hwmon: Add unspecified temperature thresholds to sysfs ABI

Some recent temperature sensor chips provide thresholds which are not associated
with lower or upper limits. The use of those thresholds is application specific.

Provide sysfs ABI attributes to support such thresholds.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
hwmon: (coretemp) Add support for thermal threshold attributes

Add support for T0 and T1 temperature thresholds using the new sysfs ABI
attributes tempX_thresholdY and tempX_thresholdY_triggered.

This patch is based on commit c814a4c7c4aad795835583344353963a0a673eb0, which
was reverted. For details on the threshold registers, see IA Manual vol 3A,
which can be downloaded from here:
        http://download.intel.com/design/processor/manuals/253668.pdf

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Durgadoss R <durgadoss.r@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
hwmon: Add notification and uevent support to sysfs ABI

Some hwmon drivers start adding support for alarm attribute notifications and
generate uevents. Standardize the ABI to be used for this purpose.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: R Durgadoss <durgadoss.r@intel.com>
hwmon: (smsc47b397) Fix compiler warning

Some configurations produce the following compiler warning:

drivers/hwmon/smsc47b397.c: In function 'smsc47b397_init':
drivers/hwmon/smsc47b397.c:385: warning: 'address' may be used uninitialized in this function

While this is a false positive, it can easily be fixed by overloading the return
value from smsc47b397_find with both address and error return code (the address
is an unsigned short and thus never negative). This also reduces module size by
a few bytes (64 bytes for x86_64).

Cc: Mark M. Hoffman <mhoffman@lightlink.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
hwmon: (smsc47m1) Fix compiler warning

Some configurations produce the following compiler warning:

drivers/hwmon/smsc47m1.c: In function 'sm_smsc47m1_init':
drivers/hwmon/smsc47m1.c:938: warning: 'address' may be used uninitialized in this function

While this is a false positive, it can easily be fixed by overloading the return
value from smsc47m1_find with both address and error return code (the address
is an unsigned short and thus never negative). This also reduces module size by
a few bytes (46 bytes for x86_64).

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
hwmon: (acpi_power_meter) Fix compiler warning seen in some configurations

In some configurations, BUG() does not result in an endless loop but returns
to the caller. This results in the following compiler warning:

drivers/hwmon/acpi_power_meter.c: In function 'show_str':
drivers/hwmon/acpi_power_meter.c:380: warning: 'val' may be used uninitialized in this function

Fix the warning by setting val to an empty string after BUG().

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
hwmon: (pmbus_core) Fix compiler warning

Some configurations produce the following compiler warning:

drivers/hwmon/pmbus/pmbus_core.c: In function 'pmbus_show_boolean':
drivers/hwmon/pmbus/pmbus_core.c:752: warning: 'val' may be used uninitialized in this function

While this is a false positive, it can easily be fixed by overloading the return
value from pmbus_get_boolean with both val and error return code (val is a
boolean and thus never negative).

Signed-off-by: Guenter Roeck <linux@roeck-us.net>