drivers/staging/iio/adc/ad7298_core.c

   1 /*
   2  * AD7298 SPI ADC driver
   3  *
   4  * Copyright 2011 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2.
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/kernel.h>
  11 #include <linux/slab.h>
  12 #include <linux/sysfs.h>
  13 #include <linux/spi/spi.h>
  14 #include <linux/regulator/consumer.h>
  15 #include <linux/err.h>
  16 #include <linux/delay.h>
  17 #include <linux/module.h>
  18
  19 #include "../iio.h"
  20 #include "../sysfs.h"
  21 #include "../buffer_generic.h"
  22
  23 #include "ad7298.h"
  24
  25 static struct iio_chan_spec ad7298_channels[] = {
  26         IIO_CHAN(IIO_TEMP, 0, 1, 0, NULL, 0, 0,
  27                  (1 << IIO_CHAN_INFO_SCALE_SEPARATE),
  28                  9, AD7298_CH_TEMP, IIO_ST('s', 32, 32, 0), 0),
  29         IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 0, 0,
  30                  (1 << IIO_CHAN_INFO_SCALE_SHARED),
  31                  0, 0, IIO_ST('u', 12, 16, 0), 0),
  32         IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 1, 0,
  33                  (1 << IIO_CHAN_INFO_SCALE_SHARED),
  34                  1, 1, IIO_ST('u', 12, 16, 0), 0),
  35         IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 2, 0,
  36                  (1 << IIO_CHAN_INFO_SCALE_SHARED),
  37                  2, 2, IIO_ST('u', 12, 16, 0), 0),
  38         IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 3, 0,
  39                  (1 << IIO_CHAN_INFO_SCALE_SHARED),
  40                  3, 3, IIO_ST('u', 12, 16, 0), 0),
  41         IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 4, 0,
  42                  (1 << IIO_CHAN_INFO_SCALE_SHARED),
  43                  4, 4, IIO_ST('u', 12, 16, 0), 0),
  44         IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 5, 0,
  45                  (1 << IIO_CHAN_INFO_SCALE_SHARED),
  46                  5, 5, IIO_ST('u', 12, 16, 0), 0),
  47         IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 6, 0,
  48                  (1 << IIO_CHAN_INFO_SCALE_SHARED),
  49                  6, 6, IIO_ST('u', 12, 16, 0), 0),
  50         IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 7, 0,
  51                  (1 << IIO_CHAN_INFO_SCALE_SHARED),
  52                  7, 7, IIO_ST('u', 12, 16, 0), 0),
  53         IIO_CHAN_SOFT_TIMESTAMP(8),
  54 };
  55
  56 static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch)
  57 {
  58         int ret;
  59         st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref |
  60                                    (AD7298_CH(0) >> ch));
  61
  62         ret = spi_sync(st->spi, &st->scan_single_msg);
  63         if (ret)
  64                 return ret;
  65
  66         return be16_to_cpu(st->rx_buf[0]);
  67 }
  68
  69 static int ad7298_scan_temp(struct ad7298_state *st, int *val)
  70 {
  71         int tmp, ret;
  72
  73         tmp = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE |
  74                           AD7298_TAVG | st->ext_ref);
  75
  76         ret = spi_write(st->spi, (u8 *)&tmp, 2);
  77         if (ret)
  78                 return ret;
  79
  80         tmp = 0;
  81
  82         ret = spi_write(st->spi, (u8 *)&tmp, 2);
  83         if (ret)
  84                 return ret;
  85
  86         usleep_range(101, 1000); /* sleep > 100us */
  87
  88         ret = spi_read(st->spi, (u8 *)&tmp, 2);
  89         if (ret)
  90                 return ret;
  91
  92         tmp = be16_to_cpu(tmp) & RES_MASK(AD7298_BITS);
  93
  94         /*
  95          * One LSB of the ADC corresponds to 0.25 deg C.
  96          * The temperature reading is in 12-bit twos complement format
  97          */
  98
  99         if (tmp & (1 << (AD7298_BITS - 1))) {
 100                 tmp = (4096 - tmp) * 250;
 101                 tmp -= (2 * tmp);
 102
 103         } else {
 104                 tmp *= 250; /* temperature in milli degrees Celsius */
 105         }
 106
 107         *val = tmp;
 108
 109         return 0;
 110 }
 111
 112 static int ad7298_read_raw(struct iio_dev *dev_info,
 113                            struct iio_chan_spec const *chan,
 114                            int *val,
 115                            int *val2,
 116                            long m)
 117 {
 118         int ret;
 119         struct ad7298_state *st = iio_priv(dev_info);
 120         unsigned int scale_uv;
 121
 122         switch (m) {
 123         case 0:
 124                 mutex_lock(&dev_info->mlock);
 125                 if (iio_buffer_enabled(dev_info)) {
 126                         if (chan->address == AD7298_CH_TEMP)
 127                                 ret = -ENODEV;
 128                         else
 129                                 ret = ad7298_scan_from_ring(dev_info,
 130                                                             chan->address);
 131                 } else {
 132                         if (chan->address == AD7298_CH_TEMP)
 133                                 ret = ad7298_scan_temp(st, val);
 134                         else
 135                                 ret = ad7298_scan_direct(st, chan->address);
 136                 }
 137                 mutex_unlock(&dev_info->mlock);
 138
 139                 if (ret < 0)
 140                         return ret;
 141
 142                 if (chan->address != AD7298_CH_TEMP)
