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

[Tom Rini]

On Mon, Jul 09, 2018 at 11:59:57AM -0500, Joe Hershberger wrote:
> 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.

They're still very generic words for something that's part of working
under the dm framework.  That said, looking at test/dm/cmd_dm.c and that
it's supposed to be only for test/debug type work, yes, OK, I'll change
my mind.

-- 
Tom
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