drivers/input/touchscreen/pcap_ts.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for Motorola PCAP2 touchscreen as found in the EZX phone platform.
   4  *
   5  *  Copyright (C) 2006 Harald Welte <laforge@openezx.org>
   6  *  Copyright (C) 2009 Daniel Ribeiro <drwyrm@gmail.com>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/fs.h>
  11 #include <linux/string.h>
  12 #include <linux/slab.h>
  13 #include <linux/pm.h>
  14 #include <linux/timer.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/input.h>
  18 #include <linux/mfd/ezx-pcap.h>
  19
  20 struct pcap_ts {
  21         struct pcap_chip *pcap;
  22         struct input_dev *input;
  23         struct delayed_work work;
  24         u16 x, y;
  25         u16 pressure;
  26         u8 read_state;
  27 };
  28
  29 #define SAMPLE_DELAY    20 /* msecs */
  30
  31 #define X_AXIS_MIN      0
  32 #define X_AXIS_MAX      1023
  33 #define Y_AXIS_MAX      X_AXIS_MAX
  34 #define Y_AXIS_MIN      X_AXIS_MIN
  35 #define PRESSURE_MAX    X_AXIS_MAX
  36 #define PRESSURE_MIN    X_AXIS_MIN
  37
  38 static void pcap_ts_read_xy(void *data, u16 res[2])
  39 {
  40         struct pcap_ts *pcap_ts = data;
  41
  42         switch (pcap_ts->read_state) {
  43         case PCAP_ADC_TS_M_PRESSURE:
  44                 /* pressure reading is unreliable */
  45                 if (res[0] > PRESSURE_MIN && res[0] < PRESSURE_MAX)
  46                         pcap_ts->pressure = res[0];
  47                 pcap_ts->read_state = PCAP_ADC_TS_M_XY;
  48                 schedule_delayed_work(&pcap_ts->work, 0);
  49                 break;
  50         case PCAP_ADC_TS_M_XY:
  51                 pcap_ts->y = res[0];
  52                 pcap_ts->x = res[1];
  53                 if (pcap_ts->x <= X_AXIS_MIN || pcap_ts->x >= X_AXIS_MAX ||
  54                     pcap_ts->y <= Y_AXIS_MIN || pcap_ts->y >= Y_AXIS_MAX) {
  55                         /* pen has been released */
  56                         input_report_abs(pcap_ts->input, ABS_PRESSURE, 0);
  57                         input_report_key(pcap_ts->input, BTN_TOUCH, 0);
  58
  59                         pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
  60                         schedule_delayed_work(&pcap_ts->work, 0);
  61                 } else {
  62                         /* pen is touching the screen */
  63                         input_report_abs(pcap_ts->input, ABS_X, pcap_ts->x);
  64                         input_report_abs(pcap_ts->input, ABS_Y, pcap_ts->y);
  65                         input_report_key(pcap_ts->input, BTN_TOUCH, 1);
  66                         input_report_abs(pcap_ts->input, ABS_PRESSURE,
  67                                                 pcap_ts->pressure);
  68
  69                         /* switch back to pressure read mode */
  70                         pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
  71                         schedule_delayed_work(&pcap_ts->work,
  72                                         msecs_to_jiffies(SAMPLE_DELAY));
  73                 }
  74                 input_sync(pcap_ts->input);
  75                 break;
  76         default:
  77                 dev_warn(&pcap_ts->input->dev,
  78                                 "pcap_ts: Warning, unhandled read_state %d\n",
  79                                 pcap_ts->read_state);
  80                 break;
  81         }
  82 }
  83
  84 static void pcap_ts_work(struct work_struct *work)
  85 {
  86         struct delayed_work *dw = to_delayed_work(work);
  87         struct pcap_ts *pcap_ts = container_of(dw, struct pcap_ts, work);
  88         u8 ch[2];
  89
  90         pcap_set_ts_bits(pcap_ts->pcap,
  91                         pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
  92
  93         if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY)
  94                 return;
  95
  96         /* start adc conversion */
  97         ch[0] = PCAP_ADC_CH_TS_X1;
  98         ch[1] = PCAP_ADC_CH_TS_Y1;
  99         pcap_adc_async(pcap_ts->pcap, PCAP_ADC_BANK_1, 0, ch,
 100                                                 pcap_ts_read_xy, pcap_ts);
 101 }
 102
 103 static irqreturn_t pcap_ts_event_touch(int pirq, void *data)
 104 {
 105         struct pcap_ts *pcap_ts = data;
 106
 107         if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY) {
 108                 pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
 109                 schedule_delayed_work(&pcap_ts->work, 0);
 110         }
 111         return IRQ_HANDLED;
 112 }
 113
 114 static int pcap_ts_open(struct input_dev *dev)
 115 {
 116         struct pcap_ts *pcap_ts = input_get_drvdata(dev);
 117
