/*
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* Generic DT helper functions for touchscreen 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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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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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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 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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"DT specifies parameters 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->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 DT 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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*
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* This function parses common DT properties for touchscreens and setups 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 via DT.
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*/
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void touchscreen_parse_properties(struct input_dev *input, bool multitouch)
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{
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struct device *dev = input->dev.parent;
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unsigned int axis;
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unsigned int 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 = multitouch ? ABS_MT_POSITION_X : ABS_X;
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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) + 1,
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&maximum) |
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touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
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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, maximum - 1, fuzz);
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axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
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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) + 1,
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&maximum) |
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touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
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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, 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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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, maximum, fuzz);
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}
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EXPORT_SYMBOL(touchscreen_parse_properties);
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