[PATCH 6.6.y] stm32mp15: WARNING after poweroff command

[Christoph Niedermaier <cniedermaier@dh-electronics.com>]

Hi stable team,

I would suggest to apply the patch
470a66268856 ("i2c: stm32f7: Add atomic_xfer method to driver")
from 6.7-rc1 to the stable Kernel 6.6.y.

Here is why:
After the commit
6e9df38f359a ("mfd: stpmic1: Add PMIC poweroff via sys-off handler")
from 6.5-rc1 the following WARNING appears after calling the poweroff
command:

[  791.813369] systemd-shutdown[1]: Syncing filesystems and block devices.
[  792.865580] systemd-shutdown[1]: Sending SIGTERM to remaining processes...
[  792.921103] systemd-journald[101]: Received SIGTERM from PID 1 (systemd-shutdow).
[  792.936515] systemd-shutdown[1]: Sending SIGKILL to remaining processes...
[  792.968715] systemd-shutdown[1]: Unmounting file systems.
[  792.979332] (sd-remount)[315]: Remounting '/' read-only with options ''.
[  793.219266] EXT4-fs (mmcblk2p4): re-mounted f7da42a1-2eed-4d39-a31e-e0ffadb97b28 ro. Quota mode: disabled.
[  793.238398] systemd-shutdown[1]: All filesystems unmounted.
[  793.242736] systemd-shutdown[1]: Deactivating swaps.
[  793.248004] systemd-shutdown[1]: All swaps deactivated.
[  793.252937] systemd-shutdown[1]: Detaching loop devices.
[  793.272548] systemd-shutdown[1]: All loop devices detached.
[  793.276918] systemd-shutdown[1]: Stopping MD devices.
[  793.282790] systemd-shutdown[1]: All MD devices stopped.
[  793.287128] systemd-shutdown[1]: Detaching DM devices.
[  793.292995] systemd-shutdown[1]: All DM devices detached.
[  793.297731] systemd-shutdown[1]: All filesystems, swaps, loop devices, MD devices and DM devices detached.
[  793.320636] systemd-shutdown[1]: Syncing filesystems and block devices.
[  793.326078] systemd-shutdown[1]: Powering off.
[  793.348421] reboot: Power down
[  793.350129] ------------[ cut here ]------------
[  793.354691] WARNING: CPU: 0 PID: 1 at drivers/i2c/i2c-core.h:42 i2c_transfer+0x5d/0x7c
[  793.362617] No atomic I2C transfer handler for 'i2c-2'
[  793.367780] Modules linked in:
[  793.370838] CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 6.6.41-lardisbox2-00053-g41e0b7f0166f #12
[  793.380047] Hardware name: STM32 (Device Tree Support)
[  793.385122]  unwind_backtrace from show_stack+0xb/0xc
[  793.390215]  show_stack from dump_stack_lvl+0x2b/0x34
[  793.395202]  dump_stack_lvl from __warn+0x5d/0xc4
[  793.399993]  __warn from warn_slowpath_fmt+0x55/0xa8
[  793.404887]  warn_slowpath_fmt from i2c_transfer+0x5d/0x7c
[  793.410387]  i2c_transfer from regmap_i2c_read+0x41/0x6c
[  793.415681]  regmap_i2c_read from _regmap_raw_read+0x87/0xe8
[  793.421378]  _regmap_raw_read from _regmap_bus_read+0x21/0x38
[  793.427079]  _regmap_bus_read from _regmap_read+0x55/0x9c
[  793.432477]  _regmap_read from _regmap_update_bits+0x71/0xa4
[  793.438175]  _regmap_update_bits from regmap_update_bits_base+0x2f/0x42
[  793.444784]  regmap_update_bits_base from stpmic1_power_off+0x19/0x20
[  793.451188]  stpmic1_power_off from sys_off_notify+0x1b/0x38
[  793.456880]  sys_off_notify from notifier_call_chain+0x57/0x78
[  793.462668]  notifier_call_chain from atomic_notifier_call_chain+0x11/0x16
[  793.469562]  atomic_notifier_call_chain from do_kernel_power_off+0x21/0x38
[  793.476461]  do_kernel_power_off from __do_sys_reboot+0xdf/0x150
[  793.482456]  __do_sys_reboot from ret_fast_syscall+0x1/0x5c
[  793.488042] Exception stack(0xf0815fa8 to 0xf0815ff0)
[  793.493017] 5fa0:                   00000000 00000000 fee1dead 28121969 4321fedc 00000000
[  793.501218] 5fc0: 00000000 00000000 00000000 00000058 0001884c 00000003 00000000 00018140
[  793.509414] 5fe0: 00000058 bee18c34 b6c20cdd b6b995a6
[  793.514478] ---[ end trace 000000000000000

This can be eliminated by backporting the above mentioned patch. I tested
it with a DHCOM stm32mp157c on a PDK2 board.

Thanks and regards
Christoph