Input: add input_copy_abs() function

Add a new helper function to copy absinfo from one input_dev to
another input_dev.

This is useful to e.g. setup a pen/stylus input-device for combined
touchscreen/pen hardware where the pen uses the same coordinates as
the touchscreen.

Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220131143539.109142-2-hdegoede@redhat.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Hans de Goede 2022-02-28 22:58:28 -08:00 committed by Dmitry Torokhov
parent 3f9ed5c2fe
commit cb66b9ba5c
2 changed files with 38 additions and 0 deletions

View File

@ -526,6 +526,42 @@ void input_set_abs_params(struct input_dev *dev, unsigned int axis,
}
EXPORT_SYMBOL(input_set_abs_params);
/**
* input_copy_abs - Copy absinfo from one input_dev to another
* @dst: Destination input device to copy the abs settings to
* @dst_axis: ABS_* value selecting the destination axis
* @src: Source input device to copy the abs settings from
* @src_axis: ABS_* value selecting the source axis
*
* Set absinfo for the selected destination axis by copying it from
* the specified source input device's source axis.
* This is useful to e.g. setup a pen/stylus input-device for combined
* touchscreen/pen hardware where the pen uses the same coordinates as
* the touchscreen.
*/
void input_copy_abs(struct input_dev *dst, unsigned int dst_axis,
const struct input_dev *src, unsigned int src_axis)
{
/* src must have EV_ABS and src_axis set */
if (WARN_ON(!(test_bit(EV_ABS, src->evbit) &&
test_bit(src_axis, src->absbit))))
return;
/*
* input_alloc_absinfo() may have failed for the source. Our caller is
* expected to catch this when registering the input devices, which may
* happen after the input_copy_abs() call.
*/
if (!src->absinfo)
return;
input_set_capability(dst, EV_ABS, dst_axis);
if (!dst->absinfo)
return;
dst->absinfo[dst_axis] = src->absinfo[src_axis];
}
EXPORT_SYMBOL(input_copy_abs);
/**
* input_grab_device - grabs device for exclusive use

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@ -475,6 +475,8 @@ static inline void input_set_events_per_packet(struct input_dev *dev, int n_even
void input_alloc_absinfo(struct input_dev *dev);
void input_set_abs_params(struct input_dev *dev, unsigned int axis,
int min, int max, int fuzz, int flat);
void input_copy_abs(struct input_dev *dst, unsigned int dst_axis,
const struct input_dev *src, unsigned int src_axis);
#define INPUT_GENERATE_ABS_ACCESSORS(_suffix, _item) \
static inline int input_abs_get_##_suffix(struct input_dev *dev, \