diff options
Diffstat (limited to 'drivers/platform/x86/dell-smo8800.c')
| -rw-r--r-- | drivers/platform/x86/dell-smo8800.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/drivers/platform/x86/dell-smo8800.c b/drivers/platform/x86/dell-smo8800.c new file mode 100644 index 000000000000..a653716055d1 --- /dev/null +++ b/drivers/platform/x86/dell-smo8800.c @@ -0,0 +1,233 @@ +/* + * dell-smo8800.c - Dell Latitude ACPI SMO8800/SMO8810 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> + +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 = 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; +} + +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 }, + { "SMO8810", 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 SMO8800/SMO8810)"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Sonal Santan, Pali Rohár"); 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