drivers/iio/proximity/pulsedlight-lidar-lite-v2.c

   1 /*
   2  * pulsedlight-lidar-lite-v2.c - Support for PulsedLight LIDAR sensor
   3  *
   4  * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * TODO: runtime pm, interrupt mode, and signal strength reporting
  17  */
  18
  19 #include <linux/err.h>
  20 #include <linux/init.h>
  21 #include <linux/i2c.h>
  22 #include <linux/delay.h>
  23 #include <linux/module.h>
  24 #include <linux/iio/iio.h>
  25 #include <linux/iio/sysfs.h>
  26 #include <linux/iio/buffer.h>
  27 #include <linux/iio/trigger.h>
  28 #include <linux/iio/triggered_buffer.h>
  29 #include <linux/iio/trigger_consumer.h>
  30
  31 #define LIDAR_REG_CONTROL               0x00
  32 #define LIDAR_REG_CONTROL_ACQUIRE       BIT(2)
  33
  34 #define LIDAR_REG_STATUS                0x01
  35 #define LIDAR_REG_STATUS_INVALID        BIT(3)
  36 #define LIDAR_REG_STATUS_READY          BIT(0)
  37
  38 #define LIDAR_REG_DATA_HBYTE    0x0f
  39 #define LIDAR_REG_DATA_LBYTE    0x10
  40
  41 #define LIDAR_DRV_NAME "lidar"
  42
  43 struct lidar_data {
  44         struct iio_dev *indio_dev;
  45         struct i2c_client *client;
  46
  47         u16 buffer[8]; /* 2 byte distance + 8 byte timestamp */
  48 };
  49
  50 static const struct iio_chan_spec lidar_channels[] = {
  51         {
  52                 .type = IIO_DISTANCE,
  53                 .info_mask_separate =
  54                         BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
  55                 .scan_index = 0,
  56                 .scan_type = {
  57                         .sign = 'u',
  58                         .realbits = 16,
  59                         .storagebits = 16,
  60                 },
  61         },
  62         IIO_CHAN_SOFT_TIMESTAMP(1),
  63 };
  64
  65 static int lidar_read_byte(struct lidar_data *data, int reg)
  66 {
  67         struct i2c_client *client = data->client;
  68         int ret;
  69
  70         /*
  71          * Device needs a STOP condition between address write, and data read
  72          * so in turn i2c_smbus_read_byte_data cannot be used
  73          */
  74
  75         ret = i2c_smbus_write_byte(client, reg);
  76         if (ret < 0) {
  77                 dev_err(&client->dev, "cannot write addr value");
  78                 return ret;
  79         }
  80
  81         ret = i2c_smbus_read_byte(client);
  82         if (ret < 0)
  83                 dev_err(&client->dev, "cannot read data value");
  84
  85         return ret;
  86 }
  87
  88 static inline int lidar_write_control(struct lidar_data *data, int val)
  89 {
  90         return i2c_smbus_write_byte_data(data->client, LIDAR_REG_CONTROL, val);
  91 }
  92
  93 static int lidar_read_measurement(struct lidar_data *data, u16 *reg)
  94 {
  95         int ret;
  96         int val;
  97
  98         ret = lidar_read_byte(data, LIDAR_REG_DATA_HBYTE);
  99         if (ret < 0)
 100                 return ret;
 101         val = ret << 8;
 102
 103         ret = lidar_read_byte(data, LIDAR_REG_DATA_LBYTE);
 104         if (ret < 0)
 105                 return ret;
 106
 107         val |= ret;
 108         *reg = val;
 109
 110         return 0;
 111 }
 112
 113 static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
 114 {
 115         struct i2c_client *client = data->client;
 116         int tries = 10;
 117         int ret;
 118
 119         /* start sample */
 120         ret = lidar_write_control(data, LIDAR_REG_CONTROL_ACQUIRE);
 121         if (ret < 0) {
 122                 dev_err(&client->dev, "cannot send start measurement command");
 123                 return ret;
 124         }
 125
 126         while (tries--) {
 127                 usleep_range(1000, 2000);
 128
 129                 ret = lidar_read_byte(data, LIDAR_REG_STATUS);
 130                 if (ret < 0)
 131                         break;
 132
 133                 /* return 0 since laser is likely pointed out of range */
 134                 if (ret & LIDAR_REG_STATUS_INVALID) {
 135                         *reg = 0;
 136                         ret = 0;
 137                         break;
 138                 }
 139
 140                 /* sample ready to read */
 141                 if (!(ret & LIDAR_REG_STATUS_READY)) {
 142                         ret = lidar_read_measurement(data, reg);
 143                         break;
 144                 }
 145                 ret = -EIO;
 146         }
 147
 148         return ret;
 149 }
