drivers/iio/pressure/mpl3115.c

   1 /*
   2  * mpl3115.c - Support for Freescale MPL3115A2 pressure/temperature sensor
   3  *
   4  * Copyright (c) 2013 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 0x60)
  11  *
  12  * TODO: FIFO buffer, altimeter mode, oversampling, continuous mode,
  13  * interrupts, user offset correction, raw mode
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/i2c.h>
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/sysfs.h>
  20 #include <linux/iio/trigger_consumer.h>
  21 #include <linux/iio/buffer.h>
  22 #include <linux/iio/triggered_buffer.h>
  23 #include <linux/delay.h>
  24
  25 #define MPL3115_STATUS 0x00
  26 #define MPL3115_OUT_PRESS 0x01 /* MSB first, 20 bit */
  27 #define MPL3115_OUT_TEMP 0x04 /* MSB first, 12 bit */
  28 #define MPL3115_WHO_AM_I 0x0c
  29 #define MPL3115_CTRL_REG1 0x26
  30
  31 #define MPL3115_DEVICE_ID 0xc4
  32
  33 #define MPL3115_STATUS_PRESS_RDY BIT(2)
  34 #define MPL3115_STATUS_TEMP_RDY BIT(1)
  35
  36 #define MPL3115_CTRL_RESET BIT(2) /* software reset */
  37 #define MPL3115_CTRL_OST BIT(1) /* initiate measurement */
  38 #define MPL3115_CTRL_ACTIVE BIT(0) /* continuous measurement */
  39 #define MPL3115_CTRL_OS_258MS (BIT(5) | BIT(4)) /* 64x oversampling */
  40
  41 struct mpl3115_data {
  42         struct i2c_client *client;
  43         struct mutex lock;
  44         u8 ctrl_reg1;
  45 };
  46
  47 static int mpl3115_request(struct mpl3115_data *data)
  48 {
  49         int ret, tries = 15;
  50
  51         /* trigger measurement */
  52         ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
  53                 data->ctrl_reg1 | MPL3115_CTRL_OST);
  54         if (ret < 0)
  55                 return ret;
  56
  57         while (tries-- > 0) {
  58                 ret = i2c_smbus_read_byte_data(data->client, MPL3115_CTRL_REG1);
  59                 if (ret < 0)
  60                         return ret;
  61                 /* wait for data ready, i.e. OST cleared */
  62                 if (!(ret & MPL3115_CTRL_OST))
  63                         break;
  64                 msleep(20);
  65         }
  66
  67         if (tries < 0) {
  68                 dev_err(&data->client->dev, "data not ready\n");
  69                 return -EIO;
  70         }
  71
  72         return 0;
  73 }
  74
  75 static int mpl3115_read_raw(struct iio_dev *indio_dev,
  76                             struct iio_chan_spec const *chan,
  77                             int *val, int *val2, long mask)
  78 {
  79         struct mpl3115_data *data = iio_priv(indio_dev);
  80         __be32 tmp = 0;
  81         int ret;
  82
  83         switch (mask) {
  84         case IIO_CHAN_INFO_RAW:
  85                 ret = iio_device_claim_direct_mode(indio_dev);
  86                 if (ret)
  87                         return ret;
  88
  89                 switch (chan->type) {
  90                 case IIO_PRESSURE: /* in 0.25 pascal / LSB */
  91                         mutex_lock(&data->lock);
  92                         ret = mpl3115_request(data);
  93                         if (ret < 0) {
  94                                 mutex_unlock(&data->lock);
  95                                 break;
  96                         }
  97                         ret = i2c_smbus_read_i2c_block_data(data->client,
  98                                 MPL3115_OUT_PRESS, 3, (u8 *) &tmp);
  99                         mutex_unlock(&data->lock);
 100                         if (ret < 0)
 101                                 break;
 102                         *val = be32_to_cpu(tmp) >> 12;
 103                         ret = IIO_VAL_INT;
 104                         break;
 105                 case IIO_TEMP: /* in 0.0625 celsius / LSB */
 106                         mutex_lock(&data->lock);
 107                         ret = mpl3115_request(data);
 108                         if (ret < 0) {
 109                                 mutex_unlock(&data->lock);
 110                                 break;
 111                         }
