new driver from abbotti@mev.co.uk (Ian Abbott):
authorFrank Mori Hess <fmhess@speakeasy.net>
Tue, 8 Mar 2005 02:35:34 +0000 (02:35 +0000)
committerFrank Mori Hess <fmhess@speakeasy.net>
Tue, 8 Mar 2005 02:35:34 +0000 (02:35 +0000)
Here's a new driver for the Amplicon PCI224 and PCI234 analog output cards,
supporting streaming AO.  It seems to be working well except that the first scan
can misfire at the start of acquisition, and I can't find a way to work around
this hardware problem.  It shouldn't matter too much for waveform output.  I've
mentioned it in the caveats section of the driver documentation.

comedi/drivers/Makefile.am
comedi/drivers/amplc_pci224.c [new file with mode: 0644]

index 4ba14715c2604a39f4e6a843f12d76de078c7642..d6095a2e980c8006fe127591c36013c842498d90 100644 (file)
@@ -89,6 +89,7 @@ module_PROGRAMS = \
  adl_pci9118.ko \
  adv_pci1710.ko \
  adv_pci_dio.ko \
+ amplc_pci224.ko \
  amplc_pci230.ko \
  amplc_pc236.ko \
  amplc_pc263.ko \
@@ -159,6 +160,7 @@ adl_pci9118_ko_SOURCES = adl_pci9118.c
 adv_pci1710_ko_SOURCES = adv_pci1710.c
 amcc_s5933_ko_SOURCES = amcc_s5933.c
 adv_pci_dio_ko_SOURCES = adv_pci_dio.c
+amplc_pci224_ko_SOURCES = amplc_pci224.c
 amplc_pci230_ko_SOURCES = amplc_pci230.c
 amplc_pc236_ko_SOURCES = amplc_pc236.c
 amplc_pc263_ko_SOURCES = amplc_pc263.c
diff --git a/comedi/drivers/amplc_pci224.c b/comedi/drivers/amplc_pci224.c
new file mode 100644 (file)
index 0000000..3557294
--- /dev/null
@@ -0,0 +1,1585 @@
+/*
+    comedi/drivers/amplc_pci224.c
+    Driver for Amplicon PCI224 and PCI234 AO boards.
+
+    Copyright (C) 2005 MEV Ltd. <http://www.mev.co.uk/>
+
+    COMEDI - Linux Control and Measurement Device Interface
+    Copyright (C) 1998,2000 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.
+
+    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: amplc_pci224.o
+Description: Amplicon PCI224, PCI234
+Author: Ian Abbott <abbotti@mev.co.uk>
+Devices: [Amplicon] PCI224 (pci224), PCI234 (pci234)
+Updated: Thu, 24 Feb 2005 12:29:26 +0000
+Status: works, but see caveats
+
+Supports:
+
+  - ao_insn read/write
+  - ao_do_cmd mode with the following sources:
+
+    - start_src         TRIG_INT        TRIG_EXT
+    - scan_begin_src    TRIG_TIMER      TRIG_EXT
+    - convert_src       TRIG_NOW
+    - scan_end_src      TRIG_COUNT
+    - stop_src          TRIG_COUNT      TRIG_EXT        TRIG_NONE
+
+    The channel list must contain at least one channel with no repeated
+    channels.  The scan end count must equal the number of channels in
+    the channel list.
+
+    There is only one external trigger source so only one of start_src,
+    scan_begin_src or stop_src may use TRIG_EXT.
+
+Configuration options - PCI224:
+  [0] - PCI bus of device (optional).
+  [1] - PCI slot of device (optional).
+          If bus/slot is not specified, the first available PCI device
+          will be used.
+  [2] - Select available ranges according to jumper LK1.  All channels
+        are set to the same range:
+        0=Jumper position 1-2 (factory default), 4 software-selectable
+          internal voltage references, giving 4 bipolar and 4 unipolar
+          ranges:
+            [-10V,+10V], [-5V,+5V], [-2.5V,+2.5V], [-1.25V,+1.25V],
+            [0,+10V], [0,+5V], [0,+2.5V], [0,1.25V].
+        1=Jumper position 2-3, 1 external voltage reference, giving
+          1 bipolar and 1 unipolar range:
+            [-Vext,+Vext], [0,+Vext].
+
+Configuration options - PCI234:
+  [0] - PCI bus of device (optional).
+  [1] - PCI slot of device (optional).
+          If bus/slot is not specified, the first available PCI device
+          will be used.
+  [2] - Select internal or external voltage reference according to
+        jumper LK1.  This affects all channels:
+        0=Jumper position 1-2 (factory default), Vref=5V internal.
+        1=Jumper position 2-3, Vref=Vext external.
+  [3] - Select channel 0 range according to jumper LK2:
+        0=Jumper position 2-3 (factory default), range [-2*Vref,+2*Vref]
+          (10V bipolar when options[2]=0).
+        1=Jumper position 1-2, range [-Vref,+Vref]
+          (5V bipolar when options[2]=0).
+  [4] - Select channel 1 range according to jumper LK3: cf. options[3].
+  [5] - Select channel 2 range according to jumper LK4: cf. options[3].
+  [6] - Select channel 3 range according to jumper LK5: cf. options[3].
+
+Passing a zero for an option is the same as leaving it unspecified.
+
+Caveats:
+
+  1) All channels on the PCI224 share the same range.  Any change to the
+     range as a result of insn_write or a streaming command will affect
+     the output voltages of all channels, including those not specified
+     by the instruction or command.
+
+  2) For the analog output command,  the first scan may be triggered
+     falsely at the start of acquisition.  This occurs when the DAC scan
+     trigger source is switched from 'none' to 'timer' (scan_begin_src =
+     TRIG_TIMER) or 'external' (scan_begin_src == TRIG_EXT) at the start
+     of acquisition and the trigger source is at logic level 1 at the
+     time of the switch.  This is very likely for TRIG_TIMER.  For
+     TRIG_EXT, it depends on the state of the external line and whether
+     the CR_INVERT flag has been set.  The remaining scans are triggered
+     correctly.
+*/
+
+#include <linux/comedidev.h>
+
+#include <linux/pci.h>
+
+#include "comedi_fc.h"
+#include "8253.h"
+
+#define DRIVER_NAME    "amplc_pci224"
+
+/*
+ * PCI IDs.
+ */
+/* #define PCI_VENDOR_ID_AMPLICON 0x14dc */
+#define PCI_DEVICE_ID_AMPLICON_PCI224 0x0007
+#define PCI_DEVICE_ID_AMPLICON_PCI234 0x0008
+
+/*
+ * PCI224/234 i/o space 1 (PCIBAR2) registers.
+ */
+#define PCI224_IO1_SIZE        0x20    /* Size of i/o space 1 (8-bit registers) */
+#define PCI224_Z2_CT0  0x14    /* 82C54 counter/timer 0 */
+#define PCI224_Z2_CT1  0x15    /* 82C54 counter/timer 1 */
+#define PCI224_Z2_CT2  0x16    /* 82C54 counter/timer 2 */
+#define PCI224_Z2_CTC  0x17    /* 82C54 counter/timer control word */
+#define PCI224_ZCLK_SCE        0x1A    /* Group Z Clock Configuration Register */
+#define PCI224_ZGAT_SCE        0x1D    /* Group Z Gate Configuration Register */
+#define PCI224_INT_SCE 0x1E    /* ISR Interrupt source mask register/Interrupt status */
+
+/*
+ * PCI224/234 i/o space 2 (PCIBAR3) 16-bit registers.
+ */
+#define PCI224_IO2_SIZE        0x10    /* Size of i/o space 2 (16-bit registers). */
+#define PCI224_DACDATA 0x00    /* (w-o) DAC FIFO data. */
+#define PCI224_SOFTTRIG        0x00    /* (r-o) DAC software scan trigger. */
+#define PCI224_DACCON  0x02    /* (r/w) DAC status/configuration. */
+#define PCI224_FIFOSIZ 0x04    /* (w-o) FIFO size for wraparound mode. */
+#define PCI224_DACCEN  0x06    /* (w-o) DAC channel enable register. */
+
+/*
+ * DACCON values.
+ */
+/* (r/w) Scan trigger. */
+#define PCI224_DACCON_TRIG_MASK                (7 << 0)
+#define PCI224_DACCON_TRIG_NONE                (0 << 0)        /* none */
+#define PCI224_DACCON_TRIG_SW          (1 << 0)        /* software trig */
+#define PCI224_DACCON_TRIG_EXTP                (2 << 0)        /* ext +ve edge */
+#define PCI224_DACCON_TRIG_EXTN                (3 << 0)        /* ext -ve edge */
+#define PCI224_DACCON_TRIG_Z2CT0       (4 << 0)        /* Z2 CT0 out */
+#define PCI224_DACCON_TRIG_Z2CT1       (5 << 0)        /* Z2 CT1 out */
+#define PCI224_DACCON_TRIG_Z2CT2       (6 << 0)        /* Z2 CT2 out */
+/* (r/w) Polarity (PCI224 only, PCI234 always bipolar!). */
+#define PCI224_DACCON_POLAR_MASK       (1 << 3)
+#define PCI224_DACCON_POLAR_UNI                (0 << 3)        /* range [0,Vref] */
+#define PCI224_DACCON_POLAR_BI         (1 << 3)        /* range [-Vref,+Vref]*/
+/* (r/w) Internal Vref (PCI224 only, when LK1 in position 1-2). */
+#define PCI224_DACCON_VREF_MASK                (3 << 4)
+#define PCI224_DACCON_VREF_1_25                (0 << 4)        /* Vref = 1.25V */
+#define PCI224_DACCON_VREF_2_5         (1 << 4)        /* Vref = 2.5V */
+#define PCI224_DACCON_VREF_5           (2 << 4)        /* Vref = 5V */
+#define PCI224_DACCON_VREF_10          (3 << 4)        /* Vref = 10V */
+/* (r/w) Wraparound mode enable (to play back stored waveform). */
+#define PCI224_DACCON_FIFOWRAP         (1 << 7)
+/* (r/w) FIFO enable.  It MUST be set! */
+#define PCI224_DACCON_FIFOENAB         (1 << 8)
+/* (r/w) FIFO interrupt trigger level (most values are not very useful). */
+#define PCI224_DACCON_FIFOINTR_MASK    (7 << 9)
+#define PCI224_DACCON_FIFOINTR_EMPTY   (0 << 9)        /* when empty */
+#define PCI224_DACCON_FIFOINTR_NEMPTY  (1 << 9)        /* when not empty */
+#define PCI224_DACCON_FIFOINTR_NHALF   (2 << 9)        /* when not half full */
+#define PCI224_DACCON_FIFOINTR_HALF    (3 << 9)        /* when half full */
+#define PCI224_DACCON_FIFOINTR_NFULL   (4 << 9)        /* when not full */
+#define PCI224_DACCON_FIFOINTR_FULL    (5 << 9)        /* when full */
+/* (r-o) FIFO fill level. */
+#define PCI224_DACCON_FIFOFL_MASK      (7 << 12)
+#define PCI224_DACCON_FIFOFL_EMPTY     (1 << 12)       /* 0 */
+#define PCI224_DACCON_FIFOFL_ONETOHALF (0 << 12)       /* [1,2048] */
+#define PCI224_DACCON_FIFOFL_HALFTOFULL        (4 << 12)       /* [2049,4095] */
+#define PCI224_DACCON_FIFOFL_FULL      (6 << 12)       /* 4096 */
+/* (r-o) DAC busy flag. */
+#define PCI224_DACCON_BUSY             (1 << 15)
+/* (w-o) FIFO reset. */
+#define PCI224_DACCON_FIFORESET                (1 << 12)
+/* (w-o) Global reset (not sure what it does). */
+#define PCI224_DACCON_GLOBALRESET      (1 << 13)
+
+/*
+ * DAC FIFO size.
+ */
+#define PCI224_FIFO_SIZE       4096
+
+/*
+ * DAC FIFO guaranteed minimum room available, depending on reported fill level.
+ * The maximum room available depends on the reported fill level and how much
+ * has been written!
+ */
+#define PCI224_FIFO_ROOM_EMPTY         PCI224_FIFO_SIZE
+#define PCI224_FIFO_ROOM_ONETOHALF     (PCI224_FIFO_SIZE / 2)
+#define PCI224_FIFO_ROOM_HALFTOFULL    1
+#define PCI224_FIFO_ROOM_FULL          0
+
+/*
+ * Counter/timer clock input configuration sources.
+ */
+#define CLK_CLK                0       /* reserved (channel-specific clock) */
+#define CLK_10MHZ      1       /* internal 10 MHz clock */
+#define CLK_1MHZ       2       /* internal 1 MHz clock */
+#define CLK_100KHZ     3       /* internal 100 kHz clock */
+#define CLK_10KHZ      4       /* internal 10 kHz clock */
+#define CLK_1KHZ       5       /* internal 1 kHz clock */
+#define CLK_OUTNM1     6       /* output of channel-1 modulo total */
+#define CLK_EXT                7       /* external clock */
+/* Macro to construct clock input configuration register value. */
+#define CLK_CONFIG(chan, src)  ((((chan) & 3) << 3) | ((src) & 7))
+/* Timebases in ns. */
+#define TIMEBASE_10MHZ         100
+#define TIMEBASE_1MHZ          1000
+#define TIMEBASE_100KHZ                10000
+#define TIMEBASE_10KHZ         100000
+#define TIMEBASE_1KHZ          1000000
+
+/*
+ * Counter/timer gate input configuration sources.
+ */
+#define GAT_VCC                0       /* VCC (i.e. enabled) */
+#define GAT_GND                1       /* GND (i.e. disabled) */
+#define GAT_EXT                2       /* reserved (external gate input) */
+#define GAT_NOUTNM2    3       /* inverted output of channel-2 modulo total */
+/* Macro to construct gate input configuration register value. */
+#define GAT_CONFIG(chan, src)  ((((chan) & 3) << 3) | ((src) & 7))
+
+/*
+ * Summary of CLK_OUTNM1 and GAT_NOUTNM2 connections for PCI224 and PCI234:
+ *
+ *              Channel's       Channel's
+ *              clock input     gate input
+ * Channel      CLK_OUTNM1      GAT_NOUTNM2
+ * -------      ----------      -----------
+ * Z2-CT0       Z2-CT2-OUT      /Z2-CT1-OUT
+ * Z2-CT1       Z2-CT0-OUT      /Z2-CT2-OUT
+ * Z2-CT2       Z2-CT1-OUT      /Z2-CT0-OUT
+ */
+
+/*
+ * Interrupt enable/status bits
+ */
+#define PCI224_INTR_EXT                0x01    /* rising edge on external input */
+#define PCI224_INTR_DAC                0x04    /* DAC (FIFO) interrupt */
+#define PCI224_INTR_Z2CT1      0x20    /* rising edge on Z2-CT1 output */
+
+#define PCI224_INTR_EDGE_BITS  (PCI224_INTR_EXT | PCI224_INTR_Z2CT1)
+#define PCI224_INTR_LEVEL_BITS PCI224_INTR_DACFIFO
+
+/*
+ * Handy macros.
+ */
+
+/* Combine old and new bits. */
+#define COMBINE(old, new, mask)        (((old) & ~(mask)) | ((new) & (mask)))
+
+/* A generic null function pointer value.  */
+#define NULLFUNC       0
+
+/* Current CPU.  XXX should this be hard_smp_processor_id()? */
+#define THISCPU                smp_processor_id()
+
+/*
+ * Range tables.
