--- /dev/null
+/*
+ * lmp91000.c - Support for Texas Instruments digital potentiostats
+ *
+ * Copyright (C) 2016 Matt Ranostay <mranostay@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * 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 = {
+ .driver_module = THIS_MODULE,
+ .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 ret;
+ }
+ }
+
+ 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 = of_property_read_u32(np, "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 const struct iio_trigger_ops lmp91000_trigger_ops = {
+ .owner = THIS_MODULE,
+};
+
+
+static int lmp91000_buffer_preenable(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 = {
+ .preenable = lmp91000_buffer_preenable,
+ .postenable = iio_triggered_buffer_postenable,
+ .predisable = lmp91000_buffer_predisable,
+};
+
+static int lmp91000_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ 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(data->dev, "%s-mux%d",
+ indio_dev->name, indio_dev->id);
+ if (!data->trig) {
+ dev_err(dev, "cannot allocate iio trigger.\n");
+ return -ENOMEM;
+ }
+
+ data->trig->ops = &lmp91000_trigger_ops;
+ data->trig->dev.parent = dev;
+ 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 int 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);
+
+ return 0;
+}
+
+static const struct of_device_id lmp91000_of_match[] = {
+ { .compatible = "ti,lmp91000", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, lmp91000_of_match);
+
+static const struct i2c_device_id lmp91000_id[] = {
+ { "lmp91000", 0 },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, lmp91000_id);
+
+static struct i2c_driver lmp91000_driver = {
+ .driver = {
+ .name = LMP91000_DRV_NAME,
+ .of_match_table = of_match_ptr(lmp91000_of_match),
+ },
+ .probe = lmp91000_probe,
+ .remove = lmp91000_remove,
+ .id_table = lmp91000_id,
+};
+module_i2c_driver(lmp91000_driver);
+
+MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
+MODULE_DESCRIPTION("LMP91000 digital potentiostat");
+MODULE_LICENSE("GPL");
projects / karo-tx-linux.git / commitdiff