1. 根目录:
2. drivers
3. input
4. touchscreen
5. jornada720_ts.c

/*
 * drivers/input/touchscreen/jornada720_ts.c
 *
 * Copyright (C) 2007 Kristoffer Ericson <Kristoffer.Ericson@gmail.com>
 *
 *  Copyright (C) 2006 Filip Zyzniewski <filip.zyzniewski@tefnet.pl>
 *  based on HP Jornada 56x touchscreen driver by Alex Lange <chicken@handhelds.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.
 *
 * HP Jornada 710/720/729 Touchscreen Driver
 */

#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <mach/jornada720.h>
#include <mach/irqs.h>

MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson@gmail.com>");
MODULE_DESCRIPTION("HP Jornada 710/720/728 touchscreen driver");
MODULE_LICENSE("GPL v2");

struct jornada_ts {
	struct input_dev *dev;
	int x_data[4];		/* X sample values */
	int y_data[4];		/* Y sample values */
};

static void jornada720_ts_collect_data(struct jornada_ts *jornada_ts)
{
	/* 3 low word X samples */
	jornada_ts->x_data[0] = jornada_ssp_byte(TXDUMMY);
	jornada_ts->x_data[1] = jornada_ssp_byte(TXDUMMY);
	jornada_ts->x_data[2] = jornada_ssp_byte(TXDUMMY);

	/* 3 low word Y samples */
	jornada_ts->y_data[0] = jornada_ssp_byte(TXDUMMY);
	jornada_ts->y_data[1] = jornada_ssp_byte(TXDUMMY);
	jornada_ts->y_data[2] = jornada_ssp_byte(TXDUMMY);

	/* combined x samples bits */
	jornada_ts->x_data[3] = jornada_ssp_byte(TXDUMMY);

	/* combined y samples bits */
	jornada_ts->y_data[3] = jornada_ssp_byte(TXDUMMY);
}

static int jornada720_ts_average(int coords[4])
{
	int coord, high_bits = coords[3];

	coord  = coords[0] | ((high_bits & 0x03) << 8);
	coord += coords[1] | ((high_bits & 0x0c) << 6);
	coord += coords[2] | ((high_bits & 0x30) << 4);

	return coord / 3;
}

static irqreturn_t jornada720_ts_interrupt(int irq, void *dev_id)
{
	struct platform_device *pdev = dev_id;
	struct jornada_ts *jornada_ts = platform_get_drvdata(pdev);
	struct input_dev *input = jornada_ts->dev;
	int x, y;

	/* If GPIO_GPIO9 is set to high then report pen up */
	if (GPLR & GPIO_GPIO(9)) {
		input_report_key(input, BTN_TOUCH, 0);
		input_sync(input);
	} else {
		jornada_ssp_start();

		/* proper reply to request is always TXDUMMY */
		if (jornada_ssp_inout(GETTOUCHSAMPLES) == TXDUMMY) {
			jornada720_ts_collect_data(jornada_ts);

			x = jornada720_ts_average(jornada_ts->x_data);
			y = jornada720_ts_average(jornada_ts->y_data);

			input_report_key(input, BTN_TOUCH, 1);
			input_report_abs(input, ABS_X, x);
			input_report_abs(input, ABS_Y, y);
			input_sync(input);
		}

		jornada_ssp_end();
	}

	return IRQ_HANDLED;
}

static int jornada720_ts_probe(struct platform_device *pdev)
{
	struct jornada_ts *jornada_ts;
	struct input_dev *input_dev;
	int error;

	jornada_ts = devm_kzalloc(&pdev->dev, sizeof(*jornada_ts), GFP_KERNEL);
	if (!jornada_ts)
		return -ENOMEM;

	input_dev = devm_input_allocate_device(&pdev->dev);
	if (!input_dev)
		return -ENOMEM;

	platform_set_drvdata(pdev, jornada_ts);

	jornada_ts->dev = input_dev;

	input_dev->name = "HP Jornada 7xx Touchscreen";
	input_dev->phys = "jornadats/input0";
	input_dev->id.bustype = BUS_HOST;
	input_dev->dev.parent = &pdev->dev;

	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
	input_set_abs_params(input_dev, ABS_X, 270, 3900, 0, 0);
	input_set_abs_params(input_dev, ABS_Y, 180, 3700, 0, 0);

	error = devm_request_irq(&pdev->dev, IRQ_GPIO9,
				 jornada720_ts_interrupt,
				 IRQF_TRIGGER_RISING,
				 "HP7XX Touchscreen driver", pdev);
	if (error) {
		dev_err(&pdev->dev, "HP7XX TS : Unable to acquire irq!\n");
		return error;
	}

	error = input_register_device(jornada_ts->dev);
	if (error)
		return error;

	return 0;
}

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:jornada_ts");

static struct platform_driver jornada720_ts_driver = {
	.probe		= jornada720_ts_probe,
	.driver		= {
		.name	= "jornada_ts",
	},
};
module_platform_driver(jornada720_ts_driver);