// SPDX-License-Identifier: GPL-2.0+
/*
* lmp91000.c - Support for Texas Instruments digital potentiostats
*
* Copyright (C) 2016, 2018
* Author: Matt Ranostay <[email protected]>
*
* TODO: bias voltage + polarity control, and multiple chip support
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/mod_devicetable.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;
/* 64-bit data + 64-bit naturally aligned timestamp */
u32 buffer[4] __aligned(8);
};
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_nested(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;
unsigned int reg, val;
int i, ret;
ret = device_property_read_u32(dev, "ti,tia-gain-ohm", &val);
if (ret) {
if (!device_property_read_bool(dev, "ti,external-tia-resistor")) {
dev_err(dev, "no ti,tia-gain-ohm defined and external resistor not specified\n");
return ret;
}
val = 0;
}
ret = -EINVAL;
for (i = 0; i < ARRAY_SIZE(lmp91000_tia_gain); i++) {
if (lmp91000_tia_gain[i] == val) {
reg = i << LMP91000_REG_TIACN_GAIN_SHIFT;
ret = 0;
break;
}
}
if (ret) {
dev_err(dev, "invalid ti,tia-gain-ohm %d\n", val);
return ret;
}
ret = device_property_read_u32(dev, "ti,rload-ohm", &val);
if (ret) {
val = 100;
dev_info(dev, "no ti,rload-ohm defined, default to %d\n", val);
}
ret = -EINVAL;
for (i = 0; i < ARRAY_SIZE(lmp91000_rload); i++) {
if (lmp91000_rload[i] == val) {
reg |= i;
ret = 0;
break;
}
}
if (ret) {
dev_err(dev, "invalid ti,rload-ohm %d\n", val);
return ret;
}
regmap_write(data->regmap, LMP91000_REG_LOCK, 0);
regmap_write(data->regmap, LMP91000_REG_TIACN, reg);
regmap_write(data->regmap, LMP91000_REG_REFCN,
LMP91000_REG_REFCN_EXT_REF | LMP91000_REG_REFCN_50_ZERO);
regmap_write(data->regmap, LMP91000_REG_LOCK, 1);
return 0;
}
static int lmp91000_buffer_cb(const void *val, void *private)
{
struct iio_dev *indio_dev = private;
struct lmp91000_data *data = iio_priv(indio_dev);
data->buffer[data->chan_select] = *((int *)val);
complete_all(&data->completion);
return 0;
}
static int lmp91000_buffer_postenable(struct iio_dev *indio_dev)
{
struct lmp91000_data *data = iio_priv(indio_dev);
return iio_channel_start_all_cb(data->cb_buffer);
}
static int lmp91000_buffer_predisable(struct iio_dev *indio_dev)
{
struct lmp91000_data *data = iio_priv(indio_dev);
iio_channel_stop_all_cb(data->cb_buffer);
return 0;
}
static const struct iio_buffer_setup_ops lmp91000_buffer_setup_ops = {
.postenable = lmp91000_buffer_postenable,
.predisable = lmp91000_buffer_predisable,
};
static int lmp91000_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct lmp91000_data *data;
struct iio_dev *indio_dev;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
indio_dev->info = &lmp91000_info;
indio_dev->channels = lmp91000_channels;
indio_dev->num_channels = ARRAY_SIZE(lmp91000_channels);
indio_dev->name = LMP91000_DRV_NAME;
indio_dev->modes = INDIO_DIRECT_MODE;
i2c_set_clientdata(client, indio_dev);
data = iio_priv(indio_dev);
data->dev = dev;
data->regmap = devm_regmap_init_i2c(client, &lmp91000_regmap_config);
if (IS_ERR(data->regmap)) {
dev_err(dev, "regmap initialization failed.\n");
return PTR_ERR(data->regmap);
}
data->trig = devm_iio_trigger_alloc(dev, "%s-mux%d",
indio_dev->name,
iio_device_id(indio_dev));
if (!data->trig) {
dev_err(dev, "cannot allocate iio trigger.\n");
return -ENOMEM;
}
init_completion(&data->completion);
ret = lmp91000_read_config(data);
if (ret)
return ret;
ret = iio_trigger_set_immutable(iio_channel_cb_get_iio_dev(data->cb_buffer),
data->trig);
if (ret) {
dev_err(dev, "cannot set immutable trigger.\n");
return ret;
}
ret = iio_trigger_register(data->trig);
if (ret) {
dev_err(dev, "cannot register iio trigger.\n");
return ret;
}
ret = iio_triggered_buffer_setup(indio_dev, NULL,
&lmp91000_buffer_handler,
&lmp91000_buffer_setup_ops);
if (ret)
goto error_unreg_trigger;
data->cb_buffer = iio_channel_get_all_cb(dev, &lmp91000_buffer_cb,
indio_dev);
if (IS_ERR(data->cb_buffer)) {
if (PTR_ERR(data->cb_buffer) == -ENODEV)
ret = -EPROBE_DEFER;
else
ret = PTR_ERR(data->cb_buffer);
goto error_unreg_buffer;
}
data->adc_chan = iio_channel_cb_get_channels(data->cb_buffer);
ret = iio_device_register(indio_dev);
if (ret)
goto error_unreg_cb_buffer;
return 0;
error_unreg_cb_buffer:
iio_channel_release_all_cb(data->cb_buffer);
error_unreg_buffer:
iio_triggered_buffer_cleanup(indio_dev);
error_unreg_trigger:
iio_trigger_unregister(data->trig);
return ret;
}
static void lmp91000_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct lmp91000_data *data = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_channel_stop_all_cb(data->cb_buffer);
iio_channel_release_all_cb(data->cb_buffer);
iio_triggered_buffer_cleanup(indio_dev);
iio_trigger_unregister(data->trig);
}
static const struct of_device_id lmp91000_of_match[] = {
{ .compatible = "ti,lmp91000", },
{ .compatible = "ti,lmp91002", },
{ },
};
MODULE_DEVICE_TABLE(of, lmp91000_of_match);
static const struct i2c_device_id lmp91000_id[] = {
{ "lmp91000" },
{ "lmp91002" },
{}
};
MODULE_DEVICE_TABLE(i2c, lmp91000_id);
static struct i2c_driver lmp91000_driver = {
.driver = {
.name = LMP91000_DRV_NAME,
.of_match_table = lmp91000_of_match,
},
.probe = lmp91000_probe,
.remove = lmp91000_remove,
.id_table = lmp91000_id,
};
module_i2c_driver(lmp91000_driver);
MODULE_AUTHOR("Matt Ranostay <[email protected]>");
MODULE_DESCRIPTION("LMP91000 digital potentiostat");
MODULE_LICENSE("GPL");
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