88 lines
2.4 KiB
C
88 lines
2.4 KiB
C
/*
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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/of.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 u32 of_get_optional_u32(struct device_node *np,
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const char *property)
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{
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u32 val = 0;
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of_property_read_u32(np, property, &val);
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return val;
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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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/*
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* Emit a warning only if the axis is not a multitouch
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* axis, which might not be set by the driver.
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*/
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if (!input_is_mt_axis(axis))
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dev_warn(&dev->dev,
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"DT specifies parameters but the axis is not set up\n");
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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_of_params - parse common touchscreen DT properties
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* @dev: device that should be parsed
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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 setuped default
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* values if no value is specified via DT.
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*/
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void touchscreen_parse_of_params(struct input_dev *dev)
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{
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struct device_node *np = dev->dev.parent->of_node;
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u32 maximum, fuzz;
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input_alloc_absinfo(dev);
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if (!dev->absinfo)
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return;
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maximum = of_get_optional_u32(np, "touchscreen-size-x");
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fuzz = of_get_optional_u32(np, "touchscreen-fuzz-x");
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if (maximum || fuzz) {
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touchscreen_set_params(dev, ABS_X, maximum, fuzz);
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touchscreen_set_params(dev, ABS_MT_POSITION_X, maximum, fuzz);
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}
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maximum = of_get_optional_u32(np, "touchscreen-size-y");
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fuzz = of_get_optional_u32(np, "touchscreen-fuzz-y");
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if (maximum || fuzz) {
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touchscreen_set_params(dev, ABS_Y, maximum, fuzz);
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touchscreen_set_params(dev, ABS_MT_POSITION_Y, maximum, fuzz);
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}
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maximum = of_get_optional_u32(np, "touchscreen-max-pressure");
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fuzz = of_get_optional_u32(np, "touchscreen-fuzz-pressure");
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if (maximum || fuzz) {
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touchscreen_set_params(dev, ABS_PRESSURE, maximum, fuzz);
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touchscreen_set_params(dev, ABS_MT_PRESSURE, maximum, fuzz);
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}
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}
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EXPORT_SYMBOL(touchscreen_parse_of_params);
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