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Release 4.11 drivers/platform/x86/dell-smo8800.c

/*
 *  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.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 */


#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; }

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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; }

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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; }

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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; }

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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 = 0; 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; byte_data = 1; retval = 1; if (data < 255) byte_data = data; else byte_data = 255; if (put_user(byte_data, buf)) retval = -EFAULT; return retval; }

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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; }

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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; }

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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; }

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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; }

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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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