drivers/gpio/gpio-pcf857x.c

File Facts

System

Linux kernel

Corpus path

drivers/gpio/gpio-pcf857x.c

Extension

.c

Size

13059 bytes

Lines

472

Domain

Driver Families

Bucket

drivers/gpio

Inferred role

Driver Families: exported/initcall integration point

Status

integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

• Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.
• Exports symbols or registers init work; inspect boot/module ordering and who consumes the exported contract.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Touches IRQ or DMA behavior; this matters for the representative real-device path.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/delay.h
• linux/gpio/consumer.h
• linux/gpio/driver.h
• linux/i2c.h
• linux/interrupt.h
• linux/irq.h
• linux/irqdomain.h
• linux/kernel.h
• linux/mod_devicetable.h
• linux/module.h
• linux/property.h
• linux/slab.h
• linux/spinlock.h

Detected Declarations

• struct pcf857x
• function i2c_write_le8
• function i2c_read_le8
• function i2c_write_le16
• function i2c_read_le16
• function pcf857x_input
• function pcf857x_get
• function pcf857x_get_multiple
• function pcf857x_output
• function pcf857x_set
• function pcf857x_set_multiple
• function pcf857x_irq
• function noop
• function pcf857x_irq_enable
• function pcf857x_irq_disable
• function pcf857x_irq_bus_lock
• function pcf857x_irq_bus_sync_unlock
• function pcf857x_probe
• function pcf857x_shutdown
• function pcf857x_init
• function pcf857x_exit
• module init pcf857x_init

Annotated Snippet

subsys_initcall(pcf857x_init);

static void __exit pcf857x_exit(void)
{
	i2c_del_driver(&pcf857x_driver);
}
module_exit(pcf857x_exit);

MODULE_DESCRIPTION("Driver for pcf857x, pca857x, and pca967x I2C GPIO expanders");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Brownell");

Annotation

• Immediate include surface: `linux/delay.h`, `linux/gpio/consumer.h`, `linux/gpio/driver.h`, `linux/i2c.h`, `linux/interrupt.h`, `linux/irq.h`, `linux/irqdomain.h`, `linux/kernel.h`.
• Detected declarations: `struct pcf857x`, `function i2c_write_le8`, `function i2c_read_le8`, `function i2c_write_le16`, `function i2c_read_le16`, `function pcf857x_input`, `function pcf857x_get`, `function pcf857x_get_multiple`, `function pcf857x_output`, `function pcf857x_set`.
• Atlas domain: Driver Families / drivers/gpio.
• Implementation status: integration implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.
• IRQ or DMA behavior appears here, which is relevant to the selected PCIe/NVMe device path.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.