staging: comedi: dac02: introduce comedi driver for DAC02 boards

This board is currently supported by the poc driver. That driver used
to support a number of simple boards but now only provides support for
the DAC02 board.

Introduce a new comedi driver specifically for the DAC02 board. This
allows cleaning up all the cruft.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/Kconfig

@@ -260,6 +260,14 @@ config COMEDI_RTI802
 	  To compile this driver as a module, choose M here: the module will be
 	  called rti802.
 
+config COMEDI_DAC02
+	tristate "Keithley Metrabyte DAC02 compatible ISA card support"
+	---help---
+	  Enable support for Keithley Metrabyte DAC02 compatible ISA cards.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called dac02.
+
 config COMEDI_DAS16M1
 	tristate "MeasurementComputing CIO-DAS16/M1DAS-16 ISA card support"
 	select COMEDI_8255

drivers/staging/comedi/drivers/Makefile

@@ -24,6 +24,7 @@ obj-$(CONFIG_COMEDI_PCL818)		+= pcl818.o
 obj-$(CONFIG_COMEDI_PCM3724)		+= pcm3724.o
 obj-$(CONFIG_COMEDI_RTI800)		+= rti800.o
 obj-$(CONFIG_COMEDI_RTI802)		+= rti802.o
+obj-$(CONFIG_COMEDI_DAC02)		+= dac02.o
 obj-$(CONFIG_COMEDI_DAS16M1)		+= das16m1.o
 obj-$(CONFIG_COMEDI_DAS08_ISA)		+= das08_isa.o
 obj-$(CONFIG_COMEDI_DAS16)		+= das16.o

drivers/staging/comedi/drivers/dac02.c

@@ -0,0 +1,172 @@
+/*
+ * dac02.c
+ * Comedi driver for DAC02 compatible boards
+ * Copyright (C) 2014 H Hartley Sweeten <hsweeten@visionengravers.com>
+ *
+ * Based on the poc driver
+ * Copyright (C) 2000 Frank Mori Hess <fmhess@users.sourceforge.net>
+ * Copyright (C) 2001 David A. Schleef <ds@schleef.org>
+ *
+ * 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: dac02
+ * Description: Comedi driver for DAC02 compatible boards
+ * Devices: (Keithley Metrabyte) DAC-02 [dac02]
+ * Author: H Hartley Sweeten <hsweeten@visionengravers.com>
+ * Updated: Tue, 11 Mar 2014 11:27:19 -0700
+ * Status: unknown
+ *
+ * Configuration options:
+ *	[0] - I/O port base
+ */
+
+#include <linux/module.h>
+
+#include "../comedidev.h"
+
+/*
+ * The output range is selected by jumpering pins on the I/O connector.
+ *
+ *	    Range      Chan #   Jumper pins        Output
+ *	-------------  ------  -------------  -----------------
+ *	   0 to 5V       0        21 to 22      24
+ *	                 1        15 to 16      18
+ *	   0 to 10V      0        20 to 22      24
+ *	                 1        14 to 16      18
+ *	    +/-5V        0        21 to 22      23
+ *	                 1        15 to 16      17
+ *	    +/-10V       0        20 to 22      23
+ *	                 1        14 to 16      17
+ *	  4 to 20mA      0        21 to 22      25
+ *	                 1        15 to 16      19
+ *	AC reference     0      In on pin 22    24 (2-quadrant)
+ *	                        In on pin 22    23 (4-quadrant)
+ *	                 1      In on pin 16    18 (2-quadrant)
+ *	                        In on pin 16    17 (4-quadrant)
+ */
+static const struct comedi_lrange das02_ao_ranges = {
+	6, {
+		UNI_RANGE(5),
+		UNI_RANGE(10),
+		BIP_RANGE(5),
+		BIP_RANGE(10),
+		RANGE_mA(4, 20),
+		RANGE_ext(0, 1)
+	}
+};
+
+struct dac02_private {
+	unsigned int ao_readback[2];
+};
+
+/*
+ * Register I/O map
+ */
+#define DAC02_AO_LSB(x)		(0x00 + ((x) * 2))
+#define DAC02_AO_MSB(x)		(0x01 + ((x) * 2))
+
+static int dac02_ao_insn_write(struct comedi_device *dev,
+			       struct comedi_subdevice *s,
+			       struct comedi_insn *insn,
+			       unsigned int *data)
+{
+	struct dac02_private *devpriv = dev->private;
+	unsigned int chan = CR_CHAN(insn->chanspec);
+	unsigned int range = CR_RANGE(insn->chanspec);
+	unsigned int val;
+	int i;
+
+	for (i = 0; i < insn->n; i++) {
+		val = data[i];
+
+		devpriv->ao_readback[chan] = val;
+
+		/*
+		 * Unipolar outputs are true binary encoding.
+		 * Bipolar outputs are complementary offset binary
+		 * (that is, 0 = +full scale, maxdata = -full scale).
+		 */
+		if (comedi_range_is_bipolar(s, range))
+			val = s->maxdata - val;
+
+		/*
+		 * DACs are double-buffered.
+		 * Write LSB then MSB to latch output.
+		 */
+		outb((val << 4) & 0xf0, dev->iobase + DAC02_AO_LSB(chan));
+		outb((val >> 4) & 0xff, dev->iobase + DAC02_AO_MSB(chan));
+	}
+
+	return insn->n;
+}
+
+static int dac02_ao_insn_read(struct comedi_device *dev,
+			      struct comedi_subdevice *s,
+			      struct comedi_insn *insn,
+			      unsigned int *data)
+{
+	struct dac02_private *devpriv = dev->private;
+	unsigned int chan = CR_CHAN(insn->chanspec);
+	int i;
+
+	for (i = 0; i < insn->n; i++)
+		data[i] = devpriv->ao_readback[chan];
+
+	return insn->n;
+}
+
+static int dac02_attach(struct comedi_device *dev, struct comedi_devconfig *it)
+{
+	struct dac02_private *devpriv;
+	struct comedi_subdevice *s;
+	int ret;
+
+	devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
+	if (!devpriv)
+		return -ENOMEM;
+
+	ret = comedi_request_region(dev, it->options[0], 0x08);
+	if (ret)
+		return ret;
+
+	ret = comedi_alloc_subdevices(dev, 1);
+	if (ret)
+		return ret;
+
+	/* Analog Output subdevice */
+	s = &dev->subdevices[0];
+	s->type		= COMEDI_SUBD_AO;
+	s->subdev_flags	= SDF_WRITABLE;
+	s->n_chan	= 2;
+	s->maxdata	= 0x0fff;
+	s->range_table	= &das02_ao_ranges;
+	s->insn_write	= dac02_ao_insn_write;
+	s->insn_read	= dac02_ao_insn_read;
+
+	return 0;
+}
+
+static struct comedi_driver dac02_driver = {
+	.driver_name	= "dac02",
+	.module		= THIS_MODULE,
+	.attach		= dac02_attach,
+	.detach		= comedi_legacy_detach,
+};
+module_comedi_driver(dac02_driver);
+
+MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
+MODULE_DESCRIPTION("Comedi driver for DAC02 compatible boards");
+MODULE_LICENSE("GPL");