// SPDX-License-Identifier: GPL-2.0+
/*
* AD7124 SPI ADC driver
*
* Copyright 2018 Analog Devices Inc.
*/
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <linux/iio/iio.h>
#include <linux/iio/adc/ad_sigma_delta.h>
#include <linux/iio/sysfs.h>
/* AD7124 registers */
#define AD7124_COMMS 0x00
#define AD7124_STATUS 0x00
#define AD7124_ADC_CONTROL 0x01
#define AD7124_DATA 0x02
#define AD7124_IO_CONTROL_1 0x03
#define AD7124_IO_CONTROL_2 0x04
#define AD7124_ID 0x05
#define AD7124_ERROR 0x06
#define AD7124_ERROR_EN 0x07
#define AD7124_MCLK_COUNT 0x08
#define AD7124_CHANNEL(x) (0x09 + (x))
#define AD7124_CONFIG(x) (0x19 + (x))
#define AD7124_FILTER(x) (0x21 + (x))
#define AD7124_OFFSET(x) (0x29 + (x))
#define AD7124_GAIN(x) (0x31 + (x))
/* AD7124_STATUS */
#define AD7124_STATUS_POR_FLAG_MSK BIT(4)
/* AD7124_ADC_CONTROL */
#define AD7124_ADC_CTRL_PWR_MSK GENMASK(7, 6)
#define AD7124_ADC_CTRL_PWR(x) FIELD_PREP(AD7124_ADC_CTRL_PWR_MSK, x)
#define AD7124_ADC_CTRL_MODE_MSK GENMASK(5, 2)
#define AD7124_ADC_CTRL_MODE(x) FIELD_PREP(AD7124_ADC_CTRL_MODE_MSK, x)
/* AD7124_CHANNEL_X */
#define AD7124_CHANNEL_EN_MSK BIT(15)
#define AD7124_CHANNEL_EN(x) FIELD_PREP(AD7124_CHANNEL_EN_MSK, x)
#define AD7124_CHANNEL_SETUP_MSK GENMASK(14, 12)
#define AD7124_CHANNEL_SETUP(x) FIELD_PREP(AD7124_CHANNEL_SETUP_MSK, x)
#define AD7124_CHANNEL_AINP_MSK GENMASK(9, 5)
#define AD7124_CHANNEL_AINP(x) FIELD_PREP(AD7124_CHANNEL_AINP_MSK, x)
#define AD7124_CHANNEL_AINM_MSK GENMASK(4, 0)
#define AD7124_CHANNEL_AINM(x) FIELD_PREP(AD7124_CHANNEL_AINM_MSK, x)
/* AD7124_CONFIG_X */
#define AD7124_CONFIG_BIPOLAR_MSK BIT(11)
#define AD7124_CONFIG_BIPOLAR(x) FIELD_PREP(AD7124_CONFIG_BIPOLAR_MSK, x)
#define AD7124_CONFIG_REF_SEL_MSK GENMASK(4, 3)
#define AD7124_CONFIG_REF_SEL(x) FIELD_PREP(AD7124_CONFIG_REF_SEL_MSK, x)
#define AD7124_CONFIG_PGA_MSK GENMASK(2, 0)
#define AD7124_CONFIG_PGA(x) FIELD_PREP(AD7124_CONFIG_PGA_MSK, x)
/* AD7124_FILTER_X */
#define AD7124_FILTER_FS_MSK GENMASK(10, 0)
#define AD7124_FILTER_FS(x) FIELD_PREP(AD7124_FILTER_FS_MSK, x)
enum ad7124_ids {
ID_AD7124_4,
ID_AD7124_8,
};
enum ad7124_ref_sel {
AD7124_REFIN1,
AD7124_REFIN2,
AD7124_INT_REF,
AD7124_AVDD_REF,
};
enum ad7124_power_mode {
AD7124_LOW_POWER,
AD7124_MID_POWER,
AD7124_FULL_POWER,
};
static const unsigned int ad7124_gain[8] = {
1, 2, 4, 8, 16, 32, 64, 128
};
static const int ad7124_master_clk_freq_hz[3] = {
[AD7124_LOW_POWER] = 76800,
[AD7124_MID_POWER] = 153600,
[AD7124_FULL_POWER] = 614400,
};
static const char * const ad7124_ref_names[] = {
[AD7124_REFIN1] = "refin1",
[AD7124_REFIN2] = "refin2",
[AD7124_INT_REF] = "int",
[AD7124_AVDD_REF] = "avdd",
};
struct ad7124_chip_info {
unsigned int num_inputs;
};
struct ad7124_channel_config {
enum ad7124_ref_sel refsel;
bool bipolar;
unsigned int ain;
unsigned int vref_mv;
unsigned int pga_bits;
unsigned int odr;
};
struct ad7124_state {
const struct ad7124_chip_info *chip_info;
struct ad_sigma_delta sd;
struct ad7124_channel_config channel_config[4];
struct regulator *vref[4];
struct clk *mclk;
unsigned int adc_control;
unsigned int num_channels;
};
static const struct iio_chan_spec ad7124_channel_template = {
