diff options
Diffstat (limited to 'drivers/platform/x86/dell/dell-smo8800.c')
| -rw-r--r-- | drivers/platform/x86/dell/dell-smo8800.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/platform/x86/dell/dell-smo8800.c b/drivers/platform/x86/dell/dell-smo8800.c new file mode 100644 index 0000000000..f7ec17c568 --- /dev/null +++ b/drivers/platform/x86/dell/dell-smo8800.c @@ -0,0 +1,192 @@ +// 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@kernel.org> + * + * This is loosely based on lis3lv02d driver. + */ + +#define DRIVER_NAME "smo8800" + +#include <linux/fs.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/miscdevice.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/platform_device.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 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; + + byte_data = min_t(u32, 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_probe(struct platform_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; + } + + platform_set_drvdata(device, smo8800); + + err = platform_get_irq(device, 0); + if (err < 0) + goto error; + smo8800->irq = err; + + 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 void smo8800_remove(struct platform_device *device) +{ + struct smo8800_device *smo8800 = platform_get_drvdata(device); + + free_irq(smo8800->irq, smo8800); + misc_deregister(&smo8800->miscdev); + dev_dbg(&device->dev, "device /dev/freefall unregistered\n"); +} + +/* NOTE: Keep this list in sync with drivers/i2c/busses/i2c-i801.c */ +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 platform_driver smo8800_driver = { + .probe = smo8800_probe, + .remove_new = smo8800_remove, + .driver = { + .name = DRIVER_NAME, + .acpi_match_table = smo8800_ids, + }, +}; +module_platform_driver(smo8800_driver); + +MODULE_DESCRIPTION("Dell Latitude freefall driver (ACPI SMO88XX)"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Sonal Santan, Pali Rohár"); 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