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![Nathan Chancellor](/assets/img/avatar_default.png)
A new warning in clang points out a few places in this driver where a bitwise OR is being used with boolean types: drivers/input/touchscreen.c:81:17: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical] data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x", ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This use of a bitwise OR is intentional, as bitwise operations do not short circuit, which allows all the calls to touchscreen_get_prop_u32() to happen so that the last parameter is initialized while coalescing the results of the calls to make a decision after they are all evaluated. To make this clearer to the compiler, use the '|=' operator to assign the result of each touchscreen_get_prop_u32() call to data_present, which keeps the meaning of the code the same but makes it obvious that every one of these calls is expected to happen. Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reported-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20211014205757.3474635-1-nathan@kernel.org Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
207 lines
6 KiB
C
207 lines
6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Generic helper functions for touchscreens and other two-dimensional
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* pointing devices
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*
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* Copyright (c) 2014 Sebastian Reichel <sre@kernel.org>
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*/
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#include <linux/property.h>
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#include <linux/input.h>
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#include <linux/input/mt.h>
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#include <linux/input/touchscreen.h>
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#include <linux/module.h>
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static bool touchscreen_get_prop_u32(struct device *dev,
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const char *property,
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unsigned int default_value,
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unsigned int *value)
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{
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u32 val;
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int error;
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error = device_property_read_u32(dev, property, &val);
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if (error) {
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*value = default_value;
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return false;
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}
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*value = val;
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return true;
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}
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static void touchscreen_set_params(struct input_dev *dev,
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unsigned long axis,
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int min, int max, int fuzz)
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{
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struct input_absinfo *absinfo;
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if (!test_bit(axis, dev->absbit)) {
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dev_warn(&dev->dev,
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"Parameters are specified but the axis %lu is not set up\n",
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axis);
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return;
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}
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absinfo = &dev->absinfo[axis];
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absinfo->minimum = min;
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absinfo->maximum = max;
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absinfo->fuzz = fuzz;
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}
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/**
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* touchscreen_parse_properties - parse common touchscreen properties
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* @input: input device that should be parsed
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* @multitouch: specifies whether parsed properties should be applied to
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* single-touch or multi-touch axes
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* @prop: pointer to a struct touchscreen_properties into which to store
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* axis swap and invert info for use with touchscreen_report_x_y();
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* or %NULL
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*
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* This function parses common properties for touchscreens and sets up the
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* input device accordingly. The function keeps previously set up default
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* values if no value is specified.
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*/
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void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
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struct touchscreen_properties *prop)
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{
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struct device *dev = input->dev.parent;
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struct input_absinfo *absinfo;
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unsigned int axis, axis_x, axis_y;
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unsigned int minimum, maximum, fuzz;
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bool data_present;
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input_alloc_absinfo(input);
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if (!input->absinfo)
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return;
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axis_x = multitouch ? ABS_MT_POSITION_X : ABS_X;
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axis_y = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
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data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
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input_abs_get_min(input, axis_x),
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&minimum);
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data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-x",
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input_abs_get_max(input,
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axis_x) + 1,
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&maximum);
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data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
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input_abs_get_fuzz(input, axis_x),
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&fuzz);
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if (data_present)
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touchscreen_set_params(input, axis_x, minimum, maximum - 1, fuzz);
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data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
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input_abs_get_min(input, axis_y),
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&minimum);
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data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-y",
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input_abs_get_max(input,
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axis_y) + 1,
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&maximum);
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data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
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input_abs_get_fuzz(input, axis_y),
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&fuzz);
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if (data_present)
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touchscreen_set_params(input, axis_y, minimum, maximum - 1, fuzz);
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axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
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data_present = touchscreen_get_prop_u32(dev,
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"touchscreen-max-pressure",
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input_abs_get_max(input, axis),
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&maximum);
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data_present |= touchscreen_get_prop_u32(dev,
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"touchscreen-fuzz-pressure",
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input_abs_get_fuzz(input, axis),
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&fuzz);
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if (data_present)
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touchscreen_set_params(input, axis, 0, maximum, fuzz);
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if (!prop)
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return;
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prop->max_x = input_abs_get_max(input, axis_x);
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prop->max_y = input_abs_get_max(input, axis_y);
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prop->invert_x =
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device_property_read_bool(dev, "touchscreen-inverted-x");
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if (prop->invert_x) {
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absinfo = &input->absinfo[axis_x];
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absinfo->maximum -= absinfo->minimum;
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absinfo->minimum = 0;
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}
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prop->invert_y =
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device_property_read_bool(dev, "touchscreen-inverted-y");
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if (prop->invert_y) {
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absinfo = &input->absinfo[axis_y];
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absinfo->maximum -= absinfo->minimum;
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absinfo->minimum = 0;
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}
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prop->swap_x_y =
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device_property_read_bool(dev, "touchscreen-swapped-x-y");
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if (prop->swap_x_y)
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swap(input->absinfo[axis_x], input->absinfo[axis_y]);
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}
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EXPORT_SYMBOL(touchscreen_parse_properties);
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static void
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touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop,
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unsigned int *x, unsigned int *y)
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{
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if (prop->invert_x)
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*x = prop->max_x - *x;
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if (prop->invert_y)
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*y = prop->max_y - *y;
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if (prop->swap_x_y)
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swap(*x, *y);
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}
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/**
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* touchscreen_set_mt_pos - Set input_mt_pos coordinates
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* @pos: input_mt_pos to set coordinates of
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* @prop: pointer to a struct touchscreen_properties
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* @x: X coordinate to store in pos
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* @y: Y coordinate to store in pos
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*
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* Adjust the passed in x and y values applying any axis inversion and
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* swapping requested in the passed in touchscreen_properties and store
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* the result in a struct input_mt_pos.
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*/
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void touchscreen_set_mt_pos(struct input_mt_pos *pos,
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const struct touchscreen_properties *prop,
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unsigned int x, unsigned int y)
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{
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touchscreen_apply_prop_to_x_y(prop, &x, &y);
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pos->x = x;
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pos->y = y;
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}
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EXPORT_SYMBOL(touchscreen_set_mt_pos);
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/**
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* touchscreen_report_pos - Report touchscreen coordinates
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* @input: input_device to report coordinates for
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* @prop: pointer to a struct touchscreen_properties
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* @x: X coordinate to report
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* @y: Y coordinate to report
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* @multitouch: Report coordinates on single-touch or multi-touch axes
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*
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* Adjust the passed in x and y values applying any axis inversion and
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* swapping requested in the passed in touchscreen_properties and then
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* report the resulting coordinates on the input_dev's x and y axis.
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*/
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void touchscreen_report_pos(struct input_dev *input,
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const struct touchscreen_properties *prop,
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unsigned int x, unsigned int y,
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bool multitouch)
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{
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touchscreen_apply_prop_to_x_y(prop, &x, &y);
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input_report_abs(input, multitouch ? ABS_MT_POSITION_X : ABS_X, x);
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input_report_abs(input, multitouch ? ABS_MT_POSITION_Y : ABS_Y, y);
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}
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EXPORT_SYMBOL(touchscreen_report_pos);
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("Helper functions for touchscreens and other devices");
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