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222 lines
5.7 KiB
222 lines
5.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (c) 2011 Jonathan Cameron |
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* |
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* Companion module to the iio simple dummy example driver. |
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* The purpose of this is to generate 'fake' event interrupts thus |
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* allowing that driver's code to be as close as possible to that of |
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* a normal driver talking to hardware. The approach used here |
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* is not intended to be general and just happens to work for this |
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* particular use case. |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/slab.h> |
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#include <linux/interrupt.h> |
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#include <linux/irq.h> |
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#include <linux/mutex.h> |
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#include <linux/module.h> |
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#include <linux/sysfs.h> |
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#include "iio_dummy_evgen.h" |
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#include <linux/iio/iio.h> |
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#include <linux/iio/sysfs.h> |
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#include <linux/irq_sim.h> |
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/* Fiddly bit of faking and irq without hardware */ |
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#define IIO_EVENTGEN_NO 10 |
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/** |
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* struct iio_dummy_eventgen - event generator specific state |
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* @regs: irq regs we are faking |
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* @lock: protect the evgen state |
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* @inuse: mask of which irqs are connected |
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* @irq_sim: interrupt simulator |
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* @base: base of irq range |
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* @irq_sim_domain: irq simulator domain |
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*/ |
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struct iio_dummy_eventgen { |
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struct iio_dummy_regs regs[IIO_EVENTGEN_NO]; |
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struct mutex lock; |
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bool inuse[IIO_EVENTGEN_NO]; |
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struct irq_domain *irq_sim_domain; |
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}; |
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/* We can only ever have one instance of this 'device' */ |
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static struct iio_dummy_eventgen *iio_evgen; |
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static int iio_dummy_evgen_create(void) |
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{ |
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int ret; |
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iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL); |
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if (!iio_evgen) |
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return -ENOMEM; |
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iio_evgen->irq_sim_domain = irq_domain_create_sim(NULL, |
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IIO_EVENTGEN_NO); |
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if (IS_ERR(iio_evgen->irq_sim_domain)) { |
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ret = PTR_ERR(iio_evgen->irq_sim_domain); |
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kfree(iio_evgen); |
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return ret; |
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} |
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mutex_init(&iio_evgen->lock); |
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return 0; |
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} |
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/** |
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* iio_dummy_evgen_get_irq() - get an evgen provided irq for a device |
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* |
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* This function will give a free allocated irq to a client device. |
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* That irq can then be caused to 'fire' by using the associated sysfs file. |
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*/ |
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int iio_dummy_evgen_get_irq(void) |
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{ |
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int i, ret = 0; |
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if (!iio_evgen) |
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return -ENODEV; |
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mutex_lock(&iio_evgen->lock); |
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for (i = 0; i < IIO_EVENTGEN_NO; i++) { |
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if (!iio_evgen->inuse[i]) { |
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ret = irq_create_mapping(iio_evgen->irq_sim_domain, i); |
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iio_evgen->inuse[i] = true; |
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break; |
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} |
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} |
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mutex_unlock(&iio_evgen->lock); |
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if (i == IIO_EVENTGEN_NO) |
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return -ENOMEM; |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_irq); |
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/** |
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* iio_dummy_evgen_release_irq() - give the irq back. |
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* @irq: irq being returned to the pool |
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* |
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* Used by client driver instances to give the irqs back when they disconnect |
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*/ |
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void iio_dummy_evgen_release_irq(int irq) |
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{ |
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struct irq_data *irqd = irq_get_irq_data(irq); |
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mutex_lock(&iio_evgen->lock); |
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iio_evgen->inuse[irqd_to_hwirq(irqd)] = false; |
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irq_dispose_mapping(irq); |
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mutex_unlock(&iio_evgen->lock); |
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} |
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EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq); |
