// SPDX-License-Identifier: GPL-2.0
/*
* LTC2664 4 channel, 12-/16-Bit Voltage Output SoftSpan DAC driver
* LTC2672 5 channel, 12-/16-Bit Current Output Softspan DAC driver
*
* Copyright 2024 Analog Devices Inc.
*/
#include <linux/bitfield.h>
#include <linux/cleanup.h>
#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/iio/iio.h>
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/mutex.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#define LTC2664_CMD_WRITE_N(n) (0x00 + (n))
#define LTC2664_CMD_UPDATE_N(n) (0x10 + (n))
#define LTC2664_CMD_WRITE_N_UPDATE_ALL 0x20
#define LTC2664_CMD_WRITE_N_UPDATE_N(n) (0x30 + (n))
#define LTC2664_CMD_POWER_DOWN_N(n) (0x40 + (n))
#define LTC2664_CMD_POWER_DOWN_ALL 0x50
#define LTC2664_CMD_SPAN_N(n) (0x60 + (n))
#define LTC2664_CMD_CONFIG 0x70
#define LTC2664_CMD_MUX 0xB0
#define LTC2664_CMD_TOGGLE_SEL 0xC0
#define LTC2664_CMD_GLOBAL_TOGGLE 0xD0
#define LTC2664_CMD_NO_OPERATION 0xF0
#define LTC2664_REF_DISABLE 0x0001
#define LTC2664_MSPAN_SOFTSPAN 7
#define LTC2672_MAX_CHANNEL 5
#define LTC2672_MAX_SPAN 7
#define LTC2672_SCALE_MULTIPLIER(n) (50 * BIT(n))
enum {
LTC2664_SPAN_RANGE_0V_5V,
LTC2664_SPAN_RANGE_0V_10V,
LTC2664_SPAN_RANGE_M5V_5V,
LTC2664_SPAN_RANGE_M10V_10V,
LTC2664_SPAN_RANGE_M2V5_2V5,
};
enum {
LTC2664_INPUT_A,
LTC2664_INPUT_B,
LTC2664_INPUT_B_AVAIL,
LTC2664_POWERDOWN,
LTC2664_POWERDOWN_MODE,
LTC2664_TOGGLE_EN,
LTC2664_GLOBAL_TOGGLE,
};
static const u16 ltc2664_mspan_lut[8][2] = {
{ LTC2664_SPAN_RANGE_M10V_10V, 32768 }, /* MPS2=0, MPS1=0, MSP0=0 (0)*/
{ LTC2664_SPAN_RANGE_M5V_5V, 32768 }, /* MPS2=0, MPS1=0, MSP0=1 (1)*/
{ LTC2664_SPAN_RANGE_M2V5_2V5, 32768 }, /* MPS2=0, MPS1=1, MSP0=0 (2)*/
{ LTC2664_SPAN_RANGE_0V_10V, 0 }, /* MPS2=0, MPS1=1, MSP0=1 (3)*/
{ LTC2664_SPAN_RANGE_0V_10V, 32768 }, /* MPS2=1, MPS1=0, MSP0=0 (4)*/
{ LTC2664_SPAN_RANGE_0V_5V, 0 }, /* MPS2=1, MPS1=0, MSP0=1 (5)*/
{ LTC2664_SPAN_RANGE_0V_5V, 32768 }, /* MPS2=1, MPS1=1, MSP0=0 (6)*/
{ LTC2664_SPAN_RANGE_0V_5V, 0 } /* MPS2=1, MPS1=1, MSP0=1 (7)*/
};
struct ltc2664_state;
struct ltc2664_chip_info {
const char *name;
int (*scale_get)(const struct ltc2664_state *st, int c);
int (*offset_get)(const struct ltc2664_state *st, int c);
int measurement_type;
unsigned int num_channels;
const int (*span_helper)[2];
unsigned int num_span;
unsigned int internal_vref_mv;
bool manual_span_support;
