drivers/input/touchscreen/pcap_ts.c

   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
  24 struct 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
  42 static 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
  88 static void pcap_ts_work(struct work_struct *work)
  89 {
  90         struct delayed_work *dw = container_of(work, struct 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
 107 static 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
 118 static 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
 128 static 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
 139 static 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
 193 fail_register:
 194         input_unregister_device(input_dev);
 195         goto fail;
 196 fail_allocate:
 197         input_free_device(input_dev);
 198 fail:
 199         kfree(pcap_ts);
 200
 201         return err;
 202 }
 203
 204 static 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
 219 static 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
 227 static 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
 236 static 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
 245 static struct platform_driver pcap_ts_driver = {
 246         .probe          = pcap_ts_probe,
 247         .remove         = pcap_ts_remove,
 248         .driver         = {
 249                 .name   = "pcap-ts",
 250                 .owner  = THIS_MODULE,
 251                 .pm     = PCAP_TS_PM_OPS,
 252         },
 253 };
 254 module_platform_driver(pcap_ts_driver);
 255
 256 MODULE_DESCRIPTION("Motorola PCAP2 touchscreen driver");
 257 MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
 258 MODULE_LICENSE("GPL");
 259 MODULE_ALIAS("platform:pcap_ts");