iio/adc/ad7780.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * AD7170/AD7171 and AD7780/AD7781 SPI ADC driver
0004  *
0005  * Copyright 2011 Analog Devices Inc.
0006  * Copyright 2019 Renato Lui Geh
0007  */
0008
0009 #include <linux/interrupt.h>
0010 #include <linux/device.h>
0011 #include <linux/kernel.h>
0012 #include <linux/slab.h>
0013 #include <linux/sysfs.h>
0014 #include <linux/spi/spi.h>
0015 #include <linux/regulator/consumer.h>
0016 #include <linux/err.h>
0017 #include <linux/sched.h>
0018 #include <linux/gpio/consumer.h>
0019 #include <linux/module.h>
0020 #include <linux/bits.h>
0021
0022 #include <linux/iio/iio.h>
0023 #include <linux/iio/sysfs.h>
0024 #include <linux/iio/adc/ad_sigma_delta.h>
0025
0026 #define AD7780_RDY      BIT(7)
0027 #define AD7780_FILTER       BIT(6)
0028 #define AD7780_ERR      BIT(5)
0029 #define AD7780_ID1      BIT(4)
0030 #define AD7780_ID0      BIT(3)
0031 #define AD7780_GAIN     BIT(2)
0032
0033 #define AD7170_ID       0
0034 #define AD7171_ID       1
0035 #define AD7780_ID       1
0036 #define AD7781_ID       0
0037
0038 #define AD7780_ID_MASK      (AD7780_ID0 | AD7780_ID1)
0039
0040 #define AD7780_PATTERN_GOOD 1
0041 #define AD7780_PATTERN_MASK GENMASK(1, 0)
0042
0043 #define AD7170_PATTERN_GOOD 5
0044 #define AD7170_PATTERN_MASK GENMASK(2, 0)
0045
0046 #define AD7780_GAIN_MIDPOINT    64
0047 #define AD7780_FILTER_MIDPOINT  13350
0048
0049 static const unsigned int ad778x_gain[2]      = { 1, 128 };
0050 static const unsigned int ad778x_odr_avail[2] = { 10000, 16700 };
0051
0052 struct ad7780_chip_info {
0053     struct iio_chan_spec    channel;
0054     unsigned int        pattern_mask;
0055     unsigned int        pattern;
0056     bool            is_ad778x;
0057 };
0058
0059 struct ad7780_state {
0060     const struct ad7780_chip_info   *chip_info;
0061     struct regulator        *reg;
0062     struct gpio_desc        *powerdown_gpio;
0063     struct gpio_desc        *gain_gpio;
0064     struct gpio_desc        *filter_gpio;
0065     unsigned int            gain;
0066     unsigned int            odr;
0067     unsigned int            int_vref_mv;
0068
0069     struct ad_sigma_delta sd;
0070 };
0071
0072 enum ad7780_supported_device_ids {
0073     ID_AD7170,
0074     ID_AD7171,
0075     ID_AD7780,
0076     ID_AD7781,
0077 };
0078
0079 static struct ad7780_state *ad_sigma_delta_to_ad7780(struct ad_sigma_delta *sd)
0080 {
0081     return container_of(sd, struct ad7780_state, sd);
0082 }
0083
0084 static int ad7780_set_mode(struct ad_sigma_delta *sigma_delta,
0085                enum ad_sigma_delta_mode mode)
0086 {
0087     struct ad7780_state *st = ad_sigma_delta_to_ad7780(sigma_delta);
0088     unsigned int val;
0089
0090     switch (mode) {
0091     case AD_SD_MODE_SINGLE:
0092     case AD_SD_MODE_CONTINUOUS:
0093         val = 1;
0094         break;
0095     default:
0096         val = 0;
0097         break;
0098     }
0099
0100     gpiod_set_value(st->powerdown_gpio, val);
0101
0102     return 0;
0103 }
0104
0105 static int ad7780_read_raw(struct iio_dev *indio_dev,
0106                struct iio_chan_spec const *chan,
0107                int *val,
0108                int *val2,
0109                long m)
0110 {
0111     struct ad7780_state *st = iio_priv(indio_dev);
0112     int voltage_uv;
0113
0114     switch (m) {
0115     case IIO_CHAN_INFO_RAW:
0116         return ad_sigma_delta_single_conversion(indio_dev, chan, val);
0117     case IIO_CHAN_INFO_SCALE:
0118         voltage_uv = regulator_get_voltage(st->reg);
0119         if (voltage_uv < 0)
0120             return voltage_uv;
0121         voltage_uv /= 1000;
0122         *val = voltage_uv * st->gain;
0123         *val2 = chan->scan_type.realbits - 1;
0124         st->int_vref_mv = voltage_uv;
0125         return IIO_VAL_FRACTIONAL_LOG2;
0126     case IIO_CHAN_INFO_OFFSET:
0127         *val = -(1 << (chan->scan_type.realbits - 1));
0128         return IIO_VAL_INT;
0129     case IIO_CHAN_INFO_SAMP_FREQ:
0130         *val = st->odr;
0131         return IIO_VAL_INT;
0132     default:
