iio/chemical/atlas-ezo-sensor.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * atlas-ezo-sensor.c - Support for Atlas Scientific EZO sensors
0004  *
0005  * Copyright (C) 2020 Konsulko Group
0006  * Author: Matt Ranostay <matt.ranostay@konsulko.com>
0007  */
0008
0009 #include <linux/init.h>
0010 #include <linux/delay.h>
0011 #include <linux/mod_devicetable.h>
0012 #include <linux/module.h>
0013 #include <linux/mutex.h>
0014 #include <linux/property.h>
0015 #include <linux/err.h>
0016 #include <linux/i2c.h>
0017
0018 #include <linux/iio/iio.h>
0019
0020 #define ATLAS_EZO_DRV_NAME      "atlas-ezo-sensor"
0021 #define ATLAS_INT_TIME_IN_MS        950
0022 #define ATLAS_INT_HUM_TIME_IN_MS    350
0023
0024 enum {
0025     ATLAS_CO2_EZO,
0026     ATLAS_O2_EZO,
0027     ATLAS_HUM_EZO,
0028 };
0029
0030 struct atlas_ezo_device {
0031     const struct iio_chan_spec *channels;
0032     int num_channels;
0033     int delay;
0034 };
0035
0036 struct atlas_ezo_data {
0037     struct i2c_client *client;
0038     const struct atlas_ezo_device *chip;
0039
0040     /* lock to avoid multiple concurrent read calls */
0041     struct mutex lock;
0042
0043     u8 buffer[8];
0044 };
0045
0046 #define ATLAS_CONCENTRATION_CHANNEL(_modifier) \
0047     { \
0048         .type = IIO_CONCENTRATION, \
0049         .modified = 1,\
0050         .channel2 = _modifier, \
0051         .info_mask_separate = \
0052             BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), \
0053         .scan_index = 0, \
0054         .scan_type =  { \
0055             .sign = 'u', \
0056             .realbits = 32, \
0057             .storagebits = 32, \
0058             .endianness = IIO_CPU, \
0059         }, \
0060     }
0061
0062 static const struct iio_chan_spec atlas_co2_ezo_channels[] = {
0063     ATLAS_CONCENTRATION_CHANNEL(IIO_MOD_CO2),
0064 };
0065
0066 static const struct iio_chan_spec atlas_o2_ezo_channels[] = {
0067     ATLAS_CONCENTRATION_CHANNEL(IIO_MOD_O2),
0068 };
0069
0070 static const struct iio_chan_spec atlas_hum_ezo_channels[] = {
0071     {
0072         .type = IIO_HUMIDITYRELATIVE,
0073         .info_mask_separate =
0074             BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
0075         .scan_index = 0,
0076         .scan_type =  {
0077             .sign = 'u',
0078             .realbits = 32,
0079             .storagebits = 32,
0080             .endianness = IIO_CPU,
0081         },
0082     },
0083 };
0084
0085 static struct atlas_ezo_device atlas_ezo_devices[] = {
0086     [ATLAS_CO2_EZO] = {
0087         .channels = atlas_co2_ezo_channels,
0088         .num_channels = 1,
0089         .delay = ATLAS_INT_TIME_IN_MS,
0090     },
0091     [ATLAS_O2_EZO] = {
0092         .channels = atlas_o2_ezo_channels,
0093         .num_channels = 1,
0094         .delay = ATLAS_INT_TIME_IN_MS,
0095     },
0096     [ATLAS_HUM_EZO] = {
0097         .channels = atlas_hum_ezo_channels,
0098         .num_channels = 1,
0099         .delay = ATLAS_INT_HUM_TIME_IN_MS,
0100     },
0101 };
0102
0103 static void atlas_ezo_sanitize(char *buf)
0104 {
0105     char *ptr = strchr(buf, '.');
0106
0107     if (!ptr)
0108         return;
0109
0110     memmove(ptr, ptr + 1, strlen(ptr));
0111 }
0112
0113 static int atlas_ezo_read_raw(struct iio_dev *indio_dev,
0114               struct iio_chan_spec const *chan,
0115               int *val, int *val2, long mask)
0116 {
0117     struct atlas_ezo_data *data = iio_priv(indio_dev);
0118     struct i2c_client *client = data->client;
0119
0120     if (chan->type != IIO_CONCENTRATION)
0121         return -EINVAL;
0122
0123     switch (mask) {
0124     case IIO_CHAN_INFO_RAW: {
0125         int ret;
0126         long tmp;
0127
0128         mutex_lock(&data->lock);
0129
0130         tmp = i2c_smbus_write_byte(client, 'R');
0131
