On 03/07/16 22:59, Matt Ranostay wrote: > On Sun, Jul 3, 2016 at 6:41 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote: >> On 02/07/16 23:05, Matt Ranostay wrote: >>> Add support for the LMP91000 potentiostat which is used for chemical >>> sensing applications. >> Step one. I had to look up what a potentiostat was... So perhaps a brief >> idiots guide in the intro to the patch? >> :) >> >> This clearly raises some interesting questions... I'll put comments on that >> in the cover letter and more or less stick to reviewing code alone here. >> >> >>> >>> Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx> >>> --- >>> .../bindings/iio/potentiostat/lmp91000.txt | 28 ++ >>> drivers/iio/Kconfig | 1 + >>> drivers/iio/Makefile | 1 + >>> drivers/iio/potentiostat/Kconfig | 21 ++ >>> drivers/iio/potentiostat/Makefile | 6 + >>> drivers/iio/potentiostat/lmp91000.c | 303 +++++++++++++++++++++ >>> 6 files changed, 360 insertions(+) >>> create mode 100644 Documentation/devicetree/bindings/iio/potentiostat/lmp91000.txt >>> create mode 100644 drivers/iio/potentiostat/Kconfig >>> create mode 100644 drivers/iio/potentiostat/Makefile >>> create mode 100644 drivers/iio/potentiostat/lmp91000.c >>> >>> diff --git a/Documentation/devicetree/bindings/iio/potentiostat/lmp91000.txt b/Documentation/devicetree/bindings/iio/potentiostat/lmp91000.txt >>> new file mode 100644 >>> index 000000000000..636c548cedee >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/iio/potentiostat/lmp91000.txt >>> @@ -0,0 +1,28 @@ >>> +* Texas Instruments LMP91000 potentiostat >>> + >>> +http://www.ti.com/lit/ds/symlink/lmp91000.pdf >>> + >>> +Required properties: >>> + >>> + - compatible: should be "ti,lmp91000" >>> + - reg: the I2C address of the device >>> + - io-channels: the phandle and channel of the iio provider >>> + >>> +Optional properties: >>> + >>> + - ti,tia-gain-ohm: ohm value on the feedback loop for the transimpedance >>> + amplifier. Must be 0 (external resistor, default), 2750, 3500, 7000, 14000, >>> + 35000, 120000, or 350000 ohms. >> Better perhaps to have an explicit entry to say use the external resistor? >> If nothing else, it ought to be infinite resistance for that not 0. >> > > >> Also does it ever make sense to change this at runtime or is it a case of >> being matched to a particular probe? > > I mean it doesn't in theory damage anything but probably an un-needed > runtime configuration complexity. > >>> + >>> + - ti,rload-ohm: ohm value of the internal resistor load applied to the gas >>> + sensor. Must be 10, 33, 50, or 100 (default) ohms. >> Again, make sense to ever change at runtime? Guessing there is still a best >> value for a given probe even if sometimes it might want 'tweaking'. >> >> No idea - never even seen one of these probes that I know of ;) > > Actually the load resistor value is documented in the sensor > datasheet, and never changes. > An incorrect value could in theory shorter the life of the sensor. Cool. Perhaps expand the description to make this clear? > >>> + >>> +Example: >>> + >>> +lmp91000@48 { >>> + compatible = "ti,lmp91000"; >>> + reg = <0x48>; >>> + ti,tia-gain-ohm = <7500>; >>> + ti,rload = <100>; >>> + io-channels = <&adc1x1s 0>; >>> +}; >>> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig >>> index 6743b18194fb..a31a8cf2c330 100644 >>> --- a/drivers/iio/Kconfig >>> +++ b/drivers/iio/Kconfig >>> @@ -87,6 +87,7 @@ if IIO_TRIGGER >>> source "drivers/iio/trigger/Kconfig" >>> endif #IIO_TRIGGER >>> source "drivers/iio/potentiometer/Kconfig" >>> +source "drivers/iio/potentiostat/Kconfig" >>> source "drivers/iio/pressure/Kconfig" >>> source "drivers/iio/proximity/Kconfig" >>> source "drivers/iio/temperature/Kconfig" >>> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile >>> index 87e4c4369e2f..2b6e2762a886 100644 >>> --- a/drivers/iio/Makefile >>> +++ b/drivers/iio/Makefile >>> @@ -29,6 +29,7 @@ obj-y += light/ >>> obj-y += magnetometer/ >>> obj-y += orientation/ >>> obj-y += potentiometer/ >>> +obj-y += potentiostat/ >> I wonder if grouping analog front ends in at subdirectory above this >> might make sense? Feels like we may get some more. We already have >> 'amplifiers' that could be moved into that directory as well. >> >> Or for now we could just have both this and amplifiers in an >> 'Analog front ends' directory and break them up into their own directories >> if we get too many to handle in a single dir in the future? I don't really >> mind but would like this an amplifiers grouped together in some way. >> >>> obj-y += pressure/ >>> obj-y += proximity/ >>> obj-y += temperature/ >>> diff --git a/drivers/iio/potentiostat/Kconfig b/drivers/iio/potentiostat/Kconfig >>> new file mode 100644 >>> index 000000000000..591682c05ae9 >>> --- /dev/null >>> +++ b/drivers/iio/potentiostat/Kconfig >>> @@ -0,0 +1,21 @@ >>> +# >>> +# Potentiostat drivers >>> +# >>> +# When adding new entries keep the list in alphabetical order >>> + >>> +menu "Digital potentiostats" >>> + >>> +config LMP91000 >>> + tristate "Texas Instruments LMP91000 potentiostat driver" >>> + depends on I2C >>> + select REGMAP_I2C >>> + select IIO_BUFFER >>> + select IIO_TRIGGERED_BUFFER >>> + help >>> + Say yes here to build support for the Texas Instruments >>> + LMP91000 digital potentiostat chip. >>> + >>> + To compile this driver as a module, choose M here: the >>> + module will be called lmp91000 >>> + >>> +endmenu >>> diff --git a/drivers/iio/potentiostat/Makefile b/drivers/iio/potentiostat/Makefile >>> new file mode 100644 >>> index 000000000000..64d315ef4449 >>> --- /dev/null >>> +++ b/drivers/iio/potentiostat/Makefile >>> @@ -0,0 +1,6 @@ >>> +# >>> +# Makefile for industrial I/O potentiostat drivers >>> +# >>> + >>> +# When adding new entries keep the list in alphabetical order >>> +obj-$(CONFIG_LMP91000) += lmp91000.o >>> diff --git a/drivers/iio/potentiostat/lmp91000.c b/drivers/iio/potentiostat/lmp91000.c >>> new file mode 100644 >>> index 000000000000..fe90172eac28 >>> --- /dev/null >>> +++ b/drivers/iio/potentiostat/lmp91000.c >>> @@ -0,0 +1,303 @@ >>> +/* >>> + * lmp91000.c - Support for Texas Instruments digital potentiostats >>> + * >>> + * Copyright (C) 2016 Matt Ranostay <mranostay@xxxxxxxxx> >>> + * >>> + * 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_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 }; >>> + >>> +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_channel *vout_chan; >>> + >>> + u8 buffer[16]; /* 32-bit data + 32-bit padding + 64-bit timestamp */ >>> +}; >>> + >>> +static const struct iio_chan_spec lmp91000_channels[] = { >>> + { /* chemical channel mV */ >>> + .type = IIO_VOLTAGE, >>> + .channel = 0, >>> + .indexed = 1, >>> + .address = LMP91000_REG_MODECN_3LEAD, >>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), >>> + .scan_index = 0, >>> + .scan_type = { >>> + .sign = 's', >>> + .realbits = 32, >>> + .storagebits = 32, >>> + }, >>> + }, >>> + IIO_CHAN_SOFT_TIMESTAMP(1), >>> + { /* temperature channel mV */ >>> + .type = IIO_VOLTAGE, >>> + .channel = 1, >>> + .indexed = 1, >>> + .address = LMP91000_REG_MODECN_TEMP, >>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), >>> + .