Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging: (26 commits)
  hwmon: (w83627ehf) Better fix for negative temperature values
  hwmon: (w83627ehf) Uninline is_word_sized
  hwmon: (lm75) Document why clones are not detected
  hwmon: (w83627ehf) Move fan pins check to a separate function
  hwmon: (w83627ehf) Skip reading unused voltage registers
  hwmon: (lm75) Add support for Analog Devices ADT75
  hwmon: (pmbus_core) Simplify sign extensions
  hwmon: (pmbus) Add support for Lineage Power DC-DC converters
  hwmon: (pmbus/ltc2978) Add support for LTC3880 to LTC2978 driver
  hwmon: (pmbus/ltc2978) Explicit driver for LTC2978
  hwmon: (pmbus) Add support for TEMP2 peak attributes
  hwmon: AD7314 driver (ported from IIO)
  hwmon: (pmbus) Add support for Intersil power management chips
  hwmon: (pmbus) Always call _pmbus_read_byte in core driver
  hwmon: (pmbus) Replace EINVAL return codes with more appropriate errors
  hwmon: (pmbus) Provide more documentation
  hwmon/f71882fg: Make the decision wether to register fan attr. per fan
  hwmon/f71882fg: Add a f71882fg_create_fan_sysfs_files helper function
  hwmon/f71882fg: Make all fan/pwm attr tables 2 dimensional
  hwmon: (exynos4_tmu) Remove IRQF_DISABLED
  ...

1 files changed, 26 insertions, 13 deletions

diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index ef902d5..90126a2 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -35,6 +35,7 @@
  */
 
 enum lm75_type {		/* keep sorted in alphabetical order */
+	adt75,
 	ds1775,
 	ds75,
 	lm75,
@@ -213,6 +214,7 @@ static int lm75_remove(struct i2c_client *client)
 }
 
 static const struct i2c_device_id lm75_ids[] = {
+	{ "adt75", adt75, },
 	{ "ds1775", ds1775, },
 	{ "ds75", ds75, },
 	{ "lm75", lm75, },
@@ -247,19 +249,30 @@ static int lm75_detect(struct i2c_client *new_client,
 				     I2C_FUNC_SMBUS_WORD_DATA))
 		return -ENODEV;
 
-	/* Now, we do the remaining detection. There is no identification-
-	   dedicated register so we have to rely on several tricks:
-	   unused bits, registers cycling over 8-address boundaries,
-	   addresses 0x04-0x07 returning the last read value.
-	   The cycling+unused addresses combination is not tested,
-	   since it would significantly slow the detection down and would
-	   hardly add any value.
-
-	   The National Semiconductor LM75A is different than earlier
-	   LM75s.  It has an ID byte of 0xaX (where X is the chip
-	   revision, with 1 being the only revision in existence) in
-	   register 7, and unused registers return 0xff rather than the
-	   last read value. */
+	/*
+	 * Now, we do the remaining detection. There is no identification-
+	 * dedicated register so we have to rely on several tricks:
+	 * unused bits, registers cycling over 8-address boundaries,
+	 * addresses 0x04-0x07 returning the last read value.
+	 * The cycling+unused addresses combination is not tested,
+	 * since it would significantly slow the detection down and would
+	 * hardly add any value.
+	 *
+	 * The National Semiconductor LM75A is different than earlier
+	 * LM75s.  It has an ID byte of 0xaX (where X is the chip
+	 * revision, with 1 being the only revision in existence) in
+	 * register 7, and unused registers return 0xff rather than the
+	 * last read value.
+	 *
+	 * Note that this function only detects the original National
+	 * Semiconductor LM75 and the LM75A. Clones from other vendors
+	 * aren't detected, on purpose, because they are typically never
+	 * found on PC hardware. They are found on embedded designs where
+	 * they can be instantiated explicitly so detection is not needed.
+	 * The absence of identification registers on all these clones
+	 * would make their exhaustive detection very difficult and weak,
+	 * and odds are that the driver would bind to unsupported devices.
+	 */
 
 	/* Unused bits */
 	conf = i2c_smbus_read_byte_data(new_client, 1);