Re: [PATCH] iio: (ms5637) Add Measurement Specialties MS5637 support
From: Hartmut Knaack
Date: Thu Nov 06 2014 - 17:53:50 EST
Peter Meerwald schrieb am 06.11.2014 17:54:
>> Use iio: ms5637: Add Measurement Specialties MS5637 support instead of
>> iio: (ms5637) Add Measurement Specialties MS5637 support for subject.
>>
>> If available please add a link to the datasheet here.
>
> some more comments below...
Just one comment for now.
>
>> On Thu, Nov 6, 2014 at 11:46 AM, Markezana, William
>> <William.Markezana@xxxxxxxxxxxxx> wrote:
>>> Signed-off-by: Ludovic <ludovic.tancerel@xxxxxxxxxxxxxxxxx>
>>> ---
>>> drivers/iio/pressure/Kconfig | 10 +
>>> drivers/iio/pressure/Makefile | 1 +
>>> drivers/iio/pressure/ms5637.c | 488 +++++++++++++++++++++
>>> drivers/staging/iio/Documentation/pressure/ms5637 | 25 ++
>
> don't add documentation to staging
>
>>> 4 files changed, 524 insertions(+)
>>> create mode 100644 drivers/iio/pressure/ms5637.c
>>> create mode 100644 drivers/staging/iio/Documentation/pressure/ms5637
>>>
>>> diff --git a/drivers/iio/pressure/Kconfig b/drivers/iio/pressure/Kconfig
>>> index ffac8ac..4ba9bd5 100644
>>> --- a/drivers/iio/pressure/Kconfig
>>> +++ b/drivers/iio/pressure/Kconfig
>>> @@ -41,6 +41,16 @@ config MPL3115
>>> To compile this driver as a module, choose M here: the module
>>> will be called mpl3115.
>>>
>>> +config MS5637
>>> + tristate "MS5637 pressure & temperature sensor"
>>> + depends on I2C
>>> + help
>>> + If you say yes here you get support for the Measurement Specialties
>>> + MS5637 pressure and temperature sensor.
>>> +
>>> + This driver can also be built as a module. If so, the module will
>>> + be called ms5637.
>>> +
>>> config IIO_ST_PRESS
>>> tristate "STMicroelectronics pressure sensor Driver"
>>> depends on (I2C || SPI_MASTER) && SYSFS
>>> diff --git a/drivers/iio/pressure/Makefile b/drivers/iio/pressure/Makefile
>>> index c53d250..50fe66e 100644
>>> --- a/drivers/iio/pressure/Makefile
>>> +++ b/drivers/iio/pressure/Makefile
>>> @@ -6,6 +6,7 @@
>>> obj-$(CONFIG_HID_SENSOR_PRESS) += hid-sensor-press.o
>>> obj-$(CONFIG_MPL115) += mpl115.o
>>> obj-$(CONFIG_MPL3115) += mpl3115.o
>>> +obj-$(CONFIG_MS5637) += ms5637.o
>>> obj-$(CONFIG_IIO_ST_PRESS) += st_pressure.o
>>> st_pressure-y := st_pressure_core.o
>>> st_pressure-$(CONFIG_IIO_BUFFER) += st_pressure_buffer.o
>>> diff --git a/drivers/iio/pressure/ms5637.c b/drivers/iio/pressure/ms5637.c
>>> new file mode 100644
>>> index 0000000..ea74636
>>> --- /dev/null
>>> +++ b/drivers/iio/pressure/ms5637.c
>>> @@ -0,0 +1,488 @@
>>> +/*
>>> + * ms5637.c - Support for Measurement Specialties MS5637 temperature sensor
>
> pressure & temperature
>
>>> + *
>>> + * Copyright (c) 2014 Measurement Specialties
>>> + *
>>> + * Licensed under the GPL-2.
