drivers/iio/chemical/atlas-ph-sensor.c - kernel/quantenna - Git at Google

 /*
  * atlas-ph-sensor.c - Support for Atlas Scientific OEM pH-SM sensor
  *
  * Copyright (C) 2015 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.
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
 #include <linux/mutex.h>
 #include <linux/err.h>
 #include <linux/irq.h>
 #include <linux/irq_work.h>
 #include <linux/gpio.h>
 #include <linux/i2c.h>
 #include <linux/regmap.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/trigger.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>
 #include <linux/pm_runtime.h>

 #define ATLAS_REGMAP_NAME	"atlas_ph_regmap"
 #define ATLAS_DRV_NAME		"atlas_ph"

 #define ATLAS_REG_DEV_TYPE		0x00
 #define ATLAS_REG_DEV_VERSION		0x01

 #define ATLAS_REG_INT_CONTROL		0x04
 #define ATLAS_REG_INT_CONTROL_EN	BIT(3)

 #define ATLAS_REG_PWR_CONTROL		0x06

 #define ATLAS_REG_CALIB_STATUS		0x0d
 #define ATLAS_REG_CALIB_STATUS_MASK	0x07
 #define ATLAS_REG_CALIB_STATUS_LOW	BIT(0)
 #define ATLAS_REG_CALIB_STATUS_MID	BIT(1)
 #define ATLAS_REG_CALIB_STATUS_HIGH	BIT(2)

 #define ATLAS_REG_TEMP_DATA		0x0e
 #define ATLAS_REG_PH_DATA		0x16

 #define ATLAS_PH_INT_TIME_IN_US		450000

 struct atlas_data {
 	struct i2c_client *client;
 	struct iio_trigger *trig;
 	struct regmap *regmap;
 	struct irq_work work;

 	__be32 buffer[4]; /* 32-bit pH data + 32-bit pad + 64-bit timestamp */
 };

 static const struct regmap_range atlas_volatile_ranges[] = {
 	regmap_reg_range(ATLAS_REG_INT_CONTROL, ATLAS_REG_INT_CONTROL),
 	regmap_reg_range(ATLAS_REG_PH_DATA, ATLAS_REG_PH_DATA + 4),
 };

 static const struct regmap_access_table atlas_volatile_table = {
 	.yes_ranges	= atlas_volatile_ranges,
 	.n_yes_ranges	= ARRAY_SIZE(atlas_volatile_ranges),
 };

 static const struct regmap_config atlas_regmap_config = {
 	.name = ATLAS_REGMAP_NAME,

 	.reg_bits = 8,
 	.val_bits = 8,

 	.volatile_table = &atlas_volatile_table,
 	.max_register = ATLAS_REG_PH_DATA + 4,
 	.cache_type = REGCACHE_RBTREE,
 };

 static const struct iio_chan_spec atlas_channels[] = {
 	{
 		.type = IIO_PH,
 		.info_mask_separate =
 			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 		.scan_index = 0,
 		.scan_type = {
 			.sign = 'u',
 			.realbits = 32,
 			.storagebits = 32,
 			.endianness = IIO_BE,
 		},
 	},
 	IIO_CHAN_SOFT_TIMESTAMP(1),
 	{
 		.type = IIO_TEMP,
 		.address = ATLAS_REG_TEMP_DATA,
 		.info_mask_separate =
 			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 		.output = 1,
 		.scan_index = -1
 	},
 };

 static int atlas_set_powermode(struct atlas_data *data, int on)
 {
 	return regmap_write(data->regmap, ATLAS_REG_PWR_CONTROL, on);
 }

 static int atlas_set_interrupt(struct atlas_data *data, bool state)
 {
 	return regmap_update_bits(data->regmap, ATLAS_REG_INT_CONTROL,
 				  ATLAS_REG_INT_CONTROL_EN,
 				  state ? ATLAS_REG_INT_CONTROL_EN : 0);
 }

 static int atlas_buffer_postenable(struct iio_dev *indio_dev)
 {
 	struct atlas_data *data = iio_priv(indio_dev);
 	int ret;

 	ret = iio_triggered_buffer_postenable(indio_dev);
 	if (ret)
 		return ret;

 	ret = pm_runtime_get_sync(&data->client->dev);
 	if (ret < 0) {
 		pm_runtime_put_noidle(&data->client->dev);
 		return ret;
 	}

