[U-Boot] [PATCH v3 7/7] cmd: Add bind/unbind commands to bind a device to a driver from the command line

[Joe Hershberger]

On Mon, Jul 9, 2018 at 9:43 AM, Tom Rini <trini at konsulko.com> wrote:
> On Mon, Jul 09, 2018 at 08:19:44AM +0200, Michal Simek wrote:
>> On 30.6.2018 06:19, Simon Glass wrote:
>> > On 27 June 2018 at 07:13, Michal Simek <michal.simek at xilinx.com> wrote:
>> >> On 22.6.2018 14:25, Jean-Jacques Hiblot wrote:
>> >>> In some cases it can be useful to be able to bind a device to a driver from
>> >>> the command line.
>> >>> The obvious example is for versatile devices such as USB gadget.
>> >>> Another use case is when the devices are not yet ready at startup and
>> >>> require some setup before the drivers are bound (ex: FPGA which bitsream is
>> >>> fetched from a mass storage or ethernet)
>> >>>
>> >>> usage example:
>> >>>
>> >>> bind usb_dev_generic 0 usb_ether
>> >>> unbind usb_dev_generic 0 usb_ether
>> >>> or
>> >>> unbind eth 1
>> >>>
>> >>> bind /ocp/omap_dwc3 at 48380000/usb at 48390000 usb_ether
>> >>> unbind /ocp/omap_dwc3 at 48380000/usb at 48390000
>> >>>
>> >>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot at ti.com>
>> >>>
>> >>> ---
>> >>>
>> >>> Changes in v3:
>> >>> - factorize code based on comments from ML
>> >>> - remove the devices before unbinding them
>> >>> - use device_find_global_by_ofnode() to get a device by its node.
>> >>> - Added tests
>> >>>
>> >>> Changes in v2:
>> >>> - Make the bind/unbind command generic, not specific to usb device.
>> >>> - Update the API to be able to bind/unbind based on DTS node path
>> >>> - Add a Kconfig option to select the bind/unbind commands
>> >>>
>> >>>  arch/sandbox/dts/test.dts  |  11 ++
>> >>>  cmd/Kconfig                |   9 ++
>> >>>  cmd/Makefile               |   1 +
>> >>>  cmd/bind.c                 | 255 +++++++++++++++++++++++++++++++++++++++++++++
>> >>>  configs/sandbox_defconfig  |   1 +
>> >>>  test/py/tests/test_bind.py | 178 +++++++++++++++++++++++++++++++
>> >>>  6 files changed, 455 insertions(+)
>> >>>  create mode 100644 cmd/bind.c
>> >>>  create mode 100644 test/py/tests/test_bind.py
>> >
>> > Reviewed-by: Simon Glass <sjg at chromium.org>
>> >
>> > Nice work
>> >
>> > [...]
>> >
>> >>
>> >> I have tested bind/unbind with dwc3 on zynqmp for ethernet gadget and it
>> >> is working fine for me.
>> >> I have also tried to use bind/unbind for gpio zynqmp driver and it is
>> >> also working fine.
>> >>
>> >> It means
>> >> Tested-by: Michal Simek <michal.simek at xilinx.com>
>> >>
>> >> I would prefer if these commands are called as dm bind and dm unbind
>> >> instead of simply bind/unbind which should also fit to dm command
>> >> description "dm - Driver model low level access".
>> >
>> > Yes i can see the point. But after thinking about it, maybe it is best
>> > as it is? After all driver model is fundamental to U-Boot and it's not
>> > clear what else we might bind/unbind.
>> >
>> > I'd like to get other opinions here, too.
>>
>> Tom/Marek: Any opinion?
>
> I think dm bind/unbind makes sense, yes.  "bind" and "unbind" are pretty
> generic terms and making it clear it's part of working "inside" of DM to
> hook/unhook things by making it a sub-command of dm sounds good.
> Thanks!

I agree with Simon here. I think bind and unbind won't have any
plausible other meaning in U-Boot and DM is core to U-Boot
functionality in the new world. I think it would be OK to have "dm
bind" alias to "bind" if that's a point of confusion, but having it
top-level seems good to me.

-Joe

> --
> Tom
>
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