Jetpack/kernel/nvidia/drivers/nvpps/nvpps_main.c

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/*
* Copyright (c) 2018-2019, NVIDIA CORPORATION. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/cdev.h>
#include <linux/poll.h>
#include <linux/gpio.h>
#include <linux/list.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <asm/arch_timer.h>
#include <linux/platform/tegra/ptp-notifier.h>
#include <uapi/linux/nvpps_ioctl.h>
//#define NVPPS_MAP_EQOS_REGS
//#define NVPPS_ARM_COUNTER_PROFILING
//#define NVPPS_EQOS_REG_PROFILING
#define MAX_NVPPS_SOURCES 1
#define NVPPS_DEF_MODE NVPPS_MODE_GPIO
/* statics */
static struct class *s_nvpps_class;
static dev_t s_nvpps_devt;
static DEFINE_MUTEX(s_nvpps_lock);
static DEFINE_IDR(s_nvpps_idr);
/* platform device instance data */
struct nvpps_device_data {
struct platform_device *pdev;
struct cdev cdev;
struct device *dev;
unsigned int id;
unsigned int gpio_pin;
int irq;
bool irq_registered;
bool pps_event_id_valid;
unsigned int pps_event_id;
u64 tsc;
u64 phc;
u64 irq_latency;
u64 tsc_res_ns;
raw_spinlock_t lock;
u32 evt_mode;
u32 tsc_mode;
struct timer_list timer;
volatile bool timer_inited;
wait_queue_head_t pps_event_queue;
struct fasync_struct *pps_event_async_queue;
#ifdef NVPPS_MAP_EQOS_REGS
u64 eqos_base_addr;
#endif /*NVPPS_MAP_EQOS_REGS*/
};
/* file instance data */
struct nvpps_file_data {
struct nvpps_device_data *pdev_data;
unsigned int pps_event_id_rd;
};
#ifdef NVPPS_MAP_EQOS_REGS
#define EQOS_BASE_ADDR 0x2490000
#define BASE_ADDRESS pdev_data->eqos_base_addr
#define MAC_STNSR_TSSS_LPOS 0
#define MAC_STNSR_TSSS_HPOS 30
#define GET_VALUE(data, lbit, hbit) ((data >> lbit) & (~(~0<<(hbit-lbit+1))))
#define MAC_STNSR_OFFSET ((volatile u32 *)(BASE_ADDRESS + 0xb0c))
#define MAC_STNSR_RD(data) (data) = ioread32((void *)MAC_STNSR_OFFSET);
#define MAC_STSR_OFFSET ((volatile u32 *)(BASE_ADDRESS + 0xb08))
#define MAC_STSR_RD(data) (data) = ioread32((void *)MAC_STSR_OFFSET);
#endif /*NVPPS_MAP_EQOS_REGS*/
static inline u64 __arch_counter_get_cntvct(void)
{
u64 cval;
asm volatile("mrs %0, cntvct_el0" : "=r" (cval));
return cval;
}
#ifdef NVPPS_MAP_EQOS_REGS
static inline u64 get_systime(struct nvpps_device_data *pdev_data, u64 *tsc)
{
u64 ns1, ns2, ns;
u32 varmac_stnsr1, varmac_stnsr2;
u32 varmac_stsr;
/* read the PHC */
MAC_STNSR_RD(varmac_stnsr1);
MAC_STSR_RD(varmac_stsr);
/* read the TSC */
*tsc = __arch_counter_get_cntvct();
/* read the nsec part of the PHC one more time */
MAC_STNSR_RD(varmac_stnsr2);
ns1 = GET_VALUE(varmac_stnsr1, MAC_STNSR_TSSS_LPOS, MAC_STNSR_TSSS_HPOS);
ns2 = GET_VALUE(varmac_stnsr2, MAC_STNSR_TSSS_LPOS, MAC_STNSR_TSSS_HPOS);
/* if ns1 is greater than ns2, it means nsec counter rollover
* happened. In that case read the updated sec counter again
*/
if (ns1 > ns2) {
/* let's read the TSC again */
*tsc = __arch_counter_get_cntvct();
/* read the second portion of the PHC */
MAC_STSR_RD(varmac_stsr);
/* convert sec/high time value to nanosecond */
ns = ns2 + (varmac_stsr * 1000000000ull);
