+
+struct ms5637_dev {
+ struct i2c_client *client;
+ struct mutex lock; /* Mutex protecting this data structure */
+ /* Added element for CRC computation */
+ u16 calibration_coeffs[MS5637_PROM_ELEMENTS_NB + 1];
+ unsigned long last_update;
+ int temperature;
+ unsigned int pressure;
+ u8 resolution_index;
+};
+
+static int ms5637_get_calibration_coeffs(struct ms5637_dev *dev_data,
+ u8 index, u16 *word)
+{
+ int ret;
+
+ ret = i2c_smbus_read_word_swapped(dev_data->client,
+ MS5637_PROM_READ + (index << 1));
+ if (ret < 0)
+ return ret;
+ *word = ret;
Blank line here.
+ return 0;
+}
+
+static bool ms5637_crc_check(u16 *n_prom, u8 crc)
+{
+ unsigned int cnt, n_bit;
+ u16 n_rem, crc_read;
+
+ n_rem = 0x0000;
+ crc_read = n_prom[0];
+ n_prom[MS5637_PROM_ELEMENTS_NB] = 0;
+ n_prom[0] &= 0x0FFF; /* Clear the CRC computation part */
+
+ 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;
blank line here.
+ return n_rem == crc;
+}
+
+static int ms5637_fill_calibration_coeffs(struct ms5637_dev *dev_data)
+{
+ int i, ret;
+
+ for (i = 0; i < MS5637_PROM_ELEMENTS_NB; i++) {
+ ret = ms5637_get_calibration_coeffs(
+ dev_data, 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;
+ }
+
+ dev_dbg(&dev_data->client->dev, "Coeff %d : %d", i,
+ dev_data->calibration_coeffs[i]);
+ }
+
+ if ( ms5637_crc_check(
+ dev_data->calibration_coeffs,
+ (dev_data->calibration_coeffs[0] & 0xF000) >> 12) == false) {
+ dev_err(&dev_data->client->dev,
+ "Calibration coefficients crc check error\n");
+ return -ENODEV;
+ }
+ return 0;
+}
+
+static int ms5637_read_adc_value(struct ms5637_dev *dev_data, u32 *adc_value)
+{
+ int ret
This is a fairly standard beast. I'd use a u32 and just set it to zero
before reading into the relevant address and using an endian conversion
to sort out the ordering if needed. That way if no endian conversion
is needed it is all free ;)
+ 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[2];
+
+ 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;
+ MS5637_CONVERSION_SLEEP(dev_data->resolution_index);
+
+ /* Retrieve ADC value */
+ ret = ms5637_read_adc_value(dev_data, t_adc);
+ if (ret < 0)
+ return ret;
+
+ /* 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;
+ MS5637_CONVERSION_SLEEP(dev_data->resolution_index);
+
+ /* Retrieve ADC value */
+ ret = ms5637_read_adc_value(dev_data, p_adc);
+ 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);
+
Why this throttle on frequency of reading? If there is a reason
add a comment saying why.
+ if (time_after(jiffies, dev_data->last_update + HZ / 2)) {
+ ret = ms5637_conversion_and_read_adc(dev_data, &t_adc, &p_adc);
+ if (ret < 0) {
+ 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);
+
+ dev_data->last_update = jiffies;
+ }
+ out:
+ mutex_unlock(&dev_data->lock);
+
+ return ret >= 0 ? 0 : ret;
I'd just make sure that ret is firmly defined to only be an error if
negative then just return it directly. (convention in the kernel is
for only negative errors).
+}
+
Again, this isn't complex enough or used enough to demand a utility function.
+static int ms5637_get_int_plus_micros_index(const int (*vals)[2], int n,
+ int val, int val2)
+{
+ while (n-- > 0)
+ if (val == vals[n][0] && val2 == vals[n][1])
+ return n;
+ return -EINVAL;
+}
+
Only used in one place. Roll this inline. It's not complex enough
that this little utilty function is needed.
