+
+#define AD7780_GAIN_GPIO 0
+#define AD7780_FILTER_GPIO 1
+
+#define AD7780_GAIN_MIDPOINT 64
+#define AD7780_FILTER_MIDPOINT 13350
+
+static const unsigned int ad778x_gain[2] = { 1, 128 };
+static const unsigned int ad778x_odr_avail[2] = { 10000, 16700 };
+
+struct ad7780_chip_info {
+ struct iio_chan_spec channel;
+ unsigned int pattern_mask;
+ unsigned int pattern;
+ bool is_ad778x;
+};
+
+struct ad7780_state {
+ const struct ad7780_chip_info *chip_info;
+ struct regulator *reg;
+ struct gpio_desc *powerdown_gpio;
+ struct gpio_desc *gain_gpio;
+ struct gpio_desc *filter_gpio;
+ unsigned int gain;
+ unsigned int odr;
+ unsigned int int_vref_mv;
+
+ struct ad_sigma_delta sd;
+};
+
+enum ad7780_supported_device_ids {
+ ID_AD7170,
+ ID_AD7171,
+ ID_AD7780,
+ ID_AD7781,
+};
+
+static struct ad7780_state *ad_sigma_delta_to_ad7780(struct ad_sigma_delta *sd)
+{
+ return container_of(sd, struct ad7780_state, sd);
+}
+
+static int ad7780_set_mode(struct ad_sigma_delta *sigma_delta,
+ enum ad_sigma_delta_mode mode)
+{
+ struct ad7780_state *st = ad_sigma_delta_to_ad7780(sigma_delta);
+ unsigned int val;
+
+ switch (mode) {
+ case AD_SD_MODE_SINGLE:
+ case AD_SD_MODE_CONTINUOUS:
+ val = 1;
+ break;
+ default:
+ val = 0;
+ break;
+ }
+
+ gpiod_set_value(st->powerdown_gpio, val);
+
+ return 0;
+}
+
+static int ad7780_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val,
+ int *val2,
+ long m)
+{
+ struct ad7780_state *st = iio_priv(indio_dev);
+ int voltage_uv;
+
+ switch (m) {
+ case IIO_CHAN_INFO_RAW:
+ return ad_sigma_delta_single_conversion(indio_dev, chan, val);
+ case IIO_CHAN_INFO_SCALE:
+ voltage_uv = regulator_get_voltage(st->reg);
+ if (voltage_uv < 0)
+ return voltage_uv;
+ voltage_uv /= 1000;
+ *val = voltage_uv * st->gain;
+ *val2 = chan->scan_type.realbits - 1;
+ st->int_vref_mv = voltage_uv;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CHAN_INFO_OFFSET:
+ *val = -(1 << (chan->scan_type.realbits - 1));
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = st->odr;
+ return IIO_VAL_INT;
+ }
+
+ return -EINVAL;
+}
+
+static int ad7780_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val,
+ int val2,
+ long m)
+{
+ struct ad7780_state *st = iio_priv(indio_dev);
+ const struct ad7780_chip_info *chip_info = st->chip_info;
+ unsigned long long vref;
+ unsigned int full_scale, gain;
+
+ if (!chip_info->is_ad778x)
+ return 0;
+
+ switch (m) {
+ case IIO_CHAN_INFO_SCALE:
+ if (val != 0)
+ return -EINVAL;
+
+ vref = st->int_vref_mv * 1000000LL;
+ full_scale = 1 << (chip_info->channel.scan_type.realbits - 1);
+ gain = DIV_ROUND_CLOSEST(vref, full_scale);
+ gain = DIV_ROUND_CLOSEST(gain, val2);
+ st->gain = gain;
+ if (gain < AD7780_GAIN_MIDPOINT)
+ gain = 0;
+ else
+ gain = 1;
+ gpiod_set_value(st->gain_gpio, gain);
+ break;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ if (1000*val + val2/1000 < AD7780_FILTER_MIDPOINT)
+ val = 0;
+ else
+ val = 1;
+ st->odr = ad778x_odr_avail[val];
+ gpiod_set_value(st->filter_gpio, val);
+ break;
+ }
+
+ return 0;
+}
+
+static int ad7780_postprocess_sample(struct ad_sigma_delta *sigma_delta,
+ unsigned int raw_sample)
+{
+ struct ad7780_state *st = ad_sigma_delta_to_ad7780(sigma_delta);
+ const struct ad7780_chip_info *chip_info = st->chip_info;
+
+ if ((raw_sample & AD7780_ERR) ||
+ ((raw_sample & chip_info->pattern_mask) != chip_info->pattern))
+ return -EIO;
+
+ if (chip_info->is_ad778x) {
+ st->gain = ad778x_gain[raw_sample & AD7780_GAIN];
+ st->odr = ad778x_odr_avail[raw_sample & AD7780_FILTER];
+ }
+
+ return 0;
+}
+
+static const struct ad_sigma_delta_info ad7780_sigma_delta_info = {
+ .set_mode = ad7780_set_mode,
+ .postprocess_sample = ad7780_postprocess_sample,
