428 lines
10 KiB
C
428 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* lmp91000.c - Support for Texas Instruments digital potentiostats
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*
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* Copyright (C) 2016, 2018
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* Author: Matt Ranostay <matt.ranostay@konsulko.com>
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*
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* TODO: bias voltage + polarity control, and multiple chip support
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*/
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/delay.h>
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#include <linux/mod_devicetable.h>
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#include <linux/regmap.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/consumer.h>
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#include <linux/iio/trigger.h>
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#include <linux/iio/trigger_consumer.h>
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#include <linux/iio/triggered_buffer.h>
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#define LMP91000_REG_LOCK 0x01
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#define LMP91000_REG_TIACN 0x10
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#define LMP91000_REG_TIACN_GAIN_SHIFT 2
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#define LMP91000_REG_REFCN 0x11
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#define LMP91000_REG_REFCN_EXT_REF 0x20
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#define LMP91000_REG_REFCN_50_ZERO 0x80
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#define LMP91000_REG_MODECN 0x12
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#define LMP91000_REG_MODECN_3LEAD 0x03
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#define LMP91000_REG_MODECN_TEMP 0x07
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#define LMP91000_DRV_NAME "lmp91000"
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static const int lmp91000_tia_gain[] = { 0, 2750, 3500, 7000, 14000, 35000,
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120000, 350000 };
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static const int lmp91000_rload[] = { 10, 33, 50, 100 };
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#define LMP91000_TEMP_BASE -40
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static const u16 lmp91000_temp_lut[] = {
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1875, 1867, 1860, 1852, 1844, 1836, 1828, 1821, 1813, 1805,
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1797, 1789, 1782, 1774, 1766, 1758, 1750, 1742, 1734, 1727,
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1719, 1711, 1703, 1695, 1687, 1679, 1671, 1663, 1656, 1648,
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1640, 1632, 1624, 1616, 1608, 1600, 1592, 1584, 1576, 1568,
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1560, 1552, 1544, 1536, 1528, 1520, 1512, 1504, 1496, 1488,
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1480, 1472, 1464, 1456, 1448, 1440, 1432, 1424, 1415, 1407,
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1399, 1391, 1383, 1375, 1367, 1359, 1351, 1342, 1334, 1326,
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1318, 1310, 1302, 1293, 1285, 1277, 1269, 1261, 1253, 1244,
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1236, 1228, 1220, 1212, 1203, 1195, 1187, 1179, 1170, 1162,
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1154, 1146, 1137, 1129, 1121, 1112, 1104, 1096, 1087, 1079,
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1071, 1063, 1054, 1046, 1038, 1029, 1021, 1012, 1004, 996,
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987, 979, 971, 962, 954, 945, 937, 929, 920, 912,
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903, 895, 886, 878, 870, 861 };
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static const struct regmap_config lmp91000_regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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};
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struct lmp91000_data {
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struct regmap *regmap;
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struct device *dev;
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struct iio_trigger *trig;
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struct iio_cb_buffer *cb_buffer;
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struct iio_channel *adc_chan;
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struct completion completion;
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u8 chan_select;
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/* 64-bit data + 64-bit naturally aligned timestamp */
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u32 buffer[4] __aligned(8);
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};
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static const struct iio_chan_spec lmp91000_channels[] = {
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{ /* chemical channel mV */
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.type = IIO_VOLTAGE,
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.channel = 0,
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.address = LMP91000_REG_MODECN_3LEAD,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
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BIT(IIO_CHAN_INFO_OFFSET) |
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BIT(IIO_CHAN_INFO_SCALE),
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.scan_index = 0,
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.scan_type = {
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.sign = 's',
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.realbits = 32,
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.storagebits = 32,
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},
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},
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IIO_CHAN_SOFT_TIMESTAMP(1),
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{ /* temperature channel mV */
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.type = IIO_TEMP,
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.channel = 1,
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.address = LMP91000_REG_MODECN_TEMP,
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.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
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.scan_index = -1,
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},
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};
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static int lmp91000_read(struct lmp91000_data *data, int channel, int *val)
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{
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int state, ret;
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ret = regmap_read(data->regmap, LMP91000_REG_MODECN, &state);
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if (ret)
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return -EINVAL;
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ret = regmap_write(data->regmap, LMP91000_REG_MODECN, channel);
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if (ret)
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return -EINVAL;
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/* delay till first temperature reading is complete */
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if (state != channel && channel == LMP91000_REG_MODECN_TEMP)
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usleep_range(3000, 4000);
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data->chan_select = channel != LMP91000_REG_MODECN_3LEAD;
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iio_trigger_poll_chained(data->trig);
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ret = wait_for_completion_timeout(&data->completion, HZ);
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reinit_completion(&data->completion);
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if (!ret)
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return -ETIMEDOUT;
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*val = data->buffer[data->chan_select];
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return 0;
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}
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static irqreturn_t lmp91000_buffer_handler(int irq, void *private)
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{
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struct iio_poll_func *pf = private;
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struct iio_dev *indio_dev = pf->indio_dev;
