GPIOs can be used to generate triggers for any IIO device. Introduce generic GPIO trigger driver. It offers some options to tune polarity (e.g. rising/falling edge), and label so trigger name may be customized. By default, gpio triggers will be named gpiotrigX, where X is gpio number as returned by desc_to_gpio() call. Rising edge is selected if polarity isn't set. Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx> --- drivers/iio/trigger/Kconfig | 9 +++ drivers/iio/trigger/Makefile | 1 + drivers/iio/trigger/iio-trig-gpio.c | 112 ++++++++++++++++++++++++++++++++++++ 3 files changed, 122 insertions(+) create mode 100644 drivers/iio/trigger/iio-trig-gpio.c diff --git a/drivers/iio/trigger/Kconfig b/drivers/iio/trigger/Kconfig index e4d4e63..54b6706 100644 --- a/drivers/iio/trigger/Kconfig +++ b/drivers/iio/trigger/Kconfig @@ -5,6 +5,15 @@ menu "Triggers - standalone" +config IIO_GPIO_TRIGGER + tristate "Generic GPIO trigger" + help + Provides support for a GPIO based IIO trigger, when trigger + source has been connected to a GPIO line. + + To compile this driver as a module, choose M here: the + module will be called iio-gpio-trigger. + config IIO_HRTIMER_TRIGGER tristate "High resolution timer trigger" depends on IIO_SW_TRIGGER diff --git a/drivers/iio/trigger/Makefile b/drivers/iio/trigger/Makefile index 5c4ecd3..a984668 100644 --- a/drivers/iio/trigger/Makefile +++ b/drivers/iio/trigger/Makefile @@ -4,6 +4,7 @@ # When adding new entries keep the list in alphabetical order +obj-$(CONFIG_IIO_GPIO_TRIGGER) += iio-trig-gpio.o obj-$(CONFIG_IIO_HRTIMER_TRIGGER) += iio-trig-hrtimer.o obj-$(CONFIG_IIO_INTERRUPT_TRIGGER) += iio-trig-interrupt.o obj-$(CONFIG_IIO_STM32_TIMER_TRIGGER) += stm32-timer-trigger.o diff --git a/drivers/iio/trigger/iio-trig-gpio.c b/drivers/iio/trigger/iio-trig-gpio.c new file mode 100644 index 0000000..4b48df0 --- /dev/null +++ b/drivers/iio/trigger/iio-trig-gpio.c @@ -0,0 +1,112 @@ +/* + * Industrial I/O - GPIO based trigger support + * + * Copyright (C) 2017, STMicroelectronics - All Rights Reserved + * Author: Fabrice Gasnier <fabrice.gasnier@xxxxxx>. + * + * License type: GPLv2 + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * 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. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/gpio/consumer.h> +#include <linux/iio/iio.h> +#include <linux/iio/trigger.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/platform_device.h> + +static const struct iio_trigger_ops iio_gpio_trigger_ops = { + .owner = THIS_MODULE, +}; + +static int iio_gpio_trigger_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct gpio_desc *gpio; + char name[16]; + const char *label = NULL; + struct iio_trigger *trig; + unsigned long irqflags = IRQF_SHARED; + int irq, ret; + + gpio = devm_gpiod_get(&pdev->dev, NULL, GPIOD_IN); + if (IS_ERR(gpio)) { + if (PTR_ERR(gpio) != -EPROBE_DEFER) + dev_err(&pdev->dev, "gpio get failed (%ld)\n", + PTR_ERR(gpio)); + return PTR_ERR(gpio); + } + + if (of_property_read_string(np, "label", &label)) + snprintf(name, sizeof(name), "gpiotrig%d", desc_to_gpio(gpio)); + + if (of_property_read_bool(np, "gpio-trigger-rising-edge")) + irqflags |= IRQF_TRIGGER_RISING; + + if (of_property_read_bool(np, "gpio-trigger-falling-edge")) + irqflags |= IRQF_TRIGGER_FALLING; + + /* Default to rising edge */ + if (!(irqflags & IRQF_TRIGGER_MASK)) + irqflags |= IRQF_TRIGGER_RISING; + + trig = devm_iio_trigger_alloc(&pdev->dev, "%s", label ? label : name); + if (!trig) + return -ENOMEM; + trig->dev.parent = &pdev->dev; + trig->dev.of_node = pdev->dev.of_node; + trig->ops = &iio_gpio_trigger_ops; + + irq = gpiod_to_irq(gpio); + if (irq < 0) { + dev_err(&pdev->dev, "gpio %d to irq failed (%d)\n", + desc_to_gpio(gpio), irq); + return irq; + } + + ret = devm_request_irq(&pdev->dev, irq, + iio_trigger_generic_data_rdy_poll, irqflags, + trig->name, trig); + if (ret) { + dev_err(&pdev->dev, "request IRQ %d failed\n", irq); + return ret; + } + + ret = devm_iio_trigger_register(&pdev->dev, trig); + if (ret) + return ret; + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id iio_gpio_trigger_of_match[] = { + { .compatible = "iio-gpio-trigger" }, + {}, +}; +MODULE_DEVICE_TABLE(of, iio_gpio_trigger_of_match); +#endif + +static struct platform_driver iio_gpio_trigger_driver = { + .probe = iio_gpio_trigger_probe, + .driver = { + .name = "iio-gpio-trigger", + .of_match_table = of_match_ptr(iio_gpio_trigger_of_match), + }, +}; +module_platform_driver(iio_gpio_trigger_driver); + +MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@xxxxxx>"); +MODULE_DESCRIPTION("GPIO trigger for iio subsystem"); +MODULE_LICENSE("GPL v2"); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
