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         u8 regval;
  94
  95         switch (info) {
  96         case IIO_CHAN_INFO_RAW:
  97                 reg = (u8)chan->address;
  98                 ret = itg3200_read_reg_s16(indio_dev, reg, val);
  99                 return IIO_VAL_INT;
 100         case IIO_CHAN_INFO_SCALE:
 101                 *val = 0;
 102                 if (chan->type == IIO_TEMP)
 103                         *val2 = 1000000000/280;
 104                 else
 105                         *val2 = 1214142; /* (1 / 14,375) * (PI / 180) */
 106                 return IIO_VAL_INT_PLUS_NANO;
 107         case IIO_CHAN_INFO_OFFSET:
 108                 /* Only the temperature channel has an offset */
 109                 *val = 23000;
 110                 return IIO_VAL_INT;
 111         case IIO_CHAN_INFO_SAMP_FREQ:
 112                 ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &regval);
 113                 if (ret)
 114                         return ret;
 115
 116                 *val = (regval & ITG3200_DLPF_CFG_MASK) ? 1000 : 8000;
 117
 118                 ret = itg3200_read_reg_8(indio_dev,
 119                                          ITG3200_REG_SAMPLE_RATE_DIV,
 120                                          &regval);
 121                 if (ret)
 122                         return ret;
 123
 124                 *val /= regval + 1;
 125                 return IIO_VAL_INT;
 126
 127         default:
 128                 return -EINVAL;
 129         }
 130 }
 131
 132 static int itg3200_write_raw(struct iio_dev *indio_dev,
 133                              struct iio_chan_spec const *chan,
 134                              int val,
 135                              int val2,
 136                              long mask)
 137 {
 138         int ret;
 139         u8 t;
 140
 141         switch (mask) {
 142         case IIO_CHAN_INFO_SAMP_FREQ:
 143                 if (val == 0 || val2 != 0)
 144                         return -EINVAL;
 145
 146                 mutex_lock(&indio_dev->mlock);
 147
 148                 ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &t);
 149                 if (ret) {
 150                         mutex_unlock(&indio_dev->mlock);
 151                         return ret;
 152                 }
 153                 t = ((t & ITG3200_DLPF_CFG_MASK) ? 1000u : 8000u) / val - 1;
 154
 155                 ret = itg3200_write_reg_8(indio_dev,
 156                                           ITG3200_REG_SAMPLE_RATE_DIV,
 157                                           t);
 158
 159                 mutex_unlock(&indio_dev->mlock);
 160         return ret;
 161
 162         default:
 163                 return -EINVAL;
 164         }
 165 }
 166
 167 /*
 168  * Reset device and internal registers to the power-up-default settings
 169  * Use the gyro clock as reference, as suggested by the datasheet
 170  */
 171 static int itg3200_reset(struct iio_dev *indio_dev)
 172 {
 173         struct itg3200 *st = iio_priv(indio_dev);
 174         int ret;
 175
 176         dev_dbg(&st->i2c->dev, "reset device");
 177
 178         ret = itg3200_write_reg_8(indio_dev,
 179                         ITG3200_REG_POWER_MANAGEMENT,
 180                         ITG3200_RESET);
 181         if (ret) {
 182                 dev_err(&st->i2c->dev, "error resetting device");
 183                 goto error_ret;
 184         }
 185
 186         /* Wait for PLL (1ms according to datasheet) */
 187         udelay(1500);
 188
 189         ret = itg3200_write_reg_8(indio_dev,
 190                         ITG3200_REG_IRQ_CONFIG,
 191                         ITG3200_IRQ_ACTIVE_HIGH |
 192                         ITG3200_IRQ_PUSH_PULL |
 193                         ITG3200_IRQ_LATCH_50US_PULSE |
 194                         ITG3200_IRQ_LATCH_CLEAR_ANY);
 195
 196         if (ret)
 197                 dev_err(&st->i2c->dev, "error init device");
 198
 199 error_ret:
 200         return ret;
 201 }
 202
 203 /* itg3200_enable_full_scale() - Disables the digital low pass filter */
 204 static int itg3200_enable_full_scale(struct iio_dev *indio_dev)
 205 {
 206         u8 val;
 207         int ret;
 208
 209         ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &val);
 210         if (ret)
 211                 goto err_ret;
 212
 213         val |= ITG3200_DLPF_FS_SEL_2000;
 214         return itg3200_write_reg_8(indio_dev, ITG3200_REG_DLPF, val);
 215
 216 err_ret:
 217         return ret;
 218 }
 219
 220 static int itg3200_initial_setup(struct iio_dev *indio_dev)
 221 {
 222         struct itg3200 *st = iio_priv(indio_dev);
 223         int ret;
 224         u8 val;
 225
 226         ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_ADDRESS, &val);
 227         if (ret)
 228                 goto err_ret;
 229
 230         if (((val >> 1) & 0x3f) != 0x34) {
 231                 dev_err(&st->i2c->dev, "invalid reg value 0x%02x", val);
