8. Remote Controller devices

8.1. Remote Controller core

enum rc_driver_type

type of the RC output

Constants

RC_DRIVER_SCANCODE

Driver or hardware generates a scancode

RC_DRIVER_IR_RAW

Driver or hardware generates pulse/space sequences. It needs a Infra-Red pulse/space decoder

struct rc_scancode_filter

Filter scan codes.

Definition

struct rc_scancode_filter {
  u32 data;
  u32 mask;
};

Members

u32 data

Scancode data to match.

u32 mask

Mask of bits of scancode to compare.

enum rc_filter_type

Filter type constants.

Constants

RC_FILTER_NORMAL

Filter for normal operation.

RC_FILTER_WAKEUP

Filter for waking from suspend.

RC_FILTER_MAX

Number of filter types.

struct rc_dev

represents a remote control device

Definition

struct rc_dev {
  struct device dev;
  atomic_t initialized;
  const struct attribute_group * sysfs_groups[5];
  const char * input_name;
  const char * input_phys;
  struct input_id input_id;
  char * driver_name;
  const char * map_name;
  struct rc_map rc_map;
  struct mutex lock;
  unsigned int minor;
  struct ir_raw_event_ctrl * raw;
  struct input_dev * input_dev;
  enum rc_driver_type driver_type;
  bool idle;
  u64 allowed_protocols;
  u64 enabled_protocols;
  u64 allowed_wakeup_protocols;
  u64 enabled_wakeup_protocols;
  struct rc_scancode_filter scancode_filter;
  struct rc_scancode_filter scancode_wakeup_filter;
  u32 scancode_mask;
  u32 users;
  void * priv;
  spinlock_t keylock;
  bool keypressed;
  unsigned long keyup_jiffies;
  struct timer_list timer_keyup;
  u32 last_keycode;
  enum rc_type last_protocol;
  u32 last_scancode;
  u8 last_toggle;
  u32 timeout;
  u32 min_timeout;
  u32 max_timeout;
  u32 rx_resolution;
  u32 tx_resolution;
  int (* change_protocol) (struct rc_dev *dev, u64 *rc_type);
  int (* change_wakeup_protocol) (struct rc_dev *dev, u64 *rc_type);
  int (* open) (struct rc_dev *dev);
  void (* close) (struct rc_dev *dev);
  int (* s_tx_mask) (struct rc_dev *dev, u32 mask);
  int (* s_tx_carrier) (struct rc_dev *dev, u32 carrier);
  int (* s_tx_duty_cycle) (struct rc_dev *dev, u32 duty_cycle);
  int (* s_rx_carrier_range) (struct rc_dev *dev, u32 min, u32 max);
  int (* tx_ir) (struct rc_dev *dev, unsigned *txbuf, unsigned n);
  void (* s_idle) (struct rc_dev *dev, bool enable);
  int (* s_learning_mode) (struct rc_dev *dev, int enable);
  int (* s_carrier_report) (struct rc_dev *dev, int enable);
  int (* s_filter) (struct rc_dev *dev,struct rc_scancode_filter *filter);
  int (* s_wakeup_filter) (struct rc_dev *dev,struct rc_scancode_filter *filter);
  int (* s_timeout) (struct rc_dev *dev,unsigned int timeout);
};

Members

struct device dev

driver model’s view of this device

atomic_t initialized

1 if the device init has completed, 0 otherwise

const struct attribute_group * sysfs_groups[5]

sysfs attribute groups

const char * input_name

name of the input child device

const char * input_phys

physical path to the input child device

struct input_id input_id

id of the input child device (struct input_id)

char * driver_name

name of the hardware driver which registered this device

const char * map_name

name of the default keymap

struct rc_map rc_map

current scan/key table

struct mutex lock

used to ensure we’ve filled in all protocol details before anyone can call show_protocols or store_protocols