bool rfsadj_support;
};
struct ltc2664_chan {
/* indicates if the channel should be toggled */
bool toggle_chan;
/* indicates if the channel is in powered down state */
bool powerdown;
/* span code of the channel */
u8 span;
/* raw data of the current state of the chip registers (A/B) */
u16 raw[2];
};
struct ltc2664_state {
struct spi_device *spi;
struct regmap *regmap;
struct ltc2664_chan channels[LTC2672_MAX_CHANNEL];
/* lock to protect against multiple access to the device and shared data */
struct mutex lock;
const struct ltc2664_chip_info *chip_info;
struct iio_chan_spec *iio_channels;
int vref_mv;
u32 rfsadj_ohms;
u32 toggle_sel;
bool global_toggle;
};
static const int ltc2664_span_helper[][2] = {
{ 0, 5000 },
{ 0, 10000 },
{ -5000, 5000 },
{ -10000, 10000 },
{ -2500, 2500 },
};
static const int ltc2672_span_helper[][2] = {
{ 0, 0 },
{ 0, 3125 },
{ 0, 6250 },
{ 0, 12500 },
{ 0, 25000 },
{ 0, 50000 },
{ 0, 100000 },
{ 0, 200000 },
{ 0, 300000 },
};
static int ltc2664_scale_get(const struct ltc2664_state *st, int c)
{
const struct ltc2664_chan *chan = &st->channels[c];
const int (*span_helper)[2] = st->chip_info->span_helper;
int span, fs;
span = chan->span;
if (span < 0)
return span;
fs = span_helper[span][1] - span_helper[span][0];
return fs * st->vref_mv / 2500;
}
static int ltc2672_scale_get(const struct ltc2664_state *st, int c)
{
const struct ltc2664_chan *chan = &st->channels[c];
int span, fs;
span = chan->span - 1;
if (span < 0)
return span;
fs = 1000 * st->vref_mv;
if (span == LTC2672_MAX_SPAN)
return mul_u64_u32_div(4800, fs, st->rfsadj_ohms);
return mul_u64_u32_div(LTC2672_SCALE_MULTIPLIER(span), fs, st->rfsadj_ohms);
}
static int ltc2664_offset_get(const struct ltc2664_state *st, int c)
{
const struct ltc2664_chan *chan = &st->channels[c];
int span;
span = chan->span;
if (span < 0)
return span;
if (st->chip_info->span_helper[span][0] < 0)
return -32768;
return 0;
}
static int ltc2664_dac_code_write(struct ltc2664_state *st, u32 chan, u32 input,
u16 code)
{
struct ltc2664_chan *c = &st->channels[chan];
int ret, reg;
guard(mutex)(&st->lock);
/* select the correct input register to write to */
if (c->toggle_chan) {
ret = regmap_write(st->regmap, LTC2664_CMD_TOGGLE_SEL,
input << chan);
if (ret)
return ret;
}
/*
* If in toggle mode the dac should be updated by an
* external signal (or sw toggle) and not here.
