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path: root/drivers/iio/dac/cio-dac.c
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Diffstat (limited to 'drivers/iio/dac/cio-dac.c')
-rw-r--r--drivers/iio/dac/cio-dac.c144
1 files changed, 144 insertions, 0 deletions
diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c
new file mode 100644
index 000000000000..5a743e2a779d
--- /dev/null
+++ b/drivers/iio/dac/cio-dac.c
@@ -0,0 +1,144 @@
+/*
+ * IIO driver for the Measurement Computing CIO-DAC
+ * Copyright (C) 2016 William Breathitt Gray
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * 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_array(base, uint, &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 16-bit value */
+ if ((unsigned int)val > 65535)
+ 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 = {
+ .driver_module = THIS_MODULE,
+ .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");