unsigned int minor

unique minor remote control device number

struct ir_raw_event_ctrl * raw

additional data for raw pulse/space devices

struct input_dev * input_dev

the input child device used to communicate events to userspace

enum rc_driver_type driver_type

specifies if protocol decoding is done in hardware or software

bool idle

used to keep track of RX state

u64 allowed_protocols

bitmask with the supported RC_BIT_* protocols

u64 enabled_protocols

bitmask with the enabled RC_BIT_* protocols

u64 allowed_wakeup_protocols

bitmask with the supported RC_BIT_* wakeup protocols

u64 enabled_wakeup_protocols

bitmask with the enabled RC_BIT_* wakeup protocols

struct rc_scancode_filter scancode_filter

scancode filter

struct rc_scancode_filter scancode_wakeup_filter

scancode wakeup filters

u32 scancode_mask

some hardware decoders are not capable of providing the full scancode to the application. As this is a hardware limit, we can’t do anything with it. Yet, as the same keycode table can be used with other devices, a mask is provided to allow its usage. Drivers should generally leave this field in blank

u32 users

number of current users of the device

void * priv

driver-specific data

spinlock_t keylock

protects the remaining members of the struct

bool keypressed

whether a key is currently pressed

unsigned long keyup_jiffies

time (in jiffies) when the current keypress should be released

struct timer_list timer_keyup

timer for releasing a keypress

u32 last_keycode

keycode of last keypress

enum rc_type last_protocol

protocol of last keypress

u32 last_scancode

scancode of last keypress

u8 last_toggle

toggle value of last command

u32 timeout

optional time after which device stops sending data

u32 min_timeout

minimum timeout supported by device

u32 max_timeout

maximum timeout supported by device

u32 rx_resolution

resolution (in ns) of input sampler

u32 tx_resolution

resolution (in ns) of output sampler

int (*)(struct rc_dev *dev, u64 *rc_type) change_protocol

allow changing the protocol used on hardware decoders

int (*)(struct rc_dev *dev, u64 *rc_type) change_wakeup_protocol

allow changing the protocol used for wakeup filtering

int (*)(struct rc_dev *dev) open

callback to allow drivers to enable polling/irq when IR input device is opened.

void (*)(struct rc_dev *dev) close

callback to allow drivers to disable polling/irq when IR input device is opened.

int (*)(struct rc_dev *dev, u32 mask) s_tx_mask

set transmitter mask (for devices with multiple tx outputs)

int (*)(struct rc_dev *dev, u32 carrier) s_tx_carrier

set transmit carrier frequency

int (*)(struct rc_dev *dev, u32 duty_cycle) s_tx_duty_cycle

set transmit duty cycle (0% - 100%)

int (*)(struct rc_dev *dev, u32 min, u32 max) s_rx_carrier_range

inform driver about carrier it is expected to handle

int (*)(struct rc_dev *dev, unsigned *txbuf, unsigned n) tx_ir

transmit IR

void (*)(struct rc_dev *dev, bool enable) s_idle

enable/disable hardware idle mode, upon which, device doesn’t interrupt host until it sees IR pulses

int (*)(struct rc_dev *dev, int enable) s_learning_mode

enable wide band receiver used for learning

int (*) (struct rc_dev *dev, int enable) s_carrier_report

enable carrier reports

int (*)(struct rc_dev *dev,struct rc_scancode_filter *filter) s_filter

set the scancode filter

int (*)(struct rc_dev *dev,struct rc_scancode_filter *filter) s_wakeup_filter

set the wakeup scancode filter

int (*)(struct rc_dev *dev,unsigned int timeout) s_timeout

set hardware timeout in ns

struct rc_dev * rc_allocate_device(void)

Allocates a RC device

Parameters

void

no arguments

Description

returns a pointer to struct rc_dev.

void rc_free_device(struct rc_dev * dev)

Frees a RC device

Parameters

struct rc_dev * dev

pointer to struct rc_dev.

