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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* dell-smo8800.c - Dell Latitude ACPI SMO88XX freefall sensor driver
*
* Copyright (C) 2012 Sonal Santan <sonal.santan@gmail.com>
* Copyright (C) 2014 Pali Rohár <pali.rohar@gmail.com>
*
* This is loosely based on lis3lv02d driver.
*/
#define DRIVER_NAME "smo8800"
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/acpi.h>
#include <linux/interrupt.h>
#include <linux/miscdevice.h>
#include <linux/uaccess.h>
struct smo8800_device {
u32 irq; /* acpi device irq */
atomic_t counter; /* count after last read */
struct miscdevice miscdev; /* for /dev/freefall */
unsigned long misc_opened; /* whether the device is open */
wait_queue_head_t misc_wait; /* Wait queue for the misc dev */
struct device *dev; /* acpi device */
};
static irqreturn_t smo8800_interrupt_quick(int irq, void *data)
{
struct smo8800_device *smo8800 = data;
atomic_inc(&smo8800->counter);
wake_up_interruptible(&smo8800->misc_wait);
return IRQ_WAKE_THREAD;
}
static irqreturn_t smo8800_interrupt_thread(int irq, void *data)
{
struct smo8800_device *smo8800 = data;
dev_info(smo8800->dev, "detected free fall\n");
return IRQ_HANDLED;
}
static acpi_status smo8800_get_resource(struct acpi_resource *resource,
void *context)
{
struct acpi_resource_extended_irq *irq;
if (resource->type != ACPI_RESOURCE_TYPE_EXTENDED_IRQ)
return AE_OK;
irq = &resource->data.extended_irq;
if (!irq || !irq->interrupt_count)
return AE_OK;
*((u32 *)context) = irq->interrupts[0];
return AE_CTRL_TERMINATE;
}
static u32 smo8800_get_irq(struct acpi_device *device)
{
u32 irq = 0;
acpi_status status;
status = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
smo8800_get_resource, &irq);
if (ACPI_FAILURE(status)) {
dev_err(&device->dev, "acpi_walk_resources failed\n");
return 0;
}
return irq;
}
static ssize_t smo8800_misc_read(struct file *file, char __user *buf,
size_t count, loff_t *pos)
{
struct smo8800_device *smo8800 = container_of(file->private_data,
struct smo8800_device, miscdev);
u32 data = 0;
unsigned char byte_data;
ssize_t retval = 1;
if (count < 1)
return -EINVAL;
atomic_set(&smo8800->counter, 0);
retval = wait_event_interruptible(smo8800->misc_wait,
(data = atomic_xchg(&smo8800->counter, 0)));
if (retval)
return retval;
retval = 1;
if (data < 255)
byte_data = data;
else
byte_data = 255;
if (put_user(byte_data, buf))
retval = -EFAULT;
return retval;
}
static int smo8800_misc_open(struct inode *inode, struct file *file)
{
struct smo8800_device *smo8800 = container_of(file->private_data,
struct smo8800_device, miscdev);
if (test_and_set_bit(0, &smo8800->misc_opened))
return -EBUSY; /* already open */
atomic_set(&smo8800->counter, 0);
return 0;
}
static int smo8800_misc_release(struct inode *inode, struct file *file)
{
struct smo8800_device *smo8800 = container_of(file->private_data,
struct smo8800_device, miscdev);
clear_bit(0, &smo8800->misc_opened); /* release the device */
return 0;
}
static const struct file_operations smo8800_misc_fops = {
.owner = THIS_MODULE,
.read = smo8800_misc_read,
.open = smo8800_misc_open,
.release = smo8800_misc_release,
};
static int smo8800_add(struct acpi_device *device)
{
int err;
struct smo8800_device *smo8800;
smo8800 = devm_kzalloc(&device->dev, sizeof(*smo8800), GFP_KERNEL);
if (!smo8800) {
dev_err(&device->dev, "failed to allocate device data\n");
return -ENOMEM;
}
smo8800->dev = &device->dev;
smo8800->miscdev.minor = MISC_DYNAMIC_MINOR;
smo8800->miscdev.name = "freefall";
smo8800->miscdev.fops = &smo8800_misc_fops;
init_waitqueue_head(&smo8800->misc_wait);
err = misc_register(&smo8800->miscdev);
if (err) {
dev_err(&device->dev, "failed to register misc dev: %d\n", err);
return err;
}
device->driver_data = smo8800;
smo8800->irq = smo8800_get_irq(device);
if (!smo8800->irq) {
dev_err(&device->dev, "failed to obtain IRQ\n");
err = -EINVAL;
goto error;
}
err = request_threaded_irq(smo8800->irq, smo8800_interrupt_quick,
smo8800_interrupt_thread,
IRQF_TRIGGER_RISING | IRQF_ONESHOT,
DRIVER_NAME, smo8800);
if (err) {
dev_err(&device->dev,
"failed to request thread for IRQ %d: %d\n",
smo8800->irq, err);
goto error;
}
dev_dbg(&device->dev, "device /dev/freefall registered with IRQ %d\n",
smo8800->irq);
return 0;
error:
misc_deregister(&smo8800->miscdev);
return err;
}
static int smo8800_remove(struct acpi_device *device)
{
struct smo8800_device *smo8800 = device->driver_data;
free_irq(smo8800->irq, smo8800);
misc_deregister(&smo8800->miscdev);
dev_dbg(&device->dev, "device /dev/freefall unregistered\n");
return 0;
}
static const struct acpi_device_id smo8800_ids[] = {
{ "SMO8800", 0 },
{ "SMO8801", 0 },
{ "SMO8810", 0 },
{ "SMO8811", 0 },
{ "SMO8820", 0 },
{ "SMO8821", 0 },
{ "SMO8830", 0 },
{ "SMO8831", 0 },
{ "", 0 },
};
MODULE_DEVICE_TABLE(acpi, smo8800_ids);
static struct acpi_driver smo8800_driver = {
.name = DRIVER_NAME,
.class = "Latitude",
.ids = smo8800_ids,
.ops = {
.add = smo8800_add,
.remove = smo8800_remove,
},
.owner = THIS_MODULE,
};
module_acpi_driver(smo8800_driver);
MODULE_DESCRIPTION("Dell Latitude freefall driver (ACPI SMO88XX)");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sonal Santan, Pali Rohár");
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