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SubjectRe: [PATCH v4 3/4] iio: ping: add parallax ping sensors
On Mon, 25 Nov 2019 09:05:02 +0100
Andreas Klinger <ak@it-klinger.de> wrote:

> Add support for parallax ping and laser ping sensors with just one pin
> for trigger and echo signal.
>
> This driver is based on srf04. In contrast to it it's necessary to
> change direction of the pin and to request the irq just for the period
> when the echo is rising and falling. Because this adds a lot of cases
> there is this individual driver for handling this type of sensors.
>
> Add a new configuration variable CONFIG_PING to Kconfig and Makefile.
>
> Signed-off-by: Andreas Klinger <ak@it-klinger.de>
> Reported-by: kbuild test robot <lkp@intel.com>
> Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Dropped v3 and applied v4. Added a note on 'what' was reported.

Thanks,

Jonathan

> ---
> drivers/iio/proximity/Kconfig | 15 ++
> drivers/iio/proximity/Makefile | 1 +
> drivers/iio/proximity/ping.c | 335 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 351 insertions(+)
> create mode 100644 drivers/iio/proximity/ping.c
>
> diff --git a/drivers/iio/proximity/Kconfig b/drivers/iio/proximity/Kconfig
> index d53601447da4..37606d400805 100644
> --- a/drivers/iio/proximity/Kconfig
> +++ b/drivers/iio/proximity/Kconfig
> @@ -58,6 +58,21 @@ config MB1232
> To compile this driver as a module, choose M here: the
> module will be called mb1232.
>
> +config PING
> + tristate "Parallax GPIO bitbanged ranger sensors"
> + depends on GPIOLIB
> + help
> + Say Y here to build a driver for GPIO bitbanged ranger sensors
> + with just one GPIO for the trigger and echo. This driver can be
> + used to measure the distance of objects.
> +
> + Actually supported are:
> + - Parallax PING))) (ultrasonic)
> + - Parallax LaserPING (time-of-flight)
> +
> + To compile this driver as a module, choose M here: the
> + module will be called ping.
> +
> config RFD77402
> tristate "RFD77402 ToF sensor"
> depends on I2C
> diff --git a/drivers/iio/proximity/Makefile b/drivers/iio/proximity/Makefile
> index 0bb5f9de13d6..c591b019304e 100644
> --- a/drivers/iio/proximity/Makefile
> +++ b/drivers/iio/proximity/Makefile
> @@ -8,6 +8,7 @@ obj-$(CONFIG_AS3935) += as3935.o
> obj-$(CONFIG_ISL29501) += isl29501.o
> obj-$(CONFIG_LIDAR_LITE_V2) += pulsedlight-lidar-lite-v2.o
> obj-$(CONFIG_MB1232) += mb1232.o
> +obj-$(CONFIG_PING) += ping.o
> obj-$(CONFIG_RFD77402) += rfd77402.o
> obj-$(CONFIG_SRF04) += srf04.o
> obj-$(CONFIG_SRF08) += srf08.o
> diff --git a/drivers/iio/proximity/ping.c b/drivers/iio/proximity/ping.c
> new file mode 100644
> index 000000000000..34aff108dff5
> --- /dev/null
> +++ b/drivers/iio/proximity/ping.c
> @@ -0,0 +1,335 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * PING: ultrasonic sensor for distance measuring by using only one GPIOs
> + *
> + * Copyright (c) 2019 Andreas Klinger <ak@it-klinger.de>
> + *
> + * For details about the devices see:
> + * http://parallax.com/sites/default/files/downloads/28041-LaserPING-2m-Rangefinder-Guide.pdf
> + * http://parallax.com/sites/default/files/downloads/28015-PING-Documentation-v1.6.pdf
> + *
> + * the measurement cycle as timing diagram looks like:
> + *
> + * GPIO ___ ________________________
> + * ping: __/ \____________/ \________________
> + * ^ ^ ^ ^
> + * |<->| interrupt interrupt
> + * udelay(5) (ts_rising) (ts_falling)
> + * |<---------------------->|
> + * . pulse time measured .
> + * . --> one round trip of ultra sonic waves
> + * ultra . .
> + * sonic _ _ _. .
> + * burst: _________/ \_/ \_/ \_________________________________________
> + * .
> + * ultra .
> + * sonic _ _ _.