 112                         ret = i2c_smbus_read_i2c_block_data(data->client,
 113                                 MPL3115_OUT_TEMP, 2, (u8 *) &tmp);
 114                         mutex_unlock(&data->lock);
 115                         if (ret < 0)
 116                                 break;
 117                         *val = sign_extend32(be32_to_cpu(tmp) >> 20, 11);
 118                         ret = IIO_VAL_INT;
 119                         break;
 120                 default:
 121                         ret = -EINVAL;
 122                         break;
 123                 }
 124
 125                 iio_device_release_direct_mode(indio_dev);
 126                 return ret;
 127
 128         case IIO_CHAN_INFO_SCALE:
 129                 switch (chan->type) {
 130                 case IIO_PRESSURE:
 131                         *val = 0;
 132                         *val2 = 250; /* want kilopascal */
 133                         return IIO_VAL_INT_PLUS_MICRO;
 134                 case IIO_TEMP:
 135                         *val = 0;
 136                         *val2 = 62500;
 137                         return IIO_VAL_INT_PLUS_MICRO;
 138                 default:
 139                         return -EINVAL;
 140                 }
 141         }
 142         return -EINVAL;
 143 }
 144
 145 static irqreturn_t mpl3115_trigger_handler(int irq, void *p)
 146 {
 147         struct iio_poll_func *pf = p;
 148         struct iio_dev *indio_dev = pf->indio_dev;
 149         struct mpl3115_data *data = iio_priv(indio_dev);
 150         u8 buffer[16]; /* 32-bit channel + 16-bit channel + padding + ts */
 151         int ret, pos = 0;
 152
 153         mutex_lock(&data->lock);
 154         ret = mpl3115_request(data);
 155         if (ret < 0) {
 156                 mutex_unlock(&data->lock);
 157                 goto done;
 158         }
 159
 160         memset(buffer, 0, sizeof(buffer));
 161         if (test_bit(0, indio_dev->active_scan_mask)) {
 162                 ret = i2c_smbus_read_i2c_block_data(data->client,
 163                         MPL3115_OUT_PRESS, 3, &buffer[pos]);
 164                 if (ret < 0) {
 165                         mutex_unlock(&data->lock);
 166                         goto done;
 167                 }
 168                 pos += 4;
 169         }
 170
 171         if (test_bit(1, indio_dev->active_scan_mask)) {
 172                 ret = i2c_smbus_read_i2c_block_data(data->client,
 173                         MPL3115_OUT_TEMP, 2, &buffer[pos]);
 174                 if (ret < 0) {
 175                         mutex_unlock(&data->lock);
 176                         goto done;
 177                 }
 178         }
 179         mutex_unlock(&data->lock);
 180
 181         iio_push_to_buffers_with_timestamp(indio_dev, buffer,
 182                 iio_get_time_ns(indio_dev));
 183
 184 done:
 185         iio_trigger_notify_done(indio_dev->trig);
 186         return IRQ_HANDLED;
 187 }
 188
 189 static const struct iio_chan_spec mpl3115_channels[] = {
 190         {
 191                 .type = IIO_PRESSURE,
 192                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 193                         BIT(IIO_CHAN_INFO_SCALE),
 194                 .scan_index = 0,
 195                 .scan_type = {
 196                         .sign = 'u',
 197                         .realbits = 20,
 198                         .storagebits = 32,
 199                         .shift = 12,
 200                         .endianness = IIO_BE,
 201                 }
 202         },
 203         {
 204                 .type = IIO_TEMP,
 205                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 206                         BIT(IIO_CHAN_INFO_SCALE),
 207                 .scan_index = 1,
 208                 .scan_type = {
 209                         .sign = 's',
 210                         .realbits = 12,
 211                         .storagebits = 16,
 212                         .shift = 4,
 213                         .endianness = IIO_BE,
 214                 }