 	return atlas_set_interrupt(data, true);
 }

 static int atlas_buffer_predisable(struct iio_dev *indio_dev)
 {
 	struct atlas_data *data = iio_priv(indio_dev);
 	int ret;

 	ret = iio_triggered_buffer_predisable(indio_dev);
 	if (ret)
 		return ret;

 	ret = atlas_set_interrupt(data, false);
 	if (ret)
 		return ret;

 	pm_runtime_mark_last_busy(&data->client->dev);
 	return pm_runtime_put_autosuspend(&data->client->dev);
 }

 static const struct iio_trigger_ops atlas_interrupt_trigger_ops = {
 	.owner = THIS_MODULE,
 };

 static const struct iio_buffer_setup_ops atlas_buffer_setup_ops = {
 	.postenable = atlas_buffer_postenable,
 	.predisable = atlas_buffer_predisable,
 };

 static void atlas_work_handler(struct irq_work *work)
 {
 	struct atlas_data *data = container_of(work, struct atlas_data, work);

 	iio_trigger_poll(data->trig);
 }

 static irqreturn_t atlas_trigger_handler(int irq, void *private)
 {
 	struct iio_poll_func *pf = private;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct atlas_data *data = iio_priv(indio_dev);
 	int ret;

 	ret = regmap_bulk_read(data->regmap, ATLAS_REG_PH_DATA,
 			      (u8 *) &data->buffer, sizeof(data->buffer[0]));

 	if (!ret)
 		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 irqreturn_t atlas_interrupt_handler(int irq, void *private)
 {
 	struct iio_dev *indio_dev = private;
 	struct atlas_data *data = iio_priv(indio_dev);

 	irq_work_queue(&data->work);

 	return IRQ_HANDLED;
 }

 static int atlas_read_ph_measurement(struct atlas_data *data, __be32 *val)
 {
 	struct device *dev = &data->client->dev;
 	int suspended = pm_runtime_suspended(dev);
 	int ret;

 	ret = pm_runtime_get_sync(dev);
 	if (ret < 0) {
 		pm_runtime_put_noidle(dev);
 		return ret;
 	}

 	if (suspended)
 		usleep_range(ATLAS_PH_INT_TIME_IN_US,
 			     ATLAS_PH_INT_TIME_IN_US + 100000);

 	ret = regmap_bulk_read(data->regmap, ATLAS_REG_PH_DATA,
 			      (u8 *) val, sizeof(*val));

 	pm_runtime_mark_last_busy(dev);
 	pm_runtime_put_autosuspend(dev);

 	return ret;
 }

 static int atlas_read_raw(struct iio_dev *indio_dev,
 			  struct iio_chan_spec const *chan,
 			  int *val, int *val2, long mask)
 {
 	struct atlas_data *data = iio_priv(indio_dev);

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW: {
 		int ret;
 		__be32 reg;

 		switch (chan->type) {
 		case IIO_TEMP:
 			ret = regmap_bulk_read(data->regmap, chan->address,
 					      (u8 *) &reg, sizeof(reg));
 			break;
 		case IIO_PH:
 			mutex_lock(&indio_dev->mlock);

 			if (iio_buffer_enabled(indio_dev))
 				ret = -EBUSY;
 			else
 				ret = atlas_read_ph_measurement(data, &reg);

 			mutex_unlock(&indio_dev->mlock);
 			break;
 		default:
 			ret = -EINVAL;
 		}

 		if (!ret) {
 			*val = be32_to_cpu(reg);
 			ret = IIO_VAL_INT;
 		}
 		return ret;
 	}
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->type) {
 		case IIO_TEMP:
 			*val = 1; /* 0.01 */
 			*val2 = 100;
 			break;
 		case IIO_PH:
 			*val = 1; /* 0.001 */
 			*val2 = 1000;
 			break;
 		default:
 			return -EINVAL;
 		}
 		return IIO_VAL_FRACTIONAL;
 	}

 	return -EINVAL;
 }

 static int atlas_write_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int val, int val2, long mask)
 {
 	struct atlas_data *data = iio_priv(indio_dev);
 	__be32 reg = cpu_to_be32(val);

 	if (val2 != 0 || val < 0 || val > 20000)
 		return -EINVAL;

