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         unsigned int sample[4];
  41         struct mc13xxx_ts_platform_data *touch;
  42 };
  43
  44 static irqreturn_t mc13783_ts_handler(int irq, void *data)
  45 {
  46         struct mc13783_ts_priv *priv = data;
  47
  48         mc13xxx_irq_ack(priv->mc13xxx, 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         schedule_delayed_work(&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                         schedule_delayed_work(&priv->work, HZ / 50);
 109                 } else {
 110                         dev_dbg(&idev->dev, "report release\n");
 111                 }
 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
 122 static void mc13783_ts_work(struct work_struct *work)
 123 {
 124         struct mc13783_ts_priv *priv =
 125                 container_of(work, struct mc13783_ts_priv, work.work);
 126         unsigned int mode = MC13XXX_ADC_MODE_TS;
 127         unsigned int channel = 12;
 128
 129         if (mc13xxx_adc_do_conversion(priv->mc13xxx,
 130                                 mode, channel,
 131                                 priv->touch->ato, priv->touch->atox,
 132                                 priv->sample) == 0)
 133                 mc13783_ts_report_sample(priv);
 134 }
 135
 136 static int mc13783_ts_open(struct input_dev *dev)
 137 {
 138         struct mc13783_ts_priv *priv = input_get_drvdata(dev);
 139         int ret;
 140
 141         mc13xxx_lock(priv->mc13xxx);
 142
 143         mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TS);
 144
 145         ret = mc13xxx_irq_request(priv->mc13xxx, MC13XXX_IRQ_TS,
 146                 mc13783_ts_handler, MC13783_TS_NAME, priv);
 147         if (ret)
 148                 goto out;
 149
 150         ret = mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
 151                         MC13XXX_ADC0_TSMOD_MASK, MC13XXX_ADC0_TSMOD0);
 152         if (ret)
 153                 mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
 154 out:
 155         mc13xxx_unlock(priv->mc13xxx);
 156         return ret;
 157 }
 158
 159 static void mc13783_ts_close(struct input_dev *dev)
 160 {
 161         struct mc13783_ts_priv *priv = input_get_drvdata(dev);
 162
 163         mc13xxx_lock(priv->mc13xxx);
 164         mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
 165                         MC13XXX_ADC0_TSMOD_MASK, 0);
 166         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
 167         mc13xxx_unlock(priv->mc13xxx);
 168
 169         cancel_delayed_work_sync(&priv->work);
 170 }
 171
 172 static int __init mc13783_ts_probe(struct platform_device *pdev)
 173 {
 174         struct mc13783_ts_priv *priv;
 175         struct input_dev *idev;
 176         int ret = -ENOMEM;
 177
 178         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 179         idev = input_allocate_device();
 180         if (!priv || !idev)
 181                 goto err_free_mem;
 182
 183         INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
 184         priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
 185         priv->idev = idev;
 186         priv->touch = dev_get_platdata(&pdev->dev);
 187         if (!priv->touch) {
 188                 dev_err(&pdev->dev, "missing platform data\n");
 189                 ret = -ENODEV;
 190                 goto err_free_mem;
 191         }
 192
 193         idev->name = MC13783_TS_NAME;
 194         idev->dev.parent = &pdev->dev;
 195
 196         idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 197         idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 198         input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
 199         input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
 200         input_set_abs_params(idev, ABS_PRESSURE, 0, 0xfff, 0, 0);
 201
 202         idev->open = mc13783_ts_open;
 203         idev->close = mc13783_ts_close;
 204
 205         input_set_drvdata(idev, priv);
 206
 207         ret = input_register_device(priv->idev);
 208         if (ret) {
 209                 dev_err(&pdev->dev,
 210                         "register input device failed with %d\n", ret);
 211                 goto err_free_mem;
 212         }
 213
 214         platform_set_drvdata(pdev, priv);
 215         return 0;
 216
 217 err_free_mem:
 218         input_free_device(idev);
 219         kfree(priv);
 220         return ret;
 221 }
 222
 223 static int mc13783_ts_remove(struct platform_device *pdev)
 224 {
 225         struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);
 226
 227         input_unregister_device(priv->idev);
 228         kfree(priv);
 229
 230         return 0;
 231 }
 232
 233 static struct platform_driver mc13783_ts_driver = {
 234         .remove         = mc13783_ts_remove,
 235         .driver         = {
 236                 .name   = MC13783_TS_NAME,
 237         },
 238 };
 239
 240 module_platform_driver_probe(mc13783_ts_driver, mc13783_ts_probe);
 241
 242 MODULE_DESCRIPTION("MC13783 input touchscreen driver");
 243 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
 244 MODULE_LICENSE("GPL v2");
 245 MODULE_ALIAS("platform:" MC13783_TS_NAME);