Hi Doug,
On 3/27/2018 9:56 AM, Doug Anderson wrote: > Manu > > On Thu, Mar 22, 2018 at 11:11 PM, Manu Gautam <mgau...@codeaurora.org> wrote: >> QMP PHY for USB mode requires pipe_clk for calibration and PLL lock >> to take place. This clock is output from PHY to GCC clock_ctl and then >> fed back to QMP PHY and is available from PHY only after PHY is reset >> and initialized, hence it can't be enabled too early in initialization >> sequence. >> >> Signed-off-by: Manu Gautam <mgau...@codeaurora.org> >> --- >> drivers/phy/qualcomm/phy-qcom-qmp.c | 33 ++++++++++++++++++++++++++++++++- >> 1 file changed, 32 insertions(+), 1 deletion(-) > So it's now new with this patch, but it's more obvious with this > patch. It seems like "UFS/PCIE" is kinda broken w/ respect to how it > controls its clock. Specifically: > > * If you init the PHY but don't power it on, then you "exit" the PHY: > you'll disable/unprepare "pipe_clk" even though you never > prepare/enabled it. > > * If you init the PHY, power it on, power it off, power it on, and > exit the PHY: you'll leave the clock prepared one extra time. > > Specifically I'd expect: for UFS/PCIE the disable/unprepare should be > symmetric with the enable/prepare and should be in "power off", not in > exit. > > ...or did I miss something? > > > Interestingly, your patch fixes this problem for USB3 (where init/exit > are now symmetric), but leaves the problem there for UFS/PCIE. > Thanks for review. One of the reason why pipe_clk is disabled as part of phy_exit is that halt_check from clk_disable reports error if called after PHY has been powered down or phy_exit. I believe that warning should be ignored in qcom gcc-clock driver (for applicable platforms) by using BRANCH_HALT_DELAY as halt_check for pipe_clk and performing clk_disable from power_off for UFS/PCIE. I can implement that as separate patch once dependent gcc driver patch(es) gets in. Would that be ok? -Manu -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
