drivers/iio/pressure/t5403.c

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