+ */
+
+/* The software selectable internal ranges for PCI224 (option[2] == 0). */
+static comedi_lrange range_pci224_internal = {
+       8,
+       {
+               BIP_RANGE(10),
+               BIP_RANGE(5),
+               BIP_RANGE(2.5),
+               BIP_RANGE(1.25),
+               UNI_RANGE(10),
+               UNI_RANGE(5),
+               UNI_RANGE(2.5),
+               UNI_RANGE(1.25),
+       }
+};
+
+static unsigned short hwrange_pci224_internal[8] = {
+       PCI224_DACCON_POLAR_BI | PCI224_DACCON_VREF_10,
+       PCI224_DACCON_POLAR_BI | PCI224_DACCON_VREF_5,
+       PCI224_DACCON_POLAR_BI | PCI224_DACCON_VREF_2_5,
+       PCI224_DACCON_POLAR_BI | PCI224_DACCON_VREF_1_25,
+       PCI224_DACCON_POLAR_UNI | PCI224_DACCON_VREF_10,
+       PCI224_DACCON_POLAR_UNI | PCI224_DACCON_VREF_5,
+       PCI224_DACCON_POLAR_UNI | PCI224_DACCON_VREF_2_5,
+       PCI224_DACCON_POLAR_UNI | PCI224_DACCON_VREF_1_25,
+};
+
+/* The software selectable external ranges for PCI224 (option[2] == 1). */
+static comedi_lrange range_pci224_external = {
+       2,
+       {
+               RANGE_ext(-1, 1),       /* bipolar [-Vref,+Vref] */
+               RANGE_ext(0, 1),        /* unipolar [0,+Vref] */
+       }
+};
+
+static unsigned short hwrange_pci224_external[2] = {
+       PCI224_DACCON_POLAR_BI,
+       PCI224_DACCON_POLAR_UNI,
+};
+
+/* The hardware selectable Vref*2 external range for PCI234
+ * (option[2] == 1, option[3+n] == 0). */
+static comedi_lrange range_pci234_ext2 = {
+       1,
+       {
+               RANGE_ext(-2, 2),
+       }
+};
+
+/* The hardware selectable Vref external range for PCI234
+ * (option[2] == 1, option[3+n] == 1). */
+static comedi_lrange range_pci234_ext = {
+       1,
+       {
+               RANGE_ext(-1, 1),
+       }
+};
+
+/* This serves for all the PCI234 ranges. */
+static unsigned short hwrange_pci234[1] = {
+       PCI224_DACCON_POLAR_BI,         /* bipolar - hardware ignores it! */
+};
+
+
+/*
+ * Board descriptions.
+ */
+
+enum pci224_model      { pci224_model, pci234_model };
+
+typedef struct pci224_board_struct {
+       char *name;
+       enum pci224_model model;
+       unsigned int ao_chans;
+       unsigned int ao_bits;
+} pci224_board;
+
+static pci224_board pci224_boards[] = {
+       {
+       name:           "pci224",
+       model:          pci224_model,
+       ao_chans:       16,
+       ao_bits:        12,
+       },
+       {
+       name:           "pci234",
+       model:          pci234_model,
+       ao_chans:       4,
+       ao_bits:        16,
+       },
+};
+
+/*
+ * PCI driver table.
+ */
+
+static struct pci_device_id pci224_pci_table[] __devinitdata = {
+       { PCI_VENDOR_ID_AMPLICON, PCI_DEVICE_ID_AMPLICON_PCI224,
+         PCI_ANY_ID, PCI_ANY_ID, 0, 0, pci224_model },
+       { PCI_VENDOR_ID_AMPLICON, PCI_DEVICE_ID_AMPLICON_PCI234,
+         PCI_ANY_ID, PCI_ANY_ID, 0, 0, pci234_model },
+       { 0 }
+};
+MODULE_DEVICE_TABLE(pci, pci224_pci_table);
+
+/*
+ * Useful for shorthand access to the particular board structure
+ */
+#define thisboard ((pci224_board *)dev->board_ptr)
+
+/* this structure is for data unique to this hardware driver.  If
+   several hardware drivers keep similar information in this structure,
+   feel free to suggest moving the variable to the comedi_device struct.  */
+typedef struct {
+       struct pci_dev *pci_dev;        /* PCI device */
+       unsigned short *hwrange;
+       unsigned long iobase1;
+       spinlock_t ao_spinlock;
+       lsampl_t *ao_readback;
+       sampl_t *ao_scan_vals;
+       unsigned char *ao_scan_order;
+       int intr_cpuid;
+       short intr_running;
+       short ao_cmd_running;
+       unsigned short daccon;
+       unsigned int cached_div1;
+       unsigned int cached_div2;
+       unsigned int ao_stop_count;
+       short ao_stop_continuous;
+       unsigned short ao_enab; /* max 16 channels so 'short' will do */
+       unsigned char intsce;
+} pci224_private;
+
+#define devpriv ((pci224_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 pci224_attach(comedi_device *dev,comedi_devconfig *it);
+static int pci224_detach(comedi_device *dev);
+static comedi_driver driver_amplc_pci224 = {
+       driver_name:    DRIVER_NAME,
+       module:         THIS_MODULE,
+       attach:         pci224_attach,
+       detach:         pci224_detach,
+       board_name:     pci224_boards,
+       offset:         sizeof(pci224_board),
+       num_names:      sizeof(pci224_boards) / sizeof(pci224_board),
+};
+COMEDI_INITCLEANUP(driver_amplc_pci224);
+
+/*
+ * Called from the 'insn_write' function to perform a single write.
+ */
+static void
+pci224_ao_set_data(comedi_device *dev, int chan, int range, lsampl_t data)
+{
+       unsigned short mangled;
+
+       /* Store unmangled data for readback. */
+       devpriv->ao_readback[chan] = data;
+       /* Enable the channel. */
+       outw(1 << chan, dev->iobase + PCI224_DACCEN);
+       /* Set range and reset FIFO. */
+       devpriv->daccon = COMBINE(devpriv->daccon, devpriv->hwrange[range],
+                       (PCI224_DACCON_POLAR_MASK | PCI224_DACCON_VREF_MASK));
+       outw(devpriv->daccon | PCI224_DACCON_FIFORESET,
+                       dev->iobase + PCI224_DACCON);
+       /*
+        * Mangle the data.  The hardware expects:
+        * - bipolar: 16-bit 2's complement
+        * - unipolar: 16-bit unsigned
+        */
+       mangled = (unsigned short)data << (16 - thisboard->ao_bits);
+       if ((devpriv->daccon & PCI224_DACCON_POLAR_MASK) ==
+                       PCI224_DACCON_POLAR_BI) {
+               mangled ^= 0x8000;
+       }
+       /* Write mangled data to the FIFO. */
+       outw(mangled, dev->iobase + PCI224_DACDATA);
+       /* Trigger the conversion. */
+       inw(dev->iobase + PCI224_SOFTTRIG);
+}
+
+/*
+ * 'insn_write' function for AO subdevice.
+ */
+static int
+pci224_ao_insn_write(comedi_device *dev, comedi_subdevice *s,
+               comedi_insn *insn, lsampl_t *data)
+{
+       int retval;
+       int i;
+       int chan, range;
+
+       /* Unpack channel and range. */
+       chan = CR_CHAN(insn->chanspec);
+       range = CR_RANGE(insn->chanspec);
+
+       if (devpriv->ao_cmd_running) {
+               retval = -EBUSY;
+       } else {
+               /* 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++) {
+                       pci224_ao_set_data(dev, chan, range, data[i]);
+               }
+               retval = i;
+       }
+       return retval;
+}
+
+/*
+ * 'insn_read' function for AO subdevice.
+ *
+ * N.B. The value read will not be valid if the DAC channel has
+ * never been written successfully since the device was attached
+ * or since the channel has been used by an AO streaming write
+ * command.
+ */
+static int
+pci224_ao_insn_read(comedi_device *dev, comedi_subdevice *s,
+               comedi_insn *insn, lsampl_t *data)
+{
+       int i;
+       int chan;
+
+       chan = CR_CHAN(insn->chanspec);
+
+       for (i = 0; i < insn->n; i++) {
+               data[i] = devpriv->ao_readback[chan];
+       }
+
+       return i;
+}
+
+/*
+ * Just a wrapper for the inline function 'i8253_cascade_ns_to_timer'.
+ */
+static void
+pci224_cascade_ns_to_timer(int osc_base, unsigned int *d1, unsigned int *d2,
+               unsigned int *nanosec, int round_mode)
+{
+       i8253_cascade_ns_to_timer(osc_base, d1, d2, nanosec, round_mode);
+}
+
+/*
+ * Kills a command running on the AO subdevice.
