/drivers/staging/iio/trigger/iio-trig-gpio.c
https://bitbucket.org/slukk/jb-tsm-kernel-4.2 · C · 173 lines · 122 code · 26 blank · 25 comment · 11 complexity · 3319f2cd7dd50843a9b8a830c5f4dbf2 MD5 · raw file
- /*
- * Industrial I/O - gpio based trigger support
- *
- * Copyright (c) 2008 Jonathan Cameron
- *
- * 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.
- *
- * Currently this is more of a functioning proof of concept that a fully
- * fledged trigger driver.
- *
- * TODO:
- *
- * Add board config elements to allow specification of startup settings.
- */
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/platform_device.h>
- #include <linux/interrupt.h>
- #include <linux/gpio.h>
- #include <linux/slab.h>
- #include "../iio.h"
- #include "../trigger.h"
- static LIST_HEAD(iio_gpio_trigger_list);
- static DEFINE_MUTEX(iio_gpio_trigger_list_lock);
- struct iio_gpio_trigger_info {
- struct mutex in_use;
- unsigned int irq;
- };
- /*
- * Need to reference count these triggers and only enable gpio interrupts
- * as appropriate.
- */
- /* So what functionality do we want in here?... */
- /* set high / low as interrupt type? */
- static irqreturn_t iio_gpio_trigger_poll(int irq, void *private)
- {
- /* Timestamp not currently provided */
- iio_trigger_poll(private, 0);
- return IRQ_HANDLED;
- }
- static int iio_gpio_trigger_probe(struct platform_device *pdev)
- {
- struct iio_gpio_trigger_info *trig_info;
- struct iio_trigger *trig, *trig2;
- unsigned long irqflags;
- struct resource *irq_res;
- int irq, ret = 0, irq_res_cnt = 0;
- do {
- irq_res = platform_get_resource(pdev,
- IORESOURCE_IRQ, irq_res_cnt);
- if (irq_res == NULL) {
- if (irq_res_cnt == 0)
- dev_err(&pdev->dev, "No GPIO IRQs specified");
- break;
- }
- irqflags = (irq_res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
- for (irq = irq_res->start; irq <= irq_res->end; irq++) {
- trig = iio_allocate_trigger("irqtrig%d", irq);
- if (!trig) {
- ret = -ENOMEM;
- goto error_free_completed_registrations;
- }
- trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
- if (!trig_info) {
- ret = -ENOMEM;
- goto error_put_trigger;
- }
- trig->private_data = trig_info;
- trig_info->irq = irq;
- trig->owner = THIS_MODULE;
- ret = request_irq(irq, iio_gpio_trigger_poll,
- irqflags, trig->name, trig);
- if (ret) {
- dev_err(&pdev->dev,
- "request IRQ-%d failed", irq);
- goto error_free_trig_info;
- }
- ret = iio_trigger_register(trig);
- if (ret)
- goto error_release_irq;
- list_add_tail(&trig->alloc_list,
- &iio_gpio_trigger_list);
- }
- irq_res_cnt++;
- } while (irq_res != NULL);
- return 0;
- /* First clean up the partly allocated trigger */
- error_release_irq:
- free_irq(irq, trig);
- error_free_trig_info:
- kfree(trig_info);
- error_put_trigger:
- iio_put_trigger(trig);
- error_free_completed_registrations:
- /* The rest should have been added to the iio_gpio_trigger_list */
- list_for_each_entry_safe(trig,
- trig2,
- &iio_gpio_trigger_list,
- alloc_list) {
- trig_info = trig->private_data;
- free_irq(gpio_to_irq(trig_info->irq), trig);
- kfree(trig_info);
- iio_trigger_unregister(trig);
- }
- return ret;
- }
- static int iio_gpio_trigger_remove(struct platform_device *pdev)
- {
- struct iio_trigger *trig, *trig2;
- struct iio_gpio_trigger_info *trig_info;
- mutex_lock(&iio_gpio_trigger_list_lock);
- list_for_each_entry_safe(trig,
- trig2,
- &iio_gpio_trigger_list,
- alloc_list) {
- trig_info = trig->private_data;
- iio_trigger_unregister(trig);
- free_irq(trig_info->irq, trig);
- kfree(trig_info);
- iio_put_trigger(trig);
- }
- mutex_unlock(&iio_gpio_trigger_list_lock);
- return 0;
- }
- static struct platform_driver iio_gpio_trigger_driver = {
- .probe = iio_gpio_trigger_probe,
- .remove = iio_gpio_trigger_remove,
- .driver = {
- .name = "iio_gpio_trigger",
- .owner = THIS_MODULE,
- },
- };
- static int __init iio_gpio_trig_init(void)
- {
- return platform_driver_register(&iio_gpio_trigger_driver);
- }
- module_init(iio_gpio_trig_init);
- static void __exit iio_gpio_trig_exit(void)
- {
- platform_driver_unregister(&iio_gpio_trigger_driver);
- }
- module_exit(iio_gpio_trig_exit);
- MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
- MODULE_DESCRIPTION("Example gpio trigger for the iio subsystem");
- MODULE_LICENSE("GPL v2");