0133         break;
0134     }
0135
0136     return -EINVAL;
0137 }
0138
0139 static int ad7780_write_raw(struct iio_dev *indio_dev,
0140                 struct iio_chan_spec const *chan,
0141                 int val,
0142                 int val2,
0143                 long m)
0144 {
0145     struct ad7780_state *st = iio_priv(indio_dev);
0146     const struct ad7780_chip_info *chip_info = st->chip_info;
0147     unsigned long long vref;
0148     unsigned int full_scale, gain;
0149
0150     if (!chip_info->is_ad778x)
0151         return -EINVAL;
0152
0153     switch (m) {
0154     case IIO_CHAN_INFO_SCALE:
0155         if (val != 0)
0156             return -EINVAL;
0157
0158         vref = st->int_vref_mv * 1000000LL;
0159         full_scale = 1 << (chip_info->channel.scan_type.realbits - 1);
0160         gain = DIV_ROUND_CLOSEST_ULL(vref, full_scale);
0161         gain = DIV_ROUND_CLOSEST(gain, val2);
0162         st->gain = gain;
0163         if (gain < AD7780_GAIN_MIDPOINT)
0164             gain = 0;
0165         else
0166             gain = 1;
0167         gpiod_set_value(st->gain_gpio, gain);
0168         break;
0169     case IIO_CHAN_INFO_SAMP_FREQ:
0170         if (1000*val + val2/1000 < AD7780_FILTER_MIDPOINT)
0171             val = 0;
0172         else
0173             val = 1;
0174         st->odr = ad778x_odr_avail[val];
0175         gpiod_set_value(st->filter_gpio, val);
0176         break;
0177     default:
0178         break;
0179     }
0180
0181     return 0;
0182 }
0183
0184 static int ad7780_postprocess_sample(struct ad_sigma_delta *sigma_delta,
0185                      unsigned int raw_sample)
0186 {
0187     struct ad7780_state *st = ad_sigma_delta_to_ad7780(sigma_delta);
0188     const struct ad7780_chip_info *chip_info = st->chip_info;
0189
0190     if ((raw_sample & AD7780_ERR) ||
0191         ((raw_sample & chip_info->pattern_mask) != chip_info->pattern))
0192         return -EIO;
0193
0194     if (chip_info->is_ad778x) {
0195         st->gain = ad778x_gain[raw_sample & AD7780_GAIN];
0196         st->odr = ad778x_odr_avail[raw_sample & AD7780_FILTER];
0197     }
0198
0199     return 0;
0200 }
0201
0202 static const struct ad_sigma_delta_info ad7780_sigma_delta_info = {
0203     .set_mode = ad7780_set_mode,
0204     .postprocess_sample = ad7780_postprocess_sample,
0205     .has_registers = false,
0206     .irq_flags = IRQF_TRIGGER_FALLING,
0207 };
0208
0209 #define _AD7780_CHANNEL(_bits, _wordsize, _mask_all)        \
0210 {                               \
0211     .type = IIO_VOLTAGE,                    \
0212     .indexed = 1,                       \
0213     .channel = 0,                       \
0214     .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |      \
0215         BIT(IIO_CHAN_INFO_OFFSET),          \
0216     .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
0217     .info_mask_shared_by_all = _mask_all,           \
0218     .scan_index = 1,                    \
0219     .scan_type = {                      \
0220         .sign = 'u',                    \
0221         .realbits = (_bits),                \
0222         .storagebits = 32,              \
0223         .shift = (_wordsize) - (_bits),         \
0224         .endianness = IIO_BE,               \
0225     },                          \
0226 }
0227
0228 #define AD7780_CHANNEL(_bits, _wordsize)    \
0229     _AD7780_CHANNEL(_bits, _wordsize, BIT(IIO_CHAN_INFO_SAMP_FREQ))
0230 #define AD7170_CHANNEL(_bits, _wordsize)    \
0231     _AD7780_CHANNEL(_bits, _wordsize, 0)
0232
0233 static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
0234     [ID_AD7170] = {
0235         .channel = AD7170_CHANNEL(12, 24),
0236         .pattern = AD7170_PATTERN_GOOD,
0237         .pattern_mask = AD7170_PATTERN_MASK,
0238         .is_ad778x = false,
0239     },
0240     [ID_AD7171] = {
0241         .channel = AD7170_CHANNEL(16, 24),
0242         .pattern = AD7170_PATTERN_GOOD,
0243         .pattern_mask = AD7170_PATTERN_MASK,
0244         .is_ad778x = false,
0245     },
0246     [ID_AD7780] = {
