Linux Device Drivers

Table of Contents

1. Driver Basics

Driver Entry and Exit points

Atomic and pointer manipulation

Delaying, scheduling, and timer routines

Wait queues and Wake events

High-resolution timers

Workqueues and Kevents

Internal Functions

Kernel objects manipulation

Kernel utility functions

Device Resource Management

2. Device drivers infrastructure

The Basic Device Driver-Model Structures

Device Drivers Base

Buffer Sharing and Synchronization

dma-buf

reservation

fence

Device Drivers DMA Management

Device Drivers Power Management

Device Drivers ACPI Support

Device drivers PnP support

Userspace IO devices

3. Parallel Port Devices

parport_yield — relinquish a parallel port temporarily

parport_yield_blocking — relinquish a parallel port temporarily

parport_wait_event — wait for an event on a parallel port

parport_wait_peripheral — wait for status lines to change in 35ms

parport_negotiate — negotiate an IEEE 1284 mode

parport_write — write a block of data to a parallel port

parport_read — read a block of data from a parallel port

parport_set_timeout — set the inactivity timeout for a device

__parport_register_driver — register a parallel port device driver

parport_unregister_driver — deregister a parallel port device driver

parport_get_port — increment a port's reference count

parport_put_port — decrement a port's reference count

parport_register_port — register a parallel port

parport_announce_port — tell device drivers about a parallel port

parport_remove_port — deregister a parallel port

parport_register_device — register a device on a parallel port

parport_unregister_device — deregister a device on a parallel port

parport_find_number — find a parallel port by number

parport_find_base — find a parallel port by base address

parport_claim — claim access to a parallel port device

parport_claim_or_block — claim access to a parallel port device

parport_release — give up access to a parallel port device

parport_open — find a device by canonical device number

parport_close close a device opened with parport_open

4. Message-based devices

Fusion message devices

5. Sound Devices

snd_printk — printk wrapper

snd_printd — debug printk

snd_BUG — give a BUG warning message and stack trace

snd_printd_ratelimit —

snd_BUG_ON — debugging check macro

snd_printdd — debug printk

register_sound_special_device — register a special sound node

register_sound_mixer — register a mixer device

register_sound_midi — register a midi device

register_sound_dsp — register a DSP device

unregister_sound_special — unregister a special sound device

unregister_sound_mixer — unregister a mixer

unregister_sound_midi — unregister a midi device

unregister_sound_dsp — unregister a DSP device

snd_pcm_stream_linked — Check whether the substream is linked with others

snd_pcm_stream_lock_irqsave — Lock the PCM stream

snd_pcm_group_for_each_entry — iterate over the linked substreams

snd_pcm_running — Check whether the substream is in a running state

bytes_to_samples — Unit conversion of the size from bytes to samples

bytes_to_frames — Unit conversion of the size from bytes to frames

samples_to_bytes — Unit conversion of the size from samples to bytes

frames_to_bytes — Unit conversion of the size from frames to bytes

frame_aligned — Check whether the byte size is aligned to frames

snd_pcm_lib_buffer_bytes — Get the buffer size of the current PCM in bytes

snd_pcm_lib_period_bytes — Get the period size of the current PCM in bytes

snd_pcm_playback_avail — Get the available (writable) space for playback

snd_pcm_capture_avail — Get the available (readable) space for capture

snd_pcm_playback_hw_avail — Get the queued space for playback

snd_pcm_capture_hw_avail — Get the free space for capture

snd_pcm_playback_ready — check whether the playback buffer is available

snd_pcm_capture_ready — check whether the capture buffer is available

snd_pcm_playback_data — check whether any data exists on the playback buffer

snd_pcm_playback_empty — check whether the playback buffer is empty

snd_pcm_capture_empty — check whether the capture buffer is empty

snd_pcm_trigger_done — Mark the master substream

params_channels — Get the number of channels from the hw params

params_rate — Get the sample rate from the hw params

params_period_size — Get the period size (in frames) from the hw params

params_periods — Get the number of periods from the hw params

params_buffer_size — Get the buffer size (in frames) from the hw params

params_buffer_bytes — Get the buffer size (in bytes) from the hw params

snd_pcm_hw_constraint_single — Constrain parameter to a single value

snd_pcm_format_cpu_endian — Check the PCM format is CPU-endian

snd_pcm_set_runtime_buffer — Set the PCM runtime buffer

snd_pcm_gettime — Fill the timespec depending on the timestamp mode

snd_pcm_lib_alloc_vmalloc_buffer — allocate virtual DMA buffer

snd_pcm_lib_alloc_vmalloc_32_buffer — allocate 32-bit-addressable buffer

snd_pcm_sgbuf_get_addr — Get the DMA address at the corresponding offset

snd_pcm_sgbuf_get_ptr — Get the virtual address at the corresponding offset

snd_pcm_sgbuf_get_chunk_size — Compute the max size that fits within the contig. page from the given size

