root/drivers/iio/dac/ad5770r.c
// SPDX-License-Identifier: GPL-2.0+
/*
 * AD5770R Digital to analog converters driver
 *
 * Copyright 2018 Analog Devices Inc.
 */

#include <linux/bits.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <linux/unaligned.h>

#define ADI_SPI_IF_CONFIG_A             0x00
#define ADI_SPI_IF_CONFIG_B             0x01
#define ADI_SPI_IF_DEVICE_CONFIG        0x02
#define ADI_SPI_IF_CHIP_TYPE            0x03
#define ADI_SPI_IF_PRODUCT_ID_L         0x04
#define ADI_SPI_IF_PRODUCT_ID_H         0x05
#define ADI_SPI_IF_CHIP_GRADE           0x06
#define ADI_SPI_IF_SCRACTH_PAD          0x0A
#define ADI_SPI_IF_SPI_REVISION         0x0B
#define ADI_SPI_IF_SPI_VENDOR_L         0x0C
#define ADI_SPI_IF_SPI_VENDOR_H         0x0D
#define ADI_SPI_IF_SPI_STREAM_MODE      0x0E
#define ADI_SPI_IF_CONFIG_C             0x10
#define ADI_SPI_IF_STATUS_A             0x11

/* ADI_SPI_IF_CONFIG_A */
#define ADI_SPI_IF_SW_RESET_MSK         (BIT(0) | BIT(7))
#define ADI_SPI_IF_SW_RESET_SEL(x)      ((x) & ADI_SPI_IF_SW_RESET_MSK)
#define ADI_SPI_IF_ADDR_ASC_MSK         (BIT(2) | BIT(5))
#define ADI_SPI_IF_ADDR_ASC_SEL(x)      (((x) << 2) & ADI_SPI_IF_ADDR_ASC_MSK)

/* ADI_SPI_IF_CONFIG_B */
#define ADI_SPI_IF_SINGLE_INS_MSK       BIT(7)
#define ADI_SPI_IF_SINGLE_INS_SEL(x)    FIELD_PREP(ADI_SPI_IF_SINGLE_INS_MSK, x)
#define ADI_SPI_IF_SHORT_INS_MSK        BIT(7)
#define ADI_SPI_IF_SHORT_INS_SEL(x)     FIELD_PREP(ADI_SPI_IF_SINGLE_INS_MSK, x)

/* ADI_SPI_IF_CONFIG_C */
#define ADI_SPI_IF_STRICT_REG_MSK       BIT(5)
#define ADI_SPI_IF_STRICT_REG_GET(x)    FIELD_GET(ADI_SPI_IF_STRICT_REG_MSK, x)

/* AD5770R configuration registers */
#define AD5770R_CHANNEL_CONFIG          0x14
#define AD5770R_OUTPUT_RANGE(ch)        (0x15 + (ch))
#define AD5770R_FILTER_RESISTOR(ch)     (0x1D + (ch))
#define AD5770R_REFERENCE               0x1B
#define AD5770R_DAC_LSB(ch)             (0x26 + 2 * (ch))
#define AD5770R_DAC_MSB(ch)             (0x27 + 2 * (ch))
#define AD5770R_CH_SELECT               0x34
#define AD5770R_CH_ENABLE               0x44

/* AD5770R_CHANNEL_CONFIG */
#define AD5770R_CFG_CH0_SINK_EN(x)              (((x) & 0x1) << 7)
#define AD5770R_CFG_SHUTDOWN_B(x, ch)           (((x) & 0x1) << (ch))

/* AD5770R_OUTPUT_RANGE */
#define AD5770R_RANGE_OUTPUT_SCALING(x)         (((x) & GENMASK(5, 0)) << 2)
#define AD5770R_RANGE_MODE(x)                   ((x) & GENMASK(1, 0))

/* AD5770R_REFERENCE */
#define AD5770R_REF_RESISTOR_SEL(x)             (((x) & 0x1) << 2)
#define AD5770R_REF_SEL(x)                      ((x) & GENMASK(1, 0))

