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37#include <linux/err.h>
38#include <linux/gpio/consumer.h>
39#include <linux/kernel.h>
40#include <linux/module.h>
41#include <linux/of.h>
42#include <linux/of_device.h>
43#include <linux/platform_device.h>
44#include <linux/property.h>
45#include <linux/sched.h>
46#include <linux/interrupt.h>
47#include <linux/delay.h>
48#include <linux/pm_runtime.h>
49#include <linux/iio/iio.h>
50#include <linux/iio/sysfs.h>
51
52struct srf04_cfg {
53 unsigned long trigger_pulse_us;
54};
55
56struct srf04_data {
57 struct device *dev;
58 struct gpio_desc *gpiod_trig;
59 struct gpio_desc *gpiod_echo;
60 struct gpio_desc *gpiod_power;
61 struct mutex lock;
62 int irqnr;
63 ktime_t ts_rising;
64 ktime_t ts_falling;
65 struct completion rising;
66 struct completion falling;
67 const struct srf04_cfg *cfg;
68 int startup_time_ms;
69};
70
71static const struct srf04_cfg srf04_cfg = {
72 .trigger_pulse_us = 10,
73};
74
75static const struct srf04_cfg mb_lv_cfg = {
76 .trigger_pulse_us = 20,
77};
78
79static irqreturn_t srf04_handle_irq(int irq, void *dev_id)
80{
81 struct iio_dev *indio_dev = dev_id;
82 struct srf04_data *data = iio_priv(indio_dev);
83 ktime_t now = ktime_get();
84
85 if (gpiod_get_value(data->gpiod_echo)) {
86 data->ts_rising = now;
87 complete(&data->rising);
88 } else {
89 data->ts_falling = now;
90 complete(&data->falling);
91 }
92
93 return IRQ_HANDLED;
94}
95
96static int srf04_read(struct srf04_data *data)
97{
98 int ret;
99 ktime_t ktime_dt;
100 u64 dt_ns;
101 u32 time_ns, distance_mm;
102
103 if (data->gpiod_power) {
104 ret = pm_runtime_resume_and_get(data->dev);
105 if (ret < 0)
106 return ret;
107 }
108
109
110
111
112 mutex_lock(&data->lock);
113
114 reinit_completion(&data->rising);
115 reinit_completion(&data->falling);
116
117 gpiod_set_value(data->gpiod_trig, 1);
118 udelay(data->cfg->trigger_pulse_us);
119 gpiod_set_value(data->gpiod_trig, 0);
120
121 if (data->gpiod_power) {
122 pm_runtime_mark_last_busy(data->dev);
123 pm_runtime_put_autosuspend(data->dev);
124 }
125
126
127 ret = wait_for_completion_killable_timeout(&data->rising, HZ/50);
128 if (ret < 0) {
129 mutex_unlock(&data->lock);
130 return ret;
131 } else if (ret == 0) {
132 mutex_unlock(&data->lock);
133 return -ETIMEDOUT;
134 }
135
136
137 ret = wait_for_completion_killable_timeout(&data->falling, HZ/20);
138 if (ret < 0) {
139 mutex_unlock(&data->lock);
140 return ret;
141 } else if (ret == 0) {
142 mutex_unlock(&data->lock);
143 return -ETIMEDOUT;
144 }
145
146 ktime_dt = ktime_sub(data->ts_falling, data->ts_rising);
147
148 mutex_unlock(&data->lock);
149
150 dt_ns = ktime_to_ns(ktime_dt);
151
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163
164 if (dt_ns > 40438871)
165 return -EIO;
166
167 time_ns = dt_ns;
168
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188
189 distance_mm = time_ns * 106 / 617176;
190
191 return distance_mm;
192}
193
194static int srf04_read_raw(struct iio_dev *indio_dev,
195 struct iio_chan_spec const *channel, int *val,
196 int *val2, long info)
197{
198 struct srf04_data *data = iio_priv(indio_dev);
199 int ret;
200
201 if (channel->type != IIO_DISTANCE)
202 return -EINVAL;
203
204 switch (info) {
205 case IIO_CHAN_INFO_RAW:
206 ret = srf04_read(data);
207 if (ret < 0)
208 return ret;
209 *val = ret;
210 return IIO_VAL_INT;
211 case IIO_CHAN_INFO_SCALE:
212
213
214
215
216 *val = 0;
217 *val2 = 1000;
218 return IIO_VAL_INT_PLUS_MICRO;
219 default:
220 return -EINVAL;
221 }
222}
223
224static const struct iio_info srf04_iio_info = {
225 .read_raw = srf04_read_raw,
226};
227
228static const struct iio_chan_spec srf04_chan_spec[] = {
229 {
230 .type = IIO_DISTANCE,
231 .info_mask_separate =
232 BIT(IIO_CHAN_INFO_RAW) |
233 BIT(IIO_CHAN_INFO_SCALE),
234 },
235};
236
237static const struct of_device_id of_srf04_match[] = {
238 { .compatible = "devantech,srf04", .data = &srf04_cfg},
239 { .compatible = "maxbotix,mb1000", .data = &mb_lv_cfg},
240 { .compatible = "maxbotix,mb1010", .data = &mb_lv_cfg},
241 { .compatible = "maxbotix,mb1020", .data = &mb_lv_cfg},
242 { .compatible = "maxbotix,mb1030", .data = &mb_lv_cfg},
243 { .compatible = "maxbotix,mb1040", .data = &mb_lv_cfg},
244 {},
245};
246
247MODULE_DEVICE_TABLE(of, of_srf04_match);
248
249static int srf04_probe(struct platform_device *pdev)
250{
251 struct device *dev = &pdev->dev;
252 struct srf04_data *data;
253 struct iio_dev *indio_dev;
254 int ret;
