drivers/iio/humidity/am2315.c - kernel/msm-4.9 - Gitiles

 /**
  * Aosong AM2315 relative humidity and temperature
  *
  * Copyright (c) 2016, Intel Corporation.
  *
  * This file is subject to the terms and conditions of version 2 of
  * the GNU General Public License. See the file COPYING in the main
  * directory of this archive for more details.
  *
  * 7-bit I2C address: 0x5C.
  */

 #include <linux/acpi.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>

 #define AM2315_REG_HUM_MSB			0x00
 #define AM2315_REG_HUM_LSB			0x01
 #define AM2315_REG_TEMP_MSB			0x02
 #define AM2315_REG_TEMP_LSB			0x03

 #define AM2315_FUNCTION_READ			0x03
 #define AM2315_HUM_OFFSET			2
 #define AM2315_TEMP_OFFSET			4
 #define AM2315_ALL_CHANNEL_MASK			GENMASK(1, 0)

 #define AM2315_DRIVER_NAME			"am2315"

 struct am2315_data {
 	struct i2c_client *client;
 	struct mutex lock;
 	s16 buffer[8]; /* 2x16-bit channels + 2x16 padding + 4x16 timestamp */
 };

 struct am2315_sensor_data {
 	s16 hum_data;
 	s16 temp_data;
 };

 static const struct iio_chan_spec am2315_channels[] = {
 	{
 		.type = IIO_HUMIDITYRELATIVE,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 				      BIT(IIO_CHAN_INFO_SCALE),
 		.scan_index = 0,
 		.scan_type = {
 			.sign = 's',
 			.realbits = 16,
 			.storagebits = 16,
 			.endianness = IIO_CPU,
 		},
 	},
 	{
 		.type = IIO_TEMP,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 				      BIT(IIO_CHAN_INFO_SCALE),
 		.scan_index = 1,
 		.scan_type = {
 			.sign = 's',
 			.realbits = 16,
 			.storagebits = 16,
 			.endianness = IIO_CPU,
 		},
 	},
 	IIO_CHAN_SOFT_TIMESTAMP(2),
 };

 /* CRC calculation algorithm, as specified in the datasheet (page 13). */
 static u16 am2315_crc(u8 *data, u8 nr_bytes)
 {
 	int i;
 	u16 crc = 0xffff;

 	while (nr_bytes--) {
 		crc ^= *data++;
 		for (i = 0; i < 8; i++) {
 			if (crc & 0x01) {
 				crc >>= 1;
 				crc ^= 0xA001;
 			} else {
 				crc >>= 1;
 			}
 		}
 	}

 	return crc;
 }

 /* Simple function that sends a few bytes to the device to wake it up. */
 static void am2315_ping(struct i2c_client *client)
 {
 	i2c_smbus_read_byte_data(client, AM2315_REG_HUM_MSB);
 }

 static int am2315_read_data(struct am2315_data *data,
 			    struct am2315_sensor_data *sensor_data)
 {
 	int ret;
 	/* tx_buf format: <function code> <start addr> <nr of regs to read> */
 	u8 tx_buf[3] = { AM2315_FUNCTION_READ, AM2315_REG_HUM_MSB, 4 };
 	/*
 	 * rx_buf format:
 	 * <function code> <number of registers read>
 	 * <humidity MSB> <humidity LSB> <temp MSB> <temp LSB>
 	 * <CRC LSB> <CRC MSB>
 	 */
 	u8 rx_buf[8];
 	u16 crc;

 	/* First wake up the device. */
 	am2315_ping(data->client);

 	mutex_lock(&data->lock);
 	ret = i2c_master_send(data->client, tx_buf, sizeof(tx_buf));
 	if (ret < 0) {
 		dev_err(&data->client->dev, "failed to send read request\n");
 		goto exit_unlock;
 	}
 	/* Wait 2-3 ms, then read back the data sent by the device. */
 	usleep_range(2000, 3000);
 	/* Do a bulk data read, then pick out what we need. */
 	ret = i2c_master_recv(data->client, rx_buf, sizeof(rx_buf));
 	if (ret < 0) {
 		dev_err(&data->client->dev, "failed to read sensor data\n");
 		goto exit_unlock;
 	}
 	mutex_unlock(&data->lock);
 	/*
 	 * Do a CRC check on the data and compare it to the value
 	 * calculated by the device.
 	 */
 	crc = am2315_crc(rx_buf, sizeof(rx_buf) - 2);
 	if ((crc & 0xff) != rx_buf[6] || (crc >> 8) != rx_buf[7]) {
 		dev_err(&data->client->dev, "failed to verify sensor data\n");
 		return -EIO;
 	}

