drivers/iio/pressure/mpl3115.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * mpl3115.c - Support for Freescale MPL3115A2 pressure/temperature sensor
   4  *
   5  * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
   6  *
   7  * (7-bit I2C slave address 0x60)
   8  *
   9  * TODO: FIFO buffer, altimeter mode, oversampling, continuous mode,
  10  * interrupts, user offset correction, raw mode
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/i2c.h>
  15 #include <linux/iio/iio.h>
  16 #include <linux/iio/sysfs.h>
  17 #include <linux/iio/trigger_consumer.h>
  18 #include <linux/iio/buffer.h>
  19 #include <linux/iio/triggered_buffer.h>
  20 #include <linux/delay.h>
  21
  22 #define MPL3115_STATUS 0x00
  23 #define MPL3115_OUT_PRESS 0x01 /* MSB first, 20 bit */
  24 #define MPL3115_OUT_TEMP 0x04 /* MSB first, 12 bit */
  25 #define MPL3115_WHO_AM_I 0x0c
  26 #define MPL3115_CTRL_REG1 0x26
  27
  28 #define MPL3115_DEVICE_ID 0xc4
  29
  30 #define MPL3115_STATUS_PRESS_RDY BIT(2)
  31 #define MPL3115_STATUS_TEMP_RDY BIT(1)
  32
  33 #define MPL3115_CTRL_RESET BIT(2) /* software reset */
  34 #define MPL3115_CTRL_OST BIT(1) /* initiate measurement */
  35 #define MPL3115_CTRL_ACTIVE BIT(0) /* continuous measurement */
  36 #define MPL3115_CTRL_OS_258MS (BIT(5) | BIT(4)) /* 64x oversampling */
  37
  38 struct mpl3115_data {
  39         struct i2c_client *client;
  40         struct mutex lock;
  41         u8 ctrl_reg1;
  42 };
  43
  44 static int mpl3115_request(struct mpl3115_data *data)
  45 {
  46         int ret, tries = 15;
  47
  48         /* trigger measurement */
  49         ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
  50                 data->ctrl_reg1 | MPL3115_CTRL_OST);
  51         if (ret < 0)
  52                 return ret;
  53
  54         while (tries-- > 0) {
  55                 ret = i2c_smbus_read_byte_data(data->client, MPL3115_CTRL_REG1);
  56                 if (ret < 0)
  57                         return ret;
  58                 /* wait for data ready, i.e. OST cleared */
  59                 if (!(ret & MPL3115_CTRL_OST))
  60                         break;
  61                 msleep(20);
  62         }
  63
  64         if (tries < 0) {
  65                 dev_err(&data->client->dev, "data not ready\n");
  66                 return -EIO;
  67         }
  68
  69         return 0;
  70 }
  71
  72 static int mpl3115_read_raw(struct iio_dev *indio_dev,
  73                             struct iio_chan_spec const *chan,
  74                             int *val, int *val2, long mask)
  75 {
  76         struct mpl3115_data *data = iio_priv(indio_dev);
  77         __be32 tmp = 0;
  78         int ret;
  79
  80         switch (mask) {
  81         case IIO_CHAN_INFO_RAW:
  82                 ret = iio_device_claim_direct_mode(indio_dev);
  83                 if (ret)
  84                         return ret;
  85
  86                 switch (chan->type) {
  87                 case IIO_PRESSURE: /* in 0.25 pascal / LSB */
  88                         mutex_lock(&data->lock);
  89                         ret = mpl3115_request(data);
  90                         if (ret < 0) {
  91                                 mutex_unlock(&data->lock);
  92                                 break;
  93                         }
  94                         ret = i2c_smbus_read_i2c_block_data(data->client,
  95                                 MPL3115_OUT_PRESS, 3, (u8 *) &tmp);
  96                         mutex_unlock(&data->lock);
  97                         if (ret < 0)
  98                                 break;
  99                         *val = be32_to_cpu(tmp) >> 12;
 100                         ret = IIO_VAL_INT;
 101                         break;
 102                 case IIO_TEMP: /* in 0.0625 celsius / LSB */
 103                         mutex_lock(&data->lock);
 104                         ret = mpl3115_request(data);
 105                         if (ret < 0) {
 106                                 mutex_unlock(&data->lock);
 107                                 break;
 108                         }
 109                         ret = i2c_smbus_read_i2c_block_data(data->client,
 110                                 MPL3115_OUT_TEMP, 2, (u8 *) &tmp);
