[BUG] sun4i: axp209: no atomic i2c transfer handler

[Priit Laes]

Heya!

I have seen following warning message for few times when shutting down the
machine (Olinuxino Lime2-emmc) running the mainline kernel.

[snip]
WARNING: CPU: 0 PID: 1 at drivers/i2c/i2c-core.h:41 i2c_transfer+0xe8/0xf4
No atomic I2C transfer handler for 'i2c-1'
Modules linked in: enc28j60
CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 5.3.0-rc8-paf+ #28
Hardware name: Allwinner sun7i (A20) Family
[<c010ee08>] (unwind_backtrace) from [<c010b5b8>] (show_stack+0x10/0x14)
[<c010b5b8>] (show_stack) from [<c06bf2b4>] (dump_stack+0x88/0x9c)
[<c06bf2b4>] (dump_stack) from [<c011e044>] (__warn+0xd4/0xf0)
[<c011e044>] (__warn) from [<c011dbe4>] (warn_slowpath_fmt+0x48/0x6c)
[<c011dbe4>] (warn_slowpath_fmt) from [<c051ce20>] (i2c_transfer+0xe8/0xf4)
[<c051ce20>] (i2c_transfer) from [<c051ce78>] (i2c_transfer_buffer_flags+0x4c/0x70)
[<c051ce78>] (i2c_transfer_buffer_flags) from [<c046c2a4>] (regmap_i2c_write+0x14/0x30)
[<c046c2a4>] (regmap_i2c_write) from [<c0468180>] (_regmap_raw_write_impl+0x588/0x63c)
[<c0468180>] (_regmap_raw_write_impl) from [<c0468b50>] (regmap_write+0x3c/0x5c)
[<c0468b50>] (regmap_write) from [<c046f554>] (axp20x_power_off+0x2c/0x38)
[<c046f554>] (axp20x_power_off) from [<c013e8a4>] (sys_reboot+0x14c/0x1e0)
[<c013e8a4>] (sys_reboot) from [<c0101000>] (ret_fast_syscall+0x0/0x54)
Exception stack(0xef04ffa8 to 0xef04fff0)
ffa0: 00427954 00000000 fee1dead 28121969 4321fedc 16814300
ffc0: 00427954 00000000 00000000 00000058 bec15c78 00000000 bec15c10 004266f8
ffe0: 00000058 bec15b6c b6f69d45 b6eeb746
[/snip]

The enc28j60 module is SPI, so it has nothing to do with the message.

Any ideas where to look?

Päikest,
Priit :)

[Chen-Yu Tsai]

This looks like it's complaining that i2c-1 (i2c-mv64xxx) does not have
.master_xfer_atomic , which should be used in atomic contexts.

include/linux/i2c.h says:

@master_xfer_atomic: same as @master_xfer. Yet, only using atomic context
so e.g. PMICs can be accessed very late before shutdown. Optional.

ChenYu