drivers/iio/adc/ad7766.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * AD7766/AD7767 SPI ADC driver
   4  *
   5  * Copyright 2016 Analog Devices Inc.
   6  */
   7
   8 #include <linux/clk.h>
   9 #include <linux/delay.h>
  10 #include <linux/device.h>
  11 #include <linux/err.h>
  12 #include <linux/gpio/consumer.h>
  13 #include <linux/module.h>
  14 #include <linux/regulator/consumer.h>
  15 #include <linux/slab.h>
  16 #include <linux/spi/spi.h>
  17
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/buffer.h>
  20 #include <linux/iio/trigger.h>
  21 #include <linux/iio/trigger_consumer.h>
  22 #include <linux/iio/triggered_buffer.h>
  23
  24 struct ad7766_chip_info {
  25         unsigned int decimation_factor;
  26 };
  27
  28 enum {
  29         AD7766_SUPPLY_AVDD = 0,
  30         AD7766_SUPPLY_DVDD = 1,
  31         AD7766_SUPPLY_VREF = 2,
  32         AD7766_NUM_SUPPLIES = 3
  33 };
  34
  35 struct ad7766 {
  36         const struct ad7766_chip_info *chip_info;
  37         struct spi_device *spi;
  38         struct clk *mclk;
  39         struct gpio_desc *pd_gpio;
  40         struct regulator_bulk_data reg[AD7766_NUM_SUPPLIES];
  41
  42         struct iio_trigger *trig;
  43
  44         struct spi_transfer xfer;
  45         struct spi_message msg;
  46
  47         /*
  48          * DMA (thus cache coherency maintenance) may require the
  49          * transfer buffers to live in their own cache lines.
  50          * Make the buffer large enough for one 24 bit sample and one 64 bit
  51          * aligned 64 bit timestamp.
  52          */
  53         unsigned char data[ALIGN(3, sizeof(s64)) + sizeof(s64)] __aligned(IIO_DMA_MINALIGN);
  54 };
  55
  56 /*
  57  * AD7766 and AD7767 variations are interface compatible, the main difference is
  58  * analog performance. Both parts will use the same ID.
  59  */
  60 enum ad7766_device_ids {
  61         ID_AD7766,
  62         ID_AD7766_1,
  63         ID_AD7766_2,
  64 };
  65
  66 static irqreturn_t ad7766_trigger_handler(int irq, void *p)
  67 {
  68         struct iio_poll_func *pf = p;
  69         struct iio_dev *indio_dev = pf->indio_dev;
  70         struct ad7766 *ad7766 = iio_priv(indio_dev);
  71         int ret;
  72
  73         ret = spi_sync(ad7766->spi, &ad7766->msg);
  74         if (ret < 0)
  75                 goto done;
  76
  77         iio_push_to_buffers_with_timestamp(indio_dev, ad7766->data,
  78                 pf->timestamp);
  79 done:
  80         iio_trigger_notify_done(indio_dev->trig);
  81
  82         return IRQ_HANDLED;
  83 }
  84
  85 static int ad7766_preenable(struct iio_dev *indio_dev)
  86 {
  87         struct ad7766 *ad7766 = iio_priv(indio_dev);
  88         int ret;
  89
  90         ret = regulator_bulk_enable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
  91         if (ret < 0) {
  92                 dev_err(&ad7766->spi->dev, "Failed to enable supplies: %d\n",
  93                         ret);
  94                 return ret;
  95         }
  96
  97         ret = clk_prepare_enable(ad7766->mclk);
  98         if (ret < 0) {
  99                 dev_err(&ad7766->spi->dev, "Failed to enable MCLK: %d\n", ret);
 100                 regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
 101                 return ret;
 102         }
 103
 104         gpiod_set_value(ad7766->pd_gpio, 0);
 105
 106         return 0;
 107 }
 108
 109 static int ad7766_postdisable(struct iio_dev *indio_dev)
 110 {
 111         struct ad7766 *ad7766 = iio_priv(indio_dev);
 112
 113         gpiod_set_value(ad7766->pd_gpio, 1);
 114
 115         /*
 116          * The PD pin is synchronous to the clock, so give it some time to
 117          * notice the change before we disable the clock.