+ */
+static void
+pci224_ao_stop(comedi_device *dev, comedi_subdevice *s)
+{
+       unsigned long flags;
+
+       comedi_spin_lock_irqsave(&devpriv->ao_spinlock, flags);
+       /* Turn off the internal trigger. */
+       s->async->inttrig = NULLFUNC;
+       /* Kill the interrupts. */
+       devpriv->intsce = 0;
+       outb(0, devpriv->iobase1 + PCI224_INT_SCE);
+       /*
+        * Interrupt routine may or may not be running.  We may or may not
+        * have been called from the interrupt routine (directly or
+        * indirectly via a comedi_events() callback routine).  It's highly
+        * unlikely that we've been called from some other interrupt routine
+        * but who knows what strange things coders get up to!
+        *
+        * If the interrupt routine is currently running, wait for it to
+        * finish, unless we appear to have been called via the interrupt
+        * routine.
+        */
+       while (devpriv->intr_running &&
+                       devpriv->intr_cpuid != THISCPU) {
+               comedi_spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
+               comedi_spin_lock_irqsave(&devpriv->ao_spinlock, flags);
+       }
+       comedi_spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
+       /* Reconfigure DAC for insn_write usage. */
+       outw(0, dev->iobase + PCI224_DACCEN);   /* Disable channels. */
+       devpriv->daccon = COMBINE(devpriv->daccon,
+                       PCI224_DACCON_TRIG_SW | PCI224_DACCON_FIFOINTR_EMPTY,
+                       PCI224_DACCON_TRIG_MASK | PCI224_DACCON_FIFOINTR_MASK);
+       outw(devpriv->daccon | PCI224_DACCON_FIFORESET,
+                       dev->iobase + PCI224_DACCON);
+       /* No longer running AO command. */
+       devpriv->ao_cmd_running = 0;
+}
+
+/*
+ * Handles start of acquisition for the AO subdevice.
+ */
+static void
+pci224_ao_start(comedi_device *dev, comedi_subdevice *s)
+{
+       comedi_cmd *cmd = &s->async->cmd;
+       unsigned long flags;
+
+       if (!devpriv->ao_stop_continuous && devpriv->ao_stop_count == 0) {
+               /* An empty acquisition! */
+               pci224_ao_stop(dev, s);
+               s->async->events |= COMEDI_CB_EOA;
+               comedi_event(dev, s, s->async->events);
+       } else {
+               /* Enable interrupts. */
+               comedi_spin_lock_irqsave(&devpriv->ao_spinlock, flags);
+               if (cmd->stop_src == TRIG_EXT) {
+                       devpriv->intsce = PCI224_INTR_EXT | PCI224_INTR_DAC;
+               } else {
+                       devpriv->intsce = PCI224_INTR_DAC;
+               }
+               outb(devpriv->intsce, devpriv->iobase1 + PCI224_INT_SCE);
+               comedi_spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
+       }
+}
+
+/*
+ * Handles interrupts from the DAC FIFO.
+ */
+static void
+pci224_ao_handle_fifo(comedi_device *dev, comedi_subdevice *s)
+{
+       comedi_cmd *cmd = &s->async->cmd;
+       unsigned int num_scans;
+       unsigned int room;
+       unsigned short dacstat;
+       unsigned int i, n;
+       unsigned int bytes_per_scan;
+
+       if (cmd->chanlist_len) {
+               bytes_per_scan = cmd->chanlist_len * sizeof(sampl_t);
+       } else {
+               /* Shouldn't get here! */
+               bytes_per_scan = sizeof(sampl_t);
+       }
+       /* Determine number of scans available in buffer. */
+       num_scans = comedi_buf_read_n_available(s) / bytes_per_scan;
+       if (!devpriv->ao_stop_continuous) {
+               /* Fixed number of scans. */
+               if (num_scans > devpriv->ao_stop_count) {
+                       num_scans = devpriv->ao_stop_count;
+               }
+       }
+
+       /* Determine how much room is in the FIFO (in samples). */
+       dacstat = inw(dev->iobase + PCI224_DACCON);
+       switch (dacstat & PCI224_DACCON_FIFOFL_MASK) {
+       case PCI224_DACCON_FIFOFL_EMPTY:
+               room = PCI224_FIFO_ROOM_EMPTY;
+               if (!devpriv->ao_stop_continuous &&
+                               devpriv->ao_stop_count == 0) {
+                       /* FIFO empty at end of counted acquisition. */
+                       pci224_ao_stop(dev, s);
+                       s->async->events |= COMEDI_CB_EOA;
+               }
+               break;
+       case PCI224_DACCON_FIFOFL_ONETOHALF:
+               room = PCI224_FIFO_ROOM_ONETOHALF;
+               break;
+       case PCI224_DACCON_FIFOFL_HALFTOFULL:
+               room = PCI224_FIFO_ROOM_HALFTOFULL;
+               break;
+       default:
+               room = PCI224_FIFO_ROOM_FULL;
+               break;
+       }
+       if (devpriv->ao_cmd_running) {
+               if (room >= PCI224_FIFO_ROOM_ONETOHALF) {
+                       /* FIFO is less than half-full. */
+                       if (num_scans == 0) {
+                               /* Nothing left to put in the FIFO. */
+                               pci224_ao_stop(dev, s);
+                               s->async->events |= COMEDI_CB_OVERFLOW;
+                               rt_printk(KERN_ERR "comedi%d: "
+                                               "AO buffer underrun\n",
+                                               dev->minor);
+                       }
+               }
+               /* Determine how many new scans can be put in the FIFO. */
+               if (cmd->chanlist_len) {
+                       room /= cmd->chanlist_len;
+               }
+               /* Determine how many scans to process. */
+               if (num_scans > room) {
+                       num_scans = room;
+               }
+               /* Process scans. */
+               for (n = 0; n < num_scans; n++) {
+                       cfc_read_array_from_buffer(s, &devpriv->ao_scan_vals[0],
+                                       bytes_per_scan);
+                       for (i = 0; i < cmd->chanlist_len; i++) {
+                               outw(devpriv->ao_scan_vals[devpriv->ao_scan_order[i]],
+                                               dev->iobase + PCI224_DACDATA);
+                       }
+               }
+               if (!devpriv->ao_stop_continuous) {
+                       devpriv->ao_stop_count -= num_scans;
+                       if (devpriv->ao_stop_count == 0) {
+                               /*
+                                * Change FIFO interrupt trigger level to wait
+                                * until FIFO is empty.
+                                */
+                               devpriv->daccon = COMBINE(devpriv->daccon,
+                                               PCI224_DACCON_FIFOINTR_EMPTY,
+                                               PCI224_DACCON_FIFOINTR_MASK);
+                               outw(devpriv->daccon,
+                                               dev->iobase + PCI224_DACCON);
+                       }
+               }
+               if ((devpriv->daccon & PCI224_DACCON_TRIG_MASK) ==
+                               PCI224_DACCON_TRIG_NONE) {
+                       unsigned short trig;
+
+                       /*
+                        * This is the initial DAC FIFO interrupt at the
+                        * start of the acquisition.  The DAC's scan trigger
+                        * has been set to 'none' up until now.
+                        *
+                        * Now that data has been written to the FIFO, the
+                        * DAC's scan trigger source can be set to the
+                        * correct value.
+                        *
+                        * BUG: The first scan will be triggered immediately
+                        * if the scan trigger source is at logic level 1.
+                        */
+                       if (cmd->scan_begin_src == TRIG_TIMER) {
+                               trig = PCI224_DACCON_TRIG_Z2CT0;
+                       } else {
+                               /* cmd->scan_begin_src == TRIG_EXT */
+                               if (cmd->scan_begin_arg & CR_INVERT) {
+                                       trig = PCI224_DACCON_TRIG_EXTN;
+                               } else {
+                                       trig = PCI224_DACCON_TRIG_EXTP;
+                               }
+                       }
+                       devpriv->daccon = COMBINE(devpriv->daccon, trig,
+                                       PCI224_DACCON_TRIG_MASK);
+                       outw(devpriv->daccon, dev->iobase + PCI224_DACCON);
+               }
+       }
+       if (s->async->events) {
+               comedi_event(dev, s, s->async->events);
+       }
+}
+
+/*
+ * Internal trigger function to start acquisition on AO subdevice.
