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