1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * pulsedlight-lidar-lite-v2.c - Support for PulsedLight LIDAR sensor
4  *
5  * Copyright (C) 2015, 2017-2018
6  * Author: Matt Ranostay <matt.ranostay@konsulko.com>
7  *
8  * TODO: interrupt mode, and signal strength reporting
9  */
10 
11 #include <linux/err.h>
12 #include <linux/init.h>
13 #include <linux/i2c.h>
14 #include <linux/delay.h>
15 #include <linux/module.h>
16 #include <linux/mod_devicetable.h>
17 #include <linux/pm_runtime.h>
18 #include <linux/iio/iio.h>
19 #include <linux/iio/sysfs.h>
20 #include <linux/iio/buffer.h>
21 #include <linux/iio/trigger.h>
22 #include <linux/iio/triggered_buffer.h>
23 #include <linux/iio/trigger_consumer.h>
24 
25 #define LIDAR_REG_CONTROL		0x00
26 #define LIDAR_REG_CONTROL_ACQUIRE	BIT(2)
27 
28 #define LIDAR_REG_STATUS		0x01
29 #define LIDAR_REG_STATUS_INVALID	BIT(3)
30 #define LIDAR_REG_STATUS_READY		BIT(0)
31 
32 #define LIDAR_REG_DATA_HBYTE		0x0f
33 #define LIDAR_REG_DATA_LBYTE		0x10
34 #define LIDAR_REG_DATA_WORD_READ	BIT(7)
35 
36 #define LIDAR_REG_PWR_CONTROL	0x65
37 
38 #define LIDAR_DRV_NAME "lidar"
39 
40 struct lidar_data {
41 	struct iio_dev *indio_dev;
42 	struct i2c_client *client;
43 
44 	int (*xfer)(struct lidar_data *data, u8 reg, u8 *val, int len);
45 	int i2c_enabled;
46 
47 	/* Ensure timestamp is naturally aligned */
48 	struct {
49 		u16 chan;
50 		s64 timestamp __aligned(8);
51 	} scan;
52 };
53 
54 static const struct iio_chan_spec lidar_channels[] = {
55 	{
56 		.type = IIO_DISTANCE,
57 		.info_mask_separate =
58 			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
59 		.scan_index = 0,
60 		.scan_type = {
61 			.sign = 'u',
62 			.realbits = 16,
63 			.storagebits = 16,
64 		},
65 	},
66 	IIO_CHAN_SOFT_TIMESTAMP(1),
67 };
68 
69 static int lidar_i2c_xfer(struct lidar_data *data, u8 reg, u8 *val, int len)
70 {
71 	struct i2c_client *client = data->client;
72 	struct i2c_msg msg[2];
73 	int ret;
74 
75 	msg[0].addr = client->addr;
76 	msg[0].flags = client->flags | I2C_M_STOP;
77 	msg[0].len = 1;
78 	msg[0].buf  = (char *) &reg;
79 
80 	msg[1].addr = client->addr;
81 	msg[1].flags = client->flags | I2C_M_RD;
82 	msg[1].len = len;
83 	msg[1].buf = (char *) val;
84 
85 	ret = i2c_transfer(client->adapter, msg, 2);
86 
87 	return (ret == 2) ? 0 : -EIO;
88 }
89 
90 static int lidar_smbus_xfer(struct lidar_data *data, u8 reg, u8 *val, int len)
91 {
92 	struct i2c_client *client = data->client;
93 	int ret;
94 
95 	/*
96 	 * Device needs a STOP condition between address write, and data read
97 	 * so in turn i2c_smbus_read_byte_data cannot be used
98 	 */
99 
100 	while (len--) {
101 		ret = i2c_smbus_write_byte(client, reg++);
102 		if (ret < 0) {
103 			dev_err(&client->dev, "cannot write addr value");
104 			return ret;
105 		}
106 
107 		ret = i2c_smbus_read_byte(client);
108 		if (ret < 0) {
109 			dev_err(&client->dev, "cannot read data value");
110 			return ret;
111 		}
112 
113 		*(val++) = ret;
114 	}
115 
116 	return 0;
117 }
118 
119 static int lidar_read_byte(struct lidar_data *data, u8 reg)
120 {
121 	int ret;
122 	u8 val;
123 
124 	ret = data->xfer(data, reg, &val, 1);
125 	if (ret < 0)
126 		return ret;
127 
128 	return val;
129 }
130 
131 static inline int lidar_write_control(struct lidar_data *data, int val)