.type = IIO_VOLTAGE,
.indexed = 1,
.differential = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_OFFSET) |
BIT(IIO_CHAN_INFO_SAMP_FREQ),
.scan_type = {
.sign = 'u',
.realbits = 24,
.storagebits = 32,
.shift = 8,
.endianness = IIO_BE,
},
};
static struct ad7124_chip_info ad7124_chip_info_tbl[] = {
[ID_AD7124_4] = {
.num_inputs = 8,
},
[ID_AD7124_8] = {
.num_inputs = 16,
},
};
static int ad7124_find_closest_match(const int *array,
unsigned int size, int val)
{
int i, idx;
unsigned int diff_new, diff_old;
diff_old = U32_MAX;
idx = 0;
for (i = 0; i < size; i++) {
diff_new = abs(val - array[i]);
if (diff_new < diff_old) {
diff_old = diff_new;
idx = i;
}
}
return idx;
}
static int ad7124_spi_write_mask(struct ad7124_state *st,
unsigned int addr,
unsigned long mask,
unsigned int val,
unsigned int bytes)
{
unsigned int readval;
int ret;
ret = ad_sd_read_reg(&st->sd, addr, bytes, &readval);
if (ret < 0)
return ret;
readval &= ~mask;
readval |= val;
return ad_sd_write_reg(&st->sd, addr, bytes, readval);
}
static int ad7124_set_mode(struct ad_sigma_delta *sd,
enum ad_sigma_delta_mode mode)
{
struct ad7124_state *st = container_of(sd, struct ad7124_state, sd);
st->adc_control &= ~AD7124_ADC_CTRL_MODE_MSK;
st->adc_control |= AD7124_ADC_CTRL_MODE(mode);
return ad_sd_write_reg(&st->sd, AD7124_ADC_CONTROL, 2, st->adc_control);
}
static int ad7124_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
{
struct ad7124_state *st = container_of(sd, struct ad7124_state, sd);
unsigned int val;
val = st->channel_config[channel].ain | AD7124_CHANNEL_EN(1) |
AD7124_CHANNEL_SETUP(channel);
return ad_sd_write_reg(&st->sd, AD7124_CHANNEL(channel), 2, val);
}
static const struct ad_sigma_delta_info ad7124_sigma_delta_info = {
.set_channel = ad7124_set_channel,
.set_mode = ad7124_set_mode,
.has_registers = true,
.addr_shift = 0,
.read_mask = BIT(6),
.data_reg = AD7124_DATA,
};
static int ad7124_set_channel_odr(struct ad7124_state *st,
unsigned int channel,
unsigned int odr)
{
unsigned int fclk, odr_sel_bits;
int ret;
fclk = clk_get_rate(st->mclk);
/*
* FS[10:0] = fCLK / (fADC x 32) where:
* fADC is the output data rate
* fCLK is the master clock frequency
* FS[10:0] are the bits in the filter register
* FS[10:0] can have a value from 1 to 2047
*/
odr_sel_bits = DIV_ROUND_CLOSEST(fclk, odr * 32);
if (odr_sel_bits < 1)
odr_sel_bits = 1;
else if (odr_sel_bits > 2047)
odr_sel_bits = 2047;
ret = ad7124_spi_write_mask(st, AD7124_FILTER(channel),
AD7124_FILTER_FS_MSK,
AD7124_FILTER_FS(odr_sel_bits), 3);
if (ret < 0)
return ret;
/* fADC = fCLK / (FS[10:0] x 32) */
st->channel_config[channel].odr =
DIV_ROUND_CLOSEST(fclk, odr_sel_bits * 32);
return 0;
}
static int ad7124_set_channel_gain(struct ad7124_state *st,
unsigned int channel,
unsigned int gain)
{
unsigned int res;
int ret;
res = ad7124_find_closest_match(ad7124_gain,
ARRAY_SIZE(ad7124_gain), gain);
ret = ad7124_spi_write_mask(st, AD7124_CONFIG(channel),
AD7124_CONFIG_PGA_MSK,
AD7124_CONFIG_PGA(res), 2);
if (ret < 0)
return ret;
st->channel_config[channel].pga_bits = res;
return 0;
}
static int ad7124_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long info)
{
struct ad7124_state *st = iio_priv(indio_dev);