*/
if (st->toggle_sel & BIT(chan))
reg = LTC2664_CMD_WRITE_N(chan);
else
reg = LTC2664_CMD_WRITE_N_UPDATE_N(chan);
ret = regmap_write(st->regmap, reg, code);
if (ret)
return ret;
c->raw[input] = code;
if (c->toggle_chan) {
ret = regmap_write(st->regmap, LTC2664_CMD_TOGGLE_SEL,
st->toggle_sel);
if (ret)
return ret;
}
return 0;
}
static void ltc2664_dac_code_read(struct ltc2664_state *st, u32 chan, u32 input,
u32 *code)
{
guard(mutex)(&st->lock);
*code = st->channels[chan].raw[input];
}
static const int ltc2664_raw_range[] = { 0, 1, U16_MAX };
static int ltc2664_read_avail(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
const int **vals, int *type, int *length,
long info)
{
switch (info) {
case IIO_CHAN_INFO_RAW:
*vals = ltc2664_raw_range;
*type = IIO_VAL_INT;
return IIO_AVAIL_RANGE;
default:
return -EINVAL;
}
}
static int ltc2664_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long info)
{
struct ltc2664_state *st = iio_priv(indio_dev);
switch (info) {
case IIO_CHAN_INFO_RAW:
ltc2664_dac_code_read(st, chan->channel, LTC2664_INPUT_A, val);
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
*val = st->chip_info->offset_get(st, chan->channel);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = st->chip_info->scale_get(st, chan->channel);
*val2 = 16;
return IIO_VAL_FRACTIONAL_LOG2;
default:
return -EINVAL;
}
}
static int ltc2664_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val,
int val2, long info)
{
struct ltc2664_state *st = iio_priv(indio_dev);
switch (info) {
case IIO_CHAN_INFO_RAW:
if (val > U16_MAX || val < 0)
return -EINVAL;
return ltc2664_dac_code_write(st, chan->channel,
LTC2664_INPUT_A, val);
default:
return -EINVAL;
}
}
static ssize_t ltc2664_reg_bool_get(struct iio_dev *indio_dev,
uintptr_t private,
const struct iio_chan_spec *chan,
char *buf)
{
struct ltc2664_state *st = iio_priv(indio_dev);
u32 val;
guard(mutex)(&st->lock);
switch (private) {
case LTC2664_POWERDOWN:
val = st->channels[chan->channel].powerdown;
return sysfs_emit(buf, "%u\n", val);
case LTC2664_POWERDOWN_MODE:
return sysfs_emit(buf, "42kohm_to_gnd\n");
case LTC2664_TOGGLE_EN:
val = !!(st->toggle_sel & BIT(chan->channel));
return sysfs_emit(buf, "%u\n", val);
case LTC2664_GLOBAL_TOGGLE:
val = st->global_toggle;
return sysfs_emit(buf, "%u\n", val);
default:
return -EINVAL;
}
}
static ssize_t ltc2664_reg_bool_set(struct iio_dev *indio_dev,
uintptr_t private,
const struct iio_chan_spec *chan,
const char *buf, size_t len)
{
struct ltc2664_state *st = iio_priv(indio_dev);
int ret;
bool en;
ret = kstrtobool(buf, &en);
if (ret)
return ret;
guard(mutex)(&st->lock);
switch (private) {
case LTC2664_POWERDOWN:
ret = regmap_write(st->regmap,
en ? LTC2664_CMD_POWER_DOWN_N(chan->channel) :
LTC2664_CMD_UPDATE_N(chan->channel), en);
if (ret)
return ret;
st->channels[chan->channel].powerdown = en;
return len;
case LTC2664_TOGGLE_EN:
if (en)
st->toggle_sel |= BIT(chan->channel);
else
st->toggle_sel &= ~BIT(chan->channel);
ret = regmap_write(st->regmap, LTC2664_CMD_TOGGLE_SEL,
st->toggle_sel);
if (ret)
return ret;
return len;
case LTC2664_GLOBAL_TOGGLE:
ret = regmap_write(st->regmap, LTC2664_CMD_GLOBAL_TOGGLE, en);
if (ret)
return ret;
st->global_toggle = en;
return len;
default:
return -EINVAL;
}
}
static ssize_t ltc2664_dac_input_read(struct iio_dev *indio_dev,
uintptr_t private,
const struct iio_chan_spec *chan,
char *buf)
{
struct ltc2664_state *st = iio_priv(indio_dev);
u32 val;
if (private == LTC2664_INPUT_B_AVAIL)
return sysfs_emit(buf, "[%u %u %u]\n", ltc2664_raw_range[0],
ltc2664_raw_range[1],
ltc2664_raw_range[2] / 4);
ltc2664_dac_code_read(st, chan->channel, private, &val);
return sysfs_emit(buf, "%u\n", val);
}
static ssize_t ltc2664_dac_input_write(struct iio_dev *indio_dev,
uintptr_t private,
const struct iio_chan_spec *chan,
const char *buf, size_t len)
{
struct ltc2664_state *st = iio_priv(indio_dev);
int ret;
u16 val;
if (private == LTC2664_INPUT_B_AVAIL)
return -EINVAL;
ret = kstrtou16(buf, 10, &val);
if (ret)
return ret;
ret = ltc2664_dac_code_write(st, chan->channel, private, val);
if (ret)
return ret;
return len;
}
static int ltc2664_reg_access(struct iio_dev *indio_dev,
unsigned int reg,
unsigned int writeval,
unsigned int *readval)
{
struct ltc2664_state *st = iio_priv(indio_dev);
if (readval)
return -EOPNOTSUPP;
return regmap_write(st->regmap, reg, writeval);
}
#define LTC2664_CHAN_EXT_INFO(_name, _what, _shared, _read, _write) { \
.name = _name, \
.read = (_read), \
.write = (_write), \
.private = (_what), \
.shared = (_shared), \
}
/*
* For toggle mode we only expose the symbol attr (sw_toggle) in case a TGPx is
* not provided in dts.
