drivers/staging/iio/adc/ad7887_core.c

   1 /*
   2  * AD7887 SPI ADC driver
   3  *
   4  * Copyright 2010-2011 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
  17 #include "../iio.h"
  18 #include "../sysfs.h"
  19 #include "../ring_generic.h"
  20 #include "adc.h"
  21
  22 #include "ad7887.h"
  23
  24 static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
  25 {
  26         int ret = spi_sync(st->spi, &st->msg[ch]);
  27         if (ret)
  28                 return ret;
  29
  30         return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
  31 }
  32
  33 static int ad7887_read_raw(struct iio_dev *dev_info,
  34                            struct iio_chan_spec const *chan,
  35                            int *val,
  36                            int *val2,
  37                            long m)
  38 {
  39         int ret;
  40         struct ad7887_state *st = iio_priv(dev_info);
  41         unsigned int scale_uv;
  42
  43         switch (m) {
  44         case 0:
  45                 mutex_lock(&dev_info->mlock);
  46                 if (iio_ring_enabled(dev_info))
  47                         ret = ad7887_scan_from_ring(st, 1 << chan->address);
  48                 else
  49                         ret = ad7887_scan_direct(st, chan->address);
  50                 mutex_unlock(&dev_info->mlock);
  51
  52                 if (ret < 0)
  53                         return ret;
  54                 *val = (ret >> st->chip_info->channel[0].scan_type.shift) &
  55                         RES_MASK(st->chip_info->channel[0].scan_type.realbits);
  56                 return IIO_VAL_INT;
  57         case (1 << IIO_CHAN_INFO_SCALE_SHARED):
  58                 scale_uv = (st->int_vref_mv * 1000)
  59                         >> st->chip_info->channel[0].scan_type.realbits;
  60                 *val =  scale_uv/1000;
  61                 *val2 = (scale_uv%1000)*1000;
  62                 return IIO_VAL_INT_PLUS_MICRO;
  63         }
  64         return -EINVAL;
  65 }
  66
  67
  68 static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
  69         /*
  70          * More devices added in future
  71          */
  72         [ID_AD7887] = {
  73                 .channel[0] = IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 1, 0,
  74                                        (1 << IIO_CHAN_INFO_SCALE_SHARED),
  75                                        1, 1, IIO_ST('u', 12, 16, 0), 0),
  76
  77                 .channel[1] = IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 0, 0,
  78                                        (1 << IIO_CHAN_INFO_SCALE_SHARED),
  79                                        0, 0, IIO_ST('u', 12, 16, 0), 0),
  80
  81                 .channel[2] = IIO_CHAN_SOFT_TIMESTAMP(2),
  82                 .int_vref_mv = 2500,
  83         },
  84 };
  85
  86 static const struct iio_info ad7887_info = {
  87         .read_raw = &ad7887_read_raw,
  88         .driver_module = THIS_MODULE,
  89 };
  90
  91 static int __devinit ad7887_probe(struct spi_device *spi)
  92 {
  93         struct ad7887_platform_data *pdata = spi->dev.platform_data;
  94         struct ad7887_state *st;
  95         int ret, voltage_uv = 0, regdone = 0;
  96         struct iio_dev *indio_dev = iio_allocate_device(sizeof(*st));
  97
  98         if (indio_dev == NULL)
  99                 return -ENOMEM;
 100
 101         st = iio_priv(indio_dev);
 102
 103         st->reg = regulator_get(&spi->dev, "vcc");
 104         if (!IS_ERR(st->reg)) {
 105                 ret = regulator_enable(st->reg);
 106                 if (ret)
 107                         goto error_put_reg;
 108
 109                 voltage_uv = regulator_get_voltage(st->reg);
 110         }
 111
 112         st->chip_info =
 113                 &ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 114
 115         spi_set_drvdata(spi, indio_dev);
 116         st->spi = spi;
 117
 118         /* Estabilish that the iio_dev is a child of the spi device */
 119         indio_dev->dev.parent = &spi->dev;
 120         indio_dev->name = spi_get_device_id(spi)->name;
 121         indio_dev->info = &ad7887_info;
 122         indio_dev->modes = INDIO_DIRECT_MODE;
 123
 124         /* Setup default message */
 125
 126         st->tx_cmd_buf[0] = AD7887_CH_AIN0 | AD7887_PM_MODE4 |
 127                             ((pdata && pdata->use_onchip_ref) ?
