--- /dev/null
+/*
+ * 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>
+ *
+ * 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.
+ */
+
+/*
+ * 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 "../comedidev.h"
+
+#include "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 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 http://www.comedi.org");
+MODULE_DESCRIPTION("Comedi: Generic 8255 digital I/O support");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff