linux/drivers/input/touchscreen/pcap_ts.c
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   1/*
   2 * Driver for Motorola PCAP2 touchscreen as found in the EZX phone platform.
   3 *
   4 *  Copyright (C) 2006 Harald Welte <laforge@openezx.org>
   5 *  Copyright (C) 2009 Daniel Ribeiro <drwyrm@gmail.com>
   6 *
   7 *  This program is free software; you can redistribute it and/or modify
   8 *  it under the terms of the GNU General Public License version 2 as
   9 *  published by the Free Software Foundation.
  10 *
  11 */
  12
  13#include <linux/module.h>
  14#include <linux/fs.h>
  15#include <linux/string.h>
  16#include <linux/slab.h>
  17#include <linux/pm.h>
  18#include <linux/timer.h>
  19#include <linux/interrupt.h>
  20#include <linux/platform_device.h>
  21#include <linux/input.h>
  22#include <linux/mfd/ezx-pcap.h>
  23
  24struct pcap_ts {
  25        struct pcap_chip *pcap;
  26        struct input_dev *input;
  27        struct delayed_work work;
  28        u16 x, y;
  29        u16 pressure;
  30        u8 read_state;
  31};
  32
  33#define SAMPLE_DELAY    20 /* msecs */
  34
  35#define X_AXIS_MIN      0
  36#define X_AXIS_MAX      1023
  37#define Y_AXIS_MAX      X_AXIS_MAX
  38#define Y_AXIS_MIN      X_AXIS_MIN
  39#define PRESSURE_MAX    X_AXIS_MAX
  40#define PRESSURE_MIN    X_AXIS_MIN
  41
  42static void pcap_ts_read_xy(void *data, u16 res[2])
  43{
  44        struct pcap_ts *pcap_ts = data;
  45
  46        switch (pcap_ts->read_state) {
  47        case PCAP_ADC_TS_M_PRESSURE:
  48                /* pressure reading is unreliable */
  49                if (res[0] > PRESSURE_MIN && res[0] < PRESSURE_MAX)
  50                        pcap_ts->pressure = res[0];
  51                pcap_ts->read_state = PCAP_ADC_TS_M_XY;
  52                schedule_delayed_work(&pcap_ts->work, 0);
  53                break;
  54        case PCAP_ADC_TS_M_XY:
  55                pcap_ts->y = res[0];
  56                pcap_ts->x = res[1];
  57                if (pcap_ts->x <= X_AXIS_MIN || pcap_ts->x >= X_AXIS_MAX ||
  58                    pcap_ts->y <= Y_AXIS_MIN || pcap_ts->y >= Y_AXIS_MAX) {
  59                        /* pen has been released */
  60                        input_report_abs(pcap_ts->input, ABS_PRESSURE, 0);
  61                        input_report_key(pcap_ts->input, BTN_TOUCH, 0);
  62
  63                        pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
  64                        schedule_delayed_work(&pcap_ts->work, 0);
  65                } else {
  66                        /* pen is touching the screen */
  67                        input_report_abs(pcap_ts->input, ABS_X, pcap_ts->x);
  68                        input_report_abs(pcap_ts->input, ABS_Y, pcap_ts->y);
  69                        input_report_key(pcap_ts->input, BTN_TOUCH, 1);
  70                        input_report_abs(pcap_ts->input, ABS_PRESSURE,
  71                                                pcap_ts->pressure);
  72
  73                        /* switch back to pressure read mode */
  74                        pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
  75                        schedule_delayed_work(&pcap_ts->work,
  76                                        msecs_to_jiffies(SAMPLE_DELAY));
  77                }
  78                input_sync(pcap_ts->input);
  79                break;
  80        default:
  81                dev_warn(&pcap_ts->input->dev,
  82                                "pcap_ts: Warning, unhandled read_state %d\n",
  83                                pcap_ts->read_state);
  84                break;
  85        }
  86}
  87
  88static void pcap_ts_work(struct work_struct *work)
  89{
  90        struct delayed_work *dw = to_delayed_work(work);
  91        struct pcap_ts *pcap_ts = container_of(dw, struct pcap_ts, work);
  92        u8 ch[2];
  93
  94        pcap_set_ts_bits(pcap_ts->pcap,
  95                        pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
  96
  97        if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY)
  98                return;
  99
 100        /* start adc conversion */
 101        ch[0] = PCAP_ADC_CH_TS_X1;
 102        ch[1] = PCAP_ADC_CH_TS_Y1;
 103        pcap_adc_async(pcap_ts->pcap, PCAP_ADC_BANK_1, 0, ch,
 104                                                pcap_ts_read_xy, pcap_ts);
 105}
 106
 107static irqreturn_t pcap_ts_event_touch(int pirq, void *data)
 108{
 109        struct pcap_ts *pcap_ts = data;
 110
 111        if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY) {
 112                pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
 113                schedule_delayed_work(&pcap_ts->work, 0);
 114        }
 115        return IRQ_HANDLED;
