Input: implement new force feedback interface

Implement a new force feedback interface, in which all non-driver-specific
operations are separated to a common module. This includes handling effect
type validations, locking, etc.

The effects are now file descriptor specific instead of the previous strange
half-process half-fd specific behaviour. The effect memory of devices is not
emptied if the root user opens and closes the device while another user is
using effects. This is a minor change and most likely no force feedback
aware programs are affected by this negatively.

Otherwise the userspace interface is left unaltered.

Signed-off-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 61 insertions, 0 deletions

diff --git a/include/linux/input.h b/include/linux/input.h
index b3253ab72ff..81c6ea5afed 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -784,6 +784,9 @@ struct ff_effect {
 #define FF_INERTIA      0x56
 #define FF_RAMP         0x57
 
+#define FF_EFFECT_MIN   FF_RUMBLE
+#define FF_EFFECT_MAX   FF_RAMP
+
 /*
  * Force feedback periodic effect types
  */
@@ -795,6 +798,9 @@ struct ff_effect {
 #define FF_SAW_DOWN     0x5c
 #define FF_CUSTOM       0x5d
 
+#define FF_WAVEFORM_MIN FF_SQUARE
+#define FF_WAVEFORM_MAX FF_CUSTOM
+
 /*
  * Set ff device properties
  */
@@ -870,6 +876,8 @@ struct input_dev {
         unsigned int keycodesize;
         void *keycode;
 
+        struct ff_device *ff;
+
         unsigned int repeat_key;
         struct timer_list timer;
 
@@ -1108,5 +1116,58 @@ static inline void input_set_abs_params(struct input_dev *dev, int axis, int min
 
 extern struct class input_class;
 
+/**
+ * struct ff_device - force-feedback part of an input device
+ * @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: 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 effcet is automatically erased
+ *
+ * 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.
+ */
+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[NBITS(FF_MAX)];
+
+        struct mutex mutex;
+
+        int max_effects;
+        struct ff_effect *effects;
+        struct file *effect_owners[];
+};
+
+int input_ff_create(struct input_dev *dev, int max_effects);
+void input_ff_destroy(struct input_dev *dev);
+
+int input_ff_event(struct input_dev *dev, unsigned int type, unsigned int code, int value);
+
+int input_ff_upload(struct input_dev *dev, struct ff_effect *effect, struct file *file);
+int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file);
+
 #endif
 #endif