Re: [PATCH v5 0/4] tty/serial: meson_uart: add support for core clock handling

[Greg KH]

On Mon, Jun 19, 2017 at 10:43:05AM +0200, Neil Armstrong wrote:
> On 06/14/2017 10:29 AM, Neil Armstrong wrote:
> > This patchset is a re-spin of Helmut Klein's v3 patchset at [0] and the v4 patchset at [1].
> > 
> > Initially, the original patchset was made to enable usage on the non-AO UARTS
> > not enabled by the Bootloader (uart_B and uart_C), but the patchset needed
> > an overall change to have clean and stable DT bindings.
> > 
> > The Amlogic Meson UART Driver did not have stable DT bindings and mismatched
> > clock handling on non-AO UARTs since these "EE" UARTs needs a clock gate to
> > be ungated to works correctly.
> > In the same way, the AO UARTs does not need gating and can be used as
> > Early Consoles.
> > 
> > In the same time, the UART Interfaces can take clock input for the baudrate
> > generate from either the external Xtal or the internal Bus Clock (clk81).
> > 
> > So new bindings was necessary to meet these requirements and the DT
> > maintainers requirements.
> > 
> > The "legacy" binding actually used in the driver is left until all the DT
> > files are switched to the new bindings.
> > 
> > The GX DT has been tested, but the last 4 Meson6/Meson8/b are only
> > compile-tested, and testing is welcome.
> > Thus only the first 3 patches can be merged until the Meson6/Meson8/b are
> > formally tested.
> > 
> > It must be noted that the meson6 cannot work today except using an early
> > console since the UART driver could not probe without a clocks property.
> > 
> > Changes since v4 at [1]:
> >  - Droped meson8/meson8b DT patches
> >  - Fixes copy/paste error in patch 2
> >  - Refactored clock probing in patch 2
> >  - merged meson6 patches together to avoid breaking bisect
> > 
> > [0] http://lkml.kernel.org/r/20170331165437.26227-1-hgkr.klein@xxxxxxxxx
> > [1] http://lkml.kernel.org/r/1497001756-942-1-git-send-email-narmstrong@xxxxxxxxxxxx
> > 
> > Helmut Klein (3):
> >   dt-bindings: serial: Add bindings for the Amlogic Meson UARTs
> >   tty/serial: meson_uart: update to stable bindings
> >   ARM64: dts: meson-gx: use stable UART bindings with correct gate clock
> > 
> > Neil Armstrong (1):
> >   ARM: dts: meson6: use stable UART bindings
> > 
> >  .../bindings/serial/amlogic,meson-uart.txt         | 38 +++++++++
> >  arch/arm/boot/dts/meson.dtsi                       |  8 +-
> >  arch/arm/boot/dts/meson6.dtsi                      | 28 +++++++
> >  arch/arm64/boot/dts/amlogic/meson-gx.dtsi          | 12 ++-
> >  arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi        | 25 ++++++
> >  arch/arm64/boot/dts/amlogic/meson-gxl.dtsi         | 25 ++++++
> >  drivers/tty/serial/meson_uart.c                    | 90 ++++++++++++++++++++--
> >  7 files changed, 209 insertions(+), 17 deletions(-)
> >  create mode 100644 Documentation/devicetree/bindings/serial/amlogic,meson-uart.txt
> > 
> 
> 
> Hi Greg,
> 
> Patches 3 & 4 will need a respin to avoid breaking compatibility with old kernel
> like the tty patch does by keeping the legacy compatible string.
> I will re-send then in a separate thread and Kevin will handle them.
> 
> Patches 1 & 2 can be taken if they are OK for you.

Looks good, now applied, thanks.

Feel free to resend the other two whenever you have them ready.

greg k-h