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) requires 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)]
  54                         ____cacheline_aligned;
  55 };
  56
  57 /*
  58  * AD7766 and AD7767 variations are interface compatible, the main difference is
  59  * analog performance. Both parts will use the same ID.
  60  */
  61 enum ad7766_device_ids {
  62         ID_AD7766,
  63         ID_AD7766_1,
  64         ID_AD7766_2,
  65 };
  66
  67 static irqreturn_t ad7766_trigger_handler(int irq, void *p)
  68 {
  69         struct iio_poll_func *pf = p;
  70         struct iio_dev *indio_dev = pf->indio_dev;
  71         struct ad7766 *ad7766 = iio_priv(indio_dev);
  72         int ret;
  73
  74         ret = spi_sync(ad7766->spi, &ad7766->msg);
  75         if (ret < 0)
  76                 goto done;
  77
  78         iio_push_to_buffers_with_timestamp(indio_dev, ad7766->data,
  79                 pf->timestamp);
  80 done:
  81         iio_trigger_notify_done(indio_dev->trig);
  82
  83         return IRQ_HANDLED;
  84 }
  85
  86 static int ad7766_preenable(struct iio_dev *indio_dev)
  87 {
  88         struct ad7766 *ad7766 = iio_priv(indio_dev);
  89         int ret;
  90
  91         ret = regulator_bulk_enable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
  92         if (ret < 0) {
  93                 dev_err(&ad7766->spi->dev, "Failed to enable supplies: %d\n",
  94                         ret);
  95                 return ret;
  96         }
  97
  98         ret = clk_prepare_enable(ad7766->mclk);
  99         if (ret < 0) {
 100                 dev_err(&ad7766->spi->dev, "Failed to enable MCLK: %d\n", ret);
 101                 regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
 102                 return ret;
 103         }
 104
 105         gpiod_set_value(ad7766->pd_gpio, 0);
 106
 107         return 0;
 108 }
 109
 110 static int ad7766_postdisable(struct iio_dev *indio_dev)
 111 {
 112         struct ad7766 *ad7766 = iio_priv(indio_dev);
 113
 114         gpiod_set_value(ad7766->pd_gpio, 1);
 115
 116         /*
 117          * The PD pin is synchronous to the clock, so give it some time to
 118          * notice the change before we disable the clock.
 119          */
 120         msleep(20);
 121
 122         clk_disable_unprepare(ad7766->mclk);
 123         regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
 124
 125         return 0;
 126 }
 127
 128 static int ad7766_read_raw(struct iio_dev *indio_dev,
 129         const struct iio_chan_spec *chan, int *val, int *val2, long info)
 130 {
 131         struct ad7766 *ad7766 = iio_priv(indio_dev);
 132         struct regulator *vref = ad7766->reg[AD7766_SUPPLY_VREF].consumer;
 133         int scale_uv;
 134
 135         switch (info) {
 136         case IIO_CHAN_INFO_SCALE:
 137                 scale_uv = regulator_get_voltage(vref);
 138                 if (scale_uv < 0)
 139                         return scale_uv;
 140                 *val = scale_uv / 1000;
 141                 *val2 = chan->scan_type.realbits;
 142                 return IIO_VAL_FRACTIONAL_LOG2;
 143         case IIO_CHAN_INFO_SAMP_FREQ:
 144                 *val = clk_get_rate(ad7766->mclk) /
 145                         ad7766->chip_info->decimation_factor;
 146                 return IIO_VAL_INT;
 147         }
 148         return -EINVAL;
 149 }
 150
 151 static const struct iio_chan_spec ad7766_channels[] = {
 152         {
 153                 .type = IIO_VOLTAGE,
 154                 .indexed = 1,
 155                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 156                 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 157                 .scan_type = {
 158                         .sign = 's',
 159                         .realbits = 24,
 160                         .storagebits = 32,
 161                         .endianness = IIO_BE,
 162                 },
 163         },
 164         IIO_CHAN_SOFT_TIMESTAMP(1),
 165 };
 166
 167 static const struct ad7766_chip_info ad7766_chip_info[] = {
 168         [ID_AD7766] = {
 169                 .decimation_factor = 8,
 170         },
 171         [ID_AD7766_1] = {
 172                 .decimation_factor = 16,
 173         },
 174         [ID_AD7766_2] = {
 175                 .decimation_factor = 32,
 176         },
 177 };
 178
 179 static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = {
 180         .preenable = &ad7766_preenable,
 181         .postdisable = &ad7766_postdisable,
 182 };
 183
 184 static const struct iio_info ad7766_info = {
 185         .read_raw = &ad7766_read_raw,
 186 };
 187
 188 static irqreturn_t ad7766_irq(int irq, void *private)
 189 {
 190         iio_trigger_poll(private);
 191         return IRQ_HANDLED;
 192 }
 193
