linux/drivers/iio/proximity/srf04.c
Thomas Gleixner c942fddf87 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:37 -07:00

315 lines
7.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* SRF04: ultrasonic sensor for distance measuring by using GPIOs
*
* Copyright (c) 2017 Andreas Klinger <ak@it-klinger.de>
*
* For details about the device see:
* http://www.robot-electronics.co.uk/htm/srf04tech.htm
*
* the measurement cycle as timing diagram looks like:
*
* +---+
* GPIO | |
* trig: --+ +------------------------------------------------------
* ^ ^
* |<->|
* udelay(trigger_pulse_us)
*
* ultra +-+ +-+ +-+
* sonic | | | | | |
* burst: ---------+ +-+ +-+ +-----------------------------------------
* .
* ultra . +-+ +-+ +-+
* sonic . | | | | | |
* echo: ----------------------------------+ +-+ +-+ +----------------
* . .
* +------------------------+
* GPIO | |
* echo: -------------------+ +---------------
* ^ ^
* interrupt interrupt
* (ts_rising) (ts_falling)
* |<---------------------->|
* pulse time measured
* --> one round trip of ultra sonic waves
*/
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
struct srf04_cfg {
unsigned long trigger_pulse_us;
};
struct srf04_data {
struct device *dev;
struct gpio_desc *gpiod_trig;
struct gpio_desc *gpiod_echo;
struct mutex lock;
int irqnr;
ktime_t ts_rising;
ktime_t ts_falling;
struct completion rising;
struct completion falling;
const struct srf04_cfg *cfg;
};
static const struct srf04_cfg srf04_cfg = {
.trigger_pulse_us = 10,
};
static const struct srf04_cfg mb_lv_cfg = {
.trigger_pulse_us = 20,
};
static irqreturn_t srf04_handle_irq(int irq, void *dev_id)
{
struct iio_dev *indio_dev = dev_id;
struct srf04_data *data = iio_priv(indio_dev);
ktime_t now = ktime_get();
if (gpiod_get_value(data->gpiod_echo)) {
data->ts_rising = now;
complete(&data->rising);
} else {
data->ts_falling = now;
complete(&data->falling);
}
return IRQ_HANDLED;
}
static int srf04_read(struct srf04_data *data)
{
int ret;
ktime_t ktime_dt;
u64 dt_ns;
u32 time_ns, distance_mm;
/*
* just one read-echo-cycle can take place at a time
* ==> lock against concurrent reading calls
*/
mutex_lock(&data->lock);
reinit_completion(&data->rising);
reinit_completion(&data->falling);
gpiod_set_value(data->gpiod_trig, 1);
udelay(data->cfg->trigger_pulse_us);
gpiod_set_value(data->gpiod_trig, 0);
/* it cannot take more than 20 ms */
ret = wait_for_completion_killable_timeout(&data->rising, HZ/50);
if (ret < 0) {
mutex_unlock(&data->lock);
return ret;
} else if (ret == 0) {
mutex_unlock(&data->lock);
return -ETIMEDOUT;
}
ret = wait_for_completion_killable_timeout(&data->falling, HZ/50);
if (ret < 0) {
mutex_unlock(&data->lock);
return ret;
} else if (ret == 0) {
mutex_unlock(&data->lock);
return -ETIMEDOUT;
}
ktime_dt = ktime_sub(data->ts_falling, data->ts_rising);
mutex_unlock(&data->lock);
dt_ns = ktime_to_ns(ktime_dt);
/*
* measuring more than 3 meters is beyond the capabilities of
* the sensor
* ==> filter out invalid results for not measuring echos of
* another us sensor
*
* formula:
* distance 3 m
* time = ---------- = --------- = 9404389 ns
* speed 319 m/s
*
* using a minimum speed at -20 °C of 319 m/s
*/
if (dt_ns > 9404389)
return -EIO;
time_ns = dt_ns;
/*
* the speed as function of the temperature is approximately:
*
* speed = 331,5 + 0,6 * Temp
* with Temp in °C
* and speed in m/s
*
* use 343 m/s as ultrasonic speed at 20 °C here in absence of the
