drivers/input/touchscreen/mc13783_ts.c

   1 /*
   2  * Driver for the Freescale Semiconductor MC13783 touchscreen.
   3  *
   4  * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
   5  * Copyright (C) 2009 Sascha Hauer, Pengutronix
   6  *
   7  * Initial development of this code was funded by
   8  * Phytec Messtechnik GmbH, http://www.phytec.de/
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License version 2 as published by
  12  * the Free Software Foundation.
  13  */
  14 #include <linux/platform_device.h>
  15 #include <linux/mfd/mc13783.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/input.h>
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/init.h>
  22
  23 #define MC13783_TS_NAME "mc13783-ts"
  24
  25 #define DEFAULT_SAMPLE_TOLERANCE 300
  26
  27 static unsigned int sample_tolerance = DEFAULT_SAMPLE_TOLERANCE;
  28 module_param(sample_tolerance, uint, S_IRUGO | S_IWUSR);
  29 MODULE_PARM_DESC(sample_tolerance,
  30                 "If the minimal and maximal value read out for one axis (out "
  31                 "of three) differ by this value (default: "
  32                 __stringify(DEFAULT_SAMPLE_TOLERANCE) ") or more, the reading "
  33                 "is supposed to be wrong and is discarded.  Set to 0 to "
  34                 "disable this check.");
  35
  36 struct mc13783_ts_priv {
  37         struct input_dev *idev;
  38         struct mc13783 *mc13783;
  39         struct delayed_work work;
  40         struct workqueue_struct *workq;
  41         unsigned int sample[4];
  42 };
  43
  44 static irqreturn_t mc13783_ts_handler(int irq, void *data)
  45 {
  46         struct mc13783_ts_priv *priv = data;
  47
  48         mc13783_irq_ack(priv->mc13783, irq);
  49
  50         /*
  51          * Kick off reading coordinates. Note that if work happens already
  52          * be queued for future execution (it rearms itself) it will not
  53          * be rescheduled for immediate execution here. However the rearm
  54          * delay is HZ / 50 which is acceptable.
  55          */
  56         queue_delayed_work(priv->workq, &priv->work, 0);
  57
  58         return IRQ_HANDLED;
  59 }
  60
  61 #define sort3(a0, a1, a2) ({                                            \
  62                 if (a0 > a1)                                            \
  63                         swap(a0, a1);                                   \
  64                 if (a1 > a2)                                            \
  65                         swap(a1, a2);                                   \
  66                 if (a0 > a1)                                            \
  67                         swap(a0, a1);                                   \
  68                 })
  69
  70 static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
  71 {
  72         struct input_dev *idev = priv->idev;
  73         int x0, x1, x2, y0, y1, y2;
  74         int cr0, cr1;
  75
  76         /*
  77          * the values are 10-bit wide only, but the two least significant
  78          * bits are for future 12 bit use and reading yields 0
  79          */
  80         x0 = priv->sample[0] & 0xfff;
  81         x1 = priv->sample[1] & 0xfff;
  82         x2 = priv->sample[2] & 0xfff;
  83         y0 = priv->sample[3] & 0xfff;
  84         y1 = (priv->sample[0] >> 12) & 0xfff;
  85         y2 = (priv->sample[1] >> 12) & 0xfff;
  86         cr0 = (priv->sample[2] >> 12) & 0xfff;
  87         cr1 = (priv->sample[3] >> 12) & 0xfff;
  88
  89         dev_dbg(&idev->dev,
  90                 "x: (% 4d,% 4d,% 4d) y: (% 4d, % 4d,% 4d) cr: (% 4d, % 4d)\n",
  91                 x0, x1, x2, y0, y1, y2, cr0, cr1);
  92
  93         sort3(x0, x1, x2);
  94         sort3(y0, y1, y2);
  95
  96         cr0 = (cr0 + cr1) / 2;
  97
  98         if (!cr0 || !sample_tolerance ||
  99                         (x2 - x0 < sample_tolerance &&
 100                          y2 - y0 < sample_tolerance)) {
 101                 /* report the median coordinate and average pressure */
 102                 if (cr0) {
 103                         input_report_abs(idev, ABS_X, x1);
 104                         input_report_abs(idev, ABS_Y, y1);
 105
 106                         dev_dbg(&idev->dev, "report (%d, %d, %d)\n",
 107                                         x1, y1, 0x1000 - cr0);
 108                         queue_delayed_work(priv->workq, &priv->work, HZ / 50);
 109                 } else
 110                         dev_dbg(&idev->dev, "report release\n");
 111
 112                 input_report_abs(idev, ABS_PRESSURE,
 113                                 cr0 ? 0x1000 - cr0 : cr0);
 114                 input_report_key(idev, BTN_TOUCH, cr0);
 115                 input_sync(idev);
 116         } else
 117                 dev_dbg(&idev->dev, "discard event\n");
 118 }
 119
