centos man page for struct_ff_device

STRUCT 
FF_DEVICE(9)						  Input Subsystem					       STRUCT FF_DEVICE(9)

NAME
       struct_ff_device - force-feedback part of an input device

SYNOPSIS
       struct ff_device {
	 int (* upload) (struct input_dev *dev, struct ff_effect *effect,struct ff_effect *old);
	 int (* erase) (struct input_dev *dev, int effect_id);
	 int (* playback) (struct input_dev *dev, int effect_id, int value);
	 void (* set_gain) (struct input_dev *dev, u16 gain);
	 void (* set_autocenter) (struct input_dev *dev, u16 magnitude);
	 void (* destroy) (struct ff_device *);
	 void * private;
	 unsigned long ffbit[BITS_TO_LONGS(FF_CNT)];
	 struct mutex mutex;
	 int max_effects;
	 struct ff_effect * effects;
	 struct file * effect_owners[];
       };

MEMBERS
       upload
	   Called to upload an new effect into device

       erase
	   Called to erase an effect from device

       playback
	   Called to request device to start playing specified effect

       set_gain
	   Called to set specified gain

       set_autocenter
	   Called to auto-center device

       destroy
	   called by input core when parent input device is being destroyed

       private
	   driver-specific data, will be freed automatically

       ffbit[BITS_TO_LONGS(FF_CNT)]
	   bitmap of force feedback capabilities truly supported by device (not emulated like ones in input_dev->ffbit)

       mutex
	   mutex for serializing access to the device

       max_effects
	   maximum number of effects supported by device

       effects
	   pointer to an array of effects currently loaded into device

       effect_owners[]
	   array of effect owners; when file handle owning an effect gets closed the effect is automatically erased

DESCRIPTION
       Every force-feedback device must implement upload and playback methods; erase is optional.  set_gain and set_autocenter need only be
       implemented if driver sets up FF_GAIN and FF_AUTOCENTER bits.

       Note that playback, set_gain and set_autocenter are called with dev->event_lock spinlock held and interrupts off and thus may not sleep.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014						       STRUCT FF_DEVICE(9)