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struct lmp91000_data *data = iio_priv(indio_dev);
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int ret, val;
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memset(data->buffer, 0, sizeof(data->buffer));
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ret = lmp91000_read(data, LMP91000_REG_MODECN_3LEAD, &val);
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if (!ret) {
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data->buffer[0] = val;
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iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
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iio_get_time_ns(indio_dev));
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}
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iio_trigger_notify_done(indio_dev->trig);
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return IRQ_HANDLED;
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}
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static int lmp91000_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct lmp91000_data *data = iio_priv(indio_dev);
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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case IIO_CHAN_INFO_PROCESSED: {
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int ret = iio_channel_start_all_cb(data->cb_buffer);
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if (ret)
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return ret;
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ret = lmp91000_read(data, chan->address, val);
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iio_channel_stop_all_cb(data->cb_buffer);
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if (ret)
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return ret;
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if (mask == IIO_CHAN_INFO_PROCESSED) {
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int tmp, i;
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ret = iio_convert_raw_to_processed(data->adc_chan,
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*val, &tmp, 1);
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if (ret)
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return ret;
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for (i = 0; i < ARRAY_SIZE(lmp91000_temp_lut); i++)
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if (lmp91000_temp_lut[i] < tmp)
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break;
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*val = (LMP91000_TEMP_BASE + i) * 1000;
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}
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return IIO_VAL_INT;
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}
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case IIO_CHAN_INFO_OFFSET:
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return iio_read_channel_offset(data->adc_chan, val, val2);
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case IIO_CHAN_INFO_SCALE:
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return iio_read_channel_scale(data->adc_chan, val, val2);
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}
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return -EINVAL;
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}
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static const struct iio_info lmp91000_info = {
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.read_raw = lmp91000_read_raw,
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};
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static int lmp91000_read_config(struct lmp91000_data *data)
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{
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struct device *dev = data->dev;
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unsigned int reg, val;
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int i, ret;
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ret = device_property_read_u32(dev, "ti,tia-gain-ohm", &val);
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if (ret) {
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if (!device_property_read_bool(dev, "ti,external-tia-resistor")) {
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dev_err(dev, "no ti,tia-gain-ohm defined and external resistor not specified\n");
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return ret;
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}
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val = 0;
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}
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ret = -EINVAL;
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for (i = 0; i < ARRAY_SIZE(lmp91000_tia_gain); i++) {
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if (lmp91000_tia_gain[i] == val) {
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reg = i << LMP91000_REG_TIACN_GAIN_SHIFT;
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ret = 0;
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break;
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}
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}
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if (ret) {
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dev_err(dev, "invalid ti,tia-gain-ohm %d\n", val);
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return ret;
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}
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ret = device_property_read_u32(dev, "ti,rload-ohm", &val);
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if (ret) {
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val = 100;
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dev_info(dev, "no ti,rload-ohm defined, default to %d\n", val);
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}
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ret = -EINVAL;
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for (i = 0; i < ARRAY_SIZE(lmp91000_rload); i++) {
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if (lmp91000_rload[i] == val) {
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reg |= i;
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ret = 0;
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break;
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}
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}
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if (ret) {
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dev_err(dev, "invalid ti,rload-ohm %d\n", val);
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return ret;
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}
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regmap_write(data->regmap, LMP91000_REG_LOCK, 0);
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regmap_write(data->regmap, LMP91000_REG_TIACN, reg);
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regmap_write(data->regmap, LMP91000_REG_REFCN,
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LMP91000_REG_REFCN_EXT_REF | LMP91000_REG_REFCN_50_ZERO);
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regmap_write(data->regmap, LMP91000_REG_LOCK, 1);
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return 0;
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}
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static int lmp91000_buffer_cb(const void *val, void *private)
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{
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struct iio_dev *indio_dev = private;
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struct lmp91000_data *data = iio_priv(indio_dev);
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data->buffer[data->chan_select] = *((int *)val);
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complete_all(&data->completion);
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return 0;
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}
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static int lmp91000_buffer_postenable(struct iio_dev *indio_dev)
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{
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struct lmp91000_data *data = iio_priv(indio_dev);
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return iio_channel_start_all_cb(data->cb_buffer);
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}
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static int lmp91000_buffer_predisable(struct iio_dev *indio_dev)
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{
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struct lmp91000_data *data = iio_priv(indio_dev);
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iio_channel_stop_all_cb(data->cb_buffer);
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return 0;
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}
