On Sat, Jun 11, 2016 at 10:13 PM, Matt Ranostay <mranostay@xxxxxxxxx> wrote:
> Add support for the Sensirion SHT31 humidity + temperature sensor.
>
> Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx>
> ---
> .../devicetree/bindings/i2c/trivial-devices.txt | 1 +
> drivers/iio/humidity/Kconfig | 11 +
> drivers/iio/humidity/Makefile | 1 +
> drivers/iio/humidity/sht31.c | 416 +++++++++++++++++++++
> 4 files changed, 429 insertions(+)
> create mode 100644 drivers/iio/humidity/sht31.c
>
> diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> index 539874490492..a651ccd15459 100644
> --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> @@ -78,6 +78,7 @@ ricoh,rs5c372b I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
> ricoh,rv5c386 I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
> ricoh,rv5c387a I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
> samsung,24ad0xd1 S524AD0XF1 (128K/256K-bit Serial EEPROM for Low Power)
> +sensirion,sht31 Sensirion SHT31 humidity + temperature sensor
> sgx,vz89x SGX Sensortech VZ89X Sensors
> sii,s35390a 2-wire CMOS real-time clock
> skyworks,sky81452 Skyworks SKY81452: Six-Channel White LED Driver with Touch Panel Bias Supply
> diff --git a/drivers/iio/humidity/Kconfig b/drivers/iio/humidity/Kconfig
> index 738a86d9e4a9..21bff72511a5 100644
> --- a/drivers/iio/humidity/Kconfig
> +++ b/drivers/iio/humidity/Kconfig
> @@ -45,6 +45,17 @@ config HTU21
> This driver can also be built as a module. If so, the module will
> be called htu21.
>
> +config SHT31
> + tristate "Sensirion SHT31 humidity and temperature sensor"
> + depends on I2C
> + select CRC8
> + help
> + If you say yes here you support for the Sensirion SHT31 humidity and
> + temperature sensor.
> +
> + This driver can also be built as a module. If so, the module will be
> + called sht31.
> +
> config SI7005
> tristate "SI7005 relative humidity and temperature sensor"
> depends on I2C
> diff --git a/drivers/iio/humidity/Makefile b/drivers/iio/humidity/Makefile
> index 4a73442fcd9c..a3b7727d47bf 100644
> --- a/drivers/iio/humidity/Makefile
> +++ b/drivers/iio/humidity/Makefile
> @@ -6,5 +6,6 @@ obj-$(CONFIG_AM2315) += am2315.o
> obj-$(CONFIG_DHT11) += dht11.o
> obj-$(CONFIG_HDC100X) += hdc100x.o
> obj-$(CONFIG_HTU21) += htu21.o
> +obj-$(CONFIG_SHT31) += sht31.o
> obj-$(CONFIG_SI7005) += si7005.o
> obj-$(CONFIG_SI7020) += si7020.o
> diff --git a/drivers/iio/humidity/sht31.c b/drivers/iio/humidity/sht31.c
> new file mode 100644
> index 000000000000..c1d74dcaf8c6
> --- /dev/null
> +++ b/drivers/iio/humidity/sht31.c
> @@ -0,0 +1,416 @@
> +/*
> + * sht31.c - Support for the Sensirion SHT31 temperature + humidity sensor
> + *
> + * 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.
> + *
> + */
> +
> +#include <linux/crc8.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/iio/trigger_consumer.h>
> +
> +#define SHT31_DRV_NAME "sht31"
> +
> +#define SHT31_HEATER_CMD_MSB 0x30
> +#define SHT31_HEATER_CMD_ENABLE 0x6d
> +#define SHT31_HEATER_CMD_DISABLE 0x66
> +
> +#define SHT31_MEASUREMENT_CMD_MSB (0x2C << 8)
> +
> +#define SHT31_STATUS_CMD 0xF32D
> +#define SHT31_STATUS_CMD_CHKSUM BIT(0)
> +
> +struct sht31_data {
> + struct iio_dev *indio_dev;
> + struct i2c_client *client;
> + struct mutex lock;
> +
> + /* config */
> + int heater_status;
> + int it_time;
> +
> + u8 crc_table[CRC8_TABLE_SIZE];
> + u16 buffer[8]; /* 4 byte data + 2 byte pad + 8 byte */
> +};
> +
> +static const struct iio_chan_spec sht31_channels[] = {
> + {
> + .type = IIO_TEMP,
> + .address = 0,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_SCALE) |
> + BIT(IIO_CHAN_INFO_OFFSET),
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
> + .scan_index = 0,
> + .scan_type = {
> + .sign = 'u',
> + .realbits = 16,
> + .storagebits = 16,
> + },
> + },
> + {
> + .type = IIO_HUMIDITYRELATIVE,
> + .address = 1,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_SCALE),