 118          */
 119         msleep(20);
 120
 121         clk_disable_unprepare(ad7766->mclk);
 122         regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
 123
 124         return 0;
 125 }
 126
 127 static int ad7766_read_raw(struct iio_dev *indio_dev,
 128         const struct iio_chan_spec *chan, int *val, int *val2, long info)
 129 {
 130         struct ad7766 *ad7766 = iio_priv(indio_dev);
 131         struct regulator *vref = ad7766->reg[AD7766_SUPPLY_VREF].consumer;
 132         int scale_uv;
 133
 134         switch (info) {
 135         case IIO_CHAN_INFO_SCALE:
 136                 scale_uv = regulator_get_voltage(vref);
 137                 if (scale_uv < 0)
 138                         return scale_uv;
 139                 *val = scale_uv / 1000;
 140                 *val2 = chan->scan_type.realbits;
 141                 return IIO_VAL_FRACTIONAL_LOG2;
 142         case IIO_CHAN_INFO_SAMP_FREQ:
 143                 *val = clk_get_rate(ad7766->mclk) /
 144                         ad7766->chip_info->decimation_factor;
 145                 return IIO_VAL_INT;
 146         }
 147         return -EINVAL;
 148 }
 149
 150 static const struct iio_chan_spec ad7766_channels[] = {
 151         {
 152                 .type = IIO_VOLTAGE,
 153                 .indexed = 1,
 154                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 155                 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 156                 .scan_type = {
 157                         .sign = 's',
 158                         .realbits = 24,
 159                         .storagebits = 32,
 160                         .endianness = IIO_BE,
 161                 },
 162         },
 163         IIO_CHAN_SOFT_TIMESTAMP(1),
 164 };
 165
 166 static const struct ad7766_chip_info ad7766_chip_info[] = {
 167         [ID_AD7766] = {
 168                 .decimation_factor = 8,
 169         },
 170         [ID_AD7766_1] = {
 171                 .decimation_factor = 16,
 172         },
 173         [ID_AD7766_2] = {
 174                 .decimation_factor = 32,
 175         },
 176 };
 177
 178 static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = {
 179         .preenable = &ad7766_preenable,
 180         .postdisable = &ad7766_postdisable,
 181 };
 182
 183 static const struct iio_info ad7766_info = {
 184         .read_raw = &ad7766_read_raw,
 185 };
 186
 187 static irqreturn_t ad7766_irq(int irq, void *private)
 188 {
 189         iio_trigger_poll(private);
 190         return IRQ_HANDLED;
 191 }
 192
 193 static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable)
 194 {
 195         struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig);
 196
 197         if (enable)
 198                 enable_irq(ad7766->spi->irq);
 199         else
 200                 disable_irq(ad7766->spi->irq);
 201
 202         return 0;
 203 }
 204
 205 static const struct iio_trigger_ops ad7766_trigger_ops = {
 206         .set_trigger_state = ad7766_set_trigger_state,
 207         .validate_device = iio_trigger_validate_own_device,
 208 };
 209
 210 static int ad7766_probe(struct spi_device *spi)
 211 {
 212         const struct spi_device_id *id = spi_get_device_id(spi);
 213         struct iio_dev *indio_dev;
 214         struct ad7766 *ad7766;
 215         int ret;
 216
 217         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ad7766));
 218         if (!indio_dev)
 219                 return -ENOMEM;
 220
 221         ad7766 = iio_priv(indio_dev);
 222         ad7766->chip_info = &ad7766_chip_info[id->driver_data];
 223
 224         ad7766->mclk = devm_clk_get(&spi->dev, "mclk");
 225         if (IS_ERR(ad7766->mclk))
 226                 return PTR_ERR(ad7766->mclk);
 227
 228         ad7766->reg[AD7766_SUPPLY_AVDD].supply = "avdd";
 229         ad7766->reg[AD7766_SUPPLY_DVDD].supply = "dvdd";
 230         ad7766->reg[AD7766_SUPPLY_VREF].supply = "vref";
 231
 232         ret = devm_regulator_bulk_get(&spi->dev, ARRAY_SIZE(ad7766->reg),
 233                 ad7766->reg);
 234         if (ret)
 235                 return ret;
 236
 237         ad7766->pd_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown",
 238                 GPIOD_OUT_HIGH);
 239         if (IS_ERR(ad7766->pd_gpio))
 240                 return PTR_ERR(ad7766->pd_gpio);
 241
 242         indio_dev->name = spi_get_device_id(spi)->name;
 243         indio_dev->modes = INDIO_DIRECT_MODE;
 244         indio_dev->channels = ad7766_channels;
 245         indio_dev->num_channels = ARRAY_SIZE(ad7766_channels);
 246         indio_dev->info = &ad7766_info;
 247
 248         if (spi->irq > 0) {
 249                 ad7766->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
 250                                                       indio_dev->name,
 251                                                       iio_device_id(indio_dev));
 252                 if (!ad7766->trig)
 253                         return -ENOMEM;
 254
 255                 ad7766->trig->ops = &ad7766_trigger_ops;
 256                 iio_trigger_set_drvdata(ad7766->trig, ad7766);
 257
 258                 /*
 259                  * The device generates interrupts as long as it is powered up.
 260                  * Some platforms might not allow the option to power it down so
 261                  * don't enable the interrupt to avoid extra load on the system
 262                  */
 263                 ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq,
 264                                        IRQF_TRIGGER_FALLING | IRQF_NO_AUTOEN,
 265                                        dev_name(&spi->dev),
 266                                        ad7766->trig);
 267                 if (ret < 0)
 268                         return ret;
 269
 270                 ret = devm_iio_trigger_register(&spi->dev, ad7766->trig);
 271                 if (ret)
 272                         return ret;
 273         }
 274
 275         ad7766->spi = spi;
 276
 277         /* First byte always 0 */
 278         ad7766->xfer.rx_buf = &ad7766->data[1];
 279         ad7766->xfer.len = 3;
 280
 281         spi_message_init(&ad7766->msg);
 282         spi_message_add_tail(&ad7766->xfer, &ad7766->msg);
 283
 284         ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
 285                 &iio_pollfunc_store_time, &ad7766_trigger_handler,
 286                 &ad7766_buffer_setup_ops);
 287         if (ret)
 288                 return ret;
 289
 290         return devm_iio_device_register(&spi->dev, indio_dev);
 291 }
 292
 293 static const struct spi_device_id ad7766_id[] = {
 294         { "ad7766", ID_AD7766 },
 295         { "ad7766-1", ID_AD7766_1 },
 296         { "ad7766-2", ID_AD7766_2 },
 297         { "ad7767", ID_AD7766 },
 298         { "ad7767-1", ID_AD7766_1 },
 299         { "ad7767-2", ID_AD7766_2 },
 300         { }
 301 };
 302 MODULE_DEVICE_TABLE(spi, ad7766_id);
 303
 304 static struct spi_driver ad7766_driver = {
 305         .driver = {
 306                 .name   = "ad7766",
 307         },
 308         .probe          = ad7766_probe,
 309         .id_table       = ad7766_id,
 310 };
 311 module_spi_driver(ad7766_driver);
 312
 313 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 314 MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support");
 315 MODULE_LICENSE("GPL v2");