drivers/staging/iio/adc/ad7780.c

   1 /*
   2  * AD7780/AD7781 SPI ADC driver
   3  *
   4  * Copyright 2011 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2.
   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 #include <linux/sched.h>
  20 #include <linux/gpio.h>
  21
  22 #include "../iio.h"
  23 #include "../sysfs.h"
  24 #include "../ring_generic.h"
  25 #include "adc.h"
  26
  27 #include "ad7780.h"
  28
  29 #define AD7780_RDY      (1 << 7)
  30 #define AD7780_FILTER   (1 << 6)
  31 #define AD7780_ERR      (1 << 5)
  32 #define AD7780_ID1      (1 << 4)
  33 #define AD7780_ID0      (1 << 3)
  34 #define AD7780_GAIN     (1 << 2)
  35 #define AD7780_PAT1     (1 << 1)
  36 #define AD7780_PAT0     (1 << 0)
  37
  38 struct ad7780_chip_info {
  39         struct iio_chan_spec            channel;
  40 };
  41
  42 struct ad7780_state {
  43         struct spi_device               *spi;
  44         const struct ad7780_chip_info   *chip_info;
  45         struct regulator                *reg;
  46         struct ad7780_platform_data     *pdata;
  47         wait_queue_head_t               wq_data_avail;
  48         bool                            done;
  49         u16                             int_vref_mv;
  50         struct spi_transfer             xfer;
  51         struct spi_message              msg;
  52         /*
  53          * DMA (thus cache coherency maintenance) requires the
  54          * transfer buffers to live in their own cache lines.
  55          */
  56         unsigned int                    data ____cacheline_aligned;
  57 };
  58
  59 enum ad7780_supported_device_ids {
  60         ID_AD7780,
  61         ID_AD7781,
  62 };
  63
  64 static int ad7780_read(struct ad7780_state *st, int *val)
  65 {
  66         int ret;
  67
  68         spi_bus_lock(st->spi->master);
  69
  70         enable_irq(st->spi->irq);
  71         st->done = false;
  72         gpio_set_value(st->pdata->gpio_pdrst, 1);
  73
  74         ret = wait_event_interruptible(st->wq_data_avail, st->done);
  75         disable_irq_nosync(st->spi->irq);
  76         if (ret)
  77                 goto out;
  78
  79         ret = spi_sync_locked(st->spi, &st->msg);
  80         *val = be32_to_cpu(st->data);
  81 out:
  82         gpio_set_value(st->pdata->gpio_pdrst, 0);
  83         spi_bus_unlock(st->spi->master);
  84
  85         return ret;
  86 }
  87
  88 static int ad7780_read_raw(struct iio_dev *indio_dev,
  89                            struct iio_chan_spec const *chan,
  90                            int *val,
  91                            int *val2,
  92                            long m)
  93 {
  94         struct ad7780_state *st = iio_priv(indio_dev);
  95         struct iio_chan_spec channel = st->chip_info->channel;
  96         int ret, smpl = 0;
  97         unsigned long scale_uv;
  98
  99         switch (m) {
 100         case 0:
 101                 mutex_lock(&indio_dev->mlock);
 102                 ret = ad7780_read(st, &smpl);
 103                 mutex_unlock(&indio_dev->mlock);
 104
 105                 if (ret < 0)
 106                         return ret;
 107
 108                 if ((smpl & AD7780_ERR) ||
 109                         !((smpl & AD7780_PAT0) && !(smpl & AD7780_PAT1)))
 110                         return -EIO;
 111
 112                 *val = (smpl >> channel.scan_type.shift) &
 113                         ((1 << (channel.scan_type.realbits)) - 1);
 114                 *val -= (1 << (channel.scan_type.realbits - 1));
 115
 116                 if (!(smpl & AD7780_GAIN))
 117                         *val *= 128;
 118
 119                 return IIO_VAL_INT;
 120         case (1 << IIO_CHAN_INFO_SCALE_SHARED):
 121                 scale_uv = (st->int_vref_mv * 100000)
 122                         >> (channel.scan_type.realbits - 1);
 123                 *val =  scale_uv / 100000;
 124                 *val2 = (scale_uv % 100000) * 10;
 125                 return IIO_VAL_INT_PLUS_MICRO;
 126         }
 127         return -EINVAL;
 128 }
 129
 130 static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
 131         [ID_AD7780] = {
 132                 .channel = IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 0, 0,
 133                                     (1 << IIO_CHAN_INFO_SCALE_SHARED),
 134                                     0, 0, IIO_ST('s', 24, 32, 8), 0),
 135         },
 136         [ID_AD7781] = {
 137                 .channel = IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 0, 0,
 138                                     (1 << IIO_CHAN_INFO_SCALE_SHARED),
 139                                     0, 0, IIO_ST('s', 20, 32, 12), 0),
 140         },
 141 };
 142
 143 /**
 144  *  Interrupt handler
 145  */
 146 static irqreturn_t ad7780_interrupt(int irq, void *dev_id)
 147 {
 148         struct ad7780_state *st = dev_id;