} else {
/* convert sec/high time value to nanosecond */
ns = ns1 + (varmac_stsr * 1000000000ull);
}
return ns;
}
#endif /*NVPPS_MAP_EQOS_REGS*/
/*
* Report the PPS event
*/
static void nvpps_get_ts(struct nvpps_device_data *pdev_data, bool in_isr)
{
u64 tsc;
u64 irq_tsc = 0;
u64 phc = 0;
u64 irq_latency = 0;
unsigned long flags;
/* get the gpio interrupt timestamp */
if (in_isr) {
irq_tsc = __arch_counter_get_cntvct();
} else {
irq_tsc = __arch_counter_get_cntvct();//0;
}
#ifdef NVPPS_MAP_EQOS_REGS
/* get the PTP timestamp */
if (pdev_data->eqos_base_addr) {
/* get both the phc and tsc */
phc = get_systime(pdev_data, &tsc);
} else {
#endif /*NVPPS_MAP_EQOS_REGS*/
/* get the phc from eqos driver */
get_ptp_hwtime(&phc);
/* get the current TSC time */
tsc = __arch_counter_get_cntvct();
#ifdef NVPPS_MAP_EQOS_REGS
}
#endif /*NVPPS_MAP_EQOS_REGS*/
#ifdef NVPPS_ARM_COUNTER_PROFILING
{
u64 tmp;
int i;
irq_tsc = __arch_counter_get_cntvct();
for (i = 0; i < 98; i++) {
tmp = __arch_counter_get_cntvct();
}
tsc = __arch_counter_get_cntvct();
}
#endif /*NVPPS_ARM_COUNTER_PROFILING*/
#ifdef NVPPS_EQOS_REG_PROFILING
{
u32 varmac_stnsr;
u32 varmac_stsr;
int i;
irq_tsc = __arch_counter_get_cntvct();
for (i = 0; i < 100; i++) {
MAC_STNSR_RD(varmac_stnsr);
MAC_STSR_RD(varmac_stsr)
}
tsc = __arch_counter_get_cntvct();
}
#endif /*NVPPS_EQOS_REG_PROFILING*/
/* get the interrupt latency */
if (irq_tsc) {
irq_latency = (tsc - irq_tsc) * pdev_data->tsc_res_ns;
}
raw_spin_lock_irqsave(&pdev_data->lock, flags);
pdev_data->pps_event_id_valid = true;
pdev_data->pps_event_id++;
pdev_data->tsc = irq_tsc ? irq_tsc : tsc;
/* adjust the ptp time for the interrupt latency */
#if defined (NVPPS_ARM_COUNTER_PROFILING) || defined (NVPPS_EQOS_REG_PROFILING)
pdev_data->phc = phc;
#else /* !NVPPS_ARM_COUNTER_PROFILING && !NVPPS_EQOS_REG_PROFILING */
pdev_data->phc = phc ? phc - irq_latency : phc;
#endif /* NVPPS_ARM_COUNTER_PROFILING || NVPPS_EQOS_REG_PROFILING */
pdev_data->irq_latency = irq_latency;
raw_spin_unlock_irqrestore(&pdev_data->lock, flags);
/*dev_info(pdev_data->dev, "evt(%d) tsc(%llu) phc(%llu)\n", pdev_data->pps_event_id, pdev_data->tsc, pdev_data->phc);*/
/* event notification */
wake_up_interruptible(&pdev_data->pps_event_queue);
kill_fasync(&pdev_data->pps_event_async_queue, SIGIO, POLL_IN);
}
static irqreturn_t nvpps_gpio_isr(int irq, void *data)
{
struct nvpps_device_data *pdev_data = (struct nvpps_device_data *)data;
/* get timestamps for this event */
nvpps_get_ts(pdev_data, true);
return IRQ_HANDLED;
}
static void nvpps_timer_callback(unsigned long data)
{
struct nvpps_device_data *pdev_data = (struct nvpps_device_data *)data;
/* get timestamps for this event */
nvpps_get_ts(pdev_data, false);
/* set the next expire time */
if (pdev_data->timer_inited) {
mod_timer(&pdev_data->timer, jiffies + msecs_to_jiffies(1000));
}
}
static int set_mode(struct nvpps_device_data *pdev_data, u32 mode)
{
int err = 0;
if (mode != pdev_data->evt_mode) {
switch (mode) {