 120 static void mc13783_ts_work(struct work_struct *work)
 121 {
 122         struct mc13783_ts_priv *priv =
 123                 container_of(work, struct mc13783_ts_priv, work.work);
 124         unsigned int mode = MC13783_ADC_MODE_TS;
 125         unsigned int channel = 12;
 126
 127         if (mc13783_adc_do_conversion(priv->mc13783,
 128                                 mode, channel, priv->sample) == 0)
 129                 mc13783_ts_report_sample(priv);
 130 }
 131
 132 static int mc13783_ts_open(struct input_dev *dev)
 133 {
 134         struct mc13783_ts_priv *priv = input_get_drvdata(dev);
 135         int ret;
 136
 137         mc13783_lock(priv->mc13783);
 138
 139         mc13783_irq_ack(priv->mc13783, MC13783_IRQ_TS);
 140
 141         ret = mc13783_irq_request(priv->mc13783, MC13783_IRQ_TS,
 142                 mc13783_ts_handler, MC13783_TS_NAME, priv);
 143         if (ret)
 144                 goto out;
 145
 146         ret = mc13783_reg_rmw(priv->mc13783, MC13783_ADC0,
 147                         MC13783_ADC0_TSMOD_MASK, MC13783_ADC0_TSMOD0);
 148         if (ret)
 149                 mc13783_irq_free(priv->mc13783, MC13783_IRQ_TS, priv);
 150 out:
 151         mc13783_unlock(priv->mc13783);
 152         return ret;
 153 }
 154
 155 static void mc13783_ts_close(struct input_dev *dev)
 156 {
 157         struct mc13783_ts_priv *priv = input_get_drvdata(dev);
 158
 159         mc13783_lock(priv->mc13783);
 160         mc13783_reg_rmw(priv->mc13783, MC13783_ADC0,
 161                         MC13783_ADC0_TSMOD_MASK, 0);
 162         mc13783_irq_free(priv->mc13783, MC13783_IRQ_TS, priv);
 163         mc13783_unlock(priv->mc13783);
 164
 165         cancel_delayed_work_sync(&priv->work);
 166 }
 167
 168 static int __init mc13783_ts_probe(struct platform_device *pdev)
 169 {
 170         struct mc13783_ts_priv *priv;
 171         struct input_dev *idev;
 172         int ret = -ENOMEM;
 173
 174         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 175         idev = input_allocate_device();
 176         if (!priv || !idev)
 177                 goto err_free_mem;
 178
 179         INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
 180         priv->mc13783 = dev_get_drvdata(pdev->dev.parent);
 181         priv->idev = idev;
 182
 183         /*
 184          * We need separate workqueue because mc13783_adc_do_conversion
 185          * uses keventd and thus would deadlock.
 186          */
 187         priv->workq = create_singlethread_workqueue("mc13783_ts");
 188         if (!priv->workq)
 189                 goto err_free_mem;
 190
 191         idev->name = MC13783_TS_NAME;
 192         idev->dev.parent = &pdev->dev;
 193
 194         idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 195         idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 196         input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
 197         input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
 198         input_set_abs_params(idev, ABS_PRESSURE, 0, 0xfff, 0, 0);
 199
 200         idev->open = mc13783_ts_open;
 201         idev->close = mc13783_ts_close;
 202
 203         input_set_drvdata(idev, priv);
 204
 205         ret = input_register_device(priv->idev);
 206         if (ret) {
 207                 dev_err(&pdev->dev,
 208                         "register input device failed with %d\n", ret);
 209                 goto err_destroy_wq;
 210         }
 211
 212         platform_set_drvdata(pdev, priv);
 213         return 0;
 214
 215 err_destroy_wq:
 216         destroy_workqueue(priv->workq);
 217 err_free_mem:
 218         input_free_device(idev);
 219         kfree(priv);
 220         return ret;
 221 }
 222
 223 static int __devexit mc13783_ts_remove(struct platform_device *pdev)
 224 {
 225         struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);
 226
 227         platform_set_drvdata(pdev, NULL);
 228
 229         destroy_workqueue(priv->workq);
 230         input_unregister_device(priv->idev);
 231         kfree(priv);
 232
 233         return 0;
 234 }
 235
 236 static struct platform_driver mc13783_ts_driver = {
 237         .remove         = __devexit_p(mc13783_ts_remove),
 238         .driver         = {
 239                 .owner  = THIS_MODULE,
 240                 .name   = MC13783_TS_NAME,
 241         },
 242 };
 243
 244 static int __init mc13783_ts_init(void)
 245 {
 246         return platform_driver_probe(&mc13783_ts_driver, &mc13783_ts_probe);
 247 }
 248 module_init(mc13783_ts_init);
 249
 250 static void __exit mc13783_ts_exit(void)
 251 {
 252         platform_driver_unregister(&mc13783_ts_driver);
 253 }
 254 module_exit(mc13783_ts_exit);
 255
 256 MODULE_DESCRIPTION("MC13783 input touchscreen driver");
 257 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
 258 MODULE_LICENSE("GPL v2");
 259 MODULE_ALIAS("platform:" MC13783_TS_NAME);