drivers/staging/iio/adc/ad7887_core.c

   1 /*
   2  * AD7887 SPI ADC driver
   3  *
   4  * Copyright 2010 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/workqueue.h>
  11 #include <linux/device.h>
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/sysfs.h>
  15 #include <linux/list.h>
  16 #include <linux/spi/spi.h>
  17 #include <linux/regulator/consumer.h>
  18 #include <linux/err.h>
  19
  20 #include "../iio.h"
  21 #include "../sysfs.h"
  22 #include "../ring_generic.h"
  23 #include "adc.h"
  24
  25 #include "ad7887.h"
  26
  27 static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
  28 {
  29         int ret = spi_sync(st->spi, &st->msg[ch]);
  30         if (ret)
  31                 return ret;
  32
  33         return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
  34 }
  35
  36 static ssize_t ad7887_scan(struct device *dev,
  37                             struct device_attribute *attr,
  38                             char *buf)
  39 {
  40         struct iio_dev *dev_info = dev_get_drvdata(dev);
  41         struct ad7887_state *st = dev_info->dev_data;
  42         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
  43         int ret;
  44
  45         mutex_lock(&dev_info->mlock);
  46         if (iio_ring_enabled(dev_info))
  47                 ret = ad7887_scan_from_ring(st, 1 << this_attr->address);
  48         else
  49                 ret = ad7887_scan_direct(st, this_attr->address);
  50         mutex_unlock(&dev_info->mlock);
  51
  52         if (ret < 0)
  53                 return ret;
  54
  55         return sprintf(buf, "%d\n", (ret >> st->chip_info->left_shift) &
  56                        RES_MASK(st->chip_info->bits));
  57 }
  58 static IIO_DEV_ATTR_IN_RAW(0, ad7887_scan, 0);
  59 static IIO_DEV_ATTR_IN_RAW(1, ad7887_scan, 1);
  60
  61 static ssize_t ad7887_show_scale(struct device *dev,
  62                                 struct device_attribute *attr,
  63                                 char *buf)
  64 {
  65         /* Driver currently only support internal vref */
  66         struct iio_dev *dev_info = dev_get_drvdata(dev);
  67         struct ad7887_state *st = iio_dev_get_devdata(dev_info);
  68         /* Corresponds to Vref / 2^(bits) */
  69         unsigned int scale_uv = (st->int_vref_mv * 1000) >> st->chip_info->bits;
  70
  71         return sprintf(buf, "%d.%d\n", scale_uv / 1000, scale_uv % 1000);
  72 }
  73 static IIO_DEVICE_ATTR(in_scale, S_IRUGO, ad7887_show_scale, NULL, 0);
  74
  75 static ssize_t ad7887_show_name(struct device *dev,
  76                                  struct device_attribute *attr,
  77                                  char *buf)
  78 {
  79         struct iio_dev *dev_info = dev_get_drvdata(dev);
  80         struct ad7887_state *st = iio_dev_get_devdata(dev_info);
  81
  82         return sprintf(buf, "%s\n", spi_get_device_id(st->spi)->name);
  83 }
  84 static IIO_DEVICE_ATTR(name, S_IRUGO, ad7887_show_name, NULL, 0);
  85
  86 static struct attribute *ad7887_attributes[] = {
  87         &iio_dev_attr_in0_raw.dev_attr.attr,
  88         &iio_dev_attr_in1_raw.dev_attr.attr,
  89         &iio_dev_attr_in_scale.dev_attr.attr,
  90         &iio_dev_attr_name.dev_attr.attr,
  91         NULL,
  92 };
  93
  94 static mode_t ad7887_attr_is_visible(struct kobject *kobj,
  95                                      struct attribute *attr, int n)
  96 {
  97         struct device *dev = container_of(kobj, struct device, kobj);
  98         struct iio_dev *dev_info = dev_get_drvdata(dev);
  99         struct ad7887_state *st = iio_dev_get_devdata(dev_info);
 100
 101         mode_t mode = attr->mode;
 102
