drivers/iio/proximity/mb1232.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * mb1232.c - Support for MaxBotix I2CXL-MaxSonar-EZ series ultrasonic
   4  *   ranger with i2c interface
   5  * actually tested with mb1232 type
   6  *
   7  * Copyright (c) 2019 Andreas Klinger <ak@it-klinger.de>
   8  *
   9  * For details about the device see:
  10  * https://www.maxbotix.com/documents/I2CXL-MaxSonar-EZ_Datasheet.pdf
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/i2c.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/delay.h>
  17 #include <linux/module.h>
  18 #include <linux/bitops.h>
  19 #include <linux/iio/iio.h>
  20 #include <linux/iio/sysfs.h>
  21 #include <linux/iio/buffer.h>
  22 #include <linux/iio/trigger_consumer.h>
  23 #include <linux/iio/triggered_buffer.h>
  24
  25 /* registers of MaxSonar device */
  26 #define MB1232_RANGE_COMMAND    0x51    /* Command for reading range */
  27 #define MB1232_ADDR_UNLOCK_1    0xAA    /* Command 1 for changing address */
  28 #define MB1232_ADDR_UNLOCK_2    0xA5    /* Command 2 for changing address */
  29
  30 struct mb1232_data {
  31         struct i2c_client       *client;
  32
  33         struct mutex            lock;
  34
  35         /*
  36          * optionally a gpio can be used to announce when ranging has
  37          * finished
  38          * since we are just using the falling trigger of it we request
  39          * only the interrupt for announcing when data is ready to be read
  40          */
  41         struct completion       ranging;
  42         int                     irqnr;
  43         /* Ensure correct alignment of data to push to IIO buffer */
  44         struct {
  45                 s16 distance;
  46                 s64 ts __aligned(8);
  47         } scan;
  48 };
  49
  50 static irqreturn_t mb1232_handle_irq(int irq, void *dev_id)
  51 {
  52         struct iio_dev *indio_dev = dev_id;
  53         struct mb1232_data *data = iio_priv(indio_dev);
  54
  55         complete(&data->ranging);
  56
  57         return IRQ_HANDLED;
  58 }
  59
  60 static s16 mb1232_read_distance(struct mb1232_data *data)
  61 {
  62         struct i2c_client *client = data->client;
  63         int ret;
  64         s16 distance;
  65         __be16 buf;
  66
  67         mutex_lock(&data->lock);
  68
  69         reinit_completion(&data->ranging);
  70
  71         ret = i2c_smbus_write_byte(client, MB1232_RANGE_COMMAND);
  72         if (ret < 0) {
  73                 dev_err(&client->dev, "write command - err: %d\n", ret);
  74                 goto error_unlock;
  75         }
  76
  77         if (data->irqnr >= 0) {
  78                 /* it cannot take more than 100 ms */
  79                 ret = wait_for_completion_killable_timeout(&data->ranging,
  80                                                                         HZ/10);
  81                 if (ret < 0)
  82                         goto error_unlock;
  83                 else if (ret == 0) {
  84                         ret = -ETIMEDOUT;
  85                         goto error_unlock;
  86                 }
  87         } else {
  88                 /* use simple sleep if announce irq is not connected */
  89                 msleep(15);
  90         }
  91
  92         ret = i2c_master_recv(client, (char *)&buf, sizeof(buf));
  93         if (ret < 0) {
  94                 dev_err(&client->dev, "i2c_master_recv: ret=%d\n", ret);
  95                 goto error_unlock;
  96         }
  97
  98         distance = __be16_to_cpu(buf);
  99         /* check for not returning misleading error codes */
 100         if (distance < 0) {
 101                 dev_err(&client->dev, "distance=%d\n", distance);
 102                 ret = -EINVAL;
 103                 goto error_unlock;
 104         }
 105
 106         mutex_unlock(&data->lock);
 107
 108         return distance;
 109
 110 error_unlock:
 111         mutex_unlock(&data->lock);
 112
 113         return ret;
 114 }
 115
 116 static irqreturn_t mb1232_trigger_handler(int irq, void *p)
 117 {
 118         struct iio_poll_func *pf = p;
 119         struct iio_dev *indio_dev = pf->indio_dev;
 120         struct mb1232_data *data = iio_priv(indio_dev);
 121
 122         data->scan.distance = mb1232_read_distance(data);
 123         if (data->scan.distance < 0)
 124                 goto err;
 125
 126         iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 127                                            pf->timestamp);
 128
 129 err:
 130         iio_trigger_notify_done(indio_dev->trig);
 131         return IRQ_HANDLED;
 132 }
 133
 134 static int mb1232_read_raw(struct iio_dev *indio_dev,
 135                             struct iio_chan_spec const *channel, int *val,
 136                             int *val2, long mask)
 137 {
 138         struct mb1232_data *data = iio_priv(indio_dev);
