linux/drivers/iio/pressure/t5403.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * t5403.c - Support for EPCOS T5403 pressure/temperature sensor
   4 *
   5 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
   6 *
   7 * (7-bit I2C slave address 0x77)
   8 *
   9 * TODO: end-of-conversion irq
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/i2c.h>
  14#include <linux/iio/iio.h>
  15#include <linux/iio/sysfs.h>
  16#include <linux/delay.h>
  17
  18#define T5403_DATA 0xf5 /* data, LSB first, 16 bit */
  19#define T5403_CALIB_DATA 0x8e /* 10 calibration coeff., LSB first, 16 bit */
  20#define T5403_SLAVE_ADDR 0x88 /* I2C slave address, 0x77 */
  21#define T5403_COMMAND 0xf1
  22
  23/* command bits */
  24#define T5403_MODE_SHIFT 3 /* conversion time: 2, 8, 16, 66 ms */
  25#define T5403_PT BIT(1) /* 0 .. pressure, 1 .. temperature measurement */
  26#define T5403_SCO BIT(0) /* start conversion */
  27
  28#define T5403_MODE_LOW 0
  29#define T5403_MODE_STANDARD 1
  30#define T5403_MODE_HIGH 2
  31#define T5403_MODE_ULTRA_HIGH 3
  32
  33#define T5403_I2C_MASK (~BIT(7))
  34#define T5403_I2C_ADDR 0x77
  35
  36static const int t5403_pressure_conv_ms[] = {2, 8, 16, 66};
  37
  38struct t5403_data {
  39        struct i2c_client *client;
  40        struct mutex lock;
  41        int mode;
  42        __le16 c[10];
  43};
  44
  45#define T5403_C_U16(i) le16_to_cpu(data->c[(i) - 1])
  46#define T5403_C(i) sign_extend32(T5403_C_U16(i), 15)
  47
  48static int t5403_read(struct t5403_data *data, bool pressure)
  49{
  50        int wait_time = 3;  /* wakeup time in ms */
  51
  52        int ret = i2c_smbus_write_byte_data(data->client, T5403_COMMAND,
  53                (pressure ? (data->mode << T5403_MODE_SHIFT) : T5403_PT) |
  54                T5403_SCO);
  55        if (ret < 0)
  56                return ret;
  57
  58        wait_time += pressure ? t5403_pressure_conv_ms[data->mode] : 2;
  59
  60        msleep(wait_time);
  61
  62        return i2c_smbus_read_word_data(data->client, T5403_DATA);
  63}
  64
  65static int t5403_comp_pressure(struct t5403_data *data, int *val, int *val2)
  66{
  67        int ret;
  68        s16 t_r;
  69        u16 p_r;
  70        s32 S, O, X;
  71
  72        mutex_lock(&data->lock);
  73
  74        ret = t5403_read(data, false);
  75        if (ret < 0)
  76                goto done;
  77        t_r = ret;
  78
  79        ret = t5403_read(data, true);
  80        if (ret < 0)
  81                goto done;
  82        p_r = ret;
  83
  84        /* see EPCOS application note */
  85        S = T5403_C_U16(3) + (s32) T5403_C_U16(4) * t_r / 0x20000 +
  86                T5403_C(5) * t_r / 0x8000 * t_r / 0x80000 +
  87                T5403_C(9) * t_r / 0x8000 * t_r / 0x8000 * t_r / 0x10000;
  88
  89        O = T5403_C(6) * 0x4000 + T5403_C(7) * t_r / 8 +
  90                T5403_C(8) * t_r / 0x8000 * t_r / 16 +
  91                T5403_C(9) * t_r / 0x8000 * t_r / 0x10000 * t_r;
  92
  93        X = (S * p_r + O) / 0x4000;
  94
  95        X += ((X - 75000) * (X - 75000) / 0x10000 - 9537) *
  96            T5403_C(10) / 0x10000;
  97
  98        *val = X / 1000;
  99        *val2 = (X % 1000) * 1000;
 100
 101done:
 102        mutex_unlock(&data->lock);
 103        return ret;
 104}
 105
 106static int t5403_comp_temp(struct t5403_data *data, int *val)
 107{
 108        int ret;
 109        s16 t_r;
 110
 111        mutex_lock(&data->lock);
 112        ret = t5403_read(data, false);
 113        if (ret < 0)
 114                goto done;
 115        t_r = ret;
 116
 117        /* see EPCOS application note */
 118        *val = ((s32) T5403_C_U16(1) * t_r / 0x100 +
 119                (s32) T5403_C_U16(2) * 0x40) * 1000 / 0x10000;
 120
 121done:
 122        mutex_unlock(&data->lock);
 123        return ret;
 124}
 125
 126static int t5403_read_raw(struct iio_dev *indio_dev,
 127                          struct iio_chan_spec const *chan,
 128                          int *val, int *val2, long mask)
 129{
 130        struct t5403_data *data = iio_priv(indio_dev);
 131        int ret;
 132
 133        switch (mask) {
 134        case IIO_CHAN_INFO_PROCESSED:
 135                switch (chan->type) {
 136                case IIO_PRESSURE:
 137                        ret = t5403_comp_pressure(data, val, val2);
 138                        if (ret < 0)
 139                                return ret;
 140                        return IIO_VAL_INT_PLUS_MICRO;
 141                case IIO_TEMP:
 142                        ret = t5403_comp_temp(data, val);
 143                        if (ret < 0)
 144                                return ret;
 145                        return IIO_VAL_INT;
 146                default:
 147                        return -EINVAL;
 148            }
 149        case IIO_CHAN_INFO_INT_TIME:
 150                *val = 0;
 151                *val2 = t5403_pressure_conv_ms[data->mode] * 1000;
 152                return IIO_VAL_INT_PLUS_MICRO;
 153        default:
 154                return -EINVAL;
 155        }
 156}
 157
 158static int t5403_write_raw(struct iio_dev *indio_dev,
 159                           struct iio_chan_spec const *chan,
 160                           int val, int val2, long mask)
 161{
 162        struct t5403_data *data = iio_priv(indio_dev);
 163        int i;
 164
 165        switch (mask) {
 166        case IIO_CHAN_INFO_INT_TIME:
 167                if (val != 0)
 168                        return -EINVAL;
 169                for (i = 0; i < ARRAY_SIZE(t5403_pressure_conv_ms); i++)
 170                        if (val2 == t5403_pressure_conv_ms[i] * 1000) {
 171                                mutex_lock(&data->lock);
 172                                data->mode = i;
 173                                mutex_unlock(&data->lock);
 174                                return 0;
 175                        }
 176                return -EINVAL;
 177        default:
 178                return -EINVAL;
 179        }
 180}
 181
 182static const struct iio_chan_spec t5403_channels[] = {
 183        {
 184                .type = IIO_PRESSURE,
 185                .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 186                    BIT(IIO_CHAN_INFO_INT_TIME),
 187        },
 188        {
 189                .type = IIO_TEMP,
 190                .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
 191        },
 192};
 193
 194static IIO_CONST_ATTR_INT_TIME_AVAIL("0.002 0.008 0.016 0.066");
 195
 196static struct attribute *t5403_attributes[] = {
 197        &iio_const_attr_integration_time_available.dev_attr.attr,
 198        NULL
 199};
 200
 201static const struct attribute_group t5403_attribute_group = {
 202        .attrs = t5403_attributes,
 203};
 204
 205static const struct iio_info t5403_info = {
 206        .read_raw = &t5403_read_raw,
 207        .write_raw = &t5403_write_raw,
 208        .attrs = &t5403_attribute_group,
 209};
 210
 211static int t5403_probe(struct i2c_client *client,
 212                         const struct i2c_device_id *id)
 213{
 214        struct t5403_data *data;
 215        struct iio_dev *indio_dev;
 216        int ret;
 217
 218        if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA |
 219            I2C_FUNC_SMBUS_I2C_BLOCK))
 220                return -EOPNOTSUPP;
 221
 222        ret = i2c_smbus_read_byte_data(client, T5403_SLAVE_ADDR);
 223        if (ret < 0)
 224                return ret;
 225        if ((ret & T5403_I2C_MASK) != T5403_I2C_ADDR)
 226                return -ENODEV;
 227
 228        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 229        if (!indio_dev)
 230                return -ENOMEM;
 231
 232        data = iio_priv(indio_dev);
 233        data->client = client;
 234        mutex_init(&data->lock);
 235
 236        i2c_set_clientdata(client, indio_dev);
 237        indio_dev->info = &t5403_info;
 238        indio_dev->name = id->name;
 239        indio_dev->dev.parent = &client->dev;
 240        indio_dev->modes = INDIO_DIRECT_MODE;
 241        indio_dev->channels = t5403_channels;
 242        indio_dev->num_channels = ARRAY_SIZE(t5403_channels);
 243
 244        data->mode = T5403_MODE_STANDARD;
 245
 246        ret = i2c_smbus_read_i2c_block_data(data->client, T5403_CALIB_DATA,
 247            sizeof(data->c), (u8 *) data->c);
 248        if (ret < 0)
 249                return ret;
 250
 251        return devm_iio_device_register(&client->dev, indio_dev);
 252}
 253
 254static const struct i2c_device_id t5403_id[] = {
 255        { "t5403", 0 },
 256        { }
 257};
 258MODULE_DEVICE_TABLE(i2c, t5403_id);
 259
 260static struct i2c_driver t5403_driver = {
 261        .driver = {
 262                .name   = "t5403",
 263        },
 264        .probe = t5403_probe,
 265        .id_table = t5403_id,
 266};
 267module_i2c_driver(t5403_driver);
 268
 269MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 270MODULE_DESCRIPTION("EPCOS T5403 pressure/temperature sensor driver");
 271MODULE_LICENSE("GPL");
 272