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incubator-nuttx/drivers/input/nunchuck.c

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/****************************************************************************
* drivers/input/nunchuck.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/* This file provides a driver for a Nintendo Wii Nunchuck joystick device.
* The nunchuck joystick provides X/Y positional data as integer values.
* The analog positional data may also be accompanied by discrete button
* data.
*
* The nunchuck joystick driver exports a standard character driver
* interface. By convention, the nunchuck joystick is registered as an input
* device at /dev/nunchuckN where N uniquely identifies the driver instance.
*/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdbool.h>
#include <string.h>
#include <poll.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/mutex.h>
#include <nuttx/signal.h>
#include <nuttx/random.h>
#include <nuttx/fs/fs.h>
#include <nuttx/i2c/i2c_master.h>
#include <nuttx/input/nunchuck.h>
#include <nuttx/irq.h>
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure provides the state of one nunchuck joystick driver */
struct nunchuck_dev_s
{
FAR struct i2c_master_s *i2c_dev; /* I2C interface connected to Nunchuck */
nunchuck_buttonset_t nck_sample; /* Last sampled button states */
mutex_t nck_lock; /* Supports exclusive access to the device */
/* The following is a singly linked list of open references to the
* joystick device.
*/
FAR struct nunchuck_open_s *nck_open;
};
/* This structure describes the state of one open joystick driver instance */
struct nunchuck_open_s
{
/* Supports a singly linked list */
FAR struct nunchuck_open_s *nck_flink;
/* The following will be true if we are closing */
volatile bool nck_closing;
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* Character driver methods */
static int nunchuck_open(FAR struct file *filep);
static int nunchuck_close(FAR struct file *filep);
static ssize_t nunchuck_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static int nunchuck_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
/* I2C Helpers */
static int nunchuck_i2c_read(FAR struct nunchuck_dev_s *priv,
FAR uint8_t *regval, int len);
static int nunchuck_i2c_write(FAR struct nunchuck_dev_s *priv,
uint8_t const *data, int len);
static int nunchuck_sample(FAR struct nunchuck_dev_s *priv,
FAR struct nunchuck_sample_s *buffer);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_nunchuck_fops =
{
nunchuck_open, /* open */
nunchuck_close, /* close */
nunchuck_read, /* read */
NULL, /* write */
NULL, /* seek */
nunchuck_ioctl, /* ioctl */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: nunchuck_i2c_read
****************************************************************************/
static int nunchuck_i2c_read(FAR struct nunchuck_dev_s *priv,
FAR uint8_t *regval, int len)
{
struct i2c_config_s config;
int ret = -1;
/* Set up the I2C configuration */
config.frequency = NUNCHUCK_I2C_FREQ;
config.address = NUNCHUCK_ADDR;
config.addrlen = 7;
/* Read "len" bytes from regaddr */
ret = i2c_read(priv->i2c_dev, &config, regval, len);
if (ret < 0)
{
ierr ("i2c_read failed: %d\n", ret);
return ret;
}
return OK;
}
/****************************************************************************
* Name: nunchuck_i2c_write
****************************************************************************/
static int nunchuck_i2c_write(FAR struct nunchuck_dev_s *priv,
uint8_t const *data, int len)
{
struct i2c_config_s config;
int ret;
/* Set up the I2C configuration */
config.frequency = NUNCHUCK_I2C_FREQ;
config.address = NUNCHUCK_ADDR;
config.addrlen = 7;
/* Write the data */
ret = i2c_write(priv->i2c_dev, &config, data, len);
if (ret < 0)
{
ierr("ERROR: i2c_write failed: %d\n", ret);
}
return ret;
}
static int nunchuck_sample(FAR struct nunchuck_dev_s *priv,
FAR struct nunchuck_sample_s *buffer)
{
uint8_t cmd[2];
uint8_t data[6];
static bool initialized;
if (!initialized)
{
/* Start device */
cmd[0] = 0x40;
cmd[1] = 0x00;
nunchuck_i2c_write(priv, cmd, 2);
/* Delay 20ms */
nxsig_usleep(20 * 1000);
initialized = true;
}
/* Prepare to read */
cmd[0] = 0x00;