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
> + .scan_index = 1,
> + .scan_type = {
> + .sign = 'u',
> + .realbits = 16,
> + .storagebits = 16,
> + },
> + },
> + IIO_CHAN_SOFT_TIMESTAMP(2),
> + {
> + .type = IIO_CURRENT,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> + .extend_name = "heater",
> + .scan_index = -1,
> + .output = 1,
> + },
> +};
> +
> +static IIO_CONST_ATTR(integration_time_available,
> + "0.0025 0.0045 0.0125");
> +
> +static IIO_CONST_ATTR(out_current_heater_raw_available,
> + "0 1");
> +
> +/* integration time + LSB of I2C command */
> +static const int sht31_integration_time[][2] = {
> + {2500, 0x10},
> + {4500, 0x0d},
> + {12500, 0x06}
> +};
> +
> +static const unsigned long sht31_scan_masks[] = {0x3, 0};
> +
> +static struct attribute *sht31_attributes[] = {
> + &iio_const_attr_integration_time_available.dev_attr.attr,
> + &iio_const_attr_out_current_heater_raw_available.dev_attr.attr,
> + NULL
> +};
> +
> +static struct attribute_group sht31_attribute_group = {
> + .attrs = sht31_attributes,
> +};
> +
> +static int sht31_crc8_check(struct sht31_data *data, u8 *vals)
> +{
> + int ret = crc8(data->crc_table, vals, 2, 0xff);
> +
> + if (ret != vals[2])
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static int sht31_get_measurement(struct sht31_data *data, u16 *buf)
> +{
> + struct i2c_client *client = data->client;
> + struct i2c_msg msg[2];
> + u16 reg = cpu_to_be16(SHT31_MEASUREMENT_CMD_MSB |
> + sht31_integration_time[data->it_time][1]);
> + u8 vals[6];
> + int ret, i;
> +
> + msg[0].addr = client->addr;
> + msg[0].flags = client->flags;
> + msg[0].len = 2;
> + msg[0].buf = (char *) ®
> +
> + msg[1].addr = client->addr;
> + msg[1].flags = client->flags | I2C_M_RD;
> + msg[1].len = sizeof(vals);
> + msg[1].buf = (char *) &vals;
> +
> + ret = i2c_transfer(client->adapter, msg, 2);
> + if (ret != 2)
> + return -EIO;
> +
> + for (i = 0; i < 2; i++) {
> + ret = sht31_crc8_check(data, (u8 *) &vals[3 * i]);
> + if (ret)
> + return -EINVAL;
> + *buf++ = be16_to_cpu(*((u16 *) &vals[3 * i]));
> + }
> +
> + return 0;
> +}
> +
> +static irqreturn_t sht31_trigger_handler(int irq, void *private)
> +{
> + struct iio_poll_func *pf = private;
> + struct iio_dev *indio_dev = pf->indio_dev;
> + struct sht31_data *data = iio_priv(indio_dev);
> + int ret;
> +
> + ret = sht31_get_measurement(data, data->buffer);
> + 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 int sht31_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + struct sht31_data *data = iio_priv(indio_dev);
> + int ret = -EINVAL;
> + u16 buf[2];
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_INT_TIME:
> + mutex_lock(&data->lock);
> + *val = 0;
> + *val2 = sht31_integration_time[data->it_time][0];
> + ret = IIO_VAL_INT_PLUS_MICRO;
> + mutex_unlock(&data->lock);
> + break;
> + case IIO_CHAN_INFO_RAW:
> + switch (chan->type) {
> + case IIO_HUMIDITYRELATIVE:
> + case IIO_TEMP:
> + if (iio_device_claim_direct_mode(indio_dev))
> + return -EBUSY;
> +
> + ret = sht31_get_measurement(data, (u16 *) &buf);
> + if (!ret) {
> + *val = buf[chan->address];
> + ret = IIO_VAL_INT;
> + }
> + iio_device_release_direct_mode(indio_dev);
> + break;
> + case IIO_CURRENT:
> + mutex_lock(&data->lock);
> + *val = data->heater_status;
> + ret = IIO_VAL_INT;
> + mutex_unlock(&data->lock);
> + break;
> + default:
> + return -EINVAL;
> + }
> + break;
> + case IIO_CHAN_INFO_SCALE:
> + switch (chan->type) {
> + case IIO_HUMIDITYRELATIVE:
> + *val = 100;
> + *val2 = 65535;
> + break;
> + case IIO_TEMP:
> + *val = 175000;
> + *val2 = 65535;
> + break;
> + default:
> + return -EINVAL;
> + }
> + ret = IIO_VAL_FRACTIONAL;
> + break;
> + case IIO_CHAN_INFO_OFFSET:
> + *val = 18349; /* 18349.8 */
> + *val2 = 800000;
*doh* doublechecking my maths for the calculation I think it should be
the following after all 16851.857142
> + ret = IIO_VAL_INT_PLUS_MICRO;
> + break;
> + }
> +
> + return ret;
> +}
> +