 	if (mask != IIO_CHAN_INFO_RAW || chan->type != IIO_TEMP)
 		return -EINVAL;

 	return regmap_bulk_write(data->regmap, chan->address,
 				 &reg, sizeof(reg));
 }

 static const struct iio_info atlas_info = {
 	.driver_module = THIS_MODULE,
 	.read_raw = atlas_read_raw,
 	.write_raw = atlas_write_raw,
 };

 static int atlas_check_calibration(struct atlas_data *data)
 {
 	struct device *dev = &data->client->dev;
 	int ret;
 	unsigned int val;

 	ret = regmap_read(data->regmap, ATLAS_REG_CALIB_STATUS, &val);
 	if (ret)
 		return ret;

 	if (!(val & ATLAS_REG_CALIB_STATUS_MASK)) {
 		dev_warn(dev, "device has not been calibrated\n");
 		return 0;
 	}

 	if (!(val & ATLAS_REG_CALIB_STATUS_LOW))
 		dev_warn(dev, "device missing low point calibration\n");

 	if (!(val & ATLAS_REG_CALIB_STATUS_MID))
 		dev_warn(dev, "device missing mid point calibration\n");

 	if (!(val & ATLAS_REG_CALIB_STATUS_HIGH))
 		dev_warn(dev, "device missing high point calibration\n");

 	return 0;
 };

 static int atlas_probe(struct i2c_client *client,
 		       const struct i2c_device_id *id)
 {
 	struct atlas_data *data;
 	struct iio_trigger *trig;
 	struct iio_dev *indio_dev;
 	int ret;

 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (!indio_dev)
 		return -ENOMEM;

 	indio_dev->info = &atlas_info;
 	indio_dev->name = ATLAS_DRV_NAME;
 	indio_dev->channels = atlas_channels;
 	indio_dev->num_channels = ARRAY_SIZE(atlas_channels);
 	indio_dev->modes = INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE;
 	indio_dev->dev.parent = &client->dev;

 	trig = devm_iio_trigger_alloc(&client->dev, "%s-dev%d",
 				      indio_dev->name, indio_dev->id);

 	if (!trig)
 		return -ENOMEM;

 	data = iio_priv(indio_dev);
 	data->client = client;
 	data->trig = trig;
 	trig->dev.parent = indio_dev->dev.parent;
 	trig->ops = &atlas_interrupt_trigger_ops;
 	iio_trigger_set_drvdata(trig, indio_dev);

 	i2c_set_clientdata(client, indio_dev);

 	data->regmap = devm_regmap_init_i2c(client, &atlas_regmap_config);
 	if (IS_ERR(data->regmap)) {
 		dev_err(&client->dev, "regmap initialization failed\n");
 		return PTR_ERR(data->regmap);
 	}

 	ret = pm_runtime_set_active(&client->dev);
 	if (ret)
 		return ret;

 	if (client->irq <= 0) {
 		dev_err(&client->dev, "no valid irq defined\n");
 		return -EINVAL;
 	}

 	ret = atlas_check_calibration(data);
 	if (ret)
 		return ret;

 	ret = iio_trigger_register(trig);
 	if (ret) {
 		dev_err(&client->dev, "failed to register trigger\n");
 		return ret;
 	}

 	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
 		&atlas_trigger_handler, &atlas_buffer_setup_ops);
 	if (ret) {
 		dev_err(&client->dev, "cannot setup iio trigger\n");
 		goto unregister_trigger;
 	}

 	init_irq_work(&data->work, atlas_work_handler);

 	/* interrupt pin toggles on new conversion */
 	ret = devm_request_threaded_irq(&client->dev, client->irq,
 					NULL, atlas_interrupt_handler,
 					IRQF_TRIGGER_RISING |
 					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 					"atlas_irq",
 					indio_dev);
 	if (ret) {
 		dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
 		goto unregister_buffer;
 	}

 	ret = atlas_set_powermode(data, 1);
 	if (ret) {
 		dev_err(&client->dev, "cannot power device on");
 		goto unregister_buffer;
 	}

 	pm_runtime_enable(&client->dev);
 	pm_runtime_set_autosuspend_delay(&client->dev, 2500);
 	pm_runtime_use_autosuspend(&client->dev);

