1 files changed, 135 insertions, 0 deletions
diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c
new file mode 100644
index 000000000..77a6916b3
--- /dev/null
+++ b/drivers/iio/dac/cio-dac.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * IIO driver for the Measurement Computing CIO-DAC
+ * Copyright (C) 2016 William Breathitt Gray
+ *
+ * This driver supports the following Measurement Computing devices: CIO-DAC16,
+ * CIO-DAC06, and PC104-DAC06.
+ */
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/types.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/isa.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+
+#define CIO_DAC_NUM_CHAN 16
+
+#define CIO_DAC_CHAN(chan) {				\
+	.type = IIO_VOLTAGE,				\
+	.channel = chan,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
+	.indexed = 1,					\
+	.output = 1					\
+}
+
+#define CIO_DAC_EXTENT 32
+
+static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)];
+static unsigned int num_cio_dac;
+module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
+MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
+
+/**
+ * struct cio_dac_iio - IIO device private data structure
+ * @chan_out_states:	channels' output states
+ * @base:		base port address of the IIO device
+ */
+struct cio_dac_iio {
+	int chan_out_states[CIO_DAC_NUM_CHAN];
+	unsigned int base;
+};
+
+static int cio_dac_read_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
+{
+	struct cio_dac_iio *const priv = iio_priv(indio_dev);
+
+	if (mask != IIO_CHAN_INFO_RAW)
+		return -EINVAL;
+
+	*val = priv->chan_out_states[chan->channel];
+
+	return IIO_VAL_INT;
+}
+
+static int cio_dac_write_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *chan, int val, int val2, long mask)
+{
+	struct cio_dac_iio *const priv = iio_priv(indio_dev);
+	const unsigned int chan_addr_offset = 2 * chan->channel;
+
+	if (mask != IIO_CHAN_INFO_RAW)
+		return -EINVAL;
+
+	/* DAC can only accept up to a 12-bit value */
+	if ((unsigned int)val > 4095)
+		return -EINVAL;
+
+	priv->chan_out_states[chan->channel] = val;
+	outw(val, priv->base + chan_addr_offset);
+
+	return 0;
+}
+
+static const struct iio_info cio_dac_info = {
+	.read_raw = cio_dac_read_raw,
+	.write_raw = cio_dac_write_raw
+};
+
+static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
+	CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
+	CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
+	CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
+	CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
+};
+
+static int cio_dac_probe(struct device *dev, unsigned int id)
+{
+	struct iio_dev *indio_dev;
+	struct cio_dac_iio *priv;
+	unsigned int i;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
+		dev_name(dev))) {
+		dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n",
+			base[id], base[id] + CIO_DAC_EXTENT);
+		return -EBUSY;
+	}
+
+	indio_dev->info = &cio_dac_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = cio_dac_channels;
+	indio_dev->num_channels = CIO_DAC_NUM_CHAN;
+	indio_dev->name = dev_name(dev);
+
+	priv = iio_priv(indio_dev);
+	priv->base = base[id];
+
+	/* initialize DAC outputs to 0V */
+	for (i = 0; i < 32; i += 2)
+		outw(0, base[id] + i);
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static struct isa_driver cio_dac_driver = {
+	.probe = cio_dac_probe,
+	.driver = {
+		.name = "cio-dac"
+	}
+};
+
+module_isa_driver(cio_dac_driver, num_cio_dac);
+
+MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
+MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver");
+MODULE_LICENSE("GPL v2");