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
14  * ping:  __/   \____________/                        \________________
16  *          |<->|            interrupt                interrupt
18  *                           |<---------------------->|
20  *                           .  --> one round trip of ultra sonic waves
47 						/*   ping sensors */
81 	if (gpiod_get_value(data->gpiod_ping)) {  in ping_handle_irq()
82 		data->ts_rising = now;  in ping_handle_irq()
83 		complete(&data->rising);  in ping_handle_irq()
85 		data->ts_falling = now;  in ping_handle_irq()
86 		complete(&data->falling);  in ping_handle_irq()
99 	struct platform_device *pdev = to_platform_device(data->dev);  in ping_read()
102 	 * just one read-echo-cycle can take place at a time  in ping_read()
105 	mutex_lock(&data->lock);  in ping_read()
107 	reinit_completion(&data->rising);  in ping_read()
108 	reinit_completion(&data->falling);  in ping_read()
110 	gpiod_set_value(data->gpiod_ping, 1);  in ping_read()
111 	udelay(data->cfg->trigger_pulse_us);  in ping_read()
112 	gpiod_set_value(data->gpiod_ping, 0);  in ping_read()
114 	ret = gpiod_direction_input(data->gpiod_ping);  in ping_read()
116 		mutex_unlock(&data->lock);  in ping_read()
120 	data->irqnr = gpiod_to_irq(data->gpiod_ping);  in ping_read()
121 	if (data->irqnr < 0) {  in ping_read()
122 		dev_err(data->dev, "gpiod_to_irq: %d\n", data->irqnr);  in ping_read()
123 		mutex_unlock(&data->lock);  in ping_read()
124 		return data->irqnr;  in ping_read()
127 	ret = request_irq(data->irqnr, ping_handle_irq,  in ping_read()
129 							pdev->name, indio_dev);  in ping_read()
131 		dev_err(data->dev, "request_irq: %d\n", ret);  in ping_read()
132 		mutex_unlock(&data->lock);  in ping_read()
137 	ret = wait_for_completion_killable_timeout(&data->rising, HZ/50);  in ping_read()
141 		ret = -ETIMEDOUT;  in ping_read()
146 	ret = wait_for_completion_killable_timeout(&data->falling, HZ/20);  in ping_read()
150 		ret = -ETIMEDOUT;  in ping_read()
154 	ktime_dt = ktime_sub(data->ts_falling, data->ts_rising);  in ping_read()
156 	free_irq(data->irqnr, indio_dev);  in ping_read()
158 	ret = gpiod_direction_output(data->gpiod_ping, GPIOD_OUT_LOW);  in ping_read()
160 		mutex_unlock(&data->lock);  in ping_read()
164 	mutex_unlock(&data->lock);  in ping_read()
167 	if (dt_ns > data->cfg->timeout_ns) {  in ping_read()
168 		dev_dbg(data->dev, "distance out of range: dt=%lldns\n",  in ping_read()
170 		return -EIO;  in ping_read()
176 	 * read error code of laser ping sensor and give users chance to  in ping_read()
179 	if (data->cfg->laserping_error) {  in ping_read()
181 			dev_dbg(data->dev, "target too close or to far\n");  in ping_read()
182 			return -EIO;  in ping_read()
185 			dev_dbg(data->dev, "internal sensor error\n");  in ping_read()
186 			return -EIO;  in ping_read()
189 			dev_dbg(data->dev, "internal sensor timeout\n");  in ping_read()
190 			return -EIO;  in ping_read()
206 	 * distance = ------ * ------- = ------------  in ping_read()
219 	free_irq(data->irqnr, indio_dev);  in ping_read()
220 	mutex_unlock(&data->lock);  in ping_read()
222 	if (gpiod_direction_output(data->gpiod_ping, GPIOD_OUT_LOW))  in ping_read()
223 		dev_dbg(data->dev, "error in gpiod_direction_output\n");  in ping_read()
233 	if (channel->type != IIO_DISTANCE)  in ping_read_raw()
234 		return -EINVAL;  in ping_read_raw()
252 		return -EINVAL;  in ping_read_raw()
270 	{ .compatible = "parallax,ping", .data = &pa_ping_cfg},
279 	struct device *dev = &pdev->dev;  in ping_probe()
286 		return -ENOMEM;  in ping_probe()
290 	data->dev = dev;  in ping_probe()
291 	data->cfg = of_device_get_match_data(dev);  in ping_probe()
293 	mutex_init(&data->lock);  in ping_probe()
294 	init_completion(&data->rising);  in ping_probe()
295 	init_completion(&data->falling);  in ping_probe()
297 	data->gpiod_ping = devm_gpiod_get(dev, "ping", GPIOD_OUT_LOW);  in ping_probe()
298 	if (IS_ERR(data->gpiod_ping)) {  in ping_probe()
299 		dev_err(dev, "failed to get ping-gpios: err=%ld\n",  in ping_probe()
300 						PTR_ERR(data->gpiod_ping));  in ping_probe()
301 		return PTR_ERR(data->gpiod_ping);  in ping_probe()
304 	if (gpiod_cansleep(data->gpiod_ping)) {  in ping_probe()
305 		dev_err(data->dev, "cansleep-GPIOs not supported\n");  in ping_probe()
306 		return -ENODEV;  in ping_probe()
311 	indio_dev->name = "ping";  in ping_probe()
312 	indio_dev->info = &ping_iio_info;  in ping_probe()
313 	indio_dev->modes = INDIO_DIRECT_MODE;  in ping_probe()
314 	indio_dev->channels = ping_chan_spec;  in ping_probe()
315 	indio_dev->num_channels = ARRAY_SIZE(ping_chan_spec);  in ping_probe()
323 		.name		= "ping-gpio",
330 MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
331 MODULE_DESCRIPTION("PING sensors for distance measuring using one GPIOs");
333 MODULE_ALIAS("platform:ping");