diff options
Diffstat (limited to 'drivers/iio/proximity/srf04.c')
| -rw-r--r-- | drivers/iio/proximity/srf04.c | 174 |
1 files changed, 136 insertions, 38 deletions
diff --git a/drivers/iio/proximity/srf04.c b/drivers/iio/proximity/srf04.c index 09c7b9c095b0..e97f9a20ac7a 100644 --- a/drivers/iio/proximity/srf04.c +++ b/drivers/iio/proximity/srf04.c @@ -1,20 +1,11 @@ +// 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> * - * 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. - * * For details about the device see: - * http://www.robot-electronics.co.uk/htm/srf04tech.htm + * https://www.robot-electronics.co.uk/htm/srf04tech.htm * * the measurement cycle as timing diagram looks like: * @@ -23,7 +14,7 @@ * trig: --+ +------------------------------------------------------ * ^ ^ * |<->| - * udelay(10) + * udelay(trigger_pulse_us) * * ultra +-+ +-+ +-+ * sonic | | | | | | @@ -46,26 +37,42 @@ #include <linux/err.h> #include <linux/gpio/consumer.h> #include <linux/kernel.h> +#include <linux/mod_devicetable.h> #include <linux/module.h> -#include <linux/of.h> #include <linux/platform_device.h> #include <linux/property.h> #include <linux/sched.h> #include <linux/interrupt.h> #include <linux/delay.h> +#include <linux/pm_runtime.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 gpio_desc *gpiod_power; struct mutex lock; int irqnr; ktime_t ts_rising; ktime_t ts_falling; struct completion rising; struct completion falling; + const struct srf04_cfg *cfg; + int startup_time_ms; +}; + +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) @@ -92,6 +99,11 @@ static int srf04_read(struct srf04_data *data) u64 dt_ns; u32 time_ns, distance_mm; + if (data->gpiod_power) { + ret = pm_runtime_resume_and_get(data->dev); + if (ret < 0) + return ret; + } /* * just one read-echo-cycle can take place at a time * ==> lock against concurrent reading calls @@ -102,10 +114,13 @@ static int srf04_read(struct srf04_data *data) reinit_completion(&data->falling); gpiod_set_value(data->gpiod_trig, 1); - udelay(10); + udelay(data->cfg->trigger_pulse_us); gpiod_set_value(data->gpiod_trig, 0); - /* it cannot take more than 20 ms */ + if (data->gpiod_power) + pm_runtime_put_autosuspend(data->dev); + + /* 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) { mutex_unlock(&data->lock); @@ -115,7 +130,8 @@ static int srf04_read(struct srf04_data *data) return -ETIMEDOUT; } - ret = wait_for_completion_killable_timeout(&data->falling, HZ/50); + /* it cannot take more than 50 ms until echo is falling */ + ret = wait_for_completion_killable_timeout(&data->falling, HZ/20); if (ret < 0) { mutex_unlock(&data->lock); return ret; @@ -130,19 +146,19 @@ static int srf04_read(struct srf04_data *data) dt_ns = ktime_to_ns(ktime_dt); /* - * measuring more than 3 meters is beyond the capabilities of - * the sensor + * measuring more than 6,45 meters is beyond the capabilities of + * the supported sensors * ==> filter out invalid results for not measuring echos of * another us sensor * * formula: - * distance 3 m - * time = ---------- = --------- = 9404389 ns - * speed 319 m/s + * distance 6,45 * 2 m + * time = ---------- = ------------ = 40438871 ns + * speed 319 m/s * * using a minimum speed at -20 °C of 319 m/s */ - if (dt_ns > 9404389) + if (dt_ns > 40438871) return -EIO; time_ns = dt_ns; @@ -154,20 +170,20 @@ static int srf04_read(struct srf04_data *data) * with Temp in °C * and speed in m/s * - * use 343 m/s as ultrasonic speed at 20 °C here in absence of the + * use 343,5 m/s as ultrasonic speed at 20 °C here in absence of the * temperature * * therefore: - * time 343 - * distance = ------ * ----- - * 10^6 2 + * time 343,5 time * 106 + * distance = ------ * ------- = ------------ + * 10^6 2 617176 * with time in ns * and distance in mm (one way) * - * because we limit to 3 meters the multiplication with 343 just + * because we limit to 6,45 meters the multiplication with 106 just * fits into 32 bit */ - distance_mm = time_ns * 343 / 2000000; + distance_mm = time_ns * 106 / 617176; return distance_mm; } @@ -215,6 +231,18 @@ static const struct iio_chan_spec srf04_chan_spec[] = { }, }; +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; @@ -223,13 +251,12 @@ static int srf04_probe(struct platform_device *pdev) 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"); + if (!indio_dev) return -ENOMEM; - } data = iio_priv(indio_dev); data->dev = dev; + data->cfg = device_get_match_data(dev); mutex_init(&data->lock); init_completion(&data->rising); @@ -249,6 +276,20 @@ static int srf04_probe(struct platform_device *pdev) return PTR_ERR(data->gpiod_echo); } + data->gpiod_power = devm_gpiod_get_optional(dev, "power", + GPIOD_OUT_LOW); + if (IS_ERR(data->gpiod_power)) { + dev_err(dev, "failed to get power-gpios: err=%ld\n", + PTR_ERR(data->gpiod_power)); + return PTR_ERR(data->gpiod_power); + } + if (data->gpiod_power) { + data->startup_time_ms = 100; + device_property_read_u32(dev, "startup-time-ms", &data->startup_time_ms); + dev_dbg(dev, "using power gpio: startup-time-ms=%d\n", + data->startup_time_ms); + } + if (gpiod_cansleep(data->gpiod_echo)) { dev_err(data->dev, "cansleep-GPIOs not supported\n"); return -ENODEV; @@ -271,27 +312,84 @@ static int srf04_probe(struct platform_device *pdev) 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); + ret = iio_device_register(indio_dev); + if (ret < 0) { + dev_err(data->dev, "iio_device_register: %d\n", ret); + return ret; + } + + if (data->gpiod_power) { + pm_runtime_set_autosuspend_delay(data->dev, 1000); + pm_runtime_use_autosuspend(data->dev); + + ret = pm_runtime_set_active(data->dev); + if (ret) { + dev_err(data->dev, "pm_runtime_set_active: %d\n", ret); + iio_device_unregister(indio_dev); + } + + pm_runtime_enable(data->dev); + pm_runtime_idle(data->dev); + } + + return ret; } -static const struct of_device_id of_srf04_match[] = { - { .compatible = "devantech,srf04", }, - {}, -}; +static void srf04_remove(struct platform_device *pdev) +{ + struct iio_dev *indio_dev = platform_get_drvdata(pdev); + struct srf04_data *data = iio_priv(indio_dev); -MODULE_DEVICE_TABLE(of, of_srf04_match); + iio_device_unregister(indio_dev); + + if (data->gpiod_power) { + pm_runtime_disable(data->dev); + pm_runtime_set_suspended(data->dev); + } +} + +static int srf04_pm_runtime_suspend(struct device *dev) +{ + struct platform_device *pdev = container_of(dev, + struct platform_device, dev); + struct iio_dev *indio_dev = platform_get_drvdata(pdev); + struct srf04_data *data = iio_priv(indio_dev); + + gpiod_set_value(data->gpiod_power, 0); + + return 0; +} + +static int srf04_pm_runtime_resume(struct device *dev) +{ + struct platform_device *pdev = container_of(dev, + struct platform_device, dev); + struct iio_dev *indio_dev = platform_get_drvdata(pdev); + struct srf04_data *data = iio_priv(indio_dev); + + gpiod_set_value(data->gpiod_power, 1); + msleep(data->startup_time_ms); + + return 0; +} + +static const struct dev_pm_ops srf04_pm_ops = { + RUNTIME_PM_OPS(srf04_pm_runtime_suspend, + srf04_pm_runtime_resume, NULL) +}; static struct platform_driver srf04_driver = { .probe = srf04_probe, + .remove = srf04_remove, .driver = { .name = "srf04-gpio", .of_match_table = of_srf04_match, + .pm = pm_ptr(&srf04_pm_ops), }, }; |