0132         if (tmp < 0) {
0133             mutex_unlock(&data->lock);
0134             return tmp;
0135         }
0136
0137         msleep(data->chip->delay);
0138
0139         tmp = i2c_master_recv(client, data->buffer, sizeof(data->buffer));
0140
0141         if (tmp < 0 || data->buffer[0] != 1) {
0142             mutex_unlock(&data->lock);
0143             return -EBUSY;
0144         }
0145
0146         /* removing floating point for fixed number representation */
0147         atlas_ezo_sanitize(data->buffer + 2);
0148
0149         ret = kstrtol(data->buffer + 1, 10, &tmp);
0150
0151         *val = tmp;
0152
0153         mutex_unlock(&data->lock);
0154
0155         return ret ? ret : IIO_VAL_INT;
0156     }
0157     case IIO_CHAN_INFO_SCALE:
0158         switch (chan->type) {
0159         case IIO_HUMIDITYRELATIVE:
0160             *val = 10;
0161             return IIO_VAL_INT;
0162         case IIO_CONCENTRATION:
0163             break;
0164         default:
0165             return -EINVAL;
0166         }
0167
0168         /* IIO_CONCENTRATION modifiers */
0169         switch (chan->channel2) {
0170         case IIO_MOD_CO2:
0171             *val = 0;
0172             *val2 = 100; /* 0.0001 */
0173             return IIO_VAL_INT_PLUS_MICRO;
0174         case IIO_MOD_O2:
0175             *val = 100;
0176             return IIO_VAL_INT;
0177         }
0178         return -EINVAL;
0179     }
0180
0181     return 0;
0182 }
0183
0184 static const struct iio_info atlas_info = {
0185     .read_raw = atlas_ezo_read_raw,
0186 };
0187
0188 static const struct i2c_device_id atlas_ezo_id[] = {
0189     { "atlas-co2-ezo", (kernel_ulong_t)&atlas_ezo_devices[ATLAS_CO2_EZO] },
0190     { "atlas-o2-ezo", (kernel_ulong_t)&atlas_ezo_devices[ATLAS_O2_EZO] },
0191     { "atlas-hum-ezo", (kernel_ulong_t)&atlas_ezo_devices[ATLAS_HUM_EZO] },
0192     {}
0193 };
0194 MODULE_DEVICE_TABLE(i2c, atlas_ezo_id);
0195
0196 static const struct of_device_id atlas_ezo_dt_ids[] = {
0197     { .compatible = "atlas,co2-ezo", .data = &atlas_ezo_devices[ATLAS_CO2_EZO], },
0198     { .compatible = "atlas,o2-ezo", .data = &atlas_ezo_devices[ATLAS_O2_EZO], },
0199     { .compatible = "atlas,hum-ezo", .data = &atlas_ezo_devices[ATLAS_HUM_EZO], },
0200     {}
0201 };
0202 MODULE_DEVICE_TABLE(of, atlas_ezo_dt_ids);
0203
0204 static int atlas_ezo_probe(struct i2c_client *client,
0205                const struct i2c_device_id *id)
0206 {
0207     const struct atlas_ezo_device *chip;
0208     struct atlas_ezo_data *data;
0209     struct iio_dev *indio_dev;
0210
0211     indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
0212     if (!indio_dev)
0213         return -ENOMEM;
0214
0215     if (dev_fwnode(&client->dev))
0216         chip = device_get_match_data(&client->dev);
0217     else
0218         chip = (const struct atlas_ezo_device *)id->driver_data;
0219     if (!chip)
0220         return -EINVAL;
0221
0222     indio_dev->info = &atlas_info;
0223     indio_dev->name = ATLAS_EZO_DRV_NAME;
0224     indio_dev->channels = chip->channels;
0225     indio_dev->num_channels = chip->num_channels;
0226     indio_dev->modes = INDIO_DIRECT_MODE;
0227
0228     data = iio_priv(indio_dev);
0229     data->client = client;
0230     data->chip = chip;
0231     mutex_init(&data->lock);
0232
0233     return devm_iio_device_register(&client->dev, indio_dev);
0234 };
0235
0236 static struct i2c_driver atlas_ezo_driver = {
0237     .driver = {
0238         .name   = ATLAS_EZO_DRV_NAME,
0239         .of_match_table = atlas_ezo_dt_ids,
0240     },
0241     .probe      = atlas_ezo_probe,
0242     .id_table   = atlas_ezo_id,
0243 };
0244 module_i2c_driver(atlas_ezo_driver);
0245
0246 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
0247 MODULE_DESCRIPTION("Atlas Scientific EZO sensors");
0248 MODULE_LICENSE("GPL");