 139         int ret;
 140
 141         if (channel->type != IIO_DISTANCE)
 142                 return -EINVAL;
 143
 144         switch (mask) {
 145         case IIO_CHAN_INFO_RAW:
 146                 ret = mb1232_read_distance(data);
 147                 if (ret < 0)
 148                         return ret;
 149                 *val = ret;
 150                 return IIO_VAL_INT;
 151         case IIO_CHAN_INFO_SCALE:
 152                 /* 1 LSB is 1 cm */
 153                 *val = 0;
 154                 *val2 = 10000;
 155                 return IIO_VAL_INT_PLUS_MICRO;
 156         default:
 157                 return -EINVAL;
 158         }
 159 }
 160
 161 static const struct iio_chan_spec mb1232_channels[] = {
 162         {
 163                 .type = IIO_DISTANCE,
 164                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 165                                       BIT(IIO_CHAN_INFO_SCALE),
 166                 .scan_index = 0,
 167                 .scan_type = {
 168                         .sign = 's',
 169                         .realbits = 16,
 170                         .storagebits = 16,
 171                         .endianness = IIO_CPU,
 172                 },
 173         },
 174         IIO_CHAN_SOFT_TIMESTAMP(1),
 175 };
 176
 177 static const struct iio_info mb1232_info = {
 178         .read_raw = mb1232_read_raw,
 179 };
 180
 181 static int mb1232_probe(struct i2c_client *client,
 182                                          const struct i2c_device_id *id)
 183 {
 184         struct iio_dev *indio_dev;
 185         struct mb1232_data *data;
 186         int ret;
 187         struct device *dev = &client->dev;
 188
 189         if (!i2c_check_functionality(client->adapter,
 190                                         I2C_FUNC_SMBUS_READ_BYTE |
 191                                         I2C_FUNC_SMBUS_WRITE_BYTE))
 192                 return -ENODEV;
 193
 194         indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 195         if (!indio_dev)
 196                 return -ENOMEM;
 197
 198         data = iio_priv(indio_dev);
 199         i2c_set_clientdata(client, indio_dev);
 200         data->client = client;
 201
 202         indio_dev->info = &mb1232_info;
 203         indio_dev->name = id->name;
 204         indio_dev->modes = INDIO_DIRECT_MODE;
 205         indio_dev->channels = mb1232_channels;
 206         indio_dev->num_channels = ARRAY_SIZE(mb1232_channels);
 207
 208         mutex_init(&data->lock);
 209
 210         init_completion(&data->ranging);
 211
 212         data->irqnr = irq_of_parse_and_map(dev->of_node, 0);
 213         if (data->irqnr <= 0) {
 214                 /* usage of interrupt is optional */
 215                 data->irqnr = -1;
 216         } else {
 217                 ret = devm_request_irq(dev, data->irqnr, mb1232_handle_irq,
 218                                 IRQF_TRIGGER_FALLING, id->name, indio_dev);
 219                 if (ret < 0) {
 220                         dev_err(dev, "request_irq: %d\n", ret);
 221                         return ret;
 222                 }
 223         }
 224
 225         ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
 226                         iio_pollfunc_store_time, mb1232_trigger_handler, NULL);
 227         if (ret < 0) {
 228                 dev_err(dev, "setup of iio triggered buffer failed\n");
 229                 return ret;
 230         }
 231
 232         return devm_iio_device_register(dev, indio_dev);
 233 }
 234
 235 static const struct of_device_id of_mb1232_match[] = {
 236         { .compatible = "maxbotix,mb1202", },
 237         { .compatible = "maxbotix,mb1212", },
 238         { .compatible = "maxbotix,mb1222", },
 239         { .compatible = "maxbotix,mb1232", },
 240         { .compatible = "maxbotix,mb1242", },
 241         { .compatible = "maxbotix,mb7040", },
 242         { .compatible = "maxbotix,mb7137", },
 243         {},
 244 };
 245
 246 MODULE_DEVICE_TABLE(of, of_mb1232_match);
 247
 248 static const struct i2c_device_id mb1232_id[] = {
 249         { "maxbotix-mb1202", },
 250         { "maxbotix-mb1212", },
 251         { "maxbotix-mb1222", },
 252         { "maxbotix-mb1232", },
 253         { "maxbotix-mb1242", },
 254         { "maxbotix-mb7040", },
 255         { "maxbotix-mb7137", },
 256         { }
 257 };
 258 MODULE_DEVICE_TABLE(i2c, mb1232_id);
 259
 260 static struct i2c_driver mb1232_driver = {
 261         .driver = {
 262                 .name   = "maxbotix-mb1232",
 263                 .of_match_table = of_mb1232_match,
 264         },
 265         .probe = mb1232_probe,
 266         .id_table = mb1232_id,
 267 };
 268 module_i2c_driver(mb1232_driver);
 269
 270 MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
 271 MODULE_DESCRIPTION("Maxbotix I2CXL-MaxSonar i2c ultrasonic ranger driver");
 272 MODULE_LICENSE("GPL");