Merge branch 'fixes' into arm/soc
[linux-2.6-microblaze.git] / drivers / iio / chemical / vz89x.c
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * vz89x.c - Support for SGX Sensortech MiCS VZ89X VOC sensors
4  *
5  * Copyright (C) 2015-2018
6  * Author: Matt Ranostay <matt.ranostay@konsulko.com>
7  */
8
9 #include <linux/module.h>
10 #include <linux/mutex.h>
11 #include <linux/init.h>
12 #include <linux/i2c.h>
13 #include <linux/of.h>
14 #include <linux/of_device.h>
15
16 #include <linux/iio/iio.h>
17 #include <linux/iio/sysfs.h>
18
19 #define VZ89X_REG_MEASUREMENT           0x09
20 #define VZ89X_REG_MEASUREMENT_RD_SIZE   6
21 #define VZ89X_REG_MEASUREMENT_WR_SIZE   3
22
23 #define VZ89X_VOC_CO2_IDX               0
24 #define VZ89X_VOC_SHORT_IDX             1
25 #define VZ89X_VOC_TVOC_IDX              2
26 #define VZ89X_VOC_RESISTANCE_IDX        3
27
28 #define VZ89TE_REG_MEASUREMENT          0x0c
29 #define VZ89TE_REG_MEASUREMENT_RD_SIZE  7
30 #define VZ89TE_REG_MEASUREMENT_WR_SIZE  6
31
32 #define VZ89TE_VOC_TVOC_IDX             0
33 #define VZ89TE_VOC_CO2_IDX              1
34 #define VZ89TE_VOC_RESISTANCE_IDX       2
35
36 enum {
37         VZ89X,
38         VZ89TE,
39 };
40
41 struct vz89x_chip_data;
42
43 struct vz89x_data {
44         struct i2c_client *client;
45         const struct vz89x_chip_data *chip;
46         struct mutex lock;
47         int (*xfer)(struct vz89x_data *data, u8 cmd);
48
49         bool is_valid;
50         unsigned long last_update;
51         u8 buffer[VZ89TE_REG_MEASUREMENT_RD_SIZE];
52 };
53
54 struct vz89x_chip_data {
55         bool (*valid)(struct vz89x_data *data);
56         const struct iio_chan_spec *channels;
57         u8 num_channels;
58
59         u8 cmd;
60         u8 read_size;
61         u8 write_size;
62 };
63
64 static const struct iio_chan_spec vz89x_channels[] = {
65         {
66                 .type = IIO_CONCENTRATION,
67                 .channel2 = IIO_MOD_CO2,
68                 .modified = 1,
69                 .info_mask_separate =
70                         BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),
71                 .address = VZ89X_VOC_CO2_IDX,
72         },
73         {
74                 .type = IIO_CONCENTRATION,
75                 .channel2 = IIO_MOD_VOC,
76                 .modified = 1,
77                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
78                 .address = VZ89X_VOC_SHORT_IDX,
79                 .extend_name = "short",
80         },
81         {
82                 .type = IIO_CONCENTRATION,
83                 .channel2 = IIO_MOD_VOC,
84                 .modified = 1,
85                 .info_mask_separate =
86                         BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),
87                 .address = VZ89X_VOC_TVOC_IDX,
88         },
89         {
90                 .type = IIO_RESISTANCE,
91                 .info_mask_separate =
92                         BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
93                 .address = VZ89X_VOC_RESISTANCE_IDX,
94                 .scan_index = -1,
95                 .scan_type = {
96                         .endianness = IIO_LE,
97                 },
98         },
99 };
100
101 static const struct iio_chan_spec vz89te_channels[] = {
102         {
103                 .type = IIO_CONCENTRATION,
104                 .channel2 = IIO_MOD_VOC,
105                 .modified = 1,
106                 .info_mask_separate =
107                         BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),
108                 .address = VZ89TE_VOC_TVOC_IDX,
109         },
110
111         {
112                 .type = IIO_CONCENTRATION,
113                 .channel2 = IIO_MOD_CO2,
114                 .modified = 1,
115                 .info_mask_separate =
116                         BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),
117                 .address = VZ89TE_VOC_CO2_IDX,
118         },
119         {
120                 .type = IIO_RESISTANCE,
121                 .info_mask_separate =
122                         BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
123                 .address = VZ89TE_VOC_RESISTANCE_IDX,
124                 .scan_index = -1,
125                 .scan_type = {
126                         .endianness = IIO_BE,
127                 },
128         },
129 };
130
131 static IIO_CONST_ATTR(in_concentration_co2_scale, "0.00000698689");
132 static IIO_CONST_ATTR(in_concentration_voc_scale, "0.00000000436681223");
133
134 static struct attribute *vz89x_attributes[] = {
135         &iio_const_attr_in_concentration_co2_scale.dev_attr.attr,
136         &iio_const_attr_in_concentration_voc_scale.dev_attr.attr,
137         NULL,
138 };
139
140 static const struct attribute_group vz89x_attrs_group = {
141         .attrs = vz89x_attributes,
142 };
143
144 /*
145  * Chipset sometime updates in the middle of a reading causing it to reset the
146  * data pointer, and causing invalid reading of previous data.