> + * echo: __________________________________/ \_/ \_/ \________________
> + */
> +#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 ping_cfg {
> + unsigned long trigger_pulse_us; /* length of trigger pulse */
> + int laserping_error; /* support error code in */
> + /* pulse width of laser */
> + /* ping sensors */
> + s64 timeout_ns; /* timeout in ns */
> +};
> +
> +struct ping_data {
> + struct device *dev;
> + struct gpio_desc *gpiod_ping;
> + struct mutex lock;
> + int irqnr;
> + ktime_t ts_rising;
> + ktime_t ts_falling;
> + struct completion rising;
> + struct completion falling;
> + const struct ping_cfg *cfg;
> +};
> +
> +static const struct ping_cfg pa_ping_cfg = {
> + .trigger_pulse_us = 5,
> + .laserping_error = 0,
> + .timeout_ns = 18500000, /* 3 meters */
> +};
> +
> +static const struct ping_cfg pa_laser_ping_cfg = {
> + .trigger_pulse_us = 5,
> + .laserping_error = 1,
> + .timeout_ns = 15500000, /* 2 meters plus error codes */
> +};
> +
> +static irqreturn_t ping_handle_irq(int irq, void *dev_id)
> +{
> + struct iio_dev *indio_dev = dev_id;
> + struct ping_data *data = iio_priv(indio_dev);
> + ktime_t now = ktime_get();
> +
> + if (gpiod_get_value(data->gpiod_ping)) {
> + data->ts_rising = now;
> + complete(&data->rising);
> + } else {
> + data->ts_falling = now;
> + complete(&data->falling);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int ping_read(struct ping_data *data)
> +{
> + int ret;
> + ktime_t ktime_dt;
> + s64 dt_ns;
> + u32 time_ns, distance_mm;
> + struct platform_device *pdev = to_platform_device(data->dev);
> + struct iio_dev *indio_dev = iio_priv_to_dev(data);
> +
> + /*
> + * 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_ping, 1);
> + udelay(data->cfg->trigger_pulse_us);
> + gpiod_set_value(data->gpiod_ping, 0);
> +
> + ret = gpiod_direction_input(data->gpiod_ping);
> + if (ret < 0) {
> + mutex_unlock(&data->lock);
> + return ret;
> + }
> +
> + data->irqnr = gpiod_to_irq(data->gpiod_ping);
> + if (data->irqnr < 0) {
> + dev_err(data->dev, "gpiod_to_irq: %d\n", data->irqnr);
> + mutex_unlock(&data->lock);
> + return data->irqnr;
> + }
> +
> + ret = request_irq(data->irqnr, ping_handle_irq,
> + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
> + pdev->name, indio_dev);
> + if (ret < 0) {
> + dev_err(data->dev, "request_irq: %d\n", ret);
> + mutex_unlock(&data->lock);
> + return ret;
> + }
> +
> + /* it should not take more than 20 ms until echo is rising */
> + ret = wait_for_completion_killable_timeout(&data->rising, HZ/50);
> + if (ret < 0)
> + goto err_reset_direction;
> + else if (ret == 0) {
> + ret = -ETIMEDOUT;
> + goto err_reset_direction;
> + }
> +
> + /* it cannot take more than 50 ms until echo is falling */
> + ret = wait_for_completion_killable_timeout(&data->falling, HZ/20);
> + if (ret < 0)
> + goto err_reset_direction;
> + else if (ret == 0) {
> + ret = -ETIMEDOUT;
> + goto err_reset_direction;
> + }
> +
> + ktime_dt = ktime_sub(data->ts_falling, data->ts_rising);
> +
> + free_irq(data->irqnr, indio_dev);
> +
> + ret = gpiod_direction_output(data->gpiod_ping, GPIOD_OUT_LOW);
> + if (ret < 0) {
> + mutex_unlock(&data->lock);
> + return ret;
> + }
> +
> + mutex_unlock(&data->lock);
> +
> + dt_ns = ktime_to_ns(ktime_dt);
> + if (dt_ns > data->cfg->timeout_ns) {
> + dev_dbg(data->dev, "distance out of range: dt=%lldns\n",
> + dt_ns);
> + return -EIO;
> + }
> +
> + time_ns = dt_ns;
> +
> + /*
> + * read error code of laser ping sensor and give users chance to
> + * figure out error by using dynamic debuggging
> + */
> + if (data->cfg->laserping_error) {
> + if ((time_ns > 12500000) && (time_ns <= 13500000)) {
