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linux/drivers/iio/humidity/ens210.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* ens210.c - Support for ScioSense ens210 temperature & humidity sensor family
*
* (7-bit I2C slave address 0x43 ENS210)
* (7-bit I2C slave address 0x43 ENS210A)
* (7-bit I2C slave address 0x44 ENS211)
* (7-bit I2C slave address 0x45 ENS212)
* (7-bit I2C slave address 0x46 ENS213A)
* (7-bit I2C slave address 0x47 ENS215)
*
* Datasheet:
* https://www.sciosense.com/wp-content/uploads/2024/04/ENS21x-Datasheet.pdf
* https://www.sciosense.com/wp-content/uploads/2023/12/ENS210-Datasheet.pdf
*/
#include <linux/crc7.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/unaligned.h>
/* register definitions */
#define ENS210_REG_PART_ID 0x00
#define ENS210_REG_DIE_REV 0x02
#define ENS210_REG_UID 0x04
#define ENS210_REG_SYS_CTRL 0x10
#define ENS210_REG_SYS_STAT 0x11
#define ENS210_REG_SENS_RUN 0x21
#define ENS210_REG_SENS_START 0x22
#define ENS210_REG_SENS_STOP 0x23
#define ENS210_REG_SENS_STAT 0x24
#define ENS210_REG_T_VAL 0x30
#define ENS210_REG_H_VAL 0x33
/* value definitions */
#define ENS210_SENS_START_T_START BIT(0)
#define ENS210_SENS_START_H_START BIT(1)
#define ENS210_SENS_STAT_T_ACTIVE BIT(0)
#define ENS210_SENS_STAT_H_ACTIVE BIT(1)
#define ENS210_SYS_CTRL_LOW_POWER_ENABLE BIT(0)
#define ENS210_SYS_CTRL_SYS_RESET BIT(7)
#define ENS210_SYS_STAT_SYS_ACTIVE BIT(0)
enum ens210_partnumber {
ENS210 = 0x0210,
ENS210A = 0xa210,
ENS211 = 0x0211,
ENS212 = 0x0212,
ENS213A = 0xa213,
ENS215 = 0x0215,
};
/**
* struct ens210_chip_info - Humidity/Temperature chip specific information
* @name: name of device
* @part_id: chip identifier
* @conv_time_msec: time for conversion calculation in m/s
*/
struct ens210_chip_info {
const char *name;
enum ens210_partnumber part_id;
unsigned int conv_time_msec;
};
/**
* struct ens210_data - Humidity/Temperature sensor device structure
* @client: i2c client
* @chip_info: chip specific information
* @lock: lock protecting against simultaneous callers of get_measurement
* since multiple uninterrupted transactions are required
*/
struct ens210_data {
struct i2c_client *client;
const struct ens210_chip_info *chip_info;
struct mutex lock;
};
/* calculate 17-bit crc7 */
static u8 ens210_crc7(u32 val)
{
unsigned int val_be = (val & 0x1ffff) >> 0x8;
return crc7_be(0xde, (u8 *)&val_be, 3) >> 1;
}
static int ens210_get_measurement(struct iio_dev *indio_dev, bool temp, int *val)
{
struct ens210_data *data = iio_priv(indio_dev);
struct device *dev = &data->client->dev;
u32 regval;
u8 regval_le[3];
int ret;
/* assert read */
ret = i2c_smbus_write_byte_data(data->client, ENS210_REG_SENS_START,
temp ? ENS210_SENS_START_T_START :
ENS210_SENS_START_H_START);
if (ret)
return ret;
/* wait for conversion to be ready */
msleep(data->chip_info->conv_time_msec);
ret = i2c_smbus_read_byte_data(data->client, ENS210_REG_SENS_STAT);
if (ret < 0)
return ret;
/* perform read */
ret = i2c_smbus_read_i2c_block_data(
data->client, temp ? ENS210_REG_T_VAL : ENS210_REG_H_VAL, 3,
regval_le);
if (ret < 0) {
dev_err(dev, "failed to read register");
return -EIO;
}
if (ret != 3) {
dev_err(dev, "expected 3 bytes, received %d\n", ret);
return -EIO;
}
regval = get_unaligned_le24(regval_le);
if (ens210_crc7(regval) != ((regval >> 17) & 0x7f)) {
dev_err(dev, "invalid crc\n");
return -EIO;
}
if (!((regval >> 16) & 0x1)) {
dev_err(dev, "data is not valid");
return -EIO;
}
*val = regval & GENMASK(15, 0);
return IIO_VAL_INT;
}
static int ens210_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
{
struct ens210_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
scoped_guard(mutex, &data->lock) {
ret = ens210_get_measurement(
indio_dev, channel->type == IIO_TEMP, val);
if (ret)
return ret;
return IIO_VAL_INT;
}
return -EINVAL; /* compiler warning workaround */
case IIO_CHAN_INFO_SCALE:
if (channel->type == IIO_TEMP) {
*val = 15;
*val2 = 625000;
} else {
*val = 1;
*val2 = 953125;
}
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_OFFSET:
*val = -17481;
