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