 194 static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable)
 195 {
 196         struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig);
 197
 198         if (enable)
 199                 enable_irq(ad7766->spi->irq);
 200         else
 201                 disable_irq(ad7766->spi->irq);
 202
 203         return 0;
 204 }
 205
 206 static const struct iio_trigger_ops ad7766_trigger_ops = {
 207         .set_trigger_state = ad7766_set_trigger_state,
 208         .validate_device = iio_trigger_validate_own_device,
 209 };
 210
 211 static int ad7766_probe(struct spi_device *spi)
 212 {
 213         const struct spi_device_id *id = spi_get_device_id(spi);
 214         struct iio_dev *indio_dev;
 215         struct ad7766 *ad7766;
 216         int ret;
 217
 218         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ad7766));
 219         if (!indio_dev)
 220                 return -ENOMEM;
 221
 222         ad7766 = iio_priv(indio_dev);
 223         ad7766->chip_info = &ad7766_chip_info[id->driver_data];
 224
 225         ad7766->mclk = devm_clk_get(&spi->dev, "mclk");
 226         if (IS_ERR(ad7766->mclk))
 227                 return PTR_ERR(ad7766->mclk);
 228
 229         ad7766->reg[AD7766_SUPPLY_AVDD].supply = "avdd";
 230         ad7766->reg[AD7766_SUPPLY_DVDD].supply = "dvdd";
 231         ad7766->reg[AD7766_SUPPLY_VREF].supply = "vref";
 232
 233         ret = devm_regulator_bulk_get(&spi->dev, ARRAY_SIZE(ad7766->reg),
 234                 ad7766->reg);
 235         if (ret)
 236                 return ret;
 237
 238         ad7766->pd_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown",
 239                 GPIOD_OUT_HIGH);
 240         if (IS_ERR(ad7766->pd_gpio))
 241                 return PTR_ERR(ad7766->pd_gpio);
 242
 243         indio_dev->name = spi_get_device_id(spi)->name;
 244         indio_dev->modes = INDIO_DIRECT_MODE;
 245         indio_dev->channels = ad7766_channels;
 246         indio_dev->num_channels = ARRAY_SIZE(ad7766_channels);
 247         indio_dev->info = &ad7766_info;
 248
 249         if (spi->irq > 0) {
 250                 ad7766->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
 251                         indio_dev->name, indio_dev->id);
 252                 if (!ad7766->trig)
 253                         return -ENOMEM;
 254
 255                 ad7766->trig->ops = &ad7766_trigger_ops;
 256                 ad7766->trig->dev.parent = &spi->dev;
 257                 iio_trigger_set_drvdata(ad7766->trig, ad7766);
 258
 259                 ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq,
 260                         IRQF_TRIGGER_FALLING, dev_name(&spi->dev),
 261                         ad7766->trig);
 262                 if (ret < 0)
 263                         return ret;
 264
 265                 /*
 266                  * The device generates interrupts as long as it is powered up.
 267                  * Some platforms might not allow the option to power it down so
 268                  * disable the interrupt to avoid extra load on the system
 269                  */
 270                 disable_irq(spi->irq);
 271
 272                 ret = devm_iio_trigger_register(&spi->dev, ad7766->trig);
 273                 if (ret)
 274                         return ret;
 275         }
 276
 277         spi_set_drvdata(spi, indio_dev);
 278
 279         ad7766->spi = spi;
 280
 281         /* First byte always 0 */
 282         ad7766->xfer.rx_buf = &ad7766->data[1];
 283         ad7766->xfer.len = 3;
 284
 285         spi_message_init(&ad7766->msg);
 286         spi_message_add_tail(&ad7766->xfer, &ad7766->msg);
 287
 288         ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
 289                 &iio_pollfunc_store_time, &ad7766_trigger_handler,
 290                 &ad7766_buffer_setup_ops);
 291         if (ret)
 292                 return ret;
 293
 294         ret = devm_iio_device_register(&spi->dev, indio_dev);
 295         if (ret)
 296                 return ret;
 297         return 0;
 298 }
 299
 300 static const struct spi_device_id ad7766_id[] = {
 301         {"ad7766", ID_AD7766},
 302         {"ad7766-1", ID_AD7766_1},
 303         {"ad7766-2", ID_AD7766_2},
 304         {"ad7767", ID_AD7766},
 305         {"ad7767-1", ID_AD7766_1},
 306         {"ad7767-2", ID_AD7766_2},
 307         {}
 308 };
 309 MODULE_DEVICE_TABLE(spi, ad7766_id);
 310
 311 static struct spi_driver ad7766_driver = {
 312         .driver = {
 313                 .name   = "ad7766",
 314         },
 315         .probe          = ad7766_probe,
 316         .id_table       = ad7766_id,
 317 };
 318 module_spi_driver(ad7766_driver);
 319
 320 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 321 MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support");
 322 MODULE_LICENSE("GPL v2");