[v6,0/2] phy: qcom: qmp-pcie: Add PCIe PHY no_csr reset support

Message

Wenbin Yao (Consultant) March 19, 2025, 9:45 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 v6:
- Return -ENODATA instead of -EINVAL when init sequence is not available.
- Link to v5: https://lore.kernel.org/all/[e-mail]/

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/[e-mail]/

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/[e-mail]/

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/[e-mail]/

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/[e-mail]/

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: b18ac9a805efdbc2e2720dded42b1ed26acadb24