Input: add SparkFun Qwiic Joystick driver

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>

diff --git a/drivers/input/joystick/Kconfig b/drivers/input/joystick/Kconfig
index 5e38899..7dfe8ea 100644 (file)
--- a/drivers/input/joystick/Kconfig
+++ b/drivers/input/joystick/Kconfig
@@ -372,6 +372,15 @@ config JOYSTICK_PXRC
          To compile this driver as a module, choose M here: the
          module will be called pxrc.
 
+config JOYSTICK_QWIIC
+       tristate "SparkFun Qwiic Joystick"
+       depends on I2C
+       help
+         Say Y here if you want to use the SparkFun Qwiic Joystick.
+
+         To compile this driver as a module, choose M here: the
+         module will be called qwiic-joystick.
+
 config JOYSTICK_FSIA6B
        tristate "FlySky FS-iA6B RC Receiver"
        select SERIO

diff --git a/drivers/input/joystick/Makefile b/drivers/input/joystick/Makefile
index 31d720c..5174b8a 100644 (file)
--- a/drivers/input/joystick/Makefile
+++ b/drivers/input/joystick/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_JOYSTICK_MAPLE)          += maplecontrol.o
 obj-$(CONFIG_JOYSTICK_N64)             += n64joy.o
 obj-$(CONFIG_JOYSTICK_PSXPAD_SPI)      += psxpad-spi.o
 obj-$(CONFIG_JOYSTICK_PXRC)            += pxrc.o
+obj-$(CONFIG_JOYSTICK_QWIIC)           += qwiic-joystick.o
 obj-$(CONFIG_JOYSTICK_SIDEWINDER)      += sidewinder.o
 obj-$(CONFIG_JOYSTICK_SPACEBALL)       += spaceball.o
 obj-$(CONFIG_JOYSTICK_SPACEORB)                += spaceorb.o

diff --git a/drivers/input/joystick/qwiic-joystick.c b/drivers/input/joystick/qwiic-joystick.c
new file mode 100644 (file)
index 0000000..d4da31c
--- /dev/null
+++ b/drivers/input/joystick/qwiic-joystick.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Oleh Kravchenko <oleg@kaa.org.ua>
+ *
+ * SparkFun Qwiic Joystick
+ * Product page:https://www.sparkfun.com/products/15168
+ * Firmware and hardware sources:https://github.com/sparkfun/Qwiic_Joystick
+ */
+
+#include <linux/bits.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#define DRV_NAME "qwiic-joystick"
+
+#define QWIIC_JSK_REG_VERS     1
+#define QWIIC_JSK_REG_DATA     3
+
+#define QWIIC_JSK_MAX_AXIS     GENMASK(9, 0)
+#define QWIIC_JSK_FUZZ         2
+#define QWIIC_JSK_FLAT         2
+#define QWIIC_JSK_POLL_INTERVAL        16
+#define QWIIC_JSK_POLL_MIN     8
+#define QWIIC_JSK_POLL_MAX     32
+
+struct qwiic_jsk {
+       char phys[32];
+       struct input_dev *dev;
+       struct i2c_client *client;
+};
+
+struct qwiic_ver {
+       u8 major;
+       u8 minor;
+};
+
+struct qwiic_data {
+       __be16 x;
+       __be16 y;
+       u8 thumb;
+};
+
+static void qwiic_poll(struct input_dev *input)
+{
+       struct qwiic_jsk *priv = input_get_drvdata(input);
+       struct qwiic_data data;
+       int err;
+
+       err = i2c_smbus_read_i2c_block_data(priv->client, QWIIC_JSK_REG_DATA,
+                                           sizeof(data), (u8 *)&data);
+       if (err != sizeof(data))
+               return;
+
+       input_report_abs(input, ABS_X, be16_to_cpu(data.x) >> 6);
+       input_report_abs(input, ABS_Y, be16_to_cpu(data.y) >> 6);
+       input_report_key(input, BTN_THUMBL, !data.thumb);
+       input_sync(input);
+}
+
+static int qwiic_probe(struct i2c_client *client)
+{
+       struct qwiic_jsk *priv;
+       struct qwiic_ver vers;
+       int err;
+
+       err = i2c_smbus_read_i2c_block_data(client, QWIIC_JSK_REG_VERS,
+                                           sizeof(vers), (u8 *)&vers);
+       if (err < 0)
+               return err;
+       if (err != sizeof(vers))
+               return -EIO;
+
+       dev_dbg(&client->dev, "SparkFun Qwiic Joystick, FW: %u.%u\n",
+               vers.major, vers.minor);
+
+       priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
+       if (!priv)
+               return -ENOMEM;
+
+       priv->client = client;
+       snprintf(priv->phys, sizeof(priv->phys),
+                "i2c/%s", dev_name(&client->dev));
+       i2c_set_clientdata(client, priv);
+
+       priv->dev = devm_input_allocate_device(&client->dev);
+       if (!priv->dev)
+               return -ENOMEM;
+
+       priv->dev->id.bustype = BUS_I2C;
+       priv->dev->name = "SparkFun Qwiic Joystick";
+       priv->dev->phys = priv->phys;
+       input_set_drvdata(priv->dev, priv);
+
+       input_set_abs_params(priv->dev, ABS_X, 0, QWIIC_JSK_MAX_AXIS,
+                            QWIIC_JSK_FUZZ, QWIIC_JSK_FLAT);
+       input_set_abs_params(priv->dev, ABS_Y, 0, QWIIC_JSK_MAX_AXIS,
+                            QWIIC_JSK_FUZZ, QWIIC_JSK_FLAT);
+       input_set_capability(priv->dev, EV_KEY, BTN_THUMBL);
+
+       err = input_setup_polling(priv->dev, qwiic_poll);
+       if (err) {
+               dev_err(&client->dev, "failed to set up polling: %d\n", err);
+               return err;
+       }
+       input_set_poll_interval(priv->dev, QWIIC_JSK_POLL_INTERVAL);
+       input_set_min_poll_interval(priv->dev, QWIIC_JSK_POLL_MIN);
+       input_set_max_poll_interval(priv->dev, QWIIC_JSK_POLL_MAX);
+
+       err = input_register_device(priv->dev);
+       if (err) {
+               dev_err(&client->dev, "failed to register joystick: %d\n", err);
+               return err;
+       }
+
+       return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_qwiic_match[] = {
+       { .compatible = "sparkfun,qwiic-joystick", },
+       { },
+};
+MODULE_DEVICE_TABLE(of, of_qwiic_match);
+#endif /* CONFIG_OF */
+
+static const struct i2c_device_id qwiic_id_table[] = {
+       { KBUILD_MODNAME, 0 },
+       { },
+};
+MODULE_DEVICE_TABLE(i2c, qwiic_id_table);
+
+static struct i2c_driver qwiic_driver = {
+       .driver = {
+               .name           = DRV_NAME,
+               .of_match_table = of_match_ptr(of_qwiic_match),
+       },
+       .id_table       = qwiic_id_table,
+       .probe_new      = qwiic_probe,
+};
+module_i2c_driver(qwiic_driver);
+
+MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
+MODULE_DESCRIPTION("SparkFun Qwiic Joystick driver");
+MODULE_LICENSE("GPL v2");