 	ret = iio_device_register(indio_dev);
 	if (ret) {
 		dev_err(&client->dev, "unable to register device\n");
 		goto unregister_pm;
 	}

 	return 0;

 unregister_pm:
 	pm_runtime_disable(&client->dev);
 	atlas_set_powermode(data, 0);

 unregister_buffer:
 	iio_triggered_buffer_cleanup(indio_dev);

 unregister_trigger:
 	iio_trigger_unregister(data->trig);

 	return ret;
 }

 static int atlas_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
 	struct atlas_data *data = iio_priv(indio_dev);

 	iio_device_unregister(indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);
 	iio_trigger_unregister(data->trig);

 	pm_runtime_disable(&client->dev);
 	pm_runtime_set_suspended(&client->dev);
 	pm_runtime_put_noidle(&client->dev);

 	return atlas_set_powermode(data, 0);
 }

 #ifdef CONFIG_PM
 static int atlas_runtime_suspend(struct device *dev)
 {
 	struct atlas_data *data =
 		     iio_priv(i2c_get_clientdata(to_i2c_client(dev)));

 	return atlas_set_powermode(data, 0);
 }

 static int atlas_runtime_resume(struct device *dev)
 {
 	struct atlas_data *data =
 		     iio_priv(i2c_get_clientdata(to_i2c_client(dev)));

 	return atlas_set_powermode(data, 1);
 }
 #endif

 static const struct dev_pm_ops atlas_pm_ops = {
 	SET_RUNTIME_PM_OPS(atlas_runtime_suspend,
 			   atlas_runtime_resume, NULL)
 };

 static const struct i2c_device_id atlas_id[] = {
 	{ "atlas-ph-sm", 0 },
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, atlas_id);

 static const struct of_device_id atlas_dt_ids[] = {
 	{ .compatible = "atlas,ph-sm" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, atlas_dt_ids);

 static struct i2c_driver atlas_driver = {
 	.driver = {
 		.name	= ATLAS_DRV_NAME,
 		.of_match_table	= of_match_ptr(atlas_dt_ids),
 		.pm	= &atlas_pm_ops,
 	},
 	.probe		= atlas_probe,
 	.remove		= atlas_remove,
 	.id_table	= atlas_id,
 };
 module_i2c_driver(atlas_driver);

 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
 MODULE_DESCRIPTION("Atlas Scientific pH-SM sensor");
 MODULE_LICENSE("GPL");
	/*
	* atlas-ph-sensor.c - Support for Atlas Scientific OEM pH-SM sensor
	*
	* Copyright (C) 2015 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.
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/delay.h>
	#include <linux/mutex.h>
	#include <linux/err.h>
	#include <linux/irq.h>
	#include <linux/irq_work.h>
	#include <linux/gpio.h>
	#include <linux/i2c.h>
	#include <linux/regmap.h>
	#include <linux/iio/iio.h>
	#include <linux/iio/buffer.h>
	#include <linux/iio/trigger.h>
	#include <linux/iio/trigger_consumer.h>
	#include <linux/iio/triggered_buffer.h>
	#include <linux/pm_runtime.h>

	#define ATLAS_REGMAP_NAME "atlas_ph_regmap"
	#define ATLAS_DRV_NAME "atlas_ph"

	#define ATLAS_REG_DEV_TYPE 0x00
	#define ATLAS_REG_DEV_VERSION 0x01

	#define ATLAS_REG_INT_CONTROL 0x04
	#define ATLAS_REG_INT_CONTROL_EN BIT(3)

	#define ATLAS_REG_PWR_CONTROL 0x06

	#define ATLAS_REG_CALIB_STATUS 0x0d
	#define ATLAS_REG_CALIB_STATUS_MASK 0x07
	#define ATLAS_REG_CALIB_STATUS_LOW BIT(0)
	#define ATLAS_REG_CALIB_STATUS_MID BIT(1)
	#define ATLAS_REG_CALIB_STATUS_HIGH BIT(2)

	#define ATLAS_REG_TEMP_DATA 0x0e
	#define ATLAS_REG_PH_DATA 0x16

	#define ATLAS_PH_INT_TIME_IN_US 450000

	struct atlas_data {
	struct i2c_client *client;
	struct iio_trigger *trig;
	struct regmap *regmap;
	struct irq_work work;

