On Thu, Feb 01, 2024 at 04:55:23PM +0100, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <[email protected]>
>
> I'd like to preface the cover letter by saying right away that this
> series is not complete. It's an RFC that presents my approach and is sent
> to the list for discussion. There are no DT bindings nor docs in
> Documentation/ yet. Please review it as an RFC and not an upstreambound
> series. If the approach is accepted as correct, I'll add missing bits.
>
> The RFC[1] presenting my proposed device-tree representation of the
> QCA6391 package present on the RB5 board - while not really officially
> accepted - was not outright rejected which is a good sign.
>
> This series incorporates it and builds a proposed power sequencing
> subsystem together with the first dedicated driver around it. Then it
> adds first two users: the Bluetooth and WLAN modules of the QCA6391.
>
> The Bluetooth part is pretty straightforward. The WLAN however is a PCIe
> device and as such needs to be powered-up *before* it's detected on the
> PCI bus. To that end, we modify the PCI core to instantiate platform
> devices for existing DT child nodes of the PCIe ports. For those nodes
> for which a power-sequencing driver exists, we bind it and let it probe.
> The driver then triggers a rescan of the PCI bus with the aim of
> detecting the now powered-on device. The device will consume the same DT
> node as the platform, power-sequencing device. We use device links to
> make the latter become the parent of the former.
>
> The main advantage of the above approach (both for PCI as well as
> generic power sequencers) is that we don't introduce significant changes
> in DT bindings and don't introduce new properties. We merely define new
> resources.
>
> [1] https://lore.kernel.org/all/CAMRc=MckG32DQv7b1AQL-mbnYdx4fsdYWtLwCyXc5Ma7EeSAKw@mail.gmail.com/T/#md5dc62007d12f6833d4e51658b14e0493954ba68
FWIW, booting RB5 with this patch series does give me working working
WiFI. But I do see the following splat during boot:
[ 5.880411] sysfs: cannot create duplicate filename '/devices/platform/soc@0/1c00000.pcie/pci0000:00/0000:00:00.0/resource0'
[ 5.891938] CPU: 5 PID: 68 Comm: kworker/u16:4 Not tainted 6.8.0-rc2-next-20240131-00009-g079fdad54c8f #199
[ 5.901927] Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT)
[ 5.908808] Workqueue: events_unbound async_run_entry_fn
[ 5.914274] Call trace:
[ 5.916794] dump_backtrace+0xec/0x108
[ 5.920649] show_stack+0x18/0x24
[ 5.924062] dump_stack_lvl+0x50/0x68
[ 5.927826] dump_stack+0x18/0x24
[ 5.931238] sysfs_warn_dup+0x64/0x80
[ 5.935004] sysfs_create_bin_file+0xf4/0x130
[ 5.939480] pci_create_attr+0x100/0x168
[ 5.943509] pci_create_sysfs_dev_files+0x6c/0xc0
[ 5.948337] pci_bus_add_device+0x60/0x114
[ 5.952551] pci_bus_add_devices+0x4c/0x7c
[ 5.956762] pci_host_probe+0x138/0x188
[ 5.960700] dw_pcie_host_init+0x290/0x334
[ 5.964914] qcom_pcie_probe+0x1f8/0x23c
[ 5.968942] platform_probe+0xa8/0xd0
[ 5.972707] really_probe+0x130/0x2e4
[ 5.976469] __driver_probe_device+0xa0/0x128
[ 5.980944] driver_probe_device+0x3c/0x1f8
[ 5.985245] __device_attach_driver+0x118/0x140
[ 5.989897] bus_for_each_drv+0xf4/0x14c
[ 5.993923] __device_attach_async_helper+0x78/0xd0
[ 5.998937] async_run_entry_fn+0x24/0xdc
[ 6.003051] process_scheduled_works+0x210/0x328
[ 6.007793] worker_thread+0x28c/0x450
[ 6.011642] kthread+0xfc/0x184
[ 6.014865] ret_from_fork+0x10/0x20
[ 6.018572] ------------[ cut here ]------------
[ 6.023339] proc_dir_entry '0000:00/00.0' already registered
Regards,
Bjorn