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/*
* 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");
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