1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Sensirion SPS30 particulate matter sensor i2c driver
4 *
5 * Copyright (c) 2020 Tomasz Duszynski <tomasz.duszynski@octakon.com>
6 *
7 * I2C slave address: 0x69
8 */
9 #include <asm/unaligned.h>
10 #include <linux/crc8.h>
11 #include <linux/delay.h>
12 #include <linux/device.h>
13 #include <linux/errno.h>
14 #include <linux/i2c.h>
15 #include <linux/mod_devicetable.h>
16 #include <linux/module.h>
17 #include <linux/types.h>
18
19 #include "sps30.h"
20
21 #define SPS30_I2C_CRC8_POLYNOMIAL 0x31
22 /* max number of bytes needed to store PM measurements or serial string */
23 #define SPS30_I2C_MAX_BUF_SIZE 48
24
25 DECLARE_CRC8_TABLE(sps30_i2c_crc8_table);
26
27 #define SPS30_I2C_START_MEAS 0x0010
28 #define SPS30_I2C_STOP_MEAS 0x0104
29 #define SPS30_I2C_READ_MEAS 0x0300
30 #define SPS30_I2C_MEAS_READY 0x0202
31 #define SPS30_I2C_RESET 0xd304
32 #define SPS30_I2C_CLEAN_FAN 0x5607
33 #define SPS30_I2C_PERIOD 0x8004
34 #define SPS30_I2C_READ_SERIAL 0xd033
35 #define SPS30_I2C_READ_VERSION 0xd100
36
sps30_i2c_xfer(struct sps30_state * state,unsigned char * txbuf,size_t txsize,unsigned char * rxbuf,size_t rxsize)37 static int sps30_i2c_xfer(struct sps30_state *state, unsigned char *txbuf, size_t txsize,
38 unsigned char *rxbuf, size_t rxsize)
39 {
40 struct i2c_client *client = to_i2c_client(state->dev);
41 int ret;
42
43 /*
44 * Sensor does not support repeated start so instead of
45 * sending two i2c messages in a row we just send one by one.
46 */
47 ret = i2c_master_send(client, txbuf, txsize);
48 if (ret < 0)
49 return ret;
50 if (ret != txsize)
51 return -EIO;
52
53 if (!rxsize)
54 return 0;
55
56 ret = i2c_master_recv(client, rxbuf, rxsize);
57 if (ret < 0)
58 return ret;
59 if (ret != rxsize)
60 return -EIO;
61
62 return 0;
63 }
64
sps30_i2c_command(struct sps30_state * state,u16 cmd,void * arg,size_t arg_size,void * rsp,size_t rsp_size)65 static int sps30_i2c_command(struct sps30_state *state, u16 cmd, void *arg, size_t arg_size,
66 void *rsp, size_t rsp_size)
67 {
68 /*
69 * Internally sensor stores measurements in a following manner:
70 *
71 * PM1: upper two bytes, crc8, lower two bytes, crc8
72 * PM2P5: upper two bytes, crc8, lower two bytes, crc8
73 * PM4: upper two bytes, crc8, lower two bytes, crc8
74 * PM10: upper two bytes, crc8, lower two bytes, crc8
75 *
76 * What follows next are number concentration measurements and
77 * typical particle size measurement which we omit.
78 */
79 unsigned char buf[SPS30_I2C_MAX_BUF_SIZE];
80 unsigned char *tmp;
81 unsigned char crc;
82 size_t i;
83 int ret;
84
85 put_unaligned_be16(cmd, buf);
86 i = 2;
87
88 if (rsp) {
89 /* each two bytes are followed by a crc8 */
90 rsp_size += rsp_size / 2;
91 } else {
92 tmp = arg;
93
94 while (arg_size) {
95 buf[i] = *tmp++;
96 buf[i + 1] = *tmp++;
97 buf[i + 2] = crc8(sps30_i2c_crc8_table, buf + i, 2, CRC8_INIT_VALUE);
98 arg_size -= 2;
99 i += 3;
100 }
101 }
102
103 ret = sps30_i2c_xfer(state, buf, i, buf, rsp_size);
104 if (ret)
105 return ret;
106
107 /* validate received data and strip off crc bytes */
108 tmp = rsp;
109 for (i = 0; i < rsp_size; i += 3) {
110 crc = crc8(sps30_i2c_crc8_table, buf + i, 2, CRC8_INIT_VALUE);
111 if (crc != buf[i + 2]) {
112 dev_err(state->dev, "data integrity check failed\n");
113 return -EIO;
114 }
115
116 *tmp++ = buf[i];
117 *tmp++ = buf[i + 1];
118 }
119
120 return 0;
121 }
122
sps30_i2c_start_meas(struct sps30_state * state)123 static int sps30_i2c_start_meas(struct sps30_state *state)
124 {
125 /* request BE IEEE754 formatted data */
126 unsigned char buf[] = { 0x03, 0x00 };
127
128 return sps30_i2c_command(state, SPS30_I2C_START_MEAS, buf, sizeof(buf), NULL, 0);
129 }
130
sps30_i2c_stop_meas(struct sps30_state * state)131 static int sps30_i2c_stop_meas(struct sps30_state *state)
132 {
133 return sps30_i2c_command(state, SPS30_I2C_STOP_MEAS, NULL, 0, NULL, 0);
134 }
135
sps30_i2c_reset(struct sps30_state * state)136 static int sps30_i2c_reset(struct sps30_state *state)
137 {
138 int ret;
139
140 ret = sps30_i2c_command(state, SPS30_I2C_RESET, NULL, 0, NULL, 0);
141 msleep(500);
142 /*
143 * Power-on-reset causes sensor to produce some glitch on i2c bus and
144 * some controllers end up in error state. Recover simply by placing
145 * some data on the bus, for example STOP_MEAS command, which
146 * is NOP in this case.