case NVPPS_MODE_GPIO:
if (pdev_data->timer_inited) {
pdev_data->timer_inited = false;
del_timer_sync(&pdev_data->timer);
}
if (!pdev_data->irq_registered) {
/* register IRQ handler */
err = request_irq(pdev_data->irq, nvpps_gpio_isr,
IRQF_TRIGGER_RISING | IRQF_NO_THREAD, "nvpps_isr", pdev_data);
if (err) {
dev_err(pdev_data->dev, "failed to acquire IRQ %d\n", pdev_data->irq);
} else {
pdev_data->irq_registered = true;
dev_info(pdev_data->dev, "Registered IRQ %d for nvpps\n", pdev_data->irq);
}
}
break;
case NVPPS_MODE_TIMER:
if (pdev_data->irq_registered) {
/* unregister IRQ handler */
devm_free_irq(&pdev_data->pdev->dev, pdev_data->irq, pdev_data);
pdev_data->irq_registered = false;
}
if (!pdev_data->timer_inited) {
setup_timer(&pdev_data->timer, nvpps_timer_callback, (unsigned long)pdev_data);
pdev_data->timer_inited = true;
/* setup timer interval to 1000 msecs */
mod_timer(&pdev_data->timer, jiffies + msecs_to_jiffies(1000));
}
break;
default:
return -EINVAL;
}
}
return err;
}
/* Character device stuff */
static unsigned int nvpps_poll(struct file *file, poll_table *wait)
{
struct nvpps_file_data *pfile_data = (struct nvpps_file_data *)file->private_data;
struct nvpps_device_data *pdev_data = pfile_data->pdev_data;
poll_wait(file, &pdev_data->pps_event_queue, wait);
if (pdev_data->pps_event_id_valid &&
(pfile_data->pps_event_id_rd != pdev_data->pps_event_id)) {
return POLLIN | POLLRDNORM;
} else {
return 0;
}
}
static int nvpps_fasync(int fd, struct file *file, int on)
{
struct nvpps_file_data *pfile_data = (struct nvpps_file_data *)file->private_data;
struct nvpps_device_data *pdev_data = pfile_data->pdev_data;
return fasync_helper(fd, file, on, &pdev_data->pps_event_async_queue);
}
static long nvpps_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct nvpps_file_data *pfile_data = (struct nvpps_file_data *)file->private_data;
struct nvpps_device_data *pdev_data = pfile_data->pdev_data;
struct nvpps_params params;
void __user *uarg = (void __user *)arg;
int err;
switch (cmd) {
case NVPPS_GETVERSION: {
struct nvpps_version version;
dev_dbg(pdev_data->dev, "NVPPS_GETVERSION\n");
/* Get the current parameters */
version.version.major = NVPPS_VERSION_MAJOR;
version.version.minor = NVPPS_VERSION_MINOR;
version.api.major = NVPPS_API_MAJOR;
version.api.minor = NVPPS_API_MINOR;
err = copy_to_user(uarg, &version, sizeof(struct nvpps_version));
if (err) {
return -EFAULT;
}
break;
}
case NVPPS_GETPARAMS:
dev_dbg(pdev_data->dev, "NVPPS_GETPARAMS\n");
/* Get the current parameters */
params.evt_mode = pdev_data->evt_mode;
params.tsc_mode = pdev_data->tsc_mode;
err = copy_to_user(uarg, &params, sizeof(struct nvpps_params));
if (err) {
return -EFAULT;
}
break;
case NVPPS_SETPARAMS:
dev_dbg(pdev_data->dev, "NVPPS_SETPARAMS\n");
err = copy_from_user(&params, uarg, sizeof(struct nvpps_params));
if (err) {
return -EFAULT;
}
err = set_mode(pdev_data, params.evt_mode);
if (err) {
dev_dbg(pdev_data->dev, "switch_mode to %d failed err(%d)\n", params.evt_mode, err);
