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

[Tom Rini <trini@konsulko.com>]

On Wed, Jul 11, 2018 at 03:31:39PM +0200, Michal Simek wrote:
> On 11.7.2018 14:46, Tom Rini wrote:
> > On Wed, Jul 11, 2018 at 07:57:13AM +0200, Michal Simek wrote:
> >> On 10.7.2018 18:40, Tom Rini wrote:
> >>> 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@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@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@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@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@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.
> >>
> >> I would expect that almost everybody will enable CMD_DM where symbol is
> >> in cmd/Kconfig but implementation in test/dm/cmd_dm.c (it is a question
> >> if this is the right place for this file).
> > 
> > It might well really belong as cmd/dm.c, but content wise it's debug
> > information that is also useful in the bind/unbind case (so you know
> > where U-Boot sees things as being at).
> 
> Then we should really not enable it by default for all boards with DM on.
> 
>  640 config CMD_DM
>  641         bool "dm - Access to driver model information"
>  642         depends on DM
>  643         default y

Simon?

-- 
Tom
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