/* AD5770R_CH_ENABLE */
#define AD5770R_CH_SET(x, ch)           (((x) & 0x1) << (ch))

#define AD5770R_MAX_CHANNELS    6
#define AD5770R_MAX_CH_MODES    14
#define AD5770R_LOW_VREF_mV     1250
#define AD5770R_HIGH_VREF_mV    2500

enum ad5770r_ch0_modes {
        AD5770R_CH0_0_300 = 0,
        AD5770R_CH0_NEG_60_0,
        AD5770R_CH0_NEG_60_300
};

enum ad5770r_ch1_modes {
        AD5770R_CH1_0_140_LOW_HEAD = 1,
        AD5770R_CH1_0_140_LOW_NOISE,
        AD5770R_CH1_0_250
};

enum ad5770r_ch2_5_modes {
        AD5770R_CH_LOW_RANGE = 0,
        AD5770R_CH_HIGH_RANGE
};

enum ad5770r_ref_v {
        AD5770R_EXT_2_5_V = 0,
        AD5770R_INT_1_25_V_OUT_ON,
        AD5770R_EXT_1_25_V,
        AD5770R_INT_1_25_V_OUT_OFF
};

enum ad5770r_output_filter_resistor {
        AD5770R_FILTER_60_OHM = 0x0,
        AD5770R_FILTER_5_6_KOHM = 0x5,
        AD5770R_FILTER_11_2_KOHM,
        AD5770R_FILTER_22_2_KOHM,
        AD5770R_FILTER_44_4_KOHM,
        AD5770R_FILTER_104_KOHM,
};

struct ad5770r_out_range {
        u8      out_scale;
        u8      out_range_mode;
};

/**
 * struct ad5770r_state - driver instance specific data
 * @spi:                spi_device
 * @regmap:             regmap
 * @gpio_reset:         gpio descriptor
 * @output_mode:        array contains channels output ranges
 * @vref:               reference value
 * @ch_pwr_down:        powerdown flags
 * @internal_ref:       internal reference flag
 * @external_res:       external 2.5k resistor flag
 * @transf_buf:         cache aligned buffer for spi read/write
 */
struct ad5770r_state {
        struct spi_device               *spi;
        struct regmap                   *regmap;
        struct gpio_desc                *gpio_reset;
        struct ad5770r_out_range        output_mode[AD5770R_MAX_CHANNELS];
        int                             vref;
        bool                            ch_pwr_down[AD5770R_MAX_CHANNELS];
        bool                            internal_ref;
        bool                            external_res;
        u8                              transf_buf[2] __aligned(IIO_DMA_MINALIGN);
};

static const struct regmap_config ad5770r_spi_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .read_flag_mask = BIT(7),
};

struct ad5770r_output_modes {
        unsigned int ch;
        u8 mode;
        int min;
        int max;
};

static const struct ad5770r_output_modes ad5770r_rng_tbl[] = {
        { 0, AD5770R_CH0_0_300, 0, 300 },
        { 0, AD5770R_CH0_NEG_60_0, -60, 0 },
        { 0, AD5770R_CH0_NEG_60_300, -60, 300 },
        { 1, AD5770R_CH1_0_140_LOW_HEAD, 0, 140 },
        { 1, AD5770R_CH1_0_140_LOW_NOISE, 0, 140 },
        { 1, AD5770R_CH1_0_250, 0, 250 },
        { 2, AD5770R_CH_LOW_RANGE, 0, 55 },
        { 2, AD5770R_CH_HIGH_RANGE, 0, 150 },
        { 3, AD5770R_CH_LOW_RANGE, 0, 45 },
        { 3, AD5770R_CH_HIGH_RANGE, 0, 100 },
        { 4, AD5770R_CH_LOW_RANGE, 0, 45 },
        { 4, AD5770R_CH_HIGH_RANGE, 0, 100 },
        { 5, AD5770R_CH_LOW_RANGE, 0, 45 },
        { 5, AD5770R_CH_HIGH_RANGE, 0, 100 },
};