snd_pcm_mmap_data_open — increase the mmap counter

snd_pcm_mmap_data_close — decrease the mmap counter

snd_pcm_limit_isa_dma_size — Get the max size fitting with ISA DMA transfer

snd_pcm_stream_str — Get a string naming the direction of a stream

snd_pcm_chmap_substream — get the PCM substream assigned to the given chmap info

pcm_format_to_bits — Strong-typed conversion of pcm_format to bitwise

snd_pcm_format_name — Return a name string for the given PCM format

snd_pcm_new_stream — create a new PCM stream

snd_pcm_new — create a new PCM instance

snd_pcm_new_internal — create a new internal PCM instance

snd_pcm_notify — Add/remove the notify list

snd_device_new — create an ALSA device component

snd_device_disconnect — disconnect the device

snd_device_free — release the device from the card

snd_device_register — register the device

snd_info_get_line — read one line from the procfs buffer

snd_info_get_str — parse a string token

snd_info_create_module_entry — create an info entry for the given module

snd_info_create_card_entry — create an info entry for the given card

snd_info_free_entry — release the info entry

snd_info_register — register the info entry

snd_rawmidi_receive — receive the input data from the device

snd_rawmidi_transmit_empty — check whether the output buffer is empty

__snd_rawmidi_transmit_peek — copy data from the internal buffer

snd_rawmidi_transmit_peek — copy data from the internal buffer

__snd_rawmidi_transmit_ack — acknowledge the transmission

snd_rawmidi_transmit_ack — acknowledge the transmission

snd_rawmidi_transmit — copy from the buffer to the device

snd_rawmidi_new — create a rawmidi instance

snd_rawmidi_set_ops — set the rawmidi operators

snd_request_card — try to load the card module

snd_lookup_minor_data — get user data of a registered device

snd_register_device — Register the ALSA device file for the card

snd_unregister_device — unregister the device on the given card

copy_to_user_fromio — copy data from mmio-space to user-space

copy_from_user_toio — copy data from user-space to mmio-space

snd_pcm_lib_preallocate_free_for_all — release all pre-allocated buffers on the pcm

snd_pcm_lib_preallocate_pages — pre-allocation for the given DMA type

snd_pcm_lib_preallocate_pages_for_all — pre-allocation for continuous memory type (all substreams)

snd_pcm_sgbuf_ops_page — get the page struct at the given offset

snd_pcm_lib_malloc_pages — allocate the DMA buffer

snd_pcm_lib_free_pages — release the allocated DMA buffer.

snd_pcm_lib_free_vmalloc_buffer — free vmalloc buffer

snd_pcm_lib_get_vmalloc_page — map vmalloc buffer offset to page struct

snd_device_initialize — Initialize struct device for sound devices

snd_card_new — create and initialize a soundcard structure

snd_card_disconnect — disconnect all APIs from the file-operations (user space)

snd_card_free_when_closed — Disconnect the card, free it later eventually

snd_card_free — frees given soundcard structure

snd_card_set_id — set card identification name

snd_card_add_dev_attr — Append a new sysfs attribute group to card

snd_card_register — register the soundcard

snd_component_add — add a component string

snd_card_file_add — add the file to the file list of the card

snd_card_file_remove — remove the file from the file list

snd_power_wait — wait until the power-state is changed.

snd_dma_program — program an ISA DMA transfer

snd_dma_disable — stop the ISA DMA transfer

snd_dma_pointer — return the current pointer to DMA transfer buffer in bytes

snd_ctl_notify — Send notification to user-space for a control change

snd_ctl_new1 — create a control instance from the template

snd_ctl_free_one — release the control instance

snd_ctl_add — add the control instance to the card

snd_ctl_replace — replace the control instance of the card

snd_ctl_remove — remove the control from the card and release it

snd_ctl_remove_id — remove the control of the given id and release it

snd_ctl_activate_id — activate/inactivate the control of the given id

snd_ctl_rename_id — replace the id of a control on the card

snd_ctl_find_numid — find the control instance with the given number-id

snd_ctl_find_id — find the control instance with the given id

snd_ctl_register_ioctl — register the device-specific control-ioctls

snd_ctl_register_ioctl_compat — register the device-specific 32bit compat control-ioctls

