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/device.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/sysfs.h>
  14 #include <linux/spi/spi.h>
  15 #include <linux/regulator/consumer.h>
  16 #include <linux/err.h>
  17 #include <linux/sched.h>
  18 #include <linux/gpio.h>
  19
  20 #include "../iio.h"
  21 #include "../sysfs.h"
  22 #include "../ring_generic.h"
  23 #include "adc.h"
  24
  25 #include "ad7780.h"
  26
  27 #define AD7780_RDY      (1 << 7)
  28 #define AD7780_FILTER   (1 << 6)
  29 #define AD7780_ERR      (1 << 5)
  30 #define AD7780_ID1      (1 << 4)
  31 #define AD7780_ID0      (1 << 3)
  32 #define AD7780_GAIN     (1 << 2)
  33 #define AD7780_PAT1     (1 << 1)
  34 #define AD7780_PAT0     (1 << 0)
  35
  36 struct ad7780_chip_info {
  37         struct iio_chan_spec            channel;
  38 };
  39
  40 struct ad7780_state {
  41         struct spi_device               *spi;
  42         const struct ad7780_chip_info   *chip_info;
  43         struct regulator                *reg;
  44         struct ad7780_platform_data     *pdata;
  45         wait_queue_head_t               wq_data_avail;
  46         bool                            done;
  47         u16                             int_vref_mv;
  48         struct spi_transfer             xfer;
  49         struct spi_message              msg;
  50         /*
  51          * DMA (thus cache coherency maintenance) requires the
  52          * transfer buffers to live in their own cache lines.
  53          */
  54         unsigned int                    data ____cacheline_aligned;
  55 };
  56
  57 enum ad7780_supported_device_ids {
  58         ID_AD7780,
  59         ID_AD7781,
  60 };
  61
  62 static int ad7780_read(struct ad7780_state *st, int *val)
  63 {
  64         int ret;
  65
  66         spi_bus_lock(st->spi->master);
  67
  68         enable_irq(st->spi->irq);
  69         st->done = false;
  70         gpio_set_value(st->pdata->gpio_pdrst, 1);
  71
  72         ret = wait_event_interruptible(st->wq_data_avail, st->done);
  73         disable_irq_nosync(st->spi->irq);
  74         if (ret)
  75                 goto out;
  76
  77         ret = spi_sync_locked(st->spi, &st->msg);
  78         *val = be32_to_cpu(st->data);
  79 out:
  80         gpio_set_value(st->pdata->gpio_pdrst, 0);
  81         spi_bus_unlock(st->spi->master);
  82
  83         return ret;
  84 }
  85
  86 static int ad7780_read_raw(struct iio_dev *indio_dev,
  87                            struct iio_chan_spec const *chan,
  88                            int *val,
  89                            int *val2,
  90                            long m)
  91 {
  92         struct ad7780_state *st = iio_priv(indio_dev);
  93         struct iio_chan_spec channel = st->chip_info->channel;
  94         int ret, smpl = 0;
  95         unsigned long scale_uv;
  96
  97         switch (m) {
  98         case 0:
  99                 mutex_lock(&indio_dev->mlock);
 100                 ret = ad7780_read(st, &smpl);
 101                 mutex_unlock(&indio_dev->mlock);
 102
 103                 if (ret < 0)
 104                         return ret;
 105
 106                 if ((smpl & AD7780_ERR) ||
 107                         !((smpl & AD7780_PAT0) && !(smpl & AD7780_PAT1)))
 108                         return -EIO;
 109
 110                 *val = (smpl >> channel.scan_type.shift) &
 111                         ((1 << (channel.scan_type.realbits)) - 1);
 112                 *val -= (1 << (channel.scan_type.realbits - 1));
 113
 114                 if (!(smpl & AD7780_GAIN))
 115                         *val *= 128;
 116
 117                 return IIO_VAL_INT;
 118         case (1 << IIO_CHAN_INFO_SCALE_SHARED):
 119                 scale_uv = (st->int_vref_mv * 100000)
 120                         >> (channel.scan_type.realbits - 1);
 121                 *val =  scale_uv / 100000;
 122                 *val2 = (scale_uv % 100000) * 10;
 123                 return IIO_VAL_INT_PLUS_MICRO;
 124         }
 125         return -EINVAL;
 126 }
 127
 128 static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
 129         [ID_AD7780] = {
 130                 .channel = IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 0, 0,
 131                                     (1 << IIO_CHAN_INFO_SCALE_SHARED),
 132                                     0, 0, IIO_ST('s', 24, 32, 8), 0),
 133         },
 134         [ID_AD7781] = {
 135                 .channel = IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 0, 0,
 136                                     (1 << IIO_CHAN_INFO_SCALE_SHARED),
 137                                     0, 0, IIO_ST('s', 20, 32, 12), 0),
 138         },
 139 };
 140
 141 /**
 142  *  Interrupt handler
 143  */
 144 static irqreturn_t ad7780_interrupt(int irq, void *dev_id)
 145 {
 146         struct ad7780_state *st = dev_id;
 147
 148         st->done = true;