nunchuck_i2c_write(priv, cmd, 1);
/* Wait */
nxsig_usleep(1000);
/* Read data */
nunchuck_i2c_read(priv, &data[0], 1);
/* Wait */
nxsig_usleep(1000);
/* Wait */
nxsig_usleep(1000);
nunchuck_i2c_read(priv, &data[1], 1);
/* Wait */
nxsig_usleep(1000);
nunchuck_i2c_read(priv, &data[2], 1);
/* Wait */
nxsig_usleep(1000);
nunchuck_i2c_read(priv, &data[3], 1);
/* Wait */
nxsig_usleep(1000);
nunchuck_i2c_read(priv, &data[4], 1);
/* Wait */
nxsig_usleep(1000);
nunchuck_i2c_read(priv, &data[5], 1);
/* Save the sample */
buffer->js_x = (uint16_t) data[0];
buffer->js_y = (uint16_t) data[1];
buffer->acc_x = (uint16_t) data[2];
buffer->acc_y = (uint16_t) data[3];
buffer->acc_z = (uint16_t) data[4];
buffer->nck_buttons = (uint8_t) ((data[5] + 1) & 0x03);
iinfo("X: %03d | Y: %03d | AX: %03d AY: %03d AZ: %03d | B: %d\n",
data[0], data[1], data[2], data[3],
data[4], ((data[5] + 1) & 0x03));
return OK;
}
/****************************************************************************
* Name: nunchuck_open
****************************************************************************/
static int nunchuck_open(FAR struct file *filep)
{
FAR struct inode *inode;
FAR struct nunchuck_dev_s *priv;
FAR struct nunchuck_open_s *opriv;
int ret;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Get exclusive access to the driver structure */
ret = nxmutex_lock(&priv->lock);
if (ret < 0)
{
ierr("ERROR: nxmutex_lock failed: %d\n", ret);
return ret;
}
/* Allocate a new open structure */
opriv = (FAR struct nunchuck_open_s *)
kmm_zalloc(sizeof(struct nunchuck_open_s));
if (!opriv)
{
ierr("ERROR: Failed to allocate open structure\n");
ret = -ENOMEM;
goto errout_with_lock;
}
/* Attach the open structure to the device */
opriv->nck_flink = priv->nck_open;
priv->nck_open = opriv;
/* Attach the open structure to the file structure */
filep->f_priv = (FAR void *)opriv;
ret = OK;
errout_with_lock:
nxmutex_unlock(&priv->lock);
return ret;
}
/****************************************************************************
* Name: nunchuck_close
****************************************************************************/
static int nunchuck_close(FAR struct file *filep)
{
FAR struct inode *inode;
FAR struct nunchuck_dev_s *priv;
FAR struct nunchuck_open_s *opriv;
FAR struct nunchuck_open_s *curr;
FAR struct nunchuck_open_s *prev;
irqstate_t flags;
bool closing;
int ret;
DEBUGASSERT(filep->f_priv);
opriv = filep->f_priv;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Handle an improbable race conditions with the following atomic test
* and set.
*
* This is actually a pretty feeble attempt to handle this. The
* improbable race condition occurs if two different threads try to
* close the joystick driver at the same time. The rule: don't do
* that! It is feeble because we do not really enforce stale pointer
* detection anyway.
*/
flags = enter_critical_section();
closing = opriv->nck_closing;
opriv->nck_closing = true;
leave_critical_section(flags);
if (closing)
{
/* Another thread is doing the close */
return OK;
}
/* Get exclusive access to the driver structure */
ret = nxmutex_lock(&priv->lock);
if (ret < 0)
{
ierr("ERROR: nxmutex_lock failed: %d\n", ret);
return ret;
}
/* Find the open structure in the list of open structures for the device */
for (prev = NULL, curr = priv->nck_open;
curr && curr != opriv;
prev = curr, curr = curr->nck_flink);
DEBUGASSERT(curr);
if (!curr)
{
ierr("ERROR: Failed to find open entry\n");
ret = -ENOENT;
goto errout_with_lock;
}
/* Remove the structure from the device */
if (prev)
{
prev->nck_flink = opriv->nck_flink;
}
else
{
priv->nck_open = opriv->nck_flink;
}
/* And free the open structure */
kmm_free(opriv);
ret = OK;
errout_with_lock:
nxmutex_unlock(&priv->lock);
return ret;
}
/****************************************************************************
* Name: nunchuck_read
****************************************************************************/
static ssize_t nunchuck_read(FAR struct file *filep, FAR char *buffer,
size_t len)
{
FAR struct inode *inode;
FAR struct nunchuck_dev_s *priv;
int ret;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Make sure that the buffer is sufficiently large to hold at least one
* complete sample.