snd_ctl_unregister_ioctl — de-register the device-specific control-ioctls

snd_ctl_unregister_ioctl_compat — de-register the device-specific compat 32bit control-ioctls

snd_ctl_boolean_mono_info — Helper function for a standard boolean info callback with a mono channel

snd_ctl_boolean_stereo_info — Helper function for a standard boolean info callback with stereo two channels

snd_ctl_enum_info — fills the info structure for an enumerated control

snd_pcm_set_ops — set the PCM operators

snd_pcm_set_sync — set the PCM sync id

snd_interval_refine — refine the interval value of configurator

snd_interval_ratnum — refine the interval value

snd_interval_list — refine the interval value from the list

snd_interval_ranges — refine the interval value from the list of ranges

snd_pcm_hw_rule_add — add the hw-constraint rule

snd_pcm_hw_constraint_mask64 — apply the given bitmap mask constraint

snd_pcm_hw_constraint_integer — apply an integer constraint to an interval

snd_pcm_hw_constraint_minmax — apply a min/max range constraint to an interval

snd_pcm_hw_constraint_list — apply a list of constraints to a parameter

snd_pcm_hw_constraint_ranges — apply list of range constraints to a parameter

snd_pcm_hw_constraint_ratnums — apply ratnums constraint to a parameter

snd_pcm_hw_constraint_ratdens — apply ratdens constraint to a parameter

snd_pcm_hw_constraint_msbits — add a hw constraint msbits rule

snd_pcm_hw_constraint_step — add a hw constraint step rule

snd_pcm_hw_constraint_pow2 — add a hw constraint power-of-2 rule

snd_pcm_hw_rule_noresample — add a rule to allow disabling hw resampling

snd_pcm_hw_param_value — return params field var value

snd_pcm_hw_param_first — refine config space and return minimum value

snd_pcm_hw_param_last — refine config space and return maximum value

snd_pcm_lib_ioctl — a generic PCM ioctl callback

snd_pcm_period_elapsed — update the pcm status for the next period

snd_pcm_add_chmap_ctls — create channel-mapping control elements

snd_hwdep_new — create a new hwdep instance

snd_pcm_stream_lock — Lock the PCM stream

snd_pcm_stream_unlock — Unlock the PCM stream

snd_pcm_stream_lock_irq — Lock the PCM stream

snd_pcm_stream_unlock_irq — Unlock the PCM stream

snd_pcm_stream_unlock_irqrestore — Unlock the PCM stream

snd_pcm_stop — try to stop all running streams in the substream group

snd_pcm_stop_xrun — stop the running streams as XRUN

snd_pcm_suspend — trigger SUSPEND to all linked streams

snd_pcm_suspend_all — trigger SUSPEND to all substreams in the given pcm

snd_pcm_lib_default_mmap — Default PCM data mmap function

snd_pcm_lib_mmap_iomem — Default PCM data mmap function for I/O mem

snd_malloc_pages — allocate pages with the given size

snd_free_pages — release the pages

snd_dma_alloc_pages — allocate the buffer area according to the given type

snd_dma_alloc_pages_fallback — allocate the buffer area according to the given type with fallback

snd_dma_free_pages — release the allocated buffer

6. Media Devices

Video2Linux devices

Digital TV (DVB) devices

Remote Controller devices

Media Controller devices

Consumer Electronics Control devices

7. 16x50 UART Driver

uart_update_timeout — update per-port FIFO timeout.

uart_get_baud_rate — return baud rate for a particular port

uart_get_divisor — return uart clock divisor

uart_console_write — write a console message to a serial port

uart_parse_earlycon — Parse earlycon options

uart_parse_options — Parse serial port baud/parity/bits/flow control.

