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// SPDX-License-Identifier: GPL-2.0+
/*
* lmp91000.c - Support for Texas Instruments digital potentiostats
*
* Copyright (C) 2016, 2018
* Author: Matt Ranostay <matt.ranostay@konsulko.com>
*
* TODO: bias voltage + polarity control, and multiple chip support
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/consumer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#define LMP91000_REG_LOCK 0x01
#define LMP91000_REG_TIACN 0x10
#define LMP91000_REG_TIACN_GAIN_SHIFT 2
#define LMP91000_REG_REFCN 0x11
#define LMP91000_REG_REFCN_EXT_REF 0x20
#define LMP91000_REG_REFCN_50_ZERO 0x80
#define LMP91000_REG_MODECN 0x12
#define LMP91000_REG_MODECN_3LEAD 0x03
#define LMP91000_REG_MODECN_TEMP 0x07
#define LMP91000_DRV_NAME "lmp91000"
static const int lmp91000_tia_gain[] = { 0, 2750, 3500, 7000, 14000, 35000,
120000, 350000 };
static const int lmp91000_rload[] = { 10, 33, 50, 100 };
#define LMP91000_TEMP_BASE -40
static const u16 lmp91000_temp_lut[] = {
1875, 1867, 1860, 1852, 1844, 1836, 1828, 1821, 1813, 1805,
1797, 1789, 1782, 1774, 1766, 1758, 1750, 1742, 1734, 1727,
1719, 1711, 1703, 1695, 1687, 1679, 1671, 1663, 1656, 1648,
1640, 1632, 1624, 1616, 1608, 1600, 1592, 1584, 1576, 1568,
1560, 1552, 1544, 1536, 1528, 1520, 1512, 1504, 1496, 1488,
1480, 1472, 1464, 1456, 1448, 1440, 1432, 1424, 1415, 1407,
1399, 1391, 1383, 1375, 1367, 1359, 1351, 1342, 1334, 1326,
1318, 1310, 1302, 1293, 1285, 1277, 1269, 1261, 1253, 1244,
1236, 1228, 1220, 1212, 1203, 1195, 1187, 1179, 1170, 1162,
1154, 1146, 1137, 1129, 1121, 1112, 1104, 1096, 1087, 1079,
1071, 1063, 1054, 1046, 1038, 1029, 1021, 1012, 1004, 996,
987, 979, 971, 962, 954, 945, 937, 929, 920, 912,
903, 895, 886, 878, 870, 861 };
static const struct regmap_config lmp91000_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
};
struct lmp91000_data {
struct regmap *regmap;
struct device *dev;
struct iio_trigger *trig;
struct iio_cb_buffer *cb_buffer;
struct iio_channel *adc_chan;
struct completion completion;
u8 chan_select;
u32 buffer[4]; /* 64-bit data + 64-bit timestamp */
};
static const struct iio_chan_spec lmp91000_channels[] = {
{ /* chemical channel mV */
.type = IIO_VOLTAGE,
.channel = 0,
.address = LMP91000_REG_MODECN_3LEAD,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_OFFSET) |
BIT(IIO_CHAN_INFO_SCALE),
.scan_index = 0,
.scan_type = {
.sign = 's',
.realbits = 32,
.storagebits = 32,
},
},
IIO_CHAN_SOFT_TIMESTAMP(1),
{ /* temperature channel mV */
.type = IIO_TEMP,
.channel = 1,
.address = LMP91000_REG_MODECN_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
.scan_index = -1,
},
};
static int lmp91000_read(struct lmp91000_data *data, int channel, int *val)
{
int state, ret;
ret = regmap_read(data->regmap, LMP91000_REG_MODECN, &state);
if (ret)
return -EINVAL;
ret = regmap_write(data->regmap, LMP91000_REG_MODECN, channel);
if (ret)
return -EINVAL;
/* delay till first temperature reading is complete */
if ((state != channel) && (channel == LMP91000_REG_MODECN_TEMP))
usleep_range(3000, 4000);
data->chan_select = channel != LMP91000_REG_MODECN_3LEAD;
iio_trigger_poll_chained(data->trig);
ret = wait_for_completion_timeout(&data->completion, HZ);
reinit_completion(&data->completion);
if (!ret)
return -ETIMEDOUT;
*val = data->buffer[data->chan_select];
return 0;
}
static irqreturn_t lmp91000_buffer_handler(int irq, void *private)
{
struct iio_poll_func *pf = private;
struct iio_dev *indio_dev = pf->indio_dev;
struct lmp91000_data *data = iio_priv(indio_dev);
int ret, val;
memset(data->buffer, 0, sizeof(data->buffer));
ret = lmp91000_read(data, LMP91000_REG_MODECN_3LEAD, &val);
if (!ret) {
data->buffer[0] = val;
iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
iio_get_time_ns(indio_dev));
}
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int lmp91000_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct lmp91000_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
case IIO_CHAN_INFO_PROCESSED: {
int ret = iio_channel_start_all_cb(data->cb_buffer);
if (ret)
return ret;
ret = lmp91000_read(data, chan->address, val);
iio_channel_stop_all_cb(data->cb_buffer);
if (ret)
return ret;
if (mask == IIO_CHAN_INFO_PROCESSED) {
int tmp, i;
ret = iio_convert_raw_to_processed(data->adc_chan,
*val, &tmp, 1);
if (ret)
return ret;
for (i = 0; i < ARRAY_SIZE(lmp91000_temp_lut); i++)
if (lmp91000_temp_lut[i] < tmp)
break;
*val = (LMP91000_TEMP_BASE + i) * 1000;
}
return IIO_VAL_INT;
}
case IIO_CHAN_INFO_OFFSET:
return iio_read_channel_offset(data->adc_chan, val, val2);
case IIO_CHAN_INFO_SCALE:
return iio_read_channel_scale(data->adc_chan, val, val2);
}
return -EINVAL;
}
static const struct iio_info lmp91000_info = {
.read_raw = lmp91000_read_raw,
};
static int lmp91000_read_config(struct lmp91000_data *data)
{
struct device *dev = data->dev;
struct device_node *np = dev->of_node;
unsigned int reg, val;
int i, ret;
ret = of_property_read_u32(np, "ti,tia-gain-ohm", &val);
if (ret) {
if (of_property_read_bool(np, "ti,external-tia-resistor"))
val = 0;
else {
dev_err(dev, "no ti,tia-gain-ohm defined");
return <
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