drivers/iio/gyro/itg3200_core.c

   1 /*
   2  * itg3200_core.c -- support InvenSense ITG3200
   3  *                   Digital 3-Axis Gyroscope driver
   4  *
   5  * Copyright (c) 2011 Christian Strobel <christian.strobel@iis.fraunhofer.de>
   6  * Copyright (c) 2011 Manuel Stahl <manuel.stahl@iis.fraunhofer.de>
   7  * Copyright (c) 2012 Thorsten Nowak <thorsten.nowak@iis.fraunhofer.de>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * TODO:
  14  * - Support digital low pass filter
  15  * - Support power management
  16  */
  17
  18 #include <linux/interrupt.h>
  19 #include <linux/irq.h>
  20 #include <linux/i2c.h>
  21 #include <linux/gpio.h>
  22 #include <linux/slab.h>
  23 #include <linux/stat.h>
  24 #include <linux/module.h>
  25 #include <linux/delay.h>
  26
  27 #include <linux/iio/iio.h>
  28 #include <linux/iio/sysfs.h>
  29 #include <linux/iio/events.h>
  30 #include <linux/iio/buffer.h>
  31
  32 #include <linux/iio/gyro/itg3200.h>
  33
  34
  35 int itg3200_write_reg_8(struct iio_dev *indio_dev,
  36                 u8 reg_address, u8 val)
  37 {
  38         struct itg3200 *st = iio_priv(indio_dev);
  39
  40         return i2c_smbus_write_byte_data(st->i2c, 0x80 | reg_address, val);
  41 }
  42
  43 int itg3200_read_reg_8(struct iio_dev *indio_dev,
  44                 u8 reg_address, u8 *val)
  45 {
  46         struct itg3200 *st = iio_priv(indio_dev);
  47         int ret;
  48
  49         ret = i2c_smbus_read_byte_data(st->i2c, reg_address);
  50         if (ret < 0)
  51                 return ret;
  52         *val = ret;
  53         return 0;
  54 }
  55
  56 static int itg3200_read_reg_s16(struct iio_dev *indio_dev, u8 lower_reg_address,
  57                 int *val)
  58 {
  59         struct itg3200 *st = iio_priv(indio_dev);
  60         struct i2c_client *client = st->i2c;
  61         int ret;
  62         s16 out;
  63
  64         struct i2c_msg msg[2] = {
  65                 {
  66                         .addr = client->addr,
  67                         .flags = client->flags,
  68                         .len = 1,
  69                         .buf = (char *)&lower_reg_address,
  70                 },
  71                 {
  72                         .addr = client->addr,
  73                         .flags = client->flags | I2C_M_RD,
  74                         .len = 2,
  75                         .buf = (char *)&out,
  76                 },
  77         };
  78
  79         lower_reg_address |= 0x80;
  80         ret = i2c_transfer(client->adapter, msg, 2);
  81         be16_to_cpus(&out);
  82         *val = out;
  83
  84         return (ret == 2) ? 0 : ret;
  85 }
  86
  87 static int itg3200_read_raw(struct iio_dev *indio_dev,
  88                 const struct iio_chan_spec *chan,
  89                 int *val, int *val2, long info)
  90 {
  91         int ret = 0;
  92         u8 reg;
  93
  94         switch (info) {
  95         case IIO_CHAN_INFO_RAW:
  96                 reg = (u8)chan->address;
  97                 ret = itg3200_read_reg_s16(indio_dev, reg, val);
  98                 return IIO_VAL_INT;
  99         case IIO_CHAN_INFO_SCALE:
 100                 *val = 0;
 101                 if (chan->type == IIO_TEMP)
 102                         *val2 = 1000000000/280;
 103                 else
 104                         *val2 = 1214142; /* (1 / 14,375) * (PI / 180) */
 105                 return IIO_VAL_INT_PLUS_NANO;
 106         case IIO_CHAN_INFO_OFFSET:
 107                 /* Only the temperature channel has an offset */
 108                 *val = 23000;
 109                 return IIO_VAL_INT;
 110         default:
 111                 return -EINVAL;
 112         }
 113
 114         return ret;
 115 }
 116
 117 static ssize_t itg3200_read_frequency(struct device *dev,
 118                 struct device_attribute *attr, char *buf)
 119 {
 120         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 121         int ret, sps;
 122         u8 val;
 123
 124         ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &val);
 125         if (ret)
 126                 return ret;
 127
 128         sps = (val & ITG3200_DLPF_CFG_MASK) ? 1000 : 8000;
 129
 130         ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_SAMPLE_RATE_DIV, &val);
 131         if (ret)
 132                 return ret;
 133
 134         sps /= val + 1;
 135
 136         return sprintf(buf, "%d\n", sps);