*/
static const struct iio_chan_spec_ext_info ltc2664_toggle_sym_ext_info[] = {
LTC2664_CHAN_EXT_INFO("raw0", LTC2664_INPUT_A, IIO_SEPARATE,
ltc2664_dac_input_read, ltc2664_dac_input_write),
LTC2664_CHAN_EXT_INFO("raw1", LTC2664_INPUT_B, IIO_SEPARATE,
ltc2664_dac_input_read, ltc2664_dac_input_write),
LTC2664_CHAN_EXT_INFO("powerdown", LTC2664_POWERDOWN, IIO_SEPARATE,
ltc2664_reg_bool_get, ltc2664_reg_bool_set),
LTC2664_CHAN_EXT_INFO("powerdown_mode", LTC2664_POWERDOWN_MODE,
IIO_SEPARATE, ltc2664_reg_bool_get, NULL),
LTC2664_CHAN_EXT_INFO("symbol", LTC2664_GLOBAL_TOGGLE, IIO_SEPARATE,
ltc2664_reg_bool_get, ltc2664_reg_bool_set),
LTC2664_CHAN_EXT_INFO("toggle_en", LTC2664_TOGGLE_EN,
IIO_SEPARATE, ltc2664_reg_bool_get,
ltc2664_reg_bool_set),
{ }
};
static const struct iio_chan_spec_ext_info ltc2664_ext_info[] = {
LTC2664_CHAN_EXT_INFO("powerdown", LTC2664_POWERDOWN, IIO_SEPARATE,
ltc2664_reg_bool_get, ltc2664_reg_bool_set),
LTC2664_CHAN_EXT_INFO("powerdown_mode", LTC2664_POWERDOWN_MODE,
IIO_SEPARATE, ltc2664_reg_bool_get, NULL),
{ }
};
static const struct iio_chan_spec ltc2664_channel_template = {
.indexed = 1,
.output = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_OFFSET) |
BIT(IIO_CHAN_INFO_RAW),
.info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW),
.ext_info = ltc2664_ext_info,
};
static const struct ltc2664_chip_info ltc2664_chip = {
.name = "ltc2664",
.scale_get = ltc2664_scale_get,
.offset_get = ltc2664_offset_get,
.measurement_type = IIO_VOLTAGE,
.num_channels = 4,
.span_helper = ltc2664_span_helper,
.num_span = ARRAY_SIZE(ltc2664_span_helper),
.internal_vref_mv = 2500,
.manual_span_support = true,
.rfsadj_support = false,
};
static const struct ltc2664_chip_info ltc2672_chip = {
.name = "ltc2672",
.scale_get = ltc2672_scale_get,
.offset_get = ltc2664_offset_get,
.measurement_type = IIO_CURRENT,
.num_channels = 5,
.span_helper = ltc2672_span_helper,
.num_span = ARRAY_SIZE(ltc2672_span_helper),
.internal_vref_mv = 1250,
.manual_span_support = false,
.rfsadj_support = true,
};
static int ltc2664_set_span(const struct ltc2664_state *st, int min, int max,
int chan)
{
const struct ltc2664_chip_info *chip_info = st->chip_info;
const int (*span_helper)[2] = chip_info->span_helper;
int span, ret;
for (span = 0; span < chip_info->num_span; span++) {
if (min == span_helper[span][0] && max == span_helper[span][1])
break;
}
if (span == chip_info->num_span)
return -EINVAL;
ret = regmap_write(st->regmap, LTC2664_CMD_SPAN_N(chan), span);
if (ret)
return ret;
return span;
}
static int ltc2664_channel_config(struct ltc2664_state *st)
{
const struct ltc2664_chip_info *chip_info = st->chip_info;
struct device *dev = &st->spi->dev;
u32 reg, tmp[2], mspan;
int ret, span = 0;
