSORS_BUS_TYPE_VIRTUAL;
+		entry.chip.bus.nr = 0;
+		/* For now we assume that virtual devices are unique */
+		entry.chip.addr = 0;
+		goto done;
+	}
+
 	/* Find bus type */
 	snprintf(linkpath, NAME_MAX, "%s/subsystem", dev_path);
 	sub_len = readlink(linkpath, subsys_path, NAME_MAX - 1);
@@ -545,6 +554,7 @@ static int sensors_read_one_sysfs_chip(const char *dev_path,
 		goto exit_free;
 	}
 
+done:
 	if (sensors_read_dynamic_chip(&entry, hwmon_path) < 0)
 		goto exit_free;
 	if (!entry.subfeature) { /* No subfeature, discard chip */
@@ -593,16 +603,20 @@ static int sensors_add_hwmon_device(const char *path, const char *classdev)
 
 	snprintf(linkpath, NAME_MAX, "%s/device", path);
 	dev_len = readlink(linkpath, device, NAME_MAX - 1);
-	if (dev_len < 0)
-		return -SENSORS_ERR_KERNEL;
-	device[dev_len] = '\0';
-	device_p = strrchr(device, '/') + 1;
+	if (dev_len < 0) {
+		/* No device link? Treat as virtual */
+		err = sensors_read_one_sysfs_chip(NULL, NULL, path);
+	} else {
+		device[dev_len] = '\0';
+		device_p = strrchr(device, '/') + 1;
 
-	/* The attributes we want might be those of the hwmon class device,
-	   or those of the device itself. */
-	err = sensors_read_one_sysfs_chip(linkpath, device_p, path);
-	if (err == 0)
-		err = sensors_read_one_sysfs_chip(linkpath, device_p, linkpath);
+		/* The attributes we want might be those of the hwmon class
+		   device, or those of the device itself. */
+		err = sensors_read_one_sysfs_chip(linkpath, device_p, path);
+		if (err == 0)
+			err = sensors_read_one_sysfs_chip(linkpath, device_p,
+							  linkpath);
+	}
 	if (err < 0)
 		return err;
 	return 0;