![Cristina Opriceana](/assets/img/avatar_default.png)
This patch moves the reference IIO dummy driver from drivers/staging/iio into a separate folder, drivers/iio/dummy and adds the proper Kconfig and Makefile for it. A new config menu entry called IIO dummy driver has also been added in the Industrial I/O support menu, corresponding to this driver. Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
263 lines
7.2 KiB
C
263 lines
7.2 KiB
C
/**
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* Copyright (c) 2011 Jonathan Cameron
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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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_work.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_handle_irq - helper struct to simulate interrupt generation
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* @work: irq_work used to run handlers from hardirq context
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* @irq: fake irq line number to trigger an interrupt
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*/
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struct iio_dummy_handle_irq {
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struct irq_work work;
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int irq;
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};
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/**
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* struct iio_dummy_evgen - evgen state
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* @chip: irq chip we are faking
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* @base: base of irq range
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* @enabled: mask of which irqs are enabled
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* @inuse: mask of which irqs are connected
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* @regs: irq regs we are faking
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* @lock: protect the evgen state
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* @handler: helper for a 'hardware-like' interrupt simulation
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*/
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struct iio_dummy_eventgen {
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struct irq_chip chip;
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int base;
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bool enabled[IIO_EVENTGEN_NO];
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bool inuse[IIO_EVENTGEN_NO];
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struct iio_dummy_regs regs[IIO_EVENTGEN_NO];
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struct mutex lock;
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struct iio_dummy_handle_irq handler;
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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 const char *iio_evgen_name = "iio_dummy_evgen";
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static void iio_dummy_event_irqmask(struct irq_data *d)
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{
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struct irq_chip *chip = irq_data_get_irq_chip(d);
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struct iio_dummy_eventgen *evgen =
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container_of(chip, struct iio_dummy_eventgen, chip);
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evgen->enabled[d->irq - evgen->base] = false;
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}
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static void iio_dummy_event_irqunmask(struct irq_data *d)
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{
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struct irq_chip *chip = irq_data_get_irq_chip(d);
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struct iio_dummy_eventgen *evgen =
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container_of(chip, struct iio_dummy_eventgen, chip);
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evgen->enabled[d->irq - evgen->base] = true;
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}
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static void iio_dummy_work_handler(struct irq_work *work)
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{
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struct iio_dummy_handle_irq *irq_handler;
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irq_handler = container_of(work, struct iio_dummy_handle_irq, work);
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handle_simple_irq(irq_to_desc(irq_handler->irq));
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}
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static int iio_dummy_evgen_create(void)
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{
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int ret, i;
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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->base = irq_alloc_descs(-1, 0, IIO_EVENTGEN_NO, 0);
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if (iio_evgen->base < 0) {
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ret = iio_evgen->base;
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kfree(iio_evgen);
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return ret;
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}
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iio_evgen->chip.name = iio_evgen_name;
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iio_evgen->chip.irq_mask = &iio_dummy_event_irqmask;
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iio_evgen->chip.irq_unmask = &iio_dummy_event_irqunmask;
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for (i = 0; i < IIO_EVENTGEN_NO; i++) {
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irq_set_chip(iio_evgen->base + i, &iio_evgen->chip);
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irq_set_handler(iio_evgen->base + i, &handle_simple_irq);
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irq_modify_status(iio_evgen->base + i,
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IRQ_NOREQUEST | IRQ_NOAUTOEN,
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IRQ_NOPROBE);
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}
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init_irq_work(&iio_evgen->handler.work, iio_dummy_work_handler);
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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 = iio_evgen->base + i;
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iio_evgen->inuse[i] = true;
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break;
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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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mutex_lock(&iio_evgen->lock);
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iio_evgen->inuse[irq - iio_evgen->base] = false;
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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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return &iio_evgen->regs[irq - iio_evgen->base];
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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_free_descs(iio_evgen->base, IIO_EVENTGEN_NO);
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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;
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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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iio_evgen->handler.irq = iio_evgen->base + this_attr->address;
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if (iio_evgen->enabled[this_attr->address])
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irq_work_queue(&iio_evgen->handler.work);
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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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return device_add(&iio_evgen_dev);
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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 <jic23@kernel.org>");
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MODULE_DESCRIPTION("IIO dummy driver");
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MODULE_LICENSE("GPL v2");
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