147  * We can check for this by reading MSB of the resistance reading that is
148  * always zero, and by also confirming the VOC_short isn't zero.
149  */
150
151 static bool vz89x_measurement_is_valid(struct vz89x_data *data)
152 {
153         if (data->buffer[VZ89X_VOC_SHORT_IDX] == 0)
154                 return true;
155
156         return !!(data->buffer[data->chip->read_size - 1] > 0);
157 }
158
159 /* VZ89TE device has a modified CRC-8 two complement check */
160 static bool vz89te_measurement_is_valid(struct vz89x_data *data)
161 {
162         u8 crc = 0;
163         int i, sum = 0;
164
165         for (i = 0; i < (data->chip->read_size - 1); i++) {
166                 sum = crc + data->buffer[i];
167                 crc = sum;
168                 crc += sum / 256;
169         }
170
171         return !((0xff - crc) == data->buffer[data->chip->read_size - 1]);
172 }
173
174 static int vz89x_i2c_xfer(struct vz89x_data *data, u8 cmd)
175 {
176         const struct vz89x_chip_data *chip = data->chip;
177         struct i2c_client *client = data->client;
178         struct i2c_msg msg[2];
179         int ret;
180         u8 buf[6] = { cmd, 0, 0, 0, 0, 0xf3 };
181
182         msg[0].addr = client->addr;
183         msg[0].flags = client->flags;
184         msg[0].len = chip->write_size;
185         msg[0].buf  = (char *) &buf;
186
187         msg[1].addr = client->addr;
188         msg[1].flags = client->flags | I2C_M_RD;
189         msg[1].len = chip->read_size;
190         msg[1].buf = (char *) &data->buffer;
191
192         ret = i2c_transfer(client->adapter, msg, 2);
193
194         return (ret == 2) ? 0 : ret;
195 }
196
197 static int vz89x_smbus_xfer(struct vz89x_data *data, u8 cmd)
198 {
199         struct i2c_client *client = data->client;
200         int ret;
201         int i;
202
203         ret = i2c_smbus_write_word_data(client, cmd, 0);
204         if (ret < 0)
205                 return ret;
206
207         for (i = 0; i < data->chip->read_size; i++) {
208                 ret = i2c_smbus_read_byte(client);
209                 if (ret < 0)
210                         return ret;
211                 data->buffer[i] = ret;
212         }
213
214         return 0;
215 }
216
217 static int vz89x_get_measurement(struct vz89x_data *data)
218 {
219         const struct vz89x_chip_data *chip = data->chip;
220         int ret;
221
222         /* sensor can only be polled once a second max per datasheet */
223         if (!time_after(jiffies, data->last_update + HZ))
224                 return data->is_valid ? 0 : -EAGAIN;
225
226         data->is_valid = false;
227         data->last_update = jiffies;
228
229         ret = data->xfer(data, chip->cmd);
230         if (ret < 0)
231                 return ret;
232
233         ret = chip->valid(data);
234         if (ret)
235                 return -EAGAIN;
236
237         data->is_valid = true;
238
239         return 0;
240 }
241
242 static int vz89x_get_resistance_reading(struct vz89x_data *data,
243                                         struct iio_chan_spec const *chan,
244                                         int *val)
245 {
246         u8 *tmp = (u8 *) &data->buffer[chan->address];
247
248         switch (chan->scan_type.endianness) {
249         case IIO_LE:
250                 *val = le32_to_cpup((__le32 *) tmp) & GENMASK(23, 0);
251                 break;
252         case IIO_BE:
253                 *val = be32_to_cpup((__be32 *) tmp) >> 8;
254                 break;
255         default:
256                 return -EINVAL;
257         }
258
259         return 0;
260 }
261
262 static int vz89x_read_raw(struct iio_dev *indio_dev,
263                           struct iio_chan_spec const *chan, int *val,
264                           int *val2, long mask)
265 {
266         struct vz89x_data *data = iio_priv(indio_dev);
267         int ret = -EINVAL;
268
269         switch (mask) {
270         case IIO_CHAN_INFO_RAW:
271                 mutex_lock(&data->lock);
272                 ret = vz89x_get_measurement(data);
273                 mutex_unlock(&data->lock);
274
275                 if (ret)
276                         return ret;
277
278                 switch (chan->type) {
279                 case IIO_CONCENTRATION:
280                         *val = data->buffer[chan->address];
281                         return IIO_VAL_INT;
282                 case IIO_RESISTANCE:
283                         ret = vz89x_get_resistance_reading(data, chan, val);
284                         if (!ret)
285                                 return IIO_VAL_INT;