	__be32 buffer[4]; /* 32-bit pH data + 32-bit pad + 64-bit timestamp */
	};

	static const struct regmap_range atlas_volatile_ranges[] = {
	regmap_reg_range(ATLAS_REG_INT_CONTROL, ATLAS_REG_INT_CONTROL),
	regmap_reg_range(ATLAS_REG_PH_DATA, ATLAS_REG_PH_DATA + 4),
	};

	static const struct regmap_access_table atlas_volatile_table = {
	.yes_ranges = atlas_volatile_ranges,
	.n_yes_ranges = ARRAY_SIZE(atlas_volatile_ranges),
	};

	static const struct regmap_config atlas_regmap_config = {
	.name = ATLAS_REGMAP_NAME,

	.reg_bits = 8,
	.val_bits = 8,

	.volatile_table = &atlas_volatile_table,
	.max_register = ATLAS_REG_PH_DATA + 4,
	.cache_type = REGCACHE_RBTREE,
	};

	static const struct iio_chan_spec atlas_channels[] = {
	{
	.type = IIO_PH,
	.info_mask_separate =
	BIT(IIO_CHAN_INFO_RAW) \| BIT(IIO_CHAN_INFO_SCALE),
	.scan_index = 0,
	.scan_type = {
	.sign = 'u',
	.realbits = 32,
	.storagebits = 32,
	.endianness = IIO_BE,
	},
	},
	IIO_CHAN_SOFT_TIMESTAMP(1),
	{
	.type = IIO_TEMP,
	.address = ATLAS_REG_TEMP_DATA,
	.info_mask_separate =
	BIT(IIO_CHAN_INFO_RAW) \| BIT(IIO_CHAN_INFO_SCALE),
	.output = 1,
	.scan_index = -1
	},
	};

	static int atlas_set_powermode(struct atlas_data *data, int on)
	{
	return regmap_write(data->regmap, ATLAS_REG_PWR_CONTROL, on);
	}

	static int atlas_set_interrupt(struct atlas_data *data, bool state)
	{
	return regmap_update_bits(data->regmap, ATLAS_REG_INT_CONTROL,
	ATLAS_REG_INT_CONTROL_EN,
	state ? ATLAS_REG_INT_CONTROL_EN : 0);
	}

	static int atlas_buffer_postenable(struct iio_dev *indio_dev)
	{
	struct atlas_data *data = iio_priv(indio_dev);
	int ret;

	ret = iio_triggered_buffer_postenable(indio_dev);
	if (ret)
	return ret;

	ret = pm_runtime_get_sync(&data->client->dev);
	if (ret < 0) {
	pm_runtime_put_noidle(&data->client->dev);
	return ret;
	}

	return atlas_set_interrupt(data, true);
	}

	static int atlas_buffer_predisable(struct iio_dev *indio_dev)
	{
	struct atlas_data *data = iio_priv(indio_dev);
	int ret;

	ret = iio_triggered_buffer_predisable(indio_dev);
	if (ret)
	return ret;

	ret = atlas_set_interrupt(data, false);
	if (ret)
	return ret;

	pm_runtime_mark_last_busy(&data->client->dev);
	return pm_runtime_put_autosuspend(&data->client->dev);
	}

	static const struct iio_trigger_ops atlas_interrupt_trigger_ops = {
	.owner = THIS_MODULE,
	};

	static const struct iio_buffer_setup_ops atlas_buffer_setup_ops = {
	.postenable = atlas_buffer_postenable,
	.predisable = atlas_buffer_predisable,
	};

	static void atlas_work_handler(struct irq_work *work)
	{
	struct atlas_data *data = container_of(work, struct atlas_data, work);

	iio_trigger_poll(data->trig);
	}

	static irqreturn_t atlas_trigger_handler(int irq, void *private)
	{
	struct iio_poll_func *pf = private;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct atlas_data *data = iio_priv(indio_dev);
	int ret;

	ret = regmap_bulk_read(data->regmap, ATLAS_REG_PH_DATA,
	(u8 *) &data->buffer, sizeof(data->buffer[0]));

	if (!ret)
	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 irqreturn_t atlas_interrupt_handler(int irq, void *private)
	{
	struct iio_dev *indio_dev = private;
	struct atlas_data *data = iio_priv(indio_dev);

	irq_work_queue(&data->work);