>>> + *
>>> + * (7-bit I2C slave address 0x77)
>>> + *
>>> + */
>>> +
>>> +#include <linux/init.h>
>>> +#include <linux/device.h>
>>> +#include <linux/kernel.h>
>>> +#include <linux/stat.h>
>>> +#include <linux/module.h>
>>> +#include <linux/i2c.h>
>>> +#include <linux/iio/iio.h>
>>> +#include <linux/iio/sysfs.h>
>>> +#include <linux/jiffies.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/mutex.h>
>>> +
>>> +/* MS5637 Commands */
>>> +#define MS5637_RESET (0x1E)
>>> +#define MS5637_TEMPERATURE_CONVERSION_START (0x50)
>>> +#define MS5637_PRESSURE_CONVERSION_START (0x40)
>>> +#define MS5637_ADC_READ (0x00)
>>> +#define MS5637_PROM_READ (0xA0)
>>> +#define MS5637_PROM_ELEMENTS_NB (7)
>>
>> I would prefer to remove "()" around hexa/decimal values.
>>
>>> +
>>> +#define ATTR_RESET 0
>>> +#define ATTR_RESOLUTION 1
>
> MS5637_ prefix please
>
>>> +
>>> +static const u16 conversion_time[] = { 1000, 2000, 3000, 5000, 9000, 17000 };
>
> ms5637_ prefix please
>
>>> +
>>> +struct ms5637_dev {
>>> + struct i2c_client *client;
>>> + struct mutex lock; /* mutex protecting this data structure */
>>> + u16 calibration_coeffs[MS5637_PROM_ELEMENTS_NB];
>>> + bool got_calibration_words;
>>> + unsigned long last_update;
>>> + bool valid;
>>> + int temperature;
>>> + unsigned int pressure;
>>> + u8 resolution_index;
>>> +};
>>> +
>>> +static int ms5637_get_calibration_coeffs(struct ms5637_dev *dev_data,
>>> + unsigned char index, u16 *word)
>>> +{
>>> + int ret = 0;
>>> +
>>> + ret = i2c_smbus_read_word_swapped(dev_data->client,
>>> + MS5637_PROM_READ + (index << 1));
>>> + if (ret < 0)
>>> + return ret;
>>> + *word = (u16) ret & 0xFFFF;
>>> + return 0;
>>> +}
>>> +
>>> +static bool ms5637_crc_check(u16 *n_prom, u8 crc)
>>> +{
>>> + u8 cnt, n_bit;
>
> cnt should be unsigned int, it's just a counter should have the CPUs
> native size
>
>>> + u16 n_rem, crc_read;
>>> +
>>> + n_rem = 0x00;
>
> should be 0 or 0x0000 as n_rem is u16
>
>>> + crc_read = n_prom[0];
>>> + n_prom[MS5637_PROM_ELEMENTS_NB] = 0;
>>> + n_prom[0] = (0x0FFF & (n_prom[0])); /* Clear the CRC byte */
>
> remove extra parenthesis
Actually, it should be as simple as this:
n_prom[0] &= 0x0FFF;
>
>>> +
>>> + for (cnt = 0; cnt < (MS5637_PROM_ELEMENTS_NB + 1) * 2; cnt++) {
>>> + if (cnt % 2 == 1)
>>> + n_rem ^= n_prom[cnt >> 1] & 0x00FF;
>>> + else
>>> + n_rem ^= n_prom[cnt >> 1] >> 8;
>>> +
>>> + for (n_bit = 8; n_bit > 0; n_bit--) {
>>> + if (n_rem & 0x8000)
>>> + n_rem = (n_rem << 1) ^ 0x3000;
>>> + else
>>> + n_rem <<= 1;
>>> + }
>>> + }
>>> + n_rem >>= 12;
>>> + n_prom[0] = crc_read;
>>> + return (n_rem == crc);
>>> +}
>>> +
>>> +static int ms5637_fill_calibration_coeffs(struct ms5637_dev *dev_data)
>>> +{
>>> + int i, ret = 0;
>>> +
>>> + for (i = 0; i < MS5637_PROM_ELEMENTS_NB; i++) {
>>> + ret = ms5637_get_calibration_coeffs(dev_data, i,
>>> + &dev_data->calibration_coeffs
>>> + [i]);
>
> linebreak looks weird before [i]
>
>>> +
>>> + dev_dbg(&dev_data->client->dev, "Coeff %d : %d", i,
>>> + dev_data->calibration_coeffs[i]);
>
> debug output should be after validity check
>
>>> +
>>> + if (ret < 0) {
>>> + dev_err(&dev_data->client->dev,
>>> + "unable to get calibration coefficients at address %d\n",
>
> Unable probably (uppercase all all other messages
>
>>> + i + 1);
>>> + return ret;
>>> + }
>>> + }
>>> +
>>> + if (!ms5637_crc_check(dev_data->calibration_coeffs,
>>> + (dev_data->
>>> + calibration_coeffs[0] & 0xF000) >> 12)) {
>>> + dev_err(&dev_data->client->dev,
>>> + "Calibration coefficients crc check error\n");
>>> + return -1;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int ms5637_read_adc_value(struct ms5637_dev *dev_data, u32 *adc_value)
>>> +{
>>> + int ret = 0;
>
> no need to initialize ret
>
>>> + u8 buf[3];
>>> +
>>> + ret =
>>> + i2c_smbus_read_i2c_block_data(dev_data->client, MS5637_ADC_READ, 3,
>>> + buf);
>>> + if (ret < 0)
>>> + return ret;
>>> + dev_dbg(&dev_data->client->dev, "ADC raw value : %x %x %x\n", buf[0],
>>> + buf[1], buf[2]);
>>> + *adc_value = (buf[0] << 16) + (buf[1] << 8) + buf[0];
>>> + return 0;
>>> +}
>>> +
>>> +static int ms5637_conversion_and_read_adc(struct ms5637_dev *dev_data,
>>> + u32 *t_adc, u32 *p_adc)
>>> +{
>>> + int ret;
>>> +
>>> + /* Trigger Temperature conversion */
>>> + ret = i2c_smbus_write_byte(dev_data->client,
>>> + MS5637_TEMPERATURE_CONVERSION_START
>>> + + dev_data->resolution_index * 2);
>>> + if (ret < 0)
>>> + return ret;
>>> + usleep_range(conversion_time[dev_data->resolution_index],
>>> + conversion_time[dev_data->resolution_index]+3000);
>>> + /* Retrieve ADC value */
>>> + ret = ms5637_read_adc_value(dev_data, t_adc);
>>> +
>> No check for ret here? If this is not needed then you can remove
>> the above assignment.
>>
>>> + /* Trigger Pressure conversion */
>>> + ret = i2c_smbus_write_byte(dev_data->client,
>>> + MS5637_PRESSURE_CONVERSION_START
>>> + + dev_data->resolution_index * 2);
>>> + if (ret < 0)
>>> + return ret;
>>> + usleep_range(conversion_time[dev_data->resolution_index],
>>> + conversion_time[dev_data->resolution_index]+3000);
>>> + /* Retrieve ADC value */
>>> + ret = ms5637_read_adc_value(dev_data, p_adc);
>>> +
>> No new line here.
>>> + if (ret < 0)
>>> + return ret;
>>> + return 0;
>>> +}
>>> +
>>> +static int ms5637_read_temperature_and_pressure(struct ms5637_dev *dev_data)
>>> +{
>>> + int ret = 0;
>>> + u32 t_adc, p_adc;
>>> + s32 dt, temp;
>>> + s64 off, sens, t2, off2, sens2;
>>> +
>>> + mutex_lock(&dev_data->lock);
>>> +
>>> + if (time_after(jiffies, dev_data->last_update + HZ / 2) ||
>>> + !dev_data->valid) {
>>> + if (!dev_data->got_calibration_words) {
>>> + ret = ms5637_fill_calibration_coeffs(dev_data);
>>> + if (ret < 0)
>>> + goto out;
>>> +
>>> + dev_data->got_calibration_words = true;
>>> + }
>>> +
>>> + ret = ms5637_conversion_and_read_adc(dev_data, &t_adc, &p_adc);
>>> +
> remove blank line
>
>>> + if (ret < 0) {
>>> + dev_data->got_calibration_words = false;
>>> + dev_err(&dev_data->client->dev,
>>> + "unable to make sensor adc conversion\n");
>>> + goto out;
>>> + }
>>> +
>>> + dt = (s32) t_adc - (dev_data->calibration_coeffs[5] << 8);
>>> +
>>> + /* Actual temperature = 2000 + dT * TEMPSENS */
>>> + temp =
>>> + 2000 + (((s64) dt * dev_data->calibration_coeffs[6]) >> 23);
>>> +
>>> + /* Second order temperature compensation */
>>> + if (temp < 2000) {
>>> + s64 tmp = (s64) temp - 2000;
>>> +
>>> + t2 = (3 * ((s64) dt * (s64) dt)) >> 33;
>>> + off2 = (61 * tmp * tmp) >> 4;
>>> + sens2 = (29 * tmp * tmp) >> 4;
>>> +
>>> + if (temp < -1500) {
