1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * PING: ultrasonic sensor for distance measuring by using only one GPIOs
5  * Copyright (c) 2019 Andreas Klinger <ak@it-klinger.de>
8  * http://parallax.com/sites/default/files/downloads/28041-LaserPING-2m-Rangefinder-Guide.pdf
9  * http://parallax.com/sites/default/files/downloads/28015-PING-Documentation-v1.6.pdf
16  *          |<->|            interrupt                interrupt
18  *                           |<---------------------->|
20  *                           .  --> one round trip of ultra sonic waves
27  * echo:  __________________________________/ \_/ \_/ \________________
80 	if (gpiod_get_value(data->gpiod_ping)) {  in ping_handle_irq()
81 		data->ts_rising = now;  in ping_handle_irq()
82 		complete(&data->rising);  in ping_handle_irq()
84 		data->ts_falling = now;  in ping_handle_irq()
85 		complete(&data->falling);  in ping_handle_irq()
98 	struct platform_device *pdev = to_platform_device(data->dev);  in ping_read()
101 	 * just one read-echo-cycle can take place at a time  in ping_read()
104 	mutex_lock(&data->lock);  in ping_read()
106 	reinit_completion(&data->rising);  in ping_read()
107 	reinit_completion(&data->falling);  in ping_read()
109 	gpiod_set_value(data->gpiod_ping, 1);  in ping_read()
110 	udelay(data->cfg->trigger_pulse_us);  in ping_read()
111 	gpiod_set_value(data->gpiod_ping, 0);  in ping_read()
113 	ret = gpiod_direction_input(data->gpiod_ping);  in ping_read()
115 		mutex_unlock(&data->lock);  in ping_read()
119 	data->irqnr = gpiod_to_irq(data->gpiod_ping);  in ping_read()
120 	if (data->irqnr < 0) {  in ping_read()
121 		dev_err(data->dev, "gpiod_to_irq: %d\n", data->irqnr);  in ping_read()
122 		mutex_unlock(&data->lock);  in ping_read()
123 		return data->irqnr;  in ping_read()
126 	ret = request_irq(data->irqnr, ping_handle_irq,  in ping_read()
128 							pdev->name, indio_dev);  in ping_read()
130 		dev_err(data->dev, "request_irq: %d\n", ret);  in ping_read()
131 		mutex_unlock(&data->lock);  in ping_read()
135 	/* it should not take more than 20 ms until echo is rising */  in ping_read()
136 	ret = wait_for_completion_killable_timeout(&data->rising, HZ/50);  in ping_read()
140 		ret = -ETIMEDOUT;  in ping_read()
144 	/* it cannot take more than 50 ms until echo is falling */  in ping_read()
145 	ret = wait_for_completion_killable_timeout(&data->falling, HZ/20);  in ping_read()
149 		ret = -ETIMEDOUT;  in ping_read()
153 	ktime_dt = ktime_sub(data->ts_falling, data->ts_rising);  in ping_read()
155 	free_irq(data->irqnr, indio_dev);  in ping_read()
157 	ret = gpiod_direction_output(data->gpiod_ping, GPIOD_OUT_LOW);  in ping_read()
159 		mutex_unlock(&data->lock);  in ping_read()
163 	mutex_unlock(&data->lock);  in ping_read()
166 	if (dt_ns > data->cfg->timeout_ns) {  in ping_read()
167 		dev_dbg(data->dev, "distance out of range: dt=%lldns\n",  in ping_read()
169 		return -EIO;  in ping_read()
178 	if (data->cfg->laserping_error) {  in ping_read()
180 			dev_dbg(data->dev, "target too close or to far\n");  in ping_read()
181 			return -EIO;  in ping_read()
184 			dev_dbg(data->dev, "internal sensor error\n");  in ping_read()
185 			return -EIO;  in ping_read()
188 			dev_dbg(data->dev, "internal sensor timeout\n");  in ping_read()
189 			return -EIO;  in ping_read()
205 	 * distance = ------ * ------- = ------------  in ping_read()
218 	free_irq(data->irqnr, indio_dev);  in ping_read()
219 	mutex_unlock(&data->lock);  in ping_read()
221 	if (gpiod_direction_output(data->gpiod_ping, GPIOD_OUT_LOW))  in ping_read()
222 		dev_dbg(data->dev, "error in gpiod_direction_output\n");  in ping_read()
232 	if (channel->type != IIO_DISTANCE)  in ping_read_raw()
233 		return -EINVAL;  in ping_read_raw()
251 		return -EINVAL;  in ping_read_raw()
278 	struct device *dev = &pdev->dev;  in ping_probe()
285 		return -ENOMEM;  in ping_probe()
289 	data->dev = dev;  in ping_probe()
290 	data->cfg = device_get_match_data(dev);  in ping_probe()
292 	mutex_init(&data->lock);  in ping_probe()
293 	init_completion(&data->rising);  in ping_probe()
294 	init_completion(&data->falling);  in ping_probe()
296 	data->gpiod_ping = devm_gpiod_get(dev, "ping", GPIOD_OUT_LOW);  in ping_probe()
297 	if (IS_ERR(data->gpiod_ping)) {  in ping_probe()
298 		dev_err(dev, "failed to get ping-gpios: err=%ld\n",  in ping_probe()
299 						PTR_ERR(data->gpiod_ping));  in ping_probe()
300 		return PTR_ERR(data->gpiod_ping);  in ping_probe()
303 	if (gpiod_cansleep(data->gpiod_ping)) {  in ping_probe()
304 		dev_err(data->dev, "cansleep-GPIOs not supported\n");  in ping_probe()
305 		return -ENODEV;  in ping_probe()
310 	indio_dev->name = "ping";  in ping_probe()
311 	indio_dev->info = &ping_iio_info;  in ping_probe()
312 	indio_dev->modes = INDIO_DIRECT_MODE;  in ping_probe()
313 	indio_dev->channels = ping_chan_spec;  in ping_probe()
314 	indio_dev->num_channels = ARRAY_SIZE(ping_chan_spec);  in ping_probe()
322 		.name		= "ping-gpio",
329 MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
330 MODULE_DESCRIPTION("PING sensors for distance measuring using one GPIOs");