mspan = LTC2664_MSPAN_SOFTSPAN;
ret = device_property_read_u32(dev, "adi,manual-span-operation-config",
&mspan);
if (!ret) {
if (!chip_info->manual_span_support)
return dev_err_probe(dev, -EINVAL,
"adi,manual-span-operation-config not supported\n");
if (mspan >= ARRAY_SIZE(ltc2664_mspan_lut))
return dev_err_probe(dev, -EINVAL,
"adi,manual-span-operation-config not in range\n");
}
st->rfsadj_ohms = 20000;
ret = device_property_read_u32(dev, "adi,rfsadj-ohms", &st->rfsadj_ohms);
if (!ret) {
if (!chip_info->rfsadj_support)
return dev_err_probe(dev, -EINVAL,
"adi,rfsadj-ohms not supported\n");
if (st->rfsadj_ohms < 19000 || st->rfsadj_ohms > 41000)
return dev_err_probe(dev, -EINVAL,
"adi,rfsadj-ohms not in range\n");
}
device_for_each_child_node_scoped(dev, child) {
struct ltc2664_chan *chan;
ret = fwnode_property_read_u32(child, "reg", ®);
if (ret)
return dev_err_probe(dev, ret,
"Failed to get reg property\n");
if (reg >= chip_info->num_channels)
return dev_err_probe(dev, -EINVAL,
"reg bigger than: %d\n",
chip_info->num_channels);
chan = &st->channels[reg];
if (fwnode_property_read_bool(child, "adi,toggle-mode")) {
chan->toggle_chan = true;
/* assume sw toggle ABI */
st->iio_channels[reg].ext_info = ltc2664_toggle_sym_ext_info;
/*
* Clear IIO_CHAN_INFO_RAW bit as toggle channels expose
* out_voltage/current_raw{0|1} files.
*/
__clear_bit(IIO_CHAN_INFO_RAW,
&st->iio_channels[reg].info_mask_separate);
}
chan->raw[0] = ltc2664_mspan_lut[mspan][1];
chan->raw[1] = ltc2664_mspan_lut[mspan][1];
chan->span = ltc2664_mspan_lut[mspan][0];
ret = fwnode_property_read_u32_array(child, "output-range-microvolt",
tmp, ARRAY_SIZE(tmp));
if (!ret && mspan == LTC2664_MSPAN_SOFTSPAN) {
chan->span = ltc2664_set_span(st, tmp[0] / 1000,
tmp[1] / 1000, reg);
if (span < 0)
return dev_err_probe(dev, span,
"Failed to set span\n");
}
ret = fwnode_property_read_u32_array(child, "output-range-microamp",
tmp, ARRAY_SIZE(tmp));
if (!ret) {
chan->span = ltc2664_set_span(st, 0, tmp[1] / 1000, reg);
if (span < 0)
return dev_err_probe(dev, span,
"Failed to set span\n");
}
}
return 0;
}
static int ltc2664_setup(struct ltc2664_state *st)
{
const struct ltc2664_chip_info *chip_info = st->chip_info;
struct gpio_desc *gpio;
int ret, i;
/* If we have a clr/reset pin, use that to reset the chip. */
gpio = devm_gpiod_get_optional(&st->spi->dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(gpio))
return dev_err_probe(&st->spi->dev, PTR_ERR(gpio),
"Failed to get reset gpio");
if (gpio) {
fsleep(1000);
gpiod_set_value_cansleep(gpio, 0);
}
/*
* Duplicate the default channel configuration as it can change during
* @ltc2664_channel_config()
*/
st->iio_channels = devm_kcalloc(&st->spi->dev,
chip_info->num_channels,
sizeof(struct iio_chan_spec),