	return IRQ_HANDLED;
	}

	static int atlas_read_ph_measurement(struct atlas_data data, __be32 val)
	{
	struct device *dev = &data->client->dev;
	int suspended = pm_runtime_suspended(dev);
	int ret;

	ret = pm_runtime_get_sync(dev);
	if (ret < 0) {
	pm_runtime_put_noidle(dev);
	return ret;
	}

	if (suspended)
	usleep_range(ATLAS_PH_INT_TIME_IN_US,
	ATLAS_PH_INT_TIME_IN_US + 100000);

	ret = regmap_bulk_read(data->regmap, ATLAS_REG_PH_DATA,
	(u8 ) val, sizeof(val));

	pm_runtime_mark_last_busy(dev);
	pm_runtime_put_autosuspend(dev);

	return ret;
	}

	static int atlas_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct atlas_data *data = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW: {
	int ret;
	__be32 reg;

	switch (chan->type) {
	case IIO_TEMP:
	ret = regmap_bulk_read(data->regmap, chan->address,
	(u8 *) &reg, sizeof(reg));
	break;
	case IIO_PH:
	mutex_lock(&indio_dev->mlock);

	if (iio_buffer_enabled(indio_dev))
	ret = -EBUSY;
	else
	ret = atlas_read_ph_measurement(data, &reg);

	mutex_unlock(&indio_dev->mlock);
	break;
	default:
	ret = -EINVAL;
	}

	if (!ret) {
	*val = be32_to_cpu(reg);
	ret = IIO_VAL_INT;
	}
	return ret;
	}
	case IIO_CHAN_INFO_SCALE:
	switch (chan->type) {
	case IIO_TEMP:
	val = 1; / 0.01 */
	*val2 = 100;
	break;
	case IIO_PH:
	val = 1; / 0.001 */
	*val2 = 1000;
	break;
	default:
	return -EINVAL;
	}
	return IIO_VAL_FRACTIONAL;
	}

	return -EINVAL;
	}

	static int atlas_write_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct atlas_data *data = iio_priv(indio_dev);
	__be32 reg = cpu_to_be32(val);

	if (val2 != 0 \|\| val < 0 \|\| val > 20000)
	return -EINVAL;

	if (mask != IIO_CHAN_INFO_RAW \|\| chan->type != IIO_TEMP)
	return -EINVAL;

	return regmap_bulk_write(data->regmap, chan->address,
	&reg, sizeof(reg));
	}

	static const struct iio_info atlas_info = {
	.driver_module = THIS_MODULE,
	.read_raw = atlas_read_raw,
	.write_raw = atlas_write_raw,
	};

	static int atlas_check_calibration(struct atlas_data *data)
	{
	struct device *dev = &data->client->dev;
	int ret;
	unsigned int val;

	ret = regmap_read(data->regmap, ATLAS_REG_CALIB_STATUS, &val);
	if (ret)
	return ret;

	if (!(val & ATLAS_REG_CALIB_STATUS_MASK)) {
	dev_warn(dev, "device has not been calibrated\n");
	return 0;
	}

	if (!(val & ATLAS_REG_CALIB_STATUS_LOW))
	dev_warn(dev, "device missing low point calibration\n");

	if (!(val & ATLAS_REG_CALIB_STATUS_MID))
	dev_warn(dev, "device missing mid point calibration\n");

	if (!(val & ATLAS_REG_CALIB_STATUS_HIGH))
	dev_warn(dev, "device missing high point calibration\n");

	return 0;
	};

	static int atlas_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct atlas_data *data;
	struct iio_trigger *trig;
	struct iio_dev *indio_dev;
	int ret;

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
	if (!indio_dev)
	return -ENOMEM;

	indio_dev->info = &atlas_info;
	indio_dev->name = ATLAS_DRV_NAME;
	indio_dev->channels = atlas_channels;
	indio_dev->num_channels = ARRAY_SIZE(atlas_channels);
	indio_dev->modes = INDIO_BUFFER_SOFTWARE \| INDIO_DIRECT_MODE;
	indio_dev->dev.parent = &client->dev;

	trig = devm_iio_trigger_alloc(&client->dev, "%s-dev%d",
	indio_dev->name, indio_dev->id);

	if (!trig)
	return -ENOMEM;