286                         break;
287                 default:
288                         return -EINVAL;
289                 }
290                 break;
291         case IIO_CHAN_INFO_SCALE:
292                 switch (chan->type) {
293                 case IIO_RESISTANCE:
294                         *val = 10;
295                         return IIO_VAL_INT;
296                 default:
297                         return -EINVAL;
298                 }
299                 break;
300         case IIO_CHAN_INFO_OFFSET:
301                 switch (chan->channel2) {
302                 case IIO_MOD_CO2:
303                         *val = 44;
304                         *val2 = 250000;
305                         return IIO_VAL_INT_PLUS_MICRO;
306                 case IIO_MOD_VOC:
307                         *val = -13;
308                         return IIO_VAL_INT;
309                 default:
310                         return -EINVAL;
311                 }
312         }
313
314         return ret;
315 }
316
317 static const struct iio_info vz89x_info = {
318         .attrs          = &vz89x_attrs_group,
319         .read_raw       = vz89x_read_raw,
320 };
321
322 static const struct vz89x_chip_data vz89x_chips[] = {
323         {
324                 .valid = vz89x_measurement_is_valid,
325
326                 .cmd = VZ89X_REG_MEASUREMENT,
327                 .read_size = VZ89X_REG_MEASUREMENT_RD_SIZE,
328                 .write_size = VZ89X_REG_MEASUREMENT_WR_SIZE,
329
330                 .channels = vz89x_channels,
331                 .num_channels = ARRAY_SIZE(vz89x_channels),
332         },
333         {
334                 .valid = vz89te_measurement_is_valid,
335
336                 .cmd = VZ89TE_REG_MEASUREMENT,
337                 .read_size = VZ89TE_REG_MEASUREMENT_RD_SIZE,
338                 .write_size = VZ89TE_REG_MEASUREMENT_WR_SIZE,
339
340                 .channels = vz89te_channels,
341                 .num_channels = ARRAY_SIZE(vz89te_channels),
342         },
343 };
344
345 static const struct of_device_id vz89x_dt_ids[] = {
346         { .compatible = "sgx,vz89x", .data = (void *) VZ89X },
347         { .compatible = "sgx,vz89te", .data = (void *) VZ89TE },
348         { }
349 };
350 MODULE_DEVICE_TABLE(of, vz89x_dt_ids);
351
352 static int vz89x_probe(struct i2c_client *client,
353                        const struct i2c_device_id *id)
354 {
355         struct iio_dev *indio_dev;
356         struct vz89x_data *data;
357         const struct of_device_id *of_id;
358         int chip_id;
359
360         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
361         if (!indio_dev)
362                 return -ENOMEM;
363         data = iio_priv(indio_dev);
364
365         if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
366                 data->xfer = vz89x_i2c_xfer;
367         else if (i2c_check_functionality(client->adapter,
368                                 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE))
369                 data->xfer = vz89x_smbus_xfer;
370         else
371                 return -EOPNOTSUPP;
372
373         of_id = of_match_device(vz89x_dt_ids, &client->dev);
374         if (!of_id)
375                 chip_id = id->driver_data;
376         else
377                 chip_id = (unsigned long)of_id->data;
378
379         i2c_set_clientdata(client, indio_dev);
380         data->client = client;
381         data->chip = &vz89x_chips[chip_id];
382         data->last_update = jiffies - HZ;
383         mutex_init(&data->lock);
384
385         indio_dev->dev.parent = &client->dev;
386         indio_dev->info = &vz89x_info;
387         indio_dev->name = dev_name(&client->dev);
388         indio_dev->modes = INDIO_DIRECT_MODE;
389
390         indio_dev->channels = data->chip->channels;
391         indio_dev->num_channels = data->chip->num_channels;
392
393         return devm_iio_device_register(&client->dev, indio_dev);
394 }
395
396 static const struct i2c_device_id vz89x_id[] = {
397         { "vz89x", VZ89X },
398         { "vz89te", VZ89TE },
399         { }
400 };
401 MODULE_DEVICE_TABLE(i2c, vz89x_id);
402
403 static struct i2c_driver vz89x_driver = {
404         .driver = {
405                 .name   = "vz89x",
406                 .of_match_table = of_match_ptr(vz89x_dt_ids),
407         },
408         .probe = vz89x_probe,
409         .id_table = vz89x_id,
410 };
411 module_i2c_driver(vz89x_driver);
412
413 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
414 MODULE_DESCRIPTION("SGX Sensortech MiCS VZ89X VOC sensors");
415 MODULE_LICENSE("GPL v2");