 215         },
 216         IIO_CHAN_SOFT_TIMESTAMP(2),
 217 };
 218
 219 static const struct iio_info mpl3115_info = {
 220         .read_raw = &mpl3115_read_raw,
 221         .driver_module = THIS_MODULE,
 222 };
 223
 224 static int mpl3115_probe(struct i2c_client *client,
 225                          const struct i2c_device_id *id)
 226 {
 227         struct mpl3115_data *data;
 228         struct iio_dev *indio_dev;
 229         int ret;
 230
 231         ret = i2c_smbus_read_byte_data(client, MPL3115_WHO_AM_I);
 232         if (ret < 0)
 233                 return ret;
 234         if (ret != MPL3115_DEVICE_ID)
 235                 return -ENODEV;
 236
 237         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 238         if (!indio_dev)
 239                 return -ENOMEM;
 240
 241         data = iio_priv(indio_dev);
 242         data->client = client;
 243         mutex_init(&data->lock);
 244
 245         i2c_set_clientdata(client, indio_dev);
 246         indio_dev->info = &mpl3115_info;
 247         indio_dev->name = id->name;
 248         indio_dev->dev.parent = &client->dev;
 249         indio_dev->modes = INDIO_DIRECT_MODE;
 250         indio_dev->channels = mpl3115_channels;
 251         indio_dev->num_channels = ARRAY_SIZE(mpl3115_channels);
 252
 253         /* software reset, I2C transfer is aborted (fails) */
 254         i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
 255                 MPL3115_CTRL_RESET);
 256         msleep(50);
 257
 258         data->ctrl_reg1 = MPL3115_CTRL_OS_258MS;
 259         ret = i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
 260                 data->ctrl_reg1);
 261         if (ret < 0)
 262                 return ret;
 263
 264         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 265                 mpl3115_trigger_handler, NULL);
 266         if (ret < 0)
 267                 return ret;
 268
 269         ret = iio_device_register(indio_dev);
 270         if (ret < 0)
 271                 goto buffer_cleanup;
 272         return 0;
 273
 274 buffer_cleanup:
 275         iio_triggered_buffer_cleanup(indio_dev);
 276         return ret;
 277 }
 278
 279 static int mpl3115_standby(struct mpl3115_data *data)
 280 {
 281         return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
 282                 data->ctrl_reg1 & ~MPL3115_CTRL_ACTIVE);
 283 }
 284
 285 static int mpl3115_remove(struct i2c_client *client)
 286 {
 287         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 288
 289         iio_device_unregister(indio_dev);
 290         iio_triggered_buffer_cleanup(indio_dev);
 291         mpl3115_standby(iio_priv(indio_dev));
 292
 293         return 0;
 294 }
 295
 296 #ifdef CONFIG_PM_SLEEP
 297 static int mpl3115_suspend(struct device *dev)
 298 {
 299         return mpl3115_standby(iio_priv(i2c_get_clientdata(
 300                 to_i2c_client(dev))));
 301 }
 302
 303 static int mpl3115_resume(struct device *dev)
 304 {
 305         struct mpl3115_data *data = iio_priv(i2c_get_clientdata(
 306                 to_i2c_client(dev)));
 307
 308         return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
 309                 data->ctrl_reg1);
 310 }
 311
 312 static SIMPLE_DEV_PM_OPS(mpl3115_pm_ops, mpl3115_suspend, mpl3115_resume);
 313 #define MPL3115_PM_OPS (&mpl3115_pm_ops)
 314 #else
 315 #define MPL3115_PM_OPS NULL
 316 #endif
 317
 318 static const struct i2c_device_id mpl3115_id[] = {
 319         { "mpl3115", 0 },
 320         { }
 321 };
 322 MODULE_DEVICE_TABLE(i2c, mpl3115_id);
 323
 324 static struct i2c_driver mpl3115_driver = {
 325         .driver = {
 326                 .name   = "mpl3115",
 327                 .pm     = MPL3115_PM_OPS,
 328         },
 329         .probe = mpl3115_probe,
 330         .remove = mpl3115_remove,
 331         .id_table = mpl3115_id,
 332 };
 333 module_i2c_driver(mpl3115_driver);
 334
 335 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 336 MODULE_DESCRIPTION("Freescale MPL3115 pressure/temperature driver");
 337 MODULE_LICENSE("GPL");