// SPDX-License-Identifier: GPL-2.0+ /* * comedi_8255.c * Generic 8255 digital I/O support * * Split from the Comedi "8255" driver module. * * COMEDI - Linux Control and Measurement Device Interface * Copyright (C) 1998 David A. Schleef <[email protected]> */ /* * Module: comedi_8255 * Description: Generic 8255 support * Author: ds * Updated: Fri, 22 May 2015 12:14:17 +0000 * Status: works * * This module is not used directly by end-users. Rather, it is used by * other drivers to provide support for an 8255 "Programmable Peripheral * Interface" (PPI) chip. * * The classic in digital I/O. The 8255 appears in Comedi as a single * digital I/O subdevice with 24 channels. The channel 0 corresponds to * the 8255's port A, bit 0; channel 23 corresponds to port C, bit 7. * Direction configuration is done in blocks, with channels 0-7, 8-15, * 16-19, and 20-23 making up the 4 blocks. The only 8255 mode * supported is mode 0. */ #include <linux/module.h> #include <linux/comedi/comedidev.h> #include <linux/comedi/comedi_8255.h> struct subdev_8255_private { … }; #ifdef CONFIG_HAS_IOPORT static int subdev_8255_io(struct comedi_device *dev, int dir, int port, int data, unsigned long regbase) { … } #endif /* CONFIG_HAS_IOPORT */ static int subdev_8255_mmio(struct comedi_device *dev, int dir, int port, int data, unsigned long regbase) { … } static int subdev_8255_insn(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, unsigned int *data) { … } static void subdev_8255_do_config(struct comedi_device *dev, struct comedi_subdevice *s) { … } static int subdev_8255_insn_config(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, unsigned int *data) { … } static int __subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s, int (*io)(struct comedi_device *dev, int dir, int port, int data, unsigned long context), unsigned long context) { … } #ifdef CONFIG_HAS_IOPORT /** * subdev_8255_io_init - initialize DIO subdevice for driving I/O mapped 8255 * @dev: comedi device owning subdevice * @s: comedi subdevice to initialize * @regbase: offset of 8255 registers from dev->iobase * * Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip. * * Return: -ENOMEM if failed to allocate memory, zero on success. */ int subdev_8255_io_init(struct comedi_device *dev, struct comedi_subdevice *s, unsigned long regbase) { … } EXPORT_SYMBOL_GPL(…); #endif /* CONFIG_HAS_IOPORT */ /** * subdev_8255_mm_init - initialize DIO subdevice for driving mmio-mapped 8255 * @dev: comedi device owning subdevice * @s: comedi subdevice to initialize * @regbase: offset of 8255 registers from dev->mmio * * Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip. * * Return: -ENOMEM if failed to allocate memory, zero on success. */ int subdev_8255_mm_init(struct comedi_device *dev, struct comedi_subdevice *s, unsigned long regbase) { … } EXPORT_SYMBOL_GPL(…); /** * subdev_8255_cb_init - initialize DIO subdevice for driving callback-mapped 8255 * @dev: comedi device owning subdevice * @s: comedi subdevice to initialize * @io: register I/O call-back function * @context: call-back context * * Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip. * * The prototype of the I/O call-back function is of the following form: * * int my_8255_callback(struct comedi_device *dev, int dir, int port, * int data, unsigned long context); * * where 'dev', and 'context' match the values passed to this function, * 'port' is the 8255 port number 0 to 3 (including the control port), 'dir' * is the direction (0 for read, 1 for write) and 'data' is the value to be * written. It should return 0 if writing or the value read if reading. * * * Return: -ENOMEM if failed to allocate memory, zero on success. */ int subdev_8255_cb_init(struct comedi_device *dev, struct comedi_subdevice *s, int (*io)(struct comedi_device *dev, int dir, int port, int data, unsigned long context), unsigned long context) { … } EXPORT_SYMBOL_GPL(…); /** * subdev_8255_regbase - get offset of 8255 registers or call-back context * @s: comedi subdevice * * Returns the 'regbase' or 'context' parameter that was previously passed to * subdev_8255_io_init(), subdev_8255_mm_init(), or subdev_8255_cb_init() to * set up the subdevice. Only valid if the subdevice was set up successfully. */ unsigned long subdev_8255_regbase(struct comedi_subdevice *s) { … } EXPORT_SYMBOL_GPL(…); static int __init comedi_8255_module_init(void) { … } module_init(…) …; static void __exit comedi_8255_module_exit(void) { … } module_exit(comedi_8255_module_exit); MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
Codebase Browser
linux