On 03/11/2019 08:14 PM, Sergei Shtylyov wrote: [...] > No hangs were seen on V3M, despite the RPCD2 clock remained disabled. > The RPC clocks on both V3H and V3M suffer from a lack of clear documentation... > >> See also section 62.4.7 (Frequency change), which does not have a >> subsection for V3H, but it may be impacted (changing RPCD2 causes >> an additional read of RPCCKR, satisfying the read-after-write requirement >> documented there). > > Hmm, haven't seen this item before; it looks like we can't use the standard > divider component. BTW, this section in the 1.50 manual tells to use the soft > reset on V3MOK. OK, I'll investigate this... Now I have: the frequency change didn't seem to happen, and without RPCD2 enabled the CMNCR read still hangs, even when I added readl() call into clk_writel(). So I think my patch was correct. >>> Fixes: 94e3935b5756 ("clk: renesas: r8a77980: Add RPC clocks") >>> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> > [...] MBR, Sergei