input/touchscreen/mtouch.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * MicroTouch (3M) serial touchscreen driver
0004  *
0005  * Copyright (c) 2004 Vojtech Pavlik
0006  */
0007
0008
0009 /*
0010  * 2005/02/19 Dan Streetman <ddstreet@ieee.org>
0011  *   Copied elo.c and edited for MicroTouch protocol
0012  */
0013
0014 #include <linux/errno.h>
0015 #include <linux/kernel.h>
0016 #include <linux/module.h>
0017 #include <linux/slab.h>
0018 #include <linux/input.h>
0019 #include <linux/serio.h>
0020
0021 #define DRIVER_DESC "MicroTouch serial touchscreen driver"
0022
0023 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
0024 MODULE_DESCRIPTION(DRIVER_DESC);
0025 MODULE_LICENSE("GPL");
0026
0027 /*
0028  * Definitions & global arrays.
0029  */
0030
0031 #define MTOUCH_FORMAT_TABLET_STATUS_BIT 0x80
0032 #define MTOUCH_FORMAT_TABLET_TOUCH_BIT 0x40
0033 #define MTOUCH_FORMAT_TABLET_LENGTH 5
0034 #define MTOUCH_RESPONSE_BEGIN_BYTE 0x01
0035 #define MTOUCH_RESPONSE_END_BYTE 0x0d
0036
0037 /* todo: check specs for max length of all responses */
0038 #define MTOUCH_MAX_LENGTH 16
0039
0040 #define MTOUCH_MIN_XC 0
0041 #define MTOUCH_MAX_XC 0x3fff
0042 #define MTOUCH_MIN_YC 0
0043 #define MTOUCH_MAX_YC 0x3fff
0044
0045 #define MTOUCH_GET_XC(data) (((data[2])<<7) | data[1])
0046 #define MTOUCH_GET_YC(data) (((data[4])<<7) | data[3])
0047 #define MTOUCH_GET_TOUCHED(data) (MTOUCH_FORMAT_TABLET_TOUCH_BIT & data[0])
0048
0049 /*
0050  * Per-touchscreen data.
0051  */
0052
0053 struct mtouch {
0054     struct input_dev *dev;
0055     struct serio *serio;
0056     int idx;
0057     unsigned char data[MTOUCH_MAX_LENGTH];
0058     char phys[32];
0059 };
0060
0061 static void mtouch_process_format_tablet(struct mtouch *mtouch)
0062 {
0063     struct input_dev *dev = mtouch->dev;
0064
0065     if (MTOUCH_FORMAT_TABLET_LENGTH == ++mtouch->idx) {
0066         input_report_abs(dev, ABS_X, MTOUCH_GET_XC(mtouch->data));
0067         input_report_abs(dev, ABS_Y, MTOUCH_MAX_YC - MTOUCH_GET_YC(mtouch->data));
0068         input_report_key(dev, BTN_TOUCH, MTOUCH_GET_TOUCHED(mtouch->data));
0069         input_sync(dev);
0070
0071         mtouch->idx = 0;
0072     }
0073 }
0074
0075 static void mtouch_process_response(struct mtouch *mtouch)
0076 {
0077     if (MTOUCH_RESPONSE_END_BYTE == mtouch->data[mtouch->idx++]) {
0078         /* FIXME - process response */
0079         mtouch->idx = 0;
0080     } else if (MTOUCH_MAX_LENGTH == mtouch->idx) {
0081         printk(KERN_ERR "mtouch.c: too many response bytes\n");
0082         mtouch->idx = 0;
0083     }
0084 }
0085
0086 static irqreturn_t mtouch_interrupt(struct serio *serio,
0087         unsigned char data, unsigned int flags)
0088 {
0089     struct mtouch *mtouch = serio_get_drvdata(serio);
0090
0091     mtouch->data[mtouch->idx] = data;
0092
0093     if (MTOUCH_FORMAT_TABLET_STATUS_BIT & mtouch->data[0])
0094         mtouch_process_format_tablet(mtouch);
0095     else if (MTOUCH_RESPONSE_BEGIN_BYTE == mtouch->data[0])
0096         mtouch_process_response(mtouch);
0097     else
0098         printk(KERN_DEBUG "mtouch.c: unknown/unsynchronized data from device, byte %x\n",mtouch->data[0]);
0099
0100     return IRQ_HANDLED;
0101 }
0102
0103 /*
0104  * mtouch_disconnect() is the opposite of mtouch_connect()
0105  */
0106
0107 static void mtouch_disconnect(struct serio *serio)
0108 {
0109     struct mtouch *mtouch = serio_get_drvdata(serio);
0110
0111     input_get_device(mtouch->dev);
0112     input_unregister_device(mtouch->dev);
0113     serio_close(serio);
0114     serio_set_drvdata(serio, NULL);
0115     input_put_device(mtouch->dev);
0116     kfree(mtouch);
0117 }
0118
0119 /*
0120  * mtouch_connect() is the routine that is called when someone adds a
0121  * new serio device that supports MicroTouch (Format Tablet) protocol and registers it as
0122  * an input device.