> + dev_dbg(data->dev, "target too close or to far\n");
> + return -EIO;
> + }
> + if ((time_ns > 13500000) && (time_ns <= 14500000)) {
> + dev_dbg(data->dev, "internal sensor error\n");
> + return -EIO;
> + }
> + if ((time_ns > 14500000) && (time_ns <= 15500000)) {
> + dev_dbg(data->dev, "internal sensor timeout\n");
> + return -EIO;
> + }
> + }
> +
> + /*
> + * 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 343,5 m/s as ultrasonic speed at 20 °C here in absence of the
> + * temperature
> + *
> + * therefore:
> + * time 343,5 time * 232
> + * distance = ------ * ------- = ------------
> + * 10^6 2 1350800
> + * with time in ns
> + * and distance in mm (one way)
> + *
> + * because we limit to 3 meters the multiplication with 232 just
> + * fits into 32 bit
> + */
> + distance_mm = time_ns * 232 / 1350800;
> +
> + return distance_mm;
> +
> +err_reset_direction:
> + free_irq(data->irqnr, indio_dev);
> + mutex_unlock(&data->lock);
> +
> + if (gpiod_direction_output(data->gpiod_ping, GPIOD_OUT_LOW))
> + dev_dbg(data->dev, "error in gpiod_direction_output\n");
> + return ret;
> +}
> +
> +static int ping_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *channel, int *val,
> + int *val2, long info)
> +{
> + struct ping_data *data = iio_priv(indio_dev);
> + int ret;
> +
> + if (channel->type != IIO_DISTANCE)
> + return -EINVAL;
> +
> + switch (info) {
> + case IIO_CHAN_INFO_RAW:
> + ret = ping_read(data);
> + if (ret < 0)
> + return ret;
> + *val = ret;
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + /*
> + * maximum resolution in datasheet is 1 mm
> + * 1 LSB is 1 mm
> + */
> + *val = 0;
> + *val2 = 1000;
> + return IIO_VAL_INT_PLUS_MICRO;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static const struct iio_info ping_iio_info = {
> + .read_raw = ping_read_raw,
> +};
> +
> +static const struct iio_chan_spec ping_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_ping_match[] = {
> + { .compatible = "parallax,ping", .data = &pa_ping_cfg},
> + { .compatible = "parallax,laserping", .data = &pa_ping_cfg},
> + {},
> +};
> +
> +MODULE_DEVICE_TABLE(of, of_ping_match);
> +
> +static int ping_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct ping_data *data;
> + struct iio_dev *indio_dev;
> +
> + indio_dev = devm_iio_device_alloc(dev, sizeof(struct ping_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_device_get_match_data(dev);
> +
> + mutex_init(&data->lock);
> + init_completion(&data->rising);
> + init_completion(&data->falling);
> +
> + data->gpiod_ping = devm_gpiod_get(dev, "ping", GPIOD_OUT_LOW);
> + if (IS_ERR(data->gpiod_ping)) {
> + dev_err(dev, "failed to get ping-gpios: err=%ld\n",
> + PTR_ERR(data->gpiod_ping));
> + return PTR_ERR(data->gpiod_ping);
> + }
> +
> + if (gpiod_cansleep(data->gpiod_ping)) {
> + dev_err(data->dev, "cansleep-GPIOs not supported\n");
> + return -ENODEV;
> + }
> +
> + platform_set_drvdata(pdev, indio_dev);
> +
> + indio_dev->name = "ping";
> + indio_dev->dev.parent = &pdev->dev;
> + indio_dev->info = &ping_iio_info;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->channels = ping_chan_spec;
> + indio_dev->num_channels = ARRAY_SIZE(ping_chan_spec);
> +
> + return devm_iio_device_register(dev, indio_dev);
> +}
> +
> +static struct platform_driver ping_driver = {
> + .probe = ping_probe,
> + .driver = {
> + .name = "ping-gpio",
> + .of_match_table = of_ping_match,
> + },
> +};
> +
> +module_platform_driver(ping_driver);
> +
> +MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
> +MODULE_DESCRIPTION("PING sensors for distance measuring using one GPIOs");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:ping");

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