0247         .channel = AD7780_CHANNEL(24, 32),
0248         .pattern = AD7780_PATTERN_GOOD,
0249         .pattern_mask = AD7780_PATTERN_MASK,
0250         .is_ad778x = true,
0251     },
0252     [ID_AD7781] = {
0253         .channel = AD7780_CHANNEL(20, 32),
0254         .pattern = AD7780_PATTERN_GOOD,
0255         .pattern_mask = AD7780_PATTERN_MASK,
0256         .is_ad778x = true,
0257     },
0258 };
0259
0260 static const struct iio_info ad7780_info = {
0261     .read_raw = ad7780_read_raw,
0262     .write_raw = ad7780_write_raw,
0263 };
0264
0265 static int ad7780_init_gpios(struct device *dev, struct ad7780_state *st)
0266 {
0267     int ret;
0268
0269     st->powerdown_gpio = devm_gpiod_get_optional(dev,
0270                              "powerdown",
0271                              GPIOD_OUT_LOW);
0272     if (IS_ERR(st->powerdown_gpio)) {
0273         ret = PTR_ERR(st->powerdown_gpio);
0274         dev_err(dev, "Failed to request powerdown GPIO: %d\n", ret);
0275         return ret;
0276     }
0277
0278     if (!st->chip_info->is_ad778x)
0279         return 0;
0280
0281
0282     st->gain_gpio = devm_gpiod_get_optional(dev,
0283                         "adi,gain",
0284                         GPIOD_OUT_HIGH);
0285     if (IS_ERR(st->gain_gpio)) {
0286         ret = PTR_ERR(st->gain_gpio);
0287         dev_err(dev, "Failed to request gain GPIO: %d\n", ret);
0288         return ret;
0289     }
0290
0291     st->filter_gpio = devm_gpiod_get_optional(dev,
0292                           "adi,filter",
0293                           GPIOD_OUT_HIGH);
0294     if (IS_ERR(st->filter_gpio)) {
0295         ret = PTR_ERR(st->filter_gpio);
0296         dev_err(dev, "Failed to request filter GPIO: %d\n", ret);
0297         return ret;
0298     }
0299
0300     return 0;
0301 }
0302
0303 static void ad7780_reg_disable(void *reg)
0304 {
0305     regulator_disable(reg);
0306 }
0307
0308 static int ad7780_probe(struct spi_device *spi)
0309 {
0310     struct ad7780_state *st;
0311     struct iio_dev *indio_dev;
0312     int ret;
0313
0314     indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
0315     if (!indio_dev)
0316         return -ENOMEM;
0317
0318     st = iio_priv(indio_dev);
0319     st->gain = 1;
0320
0321     ad_sd_init(&st->sd, indio_dev, spi, &ad7780_sigma_delta_info);
0322
0323     st->chip_info =
0324         &ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
0325
0326     indio_dev->name = spi_get_device_id(spi)->name;
0327     indio_dev->modes = INDIO_DIRECT_MODE;
0328     indio_dev->channels = &st->chip_info->channel;
0329     indio_dev->num_channels = 1;
0330     indio_dev->info = &ad7780_info;
0331
0332     ret = ad7780_init_gpios(&spi->dev, st);
0333     if (ret)
0334         return ret;
0335
0336     st->reg = devm_regulator_get(&spi->dev, "avdd");
0337     if (IS_ERR(st->reg))
0338         return PTR_ERR(st->reg);
0339
0340     ret = regulator_enable(st->reg);
0341     if (ret) {
0342         dev_err(&spi->dev, "Failed to enable specified AVdd supply\n");
0343         return ret;
0344     }
0345
0346     ret = devm_add_action_or_reset(&spi->dev, ad7780_reg_disable, st->reg);
0347     if (ret)
0348         return ret;
0349
0350     ret = devm_ad_sd_setup_buffer_and_trigger(&spi->dev, indio_dev);
0351     if (ret)
0352         return ret;
0353
0354     return devm_iio_device_register(&spi->dev, indio_dev);
0355 }
0356
0357 static const struct spi_device_id ad7780_id[] = {
0358     {"ad7170", ID_AD7170},
0359     {"ad7171", ID_AD7171},
0360     {"ad7780", ID_AD7780},
0361     {"ad7781", ID_AD7781},
0362     {}
0363 };
0364 MODULE_DEVICE_TABLE(spi, ad7780_id);
0365
0366 static struct spi_driver ad7780_driver = {
0367     .driver = {
0368         .name   = "ad7780",
0369     },
0370     .probe      = ad7780_probe,
0371     .id_table   = ad7780_id,
0372 };
0373 module_spi_driver(ad7780_driver);
0374
0375 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
0376 MODULE_DESCRIPTION("Analog Devices AD7780 and similar ADCs");
0377 MODULE_LICENSE("GPL v2");
0378 MODULE_IMPORT_NS(IIO_AD_SIGMA_DELTA);