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