uart_set_options — setup the serial console parameters

uart_register_driver — register a driver with the uart core layer

uart_unregister_driver — remove a driver from the uart core layer

uart_add_one_port — attach a driver-defined port structure

uart_remove_one_port — detach a driver defined port structure

uart_handle_dcd_change — handle a change of carrier detect state

uart_handle_cts_change — handle a change of clear-to-send state

uart_insert_char — push a char to the uart layer

serial8250_get_port — retrieve struct uart_8250_port

serial8250_suspend_port — suspend one serial port

serial8250_resume_port — resume one serial port

serial8250_register_8250_port — register a serial port

serial8250_unregister_port — remove a 16x50 serial port at runtime

8. Frame Buffer Library

Frame Buffer Memory

Frame Buffer Colormap

Frame Buffer Video Mode Database

Frame Buffer Macintosh Video Mode Database

Frame Buffer Fonts

9. Input Subsystem

Input core

Multitouch Library

Polled input devices

Matrix keyboards/keypads

Sparse keymap support

10. Serial Peripheral Interface (SPI)

struct spi_statistics — statistics for spi transfers

struct spi_device — Master side proxy for an SPI slave device

struct spi_driver — Host side “protocol” driver

spi_unregister_driver — reverse effect of spi_register_driver

module_spi_driver — Helper macro for registering a SPI driver

struct spi_master — interface to SPI master controller

struct spi_res — spi resource management structure

struct spi_transfer — a read/write buffer pair

struct spi_message — one multi-segment SPI transaction

spi_message_init_with_transfers — Initialize spi_message and append transfers

struct spi_replaced_transfers — structure describing the spi_transfer replacements that have occurred so that they can get reverted

spi_write — SPI synchronous write

spi_read — SPI synchronous read

spi_sync_transfer — synchronous SPI data transfer

spi_w8r8 — SPI synchronous 8 bit write followed by 8 bit read

spi_w8r16 — SPI synchronous 8 bit write followed by 16 bit read

spi_w8r16be — SPI synchronous 8 bit write followed by 16 bit big-endian read

struct spi_flash_read_message — flash specific information for spi-masters that provide accelerated flash read interfaces

struct spi_board_info — board-specific template for a SPI device

spi_register_board_info — register SPI devices for a given board

__spi_register_driver — register a SPI driver

spi_alloc_device — Allocate a new SPI device

spi_add_device — Add spi_device allocated with spi_alloc_device

spi_new_device — instantiate one new SPI device

spi_unregister_device — unregister a single SPI device

spi_finalize_current_transfer — report completion of a transfer

spi_get_next_queued_message — called by driver to check for queued messages

spi_finalize_current_message — the current message is complete

spi_alloc_master — allocate SPI master controller

spi_register_master — register SPI master controller

devm_spi_register_master — register managed SPI master controller

spi_unregister_master — unregister SPI master controller

spi_busnum_to_master — look up master associated with bus_num

spi_res_alloc — allocate a spi resource that is life-cycle managed during the processing of a spi_message while using spi_transfer_one

spi_res_free — free an spi resource

spi_res_add — add a spi_res to the spi_message

spi_res_release — release all spi resources for this message

spi_replace_transfers — replace transfers with several transfers and register change with spi_message.resources

spi_split_transfers_maxsize — split spi transfers into multiple transfers when an individual transfer exceeds a certain size

