/*
    comedi/drivers/8255.c
    Driver for 8255

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 1998 David A. Schleef <ds@schleef.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
*/
/*
Driver: 8255
Description: generic 8255 support
Devices: [standard] 8255 (8255)
Author: ds
Status: works
Updated: Fri,  7 Jun 2002 12:56:45 -0700

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.

You should enable compilation this driver if you plan to use a board
that has an 8255 chip.  For multifunction boards, the main driver will
configure the 8255 subdevice automatically.

This driver also works independently with ISA and PCI cards that
directly map the 8255 registers to I/O ports, including cards with
multiple 8255 chips.  To configure the driver for such a card, the
option list should be a list of the I/O port bases for each of the
8255 chips.  For example,

  comedi_config /dev/comedi0 8255 0x200,0x204,0x208,0x20c

Note that most PCI 8255 boards do NOT work with this driver, and
need a separate driver as a wrapper.  For those that do work, the
I/O port base address can be found in the output of 'lspci -v'.

*/

/*
   This file contains an exported subdevice for driving an 8255.

   To use this subdevice as part of another driver, you need to
   set up the subdevice in the attach function of the driver by
   calling:

     subdev_8255_init(device, subdevice, io_function, iobase)

   device and subdevice are pointers to the device and subdevice
   structures.  io_function will be called to provide the
   low-level input/output to the device, i.e., actual register
   access.  io_function will be called with the value of iobase
   as the last parameter.  If the 8255 device is mapped as 4
   consecutive I/O ports, you can use NULL for io_function
   and the I/O port base for iobase, and an internal function will
   handle the register access.

   In addition, if the main driver handles interrupts, you can
   enable commands on the subdevice by calling subdev_8255_init_irq()
   instead.  Then, when you get an interrupt that is likely to be
   from the 8255, you should call subdev_8255_interrupt(), which
   will copy the latched value to a Comedi buffer.
 */

#include <linux/module.h>
#include "../comedidev.h"

#include "comedi_fc.h"
#include "8255.h"

struct subdev_8255_private {
	unsigned long regbase;
	int (*io)(struct comedi_device *, int, int, int, unsigned long);
};

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 *,
					int, int, int, unsigned long),
			      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;
}

int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s,
		     int (*io)(struct comedi_device *,
			       int, int, int, unsigned long),
		     unsigned long regbase)
{
	return __subdev_8255_init(dev, s, io, regbase, false);
}
EXPORT_SYMBOL_GPL(subdev_8255_init);

int subdev_8255_mm_init(struct comedi_device *dev, struct comedi_subdevice *s,
			int (*io)(struct comedi_device *,
				  int, int, int, unsigned long),
			unsigned long regbase)
{
	return __subdev_8255_init(dev, s, io, regbase, true);
}
EXPORT_SYMBOL_GPL(subdev_8255_mm_init);
/*

   Start of the 8255 standalone device

 */

static int dev_8255_attach(struct comedi_device *dev,
			   struct comedi_devconfig *it)
{
	struct comedi_subdevice *s;
	unsigned long iobase;
	int ret;
	int i;

	for (i = 0; i < COMEDI_NDEVCONFOPTS; i++) {
		iobase = it->options[i];
		if (!iobase)
			break;
	}
	if (i == 0) {
		dev_warn(dev->class_dev, "no devices specified\n");
		return -EINVAL;
	}

	ret = comedi_alloc_subdevices(dev, i);
	if (ret)
		return ret;

	for (i = 0; i < dev->n_subdevices; i++) {
		s = &dev->subdevices[i];
		iobase = it->options[i];

		/*
		 * __comedi_request_region() does not set dev->iobase.
		 *
		 * For 8255 devices that are manually attached using
		 * comedi_config, the 'iobase' is the actual I/O port
		 * base address of the chip.
		 */
		ret = __comedi_request_region(dev, iobase, I8255_SIZE);
		if (ret) {
			s->type = COMEDI_SUBD_UNUSED;
		} else {
			ret = subdev_8255_init(dev, s, NULL, iobase);
			if (ret)
				return ret;
		}
	}

	return 0;
}

static void dev_8255_detach(struct comedi_device *dev)
{
	struct comedi_subdevice *s;
	struct subdev_8255_private *spriv;
	int i;

	for (i = 0; i < dev->n_subdevices; i++) {
		s = &dev->subdevices[i];
		if (s->type != COMEDI_SUBD_UNUSED) {
			spriv = s->private;
			release_region(spriv->regbase, I8255_SIZE);
		}
	}
}

static struct comedi_driver dev_8255_driver = {
	.driver_name	= "8255",
	.module		= THIS_MODULE,
	.attach		= dev_8255_attach,
	.detach		= dev_8255_detach,
};
module_comedi_driver(dev_8255_driver);

MODULE_AUTHOR("Comedi http://www.comedi.org");
MODULE_DESCRIPTION("Comedi low-level driver");
MODULE_LICENSE("GPL");