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kernel/linux-rt-4.4.41/drivers/input/touchscreen/of_touchscreen.c 2.95 KB
5113f6f70   김현기   kernel add
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  /*
   *  Generic DT helper functions for touchscreen devices
   *
   *  Copyright (c) 2014 Sebastian Reichel <sre@kernel.org>
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License version 2 as
   *  published by the Free Software Foundation.
   *
   */
  
  #include <linux/property.h>
  #include <linux/input.h>
  #include <linux/input/mt.h>
  #include <linux/input/touchscreen.h>
  
  static bool touchscreen_get_prop_u32(struct device *dev,
  				     const char *property,
  				     unsigned int default_value,
  				     unsigned int *value)
  {
  	u32 val;
  	int error;
  
  	error = device_property_read_u32(dev, property, &val);
  	if (error) {
  		*value = default_value;
  		return false;
  	}
  
  	*value = val;
  	return true;
  }
  
  static void touchscreen_set_params(struct input_dev *dev,
  				   unsigned long axis,
  				   int max, int fuzz)
  {
  	struct input_absinfo *absinfo;
  
  	if (!test_bit(axis, dev->absbit)) {
  		dev_warn(&dev->dev,
  			 "DT specifies parameters but the axis %lu is not set up
  ",
  			 axis);
  		return;
  	}
  
  	absinfo = &dev->absinfo[axis];
  	absinfo->maximum = max;
  	absinfo->fuzz = fuzz;
  }
  
  /**
   * touchscreen_parse_properties - parse common touchscreen DT properties
   * @input: input device that should be parsed
   * @multitouch: specifies whether parsed properties should be applied to
   *	single-touch or multi-touch axes
   *
   * This function parses common DT properties for touchscreens and setups the
   * input device accordingly. The function keeps previously set up default
   * values if no value is specified via DT.
   */
  void touchscreen_parse_properties(struct input_dev *input, bool multitouch)
  {
  	struct device *dev = input->dev.parent;
  	unsigned int axis;
  	unsigned int maximum, fuzz;
  	bool data_present;
  
  	input_alloc_absinfo(input);
  	if (!input->absinfo)
  		return;
  
  	axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
  	data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-x",
  						input_abs_get_max(input,
  								  axis) + 1,
  						&maximum) |
  		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
  						input_abs_get_fuzz(input, axis),
  						&fuzz);
  	if (data_present)
  		touchscreen_set_params(input, axis, maximum - 1, fuzz);
  
  	axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
  	data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-y",
  						input_abs_get_max(input,
  								  axis) + 1,
  						&maximum) |
  		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
  						input_abs_get_fuzz(input, axis),
  						&fuzz);
  	if (data_present)
  		touchscreen_set_params(input, axis, maximum - 1, fuzz);
  
  	axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
  	data_present = touchscreen_get_prop_u32(dev,
  						"touchscreen-max-pressure",
  						input_abs_get_max(input, axis),
  						&maximum) |
  		       touchscreen_get_prop_u32(dev,
  						"touchscreen-fuzz-pressure",
  						input_abs_get_fuzz(input, axis),
  						&fuzz);
  	if (data_present)
  		touchscreen_set_params(input, axis, maximum, fuzz);
  }
  EXPORT_SYMBOL(touchscreen_parse_properties);