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 mc13xxx *mc13xxx;
  39         struct delayed_work work;
  40         struct workqueue_struct *workq;
  41         unsigned int sample[4];
  42         struct mc13xxx_ts_platform_data *touch;
  43 };
  44
  45 static irqreturn_t mc13783_ts_handler(int irq, void *data)
  46 {
  47         struct mc13783_ts_priv *priv = data;
  48
  49         mc13xxx_irq_ack(priv->mc13xxx, irq);
  50
  51         /*
  52          * Kick off reading coordinates. Note that if work happens already
  53          * be queued for future execution (it rearms itself) it will not
  54          * be rescheduled for immediate execution here. However the rearm
  55          * delay is HZ / 50 which is acceptable.
  56          */
  57         queue_delayed_work(priv->workq, &priv->work, 0);
  58
  59         return IRQ_HANDLED;
  60 }
  61
  62 #define sort3(a0, a1, a2) ({                                            \
  63                 if (a0 > a1)                                            \
  64                         swap(a0, a1);                                   \
  65                 if (a1 > a2)                                            \
  66                         swap(a1, a2);                                   \
  67                 if (a0 > a1)                                            \
  68                         swap(a0, a1);                                   \
  69                 })
  70
  71 static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
  72 {
  73         struct input_dev *idev = priv->idev;
  74         int x0, x1, x2, y0, y1, y2;
  75         int cr0, cr1;
  76
  77         /*
  78          * the values are 10-bit wide only, but the two least significant
  79          * bits are for future 12 bit use and reading yields 0
  80          */
  81         x0 = priv->sample[0] & 0xfff;
  82         x1 = priv->sample[1] & 0xfff;
  83         x2 = priv->sample[2] & 0xfff;
  84         y0 = priv->sample[3] & 0xfff;
  85         y1 = (priv->sample[0] >> 12) & 0xfff;
  86         y2 = (priv->sample[1] >> 12) & 0xfff;
  87         cr0 = (priv->sample[2] >> 12) & 0xfff;
  88         cr1 = (priv->sample[3] >> 12) & 0xfff;
  89
  90         dev_dbg(&idev->dev,
  91                 "x: (% 4d,% 4d,% 4d) y: (% 4d, % 4d,% 4d) cr: (% 4d, % 4d)\n",
  92                 x0, x1, x2, y0, y1, y2, cr0, cr1);
  93
  94         sort3(x0, x1, x2);
  95         sort3(y0, y1, y2);
  96
  97         cr0 = (cr0 + cr1) / 2;
  98
  99         if (!cr0 || !sample_tolerance ||
 100                         (x2 - x0 < sample_tolerance &&
 101                          y2 - y0 < sample_tolerance)) {
 102                 /* report the median coordinate and average pressure */
 103                 if (cr0) {
 104                         input_report_abs(idev, ABS_X, x1);
 105                         input_report_abs(idev, ABS_Y, y1);
 106
 107                         dev_dbg(&idev->dev, "report (%d, %d, %d)\n",
 108                                         x1, y1, 0x1000 - cr0);
 109                         queue_delayed_work(priv->workq, &priv->work, HZ / 50);
 110                 } else
 111                         dev_dbg(&idev->dev, "report release\n");
 112
 113                 input_report_abs(idev, ABS_PRESSURE,
 114                                 cr0 ? 0x1000 - cr0 : cr0);
 115                 input_report_key(idev, BTN_TOUCH, cr0);
 116                 input_sync(idev);
 117         } else
 118                 dev_dbg(&idev->dev, "discard event\n");
 119 }
 120
 121 static void mc13783_ts_work(struct work_struct *work)
 122 {
 123         struct mc13783_ts_priv *priv =
 124                 container_of(work, struct mc13783_ts_priv, work.work);
 125         unsigned int mode = MC13XXX_ADC_MODE_TS;
 126         unsigned int channel = 12;
 127
 128         if (mc13xxx_adc_do_conversion(priv->mc13xxx,
 129                                 mode, channel,
 130                                 priv->touch->ato, priv->touch->atox,
 131                                 priv->sample) == 0)
 132                 mc13783_ts_report_sample(priv);
 133 }
 134
 135 static int mc13783_ts_open(struct input_dev *dev)
 136 {