132 {
133 	return i2c_smbus_write_byte_data(data->client, LIDAR_REG_CONTROL, val);
134 }
135 
136 static inline int lidar_write_power(struct lidar_data *data, int val)
137 {
138 	return i2c_smbus_write_byte_data(data->client,
139 					 LIDAR_REG_PWR_CONTROL, val);
140 }
141 
142 static int lidar_read_measurement(struct lidar_data *data, u16 *reg)
143 {
144 	__be16 value;
145 	int ret = data->xfer(data, LIDAR_REG_DATA_HBYTE |
146 			(data->i2c_enabled ? LIDAR_REG_DATA_WORD_READ : 0),
147 			(u8 *) &value, 2);
148 
149 	if (!ret)
150 		*reg = be16_to_cpu(value);
151 
152 	return ret;
153 }
154 
155 static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
156 {
157 	struct i2c_client *client = data->client;
158 	int tries = 10;
159 	int ret;
160 
161 	ret = pm_runtime_resume_and_get(&client->dev);
162 	if (ret < 0)
163 		return ret;
164 
165 	/* start sample */
166 	ret = lidar_write_control(data, LIDAR_REG_CONTROL_ACQUIRE);
167 	if (ret < 0) {
168 		dev_err(&client->dev, "cannot send start measurement command");
169 		pm_runtime_put_noidle(&client->dev);
170 		return ret;
171 	}
172 
173 	while (tries--) {
174 		usleep_range(1000, 2000);
175 
176 		ret = lidar_read_byte(data, LIDAR_REG_STATUS);
177 		if (ret < 0)
178 			break;
179 
180 		/* return -EINVAL since laser is likely pointed out of range */
181 		if (ret & LIDAR_REG_STATUS_INVALID) {
182 			*reg = 0;
183 			ret = -EINVAL;
184 			break;
185 		}
186 
187 		/* sample ready to read */
188 		if (!(ret & LIDAR_REG_STATUS_READY)) {
189 			ret = lidar_read_measurement(data, reg);
190 			break;
191 		}
192 		ret = -EIO;
193 	}
194 	pm_runtime_mark_last_busy(&client->dev);
195 	pm_runtime_put_autosuspend(&client->dev);
196 
197 	return ret;
198 }
199 
200 static int lidar_read_raw(struct iio_dev *indio_dev,
201 			  struct iio_chan_spec const *chan,
202 			  int *val, int *val2, long mask)
203 {
204 	struct lidar_data *data = iio_priv(indio_dev);
205 	int ret = -EINVAL;
206 
207 	switch (mask) {
208 	case IIO_CHAN_INFO_RAW: {
209 		u16 reg;
210 
211 		if (iio_device_claim_direct_mode(indio_dev))
212 			return -EBUSY;
213 
214 		ret = lidar_get_measurement(data, &reg);
215 		if (!ret) {
216 			*val = reg;
217 			ret = IIO_VAL_INT;
218 		}
219 		iio_device_release_direct_mode(indio_dev);
220 		break;
221 	}
222 	case IIO_CHAN_INFO_SCALE:
223 		*val = 0;
224 		*val2 = 10000;
225 		ret = IIO_VAL_INT_PLUS_MICRO;
226 		break;
227 	}
228 
229 	return ret;
230 }
231 
232 static irqreturn_t lidar_trigger_handler(int irq, void *private)
233 {
234 	struct iio_poll_func *pf = private;
235 	struct iio_dev *indio_dev = pf->indio_dev;
236 	struct lidar_data *data = iio_priv(indio_dev);
237 	int ret;
238 
239 	ret = lidar_get_measurement(data, &data->scan.chan);
240 	if (!ret) {
241 		iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
242 						   iio_get_time_ns(indio_dev));
243 	} else if (ret != -EINVAL) {
244 		dev_err(&data->client->dev, "cannot read LIDAR measurement");
245 	}
246 
247 	iio_trigger_notify_done(indio_dev->trig);
248 
249 	return IRQ_HANDLED;
250 }
251 
252 static const struct iio_info lidar_info = {
253 	.read_raw = lidar_read_raw,
254 };
255 
256 static int lidar_probe(struct i2c_client *client)
257 {
258 	struct lidar_data *data;
259 	struct iio_dev *indio_dev;
260 	int ret;
