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.

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