2 * Generic DT helper functions for touchscreen devices
4 * Copyright (c) 2014 Sebastian Reichel <sre@kernel.org>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
13 #include <linux/input.h>
14 #include <linux/input/mt.h>
15 #include <linux/input/touchscreen.h>
17 static bool touchscreen_get_prop_u32(struct device_node *np,
19 unsigned int default_value,
25 error = of_property_read_u32(np, property, &val);
27 *value = default_value;
35 static void touchscreen_set_params(struct input_dev *dev,
39 struct input_absinfo *absinfo;
41 if (!test_bit(axis, dev->absbit)) {
43 * Emit a warning only if the axis is not a multitouch
44 * axis, which might not be set by the driver.
46 if (!input_is_mt_axis(axis))
48 "DT specifies parameters but the axis is not set up\n");
52 absinfo = &dev->absinfo[axis];
53 absinfo->maximum = max;
58 * touchscreen_parse_of_params - parse common touchscreen DT properties
59 * @dev: device that should be parsed
61 * This function parses common DT properties for touchscreens and setups the
62 * input device accordingly. The function keeps previously setuped default
63 * values if no value is specified via DT.
65 void touchscreen_parse_of_params(struct input_dev *dev, bool multitouch)
67 struct device_node *np = dev->dev.parent->of_node;
69 unsigned int maximum, fuzz;
72 input_alloc_absinfo(dev);
76 axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
77 data_present = touchscreen_get_prop_u32(np, "touchscreen-size-x",
78 input_abs_get_max(dev, axis),
80 touchscreen_get_prop_u32(np, "touchscreen-fuzz-x",
81 input_abs_get_fuzz(dev, axis),
84 touchscreen_set_params(dev, axis, maximum, fuzz);
86 axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
87 data_present = touchscreen_get_prop_u32(np, "touchscreen-size-y",
88 input_abs_get_max(dev, axis),
90 touchscreen_get_prop_u32(np, "touchscreen-fuzz-y",
91 input_abs_get_fuzz(dev, axis),
94 touchscreen_set_params(dev, axis, maximum, fuzz);
96 axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
97 data_present = touchscreen_get_prop_u32(np, "touchscreen-max-pressure",
98 input_abs_get_max(dev, axis),
100 touchscreen_get_prop_u32(np, "touchscreen-fuzz-pressure",
101 input_abs_get_fuzz(dev, axis),
104 touchscreen_set_params(dev, axis, maximum, fuzz);
106 EXPORT_SYMBOL(touchscreen_parse_of_params);