+ */
+static int
+pci224_ao_inttrig_start(comedi_device *dev, comedi_subdevice *s,
+               unsigned int trignum)
+{
+       unsigned long flags;
+
+       if (trignum != 0) return -EINVAL;
+
+       comedi_spin_lock_irqsave(&devpriv->ao_spinlock, flags);
+       if (s->async->inttrig) {
+               s->async->inttrig = NULLFUNC;
+               comedi_spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
+               if (devpriv->ao_cmd_running) {
+                       pci224_ao_start(dev, s);
+               }
+       } else {
+               comedi_spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
+       }
+
+       return 1;
+}
+
+#define MAX_SCAN_PERIOD                0xFFFFFFFFU
+#define MIN_SCAN_PERIOD                2500
+#define CONVERT_PERIOD         625
+
+/*
+ * 'do_cmdtest' function for AO subdevice.
+ */
+static int
+pci224_ao_cmdtest(comedi_device *dev, comedi_subdevice *s, comedi_cmd *cmd)
+{
+       int err = 0;
+       unsigned int tmp;
+
+       /* Step 1: make sure trigger sources are trivially valid. */
+
+       tmp = cmd->start_src;
+       cmd->start_src &= TRIG_INT | TRIG_EXT;
+       if (!cmd->start_src || tmp != cmd->start_src) err++;
+
+       tmp = cmd->scan_begin_src;
+       cmd->scan_begin_src &= TRIG_EXT | TRIG_TIMER;
+       if (!cmd->scan_begin_src || tmp != cmd->scan_begin_src) err++;
+
+       tmp = cmd->convert_src;
+       cmd->convert_src &= TRIG_NOW;
+       if (!cmd->convert_src || tmp != cmd->convert_src) err++;
+
+       tmp = cmd->scan_end_src;
+       cmd->scan_end_src &= TRIG_COUNT;
+       if (!cmd->scan_end_src || tmp != cmd->scan_end_src) err++;
+
+       tmp = cmd->stop_src;
+       cmd->stop_src &= TRIG_COUNT | TRIG_EXT | TRIG_NONE;
+       if (!cmd->stop_src || tmp != cmd->stop_src) err++;
+
+       if (err) return 1;
+
+       /* Step 2: make sure trigger sources are unique and mutually
+        * compatible. */
+
+       /* these tests are true if more than one _src bit is set */
+       if ((cmd->start_src & (cmd->start_src - 1)) != 0) err++;
+       if ((cmd->scan_begin_src & (cmd->scan_begin_src - 1)) != 0) err++;
+       if ((cmd->convert_src & (cmd->convert_src - 1)) != 0) err++;
+       if ((cmd->scan_end_src & (cmd->scan_end_src - 1)) != 0) err++;
+       if ((cmd->stop_src & (cmd->stop_src - 1)) != 0) err++;
+
+       /* There's only one external trigger signal (which makes these
+        * tests easier).  Only one thing can use it. */
+       tmp = 0;
+       if (cmd->start_src & TRIG_EXT) tmp++;
+       if (cmd->scan_begin_src & TRIG_EXT) tmp++;
+       if (cmd->stop_src & TRIG_EXT) tmp++;
+       if (tmp > 1) err++;
+
+       if (err) return 2;
+
+       /* Step 3: make sure arguments are trivially compatible. */
+
+       switch (cmd->start_src) {
+       case TRIG_INT:
+               if (cmd->start_arg != 0) {
+                       cmd->start_arg = 0;
+                       err++;
+               }
+               break;
+       case TRIG_EXT:
+               /* Force to external trigger 0. */
+               if ((cmd->start_arg & ~CR_FLAGS_MASK) != 0) {
+                       cmd->start_arg = COMBINE(cmd->start_arg, 0,
+                                       ~CR_FLAGS_MASK);
+                       err++;
+               }
+               /* The only flag allowed is CR_EDGE, which is ignored. */
+               if ((cmd->start_arg & CR_FLAGS_MASK & ~CR_EDGE) != 0) {
+                       cmd->start_arg = COMBINE(cmd->start_arg, 0,
+                                       CR_FLAGS_MASK & ~CR_EDGE);
+               }
+               break;
+       }
+
+       switch (cmd->scan_begin_src) {
+       case TRIG_TIMER:
+               if (cmd->scan_begin_arg > MAX_SCAN_PERIOD) {
+                       cmd->scan_begin_arg = MAX_SCAN_PERIOD;
+                       err++;
+               }
+               tmp = cmd->chanlist_len * CONVERT_PERIOD;
+               if (tmp < MIN_SCAN_PERIOD) {
+                       tmp = MIN_SCAN_PERIOD;
+               }
+               if (cmd->scan_begin_arg < tmp) {
+                       cmd->scan_begin_arg = tmp;
+                       err++;
+               }
+               break;
+       case TRIG_EXT:
+               /* Force to external trigger 0. */
+               if ((cmd->scan_begin_arg & ~CR_FLAGS_MASK) != 0) {
+                       cmd->scan_begin_arg = COMBINE(cmd->scan_begin_arg, 0,
+                                       ~CR_FLAGS_MASK);
+                       err++;
+               }
+               /* Only allow flags CR_EDGE and CR_INVERT.  Ignore CR_EDGE. */
+               if ((cmd->scan_begin_arg & CR_FLAGS_MASK &
+                                       ~(CR_EDGE | CR_INVERT)) != 0) {
+                       cmd->scan_begin_arg = COMBINE(cmd->scan_begin_arg, 0,
+                                       CR_FLAGS_MASK & ~(CR_EDGE | CR_INVERT));
+               }
+               break;
+       }
+
+       /* cmd->convert_src == TRIG_NOW */
+       if (cmd->convert_arg != 0) {
+               cmd->convert_arg = 0;
+               err++;
+       }
+
+       /* cmd->scan_end_arg == TRIG_COUNT */
+       if (cmd->scan_end_arg != cmd->chanlist_len) {
+               cmd->scan_end_arg = cmd->chanlist_len;
+               err++;
+       }
+
+       switch (cmd->stop_src) {
+       case TRIG_COUNT:
+               /* Any count allowed. */
+               break;
+       case TRIG_EXT:
+               /* Force to external trigger 0. */
+               if ((cmd->stop_arg & ~CR_FLAGS_MASK) != 0) {
+                       cmd->stop_arg = COMBINE(cmd->stop_arg, 0,
+                                       ~CR_FLAGS_MASK);
+                       err++;
+               }
+               /* The only flag allowed is CR_EDGE, which is ignored. */
+               if ((cmd->stop_arg & CR_FLAGS_MASK & ~CR_EDGE) != 0) {
+                       cmd->stop_arg = COMBINE(cmd->stop_arg, 0,
+                                       CR_FLAGS_MASK & ~CR_EDGE);
+               }
+               break;
+       case TRIG_NONE:
+               if (cmd->stop_arg != 0) {
+                       cmd->stop_arg = 0;
+                       err++;
+               }
+               break;
+       }
+
+       if (err) return 3;
+
+       /* Step 4: fix up any arguments. */
+
+       if (cmd->scan_begin_src == TRIG_TIMER) {
+               unsigned int div1, div2, round;
+               int round_mode = cmd->flags & TRIG_ROUND_MASK;
+
+               tmp = cmd->scan_begin_arg;
+               /* Check whether to use a single timer. */
+               switch (round_mode) {
+               case TRIG_ROUND_NEAREST:
+               default:
+                       round = TIMEBASE_10MHZ / 2;
+                       break;
+               case TRIG_ROUND_DOWN:
+                       round = 0;
+                       break;
+               case TRIG_ROUND_UP:
+                       round = TIMEBASE_10MHZ - 1;
+                       break;
+               }
+               /* Be careful to avoid overflow! */
+               div2 = cmd->scan_begin_arg / TIMEBASE_10MHZ;
+               div2 += (round + cmd->scan_begin_arg % TIMEBASE_10MHZ) /
+                       TIMEBASE_10MHZ;
+               if (div2 <= 0x10000) {
+                       /* A single timer will suffice. */
+                       if (div2 < 2) div2 = 2;
+                       cmd->scan_begin_arg = div2 * TIMEBASE_10MHZ;
+                       if (cmd->scan_begin_arg < div2 ||
+                                       cmd->scan_begin_arg < TIMEBASE_10MHZ) {
+                               /* Overflow! */
+                               cmd->scan_begin_arg = MAX_SCAN_PERIOD;
+                       }
+               } else {
+                       /* Use two timers. */
+                       div1 = devpriv->cached_div1;
+                       div2 = devpriv->cached_div2;
+                       pci224_cascade_ns_to_timer(TIMEBASE_10MHZ, &div1, &div2,
+                                       &cmd->scan_begin_arg, round_mode);
+                       devpriv->cached_div1 = div1;
+                       devpriv->cached_div2 = div2;
+               }
+               if (tmp != cmd->scan_begin_arg) {
+                       err++;
+               }
+       }
+
+       if (err) return 4;
+
+       /* Step 5: check channel list. */
+
+       if (cmd->chanlist && cmd->chanlist_len > 0) {
+               unsigned int range;
+               enum { range_err = 1, dupchan_err = 2, };
+               unsigned errors;
+               unsigned int n;
+               unsigned int ch;
+
+               /*
+                * Check all channels have the same range index.  Don't care
+                * about analogue reference, as we can't configure it.
