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