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[v7,0/2] phy: qcom: qmp-pcie: Add PCIe PHY no_csr reset support

Message ID 20250411113120.651363-1-quic_wenbyao@quicinc.com
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Series phy: qcom: qmp-pcie: Add PCIe PHY no_csr reset support | expand

Message

Wenbin Yao April 11, 2025, 11:31 a.m. UTC 
The series aims to skip phy register programming and drive PCIe PHY with
register setting programmed in bootloader by simply toggling no_csr reset,
which once togglled, PHY hardware will be reset while PHY registers are
retained.

First, determine whether PHY setting can be skipped by checking
QPHY_START_CTRL register and the existence of nocsr reset. If it is
programmed and no_csr reset is supported, do no_csr reset and skip BCR
reset which will reset entire PHY.

This series also remove has_nocsr_reset flag in qmp_phy_cfg structure and
decide whether the PHY supports nocsr reset by checking the existence of
nocsr reset in device tree.

The series are tested on X1E80100-QCP and HDK8550.

The commit messages of this patchset have been modified based on comments
and suggestions.

Changes in v7:
- Rebase on linux-phy/next branch.
- Link to v6: https://lore.kernel.org/all/20250319094544.3980357-1-quic_wenbyao@quicinc.com/

Changes in v6:
- Return -ENODATA instead of -EINVAL when init sequence is not available.
- Link to v5: https://lore.kernel.org/all/20250226103600.1923047-1-quic_wenbyao@quicinc.com/

Changes in v5:
- Add a check whether the init sequences are exist if the PHY needs to be
  initialized to Patch 2/2.
- Link to v4: https://lore.kernel.org/all/20250220102253.755116-1-quic_wenbyao@quicinc.com/

Changes in v4:
- Add Philipp's Reviewed-by tag to Patch 1/2.
- Use PHY instead of phy in comments in Patch 2/2.
- Use "if (qmp->nocsr_reset)" instead of "if (!qmp->nocsr_reset)" in
  function qmp_pcie_exit for readability in Patch 2/2.
- Use goto statements in function qmp_pcie_power_on and qmp_pcie_power_off
  for readability in Patch 2/2.
- Refine the comment of why not checking qmp->skip_init when reset PHY in
  function qmp_pcie_power_off in Patch 2/2.
- Link to v3: https://lore.kernel.org/all/20250214104539.281846-1-quic_wenbyao@quicinc.com/

Changes in v3:
- Replace devm_reset_control_get_exclusive with
  devm_reset_control_get_optional_exclusive when get phy_nocsr reset
  control in Patch 1/2.
- Do not ignore -EINVAL when get phy_nocsr reset control in Patch 1/2.
- Replace phy_initialized with skip_init in struct qmp_pcie in Patch 2/2.
- Add a comment to why not check qmp->skip_init in function
  qmp_pcie_power_off in Patch 2/2.
- Link to v2: https://lore.kernel.org/all/20250211094231.1813558-1-quic_wenbyao@quicinc.com/

Changes in v2:
- Add Abel's and Manivannan's Reviewed-by tag to Patch 1/2.
- Refine commit msg of Patch 2/2.
- Link to v1: https://lore.kernel.org/all/20250121094140.4006801-1-quic_wenbyao@quicinc.com/

Konrad Dybcio (1):
  phy: qcom: pcie: Determine has_nocsr_reset dynamically

Qiang Yu (1):
  phy: qcom: qmp-pcie: Add PHY register retention support

 drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 86 +++++++++++++++++-------
 1 file changed, 63 insertions(+), 23 deletions(-)


base-commit: 0af2f6be1b4281385b618cb86ad946eded089ac8