*val2 = 600000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
static const struct iio_chan_spec ens210_channels[] = {
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_OFFSET),
},
{
.type = IIO_HUMIDITYRELATIVE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
}
};
static const struct iio_info ens210_info = {
.read_raw = ens210_read_raw,
};
static int ens210_probe(struct i2c_client *client)
{
struct ens210_data *data;
struct iio_dev *indio_dev;
uint16_t part_id;
int ret;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
I2C_FUNC_SMBUS_WRITE_BYTE |
I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
return dev_err_probe(&client->dev, -EOPNOTSUPP,
"adapter does not support some i2c transactions\n");
}
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
data->client = client;
mutex_init(&data->lock);
data->chip_info = i2c_get_match_data(client);
ret = devm_regulator_get_enable(&client->dev, "vdd");
if (ret)
return ret;
/* reset device */
ret = i2c_smbus_write_byte_data(client, ENS210_REG_SYS_CTRL,
ENS210_SYS_CTRL_SYS_RESET);
if (ret)
return ret;
/* wait for device to become active */
usleep_range(4000, 5000);
/* disable low power mode */
ret = i2c_smbus_write_byte_data(client, ENS210_REG_SYS_CTRL, 0x00);
if (ret)
return ret;
/* wait for device to finish */
usleep_range(4000, 5000);
/* get part_id */
ret = i2c_smbus_read_word_data(client, ENS210_REG_PART_ID);
if (ret < 0)
return ret;
part_id = ret;
if (part_id != data->chip_info->part_id) {
dev_info(&client->dev,
"Part ID does not match (0x%04x != 0x%04x)\n", part_id,
data->chip_info->part_id);
}
/* reenable low power */
ret = i2c_smbus_write_byte_data(client, ENS210_REG_SYS_CTRL,
ENS210_SYS_CTRL_LOW_POWER_ENABLE);
if (ret)
return ret;
indio_dev->name = data->chip_info->name;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ens210_channels;
indio_dev->num_channels = ARRAY_SIZE(ens210_channels);
indio_dev->info = &ens210_info;
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct ens210_chip_info ens210_chip_info_data = {
.name = "ens210",
.part_id = ENS210,
.conv_time_msec = 130,
};
static const struct ens210_chip_info ens210a_chip_info_data = {
.name = "ens210a",
.part_id = ENS210A,
.conv_time_msec = 130,
};
static const struct ens210_chip_info ens211_chip_info_data = {
.name = "ens211",
.part_id = ENS211,
.conv_time_msec = 32,
};
static const struct ens210_chip_info ens212_chip_info_data = {
.name = "ens212",
.part_id = ENS212,
.conv_time_msec = 32,
};
static const struct ens210_chip_info ens213a_chip_info_data = {
.name = "ens213a",
.part_id = ENS213A,
.conv_time_msec = 130,
};
static const struct ens210_chip_info ens215_chip_info_data = {
.name = "ens215",
.part_id = ENS215,
.conv_time_msec = 130,
};
static const struct of_device_id ens210_of_match[] = {
{ .compatible = "sciosense,ens210", .data = &ens210_chip_info_data },
{ .compatible = "sciosense,ens210a", .data = &ens210a_chip_info_data },
{ .compatible = "sciosense,ens211", .data = &ens211_chip_info_data },
{ .compatible = "sciosense,ens212", .data = &ens212_chip_info_data },
{ .compatible = "sciosense,ens213a", .data = &ens213a_chip_info_data },
{ .compatible = "sciosense,ens215", .data = &ens215_chip_info_data },
{ }
};
MODULE_DEVICE_TABLE(of, ens210_of_match);
static const struct i2c_device_id ens210_id_table[] = {
{ "ens210", (kernel_ulong_t)&ens210_chip_info_data },
{ "ens210a", (kernel_ulong_t)&ens210a_chip_info_data },
{ "ens211", (kernel_ulong_t)&ens211_chip_info_data },
{ "ens212", (kernel_ulong_t)&ens212_chip_info_data },
{ "ens213a", (kernel_ulong_t)&ens213a_chip_info_data },
{ "ens215", (kernel_ulong_t)&ens215_chip_info_data },
{ }
};
MODULE_DEVICE_TABLE(i2c, ens210_id_table);
static struct i2c_driver ens210_driver = {
.probe = ens210_probe,
.id_table = ens210_id_table,
.driver = {
.name = "ens210",
.of_match_table = ens210_of_match,
},
};
module_i2c_driver(ens210_driver);
MODULE_DESCRIPTION("ScioSense ENS210 temperature and humidity sensor driver");
MODULE_AUTHOR("Joshua Felmeden <jfelmeden@thegoodpenguin.co.uk>");
MODULE_LICENSE("GPL");