/* * Driver for I2C connected EETI EXC3000 multiple touch controller * * Copyright (C) 2017 Ahmet Inan <inan@distec.de> * * minimal implementation based on egalax_ts.c and egalax_i2c.c * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/bitops.h> #include <linux/device.h> #include <linux/i2c.h> #include <linux/input.h> #include <linux/input/mt.h> #include <linux/input/touchscreen.h> #include <linux/interrupt.h> #include <linux/module.h> #include <linux/of.h> #include <linux/timer.h> #include <asm/unaligned.h> #define EXC3000_NUM_SLOTS 10 #define EXC3000_SLOTS_PER_FRAME 5 #define EXC3000_LEN_FRAME 66 #define EXC3000_LEN_POINT 10 #define EXC3000_MT_EVENT 6 #define EXC3000_TIMEOUT_MS 100 struct exc3000_data { struct i2c_client *client; struct input_dev *input; struct touchscreen_properties prop; struct timer_list timer; u8 buf[2 * EXC3000_LEN_FRAME]; }; static void exc3000_report_slots(struct input_dev *input, struct touchscreen_properties *prop, const u8 *buf, int num) { for (; num--; buf += EXC3000_LEN_POINT) { if (buf[0] & BIT(0)) { input_mt_slot(input, buf[1]); input_mt_report_slot_state(input, MT_TOOL_FINGER, true); touchscreen_report_pos(input, prop, get_unaligned_le16(buf + 2), get_unaligned_le16(buf + 4), true); } } } static void exc3000_timer(struct timer_list *t) { struct exc3000_data *data = from_timer(data, t, timer); input_mt_sync_frame(data->input); input_sync(data->input); } static int exc3000_read_frame(struct i2c_client *client, u8 *buf) { int ret; ret = i2c_master_send(client, "'", 2); if (ret < 0) return ret; if (ret != 2) return -EIO; ret = i2c_master_recv(client, buf, EXC3000_LEN_FRAME); if (ret < 0) return ret; if (ret != EXC3000_LEN_FRAME) return -EIO; if (get_unaligned_le16(buf) != EXC3000_LEN_FRAME || buf[2] != EXC3000_MT_EVENT) return -EINVAL; return 0; } static int exc3000_read_data(struct i2c_client *client, u8 *buf, int *n_slots) { int error; error = exc3000_read_frame(client, buf); if (error) return error; *n_slots = buf[3]; if (!*n_slots || *n_slots > EXC3000_NUM_SLOTS) return -EINVAL; if (*n_slots > EXC3000_SLOTS_PER_FRAME) { /* Read 2nd frame to get the rest of the contacts. */ error = exc3000_read_frame(client, buf + EXC3000_LEN_FRAME); if (error) return error; /* 2nd chunk must have number of contacts set to 0. */ if (buf[EXC3000_LEN_FRAME + 3] != 0) return -EINVAL; } return 0; } static irqreturn_t exc3000_interrupt(int irq, void *dev_id) { struct exc3000_data *data = dev_id; struct input_dev *input = data->input; u8 *buf = data->buf; int slots, total_slots; int error; error = exc3000_read_data(data->client, buf, &total_slots); if (error) { /* Schedule a timer to release "stuck" contacts */ mod_timer(&data->timer, jiffies + msecs_to_jiffies(EXC3000_TIMEOUT_MS)); goto out; } /* * We read full state successfully, no contacts will be "stuck". */ del_timer_sync(&data->timer); while (total_slots > 0) { slots = min(total_slots, EXC3000_SLOTS_PER_FRAME); exc3000_report_slots(input, &data->prop, buf + 4, slots); total_slots -= slots; buf += EXC3000_LEN_FRAME; } input_mt_sync_frame(input); input_sync(input); out: return IRQ_HANDLED; } static int exc3000_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct exc3000_data *data; struct input_dev *input; int error; data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; data->client = client; timer_setup(&data->timer, exc3000_timer, 0); input = devm_input_allocate_device(&client->dev); if (!input) return -ENOMEM; data->input = input; input->name = "EETI EXC3000 Touch Screen"; input->id.bustype = BUS_I2C; input_set_abs_params(input, ABS_MT_POSITION_X, 0, 4095, 0, 0); input_set_abs_params(input, ABS_MT_POSITION_Y, 0, 4095, 0, 0); touchscreen_parse_properties(input, true, &data->prop); error = input_mt_init_slots(input, EXC3000_NUM_SLOTS, INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED); if (error) return error; error = input_register_device(input); if (error) return error; error = devm_request_threaded_irq(&client->dev, client->irq, NULL, exc3000_interrupt, IRQF_ONESHOT, client->name, data); if (error) return error; return 0; } static const struct i2c_device_id exc3000_id[] = { { "exc3000", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, exc3000_id); #ifdef CONFIG_OF static const struct of_device_id exc3000_of_match[] = { { .compatible = "eeti,exc3000" }, { } }; MODULE_DEVICE_TABLE(of, exc3000_of_match); #endif static struct i2c_driver exc3000_driver = { .driver = { .name = "exc3000", .of_match_table = of_match_ptr(exc3000_of_match), }, .id_table = exc3000_id, .probe = exc3000_probe, }; module_i2c_driver(exc3000_driver); MODULE_AUTHOR("Ahmet Inan <inan@distec.de>"); MODULE_DESCRIPTION("I2C connected EETI EXC3000 multiple touch controller driver"); MODULE_LICENSE("GPL v2");