 137         struct mc13783_ts_priv *priv = input_get_drvdata(dev);
 138         int ret;
 139
 140         mc13xxx_lock(priv->mc13xxx);
 141
 142         mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TS);
 143
 144         ret = mc13xxx_irq_request(priv->mc13xxx, MC13XXX_IRQ_TS,
 145                 mc13783_ts_handler, MC13783_TS_NAME, priv);
 146         if (ret)
 147                 goto out;
 148
 149         ret = mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
 150                         MC13XXX_ADC0_TSMOD_MASK, MC13XXX_ADC0_TSMOD0);
 151         if (ret)
 152                 mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
 153 out:
 154         mc13xxx_unlock(priv->mc13xxx);
 155         return ret;
 156 }
 157
 158 static void mc13783_ts_close(struct input_dev *dev)
 159 {
 160         struct mc13783_ts_priv *priv = input_get_drvdata(dev);
 161
 162         mc13xxx_lock(priv->mc13xxx);
 163         mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
 164                         MC13XXX_ADC0_TSMOD_MASK, 0);
 165         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
 166         mc13xxx_unlock(priv->mc13xxx);
 167
 168         cancel_delayed_work_sync(&priv->work);
 169 }
 170
 171 static int __init mc13783_ts_probe(struct platform_device *pdev)
 172 {
 173         struct mc13783_ts_priv *priv;
 174         struct input_dev *idev;
 175         int ret = -ENOMEM;
 176
 177         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 178         idev = input_allocate_device();
 179         if (!priv || !idev)
 180                 goto err_free_mem;
 181
 182         INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
 183         priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
 184         priv->idev = idev;
 185         priv->touch = dev_get_platdata(&pdev->dev);
 186         if (!priv->touch) {
 187                 dev_err(&pdev->dev, "missing platform data\n");
 188                 ret = -ENODEV;
 189                 goto err_free_mem;
 190         }
 191
 192         /*
 193          * We need separate workqueue because mc13783_adc_do_conversion
 194          * uses keventd and thus would deadlock.
 195          */
 196         priv->workq = create_singlethread_workqueue("mc13783_ts");
 197         if (!priv->workq)
 198                 goto err_free_mem;
 199
 200         idev->name = MC13783_TS_NAME;
 201         idev->dev.parent = &pdev->dev;
 202
 203         idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 204         idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 205         input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
 206         input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
 207         input_set_abs_params(idev, ABS_PRESSURE, 0, 0xfff, 0, 0);
 208
 209         idev->open = mc13783_ts_open;
 210         idev->close = mc13783_ts_close;
 211
 212         input_set_drvdata(idev, priv);
 213
 214         ret = input_register_device(priv->idev);
 215         if (ret) {
 216                 dev_err(&pdev->dev,
 217                         "register input device failed with %d\n", ret);
 218                 goto err_destroy_wq;
 219         }
 220
 221         platform_set_drvdata(pdev, priv);
 222         return 0;
 223
 224 err_destroy_wq:
 225         destroy_workqueue(priv->workq);
 226 err_free_mem:
 227         input_free_device(idev);
 228         kfree(priv);
 229         return ret;
 230 }
 231
 232 static int mc13783_ts_remove(struct platform_device *pdev)
 233 {
 234         struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);
 235
 236         destroy_workqueue(priv->workq);
 237         input_unregister_device(priv->idev);
 238         kfree(priv);
 239
 240         return 0;
 241 }
 242
 243 static struct platform_driver mc13783_ts_driver = {
 244         .remove         = mc13783_ts_remove,
 245         .driver         = {
 246                 .name   = MC13783_TS_NAME,
 247         },
 248 };
 249
 250 module_platform_driver_probe(mc13783_ts_driver, mc13783_ts_probe);
 251
 252 MODULE_DESCRIPTION("MC13783 input touchscreen driver");
 253 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
 254 MODULE_LICENSE("GPL v2");
 255 MODULE_ALIAS("platform:" MC13783_TS_NAME);