diff options
Diffstat (limited to 'drivers/input/touchscreen/exc3000.c')
| -rw-r--r-- | drivers/input/touchscreen/exc3000.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/exc3000.c b/drivers/input/touchscreen/exc3000.c new file mode 100644 index 000000000000..37437a53cd1a --- /dev/null +++ b/drivers/input/touchscreen/exc3000.c @@ -0,0 +1,223 @@ +/* + * 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"); |