 149
 150         st->done = true;
 151         wake_up_interruptible(&st->wq_data_avail);
 152
 153         return IRQ_HANDLED;
 154 };
 155
 156 static int __devinit ad7780_probe(struct spi_device *spi)
 157 {
 158         struct ad7780_platform_data *pdata = spi->dev.platform_data;
 159         struct ad7780_state *st;
 160         struct iio_dev *indio_dev;
 161         int ret, voltage_uv = 0;
 162
 163         if (!pdata) {
 164                 dev_dbg(&spi->dev, "no platform data?\n");
 165                 return -ENODEV;
 166         }
 167
 168         indio_dev = iio_allocate_device(sizeof(*st));
 169         if (indio_dev == NULL)
 170                 return -ENOMEM;
 171
 172         st = iio_priv(indio_dev);
 173
 174         st->reg = regulator_get(&spi->dev, "vcc");
 175         if (!IS_ERR(st->reg)) {
 176                 ret = regulator_enable(st->reg);
 177                 if (ret)
 178                         goto error_put_reg;
 179
 180                 voltage_uv = regulator_get_voltage(st->reg);
 181         }
 182
 183         st->chip_info =
 184                 &ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 185
 186         st->pdata = pdata;
 187
 188         if (pdata && pdata->vref_mv)
 189                 st->int_vref_mv = pdata->vref_mv;
 190         else if (voltage_uv)
 191                 st->int_vref_mv = voltage_uv / 1000;
 192         else
 193                 dev_warn(&spi->dev, "reference voltage unspecified\n");
 194
 195         spi_set_drvdata(spi, indio_dev);
 196         st->spi = spi;
 197
 198         indio_dev->dev.parent = &spi->dev;
 199         indio_dev->name = spi_get_device_id(spi)->name;
 200         indio_dev->driver_module = THIS_MODULE;
 201         indio_dev->modes = INDIO_DIRECT_MODE;
 202         indio_dev->channels = &st->chip_info->channel;
 203         indio_dev->num_channels = 1;
 204         indio_dev->read_raw = &ad7780_read_raw;
 205
 206         init_waitqueue_head(&st->wq_data_avail);
 207
 208         /* Setup default message */
 209
 210         st->xfer.rx_buf = &st->data;
 211         st->xfer.len = st->chip_info->channel.scan_type.storagebits / 8;
 212
 213         spi_message_init(&st->msg);
 214         spi_message_add_tail(&st->xfer, &st->msg);
 215
 216         ret = gpio_request_one(st->pdata->gpio_pdrst, GPIOF_OUT_INIT_LOW,
 217                                "AD7780 /PDRST");
 218         if (ret) {
 219                 dev_err(&spi->dev, "failed to request GPIO PDRST\n");
 220                 goto error_disable_reg;
 221         }
 222
 223         ret = request_irq(spi->irq, ad7780_interrupt,
 224                 IRQF_TRIGGER_FALLING, spi_get_device_id(spi)->name, st);
 225         if (ret)
 226                 goto error_free_gpio;
 227
 228         disable_irq(spi->irq);
 229
 230         ret = iio_device_register(indio_dev);
 231         if (ret)
 232                 goto error_free_irq;
 233
 234         return 0;
 235
 236 error_free_irq:
 237         free_irq(spi->irq, st);
 238 error_free_gpio:
 239         gpio_free(st->pdata->gpio_pdrst);
 240 error_disable_reg:
 241         if (!IS_ERR(st->reg))
 242                 regulator_disable(st->reg);
 243 error_put_reg:
 244         if (!IS_ERR(st->reg))
 245                 regulator_put(st->reg);
 246
 247         iio_free_device(indio_dev);
 248
 249         return ret;
 250 }
 251
 252 static int ad7780_remove(struct spi_device *spi)
 253 {
 254         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 255         struct ad7780_state *st = iio_priv(indio_dev);
 256
 257         free_irq(spi->irq, st);
 258         gpio_free(st->pdata->gpio_pdrst);
 259         if (!IS_ERR(st->reg)) {
 260                 regulator_disable(st->reg);
 261                 regulator_put(st->reg);
 262         }
 263         iio_device_unregister(indio_dev);
 264
 265         return 0;
 266 }
 267
 268 static const struct spi_device_id ad7780_id[] = {
 269         {"ad7780", ID_AD7780},
 270         {"ad7781", ID_AD7781},
 271         {}
 272 };
 273
 274 static struct spi_driver ad7780_driver = {
 275         .driver = {
 276                 .name   = "ad7780",
 277                 .bus    = &spi_bus_type,
 278                 .owner  = THIS_MODULE,
 279         },
 280         .probe          = ad7780_probe,
 281         .remove         = __devexit_p(ad7780_remove),
 282         .id_table       = ad7780_id,
 283 };
 284
 285 static int __init ad7780_init(void)
 286 {
 287         return spi_register_driver(&ad7780_driver);
 288 }
 289 module_init(ad7780_init);
 290
 291 static void __exit ad7780_exit(void)
 292 {
 293         spi_unregister_driver(&ad7780_driver);
 294 }
 295 module_exit(ad7780_exit);
 296
 297 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 298 MODULE_DESCRIPTION("Analog Devices AD7780/1 ADC");
 299 MODULE_LICENSE("GPL v2");