linux/drivers/iio/adc/ad7766.c
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   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
  24struct ad7766_chip_info {
  25        unsigned int decimation_factor;
  26};
  27
  28enum {
  29        AD7766_SUPPLY_AVDD = 0,
  30        AD7766_SUPPLY_DVDD = 1,
  31        AD7766_SUPPLY_VREF = 2,
  32        AD7766_NUM_SUPPLIES = 3
  33};
  34
  35struct 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 */
  61enum ad7766_device_ids {
  62        ID_AD7766,
  63        ID_AD7766_1,
  64        ID_AD7766_2,
  65};
  66
  67static 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);
  80done:
  81        iio_trigger_notify_done(indio_dev->trig);
  82
  83        return IRQ_HANDLED;
  84}
  85
  86static 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
 110static 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
 128static 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
 151static 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
 167static 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
 179static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = {
 180        .preenable = &ad7766_preenable,
 181        .postdisable = &ad7766_postdisable,
 182};
 183
 184static const struct iio_info ad7766_info = {
 185        .read_raw = &ad7766_read_raw,
 186};
 187
 188static irqreturn_t ad7766_irq(int irq, void *private)
 189{
 190        iio_trigger_poll(private);
 191        return IRQ_HANDLED;
 192}
 193
 194static 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
 206static 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
 211static 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
 300static 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};
 309MODULE_DEVICE_TABLE(spi, ad7766_id);
 310
 311static struct spi_driver ad7766_driver = {
 312        .driver = {
 313                .name   = "ad7766",
 314        },
 315        .probe          = ad7766_probe,
 316        .id_table       = ad7766_id,
 317};
 318module_spi_driver(ad7766_driver);
 319
 320MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 321MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support");
 322MODULE_LICENSE("GPL v2");
 323