static const unsigned int ad5770r_filter_freqs[] = {
        153, 357, 715, 1400, 2800, 262000,
};

static const unsigned int ad5770r_filter_reg_vals[] = {
        AD5770R_FILTER_104_KOHM,
        AD5770R_FILTER_44_4_KOHM,
        AD5770R_FILTER_22_2_KOHM,
        AD5770R_FILTER_11_2_KOHM,
        AD5770R_FILTER_5_6_KOHM,
        AD5770R_FILTER_60_OHM
};

static int ad5770r_set_output_mode(struct ad5770r_state *st,
                                   const struct ad5770r_out_range *out_mode,
                                   int channel)
{
        unsigned int regval;

        regval = AD5770R_RANGE_OUTPUT_SCALING(out_mode->out_scale) |
                 AD5770R_RANGE_MODE(out_mode->out_range_mode);

        return regmap_write(st->regmap,
                            AD5770R_OUTPUT_RANGE(channel), regval);
}

static int ad5770r_set_reference(struct ad5770r_state *st)
{
        unsigned int regval;

        regval = AD5770R_REF_RESISTOR_SEL(st->external_res);

        if (st->internal_ref) {
                regval |= AD5770R_REF_SEL(AD5770R_INT_1_25_V_OUT_OFF);
        } else {
                switch (st->vref) {
                case AD5770R_LOW_VREF_mV:
                        regval |= AD5770R_REF_SEL(AD5770R_EXT_1_25_V);
                        break;
                case AD5770R_HIGH_VREF_mV:
                        regval |= AD5770R_REF_SEL(AD5770R_EXT_2_5_V);
                        break;
                default:
                        regval = AD5770R_REF_SEL(AD5770R_INT_1_25_V_OUT_OFF);
                        break;
                }
        }

        return regmap_write(st->regmap, AD5770R_REFERENCE, regval);
}

static int ad5770r_soft_reset(struct ad5770r_state *st)
{
        return regmap_write(st->regmap, ADI_SPI_IF_CONFIG_A,
                            ADI_SPI_IF_SW_RESET_SEL(1));
}

static int ad5770r_reset(struct ad5770r_state *st)
{
        /* Perform software reset if no GPIO provided */
        if (!st->gpio_reset)
                return ad5770r_soft_reset(st);

        gpiod_set_value_cansleep(st->gpio_reset, 0);
        usleep_range(10, 20);
        gpiod_set_value_cansleep(st->gpio_reset, 1);

        /* data must not be written during reset timeframe */
        usleep_range(100, 200);

        return 0;
}

static int ad5770r_get_range(struct ad5770r_state *st,
                             int ch, int *min, int *max)
{
        int i;
        u8 tbl_ch, tbl_mode, out_range;

        out_range = st->output_mode[ch].out_range_mode;

        for (i = 0; i < AD5770R_MAX_CH_MODES; i++) {
                tbl_ch = ad5770r_rng_tbl[i].ch;
                tbl_mode = ad5770r_rng_tbl[i].mode;
                if (tbl_ch == ch && tbl_mode == out_range) {
                        *min = ad5770r_rng_tbl[i].min;
                        *max = ad5770r_rng_tbl[i].max;
                        return 0;
                }
        }

        return -EINVAL;
}

static int ad5770r_get_filter_freq(struct iio_dev *indio_dev,
                                   const struct iio_chan_spec *chan, int *freq)
{
        struct ad5770r_state *st = iio_priv(indio_dev);
        int ret;
        unsigned int regval, i;

        ret = regmap_read(st->regmap,
                          AD5770R_FILTER_RESISTOR(chan->channel), &regval);
        if (ret < 0)
                return ret;

        for (i = 0; i < ARRAY_SIZE(ad5770r_filter_reg_vals); i++)
                if (regval == ad5770r_filter_reg_vals[i])
                        break;
        if (i == ARRAY_SIZE(ad5770r_filter_reg_vals))
                return -EINVAL;