 103         if ((attr == &iio_dev_attr_in1_raw.dev_attr.attr) && !st->en_dual)
 104                         mode = 0;
 105
 106         return mode;
 107 }
 108
 109 static const struct attribute_group ad7887_attribute_group = {
 110         .attrs = ad7887_attributes,
 111         .is_visible = ad7887_attr_is_visible,
 112 };
 113
 114 static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
 115         /*
 116          * More devices added in future
 117          */
 118         [ID_AD7887] = {
 119                 .bits = 12,
 120                 .storagebits = 16,
 121                 .left_shift = 0,
 122                 .sign = IIO_SCAN_EL_TYPE_UNSIGNED,
 123                 .int_vref_mv = 2500,
 124         },
 125 };
 126
 127 static int __devinit ad7887_probe(struct spi_device *spi)
 128 {
 129         struct ad7887_platform_data *pdata = spi->dev.platform_data;
 130         struct ad7887_state *st;
 131         int ret, voltage_uv = 0;
 132
 133         st = kzalloc(sizeof(*st), GFP_KERNEL);
 134         if (st == NULL) {
 135                 ret = -ENOMEM;
 136                 goto error_ret;
 137         }
 138
 139         st->reg = regulator_get(&spi->dev, "vcc");
 140         if (!IS_ERR(st->reg)) {
 141                 ret = regulator_enable(st->reg);
 142                 if (ret)
 143                         goto error_put_reg;
 144
 145                 voltage_uv = regulator_get_voltage(st->reg);
 146         }
 147
 148         st->chip_info =
 149                 &ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 150
 151         spi_set_drvdata(spi, st);
 152
 153         atomic_set(&st->protect_ring, 0);
 154         st->spi = spi;
 155
 156         st->indio_dev = iio_allocate_device();
 157         if (st->indio_dev == NULL) {
 158                 ret = -ENOMEM;
 159                 goto error_disable_reg;
 160         }
 161
 162         /* Estabilish that the iio_dev is a child of the spi device */
 163         st->indio_dev->dev.parent = &spi->dev;
 164         st->indio_dev->attrs = &ad7887_attribute_group;
 165         st->indio_dev->dev_data = (void *)(st);
 166         st->indio_dev->driver_module = THIS_MODULE;
 167         st->indio_dev->modes = INDIO_DIRECT_MODE;
 168
 169         /* Setup default message */
 170
 171         st->tx_cmd_buf[0] = AD7887_CH_AIN0 | AD7887_PM_MODE4 |
 172                             ((pdata && pdata->use_onchip_ref) ?
 173                             0 : AD7887_REF_DIS);
 174
 175         st->xfer[0].rx_buf = &st->data[0];
 176         st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
 177         st->xfer[0].len = 2;
 178
 179         spi_message_init(&st->msg[AD7887_CH0]);
 180         spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
 181
 182         if (pdata && pdata->en_dual) {
 183                 st->tx_cmd_buf[0] |= AD7887_DUAL | AD7887_REF_DIS;
 184
 185                 st->tx_cmd_buf[2] = AD7887_CH_AIN1 | AD7887_DUAL |
 186                                     AD7887_REF_DIS | AD7887_PM_MODE4;
 187                 st->tx_cmd_buf[4] = AD7887_CH_AIN0 | AD7887_DUAL |
 188                                     AD7887_REF_DIS | AD7887_PM_MODE4;
 189                 st->tx_cmd_buf[6] = AD7887_CH_AIN1 | AD7887_DUAL |
 190                                     AD7887_REF_DIS | AD7887_PM_MODE4;
 191
 192                 st->xfer[1].rx_buf = &st->data[0];
 193                 st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
 194                 st->xfer[1].len = 2;
 195
 196                 st->xfer[2].rx_buf = &st->data[2];
 197                 st->xfer[2].tx_buf = &st->tx_cmd_buf[4];
 198                 st->xfer[2].len = 2;
 199
 200                 spi_message_init(&st->msg[AD7887_CH0_CH1]);