spi_setup — setup SPI mode and clock rate

spi_async — asynchronous SPI transfer

spi_async_locked — version of spi_async with exclusive bus usage

spi_sync — blocking/synchronous SPI data transfers

spi_sync_locked — version of spi_sync with exclusive bus usage

spi_bus_lock — obtain a lock for exclusive SPI bus usage

spi_bus_unlock — release the lock for exclusive SPI bus usage

spi_write_then_read — SPI synchronous write followed by read

11. I²C and SMBus Subsystem

struct i2c_driver — represent an I2C device driver

struct i2c_client — represent an I2C slave device

struct i2c_board_info — template for device creation

I2C_BOARD_INFO — macro used to list an i2c device and its address

struct i2c_algorithm — represent I2C transfer method

struct i2c_timings — I2C timing information

struct i2c_bus_recovery_info — I2C bus recovery information

struct i2c_adapter_quirks — describe flaws of an i2c adapter

i2c_lock_bus — Get exclusive access to an I2C bus segment

i2c_unlock_bus — Release exclusive access to an I2C bus segment

i2c_check_quirks — Function for checking the quirk flags in an i2c adapter

module_i2c_driver — Helper macro for registering a modular I2C driver

builtin_i2c_driver — Helper macro for registering a builtin I2C driver

i2c_register_board_info — statically declare I2C devices

i2c_verify_client — return parameter as i2c_client, or NULL

i2c_new_device — instantiate an i2c device

i2c_unregister_device reverse effect of i2c_new_device

i2c_new_dummy — return a new i2c device bound to a dummy driver

i2c_verify_adapter — return parameter as i2c_adapter or NULL

i2c_add_adapter — declare i2c adapter, use dynamic bus number

i2c_add_numbered_adapter — declare i2c adapter, use static bus number

i2c_del_adapter — unregister I2C adapter

i2c_parse_fw_timings — get I2C related timing parameters from firmware

i2c_del_driver — unregister I2C driver

i2c_use_client — increments the reference count of the i2c client structure

i2c_release_client — release a use of the i2c client structure

__i2c_transfer — unlocked flavor of i2c_transfer

i2c_transfer — execute a single or combined I2C message

i2c_master_send — issue a single I2C message in master transmit mode

i2c_master_recv — issue a single I2C message in master receive mode

i2c_smbus_read_byte — SMBus “receive byte” protocol

i2c_smbus_write_byte — SMBus “send byte” protocol

i2c_smbus_read_byte_data — SMBus “read byte” protocol

i2c_smbus_write_byte_data — SMBus “write byte” protocol

i2c_smbus_read_word_data — SMBus “read word” protocol

i2c_smbus_write_word_data — SMBus “write word” protocol

i2c_smbus_read_block_data — SMBus “block read” protocol

i2c_smbus_write_block_data — SMBus “block write” protocol

i2c_smbus_xfer — execute SMBus protocol operations

i2c_smbus_read_i2c_block_data_or_emulated — read block or emulate

12. High Speed Synchronous Serial Interface (HSI)

struct hsi_channel — channel resource used by the hsi clients

struct hsi_config — Configuration for RX/TX HSI modules

struct hsi_board_info — HSI client board info

struct hsi_client — HSI client attached to an HSI port

struct hsi_client_driver — Driver associated to an HSI client

struct hsi_msg — HSI message descriptor

struct hsi_port — HSI port device

struct hsi_controller — HSI controller device

hsi_id — Get HSI controller ID associated to a client

hsi_port_id — Gets the port number a client is attached to

hsi_setup — Configure the client's port

hsi_flush — Flush all pending transactions on the client's port

hsi_async_read — Submit a read transfer

hsi_async_write — Submit a write transfer

hsi_start_tx — Signal the port that the client wants to start a TX

hsi_stop_tx — Signal the port that the client no longer wants to transmit

hsi_port_unregister_clients — Unregister an HSI port

hsi_unregister_controller — Unregister an HSI controller

hsi_register_controller — Register an HSI controller and its ports

hsi_register_client_driver — Register an HSI client to the HSI bus

hsi_put_controller — Free an HSI controller

hsi_alloc_controller — Allocate an HSI controller and its ports

hsi_free_msg — Free an HSI message

hsi_alloc_msg — Allocate an HSI message

hsi_async — Submit an HSI transfer to the controller

hsi_claim_port — Claim the HSI client's port

hsi_release_port — Release the HSI client's port

hsi_register_port_event — Register a client to receive port events

hsi_unregister_port_event — Stop receiving port events for a client

hsi_event — Notifies clients about port events

hsi_get_channel_id_by_name — acquire channel id by channel name

13. Pulse-Width Modulation (PWM)

enum pwm_polarity — polarity of a PWM signal

struct pwm_args — board-dependent PWM arguments

struct pwm_device — PWM channel object

pwm_get_state — retrieve the current PWM state

struct pwm_ops — PWM controller operations

struct pwm_chip — abstract a PWM controller

pwm_config — change a PWM device configuration

pwm_set_polarity — configure the polarity of a PWM signal

pwm_enable — start a PWM output toggling

pwm_disable — stop a PWM output toggling

pwm_set_chip_data — set private chip data for a PWM

pwm_get_chip_data — get private chip data for a PWM

pwmchip_add_with_polarity — register a new PWM chip

pwmchip_add — register a new PWM chip

pwmchip_remove — remove a PWM chip

pwm_request — request a PWM device

pwm_request_from_chip — request a PWM device relative to a PWM chip

pwm_free — free a PWM device

pwm_apply_state — atomically apply a new state to a PWM device

pwm_adjust_config — adjust the current PWM config to the PWM arguments

of_pwm_get — request a PWM via the PWM framework

pwm_get — look up and request a PWM device

pwm_put — release a PWM device

devm_pwm_get resource managed pwm_get

devm_of_pwm_get resource managed of_pwm_get

devm_pwm_put resource managed pwm_put

pwm_can_sleep — report whether PWM access will sleep