Re: [PATCH] iio: (ms5637) Add Measurement Specialties MS5637 support

From: Daniel Baluta
Date: Thu Nov 06 2014 - 11:17:15 EST

Quick review:

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.

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 ++
> 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
> + *
> + * 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
> +
> +static const u16 conversion_time[] = { 1000, 2000, 3000, 5000, 9000, 17000 };
> +
> +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;
> + u16 n_rem, crc_read;
> +
> + n_rem = 0x00;
> + crc_read = n_prom[0];
> + n_prom[MS5637_PROM_ELEMENTS_NB] = 0;
> + n_prom[0] = (0x0FFF & (n_prom[0])); /* Clear the CRC byte */
> +
> + 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]);
> +
> + dev_dbg(&dev_data->client->dev, "Coeff %d : %d", i,
> + dev_data->calibration_coeffs[i]);
> +
> + if (ret < 0) {
> + dev_err(&dev_data->client->dev,
> + "unable to get calibration coefficients at address %d\n",
> + 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;
> + 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);
> +
> + 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 ÂC */
> + ret = ms5637_read_temperature_and_pressure(dev_data);
> + if (ret)
> + goto t_err;
> + *val = dev_data->temperature;
> + break;
> + case IIO_PRESSURE: /* in mB */
> + 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;
> + 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,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> + .scan_index = 0,
> + }
> +};
> +
> +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:
> + 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);
> + 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
> + 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
> +
> +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-ÂC value)
> +resolution_available - List of resolutions supported
> --
> 1.7.9.5
>
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