[U-Boot] [PATCH v2 0/5] Add a pinctrl driver for Merrifield to pinmux I2C#6

[Bin Meng]

On Tue, Sep 4, 2018 at 10:34 PM Georgii Staroselskii
<georgii.staroselskii at emlid.com> wrote:
>
> We have lacked the support for any pinmuxing in U-Boot for Merrifield.
> A need for pinmuxing some pins has arisen from the fact the I2C#6 is shared
> with I2C#8 on Merrifield. The latter is not easily accessible because it's
> a part of a separate MCU we don't have easy access to.
>
> I2C#6 can be and should be made use of in Linux but couldn't because it
> was blocked by the SCU.
>
> The proposed change is to implement a minimalistic pinctrl driver that
> reads the configuration off a device tree blob and configures the pins
> accordingly.
>
> The driver needs some changes to SCU API and thus the addition of
> scu_ipc_raw_command().
>
> Andy Shevchenko has been helping me by making a prior review and made
> a lot of suggestions about the general approach that should be taken.
>
> He should also be given credit for the initial kernel code that I have
> taken as a reference.
>
> The code has been tested on 5 different Edisons on Intel Edison Breakout
> board and a couple of custom Emlid PCBs by booting a kernel and issuing
> a i2cdetect -r -y 6 and then loading a driver that made use of the bus.
>
> I also created a Gist on Github with a lot of relevant information like
>
> - output of `acpidump -o tables.dat`
> - dmesg
> - output of `grep -H 15 /sys/bus/acpi/devices/*/status`
> - cat /sys/kernel/debug/gpio
> - cat /sys/kernel/debug/pinctrl/INTC1002\:00/pins
> - output of `i2cdetect -y -r 6` w/ and w/o external device on the bus
>
> Here it is:
> https://gist.github.com/staroselskii/097808e05fd609dbafd4fe5ebd618708
>
> Changes in v2 (Sep 4, 2018)
> * fix most of the cosmetic issues
> * allow setting pinmodes other than 1
> * add a missing docstring to scu_ipc_command()
>

Somehow I did not receive all 5 patches in the v2. Only 2/3/5 is in my
inbox. It looks good and I will wait some comments from others (if
any) for another day or two before applying this.

>
> Georgii Staroselskii (5):
>   x86: cpu: introduce scu_ipc_raw_command()
>   x86: tangier: pinmux: add API to configure protected pins
>   x86: dts: edison: configure I2C#6 pins
>   x86: tangier: acpi: add I2C6 node
>   x86: cpu: add docstring to scu_ipc_command()
>
>  arch/x86/cpu/tangier/Makefile                      |   2 +-
>  arch/x86/cpu/tangier/pinmux.c                      | 196 +++++++++++++++++++++
>  arch/x86/dts/edison.dts                            |  22 +++
>  .../include/asm/arch-tangier/acpi/southcluster.asl |  10 ++
>  arch/x86/include/asm/scu.h                         |   4 +
>  arch/x86/lib/scu.c                                 |  62 +++++++
>  6 files changed, 295 insertions(+), 1 deletion(-)
>  create mode 100644 arch/x86/cpu/tangier/pinmux.c
>

Regards,
Bin