[v4,0/7] PCI: amlogic: Make PCIe working reliably on AXG platforms

Message

Remi Pommarel Jan. 15, 2020, 12:29 p.m. UTC

PCIe device probing failures have been seen on AXG platforms and were due
to unreliable clock signal output. Setting HHI_MIPI_CNTL0[26] bit in
MIPI's PHY registers solved the problem. This bit controls band gap
reference.

As discussed here [1] one of these shared MIPI/PCIE PHY register bits was
implemented in the clock driver as CLKID_MIPI_ENABLE. This adds a PHY
driver to control this bit instead, as well as setting the band gap one
in order to get reliable PCIE communication.

While at it add another PHY driver to control PCIE only PHY registers,
making AXG code more similar to G12A platform thus allowing to remove
some specific platform handling in pci-meson driver.

Please note that CLKID_MIPI_ENABLE removable will be done in a different
serie.

Changes since v3:
 - Go back to the shared MIPI/PCIe phy driver solution from v2
 - Remove syscon usage
 - Add all dt-bindings documentation

Changes since v2:
 - Remove shared MIPI/PCIE device driver and use syscon to access register
   in PCIE only driver instead
 - Include devicetree documentation

Changes sinve v1:
 - Move HHI_MIPI_CNTL0 bit control in its own PHY driver
 - Add a PHY driver for PCIE_PHY registers
 - Modify pci-meson.c to make use of both PHYs and remove specific
   handling for AXG and G12A

[1] https://lkml.org/lkml/2019/12/16/119

Remi Pommarel (7):
  dt-bindings: Add AXG PCIE PHY bindings
  dt-bindings: Add AXG shared MIPI/PCIE PHY bindings
  dt-bindings: PCI: meson: Update PCIE bindings documentation
  arm64: dts: meson-axg: Add PCIE PHY nodes
  phy: amlogic: Add Amlogic AXG MIPI/PCIE PHY Driver
  phy: amlogic: Add Amlogic AXG PCIE PHY Driver
  PCI: amlogic: Use AXG PCIE and shared MIPI/PCIE PHYs

 .../bindings/pci/amlogic,meson-pcie.txt       |  22 +--
 .../phy/amlogic,meson-axg-mipi-pcie.yaml      |  34 ++++
 .../bindings/phy/amlogic,meson-axg-pcie.yaml  |  40 ++++
 arch/arm64/boot/dts/amlogic/meson-axg.dtsi    |  13 ++
 drivers/pci/controller/dwc/pci-meson.c        | 140 +++++---------
 drivers/phy/amlogic/Kconfig                   |  22 +++
 drivers/phy/amlogic/Makefile                  |   2 +
 drivers/phy/amlogic/phy-meson-axg-mipi-pcie.c | 179 ++++++++++++++++++
 drivers/phy/amlogic/phy-meson-axg-pcie.c      | 163 ++++++++++++++++
 9 files changed, 508 insertions(+), 107 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/phy/amlogic,meson-axg-mipi-pcie.yaml
 create mode 100644 Documentation/devicetree/bindings/phy/amlogic,meson-axg-pcie.yaml
 create mode 100644 drivers/phy/amlogic/phy-meson-axg-mipi-pcie.c
 create mode 100644 drivers/phy/amlogic/phy-meson-axg-pcie.c