drivers/input/touchscreen.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  *  Generic helper functions for touchscreens and other two-dimensional
0004  *  pointing devices
0005  *
0006  *  Copyright (c) 2014 Sebastian Reichel <sre@kernel.org>
0007  */
0008
0009 #include <linux/property.h>
0010 #include <linux/input.h>
0011 #include <linux/input/mt.h>
0012 #include <linux/input/touchscreen.h>
0013 #include <linux/module.h>
0014
0015 static bool touchscreen_get_prop_u32(struct device *dev,
0016                      const char *property,
0017                      unsigned int default_value,
0018                      unsigned int *value)
0019 {
0020     u32 val;
0021     int error;
0022
0023     error = device_property_read_u32(dev, property, &val);
0024     if (error) {
0025         *value = default_value;
0026         return false;
0027     }
0028
0029     *value = val;
0030     return true;
0031 }
0032
0033 static void touchscreen_set_params(struct input_dev *dev,
0034                    unsigned long axis,
0035                    int min, int max, int fuzz)
0036 {
0037     struct input_absinfo *absinfo;
0038
0039     if (!test_bit(axis, dev->absbit)) {
0040         dev_warn(&dev->dev,
0041              "Parameters are specified but the axis %lu is not set up\n",
0042              axis);
0043         return;
0044     }
0045
0046     absinfo = &dev->absinfo[axis];
0047     absinfo->minimum = min;
0048     absinfo->maximum = max;
0049     absinfo->fuzz = fuzz;
0050 }
0051
0052 /**
0053  * touchscreen_parse_properties - parse common touchscreen properties
0054  * @input: input device that should be parsed
0055  * @multitouch: specifies whether parsed properties should be applied to
0056  *  single-touch or multi-touch axes
0057  * @prop: pointer to a struct touchscreen_properties into which to store
0058  *  axis swap and invert info for use with touchscreen_report_x_y();
0059  *  or %NULL
0060  *
0061  * This function parses common properties for touchscreens and sets up the
0062  * input device accordingly. The function keeps previously set up default
0063  * values if no value is specified.
0064  */
0065 void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
0066                   struct touchscreen_properties *prop)
0067 {
0068     struct device *dev = input->dev.parent;
0069     struct input_absinfo *absinfo;
0070     unsigned int axis, axis_x, axis_y;
0071     unsigned int minimum, maximum, fuzz;
0072     bool data_present;
0073
0074     input_alloc_absinfo(input);
0075     if (!input->absinfo)
0076         return;
0077
0078     axis_x = multitouch ? ABS_MT_POSITION_X : ABS_X;
0079     axis_y = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
0080
0081     data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
0082                         input_abs_get_min(input, axis_x),
0083                         &minimum);
0084     data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-x",
0085                          input_abs_get_max(input,
0086                                    axis_x) + 1,
0087                          &maximum);
0088     data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
0089                          input_abs_get_fuzz(input, axis_x),
0090                          &fuzz);
0091     if (data_present)
0092         touchscreen_set_params(input, axis_x, minimum, maximum - 1, fuzz);
0093
0094     data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
0095                         input_abs_get_min(input, axis_y),
0096                         &minimum);
0097     data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-y",
0098                          input_abs_get_max(input,
0099                                    axis_y) + 1,
0100                          &maximum);
0101     data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
0102                          input_abs_get_fuzz(input, axis_y),
0103                          &fuzz);
0104     if (data_present)
