drivers/input/touchscreen/mc13783_ts.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for the Freescale Semiconductor MC13783 touchscreen.
   4  *
   5  * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
   6  * Copyright (C) 2009 Sascha Hauer, Pengutronix
   7  *
   8  * Initial development of this code was funded by
   9  * Phytec Messtechnik GmbH, http://www.phytec.de/
  10  */
  11 #include <linux/platform_device.h>
  12 #include <linux/mfd/mc13783.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/input.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/init.h>
  19
  20 #define MC13783_TS_NAME "mc13783-ts"
  21
  22 #define DEFAULT_SAMPLE_TOLERANCE 300
  23
  24 static unsigned int sample_tolerance = DEFAULT_SAMPLE_TOLERANCE;
  25 module_param(sample_tolerance, uint, S_IRUGO | S_IWUSR);
  26 MODULE_PARM_DESC(sample_tolerance,
  27                 "If the minimal and maximal value read out for one axis (out "
  28                 "of three) differ by this value (default: "
  29                 __stringify(DEFAULT_SAMPLE_TOLERANCE) ") or more, the reading "
  30                 "is supposed to be wrong and is discarded.  Set to 0 to "
  31                 "disable this check.");
  32
  33 struct mc13783_ts_priv {
  34         struct input_dev *idev;
  35         struct mc13xxx *mc13xxx;
  36         struct delayed_work work;
  37         unsigned int sample[4];
  38         struct mc13xxx_ts_platform_data *touch;
  39 };
  40
  41 static irqreturn_t mc13783_ts_handler(int irq, void *data)
  42 {
  43         struct mc13783_ts_priv *priv = data;
  44
  45         mc13xxx_irq_ack(priv->mc13xxx, irq);
  46
  47         /*
  48          * Kick off reading coordinates. Note that if work happens already
  49          * be queued for future execution (it rearms itself) it will not
  50          * be rescheduled for immediate execution here. However the rearm
  51          * delay is HZ / 50 which is acceptable.
  52          */
  53         schedule_delayed_work(&priv->work, 0);
  54
  55         return IRQ_HANDLED;
  56 }
  57
  58 #define sort3(a0, a1, a2) ({                                            \
  59                 if (a0 > a1)                                            \
  60                         swap(a0, a1);                                   \
  61                 if (a1 > a2)                                            \
  62                         swap(a1, a2);                                   \
  63                 if (a0 > a1)                                            \
  64                         swap(a0, a1);                                   \
  65                 })
  66
  67 static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
  68 {
  69         struct input_dev *idev = priv->idev;
  70         int x0, x1, x2, y0, y1, y2;
  71         int cr0, cr1;
  72
  73         /*
  74          * the values are 10-bit wide only, but the two least significant
  75          * bits are for future 12 bit use and reading yields 0
  76          */
  77         x0 = priv->sample[0] & 0xfff;
  78         x1 = priv->sample[1] & 0xfff;
  79         x2 = priv->sample[2] & 0xfff;
  80         y0 = priv->sample[3] & 0xfff;
  81         y1 = (priv->sample[0] >> 12) & 0xfff;
  82         y2 = (priv->sample[1] >> 12) & 0xfff;
  83         cr0 = (priv->sample[2] >> 12) & 0xfff;
  84         cr1 = (priv->sample[3] >> 12) & 0xfff;
  85
  86         dev_dbg(&idev->dev,
  87                 "x: (% 4d,% 4d,% 4d) y: (% 4d, % 4d,% 4d) cr: (% 4d, % 4d)\n",
  88                 x0, x1, x2, y0, y1, y2, cr0, cr1);
  89
  90         sort3(x0, x1, x2);
  91         sort3(y0, y1, y2);
  92
  93         cr0 = (cr0 + cr1) / 2;
  94
  95         if (!cr0 || !sample_tolerance ||
  96                         (x2 - x0 < sample_tolerance &&
  97                          y2 - y0 < sample_tolerance)) {
  98                 /* report the median coordinate and average pressure */
  99                 if (cr0) {
 100                         input_report_abs(idev, ABS_X, x1);
 101                         input_report_abs(idev, ABS_Y, y1);
 102
 103                         dev_dbg(&idev->dev, "report (%d, %d, %d)\n",