 116}
 117
 118static int pcap_ts_open(struct input_dev *dev)
 119{
 120        struct pcap_ts *pcap_ts = input_get_drvdata(dev);
 121
 122        pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
 123        schedule_delayed_work(&pcap_ts->work, 0);
 124
 125        return 0;
 126}
 127
 128static void pcap_ts_close(struct input_dev *dev)
 129{
 130        struct pcap_ts *pcap_ts = input_get_drvdata(dev);
 131
 132        cancel_delayed_work_sync(&pcap_ts->work);
 133
 134        pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
 135        pcap_set_ts_bits(pcap_ts->pcap,
 136                                pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
 137}
 138
 139static int pcap_ts_probe(struct platform_device *pdev)
 140{
 141        struct input_dev *input_dev;
 142        struct pcap_ts *pcap_ts;
 143        int err = -ENOMEM;
 144
 145        pcap_ts = kzalloc(sizeof(*pcap_ts), GFP_KERNEL);
 146        if (!pcap_ts)
 147                return err;
 148
 149        pcap_ts->pcap = dev_get_drvdata(pdev->dev.parent);
 150        platform_set_drvdata(pdev, pcap_ts);
 151
 152        input_dev = input_allocate_device();
 153        if (!input_dev)
 154                goto fail;
 155
 156        INIT_DELAYED_WORK(&pcap_ts->work, pcap_ts_work);
 157
 158        pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
 159        pcap_set_ts_bits(pcap_ts->pcap,
 160                                pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
 161
 162        pcap_ts->input = input_dev;
 163        input_set_drvdata(input_dev, pcap_ts);
 164
 165        input_dev->name = "pcap-touchscreen";
 166        input_dev->phys = "pcap_ts/input0";
 167        input_dev->id.bustype = BUS_HOST;
 168        input_dev->id.vendor = 0x0001;
 169        input_dev->id.product = 0x0002;
 170        input_dev->id.version = 0x0100;
 171        input_dev->dev.parent = &pdev->dev;
 172        input_dev->open = pcap_ts_open;
 173        input_dev->close = pcap_ts_close;
 174
 175        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 176        input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 177        input_set_abs_params(input_dev, ABS_X, X_AXIS_MIN, X_AXIS_MAX, 0, 0);
 178        input_set_abs_params(input_dev, ABS_Y, Y_AXIS_MIN, Y_AXIS_MAX, 0, 0);
 179        input_set_abs_params(input_dev, ABS_PRESSURE, PRESSURE_MIN,
 180                             PRESSURE_MAX, 0, 0);
 181
 182        err = input_register_device(pcap_ts->input);
 183        if (err)
 184                goto fail_allocate;
 185
 186        err = request_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS),
 187                        pcap_ts_event_touch, 0, "Touch Screen", pcap_ts);
 188        if (err)
 189                goto fail_register;
 190
 191        return 0;
 192
 193fail_register:
 194        input_unregister_device(input_dev);
 195        goto fail;
 196fail_allocate:
 197        input_free_device(input_dev);
 198fail:
 199        kfree(pcap_ts);
 200
 201        return err;
 202}
 203
 204static int pcap_ts_remove(struct platform_device *pdev)
 205{
 206        struct pcap_ts *pcap_ts = platform_get_drvdata(pdev);
 207
 208        free_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS), pcap_ts);
 209        cancel_delayed_work_sync(&pcap_ts->work);
 210
 211        input_unregister_device(pcap_ts->input);
 212
 213        kfree(pcap_ts);
 214
 215        return 0;
 216}
 217
 218#ifdef CONFIG_PM
 219static int pcap_ts_suspend(struct device *dev)
 220{
 221        struct pcap_ts *pcap_ts = dev_get_drvdata(dev);
 222
 223        pcap_set_ts_bits(pcap_ts->pcap, PCAP_ADC_TS_REF_LOWPWR);
 224        return 0;
 225}
 226
 227static int pcap_ts_resume(struct device *dev)
 228{
 229        struct pcap_ts *pcap_ts = dev_get_drvdata(dev);
 230
 231        pcap_set_ts_bits(pcap_ts->pcap,
 232                                pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
 233        return 0;
 234}
 235
 236static const struct dev_pm_ops pcap_ts_pm_ops = {
 237        .suspend        = pcap_ts_suspend,
 238        .resume         = pcap_ts_resume,
 239};
 240#define PCAP_TS_PM_OPS (&pcap_ts_pm_ops)
 241#else
 242#define PCAP_TS_PM_OPS NULL
 243#endif
 244
 245static struct platform_driver pcap_ts_driver = {
 246        .probe          = pcap_ts_probe,
 247        .remove         = pcap_ts_remove,
 248        .driver         = {
 249                .name   = "pcap-ts",
 250                .pm     = PCAP_TS_PM_OPS,
 251        },
 252};
 253module_platform_driver(pcap_ts_driver);
 254
 255MODULE_DESCRIPTION("Motorola PCAP2 touchscreen driver");
 256MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
 257MODULE_LICENSE("GPL");
 258MODULE_ALIAS("platform:pcap_ts");
 259