int idx, ret;
switch (info) {
case IIO_CHAN_INFO_RAW:
ret = ad_sigma_delta_single_conversion(indio_dev, chan, val);
if (ret < 0)
return ret;
/* After the conversion is performed, disable the channel */
ret = ad_sd_write_reg(&st->sd,
AD7124_CHANNEL(chan->address), 2,
st->channel_config[chan->address].ain |
AD7124_CHANNEL_EN(0));
if (ret < 0)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
idx = st->channel_config[chan->address].pga_bits;
*val = st->channel_config[chan->address].vref_mv;
if (st->channel_config[chan->address].bipolar)
*val2 = chan->scan_type.realbits - 1 + idx;
else
*val2 = chan->scan_type.realbits + idx;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_OFFSET:
if (st->channel_config[chan->address].bipolar)
*val = -(1 << (chan->scan_type.realbits - 1));
else
*val = 0;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SAMP_FREQ:
*val = st->channel_config[chan->address].odr;
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static int ad7124_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long info)
{
struct ad7124_state *st = iio_priv(indio_dev);
unsigned int res, gain, full_scale, vref;
switch (info) {
case IIO_CHAN_INFO_SAMP_FREQ:
if (val2 != 0)
return -EINVAL;
return ad7124_set_channel_odr(st, chan->address, val);
case IIO_CHAN_INFO_SCALE:
if (val != 0)
return -EINVAL;
if (st->channel_config[chan->address].bipolar)
full_scale = 1 << (chan->scan_type.realbits - 1);
else
full_scale = 1 << chan->scan_type.realbits;
vref = st->channel_config[chan->address].vref_mv * 1000000LL;
res = DIV_ROUND_CLOSEST(vref, full_scale);
gain = DIV_ROUND_CLOSEST(res, val2);
return ad7124_set_channel_gain(st, chan->address, gain);
default:
return -EINVAL;
}
}
static IIO_CONST_ATTR(in_voltage_scale_available,
"0.000001164 0.000002328 0.000004656 0.000009313 0.000018626 0.000037252 0.000074505 0.000149011 0.000298023");
static struct attribute *ad7124_attributes[] = {
&iio_const_attr_in_voltage_scale_available.dev_attr.attr,
NULL,
};
static const struct attribute_group ad7124_attrs_group = {
.attrs = ad7124_attributes,
};
static const struct iio_info ad7124_info = {
.read_raw = ad7124_read_raw,
.write_raw = ad7124_write_raw,
.validate_trigger = ad_sd_validate_trigger,
.attrs = &ad7124_attrs_group,
};
static int ad7124_soft_reset(struct ad7124_state *st)
{
unsigned int readval, timeout;
int ret;
ret = ad_sd_reset(&st->sd, 64);
if (ret < 0)
return ret;
timeout = 100;
do {
ret = ad_sd_read_reg(&st->sd, AD7124_STATUS, 1, &readval);
if (ret < 0)
return ret;
if (!(readval & AD7124_STATUS_POR_FLAG_MSK))
return 0;
/* The AD7124 requires typically 2ms to power up and settle */
usleep_range(100, 2000);
} while (--timeout);
dev_err(&st->sd.spi->dev, "Soft reset failed\n");
return -EIO;
}
static int ad7124_init_channel_vref(struct ad7124_state *st,
unsigned int channel_number)
{
unsigned int refsel = st->channel_config[channel_number].refsel;
switch (refsel) {
case AD7124_REFIN1:
case AD7124_REFIN2:
case AD7124_AVDD_REF:
if (IS_ERR(st->vref[refsel])) {
dev_err(&st->sd.spi->dev,
"Error, trying to use external voltage reference without a %s regulator.\n",
ad7124_ref_names[refsel]);
