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![Oleh Kravchenko](/assets/img/avatar_default.png)
A simple analog joystick built on Low Power ATtiny85 Microcontroller. Directional movements are measured with two 10 kΩ potentiometers connected with a gimbal mechanism that separates the horizontal and vertical movements. This joystick also has a select button that is actuated when the joystick is pressed down. Input events polled over the I2C bus. Product page: https://www.sparkfun.com/products/15168 Firmware and hardware sources: https://github.com/sparkfun/Qwiic_Joystick Tested on RPi4B and O4-iMX-NANO boards. Signed-off-by: Oleh Kravchenko <oleg@kaa.org.ua> Reviewed-by: Jeff LaBundy <jeff@labundy.com> Link: https://lore.kernel.org/r/20210608223130.16830-2-oleg@kaa.org.ua Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
146 lines
3.5 KiB
C
146 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2021 Oleh Kravchenko <oleg@kaa.org.ua>
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*
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* SparkFun Qwiic Joystick
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* Product page:https://www.sparkfun.com/products/15168
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* Firmware and hardware sources:https://github.com/sparkfun/Qwiic_Joystick
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*/
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#include <linux/bits.h>
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#include <linux/i2c.h>
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#include <linux/input.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#define DRV_NAME "qwiic-joystick"
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#define QWIIC_JSK_REG_VERS 1
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#define QWIIC_JSK_REG_DATA 3
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#define QWIIC_JSK_MAX_AXIS GENMASK(9, 0)
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#define QWIIC_JSK_FUZZ 2
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#define QWIIC_JSK_FLAT 2
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#define QWIIC_JSK_POLL_INTERVAL 16
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#define QWIIC_JSK_POLL_MIN 8
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#define QWIIC_JSK_POLL_MAX 32
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struct qwiic_jsk {
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char phys[32];
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struct input_dev *dev;
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struct i2c_client *client;
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};
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struct qwiic_ver {
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u8 major;
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u8 minor;
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};
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struct qwiic_data {
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__be16 x;
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__be16 y;
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u8 thumb;
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};
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static void qwiic_poll(struct input_dev *input)
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{
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struct qwiic_jsk *priv = input_get_drvdata(input);
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struct qwiic_data data;
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int err;
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err = i2c_smbus_read_i2c_block_data(priv->client, QWIIC_JSK_REG_DATA,
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sizeof(data), (u8 *)&data);
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if (err != sizeof(data))
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return;
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input_report_abs(input, ABS_X, be16_to_cpu(data.x) >> 6);
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input_report_abs(input, ABS_Y, be16_to_cpu(data.y) >> 6);
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input_report_key(input, BTN_THUMBL, !data.thumb);
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input_sync(input);
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}
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static int qwiic_probe(struct i2c_client *client)
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{
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struct qwiic_jsk *priv;
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struct qwiic_ver vers;
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int err;
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err = i2c_smbus_read_i2c_block_data(client, QWIIC_JSK_REG_VERS,
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sizeof(vers), (u8 *)&vers);
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if (err < 0)
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return err;
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if (err != sizeof(vers))
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return -EIO;
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dev_dbg(&client->dev, "SparkFun Qwiic Joystick, FW: %u.%u\n",
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vers.major, vers.minor);
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priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->client = client;
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snprintf(priv->phys, sizeof(priv->phys),
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"i2c/%s", dev_name(&client->dev));
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i2c_set_clientdata(client, priv);
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priv->dev = devm_input_allocate_device(&client->dev);
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if (!priv->dev)
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return -ENOMEM;
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priv->dev->id.bustype = BUS_I2C;
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priv->dev->name = "SparkFun Qwiic Joystick";
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priv->dev->phys = priv->phys;
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input_set_drvdata(priv->dev, priv);
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input_set_abs_params(priv->dev, ABS_X, 0, QWIIC_JSK_MAX_AXIS,
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QWIIC_JSK_FUZZ, QWIIC_JSK_FLAT);
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input_set_abs_params(priv->dev, ABS_Y, 0, QWIIC_JSK_MAX_AXIS,
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QWIIC_JSK_FUZZ, QWIIC_JSK_FLAT);
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input_set_capability(priv->dev, EV_KEY, BTN_THUMBL);
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err = input_setup_polling(priv->dev, qwiic_poll);
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if (err) {
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dev_err(&client->dev, "failed to set up polling: %d\n", err);
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return err;
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}
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input_set_poll_interval(priv->dev, QWIIC_JSK_POLL_INTERVAL);
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input_set_min_poll_interval(priv->dev, QWIIC_JSK_POLL_MIN);
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input_set_max_poll_interval(priv->dev, QWIIC_JSK_POLL_MAX);
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err = input_register_device(priv->dev);
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if (err) {
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dev_err(&client->dev, "failed to register joystick: %d\n", err);
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return err;
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}
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return 0;
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}
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#ifdef CONFIG_OF
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static const struct of_device_id of_qwiic_match[] = {
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{ .compatible = "sparkfun,qwiic-joystick", },
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{ },
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};
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MODULE_DEVICE_TABLE(of, of_qwiic_match);
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#endif /* CONFIG_OF */
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static const struct i2c_device_id qwiic_id_table[] = {
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{ KBUILD_MODNAME, 0 },
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{ },
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};
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MODULE_DEVICE_TABLE(i2c, qwiic_id_table);
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static struct i2c_driver qwiic_driver = {
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.driver = {
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.name = DRV_NAME,
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.of_match_table = of_match_ptr(of_qwiic_match),
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},
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.id_table = qwiic_id_table,
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.probe_new = qwiic_probe,
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};
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module_i2c_driver(qwiic_driver);
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MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
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MODULE_DESCRIPTION("SparkFun Qwiic Joystick driver");
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MODULE_LICENSE("GPL v2");
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