Staging: comedi: add pcmda12 driver

Driver for Winsystems PC-104 based PCM-D/A-12 8-channel AO board.

From: Calin Culianu <calin@ajvar.org>
Cc: David Schleef <ds@schleef.org>
Cc: Frank Mori Hess <fmhess@users.sourceforge.net>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/comedi/drivers/pcmda12.c

+/*
+    comedi/drivers/pcmda12.c
+    Driver for Winsystems PC-104 based PCM-D/A-12 8-channel AO board.
+
+    COMEDI - Linux Control and Measurement Device Interface
+    Copyright (C) 2006 Calin A. Culianu <calin@ajvar.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.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+/*
+Driver: pcmda12
+Description: A driver for the Winsystems PCM-D/A-12
+Devices: [Winsystems] PCM-D/A-12 (pcmda12)
+Author: Calin Culianu <calin@ajvar.org>
+Updated: Fri, 13 Jan 2006 12:01:01 -0500
+Status: works
+
+A driver for the relatively straightforward-to-program PCM-D/A-12.
+This board doesn't support commands, and the only way to set its
+analog output range is to jumper the board.  As such,
+comedi_data_write() ignores the range value specified.
+
+The board uses 16 consecutive I/O addresses starting at the I/O port
+base address.  Each address corresponds to the LSB then MSB of a
+particular channel from 0-7.
+
+Note that the board is not ISA-PNP capable and thus
+needs the I/O port comedi_config parameter.
+
+Note that passing a nonzero value as the second config option will
+enable "simultaneous xfer" mode for this board, in which AO writes
+will not take effect until a subsequent read of any AO channel.  This
+is so that one can speed up programming by preloading all AO registers
+with values before simultaneously setting them to take effect with one
+read command.
+
+Configuration Options:
+  [0] - I/O port base address
+  [1] - Do Simultaneous Xfer (see description)
+*/
+
+#include "../comedidev.h"
+
+#include <linux/pci.h>		/* for PCI devices */
+
+#define MIN(a,b) ( ((a) < (b)) ? (a) : (b) )
+#define SDEV_NO ((int)(s - dev->subdevices))
+#define CHANS 8
+#define IOSIZE 16
+#define LSB(x) ((unsigned char)((x) & 0xff))
+#define MSB(x) ((unsigned char)((((unsigned short)(x))>>8) & 0xff))
+#define LSB_PORT(chan) (dev->iobase + (chan)*2)
+#define MSB_PORT(chan) (LSB_PORT(chan)+1)
+#define BITS 12
+
+/*
+ * Bords
+ */
+typedef struct pcmda12_board_struct {
+	const char *name;
+} pcmda12_board;
+
+/* note these have no effect and are merely here for reference..
+   these are configured by jumpering the board! */
+static const comedi_lrange pcmda12_ranges = {
+	3,
+	{
+			UNI_RANGE(5), UNI_RANGE(10), BIP_RANGE(5)
+		}
+};
+
+static const pcmda12_board pcmda12_boards[] = {
+	{
+	      name:	"pcmda12",
+		},
+};
+
+/*
+ * Useful for shorthand access to the particular board structure
+ */
+#define thisboard ((const pcmda12_board *)dev->board_ptr)
+
+typedef struct {
+	lsampl_t ao_readback[CHANS];
+	int simultaneous_xfer_mode;
+} pcmda12_private;
+
+#define devpriv ((pcmda12_private *)(dev->private))
+
+/*
+ * The comedi_driver structure tells the Comedi core module
+ * which functions to call to configure/deconfigure (attach/detach)
+ * the board, and also about the kernel module that contains
+ * the device code.
+ */
+static int pcmda12_attach(comedi_device * dev, comedi_devconfig * it);
+static int pcmda12_detach(comedi_device * dev);
+
+static void zero_chans(comedi_device * dev);
+
+static comedi_driver driver = {
+      driver_name:"pcmda12",
+      module:THIS_MODULE,
+      attach:pcmda12_attach,
+      detach:pcmda12_detach,
+/* It is not necessary to implement the following members if you are
+ * writing a driver for a ISA PnP or PCI card */
+	/* Most drivers will support multiple types of boards by
+	 * having an array of board structures.  These were defined
+	 * in pcmda12_boards[] above.  Note that the element 'name'
+	 * was first in the structure -- Comedi uses this fact to
+	 * extract the name of the board without knowing any details
+	 * about the structure except for its length.
+	 * When a device is attached (by comedi_config), the name
+	 * of the device is given to Comedi, and Comedi tries to
+	 * match it by going through the list of board names.  If
+	 * there is a match, the address of the pointer is put
+	 * into dev->board_ptr and driver->attach() is called.
+	 *
+	 * Note that these are not necessary if you can determine
+	 * the type of board in software.  ISA PnP, PCI, and PCMCIA
+	 * devices are such boards.
+	 */
+      board_name:&pcmda12_boards[0].name,
+      offset:sizeof(pcmda12_board),
+      num_names:sizeof(pcmda12_boards) / sizeof(pcmda12_board),
+};
+
+static int ao_winsn(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data);
