| /* |
| * 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 than a full |
| * 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 <linux/iio/iio.h> |
| #include <linux/iio/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 const struct iio_trigger_ops iio_gpio_trigger_ops = { |
| .owner = THIS_MODULE, |
| }; |
| |
| 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_trigger_alloc("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->ops = &iio_gpio_trigger_ops; |
| 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_trigger_put(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_trigger_put(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, |
| }, |
| }; |
| |
| module_platform_driver(iio_gpio_trigger_driver); |
| |
| MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); |
| MODULE_DESCRIPTION("Example gpio trigger for the iio subsystem"); |
| MODULE_LICENSE("GPL v2"); |