// SPDX-License-Identifier: GPL-2.0-only /* * EETI Egalax serial touchscreen driver * * Copyright (c) 2015 Zoltán Böszörményi <zboszor@pr.hu> * * based on the * * Hampshire serial touchscreen driver (Copyright (c) 2010 Adam Bennett) */ #include <linux/errno.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/input.h> #include <linux/serio.h> #define DRIVER_DESC "EETI Egalax serial touchscreen driver" /* * Definitions & global arrays. */ #define EGALAX_FORMAT_MAX_LENGTH 6 #define EGALAX_FORMAT_START_BIT BIT(7) #define EGALAX_FORMAT_PRESSURE_BIT BIT(6) #define EGALAX_FORMAT_TOUCH_BIT BIT(0) #define EGALAX_FORMAT_RESOLUTION_MASK 0x06 #define EGALAX_MIN_XC 0 #define EGALAX_MAX_XC 0x4000 #define EGALAX_MIN_YC 0 #define EGALAX_MAX_YC 0x4000 /* * Per-touchscreen data. */ struct egalax { struct input_dev *input; struct serio *serio; int idx; u8 data[EGALAX_FORMAT_MAX_LENGTH]; char phys[32]; }; static void egalax_process_data(struct egalax *egalax) { struct input_dev *dev = egalax->input; u8 *data = egalax->data; u16 x, y; u8 shift; u8 mask; shift = 3 - ((data[0] & EGALAX_FORMAT_RESOLUTION_MASK) >> 1); mask = 0xff >> (shift + 1); x = (((u16)(data[1] & mask) << 7) | (data[2] & 0x7f)) << shift; y = (((u16)(data[3] & mask) << 7) | (data[4] & 0x7f)) << shift; input_report_key(dev, BTN_TOUCH, data[0] & EGALAX_FORMAT_TOUCH_BIT); input_report_abs(dev, ABS_X, x); input_report_abs(dev, ABS_Y, y); input_sync(dev); } static irqreturn_t egalax_interrupt(struct serio *serio, unsigned char data, unsigned int flags) { struct egalax *egalax = serio_get_drvdata(serio); int pkt_len; egalax->data[egalax->idx++] = data; if (likely(egalax->data[0] & EGALAX_FORMAT_START_BIT)) { pkt_len = egalax->data[0] & EGALAX_FORMAT_PRESSURE_BIT ? 6 : 5; if (pkt_len == egalax->idx) { egalax_process_data(egalax); egalax->idx = 0; } } else { dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n", egalax->data[0]); egalax->idx = 0; } return IRQ_HANDLED; } /* * egalax_connect() is the routine that is called when someone adds a * new serio device that supports egalax protocol and registers it as * an input device. This is usually accomplished using inputattach. */ static int egalax_connect(struct serio *serio, struct serio_driver *drv) { struct egalax *egalax; struct input_dev *input_dev; int error; egalax = kzalloc(sizeof(struct egalax), GFP_KERNEL); input_dev = input_allocate_device(); if (!egalax || !input_dev) { error = -ENOMEM; goto err_free_mem; } egalax->serio = serio; egalax->input = input_dev; snprintf(egalax->phys, sizeof(egalax->phys), "%s/input0", serio->phys); input_dev->name = "EETI eGalaxTouch Serial TouchScreen"; input_dev->phys = egalax->phys; input_dev->id.bustype = BUS_RS232; input_dev->id.vendor = SERIO_EGALAX; input_dev->id.product = 0; input_dev->id.version = 0x0001; input_dev->dev.parent = &serio->dev; input_set_capability(input_dev, EV_KEY, BTN_TOUCH); input_set_abs_params(input_dev, ABS_X, EGALAX_MIN_XC, EGALAX_MAX_XC, 0, 0); input_set_abs_params(input_dev, ABS_Y, EGALAX_MIN_YC, EGALAX_MAX_YC, 0, 0); serio_set_drvdata(serio, egalax); error = serio_open(serio, drv); if (error) goto err_reset_drvdata; error = input_register_device(input_dev); if (error) goto err_close_serio; return 0; err_close_serio: serio_close(serio); err_reset_drvdata: serio_set_drvdata(serio, NULL); err_free_mem: input_free_device(input_dev); kfree(egalax); return error; } static void egalax_disconnect(struct serio *serio) { struct egalax *egalax = serio_get_drvdata(serio); serio_close(serio); serio_set_drvdata(serio, NULL); input_unregister_device(egalax->input); kfree(egalax); } /* * The serio driver structure. */ static const struct serio_device_id egalax_serio_ids[] = { { .type = SERIO_RS232, .proto = SERIO_EGALAX, .id = SERIO_ANY, .extra = SERIO_ANY, }, { 0 } }; MODULE_DEVICE_TABLE(serio, egalax_serio_ids); static struct serio_driver egalax_drv = { .driver = { .name = "egalax", }, .description = DRIVER_DESC, .id_table = egalax_serio_ids, .interrupt = egalax_interrupt, .connect = egalax_connect, .disconnect = egalax_disconnect, }; module_serio_driver(egalax_drv); MODULE_AUTHOR("Zoltán Böszörményi <zboszor@pr.hu>"); MODULE_DESCRIPTION(DRIVER_DESC); MODULE_LICENSE("GPL v2");