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); >>> + >>> + ret = iio_read_channel_raw(data->vout_chan, val); >>> + if (ret < 0) >>> + return ret; >>> + >>> + return 0; >>> +} >>> + >>> +static irqreturn_t lmp91000_trigger_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; >>> + >>> + ret = lmp91000_read(data, LMP91000_REG_MODECN_3LEAD, &val); >>> + if (!ret) { >>> + *((int *) data->buffer) = val; >>> + iio_push_to_buffers_with_timestamp(indio_dev, data->buffer, >>> + iio_get_time_ns()); >>> + } >>> + >>> + 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); >>> + int ret; >>> + >>> + if (mask != IIO_CHAN_INFO_RAW) >>> + return -EINVAL; >>> + >>> + if (iio_device_claim_direct_mode(indio_dev)) >>> + return -EBUSY; >>> + >>> + ret = lmp91000_read(data, chan->address, val); >>> + if (!ret) >>> + ret = IIO_VAL_INT; >>> + >>> + iio_device_release_direct_mode(indio_dev); >>> + >>> + return ret; >>> +} >>> + >>> +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; >>> + int i, val1, val2, ret; >>> + >>> + ret = of_property_read_u32(np, "ti,tia-gain-ohm", &val1); >>> + if (ret) { >>> + val1 = 0; >>> + dev_info(dev, "no ti,tia-gain-ohm defined, default to external\n"); >>> + } >>> + >>> + ret = of_property_read_u32(np, "ti,rload-ohm", &val2); >>> + if (ret) { >>> + val2 = 100; >>> + dev_info(dev, "no ti,rload-ohm defined, default to %d\n", val2); >>> + } >>> + >> I'd reorder this to have the property followed by it's use together. >> Not terribly keen on variables with names as generic as val1 and val2 either. >>> + ret = -EINVAL; >>> + for (i = 0; i < ARRAY_SIZE(lmp91000_tia_gain); i++) { >>> + if (lmp91000_tia_gain[i] == val1) { >>> + val1 = i; >>> + ret = 0; >>> + break; >>> + } >>> + } >>> + >>> + if (ret) { >>> + dev_err(dev, "invalid ti,tia-gain-ohm %d", val1); >>> + return ret; >>> + } >>> + >>> + ret = -EINVAL; >>> + for (i = 0; i < ARRAY_SIZE(lmp91000_rload); i++) { >>> + if (lmp91000_rload[i] == val2) { >>> + val2 = i; >>> + ret = 0; >>> + break; >>> + } >>> + } >>> + >>> + if (ret) { >>> + dev_err(dev, "invalid ti,rload-ohm %d", val2); >>> + return ret; >>> + } >>> + >>> + regmap_write(data->regmap, LMP91000_REG_LOCK, 0); >> Error handling? >>> + regmap_write(data->regmap, LMP91000_REG_TIACN, >>> + (val1 << LMP91000_REG_TIACN_GAIN_SHIFT) | val2); >>> + 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_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; >>> + struct iio_channel *vout_chan; >>> + int ret; >>> + >>> + vout_chan = iio_channel_get(dev, NULL); >>> + if (IS_ERR(vout_chan)) >>> + return -EPROBE_DEFER; >>> + >>> + 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->vout_chan = vout_chan; >>> + 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); >>> + } >>> + >>> + ret = lmp91000_read_config(data); >>> + if (ret) >>> + return ret; >>> + >>> + ret = iio_triggered_buffer_setup(indio_dev, NULL, >>> + lmp91000_trigger_handler, NULL); >>> + if (ret) >>> + return ret; >>> + >>> + ret = iio_device_register(indio_dev); >>> + if (ret) >>> + goto error_unreg_buffer; >>> + >>> + return 0; >>> + >>> +error_unreg_buffer: >>> + iio_triggered_buffer_cleanup(indio_dev); >>> + >>> + 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_triggered_buffer_cleanup(indio_dev); >>> + iio_channel_release(data->vout_chan); >>> + >>> + 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@xxxxxxxxx>"); >>> +MODULE_DESCRIPTION("LMP91000 digital potentiostat"); >>> +MODULE_LICENSE("GPL"); >>> >> -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