>>> + s64 tmp = (s64) temp + 1500;
>>> +
>>> + off2 += 17 * tmp * tmp;
>>> + sens2 += 9 * tmp * tmp;
>>> + }
>>> + } else {
>>> + t2 = (5 * ((s64) dt * (s64) dt)) >> 38;
>>> + off2 = 0;
>>> + sens2 = 0;
>>> + }
>>> +
>>> + /* OFF = OFF_T1 + TCO * dT */
>>> + off = (((s64) dev_data->calibration_coeffs[2]) << 17)
>>> + +
>>> + ((((s64) dev_data->calibration_coeffs[4]) * (s64) dt) >> 6);
>>> + off -= off2;
>>> +
>>> + /* Sensitivity at actual temperature = SENS_T1 + TCS * dT */
>>> + sens = (((s64) dev_data->calibration_coeffs[1]) << 16)
>>> + + (((s64) dev_data->calibration_coeffs[3] * dt) >> 7);
>>> + sens -= sens2;
>>> +
>>> + /* Temperature compensated pressure = D1 * SENS - OFF */
>>> + dev_data->temperature = (temp - t2) * 10;
>>> + dev_data->pressure = (u32) (((((s64) p_adc * sens) >> 21)
>>> + - off) >> 15) / 100;
>>> +
>>> + dev_data->last_update = jiffies;
>>> + dev_data->valid = true;
>>> + }
>>> + out:
>>> + mutex_unlock(&dev_data->lock);
>>> +
>>> + return ret >= 0 ? 0 : ret;
>>> +}
>>> +
>>> +static int ms5637_read_raw(struct iio_dev *indio_dev,
>>> + struct iio_chan_spec const *channel, int *val,
>>> + int *val2, long mask)
>>> +{
>>> + int ret;
>>> + struct ms5637_dev *dev_data = iio_priv(indio_dev);
>>> +
>>> + switch (mask) {
>>> + case IIO_CHAN_INFO_PROCESSED:
>>> + switch (channel->type) {
>>> + case IIO_TEMP: /* in 0.001 °C */
>>> + ret = ms5637_read_temperature_and_pressure(dev_data);
>>> + if (ret)
>>> + goto t_err;
>>> + *val = dev_data->temperature;
>>> + break;
>>> + case IIO_PRESSURE: /* in mB */
>
> IIO wants kilopoascal
>
>>> + ret = ms5637_read_temperature_and_pressure(dev_data);
>>> + if (ret)
>>> + goto p_err;
>>> + *val = dev_data->pressure;
>>> + break;
>>> + default:
>>> + return -EINVAL;
>>> + }
>>> + ret = IIO_VAL_INT;
>>> + break;
>>> + default:
>>> + return -EINVAL;
>>> + }
>>> +
>>> + return ret;
>
> should simplify control flow a bit, just return instead of breaking,
> jumping
>
> is it really necesary to have two different error messages?
> could just code the call to ms5637_read_temperature_and_pressure() once
>
>>> + t_err:
>>> + dev_err(&indio_dev->dev, "Temperature read error\n");
>>> + return ret;
>>> + p_err:
>>> + dev_err(&indio_dev->dev, "Pressure read error\n");
>>> + return ret;
>>> +}
>>> +
>>> +static const struct iio_chan_spec ms5637_channels[] = {
>>> + {
>>> + .type = IIO_TEMP,
>>> + .output = 1,
>>> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
>>> + .scan_index = 0,
>>> + },
>>> + {
>>> + .type = IIO_PRESSURE,
>>> + .output = 1,
>
> output is for output channels, I guess the ms5637 cannot change the
> weather :)
>
>>> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
>>> + .scan_index = 0,
>
> no need set the scan_index
>
>>> + }
>>> +};
>>> +
>>> +static ssize_t ms5637_read_attr(struct device *dev,
>>> + struct device_attribute *attr, char *buf)
>>> +{
>>> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>>> + struct ms5637_dev *dev_data = iio_priv(indio_dev);
>>> + struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
>>> + int ret = 0;
>>> +
>>> + switch (this_attr->address) {
>>> + case ATTR_RESET:
>>> + ret = sprintf(buf, "0\n");
>>> + break;
>>> + case ATTR_RESOLUTION:
>
> uhuh, private ABI
> maybe this could be modelled by IIO's integration time?
