[v3,0/5] PCI: amlogic: Make PCIe working reliably on AXG platforms

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 appears to control band
gap reference.

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

While at it adding this PHY make AXG code close to G12A one 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 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 (5):
  phy: amlogic: Add Amlogic AXG PCIE PHY Driver
  PCI: amlogic: Use AXG PCIE PHY
  arm64: dts: meson-axg: Add PCIE PHY node
  dt-bindings: PCI: meson: Update PCIE bindings documentation
  dt-bindings: Add AXG PCIE PHY bindings

 .../bindings/pci/amlogic,meson-pcie.txt       |  22 +--
 .../bindings/phy/amlogic,meson-axg-pcie.yaml  |  51 +++++
 arch/arm64/boot/dts/amlogic/meson-axg.dtsi    |   9 +
 drivers/pci/controller/dwc/pci-meson.c        | 116 ++---------
 drivers/phy/amlogic/Kconfig                   |  11 ++
 drivers/phy/amlogic/Makefile                  |   1 +
 drivers/phy/amlogic/phy-meson-axg-pcie.c      | 185 ++++++++++++++++++
 7 files changed, 287 insertions(+), 108 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/phy/amlogic,meson-axg-pcie.yaml
 create mode 100644 drivers/phy/amlogic/phy-meson-axg-pcie.c

On Tue 24 Dec 2019 at 18:39, Remi Pommarel <repk@triplefau.lt> wrote:

> 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 appears to control band
> gap reference.
>
> As discussed here [1] one of these shared MIPI/PCIE PHY register bits was
> mistakenly implemented in the clock driver as CLKID_MIPI_ENABLE. This adds
> a PHY driver to control this bit through syscon subsystem instead, as well
> as setting the band gap one in order to get reliable PCIE communication.
>
> While at it adding this PHY make AXG code close to G12A one 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 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 (5):
>   phy: amlogic: Add Amlogic AXG PCIE PHY Driver
>   PCI: amlogic: Use AXG PCIE PHY
>   arm64: dts: meson-axg: Add PCIE PHY node
>   dt-bindings: PCI: meson: Update PCIE bindings documentation
>   dt-bindings: Add AXG PCIE PHY bindings

Hi Remi,

Usually, you should put the dt documentation first in the series.
This way the properties are documented before being used

>
>  .../bindings/pci/amlogic,meson-pcie.txt       |  22 +--
>  .../bindings/phy/amlogic,meson-axg-pcie.yaml  |  51 +++++
>  arch/arm64/boot/dts/amlogic/meson-axg.dtsi    |   9 +
>  drivers/pci/controller/dwc/pci-meson.c        | 116 ++---------
>  drivers/phy/amlogic/Kconfig                   |  11 ++
>  drivers/phy/amlogic/Makefile                  |   1 +
>  drivers/phy/amlogic/phy-meson-axg-pcie.c      | 185 ++++++++++++++++++
>  7 files changed, 287 insertions(+), 108 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/phy/amlogic,meson-axg-pcie.yaml
>  create mode 100644 drivers/phy/amlogic/phy-meson-axg-pcie.c