• Richard Fitzgerald's avatar
    i2c: designware: Fix unbalanced suspended flag · 75507a31
    Richard Fitzgerald authored
    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 c57813b8
    ("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 80704a84
    ("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: default avatarRichard Fitzgerald <rf@opensource.cirrus.com>
    Fixes: c57813b8 ("i2c: designware: Lock the adapter while setting the suspended flag")
    Reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
    Acked-by: default avatarJarkko Nikula <jarkko.nikula@linux.intel.com>
    Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
    75507a31
i2c-designware-platdrv.c 11.4 KB