* temperature
*
* therefore:
* time 343
* distance = ------ * -----
* 10^6 2
* with time in ns
* and distance in mm (one way)
*
* because we limit to 3 meters the multiplication with 343 just
* fits into 32 bit
*/
distance_mm = time_ns * 343 / 2000000;
return distance_mm;
}
static int srf04_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long info)
{
struct srf04_data *data = iio_priv(indio_dev);
int ret;
if (channel->type != IIO_DISTANCE)
return -EINVAL;
switch (info) {
case IIO_CHAN_INFO_RAW:
ret = srf04_read(data);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
/*
* theoretical maximum resolution is 3 mm
* 1 LSB is 1 mm
*/
*val = 0;
*val2 = 1000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
static const struct iio_info srf04_iio_info = {
.read_raw = srf04_read_raw,
};
static const struct iio_chan_spec srf04_chan_spec[] = {
{
.type = IIO_DISTANCE,
.info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
},
};
static const struct of_device_id of_srf04_match[] = {
{ .compatible = "devantech,srf04", .data = &srf04_cfg},
{ .compatible = "maxbotix,mb1000", .data = &mb_lv_cfg},
{ .compatible = "maxbotix,mb1010", .data = &mb_lv_cfg},
{ .compatible = "maxbotix,mb1020", .data = &mb_lv_cfg},
{ .compatible = "maxbotix,mb1030", .data = &mb_lv_cfg},
{ .compatible = "maxbotix,mb1040", .data = &mb_lv_cfg},
{},
};
MODULE_DEVICE_TABLE(of, of_srf04_match);
static int srf04_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct srf04_data *data;
struct iio_dev *indio_dev;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(struct srf04_data));
if (!indio_dev) {
dev_err(dev, "failed to allocate IIO device\n");
return -ENOMEM;
}
data = iio_priv(indio_dev);
data->dev = dev;
data->cfg = of_match_device(of_srf04_match, dev)->data;
mutex_init(&data->lock);
init_completion(&data->rising);
init_completion(&data->falling);
data->gpiod_trig = devm_gpiod_get(dev, "trig", GPIOD_OUT_LOW);
if (IS_ERR(data->gpiod_trig)) {
dev_err(dev, "failed to get trig-gpios: err=%ld\n",
PTR_ERR(data->gpiod_trig));
return PTR_ERR(data->gpiod_trig);
}
data->gpiod_echo = devm_gpiod_get(dev, "echo", GPIOD_IN);
if (IS_ERR(data->gpiod_echo)) {
dev_err(dev, "failed to get echo-gpios: err=%ld\n",
PTR_ERR(data->gpiod_echo));
return PTR_ERR(data->gpiod_echo);
}
if (gpiod_cansleep(data->gpiod_echo)) {
dev_err(data->dev, "cansleep-GPIOs not supported\n");
return -ENODEV;
}
data->irqnr = gpiod_to_irq(data->gpiod_echo);
if (data->irqnr < 0) {
dev_err(data->dev, "gpiod_to_irq: %d\n", data->irqnr);
return data->irqnr;
}
ret = devm_request_irq(dev, data->irqnr, srf04_handle_irq,
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
pdev->name, indio_dev);
if (ret < 0) {
dev_err(data->dev, "request_irq: %d\n", ret);
return ret;
}
platform_set_drvdata(pdev, indio_dev);
indio_dev->name = "srf04";
indio_dev->dev.parent = &pdev->dev;
indio_dev->info = &srf04_iio_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = srf04_chan_spec;
indio_dev->num_channels = ARRAY_SIZE(srf04_chan_spec);
return devm_iio_device_register(dev, indio_dev);
}
static struct platform_driver srf04_driver = {
.probe = srf04_probe,
.driver = {
.name = "srf04-gpio",
.of_match_table = of_srf04_match,
},
};
module_platform_driver(srf04_driver);
MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
MODULE_DESCRIPTION("SRF04 ultrasonic sensor for distance measuring using GPIOs");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:srf04");