 137 }
 138
 139 static ssize_t itg3200_write_frequency(struct device *dev,
 140                 struct device_attribute *attr,
 141                 const char *buf,
 142                 size_t len)
 143 {
 144         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 145         unsigned val;
 146         int ret;
 147         u8 t;
 148
 149         ret = kstrtouint(buf, 10, &val);
 150         if (ret)
 151                 return ret;
 152
 153         mutex_lock(&indio_dev->mlock);
 154
 155         ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &t);
 156         if (ret)
 157                 goto err_ret;
 158
 159         if (val == 0) {
 160                 ret = -EINVAL;
 161                 goto err_ret;
 162         }
 163         t = ((t & ITG3200_DLPF_CFG_MASK) ? 1000u : 8000u) / val - 1;
 164
 165         ret = itg3200_write_reg_8(indio_dev, ITG3200_REG_SAMPLE_RATE_DIV, t);
 166
 167 err_ret:
 168         mutex_unlock(&indio_dev->mlock);
 169
 170         return ret ? ret : len;
 171 }
 172
 173 /*
 174  * Reset device and internal registers to the power-up-default settings
 175  * Use the gyro clock as reference, as suggested by the datasheet
 176  */
 177 static int itg3200_reset(struct iio_dev *indio_dev)
 178 {
 179         struct itg3200 *st = iio_priv(indio_dev);
 180         int ret;
 181
 182         dev_dbg(&st->i2c->dev, "reset device");
 183
 184         ret = itg3200_write_reg_8(indio_dev,
 185                         ITG3200_REG_POWER_MANAGEMENT,
 186                         ITG3200_RESET);
 187         if (ret) {
 188                 dev_err(&st->i2c->dev, "error resetting device");
 189                 goto error_ret;
 190         }
 191
 192         /* Wait for PLL (1ms according to datasheet) */
 193         udelay(1500);
 194
 195         ret = itg3200_write_reg_8(indio_dev,
 196                         ITG3200_REG_IRQ_CONFIG,
 197                         ITG3200_IRQ_ACTIVE_HIGH |
 198                         ITG3200_IRQ_PUSH_PULL |
 199                         ITG3200_IRQ_LATCH_50US_PULSE |
 200                         ITG3200_IRQ_LATCH_CLEAR_ANY);
 201
 202         if (ret)
 203                 dev_err(&st->i2c->dev, "error init device");
 204
 205 error_ret:
 206         return ret;
 207 }
 208
 209 /* itg3200_enable_full_scale() - Disables the digital low pass filter */
 210 static int itg3200_enable_full_scale(struct iio_dev *indio_dev)
 211 {
 212         u8 val;
 213         int ret;
 214
 215         ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &val);
 216         if (ret)
 217                 goto err_ret;
 218
 219         val |= ITG3200_DLPF_FS_SEL_2000;
 220         return itg3200_write_reg_8(indio_dev, ITG3200_REG_DLPF, val);
 221
 222 err_ret:
 223         return ret;
 224 }
 225
 226 static int itg3200_initial_setup(struct iio_dev *indio_dev)
 227 {
 228         struct itg3200 *st = iio_priv(indio_dev);
 229         int ret;
 230         u8 val;
 231
 232         ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_ADDRESS, &val);
 233         if (ret)
 234                 goto err_ret;
 235
 236         if (((val >> 1) & 0x3f) != 0x34) {
 237                 dev_err(&st->i2c->dev, "invalid reg value 0x%02x", val);
 238                 ret = -ENXIO;
 239                 goto err_ret;
 240         }
 241
 242         ret = itg3200_reset(indio_dev);
 243         if (ret)
 244                 goto err_ret;
 245
 246         ret = itg3200_enable_full_scale(indio_dev);
 247 err_ret:
 248         return ret;
 249 }
 250
 251 #define ITG3200_TEMP_INFO_MASK  (IIO_CHAN_INFO_OFFSET_SHARED_BIT | \
 252                                  IIO_CHAN_INFO_SCALE_SHARED_BIT | \
 253                                  IIO_CHAN_INFO_RAW_SEPARATE_BIT)
 254 #define ITG3200_GYRO_INFO_MASK  (IIO_CHAN_INFO_SCALE_SHARED_BIT | \
 255                                  IIO_CHAN_INFO_RAW_SEPARATE_BIT)
 256
 257 #define ITG3200_ST                                              \
 258         { .sign = 's', .realbits = 16, .storagebits = 16, .endianness = IIO_BE }
 259
 260 #define ITG3200_GYRO_CHAN(_mod) { \
 261         .type = IIO_ANGL_VEL, \
 262         .modified = 1, \
 263         .channel2 = IIO_MOD_ ## _mod, \
 264         .info_mask = ITG3200_GYRO_INFO_MASK, \
 265         .address = ITG3200_REG_GYRO_ ## _mod ## OUT_H, \
 266         .scan_index = ITG3200_SCAN_GYRO_ ## _mod, \
