input/touchscreen/mc13783_ts.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Driver for the Freescale Semiconductor MC13783 touchscreen.
0004  *
0005  * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
0006  * Copyright (C) 2009 Sascha Hauer, Pengutronix
0007  *
0008  * Initial development of this code was funded by
0009  * Phytec Messtechnik GmbH, http://www.phytec.de/
0010  */
0011 #include <linux/platform_device.h>
0012 #include <linux/mfd/mc13783.h>
0013 #include <linux/kernel.h>
0014 #include <linux/module.h>
0015 #include <linux/input.h>
0016 #include <linux/sched.h>
0017 #include <linux/slab.h>
0018 #include <linux/init.h>
0019
0020 #define MC13783_TS_NAME "mc13783-ts"
0021
0022 #define DEFAULT_SAMPLE_TOLERANCE 300
0023
0024 static unsigned int sample_tolerance = DEFAULT_SAMPLE_TOLERANCE;
0025 module_param(sample_tolerance, uint, S_IRUGO | S_IWUSR);
0026 MODULE_PARM_DESC(sample_tolerance,
0027         "If the minimal and maximal value read out for one axis (out "
0028         "of three) differ by this value (default: "
0029         __stringify(DEFAULT_SAMPLE_TOLERANCE) ") or more, the reading "
0030         "is supposed to be wrong and is discarded.  Set to 0 to "
0031         "disable this check.");
0032
0033 struct mc13783_ts_priv {
0034     struct input_dev *idev;
0035     struct mc13xxx *mc13xxx;
0036     struct delayed_work work;
0037     unsigned int sample[4];
0038     struct mc13xxx_ts_platform_data *touch;
0039 };
0040
0041 static irqreturn_t mc13783_ts_handler(int irq, void *data)
0042 {
0043     struct mc13783_ts_priv *priv = data;
0044
0045     mc13xxx_irq_ack(priv->mc13xxx, irq);
0046
0047     /*
0048      * Kick off reading coordinates. Note that if work happens already
0049      * be queued for future execution (it rearms itself) it will not
0050      * be rescheduled for immediate execution here. However the rearm
0051      * delay is HZ / 50 which is acceptable.
0052      */
0053     schedule_delayed_work(&priv->work, 0);
0054
0055     return IRQ_HANDLED;
0056 }
0057
0058 #define sort3(a0, a1, a2) ({                        \
0059         if (a0 > a1)                        \
0060             swap(a0, a1);                   \
0061         if (a1 > a2)                        \
0062             swap(a1, a2);                   \
0063         if (a0 > a1)                        \
0064             swap(a0, a1);                   \
0065         })
0066
0067 static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
0068 {
0069     struct input_dev *idev = priv->idev;
0070     int x0, x1, x2, y0, y1, y2;
0071     int cr0, cr1;
0072
0073     /*
0074      * the values are 10-bit wide only, but the two least significant
0075      * bits are for future 12 bit use and reading yields 0
0076      */
0077     x0 = priv->sample[0] & 0xfff;
0078     x1 = priv->sample[1] & 0xfff;
0079     x2 = priv->sample[2] & 0xfff;
0080     y0 = priv->sample[3] & 0xfff;
0081     y1 = (priv->sample[0] >> 12) & 0xfff;
0082     y2 = (priv->sample[1] >> 12) & 0xfff;
0083     cr0 = (priv->sample[2] >> 12) & 0xfff;
0084     cr1 = (priv->sample[3] >> 12) & 0xfff;
0085
0086     dev_dbg(&idev->dev,
0087         "x: (% 4d,% 4d,% 4d) y: (% 4d, % 4d,% 4d) cr: (% 4d, % 4d)\n",
0088         x0, x1, x2, y0, y1, y2, cr0, cr1);
0089
0090     sort3(x0, x1, x2);
0091     sort3(y0, y1, y2);
0092
0093     cr0 = (cr0 + cr1) / 2;
0094
0095     if (!cr0 || !sample_tolerance ||
0096             (x2 - x0 < sample_tolerance &&
0097              y2 - y0 < sample_tolerance)) {
0098         /* report the median coordinate and average pressure */
0099         if (cr0) {
0100             input_report_abs(idev, ABS_X, x1);
0101             input_report_abs(idev, ABS_Y, y1);
0102
0103             dev_dbg(&idev->dev, "report (%d, %d, %d)\n",
0104                     x1, y1, 0x1000 - cr0);
0105             schedule_delayed_work(&priv->work, HZ / 50);
0106         } else {
0107             dev_dbg(&idev->dev, "report release\n");
0108         }
0109
0110         input_report_abs(idev, ABS_PRESSURE,
0111                 cr0 ? 0x1000 - cr0 : cr0);
0112         input_report_key(idev, BTN_TOUCH, cr0);
0113         input_sync(idev);
