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// 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 <ds@schleef.org>
*/
/*
* 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 {
unsigned long regbase;
int (*io)(struct comedi_device *dev, int dir, int port, int data,
unsigned long regbase);
};
static int subdev_8255_io(struct comedi_device *dev,
int dir, int port, int data, unsigned long regbase)
{
if (dir) {
outb(data, dev->iobase + regbase + port);
return 0;
}
return inb(dev->iobase + regbase + port);
}
static int subdev_8255_mmio(struct comedi_device *dev,
int dir, int port, int data, unsigned long regbase)
{
if (dir) {
writeb(data, dev->mmio + regbase + port);
return 0;
}
return readb(dev->mmio + regbase + port);
}
static int subdev_8255_insn(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
unsigned int *data)
{
struct subdev_8255_private *spriv = s->private;
unsigned long regbase = spriv->regbase;
unsigned int mask;
unsigned int v;
mask = comedi_dio_update_state(s, data);
if (mask) {
if (mask & 0xff)
spriv->io(dev, 1, I8255_DATA_A_REG,
s->state & 0xff, regbase);
if (mask & 0xff00)
spriv->io(dev, 1, I8255_DATA_B_REG,
(s->state >> 8) & 0xff, regbase);
if (mask & 0xff0000)
spriv->io(dev, 1, I8255_DATA_C_REG,
(s->state >> 16) & 0xff, regbase);
}
v = spriv->io(dev, 0, I8255_DATA_A_REG, 0, regbase);
v |= (spriv->io(dev, 0, I8255_DATA_B_REG, 0, regbase) << 8);
v |= (spriv->io(dev, 0, I8255_DATA_C_REG, 0, regbase) << 16);
data[1] = v;
return insn->n;
}
static void subdev_8255_do_config(struct comedi_device *dev,
struct comedi_subdevice *s)
{
struct subdev_8255_private *spriv = s->private;
unsigned long regbase = spriv->regbase;
int config;
config = I8255_CTRL_CW;
/* 1 in io_bits indicates output, 1 in config indicates input */
if (!(s->io_bits & 0x0000ff))
config |= I8255_CTRL_A_IO;
if (!(s->io_bits & 0x00ff00))
config |= I8255_CTRL_B_IO;
if (!(s->io_bits & 0x0f0000))
config |= I8255_CTRL_C_LO_IO;
if (!(s->io_bits & 0xf00000))
config |= I8255_CTRL_C_HI_IO;
spriv->io(dev, 1, I8255_CTRL_REG, config, regbase);
}
static int subdev_8255_insn_config(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
unsigned int *data)
{
unsigned int chan = CR_CHAN(insn->chanspec);
unsigned int mask;
int ret;
if (chan < 8)
mask = 0x0000ff;
else if (chan < 16)
mask = 0x00ff00;
else if (chan < 20)
mask = 0x0f0000;
else
mask = 0xf00000;
ret = comedi_dio_insn_config(dev, s, insn, data, mask);
if (ret)
return ret;
subdev_8255_do_config(dev, s);
return insn->n;
}
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 regbase),
unsigned long regbase,
bool is_mmio)
{
struct subdev_8255_private *spriv;
spriv = comedi_alloc_spriv(s, sizeof(*spriv));
if (!spriv)
return -ENOMEM;
if (io)
spriv->io = io;
else if (is_mmio)
spriv->io = subdev_8255_mmio;
else
spriv->io = subdev_8255_io;
spriv->regbase = regbase;
s->type = COMEDI_SUBD_DIO;
s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
s->n_chan = 24;
s->range_table = &range_digital;
s->maxdata = 1;
s->insn_bits = subdev_8255_insn;
s->insn_config = subdev_8255_insn_config;
subdev_8255_do_config(dev, s);
return 0;
}
/**
* subdev_8255_init - initialize DIO subdevice for driving I/O mapped 8255
* @dev: comedi device owning subdevice
* @s: comedi subdevice to initialize
* @io: (optional) register I/O call-back function
* @regbase: offset of 8255 registers from dev->iobase, or call-back context
*
* Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip.
*
* If the optional I/O call-back function is provided, its prototype is of
* the following form:
*
* int my_8255_callback(struct comedi_device *dev, int dir, int port,
* int data, unsigned long regbase);
*
* where 'dev', and 'regbase' 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.
*
* If the optional I/O call-back function is not provided, an internal
* call-back function is used which uses consecutive I/O port addresses
* starting at dev->iobase + regbase.
*
* Return: -ENOMEM if failed to allocate memory, zero on success.
*/
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 regbase),
unsigned long regbase)
{
return __subdev_8255_init(dev, s, io, regbase, false);
}
EXPORT_SYMBOL_GPL(subdev_8255_init);
/**
* subdev_8255_mm_init - initialize DIO subdevice for driving mmio-mapped 8255
* @dev: comedi device owning subdevice
* @s: comedi subdevice to initialize
* @io: (optional) register I/O call-back function
* @regbase: offset of 8255 registers from dev->mmio, or call-back context
*
* Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip.
*
* If the optional I/O call-back function is provided, its prototype is of
* the following form:
*
* int my_8255_callback(struct comedi_device *dev, int dir, int port,
* int data, unsigned long regbase);
*
* where 'dev', and 'regbase' 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.
*
* If the optional I/O call-back function is not provided, an internal
* call-back function is used which uses consecutive MMIO virtual addresses
* starting at dev->mmio + regbase.
*
* Return: -ENOMEM if failed to allocate memory, zero on success.
*/
int subdev_8255_mm_init(struct comedi_device *dev, struct comedi_subdevice *s,
int (*io)(struct comedi_device *dev, int dir, int port,
int data, unsigned long regbase),
unsigned long regbase)
{
return __subdev_8255_init(dev, s, io, regbase, true);
}
EXPORT_SYMBOL_GPL(subdev_8255_mm_init);
/**
* subdev_8255_regbase - get offset of 8255 registers or call-back context
* @s: comedi subdevice
*
* Returns the 'regbase' parameter that was previously passed to
* subdev_8255_init() or subdev_8255_mm_init() to set up the subdevice.
* Only valid if the subdevice was set up successfully.
*/
unsigned long subdev_8255_regbase(struct comedi_subdevice *s)
{
struct subdev_8255_private *spriv = s->private;
return spriv->regbase;
}
EXPORT_SYMBOL_GPL(subdev_8255_regbase);
static int __init comedi_8255_module_init(void)
{
return 0;
}
module_init(comedi_8255_module_init);
static void __exit comedi_8255_module_exit(void)
{
}
module_exit(comedi_8255_module_exit);
MODULE_AUTHOR("Comedi https://www.comedi.org");
MODULE_DESCRIPTION("Comedi: Generic 8255 digital I/O support");
MODULE_LICENSE("GPL");
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