diff options
author | Anssi Hannula <anssi.hannula@gmail.com> | 2006-07-19 01:44:22 -0400 |
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committer | Dmitry Torokhov <dtor@insightbb.com> | 2006-07-19 01:44:22 -0400 |
commit | 8b8277a17477de38d8df6783e8221aed55bab300 (patch) | |
tree | 20988680a957d453d273d7b9a86e929dc19c73e9 /include/linux | |
parent | bb3caf7f438a67452f5cf4773ca1bf82260bbbad (diff) |
Input: update the force feedback documentation
Signed-off-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'include/linux')
-rw-r--r-- | include/linux/input.h | 175 |
1 files changed, 122 insertions, 53 deletions
diff --git a/include/linux/input.h b/include/linux/input.h index 4405d028354..a7a1f55a5ee 100644 --- a/include/linux/input.h +++ b/include/linux/input.h @@ -667,98 +667,167 @@ struct input_absinfo { /* * Structures used in ioctls to upload effects to a device - * The first structures are not passed directly by using ioctls. - * They are sub-structures of the actually sent structure (called ff_effect) + * They are pieces of a bigger structure (called ff_effect) */ +/* + * All duration values are expressed in ms. Values above 32767 ms (0x7fff) + * should not be used and have unspecified results. + */ + +/** + * struct ff_replay - defines scheduling of the effect + * @length: duration of the effect + * @delay: delay before effect should start playing + */ struct ff_replay { - __u16 length; /* Duration of an effect in ms. All other times are also expressed in ms */ - __u16 delay; /* Time to wait before to start playing an effect */ + __u16 length; + __u16 delay; }; +/** + * struct ff_trigger - defines what triggers the effect + * @button: number of the button triggering the effect + * @interval: controls how soon the effect can be re-triggered + */ struct ff_trigger { - __u16 button; /* Number of button triggering an effect */ - __u16 interval; /* Time to wait before an effect can be re-triggered (ms) */ + __u16 button; + __u16 interval; }; +/** + * struct ff_envelope - generic effect envelope + * @attack_length: duration of the attack (ms) + * @attack_level: level at the beginning of the attack + * @fade_length: duration of fade (ms) + * @fade_level: level at the end of fade + * + * The @attack_level and @fade_level are absolute values; when applying + * envelope force-feedback core will convert to positive/negative + * value based on polarity of the default level of the effect. + * Valid range for the attack and fade levels is 0x0000 - 0x7fff + */ struct ff_envelope { - __u16 attack_length; /* Duration of attack (ms) */ - __u16 attack_level; /* Level at beginning of attack */ - __u16 fade_length; /* Duration of fade (ms) */ - __u16 fade_level; /* Level at end of fade */ + __u16 attack_length; + __u16 attack_level; + __u16 fade_length; + __u16 fade_level; }; -/* FF_CONSTANT */ +/** + * struct ff_constant_effect - defines parameters of a constant effect + * @level: strength of the effect; may be negative + * @envelope: envelope data + */ struct ff_constant_effect { - __s16 level; /* Strength of effect. Negative values are OK */ + __s16 level; struct ff_envelope envelope; }; -/* FF_RAMP */ +/** + * struct ff_ramp_effect - defines parameters of a ramp effect + * @start_level: beginning strength of the effect; may be negative + * @end_level: final strength of the effect; may be negative + * @envelope: envelope data + */ struct ff_ramp_effect { __s16 start_level; __s16 end_level; struct ff_envelope envelope; }; -/* FF_SPRING of FF_FRICTION */ +/** + * struct ff_condition_effect - defines a spring or friction effect + * @right_saturation: maximum level when joystick moved all way to the right + * @left_saturation: same for the left side + * @right_coeff: controls how fast the force grows when the joystick moves + * to the right + * @left_coeff: same for the left side + * @deadband: size of the dead zone, where no force is produced + * @center: position of the dead zone + */ struct ff_condition_effect { - __u16 right_saturation; /* Max level when joystick is on the right */ - __u16 left_saturation; /* Max