261 
262 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
263 	if (!indio_dev)
264 		return -ENOMEM;
265 	data = iio_priv(indio_dev);
266 
267 	if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
268 		data->xfer = lidar_i2c_xfer;
269 		data->i2c_enabled = 1;
270 	} else if (i2c_check_functionality(client->adapter,
271 				I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE))
272 		data->xfer = lidar_smbus_xfer;
273 	else
274 		return -EOPNOTSUPP;
275 
276 	indio_dev->info = &lidar_info;
277 	indio_dev->name = LIDAR_DRV_NAME;
278 	indio_dev->channels = lidar_channels;
279 	indio_dev->num_channels = ARRAY_SIZE(lidar_channels);
280 	indio_dev->modes = INDIO_DIRECT_MODE;
281 
282 	i2c_set_clientdata(client, indio_dev);
283 
284 	data->client = client;
285 	data->indio_dev = indio_dev;
286 
287 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
288 					 lidar_trigger_handler, NULL);
289 	if (ret)
290 		return ret;
291 
292 	ret = iio_device_register(indio_dev);
293 	if (ret)
294 		goto error_unreg_buffer;
295 
296 	pm_runtime_set_autosuspend_delay(&client->dev, 1000);
297 	pm_runtime_use_autosuspend(&client->dev);
298 
299 	ret = pm_runtime_set_active(&client->dev);
300 	if (ret)
301 		goto error_unreg_buffer;
302 	pm_runtime_enable(&client->dev);
303 	pm_runtime_idle(&client->dev);
304 
305 	return 0;
306 
307 error_unreg_buffer:
308 	iio_triggered_buffer_cleanup(indio_dev);
309 
310 	return ret;
311 }
312 
313 static void lidar_remove(struct i2c_client *client)
314 {
315 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
316 
317 	iio_device_unregister(indio_dev);
318 	iio_triggered_buffer_cleanup(indio_dev);
319 
320 	pm_runtime_disable(&client->dev);
321 	pm_runtime_set_suspended(&client->dev);
322 }
323 
324 static const struct i2c_device_id lidar_id[] = {
325 	{"lidar-lite-v2", 0},
326 	{"lidar-lite-v3", 0},
327 	{ },
328 };
329 MODULE_DEVICE_TABLE(i2c, lidar_id);
330 
331 static const struct of_device_id lidar_dt_ids[] = {
332 	{ .compatible = "pulsedlight,lidar-lite-v2" },
333 	{ .compatible = "grmn,lidar-lite-v3" },
334 	{ }
335 };
336 MODULE_DEVICE_TABLE(of, lidar_dt_ids);
337 
338 static int lidar_pm_runtime_suspend(struct device *dev)
339 {
340 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
341 	struct lidar_data *data = iio_priv(indio_dev);
342 
343 	return lidar_write_power(data, 0x0f);
344 }
345 
346 static int lidar_pm_runtime_resume(struct device *dev)
347 {
348 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
349 	struct lidar_data *data = iio_priv(indio_dev);
350 	int ret = lidar_write_power(data, 0);
351 
352 	/* regulator and FPGA needs settling time */
353 	usleep_range(15000, 20000);
354 
355 	return ret;
356 }
357 
358 static const struct dev_pm_ops lidar_pm_ops = {
359 	RUNTIME_PM_OPS(lidar_pm_runtime_suspend, lidar_pm_runtime_resume, NULL)
360 };
361 
362 static struct i2c_driver lidar_driver = {
363 	.driver = {
364 		.name	= LIDAR_DRV_NAME,
365 		.of_match_table	= lidar_dt_ids,
366 		.pm	= pm_ptr(&lidar_pm_ops),
367 	},
368 	.probe		= lidar_probe,
369 	.remove		= lidar_remove,
370 	.id_table	= lidar_id,
371 };
372 module_i2c_driver(lidar_driver);
373 
374 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
375 MODULE_DESCRIPTION("PulsedLight LIDAR sensor");
376 MODULE_LICENSE("GPL");
377