return err;
}
pdev_data->evt_mode = params.evt_mode;
pdev_data->tsc_mode = params.tsc_mode;
break;
case NVPPS_GETEVENT: {
struct nvpps_timeevent time_event;
unsigned long flags;
dev_dbg(pdev_data->dev, "NVPPS_GETEVENT\n");
/* Return the fetched timestamp */
raw_spin_lock_irqsave(&pdev_data->lock, flags);
pfile_data->pps_event_id_rd = pdev_data->pps_event_id;
time_event.evt_nb = pdev_data->pps_event_id;
time_event.tsc = pdev_data->tsc;
time_event.ptp = pdev_data->phc;
time_event.irq_latency = pdev_data->irq_latency;
raw_spin_unlock_irqrestore(&pdev_data->lock, flags);
if (NVPPS_TSC_NSEC == pdev_data->tsc_mode) {
time_event.tsc *= pdev_data->tsc_res_ns;
}
time_event.tsc_res_ns = pdev_data->tsc_res_ns;
time_event.evt_mode = pdev_data->evt_mode;
time_event.tsc_mode = pdev_data->tsc_mode;
err = copy_to_user(uarg, &time_event, sizeof(struct nvpps_timeevent));
if (err) {
return -EFAULT;
}
break;
}
default:
return -ENOTTY;
}
return 0;
}
static int nvpps_open(struct inode *inode, struct file *file)
{
struct nvpps_device_data *pdev_data = container_of(inode->i_cdev, struct nvpps_device_data, cdev);
struct nvpps_file_data *pfile_data;
pfile_data = kzalloc(sizeof(struct nvpps_file_data), GFP_KERNEL);
if (!pfile_data) {
dev_err(&pdev_data->pdev->dev, "nvpps_open kzalloc() failed\n");
return -ENOMEM;
}
pfile_data->pdev_data = pdev_data;
pfile_data->pps_event_id_rd = (unsigned int)-1;
file->private_data = pfile_data;
kobject_get(&pdev_data->dev->kobj);
return 0;
}
static int nvpps_close(struct inode *inode, struct file *file)
{
struct nvpps_device_data *pdev_data = container_of(inode->i_cdev, struct nvpps_device_data, cdev);
if (file->private_data) {
kfree(file->private_data);
}
kobject_put(&pdev_data->dev->kobj);
return 0;
}
static const struct file_operations nvpps_fops = {
.owner = THIS_MODULE,
.poll = nvpps_poll,
.fasync = nvpps_fasync,
.unlocked_ioctl = nvpps_ioctl,
.open = nvpps_open,
.release = nvpps_close,
};
static void nvpps_dev_release(struct device *dev)
{
struct nvpps_device_data *pdev_data = dev_get_drvdata(dev);
cdev_del(&pdev_data->cdev);
mutex_lock(&s_nvpps_lock);
idr_remove(&s_nvpps_idr, pdev_data->id);
mutex_unlock(&s_nvpps_lock);
kfree(dev);
kfree(pdev_data);
}
static int nvpps_probe(struct platform_device *pdev)
{
struct nvpps_device_data *pdev_data;
struct device_node *np = pdev->dev.of_node;
dev_t devt;
int err;
dev_info(&pdev->dev, "%s\n", __FUNCTION__);
if (!np) {
dev_err(&pdev->dev, "no valid device node, probe failed\n");
return -EINVAL;
}
pdev_data = kzalloc(sizeof(struct nvpps_device_data), GFP_KERNEL);
if (!pdev_data) {
return -ENOMEM;
}
err = of_get_gpio(np, 0);
if (err < 0) {
dev_err(&pdev->dev, "unable to get GPIO from device tree\n");
return err;
} else {
pdev_data->gpio_pin = (unsigned int)err;
dev_info(&pdev->dev, "gpio_pin(%d)\n", pdev_data->gpio_pin);
}
/* GPIO setup */
if (gpio_is_valid(pdev_data->gpio_pin)) {
err = devm_gpio_request(&pdev->dev, pdev_data->gpio_pin, "gpio_pps");
if (err) {
dev_err(&pdev->dev, "failed to request GPIO %u\n",