return PTR_ERR(st->vref[refsel]);
}
st->channel_config[channel_number].vref_mv =
regulator_get_voltage(st->vref[refsel]);
/* Conversion from uV to mV */
st->channel_config[channel_number].vref_mv /= 1000;
break;
case AD7124_INT_REF:
st->channel_config[channel_number].vref_mv = 2500;
break;
default:
dev_err(&st->sd.spi->dev, "Invalid reference %d\n", refsel);
return -EINVAL;
}
return 0;
}
static int ad7124_of_parse_channel_config(struct iio_dev *indio_dev,
struct device_node *np)
{
struct ad7124_state *st = iio_priv(indio_dev);
struct device_node *child;
struct iio_chan_spec *chan;
unsigned int ain[2], channel = 0, tmp;
int ret;
st->num_channels = of_get_available_child_count(np);
if (!st->num_channels) {
dev_err(indio_dev->dev.parent, "no channel children\n");
return -ENODEV;
}
chan = devm_kcalloc(indio_dev->dev.parent, st->num_channels,
sizeof(*chan), GFP_KERNEL);
if (!chan)
return -ENOMEM;
indio_dev->channels = chan;
indio_dev->num_channels = st->num_channels;
for_each_available_child_of_node(np, child) {
ret = of_property_read_u32(child, "reg", &channel);
if (ret)
goto err;
ret = of_property_read_u32_array(child, "diff-channels",
ain, 2);
if (ret)
goto err;
if (ain[0] >= st->chip_info->num_inputs ||
ain[1] >= st->chip_info->num_inputs) {
dev_err(indio_dev->dev.parent,
"Input pin number out of range.\n");
ret = -EINVAL;
goto err;
}
st->channel_config[channel].ain = AD7124_CHANNEL_AINP(ain[0]) |
AD7124_CHANNEL_AINM(ain[1]);
st->channel_config[channel].bipolar =
of_property_read_bool(child, "bipolar");
ret = of_property_read_u32(child, "adi,reference-select", &tmp);
if (ret)
st->channel_config[channel].refsel = AD7124_INT_REF;
else
st->channel_config[channel].refsel = tmp;
*chan = ad7124_channel_template;
chan->address = channel;
chan->scan_index = channel;
chan->channel = ain[0];
chan->channel2 = ain[1];
chan++;
}
return 0;
err:
of_node_put(child);
return ret;
}
static int ad7124_setup(struct ad7124_state *st)
{
unsigned int val, fclk, power_mode;
int i, ret;
fclk = clk_get_rate(st->mclk);
if (!fclk)
return -EINVAL;
/* The power mode changes the master clock frequency */
power_mode = ad7124_find_closest_match(ad7124_master_clk_freq_hz,
ARRAY_SIZE(ad7124_master_clk_freq_hz),
fclk);
if (fclk != ad7124_master_clk_freq_hz[power_mode]) {
ret = clk_set_rate(st->mclk, fclk);
if (ret)
return ret;
}
/* Set the power mode */
st->adc_control &= ~AD7124_ADC_CTRL_PWR_MSK;
st->adc_control |= AD7124_ADC_CTRL_PWR(power_mode);
ret = ad_sd_write_reg(&st->sd, AD7124_ADC_CONTROL, 2, st->adc_control);
if (ret < 0)
return ret;
for (i = 0; i < st->num_channels; i++) {
val = st->channel_config[i].ain | AD7124_CHANNEL_SETUP(i);
ret = ad_sd_write_reg(&st->sd, AD7124_CHANNEL(i), 2, val);
if (ret < 0)
return ret;
ret = ad7124_init_channel_vref(st, i);
if (ret < 0)
return ret;
val = AD7124_CONFIG_BIPOLAR(st->channel_config[i].bipolar) |
AD7124_CONFIG_REF_SEL(st->channel_config[i].refsel);
ret = ad_sd_write_reg(&st->sd, AD7124_CONFIG(i), 2, val);
if (ret < 0)
return ret;
/*
* 9.38 SPS is the minimum output data rate supported
* regardless of the selected power mode. Round it up to 10 and
* set all the enabled channels to this default value.