 143                         *val = ret & RES_MASK(AD7298_BITS);
 144
 145                 return IIO_VAL_INT;
 146         case (1 << IIO_CHAN_INFO_SCALE_SHARED):
 147                 scale_uv = (st->int_vref_mv * 1000) >> AD7298_BITS;
 148                 *val =  scale_uv / 1000;
 149                 *val2 = (scale_uv % 1000) * 1000;
 150                 return IIO_VAL_INT_PLUS_MICRO;
 151         case (1 << IIO_CHAN_INFO_SCALE_SEPARATE):
 152                 *val =  1;
 153                 *val2 = 0;
 154                 return IIO_VAL_INT_PLUS_MICRO;
 155         }
 156         return -EINVAL;
 157 }
 158
 159 static const struct iio_info ad7298_info = {
 160         .read_raw = &ad7298_read_raw,
 161         .driver_module = THIS_MODULE,
 162 };
 163
 164 static int __devinit ad7298_probe(struct spi_device *spi)
 165 {
 166         struct ad7298_platform_data *pdata = spi->dev.platform_data;
 167         struct ad7298_state *st;
 168         int ret;
 169         struct iio_dev *indio_dev = iio_allocate_device(sizeof(*st));
 170
 171         if (indio_dev == NULL)
 172                 return -ENOMEM;
 173
 174         st = iio_priv(indio_dev);
 175
 176         st->reg = regulator_get(&spi->dev, "vcc");
 177         if (!IS_ERR(st->reg)) {
 178                 ret = regulator_enable(st->reg);
 179                 if (ret)
 180                         goto error_put_reg;
 181         }
 182
 183         spi_set_drvdata(spi, indio_dev);
 184
 185         st->spi = spi;
 186
 187         indio_dev->name = spi_get_device_id(spi)->name;
 188         indio_dev->dev.parent = &spi->dev;
 189         indio_dev->modes = INDIO_DIRECT_MODE;
 190         indio_dev->channels = ad7298_channels;
 191         indio_dev->num_channels = ARRAY_SIZE(ad7298_channels);
 192         indio_dev->info = &ad7298_info;
 193
 194         /* Setup default message */
 195
 196         st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
 197         st->scan_single_xfer[0].len = 2;
 198         st->scan_single_xfer[0].cs_change = 1;
 199         st->scan_single_xfer[1].tx_buf = &st->tx_buf[1];
 200         st->scan_single_xfer[1].len = 2;
 201         st->scan_single_xfer[1].cs_change = 1;
 202         st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
 203         st->scan_single_xfer[2].len = 2;
 204
 205         spi_message_init(&st->scan_single_msg);
 206         spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
 207         spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
 208         spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);
 209
 210         if (pdata && pdata->vref_mv) {
 211                 st->int_vref_mv = pdata->vref_mv;
 212                 st->ext_ref = AD7298_EXTREF;
 213         } else {
 214                 st->int_vref_mv = AD7298_INTREF_mV;
 215         }
 216
 217         ret = ad7298_register_ring_funcs_and_init(indio_dev);
 218         if (ret)
 219                 goto error_disable_reg;
 220
 221         ret = iio_buffer_register(indio_dev,
 222                                   &ad7298_channels[1], /* skip temp0 */
 223                                   ARRAY_SIZE(ad7298_channels) - 1);
 224         if (ret)
 225                 goto error_cleanup_ring;
 226         ret = iio_device_register(indio_dev);
 227         if (ret)
 228                 goto error_unregister_ring;
 229
 230         return 0;
 231
 232 error_unregister_ring:
 233         iio_buffer_unregister(indio_dev);
 234 error_cleanup_ring:
 235         ad7298_ring_cleanup(indio_dev);
 236 error_disable_reg:
 237         if (!IS_ERR(st->reg))
 238                 regulator_disable(st->reg);
 239 error_put_reg:
 240         if (!IS_ERR(st->reg))
 241                 regulator_put(st->reg);
 242         iio_free_device(indio_dev);
 243
 244         return ret;
 245 }
 246
 247 static int __devexit ad7298_remove(struct spi_device *spi)
 248 {
 249         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 250         struct ad7298_state *st = iio_priv(indio_dev);
 251
 252         iio_buffer_unregister(indio_dev);
 253         ad7298_ring_cleanup(indio_dev);
 254         iio_device_unregister(indio_dev);
 255         if (!IS_ERR(st->reg)) {
 256                 regulator_disable(st->reg);
 257                 regulator_put(st->reg);
 258         }
 259         iio_device_unregister(indio_dev);
 260
 261         return 0;
 262 }
 263
 264 static const struct spi_device_id ad7298_id[] = {
 265         {"ad7298", 0},
 266         {}
 267 };
 268
 269 static struct spi_driver ad7298_driver = {
 270         .driver = {
 271                 .name   = "ad7298",
 272                 .bus    = &spi_bus_type,
 273                 .owner  = THIS_MODULE,
 274         },
 275         .probe          = ad7298_probe,
 276         .remove         = __devexit_p(ad7298_remove),
 277         .id_table       = ad7298_id,
 278 };
 279
 280 static int __init ad7298_init(void)
 281 {
 282         return spi_register_driver(&ad7298_driver);
 283 }
 284 module_init(ad7298_init);
 285
 286 static void __exit ad7298_exit(void)
 287 {
 288         spi_unregister_driver(&ad7298_driver);
 289 }
 290 module_exit(ad7298_exit);
 291
 292 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 293 MODULE_DESCRIPTION("Analog Devices AD7298 ADC");
 294 MODULE_LICENSE("GPL v2");
 295 MODULE_ALIAS("spi:ad7298");