>
>>> + ret = sprintf(buf, "%d\n", dev_data->resolution_index + 8);
>>> + break;
>>> + default:
>>> + return -EINVAL;
>>> + }
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static ssize_t ms5637_write_attr(struct device *dev,
>>> + struct device_attribute *attr,
>>> + const char *buf, size_t len)
>>> +{
>>> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>>> + struct ms5637_dev *dev_data = iio_priv(indio_dev);
>>> + struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
>>> + u8 val;
>>> + int ret;
>>> +
>>> + ret = kstrtou8(buf, 10, &val);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + mutex_lock(&dev_data->lock);
>>> + switch (this_attr->address) {
>>> + case ATTR_RESET:
>>> + if (val != 1)
>>> + goto einval;
>>> +
>>> + ret = i2c_smbus_write_byte(dev_data->client, MS5637_RESET);
>>> + if (ret < 0)
>>> + goto out;
>>> + usleep_range(3000, 6000);
>>> +
>>> + break;
>>> + case ATTR_RESOLUTION:
>>> + if ((val < 8) || (val > 13))
>>> + goto einval;
>>> + dev_data->resolution_index = val - 8;
>>> + break;
>>> + default:
>>> + goto einval;
>>> + }
>>> +
>>> + dev_data->valid = false;
>>> + goto out;
>>> + einval:
>>> + ret = -EINVAL;
>>> + out:
>>> + mutex_unlock(&dev_data->lock);
>>> +
>>> + return ret ? ret : len;
>>> +}
>>> +
>>> +static IIO_DEVICE_ATTR(in_reset,
>>> + S_IRUGO | S_IWUSR,
>>> + ms5637_read_attr, ms5637_write_attr, ATTR_RESET);
>>> +static IIO_DEVICE_ATTR(in_resolution,
>>> + S_IRUGO | S_IWUSR,
>>> + ms5637_read_attr, ms5637_write_attr, ATTR_RESOLUTION);
>>> +static IIO_CONST_ATTR(resolution_available, "8 9 10 11 12 13");
>>> +
>>> +static struct attribute *ms5637_attributes[] = {
>>> + &iio_dev_attr_in_reset.dev_attr.attr,
>>> + &iio_dev_attr_in_resolution.dev_attr.attr,
>>> + &iio_const_attr_resolution_available.dev_attr.attr,
>>> + NULL,
>>> +};
>>> +
>>> +static const struct attribute_group ms5637_attribute_group = {
>>> + .attrs = ms5637_attributes,
>>> +};
>>> +
>>> +static const struct iio_info ms5637_info = {
>>> + .read_raw = ms5637_read_raw,
>>> + .attrs = &ms5637_attribute_group,
>>> + .driver_module = THIS_MODULE,
>>> +};
>>> +
>>> +static int ms5637_probe(struct i2c_client *client,
>>> + const struct i2c_device_id *id)
>>> +{
>>> + struct ms5637_dev *dev_data;
>>> + struct iio_dev *indio_dev;
>>> + int ret;
>>> +
>>> + if (!i2c_check_functionality(client->adapter,
>>> + I2C_FUNC_SMBUS_READ_WORD_DATA)) {
>>> + dev_err(&client->dev,
>>> + "adapter does not support SMBus read word transactions\n");
>>> + return -ENODEV;
>>> + }
>>> +
>>> + if (!i2c_check_functionality(client->adapter,
>>> + I2C_FUNC_SMBUS_WRITE_BYTE)) {
>>> + dev_err(&client->dev,
>>> + "adapter does not support SMBus write byte transactions\n");
>>> + return -ENODEV;
>>> + }
>>> +
>>> + if (!i2c_check_functionality(client->adapter,
>>> + I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
>>> + dev_err(&client->dev,
>>> + "adapter does not support SMBus read block transactions\n");
>>> + return -ENODEV;
>>> + }
>>> +
>>> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
>>> + if (!indio_dev)
>>> + return -ENOMEM;
>>> +
>>> + dev_data = iio_priv(indio_dev);
>>> + dev_data->client = client;
>>> + mutex_init(&dev_data->lock);
>>> +
>>> + indio_dev->info = &ms5637_info;
>>> + indio_dev->name = id->name;
>>> + indio_dev->dev.parent = &client->dev;