+                *
+                * Check the list has no duplicate channels.
+                */
+               range = CR_RANGE(cmd->chanlist[0]);
+               errors = 0;
+               tmp = 0;
+               for (n = 0; n < cmd->chanlist_len; n++) {
+                       ch = CR_CHAN(cmd->chanlist[n]);
+                       if (tmp & (1U << ch)) {
+                               errors |= dupchan_err;
+                       }
+                       tmp |= (1U << ch);
+                       if (CR_RANGE(cmd->chanlist[n]) != range) {
+                               errors |= range_err;
+                       }
+               }
+               if (errors) {
+                       if (errors & dupchan_err) {
+                               comedi_error(dev, "entries in chanlist must "
+                                               "contain no duplicate "
+                                               "channels\n");
+                       }
+                       if (errors & range_err) {
+                               comedi_error(dev, "entries in chanlist must "
+                                               "all have the same range "
+                                               "index\n");
+                       }
+                       err++;
+               }
+       } else {
+               /* cmd->chanlist == NULL || cmd->chanlist_len == 0 */
+               err++;
+       }
+
+       if (err) return 5;
+
+       return 0;
+}
+
+/*
+ * 'do_cmd' function for AO subdevice.
+ */
+static int
+pci224_ao_cmd(comedi_device *dev, comedi_subdevice *s)
+{
+       comedi_cmd *cmd = &s->async->cmd;
+       int range;
+       unsigned int i, j;
+       unsigned int ch;
+       unsigned int rank;
+       unsigned long flags;
+
+       /* Cannot handle null/empty chanlist. */
+       if (cmd->chanlist == NULL || cmd->chanlist_len == 0) {
+               return -EINVAL;
+       }
+
+       devpriv->ao_cmd_running = 1;
+
+       /* Determine which channels are enabled and their load order.  */
+       devpriv->ao_enab = 0;
+
+       for (i = 0; i < cmd->chanlist_len; i++) {
+               ch = CR_CHAN(cmd->chanlist[i]);
+               devpriv->ao_enab |= 1U << ch;
+               rank = 0;
+               for (j = 0; j < cmd->chanlist_len; j++) {
+                       if (CR_CHAN(cmd->chanlist[j]) < ch) {
+                               rank++;
+                       }
+               }
+               devpriv->ao_scan_order[rank] = i;
+       }
+
+       /* Set enabled channels. */
+       outw(devpriv->ao_enab, dev->iobase + PCI224_DACCEN);
+
+       /* Determine range and polarity.  All channels the same.  */
+       range = CR_RANGE(cmd->chanlist[0]);
+
+       /*
+        * Set DAC range and polarity.
+        * Set DAC scan trigger source to 'none'.
+        * Set DAC FIFO interrupt trigger level to 'not half full'.
+        * Reset DAC FIFO.
+        *
+        * N.B. DAC FIFO interrupts are currently disabled.
+        */
+       devpriv->daccon = COMBINE(devpriv->daccon,
+                       (devpriv->hwrange[range] | PCI224_DACCON_TRIG_NONE |
+                        PCI224_DACCON_FIFOINTR_NHALF),
+                       (PCI224_DACCON_POLAR_MASK | PCI224_DACCON_VREF_MASK |
+                        PCI224_DACCON_TRIG_MASK | PCI224_DACCON_FIFOINTR_MASK));
+       outw(devpriv->daccon | PCI224_DACCON_FIFORESET,
+                       dev->iobase + PCI224_DACCON);
+
+       if (cmd->scan_begin_src == TRIG_TIMER) {
+               unsigned int div1, div2, round;
+               unsigned int ns = cmd->scan_begin_arg;
+               int round_mode = cmd->flags & TRIG_ROUND_MASK;
+
+               /* Check whether to use a single timer. */
+               switch (round_mode) {
+               case TRIG_ROUND_NEAREST:
+               default:
+                       round = TIMEBASE_10MHZ / 2;
+                       break;
+               case TRIG_ROUND_DOWN:
+                       round = 0;
+                       break;
+               case TRIG_ROUND_UP:
+                       round = TIMEBASE_10MHZ - 1;
+                       break;
+               }
+               /* Be careful to avoid overflow! */
+               div2 = cmd->scan_begin_arg / TIMEBASE_10MHZ;
+               div2 += (round + cmd->scan_begin_arg % TIMEBASE_10MHZ) /
+                       TIMEBASE_10MHZ;
+               if (div2 <= 0x10000) {
+                       /* A single timer will suffice. */
+                       if (div2 < 2) div2 = 2;
+                       div2 &= 0xffff;
+                       div1 = 1;       /* Flag that single timer to be used. */
+               } else {
+                       /* Use two timers. */
+                       div1 = devpriv->cached_div1;
+                       div2 = devpriv->cached_div2;
+                       pci224_cascade_ns_to_timer(TIMEBASE_10MHZ, &div1, &div2,
+                                       &ns, round_mode);
+               }
+
+               /*
+                * The output of timer Z2-0 will be used as the scan trigger
+                * source.
+                */
+               /* Make sure Z2-0 is gated on.  */
+               outb(GAT_CONFIG(0, GAT_VCC),
+                               devpriv->iobase1 + PCI224_ZGAT_SCE);
+               if (div1 == 1) {
+                       /* Not cascading.  Z2-0 needs 10 MHz clock. */
+                       outb(CLK_CONFIG(0, CLK_10MHZ),
+                                       devpriv->iobase1 + PCI224_ZCLK_SCE);
+               } else {
+                       /* Cascading with Z2-2. */
+                       /* Make sure Z2-2 is gated on.  */
+                       outb(GAT_CONFIG(2, GAT_VCC),
+                                       devpriv->iobase1 + PCI224_ZGAT_SCE);
+                       /* Z2-2 needs 10 MHz clock. */
+                       outb(CLK_CONFIG(2, CLK_10MHZ),
+                                       devpriv->iobase1 + PCI224_ZCLK_SCE);
+                       /* Load Z2-2 mode (2) and counter (div1). */
+                       i8254_load(devpriv->iobase1 + PCI224_Z2_CT0,
+                                       2, div1, 2);
+                       /* Z2-0 is clocked from Z2-2's output. */
+                       outb(CLK_CONFIG(0, CLK_OUTNM1),
+                                       devpriv->iobase1 + PCI224_ZCLK_SCE);
+               }
+               /* Load Z2-0 mode (2) and counter (div2). */
+               i8254_load(devpriv->iobase1 + PCI224_Z2_CT0, 0, div2, 2);
+       }
+
+       /*
+        * Sort out end of acquisition.
+        */
+       switch (cmd->stop_src) {
+       case TRIG_COUNT:
+               /* Fixed number of scans.  */
+               devpriv->ao_stop_continuous = 0;
+               devpriv->ao_stop_count = cmd->stop_arg;
+               break;
+       default:
+               /* Continuous scans. */
+               devpriv->ao_stop_continuous = 1;
+               devpriv->ao_stop_count = 0;
+               break;
+       }
+
+       /*
+        * Sort out start of acquisition.