        *freq = ad5770r_filter_freqs[i];

        return IIO_VAL_INT;
}

static int ad5770r_set_filter_freq(struct iio_dev *indio_dev,
                                   const struct iio_chan_spec *chan,
                                   unsigned int freq)
{
        struct ad5770r_state *st = iio_priv(indio_dev);
        unsigned int regval, i;

        for (i = 0; i < ARRAY_SIZE(ad5770r_filter_freqs); i++)
                if (ad5770r_filter_freqs[i] >= freq)
                        break;
        if (i == ARRAY_SIZE(ad5770r_filter_freqs))
                return -EINVAL;

        regval = ad5770r_filter_reg_vals[i];

        return regmap_write(st->regmap, AD5770R_FILTER_RESISTOR(chan->channel),
                            regval);
}

static int ad5770r_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long info)
{
        struct ad5770r_state *st = iio_priv(indio_dev);
        int max, min, ret;
        u16 buf16;

        switch (info) {
        case IIO_CHAN_INFO_RAW:
                ret = regmap_bulk_read(st->regmap,
                                       chan->address,
                                       st->transf_buf, 2);
                if (ret)
                        return ret;

                buf16 = get_unaligned_le16(st->transf_buf);
                *val = buf16 >> 2;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                ret = ad5770r_get_range(st, chan->channel, &min, &max);
                if (ret < 0)
                        return ret;
                *val = max - min;
                /* There is no sign bit. (negative current is mapped from 0)
                 * (sourced/sinked) current = raw * scale + offset
                 * where offset in case of CH0 can be negative.
                 */
                *val2 = 14;
                return IIO_VAL_FRACTIONAL_LOG2;
        case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
                return ad5770r_get_filter_freq(indio_dev, chan, val);
        case IIO_CHAN_INFO_OFFSET:
                ret = ad5770r_get_range(st, chan->channel, &min, &max);
                if (ret < 0)
                        return ret;
                *val = min;
                return IIO_VAL_INT;
        default:
                return -EINVAL;
        }
}

static int ad5770r_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long info)
{
        struct ad5770r_state *st = iio_priv(indio_dev);

        switch (info) {
        case IIO_CHAN_INFO_RAW:
                st->transf_buf[0] = ((u16)val >> 6);
                st->transf_buf[1] = (val & GENMASK(5, 0)) << 2;
                return regmap_bulk_write(st->regmap, chan->address,
                                         st->transf_buf, 2);
        case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
                return ad5770r_set_filter_freq(indio_dev, chan, val);
        default:
                return -EINVAL;
        }
}

static int ad5770r_read_freq_avail(struct iio_dev *indio_dev,
                                   struct iio_chan_spec const *chan,
                                   const int **vals, int *type, int *length,
                                   long mask)
{
        switch (mask) {
        case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
                *type = IIO_VAL_INT;
                *vals = ad5770r_filter_freqs;
                *length = ARRAY_SIZE(ad5770r_filter_freqs);
                return IIO_AVAIL_LIST;
        }

        return -EINVAL;
}

static int ad5770r_reg_access(struct iio_dev *indio_dev,
                              unsigned int reg,
                              unsigned int writeval,
                              unsigned int *readval)
{
        struct ad5770r_state *st = iio_priv(indio_dev);

        if (readval)
                return regmap_read(st->regmap, reg, readval);
        else
                return regmap_write(st->regmap, reg, writeval);
}

static const struct iio_info ad5770r_info = {
        .read_raw = ad5770r_read_raw,
        .write_raw = ad5770r_write_raw,
        .read_avail = ad5770r_read_freq_avail,
        .debugfs_reg_access = &ad5770r_reg_access,
};

static int ad5770r_store_output_range(struct ad5770r_state *st,
                                      int min, int max, int index)
{
        int i;

