1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Plantower PMS7003 particulate matter sensor driver
4 *
5 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
6 */
7
8 #include <asm/unaligned.h>
9 #include <linux/completion.h>
10 #include <linux/device.h>
11 #include <linux/errno.h>
12 #include <linux/iio/buffer.h>
13 #include <linux/iio/iio.h>
14 #include <linux/iio/trigger_consumer.h>
15 #include <linux/iio/triggered_buffer.h>
16 #include <linux/jiffies.h>
17 #include <linux/kernel.h>
18 #include <linux/mod_devicetable.h>
19 #include <linux/module.h>
20 #include <linux/mutex.h>
21 #include <linux/serdev.h>
22
23 #define PMS7003_DRIVER_NAME "pms7003"
24
25 #define PMS7003_MAGIC 0x424d
26 /* last 2 data bytes hold frame checksum */
27 #define PMS7003_MAX_DATA_LENGTH 28
28 #define PMS7003_CHECKSUM_LENGTH 2
29 #define PMS7003_PM10_OFFSET 10
30 #define PMS7003_PM2P5_OFFSET 8
31 #define PMS7003_PM1_OFFSET 6
32
33 #define PMS7003_TIMEOUT msecs_to_jiffies(6000)
34 #define PMS7003_CMD_LENGTH 7
35 #define PMS7003_PM_MAX 1000
36 #define PMS7003_PM_MIN 0
37
38 enum {
39 PM1,
40 PM2P5,
41 PM10,
42 };
43
44 enum pms7003_cmd {
45 CMD_WAKEUP,
46 CMD_ENTER_PASSIVE_MODE,
47 CMD_READ_PASSIVE,
48 CMD_SLEEP,
49 };
50
51 /*
52 * commands have following format:
53 *
54 * +------+------+-----+------+-----+-----------+-----------+
55 * | 0x42 | 0x4d | cmd | 0x00 | arg | cksum msb | cksum lsb |
56 * +------+------+-----+------+-----+-----------+-----------+
57 */
58 static const u8 pms7003_cmd_tbl[][PMS7003_CMD_LENGTH] = {
59 [CMD_WAKEUP] = { 0x42, 0x4d, 0xe4, 0x00, 0x01, 0x01, 0x74 },
60 [CMD_ENTER_PASSIVE_MODE] = { 0x42, 0x4d, 0xe1, 0x00, 0x00, 0x01, 0x70 },
61 [CMD_READ_PASSIVE] = { 0x42, 0x4d, 0xe2, 0x00, 0x00, 0x01, 0x71 },
62 [CMD_SLEEP] = { 0x42, 0x4d, 0xe4, 0x00, 0x00, 0x01, 0x73 },
63 };
64
65 struct pms7003_frame {
66 u8 data[PMS7003_MAX_DATA_LENGTH];
67 u16 expected_length;
68 u16 length;
69 };
70
71 struct pms7003_state {
72 struct serdev_device *serdev;
73 struct pms7003_frame frame;
74 struct completion frame_ready;
75 struct mutex lock; /* must be held whenever state gets touched */
76 /* Used to construct scan to push to the IIO buffer */
77 struct {
78 u16 data[3]; /* PM1, PM2P5, PM10 */
79 s64 ts;
80 } scan;
81 };
82
pms7003_do_cmd(struct pms7003_state * state,enum pms7003_cmd cmd)83 static int pms7003_do_cmd(struct pms7003_state *state, enum pms7003_cmd cmd)
84 {
85 int ret;
86
87 ret = serdev_device_write(state->serdev, pms7003_cmd_tbl[cmd],
88 PMS7003_CMD_LENGTH, PMS7003_TIMEOUT);
89 if (ret < PMS7003_CMD_LENGTH)
90 return ret < 0 ? ret : -EIO;
91
92 ret = wait_for_completion_interruptible_timeout(&state->frame_ready,
93 PMS7003_TIMEOUT);
94 if (!ret)
95 ret = -ETIMEDOUT;
96
97 return ret < 0 ? ret : 0;
98 }
99
pms7003_get_pm(const u8 * data)100 static u16 pms7003_get_pm(const u8 *data)
101 {
102 return clamp_val(get_unaligned_be16(data),
103 PMS7003_PM_MIN, PMS7003_PM_MAX);
104 }
105
pms7003_trigger_handler(int irq,void * p)106 static irqreturn_t pms7003_trigger_handler(int irq, void *p)
107 {
108 struct iio_poll_func *pf = p;
109 struct iio_dev *indio_dev = pf->indio_dev;
110 struct pms7003_state *state = iio_priv(indio_dev);
111 struct pms7003_frame *frame = &state->frame;
112 int ret;
113
114 mutex_lock(&state->lock);
115 ret = pms7003_do_cmd(state, CMD_READ_PASSIVE);
116 if (ret) {
117 mutex_unlock(&state->lock);
118 goto err;