> +static int sht31_set_it_time(struct sht31_data *data, int val2)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(sht31_integration_time); i++) {
> + if (sht31_integration_time[i][0] == val2) {
> + data->it_time = i;
> + return 0;
> + }
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int sht31_validate_checksum(struct sht31_data *data)
> +{
> + struct i2c_client *client = data->client;
> + struct i2c_msg msg[2];
> + u16 reg = cpu_to_be16(SHT31_STATUS_CMD);
> + u8 vals[3];
> + int ret;
> +
> + msg[0].addr = client->addr;
> + msg[0].flags = client->flags;
> + msg[0].len = 2;
> + msg[0].buf = (char *) ®
> +
> + msg[1].addr = client->addr;
> + msg[1].flags = client->flags | I2C_M_RD;
> + msg[1].len = sizeof(vals);
> + msg[1].buf = (char *) &vals;
> +
> + ret = i2c_transfer(client->adapter, msg, 2);
> + if (ret != 2)
> + return -EIO;
> +
> + ret = sht31_crc8_check(data, (u8 *) &vals);
> + if (ret)
> + return ret;
> +
> + return (vals[1] & SHT31_STATUS_CMD_CHKSUM) ? -EINVAL : 0;
> +}
> +
> +static int sht31_set_heater_status(struct sht31_data *data, int val)
> +{
> + int ret;
> +
> + ret = i2c_smbus_write_byte_data(data->client, SHT31_HEATER_CMD_MSB,
> + val ? SHT31_HEATER_CMD_ENABLE : SHT31_HEATER_CMD_DISABLE);
> + if (ret < 0)
> + return ret;
> +
> + ret = sht31_validate_checksum(data);
> + if (!ret)
> + data->heater_status = !!val;
> +
> + return ret;
> +}
> +
> +static int sht31_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int val, int val2, long mask)
> +{
> + struct sht31_data *data = iio_priv(indio_dev);
> + int ret = -EINVAL;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_INT_TIME:
> + if (val != 0)
> + return -EINVAL;
> +
> + mutex_lock(&data->lock);
> + ret = sht31_set_it_time(data, val2);
> + mutex_unlock(&data->lock);
> + break;
> + case IIO_CHAN_INFO_RAW:
> + if (chan->type != IIO_CURRENT || val2 != 0)
> + return -EINVAL;
> +
> + mutex_lock(&data->lock);
> + ret = sht31_set_heater_status(data, val);
> + mutex_unlock(&data->lock);
> + break;
> + }
> +
> + return ret;
> +}
> +
> +static const struct iio_info sht31_info = {
> + .driver_module = THIS_MODULE,
> + .read_raw = sht31_read_raw,
> + .write_raw = sht31_write_raw,
> + .attrs = &sht31_attribute_group,
> +};
> +
> +static int sht31_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct sht31_data *data;
> + struct iio_dev *indio_dev;
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> + if (!indio_dev)
> + return -ENOMEM;
> + data = iio_priv(indio_dev);
> +
> + indio_dev->info = &sht31_info;
> + indio_dev->name = SHT31_DRV_NAME;
> + indio_dev->channels = sht31_channels;
> + indio_dev->num_channels = ARRAY_SIZE(sht31_channels);
> + indio_dev->available_scan_masks = sht31_scan_masks;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->dev.parent = &client->dev;
> +
> + i2c_set_clientdata(client, indio_dev);
> +
> + data->client = client;
> + data->indio_dev = indio_dev;
> + mutex_init(&data->lock);
> +
> + /* CRC polynomial x8 + x5 + x4 + 1 */
> + crc8_populate_msb(data->crc_table, 0x31);
> +
> + ret = iio_triggered_buffer_setup(indio_dev, NULL,
> + sht31_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 sht31_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 of_device_id sht31_dt_ids[] = {
> + { .compatible = "sensirion,sht31" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, sht31_dt_ids);
> +
> +static const struct i2c_device_id sht31_id[] = {
> + { "sht31", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, sht31_id);
> +
> +static struct i2c_driver sht31_driver = {
> + .driver = {
> + .name = SHT31_DRV_NAME,
> + },
> + .probe = sht31_probe,
> + .remove = sht31_remove,
> + .id_table = sht31_id,
> +};
> +module_i2c_driver(sht31_driver);
> +
> +MODULE_AUTHOR("Matt Ranostay <mranostay@xxxxxxxxx>");
> +MODULE_DESCRIPTION("Sensirion SHT31 humidity and temperature sensor driver");
> +MODULE_LICENSE("GPL");
> --
> 2.7.4
>
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