1 /* 2 * TSC-40 serial touchscreen driver. It should be compatible with 3 * TSC-10 and 25. 4 * 5 * Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> 6 * License: GPLv2 as published by the FSF. 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/slab.h> 12 #include <linux/input.h> 13 #include <linux/serio.h> 14 15 #define PACKET_LENGTH 5 16 struct tsc_ser { 17 struct input_dev *dev; 18 struct serio *serio; 19 u32 idx; 20 unsigned char data[PACKET_LENGTH]; 21 char phys[32]; 22 }; 23 24 static void tsc_process_data(struct tsc_ser *ptsc) 25 { 26 struct input_dev *dev = ptsc->dev; 27 u8 *data = ptsc->data; 28 u32 x; 29 u32 y; 30 31 x = ((data[1] & 0x03) << 8) | data[2]; 32 y = ((data[3] & 0x03) << 8) | data[4]; 33 34 input_report_abs(dev, ABS_X, x); 35 input_report_abs(dev, ABS_Y, y); 36 input_report_key(dev, BTN_TOUCH, 1); 37 38 input_sync(dev); 39 } 40 41 static irqreturn_t tsc_interrupt(struct serio *serio, 42 unsigned char data, unsigned int flags) 43 { 44 struct tsc_ser *ptsc = serio_get_drvdata(serio); 45 struct input_dev *dev = ptsc->dev; 46 47 ptsc->data[ptsc->idx] = data; 48 switch (ptsc->idx++) { 49 case 0: 50 if (unlikely((data & 0x3e) != 0x10)) { 51 dev_dbg(&serio->dev, 52 "unsynchronized packet start (0x%02x)\n", data); 53 ptsc->idx = 0; 54 } else if (!(data & 0x01)) { 55 input_report_key(dev, BTN_TOUCH, 0); 56 input_sync(dev); 57 ptsc->idx = 0; 58 } 59 break; 60 61 case 1: 62 case 3: 63 if (unlikely(data & 0xfc)) { 64 dev_dbg(&serio->dev, 65 "unsynchronized data 0x%02x at offset %d\n", 66 data, ptsc->idx - 1); 67 ptsc->idx = 0; 68 } 69 break; 70 71 case 4: 72 tsc_process_data(ptsc); 73 ptsc->idx = 0; 74 break; 75 } 76 77 return IRQ_HANDLED; 78 } 79 80 static int tsc_connect(struct serio *serio, struct serio_driver *drv) 81 { 82 struct tsc_ser *ptsc; 83 struct input_dev *input_dev; 84 int error; 85 86 ptsc = kzalloc(sizeof(struct tsc_ser), GFP_KERNEL); 87 input_dev = input_allocate_device(); 88 if (!ptsc || !input_dev) { 89 error = -ENOMEM; 90 goto fail1; 91 } 92 93 ptsc->serio = serio; 94 ptsc->dev = input_dev; 95 snprintf(ptsc->phys, sizeof(ptsc->phys), "%s/input0", serio->phys); 96 97 input_dev->name = "TSC-10/25/40 Serial TouchScreen"; 98 input_dev->phys = ptsc->phys; 99 input_dev->id.bustype = BUS_RS232; 100 input_dev->id.vendor = SERIO_TSC40; 101 input_dev->id.product = 40; 102 input_dev->id.version = 0x0001; 103 input_dev->dev.parent = &serio->dev; 104 105 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 106 __set_bit(BTN_TOUCH, input_dev->keybit); 107 input_set_abs_params(ptsc->dev, ABS_X, 0, 0x3ff, 0, 0); 108 input_set_abs_params(ptsc->dev, ABS_Y, 0, 0x3ff, 0, 0); 109 110 serio_set_drvdata(serio, ptsc); 111 112 error = serio_open(serio, drv); 113 if (error) 114 goto fail2; 115 116 error = input_register_device(ptsc->dev); 117 if (error) 118 goto fail3; 119 120 return 0; 121 122 fail3: 123 serio_close(serio); 124 fail2: 125 serio_set_drvdata(serio, NULL); 126 fail1: 127 input_free_device(input_dev); 128 kfree(ptsc); 129 return error; 130 } 131 132 static void tsc_disconnect(struct serio *serio) 133 { 134 struct tsc_ser *ptsc = serio_get_drvdata(serio); 135 136 serio_close(serio); 137 138 input_unregister_device(ptsc->dev); 139 kfree(ptsc); 140 141 serio_set_drvdata(serio, NULL); 142 } 143 144 static struct serio_device_id tsc_serio_ids[] = { 145 { 146 .type = SERIO_RS232, 147 .proto = SERIO_TSC40, 148 .id = SERIO_ANY, 149 .extra = SERIO_ANY, 150 }, 151 { 0 } 152 }; 153 MODULE_DEVICE_TABLE(serio, tsc_serio_ids); 154 155 #define DRIVER_DESC "TSC-10/25/40 serial touchscreen driver" 156 157 static struct serio_driver tsc_drv = { 158 .driver = { 159 .name = "tsc40", 160 }, 161 .description = DRIVER_DESC, 162 .id_table = tsc_serio_ids, 163 .interrupt = tsc_interrupt, 164 .connect = tsc_connect, 165 .disconnect = tsc_disconnect, 166 }; 167 168 module_serio_driver(tsc_drv); 169 170 MODULE_AUTHOR("Sebastian Andrzej Siewior <bigeasy@linutronix.de>"); 171 MODULE_DESCRIPTION(DRIVER_DESC); 172 MODULE_LICENSE("GPL v2"); 173