+        */
+       switch (cmd->start_src) {
+       case TRIG_INT:
+               comedi_spin_lock_irqsave(&devpriv->ao_spinlock, flags);
+               s->async->inttrig = &pci224_ao_inttrig_start;
+               comedi_spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
+               break;
+       case TRIG_EXT:
+               /* Enable external interrupt trigger to start acquisition. */
+               comedi_spin_lock_irqsave(&devpriv->ao_spinlock, flags);
+               devpriv->intsce |= PCI224_INTR_EXT;
+               outb(devpriv->intsce, devpriv->iobase1 + PCI224_INT_SCE);
+               comedi_spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
+               break;
+       }
+
+       return 0;
+}
+
+/*
+ * 'cancel' function for AO subdevice.
+ */
+static int
+pci224_ao_cancel(comedi_device *dev, comedi_subdevice *s)
+{
+       if (devpriv->ao_cmd_running) {
+               pci224_ao_stop(dev, s);
+       }
+       return 0;
+}
+
+/*
+ * 'munge' data for AO command.
+ */
+static void
+pci224_ao_munge(comedi_device *dev, comedi_subdevice *s, void *data,
+               unsigned int num_bytes, unsigned int chan_index)
+{
+       comedi_async *async = s->async;
+       sampl_t *array = data;
+       unsigned int length = num_bytes / sizeof(*array);
+       unsigned int offset;
+       unsigned int shift;
+       unsigned int i;
+
+       /* The hardware expects 16-bit numbers. */
+       shift = 16 - thisboard->ao_bits;
+       /* Channels will be all bipolar or all unipolar. */
+       if ((devpriv->hwrange[CR_RANGE(async->cmd.chanlist[0])] &
+                               PCI224_DACCON_POLAR_MASK) ==
+                       PCI224_DACCON_POLAR_UNI) {
+               /* Unipolar */
+               offset = 0;
+       } else {
+               /* Bipolar */
+               offset = 32768;
+       }
+       /* Munge the data. */
+       for (i = 0; i < length; i++) {
+               array[i] = (array[i] << shift) - offset;
+       }
+}
+
+/*
+ * Interrupt handler.
+ */
+static irqreturn_t
+pci224_interrupt(int irq, void *d, struct pt_regs *regs)
+{
+       comedi_device *dev = d;
+       comedi_subdevice *s = &dev->subdevices[0];
+       comedi_cmd *cmd;
+       unsigned char intstat, valid_intstat;
+       unsigned char curenab;
+       int retval = 0;
+       unsigned long flags;
+
+       intstat = inb(devpriv->iobase1 + PCI224_INT_SCE) & 0x3F;
+       if (intstat) {
+               retval = 1;
+               comedi_spin_lock_irqsave(&devpriv->ao_spinlock, flags);
+               valid_intstat = devpriv->intsce & intstat;
+               /* Temporarily disable interrupt sources. */
+               curenab = devpriv->intsce & ~intstat;
+               outb(curenab, devpriv->iobase1 + PCI224_INT_SCE);
+               devpriv->intr_running = 1;
+               devpriv->intr_cpuid = THISCPU;
+               comedi_spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
+               if (s->async && devpriv->ao_cmd_running) {
+                       cmd = &s->async->cmd;
+                       if (valid_intstat & PCI224_INTR_EXT) {
+                               devpriv->intsce &= ~PCI224_INTR_EXT;
+                               if (cmd->start_src == TRIG_EXT) {
+                                       pci224_ao_start(dev, s);
+                               } else if (cmd->stop_src == TRIG_EXT) {
+                                       pci224_ao_stop(dev, s);
+                               }
+                       }
+                       if (valid_intstat & PCI224_INTR_DAC) {
+                               pci224_ao_handle_fifo(dev, s);
+                       }
+               }
+               /* Reenable interrupt sources. */
+               comedi_spin_lock_irqsave(&devpriv->ao_spinlock, flags);
+               if (curenab != devpriv->intsce) {
+                       outb(devpriv->intsce, devpriv->iobase1 + PCI224_INT_SCE);
+               }
+               devpriv->intr_running = 0;
+               comedi_spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
+       }
+       return IRQ_RETVAL(retval);
+}
+
+/*
+ * This function looks for a PCI device matching the requested board name,
+ * bus and slot.
+ */
+static int
+pci224_find_pci(comedi_device *dev, int bus, int slot,
+               struct pci_dev **pci_dev_p)
+{
+       struct pci_dev *pci_dev = NULL;
+       struct pci_device_id *pci_id;
+
+       *pci_dev_p = NULL;
+
+       /* Look for PCI table entry for this model. */
+       for (pci_id = pci224_pci_table; pci_id->vendor != 0; pci_id++) {
+               if (pci_id->driver_data == thisboard->model)
+                       break;
+       }
+       if (pci_id->vendor == 0) {
+               printk(KERN_ERR "comedi%d: %s: BUG! "
+                               "cannot determine board type!\n",
+                               dev->minor, DRIVER_NAME);
+               return -EINVAL;
+       }
+
+       /* Look for matching PCI device. */
+       for(pci_dev = pci_get_device(pci_id->vendor, pci_id->device, NULL);
+                       pci_dev != NULL ; 
+                       pci_dev = pci_get_device(pci_id->vendor,
+                               pci_id->device, pci_dev)) {
+               /* If bus/slot specified, check them. */
+               if (bus || slot) {
+                       if (bus != pci_dev->bus->number
+                                       || slot != PCI_SLOT(pci_dev->devfn))
+                               continue;
+               }
+#if 0
+               if (pci_id->subvendor != PCI_ANY_ID) {
+                       if (pci_dev->subsystem_vendor != pci_id->subvendor)
+                               continue;
+               }
+               if (pci_id->subdevice != PCI_ANY_ID) {
+                       if (pci_dev->subsystem_device != pci_id->subdevice)
+                               continue;
+               }
+#endif
+               if (((pci_dev->class ^ pci_id->class) & pci_id->class_mask) != 0)
+                       continue;
+
+               /* Found a match. */
+               *pci_dev_p = pci_dev;
+               return 0;
+       }
+       /* No match found. */
+       if (bus || slot) {
+               printk(KERN_ERR "comedi%d: error! "
+                               "no %s found at pci %02x:%02x!\n",
+                               dev->minor, thisboard->name,
+                               bus, slot);
+       } else {
+               printk(KERN_ERR "comedi%d: error! no %s found!\n",
+                               dev->minor, thisboard->name);
+       }
+       return -EIO;
+}
+
+/*
+ * This function checks and requests an I/O region, reporting an error
+ * if there is a conflict.