level when joystick in on the left */ + __u16 right_saturation; + __u16 left_saturation; - __s16 right_coeff; /* Indicates how fast the force grows when the - joystick moves to the right */ - __s16 left_coeff; /* Same for left side */ - - __u16 deadband; /* Size of area where no force is produced */ - __s16 center; /* Position of dead zone */ + __s16 right_coeff; + __s16 left_coeff; + __u16 deadband; + __s16 center; }; -/* FF_PERIODIC */ +/** + * struct ff_periodic_effect - defines parameters of a periodic effect + * @waveform: kind of the effect (wave) + * @period: period of the wave (ms) + * @magnitude: peak value + * @offset: mean value of the wave (roughly) + * @phase: 'horizontal' shift + * @envelope: envelope data + * @custom_len: number of samples (FF_CUSTOM only) + * @custom_data: buffer of samples (FF_CUSTOM only) + * + * Known waveforms - FF_SQUARE, FF_TRIANGLE, FF_SINE, FF_SAW_UP, + * FF_SAW_DOWN, FF_CUSTOM. The exact syntax FF_CUSTOM is undefined + * for the time being as no driver supports it yet. + * + * Note: the data pointed by custom_data is copied by the driver. + * You can therefore dispose of the memory after the upload/update. + */ struct ff_periodic_effect { - __u16 waveform; /* Kind of wave (sine, square...) */ - __u16 period; /* in ms */ - __s16 magnitude; /* Peak value */ - __s16 offset; /* Mean value of wave (roughly) */ - __u16 phase; /* 'Horizontal' shift */ + __u16 waveform; + __u16 period; + __s16 magnitude; + __s16 offset; + __u16 phase; struct ff_envelope envelope; -/* Only used if waveform == FF_CUSTOM */ - __u32 custom_len; /* Number of samples */ - __s16 *custom_data; /* Buffer of samples */ -/* Note: the data pointed by custom_data is copied by the driver. You can - * therefore dispose of the memory after the upload/update */ + __u32 custom_len; + __s16 *custom_data; }; -/* FF_RUMBLE */ -/* Some rumble pads have two motors of different weight. - strong_magnitude represents the magnitude of the vibration generated - by the heavy motor. -*/ +/** + * struct ff_rumble_effect - defines parameters of a periodic effect + * @strong_magnitude: magnitude of the heavy motor + * @weak_magnitude: magnitude of the light one + * + * Some rumble pads have two motors of different weight. Strong_magnitude + * represents the magnitude of the vibration generated by the heavy one. + */ struct ff_rumble_effect { - __u16 strong_magnitude; /* Magnitude of the heavy motor */ - __u16 weak_magnitude; /* Magnitude of the light one */ + __u16 strong_magnitude; + __u16 weak_magnitude; }; -/* - * Structure sent through ioctl from the application to the driver +/** + * struct ff_effect - defines force feedback effect + * @type: type of the effect (FF_CONSTANT, FF_PERIODIC, FF_RAMP, FF_SPRING, + * FF_FRICTION, FF_DAMPER, FF_RUMBLE, FF_INERTIA, or FF_CUSTOM) + * @id: an unique id assigned to an effect + * @direction: direction of the effect + * @trigger: trigger conditions (struct ff_trigger) + * @replay: scheduling of the effect (struct ff_replay) + * @u: effect-specific structure (one of ff_constant_effect, ff_ramp_effect, + * ff_periodic_effect, ff_condition_effect, ff_rumble_effect) further + * defining effect parameters + * + * This structure is sent through ioctl from the application to the driver. + * To create a new effect aplication should set its @id to -1; the kernel + * will return assigned @id which can later be used to update or delete + * this effect. + * + * Direction of the effect is encoded as follows: + * 0 deg -> 0x0000 (down) + * 90 deg -> 0x4000 (left) + * 180 deg -> 0x8000 (up) + * 270 deg -> 0xC000 (right) */ struct ff_effect { __u16 type; -/* Following field denotes the unique id assigned to an effect. - * If user sets if to -1, a new effect is created, and its id is returned in the same field - * Else, the user sets it to the effect id it wants to update. - */ __s16 id; - - __u16 direction; /* Direction. 0 deg -> 0x0000 (down) - 90 deg -> 0x4000 (left) - 180 deg -> 0x8000 (up) - 270 deg -> 0xC000 (right) - */ - + __u16 direction; struct ff_trigger trigger; struct ff_replay replay; |