        for (i = 0; i < AD5770R_MAX_CH_MODES; i++) {
                if (ad5770r_rng_tbl[i].ch != index)
                        continue;
                if (ad5770r_rng_tbl[i].min != min ||
                    ad5770r_rng_tbl[i].max != max)
                        continue;
                st->output_mode[index].out_range_mode = ad5770r_rng_tbl[i].mode;

                return 0;
        }

        return -EINVAL;
}

static ssize_t ad5770r_read_dac_powerdown(struct iio_dev *indio_dev,
                                          uintptr_t private,
                                          const struct iio_chan_spec *chan,
                                          char *buf)
{
        struct ad5770r_state *st = iio_priv(indio_dev);

        return sysfs_emit(buf, "%d\n", st->ch_pwr_down[chan->channel]);
}

static ssize_t ad5770r_write_dac_powerdown(struct iio_dev *indio_dev,
                                           uintptr_t private,
                                           const struct iio_chan_spec *chan,
                                           const char *buf, size_t len)
{
        struct ad5770r_state *st = iio_priv(indio_dev);
        unsigned int regval;
        unsigned int mask;
        bool readin;
        int ret;

        ret = kstrtobool(buf, &readin);
        if (ret)
                return ret;

        readin = !readin;

        regval = AD5770R_CFG_SHUTDOWN_B(readin, chan->channel);
        if (chan->channel == 0 &&
            st->output_mode[0].out_range_mode > AD5770R_CH0_0_300) {
                regval |= AD5770R_CFG_CH0_SINK_EN(readin);
                mask = BIT(chan->channel) + BIT(7);
        } else {
                mask = BIT(chan->channel);
        }
        ret = regmap_update_bits(st->regmap, AD5770R_CHANNEL_CONFIG, mask,
                                 regval);
        if (ret)
                return ret;

        regval = AD5770R_CH_SET(readin, chan->channel);
        ret = regmap_update_bits(st->regmap, AD5770R_CH_ENABLE,
                                 BIT(chan->channel), regval);
        if (ret)
                return ret;

        st->ch_pwr_down[chan->channel] = !readin;

        return len;
}

static const struct iio_chan_spec_ext_info ad5770r_ext_info[] = {
        {
                .name = "powerdown",
                .read = ad5770r_read_dac_powerdown,
                .write = ad5770r_write_dac_powerdown,
                .shared = IIO_SEPARATE,
        },
        { }
};

#define AD5770R_IDAC_CHANNEL(index, reg) {                              \
        .type = IIO_CURRENT,                                            \
        .address = reg,                                                 \
        .indexed = 1,                                                   \
        .channel = index,                                               \
        .output = 1,                                                    \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |                  \
                BIT(IIO_CHAN_INFO_SCALE) |                              \
                BIT(IIO_CHAN_INFO_OFFSET) |                             \
                BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),       \
        .info_mask_shared_by_type_available =                           \
                BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),       \
        .ext_info = ad5770r_ext_info,                                   \
}

static const struct iio_chan_spec ad5770r_channels[] = {
        AD5770R_IDAC_CHANNEL(0, AD5770R_DAC_MSB(0)),
        AD5770R_IDAC_CHANNEL(1, AD5770R_DAC_MSB(1)),
        AD5770R_IDAC_CHANNEL(2, AD5770R_DAC_MSB(2)),
        AD5770R_IDAC_CHANNEL(3, AD5770R_DAC_MSB(3)),
        AD5770R_IDAC_CHANNEL(4, AD5770R_DAC_MSB(4)),
        AD5770R_IDAC_CHANNEL(5, AD5770R_DAC_MSB(5)),
};

static int ad5770r_channel_config(struct ad5770r_state *st)
{
        int ret, tmp[2], min, max;
        unsigned int num;

        num = device_get_child_node_count(&st->spi->dev);
        if (num != AD5770R_MAX_CHANNELS)
                return -EINVAL;

        device_for_each_child_node_scoped(&st->spi->dev, child) {
                ret = fwnode_property_read_u32(child, "reg", &num);
                if (ret)
                        return ret;
                if (num >= AD5770R_MAX_CHANNELS)
                        return -EINVAL;