*/
ret = ad7124_set_channel_odr(st, i, 10);
}
return ret;
}
static int ad7124_probe(struct spi_device *spi)
{
const struct spi_device_id *id;
struct ad7124_state *st;
struct iio_dev *indio_dev;
int i, ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
id = spi_get_device_id(spi);
st->chip_info = &ad7124_chip_info_tbl[id->driver_data];
ad_sd_init(&st->sd, indio_dev, spi, &ad7124_sigma_delta_info);
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->info = &ad7124_info;
ret = ad7124_of_parse_channel_config(indio_dev, spi->dev.of_node);
if (ret < 0)
return ret;
for (i = 0; i < ARRAY_SIZE(st->vref); i++) {
if (i == AD7124_INT_REF)
continue;
st->vref[i] = devm_regulator_get_optional(&spi->dev,
ad7124_ref_names[i]);
if (PTR_ERR(st->vref[i]) == -ENODEV)
continue;
else if (IS_ERR(st->vref[i]))
return PTR_ERR(st->vref[i]);
ret = regulator_enable(st->vref[i]);
if (ret)
return ret;
}
st->mclk = devm_clk_get(&spi->dev, "mclk");
if (IS_ERR(st->mclk)) {
ret = PTR_ERR(st->mclk);
goto error_regulator_disable;
}
ret = clk_prepare_enable(st->mclk);
if (ret < 0)
goto error_regulator_disable;
ret = ad7124_soft_reset(st);
if (ret < 0)
goto error_clk_disable_unprepare;
ret = ad7124_setup(st);
if (ret < 0)
goto error_clk_disable_unprepare;
ret = ad_sd_setup_buffer_and_trigger(indio_dev);
if (ret < 0)
goto error_clk_disable_unprepare;
ret = iio_device_register(indio_dev);
if (ret < 0) {
dev_err(&spi->dev, "Failed to register iio device\n");
goto error_remove_trigger;
}
return 0;
error_remove_trigger:
ad_sd_cleanup_buffer_and_trigger(indio_dev);
error_clk_disable_unprepare:
clk_disable_unprepare(st->mclk);
error_regulator_disable:
for (i = ARRAY_SIZE(st->vref) - 1; i >= 0; i--) {
if (!IS_ERR_OR_NULL(st->vref[i]))
regulator_disable(st->vref[i]);
}
return ret;
}
static int ad7124_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct ad7124_state *st = iio_priv(indio_dev);
int i;
iio_device_unregister(indio_dev);
ad_sd_cleanup_buffer_and_trigger(indio_dev);
clk_disable_unprepare(st->mclk);
for (i = ARRAY_SIZE(st->vref) - 1; i >= 0; i--) {
if (!IS_ERR_OR_NULL(st->vref[i]))
regulator_disable(st->vref[i]);
}
return 0;
}
static const struct spi_device_id ad7124_id_table[] = {
{ "ad7124-4", ID_AD7124_4 },
{ "ad7124-8", ID_AD7124_8 },
{}
};
MODULE_DEVICE_TABLE(spi, ad7124_id_table);
static const struct of_device_id ad7124_of_match[] = {
{ .compatible = "adi,ad7124-4" },
{ .compatible = "adi,ad7124-8" },
{ },
};
MODULE_DEVICE_TABLE(of, ad7124_of_match);
static struct spi_driver ad71124_driver = {
.driver = {
.name = "ad7124",
.of_match_table = ad7124_of_match,
},
.probe = ad7124_probe,
.remove = ad7124_remove,
.id_table = ad7124_id_table,
};
module_spi_driver(ad71124_driver);
MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD7124 SPI driver");
MODULE_LICENSE("GPL");