255
256 indio_dev = devm_iio_device_alloc(dev, sizeof(struct srf04_data));
257 if (!indio_dev) {
258 dev_err(dev, "failed to allocate IIO device\n");
259 return -ENOMEM;
260 }
261
262 data = iio_priv(indio_dev);
263 data->dev = dev;
264 data->cfg = of_match_device(of_srf04_match, dev)->data;
265
266 mutex_init(&data->lock);
267 init_completion(&data->rising);
268 init_completion(&data->falling);
269
270 data->gpiod_trig = devm_gpiod_get(dev, "trig", GPIOD_OUT_LOW);
271 if (IS_ERR(data->gpiod_trig)) {
272 dev_err(dev, "failed to get trig-gpios: err=%ld\n",
273 PTR_ERR(data->gpiod_trig));
274 return PTR_ERR(data->gpiod_trig);
275 }
276
277 data->gpiod_echo = devm_gpiod_get(dev, "echo", GPIOD_IN);
278 if (IS_ERR(data->gpiod_echo)) {
279 dev_err(dev, "failed to get echo-gpios: err=%ld\n",
280 PTR_ERR(data->gpiod_echo));
281 return PTR_ERR(data->gpiod_echo);
282 }
283
284 data->gpiod_power = devm_gpiod_get_optional(dev, "power",
285 GPIOD_OUT_LOW);
286 if (IS_ERR(data->gpiod_power)) {
287 dev_err(dev, "failed to get power-gpios: err=%ld\n",
288 PTR_ERR(data->gpiod_power));
289 return PTR_ERR(data->gpiod_power);
290 }
291 if (data->gpiod_power) {
292
293 if (of_property_read_u32(dev->of_node, "startup-time-ms",
294 &data->startup_time_ms))
295 data->startup_time_ms = 100;
296 dev_dbg(dev, "using power gpio: startup-time-ms=%d\n",
297 data->startup_time_ms);
298 }
299
300 if (gpiod_cansleep(data->gpiod_echo)) {
301 dev_err(data->dev, "cansleep-GPIOs not supported\n");
302 return -ENODEV;
303 }
304
305 data->irqnr = gpiod_to_irq(data->gpiod_echo);
306 if (data->irqnr < 0) {
307 dev_err(data->dev, "gpiod_to_irq: %d\n", data->irqnr);
308 return data->irqnr;
309 }
310
311 ret = devm_request_irq(dev, data->irqnr, srf04_handle_irq,
312 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
313 pdev->name, indio_dev);
314 if (ret < 0) {
315 dev_err(data->dev, "request_irq: %d\n", ret);
316 return ret;
317 }
318
319 platform_set_drvdata(pdev, indio_dev);
320
321 indio_dev->name = "srf04";
322 indio_dev->info = &srf04_iio_info;
323 indio_dev->modes = INDIO_DIRECT_MODE;
324 indio_dev->channels = srf04_chan_spec;
325 indio_dev->num_channels = ARRAY_SIZE(srf04_chan_spec);
326
327 ret = iio_device_register(indio_dev);
328 if (ret < 0) {
329 dev_err(data->dev, "iio_device_register: %d\n", ret);
330 return ret;
331 }
332
333 if (data->gpiod_power) {
334 pm_runtime_set_autosuspend_delay(data->dev, 1000);
335 pm_runtime_use_autosuspend(data->dev);
336
337 ret = pm_runtime_set_active(data->dev);
338 if (ret) {
339 dev_err(data->dev, "pm_runtime_set_active: %d\n", ret);
340 iio_device_unregister(indio_dev);
341 }
342
343 pm_runtime_enable(data->dev);
344 pm_runtime_idle(data->dev);
345 }
346
347 return ret;
348}
349
350static int srf04_remove(struct platform_device *pdev)
351{
352 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
353 struct srf04_data *data = iio_priv(indio_dev);
354
355 iio_device_unregister(indio_dev);
356
357 if (data->gpiod_power) {
358 pm_runtime_disable(data->dev);
359 pm_runtime_set_suspended(data->dev);
360 }
361
362 return 0;
363}
364
365static int __maybe_unused srf04_pm_runtime_suspend(struct device *dev)
366{
367 struct platform_device *pdev = container_of(dev,
368 struct platform_device, dev);
369 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
370 struct srf04_data *data = iio_priv(indio_dev);
371
372 gpiod_set_value(data->gpiod_power, 0);
373
374 return 0;
375}
376
377static int __maybe_unused srf04_pm_runtime_resume(struct device *dev)
378{
379 struct platform_device *pdev = container_of(dev,
380 struct platform_device, dev);
381 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
382 struct srf04_data *data = iio_priv(indio_dev);
383
384 gpiod_set_value(data->gpiod_power, 1);
385 msleep(data->startup_time_ms);
386
387 return 0;
388}
389
390static const struct dev_pm_ops srf04_pm_ops = {
391 SET_RUNTIME_PM_OPS(srf04_pm_runtime_suspend,
392 srf04_pm_runtime_resume, NULL)
393};
394
395static struct platform_driver srf04_driver = {
396 .probe = srf04_probe,
397 .remove = srf04_remove,
398 .driver = {
399 .name = "srf04-gpio",
400 .of_match_table = of_srf04_match,
401 .pm = &srf04_pm_ops,
402 },
403};
404
405module_platform_driver(srf04_driver);
406
407MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
408MODULE_DESCRIPTION("SRF04 ultrasonic sensor for distance measuring using GPIOs");
409MODULE_LICENSE("GPL");
410MODULE_ALIAS("platform:srf04");
411