GFP_KERNEL);
if (!st->iio_channels)
return -ENOMEM;
for (i = 0; i < chip_info->num_channels; i++) {
st->iio_channels[i] = ltc2664_channel_template;
st->iio_channels[i].type = chip_info->measurement_type;
st->iio_channels[i].channel = i;
}
ret = ltc2664_channel_config(st);
if (ret)
return ret;
return regmap_set_bits(st->regmap, LTC2664_CMD_CONFIG, LTC2664_REF_DISABLE);
}
static const struct regmap_config ltc2664_regmap_config = {
.reg_bits = 8,
.val_bits = 16,
.max_register = LTC2664_CMD_NO_OPERATION,
};
static const struct iio_info ltc2664_info = {
.write_raw = ltc2664_write_raw,
.read_raw = ltc2664_read_raw,
.read_avail = ltc2664_read_avail,
.debugfs_reg_access = ltc2664_reg_access,
};
static int ltc2664_probe(struct spi_device *spi)
{
static const char * const regulators[] = { "vcc", "iovcc", "v-neg" };
const struct ltc2664_chip_info *chip_info;
struct device *dev = &spi->dev;
struct iio_dev *indio_dev;
struct ltc2664_state *st;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
st->spi = spi;
chip_info = spi_get_device_match_data(spi);
if (!chip_info)
return -ENODEV;
st->chip_info = chip_info;
mutex_init(&st->lock);
st->regmap = devm_regmap_init_spi(spi, <c2664_regmap_config);
if (IS_ERR(st->regmap))
return dev_err_probe(dev, PTR_ERR(st->regmap),
"Failed to init regmap");
ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(regulators),
regulators);
if (ret)
return dev_err_probe(dev, ret, "Failed to enable regulators\n");
ret = devm_regulator_get_enable_read_voltage(dev, "ref");
if (ret < 0 && ret != -ENODEV)
return ret;
st->vref_mv = ret > 0 ? ret / 1000 : chip_info->internal_vref_mv;
ret = ltc2664_setup(st);
if (ret)
return ret;
indio_dev->name = chip_info->name;
indio_dev->info = <c2664_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = st->iio_channels;
indio_dev->num_channels = chip_info->num_channels;
return devm_iio_device_register(dev, indio_dev);
}
static const struct spi_device_id ltc2664_id[] = {
{ "ltc2664", (kernel_ulong_t)<c2664_chip },
{ "ltc2672", (kernel_ulong_t)<c2672_chip },
{ }
};
MODULE_DEVICE_TABLE(spi, ltc2664_id);
static const struct of_device_id ltc2664_of_id[] = {
{ .compatible = "adi,ltc2664", .data = <c2664_chip },
{ .compatible = "adi,ltc2672", .data = <c2672_chip },
{ }
};
MODULE_DEVICE_TABLE(of, ltc2664_of_id);
static struct spi_driver ltc2664_driver = {
.driver = {
.name = "ltc2664",
.of_match_table = ltc2664_of_id,
},
.probe = ltc2664_probe,
.id_table = ltc2664_id,
};
module_spi_driver(ltc2664_driver);
MODULE_AUTHOR("Michael Hennerich <[email protected]>");
MODULE_AUTHOR("Kim Seer Paller <[email protected]>");
MODULE_DESCRIPTION("Analog Devices LTC2664 and LTC2672 DAC");
MODULE_LICENSE("GPL");
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