 104                                         x1, y1, 0x1000 - cr0);
 105                         schedule_delayed_work(&priv->work, HZ / 50);
 106                 } else {
 107                         dev_dbg(&idev->dev, "report release\n");
 108                 }
 109
 110                 input_report_abs(idev, ABS_PRESSURE,
 111                                 cr0 ? 0x1000 - cr0 : cr0);
 112                 input_report_key(idev, BTN_TOUCH, cr0);
 113                 input_sync(idev);
 114         } else {
 115                 dev_dbg(&idev->dev, "discard event\n");
 116         }
 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 = MC13XXX_ADC_MODE_TS;
 124         unsigned int channel = 12;
 125
 126         if (mc13xxx_adc_do_conversion(priv->mc13xxx,
 127                                 mode, channel,
 128                                 priv->touch->ato, priv->touch->atox,
 129                                 priv->sample) == 0)
 130                 mc13783_ts_report_sample(priv);
 131 }
 132
 133 static int mc13783_ts_open(struct input_dev *dev)
 134 {
 135         struct mc13783_ts_priv *priv = input_get_drvdata(dev);
 136         int ret;
 137
 138         mc13xxx_lock(priv->mc13xxx);
 139
 140         mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TS);
 141
 142         ret = mc13xxx_irq_request(priv->mc13xxx, MC13XXX_IRQ_TS,
 143                 mc13783_ts_handler, MC13783_TS_NAME, priv);
 144         if (ret)
 145                 goto out;
 146
 147         ret = mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
 148                         MC13XXX_ADC0_TSMOD_MASK, MC13XXX_ADC0_TSMOD0);
 149         if (ret)
 150                 mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
 151 out:
 152         mc13xxx_unlock(priv->mc13xxx);
 153         return ret;
 154 }
 155
 156 static void mc13783_ts_close(struct input_dev *dev)
 157 {
 158         struct mc13783_ts_priv *priv = input_get_drvdata(dev);
 159
 160         mc13xxx_lock(priv->mc13xxx);
 161         mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
 162                         MC13XXX_ADC0_TSMOD_MASK, 0);
 163         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
 164         mc13xxx_unlock(priv->mc13xxx);
 165
 166         cancel_delayed_work_sync(&priv->work);
 167 }
 168
 169 static int __init mc13783_ts_probe(struct platform_device *pdev)
 170 {
 171         struct mc13783_ts_priv *priv;
 172         struct input_dev *idev;
 173         int ret = -ENOMEM;
 174
 175         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 176         idev = input_allocate_device();
 177         if (!priv || !idev)
 178                 goto err_free_mem;
 179
 180         INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
 181         priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
 182         priv->idev = idev;
 183         priv->touch = dev_get_platdata(&pdev->dev);
 184         if (!priv->touch) {
 185                 dev_err(&pdev->dev, "missing platform data\n");
 186                 ret = -ENODEV;
 187                 goto err_free_mem;
 188         }
 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_free_mem;
 209         }
 210
 211         platform_set_drvdata(pdev, priv);
 212         return 0;
 213
 214 err_free_mem:
 215         input_free_device(idev);
 216         kfree(priv);
 217         return ret;
 218 }
 219
 220 static void mc13783_ts_remove(struct platform_device *pdev)
 221 {
 222         struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);
 223
 224         input_unregister_device(priv->idev);
 225         kfree(priv);
 226 }
 227
 228 static struct platform_driver mc13783_ts_driver = {
 229         .remove         = mc13783_ts_remove,
 230         .driver         = {
 231                 .name   = MC13783_TS_NAME,
 232         },
 233 };
 234
 235 module_platform_driver_probe(mc13783_ts_driver, mc13783_ts_probe);
 236
 237 MODULE_DESCRIPTION("MC13783 input touchscreen driver");
 238 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
 239 MODULE_LICENSE("GPL v2");
 240 MODULE_ALIAS("platform:" MC13783_TS_NAME);