pdev_data->gpio_pin);
return err;
}
err = gpio_direction_input(pdev_data->gpio_pin);
if (err) {
dev_err(&pdev->dev, "failed to set pin direction\n");
return -EINVAL;
}
/* IRQ setup */
err = gpio_to_irq(pdev_data->gpio_pin);
if (err < 0) {
dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", err);
return -EINVAL;
}
pdev_data->irq = err;
dev_info(&pdev->dev, "gpio_to_irq(%d)\n", pdev_data->irq);
}
#ifdef NVPPS_MAP_EQOS_REGS
/* remap base address for eqos*/
pdev_data->eqos_base_addr = (u64)devm_ioremap_nocache(&pdev->dev,
EQOS_BASE_ADDR, 4096);
dev_info(&pdev->dev, "map EQOS to (%p)\n", (void *)pdev_data->eqos_base_addr);
#endif /*NVPPS_MAP_EQOS_REGS*/
init_waitqueue_head(&pdev_data->pps_event_queue);
raw_spin_lock_init(&pdev_data->lock);
pdev_data->pdev = pdev;
pdev_data->evt_mode = 0; /*NVPPS_MODE_GPIO*/
pdev_data->tsc_mode = NVPPS_TSC_NSEC;
#define _PICO_SECS (1000000000000ULL)
pdev_data->tsc_res_ns = (_PICO_SECS / (u64)arch_timer_get_cntfrq()) / 1000;
#undef _PICO_SECS
dev_info(&pdev->dev, "tsc_res_ns(%llu)\n", pdev_data->tsc_res_ns);
/* character device setup */
#ifndef NVPPS_NO_DT
s_nvpps_class = class_create(THIS_MODULE, "nvpps");
if (IS_ERR(s_nvpps_class)) {
dev_err(&pdev->dev, "failed to allocate class\n");
return PTR_ERR(s_nvpps_class);
}
err = alloc_chrdev_region(&s_nvpps_devt, 0, MAX_NVPPS_SOURCES, "nvpps");
if (err < 0) {
dev_err(&pdev->dev, "failed to allocate char device region\n");
class_destroy(s_nvpps_class);
return err;
}
#endif /* !NVPPS_NO_DT */
/* get an idr for the device */
mutex_lock(&s_nvpps_lock);
err = idr_alloc(&s_nvpps_idr, pdev_data, 0, MAX_NVPPS_SOURCES, GFP_KERNEL);
if (err < 0) {
if (err == -ENOSPC) {
dev_err(&pdev->dev, "nvpps: out of idr \n");
err = -EBUSY;
}
mutex_unlock(&s_nvpps_lock);
return err;
}
pdev_data->id = err;
mutex_unlock(&s_nvpps_lock);
/* associate the cdev with the file operations */
cdev_init(&pdev_data->cdev, &nvpps_fops);
/* build up the device number */
devt = MKDEV(MAJOR(s_nvpps_devt), pdev_data->id);
pdev_data->cdev.owner = THIS_MODULE;
/* create the device node */
pdev_data->dev = device_create(s_nvpps_class, NULL, devt, pdev_data, "nvpps%d", pdev_data->id);
if (IS_ERR(pdev_data->dev)) {
err = PTR_ERR(pdev_data->dev);
goto error_ret;
}
pdev_data->dev->release = nvpps_dev_release;
err = cdev_add(&pdev_data->cdev, devt, 1);
if (err) {
dev_err(&pdev->dev, "nvpps: failed to add char device %d:%d\n", MAJOR(s_nvpps_devt), pdev_data->id);
device_destroy(s_nvpps_class, pdev_data->dev->devt);
return err;
}
dev_info(&pdev->dev, "nvpps cdev(%d:%d)\n", MAJOR(s_nvpps_devt), pdev_data->id);
platform_set_drvdata(pdev, pdev_data);
/* setup PPS event hndler */
err = set_mode(pdev_data, NVPPS_DEF_MODE);
if (err) {
dev_err(&pdev->dev, "set_mode failed err = %d\n", err);
device_destroy(s_nvpps_class, pdev_data->dev->devt);
return err;
}
pdev_data->evt_mode = NVPPS_DEF_MODE;
return 0;
error_ret:
cdev_del(&pdev_data->cdev);
mutex_lock(&s_nvpps_lock);
idr_remove(&s_nvpps_idr, pdev_data->id);
