[Skiboot] [PATCH] doc/device-tree: Add descriptions for the ibm, pstate-* properties.

Jeremy Kerr jk at ozlabs.org
Tue Mar 17 16:49:31 AEDT 2015

Signed-off-by: Jeremy Kerr <jk at ozlabs.org>

 doc/device-tree/ibm,opal/power-mgt.txt |   40 ++++++++++++++++---------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/doc/device-tree/ibm,opal/power-mgt.txt b/doc/device-tree/ibm,opal/power-mgt.txt
index d67c1b3..0852650 100644
--- a/doc/device-tree/ibm,opal/power-mgt.txt
+++ b/doc/device-tree/ibm,opal/power-mgt.txt
@@ -25,18 +25,35 @@ values for optimal power efficiency.
 ibm,cpu-idle-state-residency-ns = <0x1 0x2 0x3>
 ibm,cpu-idle-state-latencies-ns = <0x1 0x2 0x3>
+This property lists the available pstate identifiers, as signed 32-bit
+big-endian values. While the identifiers are somewhat arbitrary, these define
+the order of the pstates in other ibm,pstate-* properties.
+This property lists the frequency, in MHz, of each of the pstates listed in the
+ibm,pstate-ids file. Each frequency is a 32-bit big-endian word.
+ibm,pstate-max ibm,pstate-min ibm,pstate-nominal
+These properties give the maximum, minimum and nominal pstate values, as an id
+specified in the ibm,pstate-ids file.
 ibm,pstate-vcss ibm,pstate-vdds
-During characterisation, we'd like to allow userspace to see the vdd and
-vcs values exposed by the OCC. This change adds two new properties to
-expose these:
- ibm,pstate-vdds
- ibm,pstate-vcss
-- containing one byte per pstate, representing the Vdd or Vcs value for
-  that pstate.
+These properties list a voltage-identifier of each of the pstates listed in
+ibm,pstate-ids for the Vcs and Vdd values used for that pstate. Each VID is a
+single byte.
 FIXME: document these:
@@ -44,8 +61,3 @@ ibm,cpu-idle-state-flags

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