 128                             0 : AD7887_REF_DIS);
 129
 130         st->xfer[0].rx_buf = &st->data[0];
 131         st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
 132         st->xfer[0].len = 2;
 133
 134         spi_message_init(&st->msg[AD7887_CH0]);
 135         spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
 136
 137         if (pdata && pdata->en_dual) {
 138                 st->tx_cmd_buf[0] |= AD7887_DUAL | AD7887_REF_DIS;
 139
 140                 st->tx_cmd_buf[2] = AD7887_CH_AIN1 | AD7887_DUAL |
 141                                     AD7887_REF_DIS | AD7887_PM_MODE4;
 142                 st->tx_cmd_buf[4] = AD7887_CH_AIN0 | AD7887_DUAL |
 143                                     AD7887_REF_DIS | AD7887_PM_MODE4;
 144                 st->tx_cmd_buf[6] = AD7887_CH_AIN1 | AD7887_DUAL |
 145                                     AD7887_REF_DIS | AD7887_PM_MODE4;
 146
 147                 st->xfer[1].rx_buf = &st->data[0];
 148                 st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
 149                 st->xfer[1].len = 2;
 150
 151                 st->xfer[2].rx_buf = &st->data[2];
 152                 st->xfer[2].tx_buf = &st->tx_cmd_buf[4];
 153                 st->xfer[2].len = 2;
 154
 155                 spi_message_init(&st->msg[AD7887_CH0_CH1]);
 156                 spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
 157                 spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);
 158
 159                 st->xfer[3].rx_buf = &st->data[0];
 160                 st->xfer[3].tx_buf = &st->tx_cmd_buf[6];
 161                 st->xfer[3].len = 2;
 162
 163                 spi_message_init(&st->msg[AD7887_CH1]);
 164                 spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);
 165
 166                 if (pdata && pdata->vref_mv)
 167                         st->int_vref_mv = pdata->vref_mv;
 168                 else if (voltage_uv)
 169                         st->int_vref_mv = voltage_uv / 1000;
 170                 else
 171                         dev_warn(&spi->dev, "reference voltage unspecified\n");
 172
 173                 indio_dev->channels = st->chip_info->channel;
 174                 indio_dev->num_channels = 3;
 175         } else {
 176                 if (pdata && pdata->vref_mv)
 177                         st->int_vref_mv = pdata->vref_mv;
 178                 else if (pdata && pdata->use_onchip_ref)
 179                         st->int_vref_mv = st->chip_info->int_vref_mv;
 180                 else
 181                         dev_warn(&spi->dev, "reference voltage unspecified\n");
 182
 183                 indio_dev->channels = &st->chip_info->channel[1];
 184                 indio_dev->num_channels = 2;
 185         }
 186
 187         ret = ad7887_register_ring_funcs_and_init(indio_dev);
 188         if (ret)
 189                 goto error_disable_reg;
 190
 191         ret = iio_device_register(indio_dev);
 192         if (ret)
 193                 goto error_disable_reg;
 194         regdone = 1;
 195
 196         ret = iio_ring_buffer_register_ex(indio_dev->ring, 0,
 197                                           indio_dev->channels,
 198                                           indio_dev->num_channels);
 199         if (ret)
 200                 goto error_cleanup_ring;
 201         return 0;
 202
 203 error_cleanup_ring:
 204         ad7887_ring_cleanup(indio_dev);
 205 error_disable_reg:
 206         if (!IS_ERR(st->reg))
 207                 regulator_disable(st->reg);
 208 error_put_reg:
 209         if (!IS_ERR(st->reg))
 210                 regulator_put(st->reg);
 211         if (regdone)
 212                 iio_device_unregister(indio_dev);
 213         else
 214                 iio_free_device(indio_dev);
 215
 216         return ret;
 217 }
 218
 219 static int ad7887_remove(struct spi_device *spi)
 220 {
 221         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 222         struct ad7887_state *st = iio_priv(indio_dev);
 223
 224         iio_ring_buffer_unregister(indio_dev->ring);
 225         ad7887_ring_cleanup(indio_dev);
 226         if (!IS_ERR(st->reg)) {
 227                 regulator_disable(st->reg);
 228                 regulator_put(st->reg);
 229         }
 230         iio_device_unregister(indio_dev);
 231
 232         return 0;
 233 }
 234
 235 static const struct spi_device_id ad7887_id[] = {
 236         {"ad7887", ID_AD7887},
 237         {}
 238 };
 239
 240 static struct spi_driver ad7887_driver = {
 241         .driver = {
 242                 .name   = "ad7887",
 243                 .bus    = &spi_bus_type,
 244                 .owner  = THIS_MODULE,
 245         },
 246         .probe          = ad7887_probe,
 247         .remove         = __devexit_p(ad7887_remove),
 248         .id_table       = ad7887_id,
 249 };
 250
 251 static int __init ad7887_init(void)
 252 {
 253         return spi_register_driver(&ad7887_driver);
 254 }
 255 module_init(ad7887_init);
 256
 257 static void __exit ad7887_exit(void)
 258 {
 259         spi_unregister_driver(&ad7887_driver);
 260 }
 261 module_exit(ad7887_exit);
 262
 263 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 264 MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
 265 MODULE_LICENSE("GPL v2");
 266 MODULE_ALIAS("spi:ad7887");