147 */
148 sps30_i2c_stop_meas(state);
149
150 return ret;
151 }
152
sps30_i2c_meas_ready(struct sps30_state * state)153 static bool sps30_i2c_meas_ready(struct sps30_state *state)
154 {
155 unsigned char buf[2];
156 int ret;
157
158 ret = sps30_i2c_command(state, SPS30_I2C_MEAS_READY, NULL, 0, buf, sizeof(buf));
159 if (ret)
160 return false;
161
162 return buf[1];
163 }
164
sps30_i2c_read_meas(struct sps30_state * state,__be32 * meas,size_t num)165 static int sps30_i2c_read_meas(struct sps30_state *state, __be32 *meas, size_t num)
166 {
167 /* measurements are ready within a second */
168 if (msleep_interruptible(1000))
169 return -EINTR;
170
171 if (!sps30_i2c_meas_ready(state))
172 return -ETIMEDOUT;
173
174 return sps30_i2c_command(state, SPS30_I2C_READ_MEAS, NULL, 0, meas, sizeof(num) * num);
175 }
176
sps30_i2c_clean_fan(struct sps30_state * state)177 static int sps30_i2c_clean_fan(struct sps30_state *state)
178 {
179 return sps30_i2c_command(state, SPS30_I2C_CLEAN_FAN, NULL, 0, NULL, 0);
180 }
181
sps30_i2c_read_cleaning_period(struct sps30_state * state,__be32 * period)182 static int sps30_i2c_read_cleaning_period(struct sps30_state *state, __be32 *period)
183 {
184 return sps30_i2c_command(state, SPS30_I2C_PERIOD, NULL, 0, period, sizeof(*period));
185 }
186
sps30_i2c_write_cleaning_period(struct sps30_state * state,__be32 period)187 static int sps30_i2c_write_cleaning_period(struct sps30_state *state, __be32 period)
188 {
189 return sps30_i2c_command(state, SPS30_I2C_PERIOD, &period, sizeof(period), NULL, 0);
190 }
191
sps30_i2c_show_info(struct sps30_state * state)192 static int sps30_i2c_show_info(struct sps30_state *state)
193 {
194 /* extra nul just in case */
195 unsigned char buf[32 + 1] = { 0x00 };
196 int ret;
197
198 ret = sps30_i2c_command(state, SPS30_I2C_READ_SERIAL, NULL, 0, buf, sizeof(buf) - 1);
199 if (ret)
200 return ret;
201
202 dev_info(state->dev, "serial number: %s\n", buf);
203
204 ret = sps30_i2c_command(state, SPS30_I2C_READ_VERSION, NULL, 0, buf, 2);
205 if (ret)
206 return ret;
207
208 dev_info(state->dev, "fw version: %u.%u\n", buf[0], buf[1]);
209
210 return 0;
211 }
212
213 static const struct sps30_ops sps30_i2c_ops = {
214 .start_meas = sps30_i2c_start_meas,
215 .stop_meas = sps30_i2c_stop_meas,
216 .read_meas = sps30_i2c_read_meas,
217 .reset = sps30_i2c_reset,
218 .clean_fan = sps30_i2c_clean_fan,
219 .read_cleaning_period = sps30_i2c_read_cleaning_period,
220 .write_cleaning_period = sps30_i2c_write_cleaning_period,
221 .show_info = sps30_i2c_show_info,
222 };
223
sps30_i2c_probe(struct i2c_client * client)224 static int sps30_i2c_probe(struct i2c_client *client)
225 {
226 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
227 return -EOPNOTSUPP;
228
229 crc8_populate_msb(sps30_i2c_crc8_table, SPS30_I2C_CRC8_POLYNOMIAL);
230
231 return sps30_probe(&client->dev, client->name, NULL, &sps30_i2c_ops);
232 }
233
234 static const struct i2c_device_id sps30_i2c_id[] = {
235 { "sps30" },
236 { }
237 };
238 MODULE_DEVICE_TABLE(i2c, sps30_i2c_id);
239
240 static const struct of_device_id sps30_i2c_of_match[] = {
241 { .compatible = "sensirion,sps30" },
242 { }
243 };
244 MODULE_DEVICE_TABLE(of, sps30_i2c_of_match);
245
246 static struct i2c_driver sps30_i2c_driver = {
247 .driver = {
248 .name = KBUILD_MODNAME,
249 .of_match_table = sps30_i2c_of_match,
250 },
251 .id_table = sps30_i2c_id,
252 .probe = sps30_i2c_probe,
253 };
254 module_i2c_driver(sps30_i2c_driver);
255
256 MODULE_AUTHOR("Tomasz Duszynski <tomasz.duszynski@octakon.com>");
257 MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor i2c driver");
258 MODULE_LICENSE("GPL v2");
259 MODULE_IMPORT_NS(IIO_SPS30);
260
