1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Hampshire serial touchscreen driver 4 * 5 * Copyright (c) 2010 Adam Bennett 6 * Based on the dynapro driver (c) Tias Guns 7 */ 8 9 10 /* 11 * 2010/04/08 Adam Bennett <abennett72@gmail.com> 12 * Copied dynapro.c and edited for Hampshire 4-byte protocol 13 */ 14 15 #include <linux/errno.h> 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/slab.h> 19 #include <linux/input.h> 20 #include <linux/serio.h> 21 22 #define DRIVER_DESC "Hampshire serial touchscreen driver" 23 24 MODULE_AUTHOR("Adam Bennett <abennett72@gmail.com>"); 25 MODULE_DESCRIPTION(DRIVER_DESC); 26 MODULE_LICENSE("GPL"); 27 28 /* 29 * Definitions & global arrays. 30 */ 31 32 #define HAMPSHIRE_FORMAT_TOUCH_BIT 0x40 33 #define HAMPSHIRE_FORMAT_LENGTH 4 34 #define HAMPSHIRE_RESPONSE_BEGIN_BYTE 0x80 35 36 #define HAMPSHIRE_MIN_XC 0 37 #define HAMPSHIRE_MAX_XC 0x1000 38 #define HAMPSHIRE_MIN_YC 0 39 #define HAMPSHIRE_MAX_YC 0x1000 40 41 #define HAMPSHIRE_GET_XC(data) (((data[3] & 0x0c) >> 2) | (data[1] << 2) | ((data[0] & 0x38) << 6)) 42 #define HAMPSHIRE_GET_YC(data) ((data[3] & 0x03) | (data[2] << 2) | ((data[0] & 0x07) << 9)) 43 #define HAMPSHIRE_GET_TOUCHED(data) (HAMPSHIRE_FORMAT_TOUCH_BIT & data[0]) 44 45 /* 46 * Per-touchscreen data. 47 */ 48 49 struct hampshire { 50 struct input_dev *dev; 51 struct serio *serio; 52 int idx; 53 unsigned char data[HAMPSHIRE_FORMAT_LENGTH]; 54 char phys[32]; 55 }; 56 57 static void hampshire_process_data(struct hampshire *phampshire) 58 { 59 struct input_dev *dev = phampshire->dev; 60 61 if (HAMPSHIRE_FORMAT_LENGTH == ++phampshire->idx) { 62 input_report_abs(dev, ABS_X, HAMPSHIRE_GET_XC(phampshire->data)); 63 input_report_abs(dev, ABS_Y, HAMPSHIRE_GET_YC(phampshire->data)); 64 input_report_key(dev, BTN_TOUCH, 65 HAMPSHIRE_GET_TOUCHED(phampshire->data)); 66 input_sync(dev); 67 68 phampshire->idx = 0; 69 } 70 } 71 72 static irqreturn_t hampshire_interrupt(struct serio *serio, 73 unsigned char data, unsigned int flags) 74 { 75 struct hampshire *phampshire = serio_get_drvdata(serio); 76 77 phampshire->data[phampshire->idx] = data; 78 79 if (HAMPSHIRE_RESPONSE_BEGIN_BYTE & phampshire->data[0]) 80 hampshire_process_data(phampshire); 81 else 82 dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n", 83 phampshire->data[0]); 84 85 return IRQ_HANDLED; 86 } 87 88 static void hampshire_disconnect(struct serio *serio) 89 { 90 struct hampshire *phampshire = serio_get_drvdata(serio); 91 92 input_get_device(phampshire->dev); 93 input_unregister_device(phampshire->dev); 94 serio_close(serio); 95 serio_set_drvdata(serio, NULL); 96 input_put_device(phampshire->dev); 97 kfree(phampshire); 98 } 99 100 /* 101 * hampshire_connect() is the routine that is called when someone adds a 102 * new serio device that supports hampshire protocol and registers it as 103 * an input device. This is usually accomplished using inputattach. 104 */ 105 106 static int hampshire_connect(struct serio *serio, struct serio_driver *drv) 107 { 108 struct hampshire *phampshire; 109 struct input_dev *input_dev; 110 int err; 111 112 phampshire = kzalloc(sizeof(struct hampshire), GFP_KERNEL); 113 input_dev = input_allocate_device(); 114 if (!phampshire || !input_dev) { 115 err = -ENOMEM; 116 goto fail1; 117 } 118 119 phampshire->serio = serio; 120 phampshire->dev = input_dev; 121 snprintf(phampshire->phys, sizeof(phampshire->phys), 122 "%s/input0", serio->phys); 123 124 input_dev->name = "Hampshire Serial TouchScreen"; 125 input_dev->phys = phampshire->phys; 126 input_dev->id.bustype = BUS_RS232; 127 input_dev->id.vendor = SERIO_HAMPSHIRE; 128 input_dev->id.product = 0; 129 input_dev->id.version = 0x0001; 130 input_dev->dev.parent = &serio->dev; 131 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 132 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); 133 input_set_abs_params(phampshire->dev, ABS_X, 134 HAMPSHIRE_MIN_XC, HAMPSHIRE_MAX_XC, 0, 0); 135 input_set_abs_params(phampshire->dev, ABS_Y, 136 HAMPSHIRE_MIN_YC, HAMPSHIRE_MAX_YC, 0, 0); 137 138 serio_set_drvdata(serio, phampshire); 139 140 err = serio_open(serio, drv); 141 if (err) 142 goto fail2; 143 144 err = input_register_device(phampshire->dev); 145 if (err) 146 goto fail3; 147 148 return 0; 149 150 fail3: serio_close(serio); 151 fail2: serio_set_drvdata(serio, NULL); 152 fail1: input_free_device(input_dev); 153 kfree(phampshire); 154 return err; 155 } 156 157 /* 158 * The serio driver structure. 159 */ 160 161 static const struct serio_device_id hampshire_serio_ids[] = { 162 { 163 .type = SERIO_RS232, 164 .proto = SERIO_HAMPSHIRE, 165 .id = SERIO_ANY, 166 .extra = SERIO_ANY, 167 }, 168 { 0 } 169 }; 170 171 MODULE_DEVICE_TABLE(serio, hampshire_serio_ids); 172 173 static struct serio_driver hampshire_drv = { 174 .driver = { 175 .name = "hampshire", 176 }, 177 .description = DRIVER_DESC, 178 .id_table = hampshire_serio_ids, 179 .interrupt = hampshire_interrupt, 180 .connect = hampshire_connect, 181 .disconnect = hampshire_disconnect, 182 }; 183 184 module_serio_driver(hampshire_drv); 185