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struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq) |
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{ |
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struct irq_data *irqd = irq_get_irq_data(irq); |
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return &iio_evgen->regs[irqd_to_hwirq(irqd)]; |
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} |
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EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs); |
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static void iio_dummy_evgen_free(void) |
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{ |
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irq_domain_remove_sim(iio_evgen->irq_sim_domain); |
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kfree(iio_evgen); |
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} |
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static void iio_evgen_release(struct device *dev) |
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{ |
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iio_dummy_evgen_free(); |
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} |
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static ssize_t iio_evgen_poke(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, |
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size_t len) |
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{ |
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struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); |
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unsigned long event; |
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int ret, irq; |
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ret = kstrtoul(buf, 10, &event); |
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if (ret) |
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return ret; |
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iio_evgen->regs[this_attr->address].reg_id = this_attr->address; |
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iio_evgen->regs[this_attr->address].reg_data = event; |
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irq = irq_find_mapping(iio_evgen->irq_sim_domain, this_attr->address); |
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ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true); |
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if (ret) |
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return ret; |
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return len; |
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} |
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static IIO_DEVICE_ATTR(poke_ev0, S_IWUSR, NULL, &iio_evgen_poke, 0); |
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static IIO_DEVICE_ATTR(poke_ev1, S_IWUSR, NULL, &iio_evgen_poke, 1); |
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static IIO_DEVICE_ATTR(poke_ev2, S_IWUSR, NULL, &iio_evgen_poke, 2); |
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static IIO_DEVICE_ATTR(poke_ev3, S_IWUSR, NULL, &iio_evgen_poke, 3); |
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static IIO_DEVICE_ATTR(poke_ev4, S_IWUSR, NULL, &iio_evgen_poke, 4); |
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static IIO_DEVICE_ATTR(poke_ev5, S_IWUSR, NULL, &iio_evgen_poke, 5); |
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static IIO_DEVICE_ATTR(poke_ev6, S_IWUSR, NULL, &iio_evgen_poke, 6); |
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static IIO_DEVICE_ATTR(poke_ev7, S_IWUSR, NULL, &iio_evgen_poke, 7); |
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static IIO_DEVICE_ATTR(poke_ev8, S_IWUSR, NULL, &iio_evgen_poke, 8); |
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static IIO_DEVICE_ATTR(poke_ev9, S_IWUSR, NULL, &iio_evgen_poke, 9); |
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static struct attribute *iio_evgen_attrs[] = { |
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&iio_dev_attr_poke_ev0.dev_attr.attr, |
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&iio_dev_attr_poke_ev1.dev_attr.attr, |
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&iio_dev_attr_poke_ev2.dev_attr.attr, |
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&iio_dev_attr_poke_ev3.dev_attr.attr, |
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&iio_dev_attr_poke_ev4.dev_attr.attr, |
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&iio_dev_attr_poke_ev5.dev_attr.attr, |
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&iio_dev_attr_poke_ev6.dev_attr.attr, |
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&iio_dev_attr_poke_ev7.dev_attr.attr, |
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&iio_dev_attr_poke_ev8.dev_attr.attr, |
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&iio_dev_attr_poke_ev9.dev_attr.attr, |
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NULL, |
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}; |
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static const struct attribute_group iio_evgen_group = { |
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.attrs = iio_evgen_attrs, |
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}; |
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static const struct attribute_group *iio_evgen_groups[] = { |
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&iio_evgen_group, |
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NULL |
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}; |
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static struct device iio_evgen_dev = { |
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.bus = &iio_bus_type, |
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.groups = iio_evgen_groups, |
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.release = &iio_evgen_release, |
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}; |
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static __init int iio_dummy_evgen_init(void) |
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{ |
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int ret = iio_dummy_evgen_create(); |
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if (ret < 0) |
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return ret; |
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device_initialize(&iio_evgen_dev); |
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dev_set_name(&iio_evgen_dev, "iio_evgen"); |
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ret = device_add(&iio_evgen_dev); |
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if (ret) |
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put_device(&iio_evgen_dev); |
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return ret; |
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} |
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module_init(iio_dummy_evgen_init); |
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static __exit void iio_dummy_evgen_exit(void) |
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{ |
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device_unregister(&iio_evgen_dev); |
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} |
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module_exit(iio_dummy_evgen_exit); |
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MODULE_AUTHOR("Jonathan Cameron <[email protected]>"); |
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MODULE_DESCRIPTION("IIO dummy driver"); |
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MODULE_LICENSE("GPL v2");
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