*
* REVISIT: Should also check buffer alignment.
*/
if (len < sizeof(struct nunchuck_sample_s))
{
ierr("ERROR: buffer too small: %lu\n", (unsigned long)len);
return -EINVAL;
}
/* Get exclusive access to the driver structure */
ret = nxmutex_lock(&priv->lock);
if (ret < 0)
{
ierr("ERROR: nxmutex_lock failed: %d\n", ret);
return ret;
}
/* Read and return the current state of the joystick buttons */
ret = nunchuck_sample(priv, (FAR struct nunchuck_sample_s *)buffer);
if (ret >= 0)
{
ret = sizeof(struct nunchuck_sample_s);
}
nxmutex_unlock(&priv->lock);
return (ssize_t)ret;
}
/****************************************************************************
* Name: nunchuck_ioctl
****************************************************************************/
static int nunchuck_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode;
FAR struct nunchuck_dev_s *priv;
int ret;
DEBUGASSERT(filep->f_priv);
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Get exclusive access to the driver structure */
ret = nxmutex_lock(&priv->lock);
if (ret < 0)
{
ierr("ERROR: nxmutex_lock failed: %d\n", ret);
return ret;
}
/* Handle the ioctl command */
ret = -EINVAL;
switch (cmd)
{
/* Command: NUNCHUCKIOC_SUPPORTED
* Description: Report the set of button events supported by the
* hardware;
* Argument: A pointer to writeable integer value in which to
* return the set of supported buttons.
* Return: Zero (OK) on success. Minus one will be returned
* on failure with the errno value set appropriately.
*/
case NUNCHUCKIOC_SUPPORTED:
{
FAR int *supported = (FAR int *)((uintptr_t)arg);
if (supported)
{
*supported = (NUNCHUCK_BUTTON_Z_BIT | NUNCHUCK_BUTTON_C_BIT);
ret = OK;
}
}
break;
default:
ierr("ERROR: Unrecognized command: %ld\n", cmd);
ret = -ENOTTY;
break;
}
nxmutex_unlock(&priv->lock);
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nunchuck_register
*
* Description:
* Register the Nunchuck character driver as the specified device.
*
* Input Parameters:
* devname - The name of the Nunchuck joystick device to be registered.
* This should be a string of the form "/dev/nunchuckN" where N is the
* minor device number.
* i2c - An instance of the platform-specific I2C connected to Nunchuck.
*
* Returned Value:
* Zero (OK) is returned on success. Otherwise a negated errno value is
* returned to indicate the nature of the failure.
*
****************************************************************************/
int nunchuck_register(FAR const char *devname, FAR struct i2c_master_s *i2c)
{
FAR struct nunchuck_dev_s *priv;
int ret;
iinfo("Enter\n");
DEBUGASSERT(devname && i2c);
/* Allocate a new nunchuck driver instance */
priv = (FAR struct nunchuck_dev_s *)
kmm_zalloc(sizeof(struct nunchuck_dev_s));
if (!priv)
{
ierr("ERROR: Failed to allocate device structure\n");
return -ENOMEM;
}
/* Save the i2c device */
priv->i2c_dev = i2c;
/* Initialize the new nunchuck driver instance */
nxmutex_init(&priv->nck_lock);
/* And register the nunchuck driver */
ret = register_driver(devname, &g_nunchuck_fops, 0666, priv);
if (ret < 0)
{
ierr("ERROR: register_driver failed: %d\n", ret);
goto errout_with_priv;
}
return OK;
errout_with_priv:
nxmutex_destroy(&priv->nck_lock);
kmm_free(priv);
return ret;
}
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