0123  */
0124
0125 static int mtouch_connect(struct serio *serio, struct serio_driver *drv)
0126 {
0127     struct mtouch *mtouch;
0128     struct input_dev *input_dev;
0129     int err;
0130
0131     mtouch = kzalloc(sizeof(struct mtouch), GFP_KERNEL);
0132     input_dev = input_allocate_device();
0133     if (!mtouch || !input_dev) {
0134         err = -ENOMEM;
0135         goto fail1;
0136     }
0137
0138     mtouch->serio = serio;
0139     mtouch->dev = input_dev;
0140     snprintf(mtouch->phys, sizeof(mtouch->phys), "%s/input0", serio->phys);
0141
0142     input_dev->name = "MicroTouch Serial TouchScreen";
0143     input_dev->phys = mtouch->phys;
0144     input_dev->id.bustype = BUS_RS232;
0145     input_dev->id.vendor = SERIO_MICROTOUCH;
0146     input_dev->id.product = 0;
0147     input_dev->id.version = 0x0100;
0148     input_dev->dev.parent = &serio->dev;
0149     input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
0150     input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
0151     input_set_abs_params(mtouch->dev, ABS_X, MTOUCH_MIN_XC, MTOUCH_MAX_XC, 0, 0);
0152     input_set_abs_params(mtouch->dev, ABS_Y, MTOUCH_MIN_YC, MTOUCH_MAX_YC, 0, 0);
0153
0154     serio_set_drvdata(serio, mtouch);
0155
0156     err = serio_open(serio, drv);
0157     if (err)
0158         goto fail2;
0159
0160     err = input_register_device(mtouch->dev);
0161     if (err)
0162         goto fail3;
0163
0164     return 0;
0165
0166  fail3: serio_close(serio);
0167  fail2: serio_set_drvdata(serio, NULL);
0168  fail1: input_free_device(input_dev);
0169     kfree(mtouch);
0170     return err;
0171 }
0172
0173 /*
0174  * The serio driver structure.
0175  */
0176
0177 static const struct serio_device_id mtouch_serio_ids[] = {
0178     {
0179         .type   = SERIO_RS232,
0180         .proto  = SERIO_MICROTOUCH,
0181         .id = SERIO_ANY,
0182         .extra  = SERIO_ANY,
0183     },
0184     { 0 }
0185 };
0186
0187 MODULE_DEVICE_TABLE(serio, mtouch_serio_ids);
0188
0189 static struct serio_driver mtouch_drv = {
0190     .driver     = {
0191         .name   = "mtouch",
0192     },
0193     .description    = DRIVER_DESC,
0194     .id_table   = mtouch_serio_ids,
0195     .interrupt  = mtouch_interrupt,
0196     .connect    = mtouch_connect,
0197     .disconnect = mtouch_disconnect,
0198 };
0199
0200 module_serio_driver(mtouch_drv);