On Tue 22 Jan 16:40 PST 2019, Doug Anderson wrote: > Hi, > > On Tue, Jan 22, 2019 at 4:26 PM Bjorn Andersson > <bjorn.andersson@xxxxxxxxxx> wrote: > > > > + clocks = <&xo_board>; > > > > + clock-names = "xo"; > > > > > > I've found that nearly all the places that refer to xo_board are wrong > > > and should actually point to '<&rpmhcc RPMH_CXO_CLK>'. Maybe yours > > > should too? > > > > > > > Yes, xo_board is a fake clock representing the 19.2MHz clock feeding the > > cxo (or cxo2) pad of the SoC. So you're definitely right in that this > > should be referencing the actual 19.2MHz clock. > > > > We've kept referring to this as xo_board, as we don't handle probe > > deferral when gcc will probe earlier than rpmcc in the boot and for > > other non-clock drivers the fear of actually hitting 0 on the refcounter > > for this (you don't want to disable the cxo while running the system). > > Note that, as defined in the device tree, "xo_board" is actually 38.4. > IIUC that is not actually a fake/bogus clock but represents the actual > crystal on the board. There's a divide by 2 in the CPU though so most > peripherals consider "xo" as 19.2. > There's the 38.4MHz XO connected to the PMIC, but the signal going into the CXO_IN pad of the SoC is supposed to come from LNBBCLK1 and be 19.2MHz. > ...OK, confirmed. The actual RF_XO_CLK pin on the board is truly > connected to 38.4. > And the three RF clocks from the PMIC are all ticking at 38.4MHz. The "xo" I need here is the LNBBCLK1 (RPMH_CXO_CLK in clk-rpmh), for the purpose of preventing the root clock to be turned off if apps goes to suspend while the modem is booting, before it has had a chance to tell RPM(h) that it needs it to be on. Regards, Bjorn