 111                         mutex_unlock(&data->lock);
 112                         if (ret < 0)
 113                                 break;
 114                         *val = sign_extend32(be32_to_cpu(tmp) >> 20, 11);
 115                         ret = IIO_VAL_INT;
 116                         break;
 117                 default:
 118                         ret = -EINVAL;
 119                         break;
 120                 }
 121
 122                 iio_device_release_direct_mode(indio_dev);
 123                 return ret;
 124
 125         case IIO_CHAN_INFO_SCALE:
 126                 switch (chan->type) {
 127                 case IIO_PRESSURE:
 128                         *val = 0;
 129                         *val2 = 250; /* want kilopascal */
 130                         return IIO_VAL_INT_PLUS_MICRO;
 131                 case IIO_TEMP:
 132                         *val = 0;
 133                         *val2 = 62500;
 134                         return IIO_VAL_INT_PLUS_MICRO;
 135                 default:
 136                         return -EINVAL;
 137                 }
 138         }
 139         return -EINVAL;
 140 }
 141
 142 static irqreturn_t mpl3115_trigger_handler(int irq, void *p)
 143 {
 144         struct iio_poll_func *pf = p;
 145         struct iio_dev *indio_dev = pf->indio_dev;
 146         struct mpl3115_data *data = iio_priv(indio_dev);
 147         /*
 148          * 32-bit channel + 16-bit channel + padding + ts
 149          * Note that it is possible for only one of the first 2
 150          * channels to be enabled. If that happens, the first element
 151          * of the buffer may be either 16 or 32-bits.  As such we cannot
 152          * use a simple structure definition to express this data layout.
 153          */
 154         u8 buffer[16] __aligned(8);
 155         int ret, pos = 0;
 156
 157         mutex_lock(&data->lock);
 158         ret = mpl3115_request(data);
 159         if (ret < 0) {
 160                 mutex_unlock(&data->lock);
 161                 goto done;
 162         }
 163
 164         memset(buffer, 0, sizeof(buffer));
 165         if (test_bit(0, indio_dev->active_scan_mask)) {
 166                 ret = i2c_smbus_read_i2c_block_data(data->client,
 167                         MPL3115_OUT_PRESS, 3, &buffer[pos]);
 168                 if (ret < 0) {
 169                         mutex_unlock(&data->lock);
 170                         goto done;
 171                 }
 172                 pos += 4;
 173         }
 174
 175         if (test_bit(1, indio_dev->active_scan_mask)) {
 176                 ret = i2c_smbus_read_i2c_block_data(data->client,
 177                         MPL3115_OUT_TEMP, 2, &buffer[pos]);
 178                 if (ret < 0) {
 179                         mutex_unlock(&data->lock);
 180                         goto done;
 181                 }
 182         }
 183         mutex_unlock(&data->lock);
 184
 185         iio_push_to_buffers_with_timestamp(indio_dev, buffer,
 186                 iio_get_time_ns(indio_dev));
 187
 188 done:
 189         iio_trigger_notify_done(indio_dev->trig);
 190         return IRQ_HANDLED;
 191 }
 192
 193 static const struct iio_chan_spec mpl3115_channels[] = {
 194         {
 195                 .type = IIO_PRESSURE,
 196                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 197                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 198                 .scan_index = 0,
 199                 .scan_type = {
 200                         .sign = 'u',
 201                         .realbits = 20,
 202                         .storagebits = 32,
 203                         .shift = 12,
 204                         .endianness = IIO_BE,
 205                 }
 206         },
 207         {
 208                 .type = IIO_TEMP,
 209                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 210                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 211                 .scan_index = 1,
 212                 .scan_type = {
 213                         .sign = 's',
 214                         .realbits = 12,
 215                         .storagebits = 16,
 216                         .shift = 4,
 217                         .endianness = IIO_BE,