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static const struct iio_buffer_setup_ops lmp91000_buffer_setup_ops = {
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.postenable = lmp91000_buffer_postenable,
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.predisable = lmp91000_buffer_predisable,
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};
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static int lmp91000_probe(struct i2c_client *client)
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{
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struct device *dev = &client->dev;
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struct lmp91000_data *data;
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struct iio_dev *indio_dev;
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int ret;
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indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
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if (!indio_dev)
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return -ENOMEM;
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indio_dev->info = &lmp91000_info;
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indio_dev->channels = lmp91000_channels;
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indio_dev->num_channels = ARRAY_SIZE(lmp91000_channels);
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indio_dev->name = LMP91000_DRV_NAME;
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indio_dev->modes = INDIO_DIRECT_MODE;
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i2c_set_clientdata(client, indio_dev);
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data = iio_priv(indio_dev);
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data->dev = dev;
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data->regmap = devm_regmap_init_i2c(client, &lmp91000_regmap_config);
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if (IS_ERR(data->regmap)) {
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dev_err(dev, "regmap initialization failed.\n");
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return PTR_ERR(data->regmap);
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}
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data->trig = devm_iio_trigger_alloc(dev, "%s-mux%d",
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indio_dev->name,
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iio_device_id(indio_dev));
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if (!data->trig) {
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dev_err(dev, "cannot allocate iio trigger.\n");
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return -ENOMEM;
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}
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init_completion(&data->completion);
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ret = lmp91000_read_config(data);
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if (ret)
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return ret;
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ret = iio_trigger_set_immutable(iio_channel_cb_get_iio_dev(data->cb_buffer),
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data->trig);
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if (ret) {
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dev_err(dev, "cannot set immutable trigger.\n");
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return ret;
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}
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ret = iio_trigger_register(data->trig);
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if (ret) {
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dev_err(dev, "cannot register iio trigger.\n");
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return ret;
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}
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ret = iio_triggered_buffer_setup(indio_dev, NULL,
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&lmp91000_buffer_handler,
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&lmp91000_buffer_setup_ops);
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if (ret)
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goto error_unreg_trigger;
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data->cb_buffer = iio_channel_get_all_cb(dev, &lmp91000_buffer_cb,
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indio_dev);
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if (IS_ERR(data->cb_buffer)) {
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if (PTR_ERR(data->cb_buffer) == -ENODEV)
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ret = -EPROBE_DEFER;
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else
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ret = PTR_ERR(data->cb_buffer);
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goto error_unreg_buffer;
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}
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data->adc_chan = iio_channel_cb_get_channels(data->cb_buffer);
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ret = iio_device_register(indio_dev);
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if (ret)
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goto error_unreg_cb_buffer;
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return 0;
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error_unreg_cb_buffer:
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iio_channel_release_all_cb(data->cb_buffer);
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error_unreg_buffer:
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iio_triggered_buffer_cleanup(indio_dev);
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error_unreg_trigger:
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iio_trigger_unregister(data->trig);
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return ret;
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}
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static void lmp91000_remove(struct i2c_client *client)
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{
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struct iio_dev *indio_dev = i2c_get_clientdata(client);
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struct lmp91000_data *data = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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iio_channel_stop_all_cb(data->cb_buffer);
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iio_channel_release_all_cb(data->cb_buffer);
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iio_triggered_buffer_cleanup(indio_dev);
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iio_trigger_unregister(data->trig);
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}
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static const struct of_device_id lmp91000_of_match[] = {
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{ .compatible = "ti,lmp91000", },
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{ .compatible = "ti,lmp91002", },
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{ },
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};
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MODULE_DEVICE_TABLE(of, lmp91000_of_match);
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static const struct i2c_device_id lmp91000_id[] = {
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{ "lmp91000", 0 },
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{ "lmp91002", 0 },
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{}
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};
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MODULE_DEVICE_TABLE(i2c, lmp91000_id);
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static struct i2c_driver lmp91000_driver = {
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.driver = {
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.name = LMP91000_DRV_NAME,
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.of_match_table = lmp91000_of_match,
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},
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.probe_new = lmp91000_probe,
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.remove = lmp91000_remove,
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.id_table = lmp91000_id,
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};
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module_i2c_driver(lmp91000_driver);
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MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
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MODULE_DESCRIPTION("LMP91000 digital potentiostat");
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MODULE_LICENSE("GPL");
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