 	sensor_data->hum_data = (rx_buf[AM2315_HUM_OFFSET] << 8) |
 				 rx_buf[AM2315_HUM_OFFSET + 1];
 	sensor_data->temp_data = (rx_buf[AM2315_TEMP_OFFSET] << 8) |
 				  rx_buf[AM2315_TEMP_OFFSET + 1];

 	return ret;

 exit_unlock:
 	mutex_unlock(&data->lock);
 	return ret;
 }

 static irqreturn_t am2315_trigger_handler(int irq, void *p)
 {
 	int i;
 	int ret;
 	int bit;
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct am2315_data *data = iio_priv(indio_dev);
 	struct am2315_sensor_data sensor_data;

 	ret = am2315_read_data(data, &sensor_data);
 	if (ret < 0)
 		goto err;

 	mutex_lock(&data->lock);
 	if (*(indio_dev->active_scan_mask) == AM2315_ALL_CHANNEL_MASK) {
 		data->buffer[0] = sensor_data.hum_data;
 		data->buffer[1] = sensor_data.temp_data;
 	} else {
 		i = 0;
 		for_each_set_bit(bit, indio_dev->active_scan_mask,
 				 indio_dev->masklength) {
 			data->buffer[i] = (bit ? sensor_data.temp_data :
 						 sensor_data.hum_data);
 			i++;
 		}
 	}
 	mutex_unlock(&data->lock);

 	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
 					   pf->timestamp);
 err:
 	iio_trigger_notify_done(indio_dev->trig);
 	return IRQ_HANDLED;
 }

 static int am2315_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int *val, int *val2, long mask)
 {
 	int ret;
 	struct am2315_sensor_data sensor_data;
 	struct am2315_data *data = iio_priv(indio_dev);

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		ret = am2315_read_data(data, &sensor_data);
 		if (ret < 0)
 			return ret;
 		*val = (chan->type == IIO_HUMIDITYRELATIVE) ?
 				sensor_data.hum_data : sensor_data.temp_data;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		*val = 100;
 		return IIO_VAL_INT;
 	}

 	return -EINVAL;
 }

 static const struct iio_info am2315_info = {
 	.driver_module		= THIS_MODULE,
 	.read_raw		= am2315_read_raw,
 };

 static int am2315_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	int ret;
 	struct iio_dev *indio_dev;
 	struct am2315_data *data;

 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (!indio_dev) {
 		dev_err(&client->dev, "iio allocation failed!\n");
 		return -ENOMEM;
 	}

 	data = iio_priv(indio_dev);
 	data->client = client;
 	i2c_set_clientdata(client, indio_dev);
 	mutex_init(&data->lock);

 	indio_dev->dev.parent = &client->dev;
 	indio_dev->info = &am2315_info;
 	indio_dev->name = AM2315_DRIVER_NAME;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = am2315_channels;
 	indio_dev->num_channels = ARRAY_SIZE(am2315_channels);

 	ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
 					 am2315_trigger_handler, NULL);
 	if (ret < 0) {
 		dev_err(&client->dev, "iio triggered buffer setup failed\n");
 		return ret;
 	}

 	ret = iio_device_register(indio_dev);
 	if (ret < 0)
 		goto err_buffer_cleanup;

 	return 0;

 err_buffer_cleanup:
 	iio_triggered_buffer_cleanup(indio_dev);
 	return ret;
 }

 static int am2315_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);

 	iio_device_unregister(indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);

 	return 0;
 }

 static const struct i2c_device_id am2315_i2c_id[] = {
 	{"am2315", 0},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, am2315_i2c_id);

 static const struct acpi_device_id am2315_acpi_id[] = {
 	{"AOS2315", 0},
 	{}
 };

 MODULE_DEVICE_TABLE(acpi, am2315_acpi_id);

 static struct i2c_driver am2315_driver = {
 	.driver = {
 		.name = "am2315",
 		.acpi_match_table = ACPI_PTR(am2315_acpi_id),
 	},
 	.probe =            am2315_probe,
 	.remove =	    am2315_remove,
 	.id_table =         am2315_i2c_id,
 };

 module_i2c_driver(am2315_driver);

 MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
 MODULE_DESCRIPTION("Aosong AM2315 relative humidity and temperature");
 MODULE_LICENSE("GPL v2");
	/**
	* Aosong AM2315 relative humidity and temperature
	*
	* Copyright (c) 2016, Intel Corporation.
	*
	* This file is subject to the terms and conditions of version 2 of
	* the GNU General Public License. See the file COPYING in the main
	* directory of this archive for more details.
	*
	* 7-bit I2C address: 0x5C.
	*/

	#include <linux/acpi.h>
	#include <linux/delay.h>
	#include <linux/i2c.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/iio/buffer.h>
	#include <linux/iio/iio.h>
	#include <linux/iio/sysfs.h>
	#include <linux/iio/trigger_consumer.h>
	#include <linux/iio/triggered_buffer.h>

	#define AM2315_REG_HUM_MSB 0x00
	#define AM2315_REG_HUM_LSB 0x01
	#define AM2315_REG_TEMP_MSB 0x02
	#define AM2315_REG_TEMP_LSB 0x03

	#define AM2315_FUNCTION_READ 0x03
	#define AM2315_HUM_OFFSET 2
	#define AM2315_TEMP_OFFSET 4
	#define AM2315_ALL_CHANNEL_MASK GENMASK(1, 0)

	#define AM2315_DRIVER_NAME "am2315"

	struct am2315_data {
	struct i2c_client *client;
	struct mutex lock;
	s16 buffer[8]; /* 2x16-bit channels + 2x16 padding + 4x16 timestamp */
	};

	struct am2315_sensor_data {
	s16 hum_data;
	s16 temp_data;
	};

	static const struct iio_chan_spec am2315_channels[] = {
	{
	.type = IIO_HUMIDITYRELATIVE,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_SCALE),
	.scan_index = 0,
	.scan_type = {
	.sign = 's',
	.realbits = 16,
	.storagebits = 16,
	.endianness = IIO_CPU,
	},
	},
	{
	.type = IIO_TEMP,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_SCALE),
	.scan_index = 1,
	.scan_type = {
	.sign = 's',
	.realbits = 16,
	.storagebits = 16,
	.endianness = IIO_CPU,
	},
	},
	IIO_CHAN_SOFT_TIMESTAMP(2),
	};

	/* CRC calculation algorithm, as specified in the datasheet (page 13). */
	static u16 am2315_crc(u8 *data, u8 nr_bytes)
	{
	int i;
	u16 crc = 0xffff;

	while (nr_bytes--) {
	crc ^= *data++;
	for (i = 0; i < 8; i++) {
	if (crc & 0x01) {
	crc >>= 1;
	crc ^= 0xA001;
	} else {
	crc >>= 1;
	}
	}
	}

	return crc;
	}

	/* Simple function that sends a few bytes to the device to wake it up. */
	static void am2315_ping(struct i2c_client *client)
	{
	i2c_smbus_read_byte_data(client, AM2315_REG_HUM_MSB);
	}

	static int am2315_read_data(struct am2315_data *data,
	struct am2315_sensor_data *sensor_data)
	{
	int ret;
	/* tx_buf format: <function code> <start addr> <nr of regs to read> */
	u8 tx_buf[3] = { AM2315_FUNCTION_READ, AM2315_REG_HUM_MSB, 4 };
	/*
	* rx_buf format:
	* <function code> <number of registers read>
	* <humidity MSB> <humidity LSB> <temp MSB> <temp LSB>
	* <CRC LSB> <CRC MSB>
	*/
	u8 rx_buf[8];
	u16 crc;

	/* First wake up the device. */
	am2315_ping(data->client);

	mutex_lock(&data->lock);
	ret = i2c_master_send(data->client, tx_buf, sizeof(tx_buf));
	if (ret < 0) {
	dev_err(&data->client->dev, "failed to send read request\n");
	goto exit_unlock;
	}
	/* Wait 2-3 ms, then read back the data sent by the device. */
	usleep_range(2000, 3000);
	/* Do a bulk data read, then pick out what we need. */
	ret = i2c_master_recv(data->client, rx_buf, sizeof(rx_buf));
	if (ret < 0) {
	dev_err(&data->client->dev, "failed to read sensor data\n");
	goto exit_unlock;
	}
	mutex_unlock(&data->lock);
	/*
	* Do a CRC check on the data and compare it to the value
	* calculated by the device.
	*/
	crc = am2315_crc(rx_buf, sizeof(rx_buf) - 2);
	if ((crc & 0xff) != rx_buf[6] \|\| (crc >> 8) != rx_buf[7]) {
	dev_err(&data->client->dev, "failed to verify sensor data\n");
	return -EIO;
	}