int rc_register_device(struct rc_dev * dev)

Registers a RC device

Parameters

struct rc_dev * dev

pointer to struct rc_dev.

void rc_unregister_device(struct rc_dev * dev)

Unregisters a RC device

Parameters

struct rc_dev * dev

pointer to struct rc_dev.

int rc_open(struct rc_dev * rdev)

Opens a RC device

Parameters

struct rc_dev * rdev

pointer to struct rc_dev.

void rc_close(struct rc_dev * rdev)

Closes a RC device

Parameters

struct rc_dev * rdev

pointer to struct rc_dev.

int rc_map_register(struct rc_map_list * map)

Registers a Remote Controler scancode map

Parameters

struct rc_map_list * map

pointer to struct rc_map_list

void rc_map_unregister(struct rc_map_list * map)

Unregisters a Remote Controler scancode map

Parameters

struct rc_map_list * map

pointer to struct rc_map_list

struct rc_map * rc_map_get(const char * name)

gets an RC map from its name

Parameters

const char * name

name of the RC scancode map

8.2. LIRC

struct lirc_driver

Defines the parameters on a LIRC driver

Definition

struct lirc_driver {
  char name[40];
  int minor;
  __u32 code_length;
  unsigned int buffer_size;
  int sample_rate;
  __u32 features;
  unsigned int chunk_size;
  void * data;
  int min_timeout;
  int max_timeout;
  int (* add_to_buf) (void *data, struct lirc_buffer *buf);
  struct lirc_buffer * rbuf;
  int (* set_use_inc) (void *data);
  void (* set_use_dec) (void *data);
  struct rc_dev * rdev;
  const struct file_operations * fops;
  struct device * dev;
  struct module * owner;
};

Members

char name[40]

this string will be used for logs

int minor

indicates minor device (/dev/lirc) number for registered driver if caller fills it with negative value, then the first free minor number will be used (if available).

__u32 code_length

length of the remote control key code expressed in bits.

unsigned int buffer_size

Number of FIFO buffers with chunk_size size. If zero, creates a buffer with BUFLEN size (16 bytes).

int sample_rate

if zero, the device will wait for an event with a new code to be parsed. Otherwise, specifies the sample rate for polling. Value should be between 0 and HZ. If equal to HZ, it would mean one polling per second.

__u32 features

lirc compatible hardware features, like LIRC_MODE_RAW, LIRC_CAN_*, as defined at include/media/lirc.h.

unsigned int chunk_size

Size of each FIFO buffer.

void * data

it may point to any driver data and this pointer will be passed to all callback functions.

int min_timeout

Minimum timeout for record. Valid only if LIRC_CAN_SET_REC_TIMEOUT is defined.

int max_timeout

Maximum timeout for record. Valid only if LIRC_CAN_SET_REC_TIMEOUT is defined.

int (*)(void *data, struct lirc_buffer *buf) add_to_buf

add_to_buf will be called after specified period of the time or triggered by the external event, this behavior depends on value of the sample_rate this function will be called in user context. This routine should return 0 if data was added to the buffer and -ENODATA if none was available. This should add some number of bits evenly divisible by code_length to the buffer.

struct lirc_buffer * rbuf

if not NULL, it will be used as a read buffer, you will have to write to the buffer by other means, like irq’s (see also lirc_serial.c).

int (*)(void *data) set_use_inc

set_use_inc will be called after device is opened

void (*)(void *data) set_use_dec

set_use_dec will be called after device is closed

struct rc_dev * rdev

Pointed to struct rc_dev associated with the LIRC device.

const struct file_operations * fops

file_operations for drivers which don’t fit the current driver model. Some ioctl’s can be directly handled by lirc_dev if the driver’s ioctl function is NULL or if it returns -ENOIOCTLCMD (see also lirc_serial.c).

struct device * dev

pointer to the struct device associated with the LIRC device.

struct module * owner

the module owning this struct