// SPDX-License-Identifier: GPL-2.0+
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/*
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* comedi_8255.c
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* Generic 8255 digital I/O support
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*
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* Split from the Comedi "8255" driver module.
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*
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* COMEDI - Linux Control and Measurement Device Interface
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* Copyright (C) 1998 David A. Schleef <ds@schleef.org>
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*/
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/*
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* Module: comedi_8255
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* Description: Generic 8255 support
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* Author: ds
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* Updated: Fri, 22 May 2015 12:14:17 +0000
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* Status: works
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*
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* This module is not used directly by end-users. Rather, it is used by
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* other drivers to provide support for an 8255 "Programmable Peripheral
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* Interface" (PPI) chip.
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*
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* The classic in digital I/O. The 8255 appears in Comedi as a single
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* digital I/O subdevice with 24 channels. The channel 0 corresponds to
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* the 8255's port A, bit 0; channel 23 corresponds to port C, bit 7.
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* Direction configuration is done in blocks, with channels 0-7, 8-15,
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* 16-19, and 20-23 making up the 4 blocks. The only 8255 mode
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* supported is mode 0.
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*/
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#include <linux/module.h>
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#include "../comedidev.h"
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#include "8255.h"
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struct subdev_8255_private {
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unsigned long regbase;
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int (*io)(struct comedi_device *dev, int dir, int port, int data,
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unsigned long regbase);
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};
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static int subdev_8255_io(struct comedi_device *dev,
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int dir, int port, int data, unsigned long regbase)
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{
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if (dir) {
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outb(data, dev->iobase + regbase + port);
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return 0;
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}
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return inb(dev->iobase + regbase + port);
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}
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static int subdev_8255_mmio(struct comedi_device *dev,
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int dir, int port, int data, unsigned long regbase)
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{
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if (dir) {
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writeb(data, dev->mmio + regbase + port);
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return 0;
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}
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return readb(dev->mmio + regbase + port);
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}
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static int subdev_8255_insn(struct comedi_device *dev,
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struct comedi_subdevice *s,
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struct comedi_insn *insn,
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unsigned int *data)
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{
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struct subdev_8255_private *spriv = s->private;
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unsigned long regbase = spriv->regbase;
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unsigned int mask;
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unsigned int v;
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mask = comedi_dio_update_state(s, data);
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if (mask) {
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if (mask & 0xff)
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spriv->io(dev, 1, I8255_DATA_A_REG,
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s->state & 0xff, regbase);
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if (mask & 0xff00)
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spriv->io(dev, 1, I8255_DATA_B_REG,
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(s->state >> 8) & 0xff, regbase);
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if (mask & 0xff0000)
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spriv->io(dev, 1, I8255_DATA_C_REG,
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(s->state >> 16) & 0xff, regbase);
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}
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v = spriv->io(dev, 0, I8255_DATA_A_REG, 0, regbase);
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v |= (spriv->io(dev, 0, I8255_DATA_B_REG, 0, regbase) << 8);
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v |= (spriv->io(dev, 0, I8255_DATA_C_REG, 0, regbase) << 16);
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data[1] = v;
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return insn->n;
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}
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static void subdev_8255_do_config(struct comedi_device *dev,
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struct comedi_subdevice *s)
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{
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struct subdev_8255_private *spriv = s->private;
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unsigned long regbase = spriv->regbase;
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int config;
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config = I8255_CTRL_CW;
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/* 1 in io_bits indicates output, 1 in config indicates input */
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if (!(s->io_bits & 0x0000ff))
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config |= I8255_CTRL_A_IO;
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if (!(s->io_bits & 0x00ff00))
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config |= I8255_CTRL_B_IO;
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if (!(s->io_bits & 0x0f0000))
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config |= I8255_CTRL_C_LO_IO;
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if (!(s->io_bits & 0xf00000))
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config |= I8255_CTRL_C_HI_IO;
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spriv->io(dev, 1, I8255_CTRL_REG, config, regbase);
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}
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static int subdev_8255_insn_config(struct comedi_device *dev,
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struct comedi_subdevice *s,
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struct comedi_insn *insn,
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unsigned int *data)
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{
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unsigned int chan = CR_CHAN(insn->chanspec);
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unsigned int mask;
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int ret;
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if (chan < 8)
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mask = 0x0000ff;
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else if (chan < 16)
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mask = 0x00ff00;
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else if (chan < 20)
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mask = 0x0f0000;
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else
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mask = 0xf00000;
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ret = comedi_dio_insn_config(dev, s, insn, data, mask);
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if (ret)
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return ret;
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subdev_8255_do_config(dev, s);
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return insn->n;
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}
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static int __subdev_8255_init(struct comedi_device *dev,
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struct comedi_subdevice *s,
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int (*io)(struct comedi_device *dev,
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int dir, int port, int data,
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unsigned long regbase),
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unsigned long regbase,
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bool is_mmio)
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{
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struct subdev_8255_private *spriv;
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spriv = comedi_alloc_spriv(s, sizeof(*spriv));
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if (!spriv)
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return -ENOMEM;
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if (io)
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spriv->io = io;
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else if (is_mmio)
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spriv->io = subdev_8255_mmio;
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else
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spriv->io = subdev_8255_io;
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spriv->regbase = regbase;
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s->type = COMEDI_SUBD_DIO;
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s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
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s->n_chan = 24;
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s->range_table = &range_digital;
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s->maxdata = 1;
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s->insn_bits = subdev_8255_insn;
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s->insn_config = subdev_8255_insn_config;
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subdev_8255_do_config(dev, s);
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return 0;
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}
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/**
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* subdev_8255_init - initialize DIO subdevice for driving I/O mapped 8255
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* @dev: comedi device owning subdevice
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* @s: comedi subdevice to initialize
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* @io: (optional) register I/O call-back function
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* @regbase: offset of 8255 registers from dev->iobase, or call-back context
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*
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* Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip.
