Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

1 files changed, 18 insertions, 2 deletions

diff --git a/Documentation/hwmon/lm77 b/Documentation/hwmon/lm77
index 57c3a46d637..bfc915fe363 100644
--- a/Documentation/hwmon/lm77
+++ b/Documentation/hwmon/lm77
@@ -18,5 +18,21 @@ sensor incorporates a band-gap type temperature sensor,
 10-bit ADC, and a digital comparator with user-programmable upper
 and lower limit values.
 
-Limits can be set through the Overtemperature Shutdown register and
-Hysteresis register.
+The LM77 implements 3 limits: low (temp1_min), high (temp1_max) and
+critical (temp1_crit.) It also implements an hysteresis mechanism which
+applies to all 3 limits. The relative difference is stored in a single
+register on the chip, which means that the relative difference between
+the limit and its hysteresis is always the same for all 3 limits.
+
+This implementation detail implies the following:
+* When setting a limit, its hysteresis will automatically follow, the
+  difference staying unchanged. For example, if the old critical limit
+  was 80 degrees C, and the hysteresis was 75 degrees C, and you change
+  the critical limit to 90 degrees C, then the hysteresis will
+  automatically change to 85 degrees C.
+* All 3 hysteresis can't be set independently. We decided to make
+  temp1_crit_hyst writable, while temp1_min_hyst and temp1_max_hyst are
+  read-only. Setting temp1_crit_hyst writes the difference between
+  temp1_crit_hyst and temp1_crit into the chip, and the same relative
+  hysteresis applies automatically to the low and high limits.
+* The limits should be set before the hysteresis.