+static int ms5637_get_samp_freq_index(struct ms5637_dev *dev_data,
+ int val, int val2)
+{
+ return ms5637_get_int_plus_micros_index(ms5637_samp_freq,
+ ARRAY_SIZE(ms5637_samp_freq), val, val2);
+}
+
+static ssize_t ms5637_show_int_plus_micros(char *buf,
+ const int (*vals)[2], int n)
+{
+ size_t len = 0;
+
+ while (n-- > 0)
+ len += scnprintf(buf + len, PAGE_SIZE - len,
+ "%d.%06d ", vals[n][0], vals[n][1]);
+
+ /* replace trailing space by newline */
+ buf[len - 1] = '\n';
+
+ return len;
+}
+
+static ssize_t ms5637_show_samp_freq_avail(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return ms5637_show_int_plus_micros(buf, ms5637_samp_freq,
+ ARRAY_SIZE(ms5637_samp_freq));
+}
+
+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:
+ ret = ms5637_read_temperature_and_pressure(dev_data);
+ if (ret)
+ goto err;
+ switch (channel->type) {
+ case IIO_TEMP: /* in °C */
+ *val = dev_data->temperature / 1000;
+ *val2 = (dev_data->temperature % 1000) * 1000;
+ break;
+ case IIO_PRESSURE: /* in kPa */
+ *val = dev_data->pressure / 1000;
+ *val2 = (dev_data->pressure % 1000) * 1000;
+ break;
+ default:
+ return -EINVAL;
+ }
+ break;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = ms5637_samp_freq[dev_data->resolution_index][0];
+ *val2 = ms5637_samp_freq[dev_data->resolution_index][1];
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return IIO_VAL_INT_PLUS_MICRO;
I'd return directly from the various case statements.
+ err:
+ dev_err(&indio_dev->dev, "Device read error\n");
You only get here from one place. Do this inline.
+ return ret;
+}
+
+static int ms5637_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct ms5637_dev *dev_data = iio_priv(indio_dev);
+ int i;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ i = ms5637_get_samp_freq_index(dev_data, val, val2);
+ if (i < 0)
+ return -EINVAL;
+
+ dev_data->resolution_index = i;
Nitpick of the day. A blank line here would be perfect ;)
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_chan_spec ms5637_channels[] = {
+ {
The indenting you are using here is somewhat unusual. Give the
entries another tab.
+ .type = IIO_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ },
+ {
+ .type = IIO_PRESSURE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ }
+};
+
+static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(ms5637_show_samp_freq_avail);
+
+static struct attribute *ms5637_attributes[] = {
+ &iio_dev_attr_sampling_frequency_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,
+ .write_raw = ms5637_write_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;
+
The func parameter passed into i2c_check_functionality is a bitmap so
do all these in one call.
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_WORD_DATA |
I2C_FUNC_SMBUS_WRITE_BYTE |
I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
etc.
+ 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;
+ dev_data->resolution_index = 5;
+ dev_data->last_update = jiffies - HZ / 2;
+ 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 = 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)
+ return ret;
+
+ ret = devm_iio_device_register(&client->dev, indio_dev);
+ if (ret < 0)
+ return ret;
+
+ dev_dbg(&client->dev, "Driver initialization done");
There are a lot of ways fo telling it is finsihed ;) I'd drop this
particular debug output from a driver just before submitting it.
+ return 0;
+}
+
+static const struct i2c_device_id ms5637_id[] = {
+ {"ms5637", 0},
+ {}
+};
+
+static struct i2c_driver ms5637_driver = {
+ .probe = ms5637_probe,
+ .id_table = ms5637_id,
+ .driver = {
+ .name = "ms5637",
+ .owner = THIS_MODULE,
+ },
+};
+
+module_i2c_driver(ms5637_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Measurement-Specialties ms5637 temperature & pressure driver");
+MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
+MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
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