 201                 spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
 202                 spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);
 203
 204                 st->xfer[3].rx_buf = &st->data[0];
 205                 st->xfer[3].tx_buf = &st->tx_cmd_buf[6];
 206                 st->xfer[3].len = 2;
 207
 208                 spi_message_init(&st->msg[AD7887_CH1]);
 209                 spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);
 210
 211                 st->en_dual = true;
 212
 213                 if (pdata && pdata->vref_mv)
 214                         st->int_vref_mv = pdata->vref_mv;
 215                 else if (voltage_uv)
 216                         st->int_vref_mv = voltage_uv / 1000;
 217                 else
 218                         dev_warn(&spi->dev, "reference voltage unspecified\n");
 219
 220         } else {
 221                 if (pdata && pdata->vref_mv)
 222                         st->int_vref_mv = pdata->vref_mv;
 223                 else if (pdata && pdata->use_onchip_ref)
 224                         st->int_vref_mv = st->chip_info->int_vref_mv;
 225                 else
 226                         dev_warn(&spi->dev, "reference voltage unspecified\n");
 227         }
 228
 229
 230         ret = ad7887_register_ring_funcs_and_init(st->indio_dev);
 231         if (ret)
 232                 goto error_free_device;
 233
 234         ret = iio_device_register(st->indio_dev);
 235         if (ret)
 236                 goto error_free_device;
 237
 238         ret = iio_ring_buffer_register(st->indio_dev->ring, 0);
 239         if (ret)
 240                 goto error_cleanup_ring;
 241         return 0;
 242
 243 error_cleanup_ring:
 244         ad7887_ring_cleanup(st->indio_dev);
 245         iio_device_unregister(st->indio_dev);
 246 error_free_device:
 247         iio_free_device(st->indio_dev);
 248 error_disable_reg:
 249         if (!IS_ERR(st->reg))
 250                 regulator_disable(st->reg);
 251 error_put_reg:
 252         if (!IS_ERR(st->reg))
 253                 regulator_put(st->reg);
 254         kfree(st);
 255 error_ret:
 256         return ret;
 257 }
 258
 259 static int ad7887_remove(struct spi_device *spi)
 260 {
 261         struct ad7887_state *st = spi_get_drvdata(spi);
 262         struct iio_dev *indio_dev = st->indio_dev;
 263         iio_ring_buffer_unregister(indio_dev->ring);
 264         ad7887_ring_cleanup(indio_dev);
 265         iio_device_unregister(indio_dev);
 266         if (!IS_ERR(st->reg)) {
 267                 regulator_disable(st->reg);
 268                 regulator_put(st->reg);
 269         }
 270         kfree(st);
 271         return 0;
 272 }
 273
 274 static const struct spi_device_id ad7887_id[] = {
 275         {"ad7887", ID_AD7887},
 276         {}
 277 };
 278
 279 static struct spi_driver ad7887_driver = {
 280         .driver = {
 281                 .name   = "ad7887",
 282                 .bus    = &spi_bus_type,
 283                 .owner  = THIS_MODULE,
 284         },
 285         .probe          = ad7887_probe,
 286         .remove         = __devexit_p(ad7887_remove),
 287         .id_table       = ad7887_id,
 288 };
 289
 290 static int __init ad7887_init(void)
 291 {
 292         return spi_register_driver(&ad7887_driver);
 293 }
 294 module_init(ad7887_init);
 295
 296 static void __exit ad7887_exit(void)
 297 {
 298         spi_unregister_driver(&ad7887_driver);
 299 }
 300 module_exit(ad7887_exit);
 301
 302 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 303 MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
 304 MODULE_LICENSE("GPL v2");
 305 MODULE_ALIAS("spi:ad7887");