[v9,0/5] PCI: qcom: Rework pipe_clk/pipe_clk_src handling

Message

Dmitry Baryshkov June 3, 2022, 7:59 a.m. UTC

PCIe pipe clk (and some other clocks) 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.

Instead of doing it manually, follow the approach used by
clk_rcg2_shared_ops and implement this parking in the enable() and
disable() clock operations for respective pipe clocks.

Changes since v8:
 - Readded .name to changed entries in gcc-sc7280 driver to restore
   compatibility with older DTS,
 - Rebased on top of linux-next, dropping reverts,
 - Verified to include all R-b tags (excuse me, Johan, I missed them
   in the previous iteration).

Changes since v7:
 - Brought back the struct clk_regmap_phy_mux (Johan)
 - Fixed includes (Stephen)
 - Dropped CLK_SET_RATE_PARENT flags from changed pipe clocks, they are
   not set in the current code and they are useless as the PHY's clock
   has fixed rate.

Changes since v6:
 - Switched the ops to use GENMASK/FIELD_GET/FIELD_PUT (Stephen),
 - As all pipe/symbol clock source clocks have the same register (and
   parents) layout, hardcode all the values. If the need arises, this
   can be changed later (Stephen),
 - Fixed commit messages and comments (suggested by Johan),
 - Added revert for the clk_regmap_mux_safe that have been already
   picked up by Bjorn.

Changes since v5:
 - Rename the clock to clk-regmap-phy-mux and the enable/disable values
   to phy_src_val and ref_src_val respectively (as recommended by
   Johan).

Changes since v4:
 - Renamed the clock to clk-regmap-pipe-src,
 - Added mention of PCIe2 PHY to the commit message,
 - Expanded commit messages to mention additional pipe clock details.

Changes since v3:
 - Replaced the clock multiplexer implementation with branch-like clock.

Changes since v2:
 - Added is_enabled() callback
 - Added default parent to the pipe clock configuration

Changes since v1:
 - Rebased on top of [1].
 - Removed erroneous Fixes tag from the patch 4.

Changes since RFC:
 - Rework clk-regmap-mux fields. Specify safe parent as P_* value rather
   than specifying the register value directly
 - Expand commit message to the first patch to specially mention that
   it is required only on newer generations of Qualcomm chipsets.

Dmitry Baryshkov (5):
  clk: qcom: regmap: add PHY clock source implementation
  clk: qcom: gcc-sm8450: use new clk_regmap_phy_mux_ops for PCIe pipe
    clocks
  clk: qcom: gcc-sc7280: use new clk_regmap_phy_mux_ops for PCIe pipe
    clocks
  PCI: qcom: Remove unnecessary pipe_clk handling
  PCI: qcom: Drop manual pipe_clk_src handling

 drivers/clk/qcom/Makefile              |  1 +
 drivers/clk/qcom/clk-regmap-phy-mux.c  | 62 ++++++++++++++++++++
 drivers/clk/qcom/clk-regmap-phy-mux.h  | 33 +++++++++++
 drivers/clk/qcom/gcc-sc7280.c          | 47 +++++----------
 drivers/clk/qcom/gcc-sm8450.c          | 49 +++++-----------
 drivers/pci/controller/dwc/pcie-qcom.c | 81 +-------------------------
 6 files changed, 125 insertions(+), 148 deletions(-)
 create mode 100644 drivers/clk/qcom/clk-regmap-phy-mux.c
 create mode 100644 drivers/clk/qcom/clk-regmap-phy-mux.h