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*
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* If the optional I/O call-back function is provided, its prototype is of
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* the following form:
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*
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* int my_8255_callback(struct comedi_device *dev, int dir, int port,
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* int data, unsigned long regbase);
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*
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* where 'dev', and 'regbase' match the values passed to this function,
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* 'port' is the 8255 port number 0 to 3 (including the control port), 'dir'
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* is the direction (0 for read, 1 for write) and 'data' is the value to be
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* written. It should return 0 if writing or the value read if reading.
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*
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* If the optional I/O call-back function is not provided, an internal
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* call-back function is used which uses consecutive I/O port addresses
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* starting at dev->iobase + regbase.
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*
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* Return: -ENOMEM if failed to allocate memory, zero on success.
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*/
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int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s,
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int (*io)(struct comedi_device *dev, int dir, int port,
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int data, unsigned long regbase),
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unsigned long regbase)
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{
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return __subdev_8255_init(dev, s, io, regbase, false);
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}
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EXPORT_SYMBOL_GPL(subdev_8255_init);
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/**
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* subdev_8255_mm_init - initialize DIO subdevice for driving mmio-mapped 8255
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* @dev: comedi device owning subdevice
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* @s: comedi subdevice to initialize
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* @io: (optional) register I/O call-back function
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* @regbase: offset of 8255 registers from dev->mmio, or call-back context
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*
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* Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip.
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*
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* If the optional I/O call-back function is provided, its prototype is of
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* the following form:
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*
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* int my_8255_callback(struct comedi_device *dev, int dir, int port,
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* int data, unsigned long regbase);
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*
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* where 'dev', and 'regbase' match the values passed to this function,
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* 'port' is the 8255 port number 0 to 3 (including the control port), 'dir'
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* is the direction (0 for read, 1 for write) and 'data' is the value to be
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* written. It should return 0 if writing or the value read if reading.
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*
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* If the optional I/O call-back function is not provided, an internal
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* call-back function is used which uses consecutive MMIO virtual addresses
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* starting at dev->mmio + regbase.
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*
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* Return: -ENOMEM if failed to allocate memory, zero on success.
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*/
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int subdev_8255_mm_init(struct comedi_device *dev, struct comedi_subdevice *s,
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int (*io)(struct comedi_device *dev, int dir, int port,
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int data, unsigned long regbase),
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unsigned long regbase)
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{
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return __subdev_8255_init(dev, s, io, regbase, true);
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}
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EXPORT_SYMBOL_GPL(subdev_8255_mm_init);
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/**
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* subdev_8255_regbase - get offset of 8255 registers or call-back context
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* @s: comedi subdevice
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*
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* Returns the 'regbase' parameter that was previously passed to to
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* subdev_8255_init() or subdev_8255_mm_init() to set up the subdevice.
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* Only valid if the subdevice was set up successfully.
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*/
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unsigned long subdev_8255_regbase(struct comedi_subdevice *s)
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{
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struct subdev_8255_private *spriv = s->private;
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return spriv->regbase;
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}
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EXPORT_SYMBOL_GPL(subdev_8255_regbase);
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static int __init comedi_8255_module_init(void)
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{
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return 0;
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}
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module_init(comedi_8255_module_init);
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static void __exit comedi_8255_module_exit(void)
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{
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}
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module_exit(comedi_8255_module_exit);
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MODULE_AUTHOR("Comedi http://www.comedi.org");
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MODULE_DESCRIPTION("Comedi: Generic 8255 digital I/O support");
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MODULE_LICENSE("GPL");
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