+static int ao_rinsn(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data);
+
+/*
+ * Attach is called by the Comedi core to configure the driver
+ * for a particular board.  If you specified a board_name array
+ * in the driver structure, dev->board_ptr contains that
+ * address.
+ */
+static int pcmda12_attach(comedi_device * dev, comedi_devconfig * it)
+{
+	comedi_subdevice *s;
+	unsigned long iobase;
+
+	iobase = it->options[0];
+	printk("comedi%d: %s: io: %lx %s ", dev->minor, driver.driver_name,
+		iobase, it->options[1] ? "simultaneous xfer mode enabled" : "");
+
+	if (!request_region(iobase, IOSIZE, driver.driver_name)) {
+		printk("I/O port conflict\n");
+		return -EIO;
+	}
+	dev->iobase = iobase;
+
+/*
+ * Initialize dev->board_name.  Note that we can use the "thisboard"
+ * macro now, since we just initialized it in the last line.
+ */
+	dev->board_name = thisboard->name;
+
+/*
+ * Allocate the private structure area.  alloc_private() is a
+ * convenient macro defined in comedidev.h.
+ */
+	if (alloc_private(dev, sizeof(pcmda12_private)) < 0) {
+		printk("cannot allocate private data structure\n");
+		return -ENOMEM;
+	}
+
+	devpriv->simultaneous_xfer_mode = it->options[1];
+
+	/*
+	 * Allocate the subdevice structures.  alloc_subdevice() is a
+	 * convenient macro defined in comedidev.h.
+	 *
+	 * Allocate 2 subdevs (32 + 16 DIO lines) or 3 32 DIO subdevs for the
+	 * 96-channel version of the board.
+	 */
+	if (alloc_subdevices(dev, 1) < 0) {
+		printk("cannot allocate subdevice data structures\n");
+		return -ENOMEM;
+	}
+
+	s = dev->subdevices;
+	s->private = NULL;
+	s->maxdata = (0x1 << BITS) - 1;
+	s->range_table = &pcmda12_ranges;
+	s->type = COMEDI_SUBD_AO;
+	s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
+	s->n_chan = CHANS;
+	s->insn_write = &ao_winsn;
+	s->insn_read = &ao_rinsn;
+
+	zero_chans(dev);	/* clear out all the registers, basically */
+
+	printk("attached\n");
+
+	return 1;
+}
+
+/*
+ * _detach is called to deconfigure a device.  It should deallocate
+ * resources.
+ * This function is also called when _attach() fails, so it should be
+ * careful not to release resources that were not necessarily
+ * allocated by _attach().  dev->private and dev->subdevices are
+ * deallocated automatically by the core.
+ */
+static int pcmda12_detach(comedi_device * dev)
+{
+	printk("comedi%d: %s: remove\n", dev->minor, driver.driver_name);
+	if (dev->iobase)
+		release_region(dev->iobase, IOSIZE);
+	return 0;
+}
+
+static void zero_chans(comedi_device * dev)
+{				/* sets up an
+				   ASIC chip to defaults */
+	int i;
+	for (i = 0; i < CHANS; ++i) {
+/*      /\* do this as one instruction?? *\/ */
+/*      outw(0, LSB_PORT(chan)); */
+		outb(0, LSB_PORT(i));
+		outb(0, MSB_PORT(i));
+	}
+	inb(LSB_PORT(0));	/* update chans. */
+}
+
+static int ao_winsn(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data)
+{
+	int i;
+	int chan = CR_CHAN(insn->chanspec);
+
+	/* Writing a list of values to an AO channel is probably not
+	 * very useful, but that's how the interface is defined. */
+	for (i = 0; i < insn->n; ++i) {
+
+/*      /\* do this as one instruction?? *\/ */
+/*      outw(data[i], LSB_PORT(chan)); */
+
+		/* Need to do this as two instructions due to 8-bit bus?? */
+		/*  first, load the low byte */
+		outb(LSB(data[i]), LSB_PORT(chan));
+		/*  next, write the high byte */
+		outb(MSB(data[i]), MSB_PORT(chan));
+
+		/* save shadow register */
+		devpriv->ao_readback[chan] = data[i];
+
+		if (!devpriv->simultaneous_xfer_mode)
+			inb(LSB_PORT(chan));
+	}
+
+	/* return the number of samples written */
+	return i;
+}
+
+/* AO subdevices should have a read insn as well as a write insn.
+
+   Usually this means copying a value stored in devpriv->ao_readback.
+   However, since this driver supports simultaneous xfer then sometimes
+   this function actually accomplishes work.
+
+   Simultaneaous xfer mode is accomplished by loading ALL the values
+   you want for AO in all the channels, then READing off one of the AO
+   registers to initiate the instantaneous simultaneous update of all
+   DAC outputs, which makes all AO channels update simultaneously.
+   This is useful for some control applications, I would imagine.
+*/
+static int ao_rinsn(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data)
+{
+	int i;
+	int chan = CR_CHAN(insn->chanspec);
+
+	for (i = 0; i < insn->n; i++) {
+		if (devpriv->simultaneous_xfer_mode)
+			inb(LSB_PORT(chan));
+		/* read back shadow register */
+		data[i] = devpriv->ao_readback[chan];
+	}
+
+	return i;
+}
+
+/*
+ * A convenient macro that defines init_module() and cleanup_module(),
+ * as necessary.
+ */
+COMEDI_INITCLEANUP(driver);