• Rafael J. Wysocki's avatar
    PM: i2c-designware-platdrv: Suspend/resume at the late/early stages · 54152772
    Rafael J. Wysocki authored
    As reported by Rajat Jain, there are problems when ACPI operation
    region handlers or similar, called at the ->resume_early() time, for
    I2C client devices try to access an I2C controller that has already
    been suspended at that point.  To avoid that, move the suspend/resume
    of i2c-designware-platdrv to the late/early stages, respectively.
    
    While at it, avoid resuming the device from runtime suspend in the
    driver's ->suspend callback which isn't particularly nice.  [A better
    approach would be to make the driver track the PM state of the device
    so that it doesn't need to resume it in ->suspend, so implement it.]
    
    First, drop dw_i2c_plat_suspend() added by commit a23318fe (i2c:
    designware: Fix system suspend) and rename dw_i2c_plat_runtime_suspend()
    back to dw_i2c_plat_suspend().
    
    Second, point the driver's ->late_suspend and ->early_resume
    callbacks, rather than its ->suspend and ->resume callbacks,
    to dw_i2c_plat_suspend() and dw_i2c_plat_resume(), respectively,
    so that they are not executed in parallel with each other, for
    example if runtime resume of the device takes place during system
    suspend.
    
    Finally, add "suspended" and "skip_resume" flags to struct dw_i2c_dev
    and make dw_i2c_plat_suspend() and dw_i2c_plat_resume() use them to
    avoid suspending or resuming the device twice in a row and to avoid
    resuming a previously runtime-suspended device during system resume.
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    Tested-by: default avatarJarkko Nikula <jarkko.nikula@linux.intel.com>
    Tested-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
    Tested-by: default avatarJohannes Stezenbach <js@sig21.net>
    Tested-by: default avatarRajat Jain <rajatja@google.com>
    Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
    54152772
i2c-designware-core.h 10.7 KB