On Wed 08 Jun 14:22 CDT 2022, Bjorn Helgaas wrote: > On Wed, Jun 08, 2022 at 01:52:34PM +0300, Dmitry Baryshkov wrote: > > On recent Qualcomm platforms the QMP PIPE clocks feed into a set of > > muxes which must be parked to the "safe" source (bi_tcxo) when > > corresponding GDSC is turned off and on again. Currently this is > > handcoded in the PCIe driver by reparenting the gcc_pipe_N_clk_src > > clock. However the same code sequence should be applied in the > > pcie-qcom endpoint, USB3 and UFS drivers. > > > > Rather than copying this sequence over and over again, follow the > > example of clk_rcg2_shared_ops and implement this parking in the > > enable() and disable() clock operations. Supplement the regmap-mux with > > the new clk_regmap_phy_mux type, which implements such multiplexers > > as a simple gate clocks. > > > > This is possible since each of these multiplexers has just two clock > > sources: one coming from the PHY and a reference (XO) one. If the clock > > is running off the from-PHY source, report it as enabled. Report it as > > disabled otherwise (if it uses reference source). > > > > This way the PHY will disable the pipe clock before turning off the > > GDSC, which in turn would lead to disabling corresponding pipe_clk_src > > (and thus it being parked to a safe, reference clock source). And vice > > versa, after enabling the GDSC the PHY will enable the pipe clock, which > > would cause pipe_clk_src to be switched from a safe source to the > > working one. > > > > Reviewed-by: Johan Hovold <johan+linaro@xxxxxxxxxx> > > Tested-by: Johan Hovold <johan+linaro@xxxxxxxxxx> > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> > > --- > > drivers/clk/qcom/Makefile | 1 + > > drivers/clk/qcom/clk-regmap-phy-mux.c | 62 +++++++++++++++++++++++++++ > > drivers/clk/qcom/clk-regmap-phy-mux.h | 33 ++++++++++++++ > > 3 files changed, 96 insertions(+) > > create mode 100644 drivers/clk/qcom/clk-regmap-phy-mux.c > > create mode 100644 drivers/clk/qcom/clk-regmap-phy-mux.h > > Since it's posted as part of the series, I assume this should all be > applied together, so I'll look for an ack from Bjorn Andersson > <bjorn.andersson@xxxxxxxxxx>, maintainer of drivers/clk/qcom. Hi Bjorn, Picking the clock patch through the clock tree would allow us to fix up additional platforms (analog to patch 2 & 3) in time for v5.20 and reduces risk for merge conflicts. So please find an immutable branch (tag) of the clock patches here: https://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux.git tags/20220608105238.2973600-1-dmitry.baryshkov@xxxxxxxxxx Hope this suits you. Regards, Bjorn
