• Jacek Anaszewski's avatar
    leds: implement sysfs interface locking mechanism · acd899e4
    Jacek Anaszewski authored
    Add a mechanism for locking LED subsystem sysfs interface.
    This patch prepares ground for addition of LED Flash Class
    extension, whose API will be integrated with V4L2 Flash API.
    Such a fusion enforces introducing a locking scheme, which
    will secure consistent access to the LED Flash Class device.
    
    The mechanism being introduced allows for disabling LED
    subsystem sysfs interface by calling led_sysfs_disable function
    and enabling it by calling led_sysfs_enable. The functions
    alter the LED_SYSFS_DISABLE flag state and must be called
    under mutex lock. The state of the lock is checked with use
    of led_sysfs_is_disabled function. Such a design allows for
    providing immediate feedback to the user space on whether
    the LED Flash Class device is available or is under V4L2 Flash
    sub-device control.
    Signed-off-by: default avatarJacek Anaszewski <j.anaszewski@samsung.com>
    Acked-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
    Cc: Richard Purdie <rpurdie@rpsys.net>
    Signed-off-by: default avatarBryan Wu <cooloney@gmail.com>
    acd899e4
led-triggers.c 8.54 KB