 118         pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
 119         schedule_delayed_work(&pcap_ts->work, 0);
 120
 121         return 0;
 122 }
 123
 124 static void pcap_ts_close(struct input_dev *dev)
 125 {
 126         struct pcap_ts *pcap_ts = input_get_drvdata(dev);
 127
 128         cancel_delayed_work_sync(&pcap_ts->work);
 129
 130         pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
 131         pcap_set_ts_bits(pcap_ts->pcap,
 132                                 pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
 133 }
 134
 135 static int pcap_ts_probe(struct platform_device *pdev)
 136 {
 137         struct input_dev *input_dev;
 138         struct pcap_ts *pcap_ts;
 139         int err = -ENOMEM;
 140
 141         pcap_ts = kzalloc(sizeof(*pcap_ts), GFP_KERNEL);
 142         if (!pcap_ts)
 143                 return err;
 144
 145         pcap_ts->pcap = dev_get_drvdata(pdev->dev.parent);
 146         platform_set_drvdata(pdev, pcap_ts);
 147
 148         input_dev = input_allocate_device();
 149         if (!input_dev)
 150                 goto fail;
 151
 152         INIT_DELAYED_WORK(&pcap_ts->work, pcap_ts_work);
 153
 154         pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
 155         pcap_set_ts_bits(pcap_ts->pcap,
 156                                 pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
 157
 158         pcap_ts->input = input_dev;
 159         input_set_drvdata(input_dev, pcap_ts);
 160
 161         input_dev->name = "pcap-touchscreen";
 162         input_dev->phys = "pcap_ts/input0";
 163         input_dev->id.bustype = BUS_HOST;
 164         input_dev->id.vendor = 0x0001;
 165         input_dev->id.product = 0x0002;
 166         input_dev->id.version = 0x0100;
 167         input_dev->dev.parent = &pdev->dev;
 168         input_dev->open = pcap_ts_open;
 169         input_dev->close = pcap_ts_close;
 170
 171         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 172         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 173         input_set_abs_params(input_dev, ABS_X, X_AXIS_MIN, X_AXIS_MAX, 0, 0);
 174         input_set_abs_params(input_dev, ABS_Y, Y_AXIS_MIN, Y_AXIS_MAX, 0, 0);
 175         input_set_abs_params(input_dev, ABS_PRESSURE, PRESSURE_MIN,
 176                              PRESSURE_MAX, 0, 0);
 177
 178         err = input_register_device(pcap_ts->input);
 179         if (err)
 180                 goto fail_allocate;
 181
 182         err = request_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS),
 183                         pcap_ts_event_touch, 0, "Touch Screen", pcap_ts);
 184         if (err)
 185                 goto fail_register;
 186
 187         return 0;
 188
 189 fail_register:
 190         input_unregister_device(input_dev);
 191         goto fail;
 192 fail_allocate:
 193         input_free_device(input_dev);
 194 fail:
 195         kfree(pcap_ts);
 196
 197         return err;
 198 }
 199
 200 static void pcap_ts_remove(struct platform_device *pdev)
 201 {
 202         struct pcap_ts *pcap_ts = platform_get_drvdata(pdev);
 203
 204         free_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS), pcap_ts);
 205         cancel_delayed_work_sync(&pcap_ts->work);
 206
 207         input_unregister_device(pcap_ts->input);
 208
 209         kfree(pcap_ts);
 210 }
 211
 212 #ifdef CONFIG_PM
 213 static int pcap_ts_suspend(struct device *dev)
 214 {
 215         struct pcap_ts *pcap_ts = dev_get_drvdata(dev);
 216
 217         pcap_set_ts_bits(pcap_ts->pcap, PCAP_ADC_TS_REF_LOWPWR);
 218         return 0;
 219 }
 220
 221 static int pcap_ts_resume(struct device *dev)
 222 {
 223         struct pcap_ts *pcap_ts = dev_get_drvdata(dev);
 224
 225         pcap_set_ts_bits(pcap_ts->pcap,
 226                                 pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
 227         return 0;
 228 }
 229
 230 static const struct dev_pm_ops pcap_ts_pm_ops = {
 231         .suspend        = pcap_ts_suspend,
 232         .resume         = pcap_ts_resume,
 233 };
 234 #define PCAP_TS_PM_OPS (&pcap_ts_pm_ops)
 235 #else
 236 #define PCAP_TS_PM_OPS NULL
 237 #endif
 238
 239 static struct platform_driver pcap_ts_driver = {
 240         .probe          = pcap_ts_probe,
 241         .remove_new     = pcap_ts_remove,
 242         .driver         = {
 243                 .name   = "pcap-ts",
 244                 .pm     = PCAP_TS_PM_OPS,
 245         },
 246 };
 247 module_platform_driver(pcap_ts_driver);
 248
 249 MODULE_DESCRIPTION("Motorola PCAP2 touchscreen driver");
 250 MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
 251 MODULE_LICENSE("GPL");
 252 MODULE_ALIAS("platform:pcap_ts");