+ .has_registers = false,
+};
+
+#define AD7780_CHANNEL(bits, wordsize) \
+ AD_SD_CHANNEL_NO_SAMP_FREQ(1, 0, 0, bits, 32, wordsize - bits)
+
+static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
+ [ID_AD7170] = {
+ .channel = AD7780_CHANNEL(12, 24),
+ .pattern = AD7170_PATTERN,
+ .pattern_mask = AD7170_PATTERN_MASK,
+ .is_ad778x = false,
+ },
+ [ID_AD7171] = {
+ .channel = AD7780_CHANNEL(16, 24),
+ .pattern = AD7170_PATTERN,
+ .pattern_mask = AD7170_PATTERN_MASK,
+ .is_ad778x = false,
+ },
+ [ID_AD7780] = {
+ .channel = AD7780_CHANNEL(24, 32),
+ .pattern = AD7780_PATTERN,
+ .pattern_mask = AD7780_PATTERN_MASK,
+ .is_ad778x = true,
+ },
+ [ID_AD7781] = {
+ .channel = AD7780_CHANNEL(20, 32),
+ .pattern = AD7780_PATTERN,
+ .pattern_mask = AD7780_PATTERN_MASK,
+ .is_ad778x = true,
+ },
+};
+
+static const struct iio_info ad7780_info = {
+ .read_raw = ad7780_read_raw,
+ .write_raw = ad7780_write_raw,
+};
+
+static int ad7780_probe(struct spi_device *spi)
+{
+ struct ad7780_state *st;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+ st->gain = 1;
+
+ ad_sd_init(&st->sd, indio_dev, spi, &ad7780_sigma_delta_info);
+
+ st->chip_info =
+ &ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+ spi_set_drvdata(spi, indio_dev);
+
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = &st->chip_info->channel;
+ indio_dev->num_channels = 1;
+ indio_dev->info = &ad7780_info;
+
+ st->powerdown_gpio = devm_gpiod_get_optional(&spi->dev,
+ "powerdown",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(st->powerdown_gpio)) {
+ ret = PTR_ERR(st->powerdown_gpio);
+ dev_err(&spi->dev, "Failed to request powerdown GPIO: %d\n",
+ ret);
+ return ret;
+ }
+
+ if (st->chip_info->is_ad778x) {
+ st->gain_gpio = devm_gpiod_get_optional(&spi->dev,
+ "gain",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(st->gain_gpio)) {
+ ret = PTR_ERR(st->gain_gpio);
+ dev_err(&spi->dev, "Failed to request gain GPIO: %d\n",
+ ret);
+ return ret;
+ }
+
+ st->filter_gpio = devm_gpiod_get_optional(&spi->dev,
+ "filter",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(st->filter_gpio)) {
+ ret = PTR_ERR(st->filter_gpio);
+ dev_err(&spi->dev,
+ "Failed to request filter GPIO: %d\n",
+ ret);
+ return ret;
+ }
+ }
+
+ st->reg = devm_regulator_get(&spi->dev, "avdd");
+ if (IS_ERR(st->reg))
+ return PTR_ERR(st->reg);
+
+ ret = regulator_enable(st->reg);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to enable specified AVdd supply\n");
+ return ret;
+ }
+
+ ret = ad_sd_setup_buffer_and_trigger(indio_dev);
+ if (ret)
+ goto error_disable_reg;
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ goto error_cleanup_buffer_and_trigger;
+
+ return 0;
+
+error_cleanup_buffer_and_trigger:
+ ad_sd_cleanup_buffer_and_trigger(indio_dev);
+error_disable_reg:
+ regulator_disable(st->reg);
+
+ return ret;
+}
+
+static int ad7780_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct ad7780_state *st = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ ad_sd_cleanup_buffer_and_trigger(indio_dev);
+
+ regulator_disable(st->reg);
+
+ return 0;
+}
+
+static const struct spi_device_id ad7780_id[] = {
+ {"ad7170", ID_AD7170},
+ {"ad7171", ID_AD7171},
+ {"ad7780", ID_AD7780},
+ {"ad7781", ID_AD7781},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, ad7780_id);
+
+static struct spi_driver ad7780_driver = {
+ .driver = {
+ .name = "ad7780",
+ },
+ .probe = ad7780_probe,
+ .remove = ad7780_remove,
+ .id_table = ad7780_id,
+};
+module_spi_driver(ad7780_driver);
+
+MODULE_AUTHOR("Michael Hennerich <michael.hennerich@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Analog Devices AD7780 and similar ADCs");
+MODULE_LICENSE("GPL v2");