	sensor_data->hum_data = (rx_buf[AM2315_HUM_OFFSET] << 8) \|
	rx_buf[AM2315_HUM_OFFSET + 1];
	sensor_data->temp_data = (rx_buf[AM2315_TEMP_OFFSET] << 8) \|
	rx_buf[AM2315_TEMP_OFFSET + 1];

	return ret;

	exit_unlock:
	mutex_unlock(&data->lock);
	return ret;
	}

	static irqreturn_t am2315_trigger_handler(int irq, void *p)
	{
	int i;
	int ret;
	int bit;
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct am2315_data *data = iio_priv(indio_dev);
	struct am2315_sensor_data sensor_data;

	ret = am2315_read_data(data, &sensor_data);
	if (ret < 0)
	goto err;

	mutex_lock(&data->lock);
	if (*(indio_dev->active_scan_mask) == AM2315_ALL_CHANNEL_MASK) {
	data->buffer[0] = sensor_data.hum_data;
	data->buffer[1] = sensor_data.temp_data;
	} else {
	i = 0;
	for_each_set_bit(bit, indio_dev->active_scan_mask,
	indio_dev->masklength) {
	data->buffer[i] = (bit ? sensor_data.temp_data :
	sensor_data.hum_data);
	i++;
	}
	}
	mutex_unlock(&data->lock);

	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
	pf->timestamp);
	err:
	iio_trigger_notify_done(indio_dev->trig);
	return IRQ_HANDLED;
	}

	static int am2315_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	int ret;
	struct am2315_sensor_data sensor_data;
	struct am2315_data *data = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	ret = am2315_read_data(data, &sensor_data);
	if (ret < 0)
	return ret;
	*val = (chan->type == IIO_HUMIDITYRELATIVE) ?
	sensor_data.hum_data : sensor_data.temp_data;
	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	*val = 100;
	return IIO_VAL_INT;
	}

	return -EINVAL;
	}

	static const struct iio_info am2315_info = {
	.driver_module = THIS_MODULE,
	.read_raw = am2315_read_raw,
	};

	static int am2315_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	int ret;
	struct iio_dev *indio_dev;
	struct am2315_data *data;

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
	if (!indio_dev) {
	dev_err(&client->dev, "iio allocation failed!\n");
	return -ENOMEM;
	}

	data = iio_priv(indio_dev);
	data->client = client;
	i2c_set_clientdata(client, indio_dev);
	mutex_init(&data->lock);

	indio_dev->dev.parent = &client->dev;
	indio_dev->info = &am2315_info;
	indio_dev->name = AM2315_DRIVER_NAME;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = am2315_channels;
	indio_dev->num_channels = ARRAY_SIZE(am2315_channels);

	ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
	am2315_trigger_handler, NULL);
	if (ret < 0) {
	dev_err(&client->dev, "iio triggered buffer setup failed\n");
	return ret;
	}

	ret = iio_device_register(indio_dev);
	if (ret < 0)
	goto err_buffer_cleanup;

	return 0;

	err_buffer_cleanup:
	iio_triggered_buffer_cleanup(indio_dev);
	return ret;
	}

	static int am2315_remove(struct i2c_client *client)
	{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);

	return 0;
	}

	static const struct i2c_device_id am2315_i2c_id[] = {
	{"am2315", 0},
	{}
	};
	MODULE_DEVICE_TABLE(i2c, am2315_i2c_id);

	static const struct acpi_device_id am2315_acpi_id[] = {
	{"AOS2315", 0},
	{}
	};

	MODULE_DEVICE_TABLE(acpi, am2315_acpi_id);

	static struct i2c_driver am2315_driver = {
	.driver = {
	.name = "am2315",
	.acpi_match_table = ACPI_PTR(am2315_acpi_id),
	},
	.probe = am2315_probe,
	.remove = am2315_remove,
	.id_table = am2315_i2c_id,
	};

	module_i2c_driver(am2315_driver);

	MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
	MODULE_DESCRIPTION("Aosong AM2315 relative humidity and temperature");
	MODULE_LICENSE("GPL v2");