 267         .scan_type = ITG3200_ST, \
 268 }
 269
 270 static const struct iio_chan_spec itg3200_channels[] = {
 271         {
 272                 .type = IIO_TEMP,
 273                 .channel2 = IIO_NO_MOD,
 274                 .info_mask = ITG3200_TEMP_INFO_MASK,
 275                 .address = ITG3200_REG_TEMP_OUT_H,
 276                 .scan_index = ITG3200_SCAN_TEMP,
 277                 .scan_type = ITG3200_ST,
 278         },
 279         ITG3200_GYRO_CHAN(X),
 280         ITG3200_GYRO_CHAN(Y),
 281         ITG3200_GYRO_CHAN(Z),
 282         IIO_CHAN_SOFT_TIMESTAMP(ITG3200_SCAN_ELEMENTS),
 283 };
 284
 285 /* IIO device attributes */
 286 static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO, itg3200_read_frequency,
 287                 itg3200_write_frequency);
 288
 289 static struct attribute *itg3200_attributes[] = {
 290         &iio_dev_attr_sampling_frequency.dev_attr.attr,
 291         NULL
 292 };
 293
 294 static const struct attribute_group itg3200_attribute_group = {
 295         .attrs = itg3200_attributes,
 296 };
 297
 298 static const struct iio_info itg3200_info = {
 299         .attrs = &itg3200_attribute_group,
 300         .read_raw = &itg3200_read_raw,
 301         .driver_module = THIS_MODULE,
 302 };
 303
 304 static const unsigned long itg3200_available_scan_masks[] = { 0xffffffff, 0x0 };
 305
 306 static int itg3200_probe(struct i2c_client *client,
 307                 const struct i2c_device_id *id)
 308 {
 309         int ret;
 310         struct itg3200 *st;
 311         struct iio_dev *indio_dev;
 312
 313         dev_dbg(&client->dev, "probe I2C dev with IRQ %i", client->irq);
 314
 315         indio_dev = iio_device_alloc(sizeof(*st));
 316         if (indio_dev == NULL) {
 317                 ret =  -ENOMEM;
 318                 goto error_ret;
 319         }
 320
 321         st = iio_priv(indio_dev);
 322
 323         i2c_set_clientdata(client, indio_dev);
 324         st->i2c = client;
 325
 326         indio_dev->dev.parent = &client->dev;
 327         indio_dev->name = client->dev.driver->name;
 328         indio_dev->channels = itg3200_channels;
 329         indio_dev->num_channels = ARRAY_SIZE(itg3200_channels);
 330         indio_dev->available_scan_masks = itg3200_available_scan_masks;
 331         indio_dev->info = &itg3200_info;
 332         indio_dev->modes = INDIO_DIRECT_MODE;
 333
 334         ret = itg3200_buffer_configure(indio_dev);
 335         if (ret)
 336                 goto error_free_dev;
 337
 338         if (client->irq) {
 339                 ret = itg3200_probe_trigger(indio_dev);
 340                 if (ret)
 341                         goto error_unconfigure_buffer;
 342         }
 343
 344         ret = itg3200_initial_setup(indio_dev);
 345         if (ret)
 346                 goto error_remove_trigger;
 347
 348         ret = iio_device_register(indio_dev);
 349         if (ret)
 350                 goto error_remove_trigger;
 351
 352         return 0;
 353
 354 error_remove_trigger:
 355         if (client->irq)
 356                 itg3200_remove_trigger(indio_dev);
 357 error_unconfigure_buffer:
 358         itg3200_buffer_unconfigure(indio_dev);
 359 error_free_dev:
 360         iio_device_free(indio_dev);
 361 error_ret:
 362         return ret;
 363 }
 364
 365 static int itg3200_remove(struct i2c_client *client)
 366 {
 367         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 368
 369         iio_device_unregister(indio_dev);
 370
 371         if (client->irq)
 372                 itg3200_remove_trigger(indio_dev);
 373
 374         itg3200_buffer_unconfigure(indio_dev);
 375
 376         iio_device_free(indio_dev);
 377
 378         return 0;
 379 }
 380
 381 static const struct i2c_device_id itg3200_id[] = {
 382         { "itg3200", 0 },
 383         { }
 384 };
 385 MODULE_DEVICE_TABLE(i2c, itg3200_id);
 386
 387 static struct i2c_driver itg3200_driver = {
 388         .driver = {
 389                 .owner  = THIS_MODULE,
 390                 .name   = "itg3200",
 391         },
 392         .id_table       = itg3200_id,
 393         .probe          = itg3200_probe,
 394         .remove         = itg3200_remove,
 395 };
 396
 397 module_i2c_driver(itg3200_driver);
 398
 399 MODULE_AUTHOR("Christian Strobel <christian.strobel@iis.fraunhofer.de>");
 400 MODULE_DESCRIPTION("ITG3200 Gyroscope I2C driver");
 401 MODULE_LICENSE("GPL v2");