0105         touchscreen_set_params(input, axis_y, minimum, maximum - 1, fuzz);
0106
0107     axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
0108     data_present = touchscreen_get_prop_u32(dev,
0109                         "touchscreen-max-pressure",
0110                         input_abs_get_max(input, axis),
0111                         &maximum);
0112     data_present |= touchscreen_get_prop_u32(dev,
0113                          "touchscreen-fuzz-pressure",
0114                          input_abs_get_fuzz(input, axis),
0115                          &fuzz);
0116     if (data_present)
0117         touchscreen_set_params(input, axis, 0, maximum, fuzz);
0118
0119     if (!prop)
0120         return;
0121
0122     prop->max_x = input_abs_get_max(input, axis_x);
0123     prop->max_y = input_abs_get_max(input, axis_y);
0124
0125     prop->invert_x =
0126         device_property_read_bool(dev, "touchscreen-inverted-x");
0127     if (prop->invert_x) {
0128         absinfo = &input->absinfo[axis_x];
0129         absinfo->maximum -= absinfo->minimum;
0130         absinfo->minimum = 0;
0131     }
0132
0133     prop->invert_y =
0134         device_property_read_bool(dev, "touchscreen-inverted-y");
0135     if (prop->invert_y) {
0136         absinfo = &input->absinfo[axis_y];
0137         absinfo->maximum -= absinfo->minimum;
0138         absinfo->minimum = 0;
0139     }
0140
0141     prop->swap_x_y =
0142         device_property_read_bool(dev, "touchscreen-swapped-x-y");
0143     if (prop->swap_x_y)
0144         swap(input->absinfo[axis_x], input->absinfo[axis_y]);
0145 }
0146 EXPORT_SYMBOL(touchscreen_parse_properties);
0147
0148 static void
0149 touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop,
0150                   unsigned int *x, unsigned int *y)
0151 {
0152     if (prop->invert_x)
0153         *x = prop->max_x - *x;
0154
0155     if (prop->invert_y)
0156         *y = prop->max_y - *y;
0157
0158     if (prop->swap_x_y)
0159         swap(*x, *y);
0160 }
0161
0162 /**
0163  * touchscreen_set_mt_pos - Set input_mt_pos coordinates
0164  * @pos: input_mt_pos to set coordinates of
0165  * @prop: pointer to a struct touchscreen_properties
0166  * @x: X coordinate to store in pos
0167  * @y: Y coordinate to store in pos
0168  *
0169  * Adjust the passed in x and y values applying any axis inversion and
0170  * swapping requested in the passed in touchscreen_properties and store
0171  * the result in a struct input_mt_pos.
0172  */
0173 void touchscreen_set_mt_pos(struct input_mt_pos *pos,
0174                 const struct touchscreen_properties *prop,
0175                 unsigned int x, unsigned int y)
0176 {
0177     touchscreen_apply_prop_to_x_y(prop, &x, &y);
0178     pos->x = x;
0179     pos->y = y;
0180 }
0181 EXPORT_SYMBOL(touchscreen_set_mt_pos);
0182
0183 /**
0184  * touchscreen_report_pos - Report touchscreen coordinates
0185  * @input: input_device to report coordinates for
0186  * @prop: pointer to a struct touchscreen_properties
0187  * @x: X coordinate to report
0188  * @y: Y coordinate to report
0189  * @multitouch: Report coordinates on single-touch or multi-touch axes
0190  *
0191  * Adjust the passed in x and y values applying any axis inversion and
0192  * swapping requested in the passed in touchscreen_properties and then
0193  * report the resulting coordinates on the input_dev's x and y axis.
0194  */
0195 void touchscreen_report_pos(struct input_dev *input,
0196                 const struct touchscreen_properties *prop,
0197                 unsigned int x, unsigned int y,
0198                 bool multitouch)
0199 {
0200     touchscreen_apply_prop_to_x_y(prop, &x, &y);
0201     input_report_abs(input, multitouch ? ABS_MT_POSITION_X : ABS_X, x);
0202     input_report_abs(input, multitouch ? ABS_MT_POSITION_Y : ABS_Y, y);
0203 }
0204 EXPORT_SYMBOL(touchscreen_report_pos);
0205
0206 MODULE_LICENSE("GPL v2");
0207 MODULE_DESCRIPTION("Helper functions for touchscreens and other devices");