 149         wake_up_interruptible(&st->wq_data_avail);
 150
 151         return IRQ_HANDLED;
 152 };
 153
 154 static const struct iio_info ad7780_info = {
 155         .read_raw = &ad7780_read_raw,
 156         .driver_module = THIS_MODULE,
 157 };
 158
 159 static int __devinit ad7780_probe(struct spi_device *spi)
 160 {
 161         struct ad7780_platform_data *pdata = spi->dev.platform_data;
 162         struct ad7780_state *st;
 163         struct iio_dev *indio_dev;
 164         int ret, voltage_uv = 0;
 165
 166         if (!pdata) {
 167                 dev_dbg(&spi->dev, "no platform data?\n");
 168                 return -ENODEV;
 169         }
 170
 171         indio_dev = iio_allocate_device(sizeof(*st));
 172         if (indio_dev == NULL)
 173                 return -ENOMEM;
 174
 175         st = iio_priv(indio_dev);
 176
 177         st->reg = regulator_get(&spi->dev, "vcc");
 178         if (!IS_ERR(st->reg)) {
 179                 ret = regulator_enable(st->reg);
 180                 if (ret)
 181                         goto error_put_reg;
 182
 183                 voltage_uv = regulator_get_voltage(st->reg);
 184         }
 185
 186         st->chip_info =
 187                 &ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 188
 189         st->pdata = pdata;
 190
 191         if (pdata && pdata->vref_mv)
 192                 st->int_vref_mv = pdata->vref_mv;
 193         else if (voltage_uv)
 194                 st->int_vref_mv = voltage_uv / 1000;
 195         else
 196                 dev_warn(&spi->dev, "reference voltage unspecified\n");
 197
 198         spi_set_drvdata(spi, indio_dev);
 199         st->spi = spi;
 200
 201         indio_dev->dev.parent = &spi->dev;
 202         indio_dev->name = spi_get_device_id(spi)->name;
 203         indio_dev->modes = INDIO_DIRECT_MODE;
 204         indio_dev->channels = &st->chip_info->channel;
 205         indio_dev->num_channels = 1;
 206         indio_dev->info = &ad7780_info;
 207
 208         init_waitqueue_head(&st->wq_data_avail);
 209
 210         /* Setup default message */
 211
 212         st->xfer.rx_buf = &st->data;
 213         st->xfer.len = st->chip_info->channel.scan_type.storagebits / 8;
 214
 215         spi_message_init(&st->msg);
 216         spi_message_add_tail(&st->xfer, &st->msg);
 217
 218         ret = gpio_request_one(st->pdata->gpio_pdrst, GPIOF_OUT_INIT_LOW,
 219                                "AD7780 /PDRST");
 220         if (ret) {
 221                 dev_err(&spi->dev, "failed to request GPIO PDRST\n");
 222                 goto error_disable_reg;
 223         }
 224
 225         ret = request_irq(spi->irq, ad7780_interrupt,
 226                 IRQF_TRIGGER_FALLING, spi_get_device_id(spi)->name, st);
 227         if (ret)
 228                 goto error_free_gpio;
 229
 230         disable_irq(spi->irq);
 231
 232         ret = iio_device_register(indio_dev);
 233         if (ret)
 234                 goto error_free_irq;
 235
 236         return 0;
 237
 238 error_free_irq:
 239         free_irq(spi->irq, st);
 240 error_free_gpio:
 241         gpio_free(st->pdata->gpio_pdrst);
 242 error_disable_reg:
 243         if (!IS_ERR(st->reg))
 244                 regulator_disable(st->reg);
 245 error_put_reg:
 246         if (!IS_ERR(st->reg))
 247                 regulator_put(st->reg);
 248
 249         iio_free_device(indio_dev);
 250
 251         return ret;
 252 }
 253
 254 static int ad7780_remove(struct spi_device *spi)
 255 {
 256         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 257         struct ad7780_state *st = iio_priv(indio_dev);
 258
 259         free_irq(spi->irq, st);
 260         gpio_free(st->pdata->gpio_pdrst);
 261         if (!IS_ERR(st->reg)) {
 262                 regulator_disable(st->reg);
 263                 regulator_put(st->reg);
 264         }
 265         iio_device_unregister(indio_dev);
 266
 267         return 0;
 268 }
 269
 270 static const struct spi_device_id ad7780_id[] = {
 271         {"ad7780", ID_AD7780},
 272         {"ad7781", ID_AD7781},
 273         {}
 274 };
 275
 276 static struct spi_driver ad7780_driver = {
 277         .driver = {
 278                 .name   = "ad7780",
 279                 .bus    = &spi_bus_type,
 280                 .owner  = THIS_MODULE,
 281         },
 282         .probe          = ad7780_probe,
 283         .remove         = __devexit_p(ad7780_remove),
 284         .id_table       = ad7780_id,
 285 };
 286
 287 static int __init ad7780_init(void)
 288 {
 289         return spi_register_driver(&ad7780_driver);
 290 }
 291 module_init(ad7780_init);
 292
 293 static void __exit ad7780_exit(void)
 294 {
 295         spi_unregister_driver(&ad7780_driver);
 296 }
 297 module_exit(ad7780_exit);
 298
 299 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 300 MODULE_DESCRIPTION("Analog Devices AD7780/1 ADC");
 301 MODULE_LICENSE("GPL v2");