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_ST                                              \
 252         { .sign = 's', .realbits = 16, .storagebits = 16, .endianness = IIO_BE }
 253
 254 #define ITG3200_GYRO_CHAN(_mod) { \
 255         .type = IIO_ANGL_VEL, \
 256         .modified = 1, \
 257         .channel2 = IIO_MOD_ ## _mod, \
 258         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 259         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
 260         .address = ITG3200_REG_GYRO_ ## _mod ## OUT_H, \
 261         .scan_index = ITG3200_SCAN_GYRO_ ## _mod, \
 262         .scan_type = ITG3200_ST, \
 263 }
 264
 265 static const struct iio_chan_spec itg3200_channels[] = {
 266         {
 267                 .type = IIO_TEMP,
 268                 .channel2 = IIO_NO_MOD,
 269                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 270                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
 271                 BIT(IIO_CHAN_INFO_SCALE),
 272                 .address = ITG3200_REG_TEMP_OUT_H,
 273                 .scan_index = ITG3200_SCAN_TEMP,
 274                 .scan_type = ITG3200_ST,
 275         },
 276         ITG3200_GYRO_CHAN(X),
 277         ITG3200_GYRO_CHAN(Y),
 278         ITG3200_GYRO_CHAN(Z),
 279         IIO_CHAN_SOFT_TIMESTAMP(ITG3200_SCAN_ELEMENTS),
 280 };
 281
 282 /* IIO device attributes */
 283 static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO, itg3200_read_frequency,
 284                 itg3200_write_frequency);
 285
 286 static struct attribute *itg3200_attributes[] = {
 287         &iio_dev_attr_sampling_frequency.dev_attr.attr,
 288         NULL
 289 };
 290
 291 static const struct attribute_group itg3200_attribute_group = {
 292         .attrs = itg3200_attributes,
 293 };
 294
 295 static const struct iio_info itg3200_info = {
 296         .attrs = &itg3200_attribute_group,
 297         .read_raw = &itg3200_read_raw,
 298         .driver_module = THIS_MODULE,
 299 };
 300
 301 static const unsigned long itg3200_available_scan_masks[] = { 0xffffffff, 0x0 };
 302
 303 static int itg3200_probe(struct i2c_client *client,
 304                 const struct i2c_device_id *id)
 305 {
 306         int ret;
 307         struct itg3200 *st;
 308         struct iio_dev *indio_dev;
 309
 310         dev_dbg(&client->dev, "probe I2C dev with IRQ %i", client->irq);
 311
 312         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
 313         if (!indio_dev)
 314                 return -ENOMEM;
 315
 316         st = iio_priv(indio_dev);
 317
 318         i2c_set_clientdata(client, indio_dev);
 319         st->i2c = client;
 320
 321         indio_dev->dev.parent = &client->dev;
 322         indio_dev->name = client->dev.driver->name;
 323         indio_dev->channels = itg3200_channels;
 324         indio_dev->num_channels = ARRAY_SIZE(itg3200_channels);
 325         indio_dev->available_scan_masks = itg3200_available_scan_masks;
 326         indio_dev->info = &itg3200_info;
 327         indio_dev->modes = INDIO_DIRECT_MODE;
 328
 329         ret = itg3200_buffer_configure(indio_dev);
 330         if (ret)
 331                 return ret;
 332
 333         if (client->irq) {
 334                 ret = itg3200_probe_trigger(indio_dev);
 335                 if (ret)
 336                         goto error_unconfigure_buffer;
 337         }
 338
 339         ret = itg3200_initial_setup(indio_dev);
 340         if (ret)
 341                 goto error_remove_trigger;
 342
 343         ret = iio_device_register(indio_dev);
 344         if (ret)
 345                 goto error_remove_trigger;
 346
 347         return 0;
 348
 349 error_remove_trigger:
 350         if (client->irq)
 351                 itg3200_remove_trigger(indio_dev);
 352 error_unconfigure_buffer:
 353         itg3200_buffer_unconfigure(indio_dev);
 354         return ret;
 355 }
 356
 357 static int itg3200_remove(struct i2c_client *client)
 358 {
 359         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 360
 361         iio_device_unregister(indio_dev);
 362
 363         if (client->irq)
 364                 itg3200_remove_trigger(indio_dev);
 365
 366         itg3200_buffer_unconfigure(indio_dev);
 367
 368         return 0;
 369 }
 370
 371 static const struct i2c_device_id itg3200_id[] = {
 372         { "itg3200", 0 },
 373         { }
 374 };
 375 MODULE_DEVICE_TABLE(i2c, itg3200_id);
 376
 377 static struct i2c_driver itg3200_driver = {
 378         .driver = {
 379                 .owner  = THIS_MODULE,
 380                 .name   = "itg3200",
 381         },
 382         .id_table       = itg3200_id,
 383         .probe          = itg3200_probe,
 384         .remove         = itg3200_remove,
 385 };
 386
 387 module_i2c_driver(itg3200_driver);
 388
 389 MODULE_AUTHOR("Christian Strobel <christian.strobel@iis.fraunhofer.de>");
 390 MODULE_DESCRIPTION("ITG3200 Gyroscope I2C driver");
 391 MODULE_LICENSE("GPL v2");