 232                 ret = -ENXIO;
 233                 goto err_ret;
 234         }
 235
 236         ret = itg3200_reset(indio_dev);
 237         if (ret)
 238                 goto err_ret;
 239
 240         ret = itg3200_enable_full_scale(indio_dev);
 241 err_ret:
 242         return ret;
 243 }
 244
 245 #define ITG3200_ST                                              \
 246         { .sign = 's', .realbits = 16, .storagebits = 16, .endianness = IIO_BE }
 247
 248 #define ITG3200_GYRO_CHAN(_mod) { \
 249         .type = IIO_ANGL_VEL, \
 250         .modified = 1, \
 251         .channel2 = IIO_MOD_ ## _mod, \
 252         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 253         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
 254         .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
 255         .address = ITG3200_REG_GYRO_ ## _mod ## OUT_H, \
 256         .scan_index = ITG3200_SCAN_GYRO_ ## _mod, \
 257         .scan_type = ITG3200_ST, \
 258 }
 259
 260 static const struct iio_chan_spec itg3200_channels[] = {
 261         {
 262                 .type = IIO_TEMP,
 263                 .channel2 = IIO_NO_MOD,
 264                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 265                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
 266                 BIT(IIO_CHAN_INFO_SCALE),
 267                 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 268                 .address = ITG3200_REG_TEMP_OUT_H,
 269                 .scan_index = ITG3200_SCAN_TEMP,
 270                 .scan_type = ITG3200_ST,
 271         },
 272         ITG3200_GYRO_CHAN(X),
 273         ITG3200_GYRO_CHAN(Y),
 274         ITG3200_GYRO_CHAN(Z),
 275         IIO_CHAN_SOFT_TIMESTAMP(ITG3200_SCAN_ELEMENTS),
 276 };
 277
 278 static const struct iio_info itg3200_info = {
 279         .read_raw = &itg3200_read_raw,
 280         .write_raw = &itg3200_write_raw,
 281         .driver_module = THIS_MODULE,
 282 };
 283
 284 static const unsigned long itg3200_available_scan_masks[] = { 0xffffffff, 0x0 };
 285
 286 static int itg3200_probe(struct i2c_client *client,
 287                 const struct i2c_device_id *id)
 288 {
 289         int ret;
 290         struct itg3200 *st;
 291         struct iio_dev *indio_dev;
 292
 293         dev_dbg(&client->dev, "probe I2C dev with IRQ %i", client->irq);
 294
 295         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
 296         if (!indio_dev)
 297                 return -ENOMEM;
 298
 299         st = iio_priv(indio_dev);
 300
 301         i2c_set_clientdata(client, indio_dev);
 302         st->i2c = client;
 303
 304         indio_dev->dev.parent = &client->dev;
 305         indio_dev->name = client->dev.driver->name;
 306         indio_dev->channels = itg3200_channels;
 307         indio_dev->num_channels = ARRAY_SIZE(itg3200_channels);
 308         indio_dev->available_scan_masks = itg3200_available_scan_masks;
 309         indio_dev->info = &itg3200_info;
 310         indio_dev->modes = INDIO_DIRECT_MODE;
 311
 312         ret = itg3200_buffer_configure(indio_dev);
 313         if (ret)
 314                 return ret;
 315
 316         if (client->irq) {
 317                 ret = itg3200_probe_trigger(indio_dev);
 318                 if (ret)
 319                         goto error_unconfigure_buffer;
 320         }
 321
 322         ret = itg3200_initial_setup(indio_dev);
 323         if (ret)
 324                 goto error_remove_trigger;
 325
 326         ret = iio_device_register(indio_dev);
 327         if (ret)
 328                 goto error_remove_trigger;
 329
 330         return 0;
 331
 332 error_remove_trigger:
 333         if (client->irq)
 334                 itg3200_remove_trigger(indio_dev);
 335 error_unconfigure_buffer:
 336         itg3200_buffer_unconfigure(indio_dev);
 337         return ret;
 338 }
 339
 340 static int itg3200_remove(struct i2c_client *client)
 341 {
 342         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 343
 344         iio_device_unregister(indio_dev);
 345
 346         if (client->irq)
 347                 itg3200_remove_trigger(indio_dev);
 348
 349         itg3200_buffer_unconfigure(indio_dev);
 350
 351         return 0;
 352 }
 353
 354 static const struct i2c_device_id itg3200_id[] = {
 355         { "itg3200", 0 },
 356         { }
 357 };
 358 MODULE_DEVICE_TABLE(i2c, itg3200_id);
 359
 360 static struct i2c_driver itg3200_driver = {
 361         .driver = {
 362                 .owner  = THIS_MODULE,
 363                 .name   = "itg3200",
 364         },
 365         .id_table       = itg3200_id,
 366         .probe          = itg3200_probe,
 367         .remove         = itg3200_remove,
 368 };
 369
 370 module_i2c_driver(itg3200_driver);
 371
 372 MODULE_AUTHOR("Christian Strobel <christian.strobel@iis.fraunhofer.de>");
 373 MODULE_DESCRIPTION("ITG3200 Gyroscope I2C driver");
 374 MODULE_LICENSE("GPL v2");