 218                 }
 219         },
 220         IIO_CHAN_SOFT_TIMESTAMP(2),
 221 };
 222
 223 static const struct iio_info mpl3115_info = {
 224         .read_raw = &mpl3115_read_raw,
 225 };
 226
 227 static int mpl3115_probe(struct i2c_client *client,
 228                          const struct i2c_device_id *id)
 229 {
 230         struct mpl3115_data *data;
 231         struct iio_dev *indio_dev;
 232         int ret;
 233
 234         ret = i2c_smbus_read_byte_data(client, MPL3115_WHO_AM_I);
 235         if (ret < 0)
 236                 return ret;
 237         if (ret != MPL3115_DEVICE_ID)
 238                 return -ENODEV;
 239
 240         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 241         if (!indio_dev)
 242                 return -ENOMEM;
 243
 244         data = iio_priv(indio_dev);
 245         data->client = client;
 246         mutex_init(&data->lock);
 247
 248         i2c_set_clientdata(client, indio_dev);
 249         indio_dev->info = &mpl3115_info;
 250         indio_dev->name = id->name;
 251         indio_dev->modes = INDIO_DIRECT_MODE;
 252         indio_dev->channels = mpl3115_channels;
 253         indio_dev->num_channels = ARRAY_SIZE(mpl3115_channels);
 254
 255         /* software reset, I2C transfer is aborted (fails) */
 256         i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
 257                 MPL3115_CTRL_RESET);
 258         msleep(50);
 259
 260         data->ctrl_reg1 = MPL3115_CTRL_OS_258MS;
 261         ret = i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
 262                 data->ctrl_reg1);
 263         if (ret < 0)
 264                 return ret;
 265
 266         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 267                 mpl3115_trigger_handler, NULL);
 268         if (ret < 0)
 269                 return ret;
 270
 271         ret = iio_device_register(indio_dev);
 272         if (ret < 0)
 273                 goto buffer_cleanup;
 274         return 0;
 275
 276 buffer_cleanup:
 277         iio_triggered_buffer_cleanup(indio_dev);
 278         return ret;
 279 }
 280
 281 static int mpl3115_standby(struct mpl3115_data *data)
 282 {
 283         return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
 284                 data->ctrl_reg1 & ~MPL3115_CTRL_ACTIVE);
 285 }
 286
 287 static int mpl3115_remove(struct i2c_client *client)
 288 {
 289         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 290
 291         iio_device_unregister(indio_dev);
 292         iio_triggered_buffer_cleanup(indio_dev);
 293         mpl3115_standby(iio_priv(indio_dev));
 294
 295         return 0;
 296 }
 297
 298 #ifdef CONFIG_PM_SLEEP
 299 static int mpl3115_suspend(struct device *dev)
 300 {
 301         return mpl3115_standby(iio_priv(i2c_get_clientdata(
 302                 to_i2c_client(dev))));
 303 }
 304
 305 static int mpl3115_resume(struct device *dev)
 306 {
 307         struct mpl3115_data *data = iio_priv(i2c_get_clientdata(
 308                 to_i2c_client(dev)));
 309
 310         return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
 311                 data->ctrl_reg1);
 312 }
 313
 314 static SIMPLE_DEV_PM_OPS(mpl3115_pm_ops, mpl3115_suspend, mpl3115_resume);
 315 #define MPL3115_PM_OPS (&mpl3115_pm_ops)
 316 #else
 317 #define MPL3115_PM_OPS NULL
 318 #endif
 319
 320 static const struct i2c_device_id mpl3115_id[] = {
 321         { "mpl3115", 0 },
 322         { }
 323 };
 324 MODULE_DEVICE_TABLE(i2c, mpl3115_id);
 325
 326 static const struct of_device_id mpl3115_of_match[] = {
 327         { .compatible = "fsl,mpl3115" },
 328         { }
 329 };
 330 MODULE_DEVICE_TABLE(of, mpl3115_of_match);
 331
 332 static struct i2c_driver mpl3115_driver = {
 333         .driver = {
 334                 .name   = "mpl3115",
 335                 .of_match_table = mpl3115_of_match,
 336                 .pm     = MPL3115_PM_OPS,
 337         },
 338         .probe = mpl3115_probe,
 339         .remove = mpl3115_remove,
 340         .id_table = mpl3115_id,
 341 };
 342 module_i2c_driver(mpl3115_driver);
 343
 344 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 345 MODULE_DESCRIPTION("Freescale MPL3115 pressure/temperature driver");
 346 MODULE_LICENSE("GPL");