mutex_unlock(&s_nvpps_lock);
return err;
}
static int nvpps_remove(struct platform_device *pdev)
{
struct nvpps_device_data *pdev_data = platform_get_drvdata(pdev);
printk("%s\n", __FUNCTION__);
if (pdev_data) {
if (pdev_data->irq_registered) {
/* unregister IRQ handler */
free_irq(pdev_data->irq, pdev_data);
pdev_data->irq_registered = false;
dev_info(&pdev->dev, "removed IRQ %d for nvpps\n", pdev_data->irq);
}
if (pdev_data->timer_inited) {
pdev_data->timer_inited = false;
del_timer_sync(&pdev_data->timer);
}
#ifdef NVPPS_MAP_EQOS_REGS
if (pdev_data->eqos_base_addr) {
devm_iounmap(&pdev->dev, (void *)pdev_data->eqos_base_addr);
dev_info(&pdev->dev, "unmap EQOS reg space %p for nvpps\n", (void *)pdev_data->eqos_base_addr);
}
#endif /*NVPPS_MAP_EQOS_REGS*/
device_destroy(s_nvpps_class, pdev_data->dev->devt);
}
#ifndef NVPPS_NO_DT
class_unregister(s_nvpps_class);
class_destroy(s_nvpps_class);
unregister_chrdev_region(s_nvpps_devt, MAX_NVPPS_SOURCES);
#endif /* !NVPPS_NO_DT */
return 0;
}
#ifdef CONFIG_PM
static int nvpps_suspend(struct platform_device *pdev, pm_message_t state)
{
/*struct nvpps_device_data *pdev_data = platform_get_drvdata(pdev);*/
return 0;
}
static int nvpps_resume(struct platform_device *pdev)
{
/*struct nvpps_device_data *pdev_data = platform_get_drvdata(pdev);*/
return 0;
}
#endif /*CONFIG_PM*/
#ifndef NVPPS_NO_DT
static const struct of_device_id nvpps_of_table[] = {
{ .compatible = "nvidia,tegra194-nvpps", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, nvpps_of_table);
#endif /*!NVPPS_NO_DT*/
static struct platform_driver nvpps_plat_driver = {
.driver = {
.name = KBUILD_MODNAME,
.owner = THIS_MODULE,
#ifndef NVPPS_NO_DT
.of_match_table = of_match_ptr(nvpps_of_table),
#endif /*!NVPPS_NO_DT*/
},
.probe = nvpps_probe,
.remove = nvpps_remove,
#ifdef CONFIG_PM
.suspend = nvpps_suspend,
.resume = nvpps_resume,
#endif /*CONFIG_PM*/
};
#ifdef NVPPS_NO_DT
/* module init
*/
static int __init nvpps_init(void)
{
int err;
printk("%s\n", __FUNCTION__);
s_nvpps_class = class_create(THIS_MODULE, "nvpps");
if (IS_ERR(s_nvpps_class)) {
printk("nvpps: failed to allocate class\n");
return PTR_ERR(s_nvpps_class);
}
err = alloc_chrdev_region(&s_nvpps_devt, 0, MAX_NVPPS_SOURCES, "nvpps");
if (err < 0) {
printk("nvpps: failed to allocate char device region\n");
class_destroy(s_nvpps_class);
return err;
}
printk("nvpps registered\n");
return platform_driver_register(&nvpps_plat_driver);
}
/* module fini
*/
static void __exit nvpps_exit(void)
{
printk("%s\n", __FUNCTION__);
platform_driver_unregister(&nvpps_plat_driver);
class_unregister(s_nvpps_class);
class_destroy(s_nvpps_class);
unregister_chrdev_region(s_nvpps_devt, MAX_NVPPS_SOURCES);
}
#endif /* NVPPS_NO_DT */
#ifdef NVPPS_NO_DT
module_init(nvpps_init);
module_exit(nvpps_exit);
#else /* !NVPPS_NO_DT */
module_platform_driver(nvpps_plat_driver);
#endif /* NVPPS_NO_DT */
MODULE_DESCRIPTION("NVidia Tegra PPS Driver");
MODULE_AUTHOR("David Tao tehyut@nvidia.com");
MODULE_LICENSE("GPL");