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Release 4.7 drivers/iio/temperature/tsys01.c

/*
 * 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; }

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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; } }

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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); }

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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; }

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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); }

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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 -EOPNOTSUPP; } 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); }

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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");

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