diff options
Diffstat (limited to 'drivers/iio/temperature/tsys01.c')
| -rw-r--r-- | drivers/iio/temperature/tsys01.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/drivers/iio/temperature/tsys01.c b/drivers/iio/temperature/tsys01.c new file mode 100644 index 000000000000..05c12060ce8d --- /dev/null +++ b/drivers/iio/temperature/tsys01.c @@ -0,0 +1,230 @@ +/* + * tsys01.c - Support for Measurement-Specialties tsys01 temperature sensor + * + * Copyright (c) 2015 Measurement-Specialties + * + * Licensed under the GPL-2. + * + * Datasheet: + * http://www.meas-spec.com/downloads/TSYS01_Digital_Temperature_Sensor.pdf + */ + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/device.h> +#include <linux/mutex.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/stat.h> +#include "../common/ms_sensors/ms_sensors_i2c.h" + +/* TSYS01 Commands */ +#define TSYS01_RESET 0x1E +#define TSYS01_CONVERSION_START 0x48 +#define TSYS01_ADC_READ 0x00 +#define TSYS01_PROM_READ 0xA0 + +#define TSYS01_PROM_WORDS_NB 8 + +struct tsys01_dev { + void *client; + struct mutex lock; /* lock during conversion */ + + int (*reset)(void *cli, u8 cmd, unsigned int delay); + int (*convert_and_read)(void *cli, u8 conv, u8 rd, + unsigned int delay, u32 *adc); + int (*read_prom_word)(void *cli, int cmd, u16 *word); + + u16 prom[TSYS01_PROM_WORDS_NB]; +}; + +/* Multiplication coefficients for temperature computation */ +static const int coeff_mul[] = { -1500000, 1000000, -2000000, + 4000000, -2000000 }; + +static int tsys01_read_temperature(struct iio_dev *indio_dev, + s32 *temperature) +{ + int ret, i; + u32 adc; + s64 temp = 0; + struct tsys01_dev *dev_data = iio_priv(indio_dev); + + mutex_lock(&dev_data->lock); + ret = dev_data->convert_and_read(dev_data->client, + TSYS01_CONVERSION_START, + TSYS01_ADC_READ, 9000, &adc); + mutex_unlock(&dev_data->lock); + if (ret) + return ret; + + adc >>= 8; + + /* Temperature algorithm */ + for (i = 4; i > 0; i--) { + temp += coeff_mul[i] * + (s64)dev_data->prom[5 - i]; + temp *= (s64)adc; + temp = div64_s64(temp, 100000); + } + temp *= 10; + temp += coeff_mul[0] * (s64)dev_data->prom[5]; + temp = div64_s64(temp, 100000); + + *temperature = temp; + + return 0; +} + +static int tsys01_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *channel, int *val, + int *val2, long mask) +{ + int ret; + s32 temperature; + + switch (mask) { + case IIO_CHAN_INFO_PROCESSED: + switch (channel->type) { + case IIO_TEMP: /* in milli °C */ + ret = tsys01_read_temperature(indio_dev, &temperature); + if (ret) + return ret; + *val = temperature; + + return IIO_VAL_INT; + default: + return -EINVAL; + } + default: + return -EINVAL; + } +} + +static const struct iio_chan_spec tsys01_channels[] = { + { + .type = IIO_TEMP, + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED), + } +}; + +static const struct iio_info tsys01_info = { + .read_raw = tsys01_read_raw, + .driver_module = THIS_MODULE, +}; + +static bool tsys01_crc_valid(u16 *n_prom) +{ + u8 cnt; + u8 sum = 0; + + for (cnt = 0; cnt < TSYS01_PROM_WORDS_NB; cnt++) + sum += ((n_prom[0] >> 8) + (n_prom[0] & 0xFF)); + + return (sum == 0); +} + +static int tsys01_read_prom(struct iio_dev *indio_dev) +{ + int i, ret; + struct tsys01_dev *dev_data = iio_priv(indio_dev); + char buf[7 * TSYS01_PROM_WORDS_NB + 1]; + char *ptr = buf; + + for (i = 0; i < TSYS01_PROM_WORDS_NB; i++) { + ret = dev_data->read_prom_word(dev_data->client, + TSYS01_PROM_READ + (i << 1), + &dev_data->prom[i]); + if (ret) + return ret; + + ret = sprintf(ptr, "0x%04x ", dev_data->prom[i]); + ptr += ret; + } + + if (!tsys01_crc_valid(dev_data->prom)) { + dev_err(&indio_dev->dev, "prom crc check error\n"); + return -ENODEV; + } + *ptr = 0; + dev_info(&indio_dev->dev, "PROM coefficients : %s\n", buf); + + return 0; +} + +static int tsys01_probe(struct iio_dev *indio_dev, struct device *dev) +{ + int ret; + struct tsys01_dev *dev_data = iio_priv(indio_dev); + + mutex_init(&dev_data->lock); + + indio_dev->info = &tsys01_info; + indio_dev->name = dev->driver->name; + indio_dev->dev.parent = dev; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = tsys01_channels; + indio_dev->num_channels = ARRAY_SIZE(tsys01_channels); + + ret = dev_data->reset(dev_data->client, TSYS01_RESET, 3000); + if (ret) + return ret; + + ret = tsys01_read_prom(indio_dev); + if (ret) + return ret; + + return devm_iio_device_register(dev, indio_dev); +} + +static int tsys01_i2c_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct tsys01_dev *dev_data; + struct iio_dev *indio_dev; + + if (!i2c_check_functionality(client->adapter, + I2C_FUNC_SMBUS_WORD_DATA | + I2C_FUNC_SMBUS_WRITE_BYTE | + I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { + dev_err(&client->dev, + "Adapter does not support some i2c transaction\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->reset = ms_sensors_reset; + dev_data->read_prom_word = ms_sensors_read_prom_word; + dev_data->convert_and_read = ms_sensors_convert_and_read; + + i2c_set_clientdata(client, indio_dev); + + return tsys01_probe(indio_dev, &client->dev); +} + +static const struct i2c_device_id tsys01_id[] = { + {"tsys01", 0}, + {} +}; +MODULE_DEVICE_TABLE(i2c, tsys01_id); + +static struct i2c_driver tsys01_driver = { + .probe = tsys01_i2c_probe, + .id_table = tsys01_id, + .driver = { + .name = "tsys01", + }, +}; + +module_i2c_driver(tsys01_driver); + +MODULE_DESCRIPTION("Measurement-Specialties tsys01 temperature driver"); +MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>"); +MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>"); +MODULE_LICENSE("GPL v2"); |