root/drivers/iio/dac/cio-dac.c

DEFINITIONS

1. cio_dac_read_raw
2. cio_dac_write_raw
3. cio_dac_probe

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * IIO driver for the Measurement Computing CIO-DAC
   4  * Copyright (C) 2016 William Breathitt Gray
   5  *
   6  * This driver supports the following Measurement Computing devices: CIO-DAC16,
   7  * CIO-DAC06, and PC104-DAC06.
   8  */
   9 #include <linux/bitops.h>
  10 #include <linux/device.h>
  11 #include <linux/errno.h>
  12 #include <linux/iio/iio.h>
  13 #include <linux/iio/types.h>
  14 #include <linux/io.h>
  15 #include <linux/ioport.h>
  16 #include <linux/isa.h>
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 
  20 #define CIO_DAC_NUM_CHAN 16
  21 
  22 #define CIO_DAC_CHAN(chan) {                            \
  23         .type = IIO_VOLTAGE,                            \
  24         .channel = chan,                                \
  25         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
  26         .indexed = 1,                                   \
  27         .output = 1                                     \
  28 }
  29 
  30 #define CIO_DAC_EXTENT 32
  31 
  32 static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)];
  33 static unsigned int num_cio_dac;
  34 module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
  35 MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
  36 
  37 /**
  38  * struct cio_dac_iio - IIO device private data structure
  39  * @chan_out_states:    channels' output states
  40  * @base:               base port address of the IIO device
  41  */
  42 struct cio_dac_iio {
  43         int chan_out_states[CIO_DAC_NUM_CHAN];
  44         unsigned int base;
  45 };
  46 
  47 static int cio_dac_read_raw(struct iio_dev *indio_dev,
  48         struct iio_chan_spec const *chan, int *val, int *val2, long mask)
  49 {
  50         struct cio_dac_iio *const priv = iio_priv(indio_dev);
  51 
  52         if (mask != IIO_CHAN_INFO_RAW)
  53                 return -EINVAL;
  54 
  55         *val = priv->chan_out_states[chan->channel];
  56 
  57         return IIO_VAL_INT;
  58 }
  59 
  60 static int cio_dac_write_raw(struct iio_dev *indio_dev,
  61         struct iio_chan_spec const *chan, int val, int val2, long mask)
  62 {
  63         struct cio_dac_iio *const priv = iio_priv(indio_dev);
  64         const unsigned int chan_addr_offset = 2 * chan->channel;
  65 
  66         if (mask != IIO_CHAN_INFO_RAW)
  67                 return -EINVAL;
  68 
  69         /* DAC can only accept up to a 16-bit value */
  70         if ((unsigned int)val > 65535)
  71                 return -EINVAL;
  72 
  73         priv->chan_out_states[chan->channel] = val;
  74         outw(val, priv->base + chan_addr_offset);
  75 
  76         return 0;
  77 }
  78 
  79 static const struct iio_info cio_dac_info = {
  80         .read_raw = cio_dac_read_raw,
  81         .write_raw = cio_dac_write_raw
  82 };
  83 
  84 static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
  85         CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
  86         CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
  87         CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
  88         CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
  89 };
  90 
  91 static int cio_dac_probe(struct device *dev, unsigned int id)
  92 {
  93         struct iio_dev *indio_dev;
  94         struct cio_dac_iio *priv;
  95         unsigned int i;
  96 
  97         indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
  98         if (!indio_dev)
  99                 return -ENOMEM;
 100 
 101         if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
 102                 dev_name(dev))) {
 103                 dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n",
 104                         base[id], base[id] + CIO_DAC_EXTENT);
 105                 return -EBUSY;
 106         }
 107 
 108         indio_dev->info = &cio_dac_info;
 109         indio_dev->modes = INDIO_DIRECT_MODE;
 110         indio_dev->channels = cio_dac_channels;
 111         indio_dev->num_channels = CIO_DAC_NUM_CHAN;
 112         indio_dev->name = dev_name(dev);
 113         indio_dev->dev.parent = dev;
 114 
 115         priv = iio_priv(indio_dev);
 116         priv->base = base[id];
 117 
 118         /* initialize DAC outputs to 0V */
 119         for (i = 0; i < 32; i += 2)
 120                 outw(0, base[id] + i);
 121 
 122         return devm_iio_device_register(dev, indio_dev);
 123 }
 124 
 125 static struct isa_driver cio_dac_driver = {
 126         .probe = cio_dac_probe,
 127         .driver = {
 128                 .name = "cio-dac"
 129         }
 130 };
 131 
 132 module_isa_driver(cio_dac_driver, num_cio_dac);
 133 
 134 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
 135 MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver");
 136 MODULE_LICENSE("GPL v2");