119 }
120
121 state->scan.data[PM1] =
122 pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET);
123 state->scan.data[PM2P5] =
124 pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET);
125 state->scan.data[PM10] =
126 pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET);
127 mutex_unlock(&state->lock);
128
129 iio_push_to_buffers_with_timestamp(indio_dev, &state->scan,
130 iio_get_time_ns(indio_dev));
131 err:
132 iio_trigger_notify_done(indio_dev->trig);
133
134 return IRQ_HANDLED;
135 }
136
pms7003_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)137 static int pms7003_read_raw(struct iio_dev *indio_dev,
138 struct iio_chan_spec const *chan,
139 int *val, int *val2, long mask)
140 {
141 struct pms7003_state *state = iio_priv(indio_dev);
142 struct pms7003_frame *frame = &state->frame;
143 int ret;
144
145 switch (mask) {
146 case IIO_CHAN_INFO_PROCESSED:
147 switch (chan->type) {
148 case IIO_MASSCONCENTRATION:
149 mutex_lock(&state->lock);
150 ret = pms7003_do_cmd(state, CMD_READ_PASSIVE);
151 if (ret) {
152 mutex_unlock(&state->lock);
153 return ret;
154 }
155
156 *val = pms7003_get_pm(frame->data + chan->address);
157 mutex_unlock(&state->lock);
158
159 return IIO_VAL_INT;
160 default:
161 return -EINVAL;
162 }
163 }
164
165 return -EINVAL;
166 }
167
168 static const struct iio_info pms7003_info = {
169 .read_raw = pms7003_read_raw,
170 };
171
172 #define PMS7003_CHAN(_index, _mod, _addr) { \
173 .type = IIO_MASSCONCENTRATION, \
174 .modified = 1, \
175 .channel2 = IIO_MOD_ ## _mod, \
176 .address = _addr, \
177 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
178 .scan_index = _index, \
179 .scan_type = { \
180 .sign = 'u', \
181 .realbits = 10, \
182 .storagebits = 16, \
183 .endianness = IIO_CPU, \
184 }, \
185 }
186
187 static const struct iio_chan_spec pms7003_channels[] = {
188 PMS7003_CHAN(0, PM1, PMS7003_PM1_OFFSET),
189 PMS7003_CHAN(1, PM2P5, PMS7003_PM2P5_OFFSET),
190 PMS7003_CHAN(2, PM10, PMS7003_PM10_OFFSET),
191 IIO_CHAN_SOFT_TIMESTAMP(3),
192 };
193
pms7003_calc_checksum(struct pms7003_frame * frame)194 static u16 pms7003_calc_checksum(struct pms7003_frame *frame)
195 {
196 u16 checksum = (PMS7003_MAGIC >> 8) + (u8)(PMS7003_MAGIC & 0xff) +
197 (frame->length >> 8) + (u8)frame->length;
198 int i;
199
200 for (i = 0; i < frame->length - PMS7003_CHECKSUM_LENGTH; i++)
201 checksum += frame->data[i];
202
203 return checksum;
204 }
205
pms7003_frame_is_okay(struct pms7003_frame * frame)206 static bool pms7003_frame_is_okay(struct pms7003_frame *frame)
207 {
208 int offset = frame->length - PMS7003_CHECKSUM_LENGTH;
209 u16 checksum = get_unaligned_be16(frame->data + offset);
210
211 return checksum == pms7003_calc_checksum(frame);
212 }
213
pms7003_receive_buf(struct serdev_device * serdev,const unsigned char * buf,size_t size)214 static int pms7003_receive_buf(struct serdev_device *serdev,
215 const unsigned char *buf, size_t size)
216 {
217 struct iio_dev *indio_dev = serdev_device_get_drvdata(serdev);
218 struct pms7003_state *state = iio_priv(indio_dev);
219 struct pms7003_frame *frame = &state->frame;
220 int num;
221
222 if (!frame->expected_length) {
223 u16 magic;
224
225 /* wait for SOF and data length */
226 if (size < 4)
227 return 0;
228
229 magic = get_unaligned_be16(buf);
230 if (magic != PMS7003_MAGIC)
231 return 2;
232
233 num = get_unaligned_be16(buf + 2);
234 if (num <= PMS7003_MAX_DATA_LENGTH) {