	data = iio_priv(indio_dev);
	data->client = client;
	data->trig = trig;
	trig->dev.parent = indio_dev->dev.parent;
	trig->ops = &atlas_interrupt_trigger_ops;
	iio_trigger_set_drvdata(trig, indio_dev);

	i2c_set_clientdata(client, indio_dev);

	data->regmap = devm_regmap_init_i2c(client, &atlas_regmap_config);
	if (IS_ERR(data->regmap)) {
	dev_err(&client->dev, "regmap initialization failed\n");
	return PTR_ERR(data->regmap);
	}

	ret = pm_runtime_set_active(&client->dev);
	if (ret)
	return ret;

	if (client->irq <= 0) {
	dev_err(&client->dev, "no valid irq defined\n");
	return -EINVAL;
	}

	ret = atlas_check_calibration(data);
	if (ret)
	return ret;

	ret = iio_trigger_register(trig);
	if (ret) {
	dev_err(&client->dev, "failed to register trigger\n");
	return ret;
	}

	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
	&atlas_trigger_handler, &atlas_buffer_setup_ops);
	if (ret) {
	dev_err(&client->dev, "cannot setup iio trigger\n");
	goto unregister_trigger;
	}

	init_irq_work(&data->work, atlas_work_handler);

	/* interrupt pin toggles on new conversion */
	ret = devm_request_threaded_irq(&client->dev, client->irq,
	NULL, atlas_interrupt_handler,
	IRQF_TRIGGER_RISING \|
	IRQF_TRIGGER_FALLING \| IRQF_ONESHOT,
	"atlas_irq",
	indio_dev);
	if (ret) {
	dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
	goto unregister_buffer;
	}

	ret = atlas_set_powermode(data, 1);
	if (ret) {
	dev_err(&client->dev, "cannot power device on");
	goto unregister_buffer;
	}

	pm_runtime_enable(&client->dev);
	pm_runtime_set_autosuspend_delay(&client->dev, 2500);
	pm_runtime_use_autosuspend(&client->dev);

	ret = iio_device_register(indio_dev);
	if (ret) {
	dev_err(&client->dev, "unable to register device\n");
	goto unregister_pm;
	}

	return 0;

	unregister_pm:
	pm_runtime_disable(&client->dev);
	atlas_set_powermode(data, 0);

	unregister_buffer:
	iio_triggered_buffer_cleanup(indio_dev);

	unregister_trigger:
	iio_trigger_unregister(data->trig);

	return ret;
	}

	static int atlas_remove(struct i2c_client *client)
	{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct atlas_data *data = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);
	iio_trigger_unregister(data->trig);

	pm_runtime_disable(&client->dev);
	pm_runtime_set_suspended(&client->dev);
	pm_runtime_put_noidle(&client->dev);

	return atlas_set_powermode(data, 0);
	}

	#ifdef CONFIG_PM
	static int atlas_runtime_suspend(struct device *dev)
	{
	struct atlas_data *data =
	iio_priv(i2c_get_clientdata(to_i2c_client(dev)));

	return atlas_set_powermode(data, 0);
	}

	static int atlas_runtime_resume(struct device *dev)
	{
	struct atlas_data *data =
	iio_priv(i2c_get_clientdata(to_i2c_client(dev)));

	return atlas_set_powermode(data, 1);
	}
	#endif

	static const struct dev_pm_ops atlas_pm_ops = {
	SET_RUNTIME_PM_OPS(atlas_runtime_suspend,
	atlas_runtime_resume, NULL)
	};

	static const struct i2c_device_id atlas_id[] = {
	{ "atlas-ph-sm", 0 },
	{}
	};
	MODULE_DEVICE_TABLE(i2c, atlas_id);

	static const struct of_device_id atlas_dt_ids[] = {
	{ .compatible = "atlas,ph-sm" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, atlas_dt_ids);

	static struct i2c_driver atlas_driver = {
	.driver = {
	.name = ATLAS_DRV_NAME,
	.of_match_table = of_match_ptr(atlas_dt_ids),
	.pm = &atlas_pm_ops,
	},
	.probe = atlas_probe,
	.remove = atlas_remove,
	.id_table = atlas_id,
	};
	module_i2c_driver(atlas_driver);

	MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
	MODULE_DESCRIPTION("Atlas Scientific pH-SM sensor");
	MODULE_LICENSE("GPL");