 150
 151 static int lidar_read_raw(struct iio_dev *indio_dev,
 152                           struct iio_chan_spec const *chan,
 153                           int *val, int *val2, long mask)
 154 {
 155         struct lidar_data *data = iio_priv(indio_dev);
 156         int ret = -EINVAL;
 157
 158         mutex_lock(&indio_dev->mlock);
 159
 160         if (iio_buffer_enabled(indio_dev) && mask == IIO_CHAN_INFO_RAW) {
 161                 ret = -EBUSY;
 162                 goto error_busy;
 163         }
 164
 165         switch (mask) {
 166         case IIO_CHAN_INFO_RAW: {
 167                 u16 reg;
 168
 169                 ret = lidar_get_measurement(data, &reg);
 170                 if (!ret) {
 171                         *val = reg;
 172                         ret = IIO_VAL_INT;
 173                 }
 174                 break;
 175         }
 176         case IIO_CHAN_INFO_SCALE:
 177                 *val = 0;
 178                 *val2 = 10000;
 179                 ret = IIO_VAL_INT_PLUS_MICRO;
 180                 break;
 181         }
 182
 183 error_busy:
 184         mutex_unlock(&indio_dev->mlock);
 185
 186         return ret;
 187 }
 188
 189 static irqreturn_t lidar_trigger_handler(int irq, void *private)
 190 {
 191         struct iio_poll_func *pf = private;
 192         struct iio_dev *indio_dev = pf->indio_dev;
 193         struct lidar_data *data = iio_priv(indio_dev);
 194         int ret;
 195
 196         ret = lidar_get_measurement(data, data->buffer);
 197         if (!ret) {
 198                 iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
 199                                                    iio_get_time_ns());
 200         } else {
 201                 dev_err(&data->client->dev, "cannot read LIDAR measurement");
 202         }
 203
 204         iio_trigger_notify_done(indio_dev->trig);
 205
 206         return IRQ_HANDLED;
 207 }
 208
 209 static const struct iio_info lidar_info = {
 210         .driver_module = THIS_MODULE,
 211         .read_raw = lidar_read_raw,
 212 };
 213
 214 static int lidar_probe(struct i2c_client *client,
 215                        const struct i2c_device_id *id)
 216 {
 217         struct lidar_data *data;
 218         struct iio_dev *indio_dev;
 219         int ret;
 220
 221         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 222         if (!indio_dev)
 223                 return -ENOMEM;
 224
 225         indio_dev->info = &lidar_info;
 226         indio_dev->name = LIDAR_DRV_NAME;
 227         indio_dev->channels = lidar_channels;
 228         indio_dev->num_channels = ARRAY_SIZE(lidar_channels);
 229         indio_dev->modes = INDIO_DIRECT_MODE;
 230
 231         data = iio_priv(indio_dev);
 232         i2c_set_clientdata(client, indio_dev);
 233
 234         data->client = client;
 235         data->indio_dev = indio_dev;
 236
 237         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 238                                          lidar_trigger_handler, NULL);
 239         if (ret)
 240                 return ret;
 241
 242         ret = iio_device_register(indio_dev);
 243         if (ret)
 244                 goto error_unreg_buffer;
 245
 246         return 0;
 247
 248 error_unreg_buffer:
 249         iio_triggered_buffer_cleanup(indio_dev);
 250
 251         return ret;
 252 }
 253
 254 static int lidar_remove(struct i2c_client *client)
 255 {
 256         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 257
 258         iio_device_unregister(indio_dev);
 259         iio_triggered_buffer_cleanup(indio_dev);
 260
 261         return 0;
 262 }
 263
 264 static const struct i2c_device_id lidar_id[] = {
 265         {"lidar-lite-v2", 0},
 266         { },
 267 };
 268 MODULE_DEVICE_TABLE(i2c, lidar_id);
 269
 270 static const struct of_device_id lidar_dt_ids[] = {
 271         { .compatible = "pulsedlight,lidar-lite-v2" },
 272         { }
 273 };
 274 MODULE_DEVICE_TABLE(of, lidar_dt_ids);
 275
 276 static struct i2c_driver lidar_driver = {
 277         .driver = {
 278                 .name   = LIDAR_DRV_NAME,
 279                 .of_match_table = of_match_ptr(lidar_dt_ids),
 280         },
 281         .probe          = lidar_probe,
 282         .remove         = lidar_remove,
 283         .id_table       = lidar_id,
 284 };
 285 module_i2c_driver(lidar_driver);
 286
 287 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
 288 MODULE_DESCRIPTION("PulsedLight LIDAR sensor");
 289 MODULE_LICENSE("GPL");