235 frame->expected_length = num;
236 frame->length = 0;
237 }
238
239 return 4;
240 }
241
242 num = min(size, (size_t)(frame->expected_length - frame->length));
243 memcpy(frame->data + frame->length, buf, num);
244 frame->length += num;
245
246 if (frame->length == frame->expected_length) {
247 if (pms7003_frame_is_okay(frame))
248 complete(&state->frame_ready);
249
250 frame->expected_length = 0;
251 }
252
253 return num;
254 }
255
256 static const struct serdev_device_ops pms7003_serdev_ops = {
257 .receive_buf = pms7003_receive_buf,
258 .write_wakeup = serdev_device_write_wakeup,
259 };
260
pms7003_stop(void * data)261 static void pms7003_stop(void *data)
262 {
263 struct pms7003_state *state = data;
264
265 pms7003_do_cmd(state, CMD_SLEEP);
266 }
267
268 static const unsigned long pms7003_scan_masks[] = { 0x07, 0x00 };
269
pms7003_probe(struct serdev_device * serdev)270 static int pms7003_probe(struct serdev_device *serdev)
271 {
272 struct pms7003_state *state;
273 struct iio_dev *indio_dev;
274 int ret;
275
276 indio_dev = devm_iio_device_alloc(&serdev->dev, sizeof(*state));
277 if (!indio_dev)
278 return -ENOMEM;
279
280 state = iio_priv(indio_dev);
281 serdev_device_set_drvdata(serdev, indio_dev);
282 state->serdev = serdev;
283 indio_dev->info = &pms7003_info;
284 indio_dev->name = PMS7003_DRIVER_NAME;
285 indio_dev->channels = pms7003_channels;
286 indio_dev->num_channels = ARRAY_SIZE(pms7003_channels);
287 indio_dev->modes = INDIO_DIRECT_MODE;
288 indio_dev->available_scan_masks = pms7003_scan_masks;
289
290 mutex_init(&state->lock);
291 init_completion(&state->frame_ready);
292
293 serdev_device_set_client_ops(serdev, &pms7003_serdev_ops);
294 ret = devm_serdev_device_open(&serdev->dev, serdev);
295 if (ret)
296 return ret;
297
298 serdev_device_set_baudrate(serdev, 9600);
299 serdev_device_set_flow_control(serdev, false);
300
301 ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
302 if (ret)
303 return ret;
304
305 ret = pms7003_do_cmd(state, CMD_WAKEUP);
306 if (ret) {
307 dev_err(&serdev->dev, "failed to wakeup sensor\n");
308 return ret;
309 }
310
311 ret = pms7003_do_cmd(state, CMD_ENTER_PASSIVE_MODE);
312 if (ret) {
313 dev_err(&serdev->dev, "failed to enter passive mode\n");
314 return ret;
315 }
316
317 ret = devm_add_action_or_reset(&serdev->dev, pms7003_stop, state);
318 if (ret)
319 return ret;
320
321 ret = devm_iio_triggered_buffer_setup(&serdev->dev, indio_dev, NULL,
322 pms7003_trigger_handler, NULL);
323 if (ret)
324 return ret;
325
326 return devm_iio_device_register(&serdev->dev, indio_dev);
327 }
328
329 static const struct of_device_id pms7003_of_match[] = {
330 { .compatible = "plantower,pms1003" },
331 { .compatible = "plantower,pms3003" },
332 { .compatible = "plantower,pms5003" },
333 { .compatible = "plantower,pms6003" },
334 { .compatible = "plantower,pms7003" },
335 { .compatible = "plantower,pmsa003" },
336 { }
337 };
338 MODULE_DEVICE_TABLE(of, pms7003_of_match);
339
340 static struct serdev_device_driver pms7003_driver = {
341 .driver = {
342 .name = PMS7003_DRIVER_NAME,
343 .of_match_table = pms7003_of_match,
344 },
345 .probe = pms7003_probe,
346 };
347 module_serdev_device_driver(pms7003_driver);
348
349 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
350 MODULE_DESCRIPTION("Plantower PMS7003 particulate matter sensor driver");
351 MODULE_LICENSE("GPL v2");
352