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_hw_array(base, uint, ioport, &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 .read_raw = cio_dac_read_raw, 89 .write_raw = cio_dac_write_raw 90 }; 91 92 static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = { 93 CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3), 94 CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7), 95 CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11), 96 CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15) 97 }; 98 99 static int cio_dac_probe(struct device *dev, unsigned int id) 100 { 101 struct iio_dev *indio_dev; 102 struct cio_dac_iio *priv; 103 unsigned int i; 104 105 indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); 106 if (!indio_dev) 107 return -ENOMEM; 108 109 if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT, 110 dev_name(dev))) { 111 dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n", 112 base[id], base[id] + CIO_DAC_EXTENT); 113 return -EBUSY; 114 } 115 116 indio_dev->info = &cio_dac_info; 117 indio_dev->modes = INDIO_DIRECT_MODE; 118 indio_dev->channels = cio_dac_channels; 119 indio_dev->num_channels = CIO_DAC_NUM_CHAN; 120 indio_dev->name = dev_name(dev); 121 indio_dev->dev.parent = 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"); 145