>>> + indio_dev->modes = INDIO_DIRECT_MODE;
>>> + indio_dev->channels = ms5637_channels;
>>> + indio_dev->num_channels = ARRAY_SIZE(ms5637_channels);
>>> +
>>> + i2c_set_clientdata(client, indio_dev);
>>> + ret = iio_device_register(indio_dev);
>>> + if (ret < 0)
>>> + return ret;
>>> +
>>> + ret = i2c_smbus_write_byte(client, MS5637_RESET);
>
> I'd rather do this before iio_device_register() -- what happens when it
> fails? there is no unregister()
>
>>> + if (ret < 0)
>>> + return ret;
>>> + usleep_range(3000, 6000);
>>> +
>>> + ret = ms5637_fill_calibration_coeffs(dev_data);
>>> + if (ret == 0)
>>> + dev_data->got_calibration_words = true;
>>> +
>>> + if (ret < 0)
>>> + return ret;
>>> +
>>> + dev_dbg(&client->dev, "Driver initialization done");
>>> + return 0;
>>> +}
>>> +
>>> +static int ms5637_remove(struct i2c_client *client)
>>> +{
>>> + struct iio_dev *indio_dev = i2c_get_clientdata(client);
>>> +
>>> + iio_device_unregister(indio_dev);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static const struct i2c_device_id ms5637_id[] = {
>>> + {"ms5637", 0},
>>> + {}
>>> +};
>>> +
>>> +static struct i2c_driver ms5637_driver = {
>>> + .probe = ms5637_probe,
>>> + .remove = ms5637_remove,
>>> + .id_table = ms5637_id,
>>> + .driver = {
>>> + .name = "ms5637",
>>> + .owner = THIS_MODULE,
>>> + },
>>> +};
>>> +
>>> +module_i2c_driver(ms5637_driver);
>>> +
>>> +MODULE_LICENSE("GPL");
>>> +MODULE_DESCRIPTION("Measurement Specialties MS5637 temperature driver");
>>> +MODULE_AUTHOR("William Markezana <william.markezana@xxxxxxxxxxxxx>");
>>> +MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@xxxxxxxxxxxxxxxxx>");
>>> diff --git a/drivers/staging/iio/Documentation/pressure/ms5637 b/drivers/staging/iio/Documentation/pressure/ms5637
>>> new file mode 100644
>>> index 0000000..d0d64f3
>>> --- /dev/null
>>> +++ b/drivers/staging/iio/Documentation/pressure/ms5637
>>> @@ -0,0 +1,25 @@
>>> +Kernel driver ms5637
>>> +====================
>>> +
>>> +Supported chips:
>>> + * Measurement Specialties MS5637
>>> + Prefix: 'ms5637'
>>> + Addresses scanned: I2C 0x76
>
> 0x77 is claimed at the top of ms5637.c
>
>>> + Datasheet: Available for download on meas-spec.com
>>> +
>>> +Authors:
>>> + William Markezana (Meas-Spec) <william.markezana@xxxxxxxxxxxxx>
>>> + Ludovic Tancerel <ludovic.tancerel@xxxxxxxxxxxxxxxxx>
>>> +
>>> +Description
>>> +-----------
>>> +
>>> +The MS5637 is a single chip pressure & temperature sensor.
>>> +The driver returns a milli-bar pressure value and a milli-degre celius value using the iio framework
>
> degree; the information so far is redundant
>
>>> +
>>> +Via the iio sysfs interface, there are several attributes available.
>>> +in_reset - Reset ms5637 device by writing a 1 in it.
>>> +in_resolution - Set the number of bits for ADC resolution.
>>> +out_pressure_input - Current pressure from ms5637 sensor (milli-bar)
>>> +out_temp_input - Current temperature from htu21 sensor (milli-°C value)
>>> +resolution_available - List of resolutions supported
>
> in_, not out_
>
> regular IIO channels (integration time?) could/should be used
>
> I don't know about reset, needed?
>
> private ABI should go to documentation/ABI/testing/sysfs-bus-iio-*
>
>>> --
>>> 1.7.9.5
>>>
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