0114     } else {
0115         dev_dbg(&idev->dev, "discard event\n");
0116     }
0117 }
0118
0119 static void mc13783_ts_work(struct work_struct *work)
0120 {
0121     struct mc13783_ts_priv *priv =
0122         container_of(work, struct mc13783_ts_priv, work.work);
0123     unsigned int mode = MC13XXX_ADC_MODE_TS;
0124     unsigned int channel = 12;
0125
0126     if (mc13xxx_adc_do_conversion(priv->mc13xxx,
0127                 mode, channel,
0128                 priv->touch->ato, priv->touch->atox,
0129                 priv->sample) == 0)
0130         mc13783_ts_report_sample(priv);
0131 }
0132
0133 static int mc13783_ts_open(struct input_dev *dev)
0134 {
0135     struct mc13783_ts_priv *priv = input_get_drvdata(dev);
0136     int ret;
0137
0138     mc13xxx_lock(priv->mc13xxx);
0139
0140     mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TS);
0141
0142     ret = mc13xxx_irq_request(priv->mc13xxx, MC13XXX_IRQ_TS,
0143         mc13783_ts_handler, MC13783_TS_NAME, priv);
0144     if (ret)
0145         goto out;
0146
0147     ret = mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
0148             MC13XXX_ADC0_TSMOD_MASK, MC13XXX_ADC0_TSMOD0);
0149     if (ret)
0150         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
0151 out:
0152     mc13xxx_unlock(priv->mc13xxx);
0153     return ret;
0154 }
0155
0156 static void mc13783_ts_close(struct input_dev *dev)
0157 {
0158     struct mc13783_ts_priv *priv = input_get_drvdata(dev);
0159
0160     mc13xxx_lock(priv->mc13xxx);
0161     mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
0162             MC13XXX_ADC0_TSMOD_MASK, 0);
0163     mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
0164     mc13xxx_unlock(priv->mc13xxx);
0165
0166     cancel_delayed_work_sync(&priv->work);
0167 }
0168
0169 static int __init mc13783_ts_probe(struct platform_device *pdev)
0170 {
0171     struct mc13783_ts_priv *priv;
0172     struct input_dev *idev;
0173     int ret = -ENOMEM;
0174
0175     priv = kzalloc(sizeof(*priv), GFP_KERNEL);
0176     idev = input_allocate_device();
0177     if (!priv || !idev)
0178         goto err_free_mem;
0179
0180     INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
0181     priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
0182     priv->idev = idev;
0183     priv->touch = dev_get_platdata(&pdev->dev);
0184     if (!priv->touch) {
0185         dev_err(&pdev->dev, "missing platform data\n");
0186         ret = -ENODEV;
0187         goto err_free_mem;
0188     }
0189
0190     idev->name = MC13783_TS_NAME;
0191     idev->dev.parent = &pdev->dev;
0192
0193     idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
0194     idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
0195     input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
0196     input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
0197     input_set_abs_params(idev, ABS_PRESSURE, 0, 0xfff, 0, 0);
0198
0199     idev->open = mc13783_ts_open;
0200     idev->close = mc13783_ts_close;
0201
0202     input_set_drvdata(idev, priv);
0203
0204     ret = input_register_device(priv->idev);
0205     if (ret) {
0206         dev_err(&pdev->dev,
0207             "register input device failed with %d\n", ret);
0208         goto err_free_mem;
0209     }
0210
0211     platform_set_drvdata(pdev, priv);
0212     return 0;
0213
0214 err_free_mem:
0215     input_free_device(idev);
0216     kfree(priv);
0217     return ret;
0218 }
0219
0220 static int mc13783_ts_remove(struct platform_device *pdev)
0221 {
0222     struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);
0223
0224     input_unregister_device(priv->idev);
0225     kfree(priv);
0226
0227     return 0;
0228 }
0229
0230 static struct platform_driver mc13783_ts_driver = {
0231     .remove     = mc13783_ts_remove,
0232     .driver     = {
0233         .name   = MC13783_TS_NAME,
0234     },
0235 };
0236
0237 module_platform_driver_probe(mc13783_ts_driver, mc13783_ts_probe);
0238
0239 MODULE_DESCRIPTION("MC13783 input touchscreen driver");
0240 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
0241 MODULE_LICENSE("GPL v2");
0242 MODULE_ALIAS("platform:" MC13783_TS_NAME);