[PATCH v8 0/8] PCI: imx6: refine codes and add compliance tests mode support

[Richard Zhu <hongxing.zhu@nxp.com>]

This series patches refine pci-imx6 driver and do the following changes.
- Encapsulate the clock enable into one standalone function
- Add the error propagation from host_init
- Disable the regulators and clocks when link never comes up
- Add the compliance tests mode support

Main changes from v7 to v8:
Regarding Bjorn's review comments.
- Align the format of the dev_info message and refine commit log of
  #6/7/8 patches.
- Rename the err_reset_phy label, since there is no PHY reset in the out.

Main changes from v6 to v7:
- Keep the regulator usage counter balance in the #5 patch of v6 series.

Main changes from v5 to v6:
- Refer to the following discussion with Fabio, fix the dump by his patch.
  https://patchwork.kernel.org/project/linux-pci/patch/1641368602-20401-6-git-send-email-hongxing.zhu@nxp.com/
  Refine and rebase this patch-set after Fabio' dump fix patch is merged.
- Add one new #4 patch to disable i.MX6QDL REF clock too when disable clocks
- Split the regulator refine codes into one standalone patch #5 in this version.

Main changes from v4 to v5:
- Since i.MX8MM PCIe support had been merged. Based on Lorenzo's git repos,
  resend the patch-set after rebase.

Main changes from v3 to v4:
- Regarding Mark's comments, delete the regulator_is_enabled() check.
- Squash #3 and #6 of v3 patch into #5 patch of v4 set.

Main changes from v2 to v3:
- Add "Reviewed-by: Lucas Stach <l.stach@pengutronix.de>" tag into
  first two patches.
- Add a Fixes tag into #3 patch.
- Split the #4 of v2 to two patches, one is clock disable codes move,
  the other one is the acutal clock unbalance fix.
- Add a new host_exit() callback into dw_pcie_host_ops, then it could be
  invoked to handle the unbalance issue in the error handling after
  host_init() function when link is down.
- Add a new host_exit() callback for i.MX PCIe driver to handle this case
  in the error handling after host_init.

Main changes from v1 to v2:
Regarding Lucas' comments.
  - Move the placement of the new imx6_pcie_clk_enable() to avoid the
    forward declarition.
  - Seperate the second patch of v1 patch-set to three patches.
  - Use the module_param to replace the kernel command line.
Regarding Bjorn's comments:
  - Use the cover-letter for a multi-patch series.
  - Correct the subject line, and refine the commit logs. For example,
    remove the timestamp of the logs.

drivers/pci/controller/dwc/pci-imx6.c             | 223 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------------------------------
drivers/pci/controller/dwc/pcie-designware-host.c |   5 ++-
drivers/pci/controller/dwc/pcie-designware.h      |   1 +
3 files changed, 150 insertions(+), 79 deletions(-)

[PATCH v8 1/8] PCI: imx6: Encapsulate the clock enable into one
[PATCH v8 2/8] PCI: imx6: Add the error propagation from host_init
[PATCH v8 3/8] PCI: imx6: Move imx6_pcie_clk_disable() earlier
[PATCH v8 4/8] PCI: imx6: Disable iMX6QDL PCIe REF clock when disable
[PATCH v8 5/8] PCI: imx6: Refine the regulator usage
[PATCH v8 6/8] PCI: dwc: Add dw_pcie_host_ops.host_exit() callback
[PATCH v8 7/8] PCI: imx6: Disable clocks and regulators after link is
[PATCH v8 8/8] PCI: imx6: Add compliance tests mode support