From 30ffd4c6a528c7dc51ae0099db592dd442a314a4 Mon Sep 17 00:00:00 2001 From: Oliver O'Halloran Date: Thu, 20 Sep 2018 15:03:26 +1000 Subject: hdata: Explain what the xscom node bus-frequency is Vague documentation is about as annoying as no documentation. Signed-off-by: Oliver O'Halloran Signed-off-by: Stewart Smith --- hdata/spira.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'hdata') diff --git a/hdata/spira.c b/hdata/spira.c index 2dd0dd36..56218709 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) -- cgit v1.2.1