i2c: designware: Fix unbalanced suspended flag
authorRichard Fitzgerald <rf@opensource.cirrus.com>
Mon, 19 Dec 2022 13:01:45 +0000 (13:01 +0000)
committerWolfram Sang <wsa@kernel.org>
Mon, 9 Jan 2023 12:11:17 +0000 (13:11 +0100)
commit75507a319876aba88932e2c7dab58b6c22d89f6b
tree2c12e32118fc31fcd7e8462787cffddc71801e83
parentc8c37bc514514999e62a17e95160ed9ebf75ca8d
i2c: designware: Fix unbalanced suspended flag

Ensure that i2c_mark_adapter_suspended() is always balanced by a call to
i2c_mark_adapter_resumed().

dw_i2c_plat_resume() must always be called, so that
i2c_mark_adapter_resumed() is called. This is not compatible with
DPM_FLAG_MAY_SKIP_RESUME, so remove the flag.

Since the controller is always resumed on system resume the
dw_i2c_plat_complete() callback is redundant and has been removed.

The unbalanced suspended flag was introduced by commit c57813b8b288
("i2c: designware: Lock the adapter while setting the suspended flag")

Before that commit, the system and runtime PM used the same functions. The
DPM_FLAG_MAY_SKIP_RESUME was used to skip the system resume if the driver
had been in runtime-suspend. If system resume was skipped, the suspended
flag would be cleared by the next runtime resume. The check of the
suspended flag was _after_ the call to pm_runtime_get_sync() in
i2c_dw_xfer(). So either a system resume or a runtime resume would clear
the flag before it was checked.

Having introduced the unbalanced suspended flag with that commit, a further
commit 80704a84a9f8
("i2c: designware: Use the i2c_mark_adapter_suspended/resumed() helpers")

changed from using a local suspended flag to using the
i2c_mark_adapter_suspended/resumed() functions. These use a flag that is
checked by I2C core code before issuing the transfer to the bus driver, so
there was no opportunity for the bus driver to runtime resume itself before
the flag check.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: c57813b8b288 ("i2c: designware: Lock the adapter while setting the suspended flag")
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
drivers/i2c/busses/i2c-designware-platdrv.c