William Breathitt Gray | 3b8df5f | 2016-07-12 09:33:14 -0400 | [diff] [blame] | 1 | /* |
| 2 | * IIO driver for the Measurement Computing CIO-DAC |
| 3 | * Copyright (C) 2016 William Breathitt Gray |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License, version 2, as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, but |
| 10 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | * General Public License for more details. |
| 13 | * |
| 14 | * This driver supports the following Measurement Computing devices: CIO-DAC16, |
| 15 | * CIO-DAC06, and PC104-DAC06. |
| 16 | */ |
| 17 | #include <linux/bitops.h> |
| 18 | #include <linux/device.h> |
| 19 | #include <linux/errno.h> |
| 20 | #include <linux/iio/iio.h> |
| 21 | #include <linux/iio/types.h> |
| 22 | #include <linux/io.h> |
| 23 | #include <linux/ioport.h> |
| 24 | #include <linux/isa.h> |
| 25 | #include <linux/module.h> |
| 26 | #include <linux/moduleparam.h> |
| 27 | |
| 28 | #define CIO_DAC_NUM_CHAN 16 |
| 29 | |
| 30 | #define CIO_DAC_CHAN(chan) { \ |
| 31 | .type = IIO_VOLTAGE, \ |
| 32 | .channel = chan, \ |
| 33 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
| 34 | .indexed = 1, \ |
| 35 | .output = 1 \ |
| 36 | } |
| 37 | |
| 38 | #define CIO_DAC_EXTENT 32 |
| 39 | |
| 40 | static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)]; |
| 41 | static unsigned int num_cio_dac; |
| 42 | module_param_array(base, uint, &num_cio_dac, 0); |
| 43 | MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses"); |
| 44 | |
| 45 | /** |
| 46 | * struct cio_dac_iio - IIO device private data structure |
| 47 | * @chan_out_states: channels' output states |
| 48 | * @base: base port address of the IIO device |
| 49 | */ |
| 50 | struct cio_dac_iio { |
| 51 | int chan_out_states[CIO_DAC_NUM_CHAN]; |
| 52 | unsigned int base; |
| 53 | }; |
| 54 | |
| 55 | static int cio_dac_read_raw(struct iio_dev *indio_dev, |
| 56 | struct iio_chan_spec const *chan, int *val, int *val2, long mask) |
| 57 | { |
| 58 | struct cio_dac_iio *const priv = iio_priv(indio_dev); |
| 59 | |
| 60 | if (mask != IIO_CHAN_INFO_RAW) |
| 61 | return -EINVAL; |
| 62 | |
| 63 | *val = priv->chan_out_states[chan->channel]; |
| 64 | |
| 65 | return IIO_VAL_INT; |
| 66 | } |
| 67 | |
| 68 | static int cio_dac_write_raw(struct iio_dev *indio_dev, |
| 69 | struct iio_chan_spec const *chan, int val, int val2, long mask) |
| 70 | { |
| 71 | struct cio_dac_iio *const priv = iio_priv(indio_dev); |
| 72 | const unsigned int chan_addr_offset = 2 * chan->channel; |
| 73 | |
| 74 | if (mask != IIO_CHAN_INFO_RAW) |
| 75 | return -EINVAL; |
| 76 | |
| 77 | /* DAC can only accept up to a 16-bit value */ |
| 78 | if ((unsigned int)val > 65535) |
| 79 | return -EINVAL; |
| 80 | |
| 81 | priv->chan_out_states[chan->channel] = val; |
| 82 | outw(val, priv->base + chan_addr_offset); |
| 83 | |
| 84 | return 0; |
| 85 | } |
| 86 | |
| 87 | static const struct iio_info cio_dac_info = { |
| 88 | .driver_module = THIS_MODULE, |
| 89 | .read_raw = cio_dac_read_raw, |
| 90 | .write_raw = cio_dac_write_raw |
| 91 | }; |
| 92 | |
| 93 | static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = { |
| 94 | CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3), |
| 95 | CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7), |
| 96 | CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11), |
| 97 | CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15) |
| 98 | }; |
| 99 | |
| 100 | static int cio_dac_probe(struct device *dev, unsigned int id) |
| 101 | { |
| 102 | struct iio_dev *indio_dev; |
| 103 | struct cio_dac_iio *priv; |
| 104 | unsigned int i; |
| 105 | |
| 106 | indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); |
| 107 | if (!indio_dev) |
| 108 | return -ENOMEM; |
| 109 | |
| 110 | if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT, |
| 111 | dev_name(dev))) { |
| 112 | dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n", |
| 113 | base[id], base[id] + CIO_DAC_EXTENT); |
| 114 | return -EBUSY; |
| 115 | } |
| 116 | |
| 117 | indio_dev->info = &cio_dac_info; |
| 118 | indio_dev->modes = INDIO_DIRECT_MODE; |
| 119 | indio_dev->channels = cio_dac_channels; |
| 120 | indio_dev->num_channels = CIO_DAC_NUM_CHAN; |
| 121 | indio_dev->name = dev_name(dev); |
| 122 | |
| 123 | priv = iio_priv(indio_dev); |
| 124 | priv->base = base[id]; |
| 125 | |
| 126 | /* initialize DAC outputs to 0V */ |
| 127 | for (i = 0; i < 32; i += 2) |
| 128 | outw(0, base[id] + i); |
| 129 | |
| 130 | return devm_iio_device_register(dev, indio_dev); |
| 131 | } |
| 132 | |
| 133 | static struct isa_driver cio_dac_driver = { |
| 134 | .probe = cio_dac_probe, |
| 135 | .driver = { |
| 136 | .name = "cio-dac" |
| 137 | } |
| 138 | }; |
| 139 | |
| 140 | module_isa_driver(cio_dac_driver, num_cio_dac); |
| 141 | |
| 142 | MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); |
| 143 | MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver"); |
| 144 | MODULE_LICENSE("GPL v2"); |