                ret = fwnode_property_read_u32_array(child,
                                                     "adi,range-microamp",
                                                     tmp, 2);
                if (ret)
                        return ret;

                min = tmp[0] / 1000;
                max = tmp[1] / 1000;
                ret = ad5770r_store_output_range(st, min, max, num);
                if (ret)
                        return ret;
        }

        return 0;
}

static int ad5770r_init(struct ad5770r_state *st)
{
        int ret, i;

        st->gpio_reset = devm_gpiod_get_optional(&st->spi->dev, "reset",
                                                 GPIOD_OUT_HIGH);
        if (IS_ERR(st->gpio_reset))
                return PTR_ERR(st->gpio_reset);

        /* Perform a reset */
        ret = ad5770r_reset(st);
        if (ret)
                return ret;

        /* Set output range */
        ret = ad5770r_channel_config(st);
        if (ret)
                return ret;

        for (i = 0; i < AD5770R_MAX_CHANNELS; i++) {
                ret = ad5770r_set_output_mode(st,  &st->output_mode[i], i);
                if (ret)
                        return ret;
        }

        st->external_res = fwnode_property_read_bool(st->spi->dev.fwnode,
                                                     "adi,external-resistor");

        ret = ad5770r_set_reference(st);
        if (ret)
                return ret;

        /* Set outputs off */
        ret = regmap_write(st->regmap, AD5770R_CHANNEL_CONFIG, 0x00);
        if (ret)
                return ret;

        ret = regmap_write(st->regmap, AD5770R_CH_ENABLE, 0x00);
        if (ret)
                return ret;

        for (i = 0; i < AD5770R_MAX_CHANNELS; i++)
                st->ch_pwr_down[i] = true;

        return ret;
}

static int ad5770r_probe(struct spi_device *spi)
{
        struct ad5770r_state *st;
        struct iio_dev *indio_dev;
        struct regmap *regmap;
        int ret;

        indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
        if (!indio_dev)
                return -ENOMEM;

        st = iio_priv(indio_dev);
        spi_set_drvdata(spi, indio_dev);

        st->spi = spi;

        regmap = devm_regmap_init_spi(spi, &ad5770r_spi_regmap_config);
        if (IS_ERR(regmap)) {
                dev_err(&spi->dev, "Error initializing spi regmap: %ld\n",
                        PTR_ERR(regmap));
                return PTR_ERR(regmap);
        }
        st->regmap = regmap;

        ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");
        if (ret < 0 && ret != -ENODEV)
                return dev_err_probe(&spi->dev, ret, "Failed to get vref voltage\n");

        st->internal_ref = ret == -ENODEV;
        st->vref = st->internal_ref ? AD5770R_LOW_VREF_mV : ret / 1000;

        indio_dev->name = spi_get_device_id(spi)->name;
        indio_dev->info = &ad5770r_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = ad5770r_channels;
        indio_dev->num_channels = ARRAY_SIZE(ad5770r_channels);

        ret = ad5770r_init(st);
        if (ret < 0) {
                dev_err(&spi->dev, "AD5770R init failed\n");
                return ret;
        }

        return devm_iio_device_register(&st->spi->dev, indio_dev);
}

static const struct of_device_id ad5770r_of_id[] = {
        { .compatible = "adi,ad5770r", },
        { }
};
MODULE_DEVICE_TABLE(of, ad5770r_of_id);

static const struct spi_device_id ad5770r_id[] = {
        { "ad5770r", 0 },
        { }
};
MODULE_DEVICE_TABLE(spi, ad5770r_id);

static struct spi_driver ad5770r_driver = {
        .driver = {
                .name = KBUILD_MODNAME,
                .of_match_table = ad5770r_of_id,
        },
        .probe = ad5770r_probe,
        .id_table = ad5770r_id,
};

module_spi_driver(ad5770r_driver);

MODULE_AUTHOR("Mircea Caprioru <mircea.caprioru@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD5770R IDAC");
MODULE_LICENSE("GPL v2");