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authorOliver O'Halloran <oohall@gmail.com>2018-09-20 15:03:26 +1000
committerStewart Smith <stewart@linux.ibm.com>2018-09-27 00:41:48 -0500
commit30ffd4c6a528c7dc51ae0099db592dd442a314a4 (patch)
treedc930338d9278d24b3cc1fc1bd4deb6d022c8bef /hdata
parenta800fa35b8222996a634baeec27cd2369f7619f5 (diff)
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hdata: Explain what the xscom node bus-frequency is
Vague documentation is about as annoying as no documentation. Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Stewart Smith <stewart@linux.ibm.com>
Diffstat (limited to 'hdata')
-rw-r--r--hdata/spira.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/hdata/spira.c b/hdata/spira.c
index 2dd0dd3..5621870 100644
--- a/hdata/spira.c
+++ b/hdata/spira.c
@@ -281,7 +281,10 @@ static struct dt_node *add_xscom_node(uint64_t base, uint32_t hw_id,
}
dt_add_property_u64s(node, "reg", addr, size);
- /* Derive bus frquency */
+ /*
+ * The bus-frequency of the xscom node is actually the PIB/PCB
+ * frequency. It is derived from the nest-clock via a 4:1 divider
+ */
freq = dt_prop_get_u64_def(dt_root, "nest-frequency", 0);
freq /= 4;
if (freq)