+ */
+static int
+pci224_request_region(unsigned minor, unsigned long from, unsigned long extent)
+{
+       if (check_region(from, extent) < 0) {
+               printk(KERN_ERR "comedi%d: I/O port conflict (%#lx,%lu)!\n",
+                               minor, from, extent);
+               return -EIO;
+       }
+       request_region(from, extent, DRIVER_NAME);
+       return 0;
+}
+
+/*
+ * 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
+pci224_attach(comedi_device *dev,comedi_devconfig *it)
+{
+       comedi_subdevice *s;
+       struct pci_dev *pci_dev;
+       int iobase1 = 0, iobase2 = 0,  irq = 0;
+       int bus = 0, slot = 0;
+       unsigned n;
+       int ret;
+
+       printk(KERN_DEBUG "comedi%d: %s: attach\n", dev->minor,
+                       DRIVER_NAME);
+
+       bus = it->options[0];
+       slot = it->options[1];
+
+       if ((ret=pci224_find_pci(dev, bus, slot, &pci_dev)) < 0)
+               return ret;
+
+       if ((ret=pci_enable_device(pci_dev)) < 0) {
+               printk(KERN_ERR "comedi%d: error! cannot enable PCI device!\n",
+                               dev->minor);
+               pci_dev_put(pci_dev);
+               return ret;
+       }
+       iobase1 = pci_resource_start(pci_dev, 2);
+       iobase2 = pci_resource_start(pci_dev, 3);
+       irq = pci_dev->irq;
+
+       if ((ret=alloc_private(dev,sizeof(pci224_private))) < 0) {
+               printk(KERN_ERR "comedi%d: error! out of memory!\n",
+                               dev->minor);
+               pci_dev_put(pci_dev);
+               return ret; 
+       }
+
+       devpriv->pci_dev = pci_dev;
+       spin_lock_init(&devpriv->ao_spinlock);
+
+       /* Allocate readback buffer for AO channels. */
+       devpriv->ao_readback = kmalloc(sizeof(devpriv->ao_readback[0]) *
+                       thisboard->ao_chans, GFP_KERNEL);
+       if (!devpriv->ao_readback) {
+               return -ENOMEM;
+       }
+
+       /* Allocate buffer to hold values for AO channel scan. */
+       devpriv->ao_scan_vals = kmalloc(sizeof(devpriv->ao_scan_vals[0]) *
+                       thisboard->ao_chans, GFP_KERNEL);
+       if (!devpriv->ao_scan_vals) {
+               return -ENOMEM;
+       }
+
+       /* Allocate buffer to hold AO channel scan order. */
+       devpriv->ao_scan_order = kmalloc(sizeof(devpriv->ao_scan_order[0]) *
+                       thisboard->ao_chans, GFP_KERNEL);
+       if (!devpriv->ao_scan_order) {
+               return -ENOMEM;
+       }
+
+       /* Reserve I/O space 1. */
+       ret = pci224_request_region(dev->minor, iobase1, PCI224_IO1_SIZE);
+       if (ret < 0) {
+               return ret;
+       }
+       devpriv->iobase1 = iobase1;
+
+       /* Reserve I/O space 2. */
+       ret = pci224_request_region(dev->minor, iobase2, PCI224_IO2_SIZE);
+       if (ret < 0) {
+               return ret;
+       }
+       dev->iobase = iobase2;
+
+       /* Disable interrupt sources. */
+       devpriv->intsce = 0;
+       outb(0, devpriv->iobase1 + PCI224_INT_SCE);
+
+       /* Initialize the DAC hardware. */
+       outw(PCI224_DACCON_GLOBALRESET, dev->iobase + PCI224_DACCON);
+       outw(0, dev->iobase + PCI224_DACCEN);
+       outw(0, dev->iobase + PCI224_FIFOSIZ);
+       devpriv->daccon = (PCI224_DACCON_TRIG_SW | PCI224_DACCON_POLAR_BI |
+                       PCI224_DACCON_FIFOENAB | PCI224_DACCON_FIFOINTR_EMPTY);
+       outw(devpriv->daccon | PCI224_DACCON_FIFORESET,
+                       dev->iobase + PCI224_DACCON);
+
+       /* Allocate subdevices.  There is only one!  */
+       if ((ret=alloc_subdevices(dev, 1)) < 0) {
+               printk(KERN_ERR "comedi%d: error! out of memory!\n",
+                               dev->minor);
+               return ret;
+       }
+
+       s = dev->subdevices + 0;
+       /* Analog output subdevice. */
+       s->type = COMEDI_SUBD_AO;
+       s->subdev_flags = SDF_WRITABLE | SDF_GROUND;
+       s->n_chan = thisboard->ao_chans;
+       s->maxdata = (1 << thisboard->ao_bits) - 1;
+       s->insn_write = &pci224_ao_insn_write;
+       s->insn_read = &pci224_ao_insn_read;
+       s->len_chanlist = s->n_chan;
+
+       dev->write_subdev = s;
+       s->do_cmd = &pci224_ao_cmd;
+       s->do_cmdtest = &pci224_ao_cmdtest;
+       s->cancel = &pci224_ao_cancel;
+       s->munge = &pci224_ao_munge;
+
+        /* Sort out channel range options. */
+        if (thisboard->model == pci234_model) {
+                /* PCI234 range options. */
+                s->range_table_list = kmalloc(
+                                sizeof(comedi_lrange *) * s->n_chan,
+                                GFP_KERNEL);
+                if (!s->range_table_list) {
+                        return -ENOMEM;
+                }
+               for (n = 2; n < 3 + s->n_chan; n++) {
+                       if (it->options[n] < 0 || it->options[n] > 1) {
+                               printk(KERN_WARNING "comedi%d: %s: warning! "
+                                               "bad options[%u]=%d\n",
+                                               dev->minor, DRIVER_NAME, n,
+                                               it->options[n]);
+                       }
+               }
+                for (n = 0; n < s->n_chan; n++) {
+                        if (n < COMEDI_NDEVCONFOPTS - 3 &&
+                                        it->options[3+n] == 1) {
+                                if (it->options[2] == 1) {
+                                        s->range_table_list[n] =
+                                                &range_pci234_ext;
+                                } else {
+                                        s->range_table_list[n] =
+                                                &range_bipolar5;
+                                }
+                        } else {
+                                if (it->options[2] == 1) {
+                                        s->range_table_list[n] =
+                                                &range_pci234_ext2;
+                                } else {
+                                        s->range_table_list[n] =
+                                                &range_bipolar10;
+                                }
+                        }
+                }
+                devpriv->hwrange = hwrange_pci234;
+        } else {
+                /* PCI224 range options. */
+                if (it->options[2] == 1) {
+                        s->range_table = &range_pci224_external;
+                        devpriv->hwrange = hwrange_pci224_external;
+                } else {
+                       if (it->options[2] != 0) {
+                               printk(KERN_WARNING "comedi%d: %s: warning! "
+                                               "bad options[2]=%d\n",
+                                               dev->minor, DRIVER_NAME,
+                                               it->options[2]);
+                       }
+                        s->range_table = &range_pci224_internal;
+                        devpriv->hwrange = hwrange_pci224_internal;
+                }
+        }
+
+       dev->board_name = thisboard->name;
+
+       if (irq) {
+               ret = comedi_request_irq(irq, pci224_interrupt, SA_SHIRQ,
+                               DRIVER_NAME, dev);
+               if (ret < 0) {
+                       printk(KERN_ERR "comedi%d: error! "
+                                       "unable to allocate irq %d\n",
+                                       dev->minor, irq);
+                       return ret;
+               } else {
+                       dev->irq = irq;
+               }
+       }
+
+       printk(KERN_INFO "comedi%d: %s ", dev->minor, dev->board_name);
+       printk("(pci %02x:%02x.%x) ", pci_dev->bus->number,
+                       PCI_SLOT(pci_dev->devfn),
+                       PCI_FUNC(pci_dev->devfn));
+       if (irq) {
+               printk("(irq %d%s) ", irq, (dev->irq ? "" : " UNAVAILABLE"));
+       } else {
+               printk("(no irq) ");
+       }
+       
+       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
+pci224_detach(comedi_device *dev)
+{
+       printk(KERN_DEBUG "comedi%d: %s: detach\n", dev->minor, DRIVER_NAME);
+
+       if (dev->irq) {
+               comedi_free_irq(dev->irq, dev);
+       }
+        if (dev->subdevices) {
+                comedi_subdevice *s;
+
+                s = dev->subdevices + 0;
+                /* AO subdevice */
+                if (s->range_table_list) {
+                        kfree(s->range_table_list);
+                }
+        }
+       if (dev->iobase) {
+               release_region(dev->iobase, PCI224_IO2_SIZE);
+       }
+       if (devpriv) {
+               if (devpriv->iobase1) {
+                       release_region(devpriv->iobase1, PCI224_IO1_SIZE);
+               }
+               if (devpriv->ao_readback) {
+                       kfree(devpriv->ao_readback);
+               }
+               if (devpriv->ao_scan_vals) {
+                       kfree(devpriv->ao_scan_vals);
+               }
+               if (devpriv->ao_scan_order) {
+                       kfree(devpriv->ao_scan_order);
+               }
+               if (devpriv->pci_dev) {
+                       pci_dev_put(devpriv->pci_dev);
+               }
+       }
+       if (dev->board_name) {
+               printk(KERN_INFO "comedi%d: %s removed\n",
+                               dev->minor, dev->board_name);
+       }
+       
+       return 0;
+}
+