blob: 76e8807a04f3a9cc6c4c20e25d511a59ec24f4e2 [file] [log] [blame]
/* Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* 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/types.h>
#include <linux/msm_dsps.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/of_device.h>
#include <asm/arch_timer.h>
#include <linux/uaccess.h>
#define CLASS_NAME "ssc"
#define DRV_NAME "sensors"
#define DRV_VERSION "2.00"
struct sns_ssc_control_s {
struct class *dev_class;
dev_t dev_num;
struct device *dev;
struct cdev *cdev;
};
static struct sns_ssc_control_s sns_ctl;
/*
* Read QTimer clock ticks and scale down to 32KHz clock as used
* in DSPS
*/
static u32 sns_read_qtimer(void)
{
u64 val;
val = arch_counter_get_cntpct();
/*
* To convert ticks from 19.2 Mhz clock to 32768 Hz clock:
* x = (value * 32768) / 19200000
* This is same as first left shift the value by 4 bits, i.e. mutiply
* by 16, and then divide by 9375. The latter is preferable since
* QTimer tick (value) is 56-bit, so (value * 32768) could overflow,
* while (value * 16) will never do
*/
val <<= 4;
do_div(val, 9375);
return (u32)val;
}
static int sensors_ssc_open(struct inode *ip, struct file *fp)
{
return 0;
}
static int sensors_ssc_release(struct inode *inode, struct file *file)
{
return 0;
}
static long sensors_ssc_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
int ret = 0;
u32 val = 0;
switch (cmd) {
case DSPS_IOCTL_READ_SLOW_TIMER:
val = sns_read_qtimer();
ret = put_user(val, (u32 __user *) arg);
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
const struct file_operations sensors_ssc_fops = {
.owner = THIS_MODULE,
.open = sensors_ssc_open,
.release = sensors_ssc_release,
.unlocked_ioctl = sensors_ssc_ioctl
};
static int sensors_ssc_probe(struct platform_device *pdev)
{
int ret = 0;
sns_ctl.dev_class = class_create(THIS_MODULE, CLASS_NAME);
if (sns_ctl.dev_class == NULL) {
pr_err("%s: class_create fail.\n", __func__);
goto res_err;
}
ret = alloc_chrdev_region(&sns_ctl.dev_num, 0, 1, DRV_NAME);
if (ret) {
pr_err("%s: alloc_chrdev_region fail.\n", __func__);
goto alloc_chrdev_region_err;
}
sns_ctl.dev = device_create(sns_ctl.dev_class, NULL,
sns_ctl.dev_num,
&sns_ctl, DRV_NAME);
if (IS_ERR(sns_ctl.dev)) {
pr_err("%s: device_create fail.\n", __func__);
goto device_create_err;
}
sns_ctl.cdev = cdev_alloc();
if (sns_ctl.cdev == NULL) {
pr_err("%s: cdev_alloc fail.\n", __func__);
goto cdev_alloc_err;
}
cdev_init(sns_ctl.cdev, &sensors_ssc_fops);
sns_ctl.cdev->owner = THIS_MODULE;
ret = cdev_add(sns_ctl.cdev, sns_ctl.dev_num, 1);
if (ret) {
pr_err("%s: cdev_add fail.\n", __func__);
goto cdev_add_err;
}
return 0;
cdev_add_err:
kfree(sns_ctl.cdev);
cdev_alloc_err:
device_destroy(sns_ctl.dev_class, sns_ctl.dev_num);
device_create_err:
unregister_chrdev_region(sns_ctl.dev_num, 1);
alloc_chrdev_region_err:
class_destroy(sns_ctl.dev_class);
res_err:
return -ENODEV;
}
static int sensors_ssc_remove(struct platform_device *pdev)
{
cdev_del(sns_ctl.cdev);
kfree(sns_ctl.cdev);
sns_ctl.cdev = NULL;
device_destroy(sns_ctl.dev_class, sns_ctl.dev_num);
unregister_chrdev_region(sns_ctl.dev_num, 1);
class_destroy(sns_ctl.dev_class);
return 0;
}
static const struct of_device_id msm_ssc_sensors_dt_match[] = {
{.compatible = "qcom,msm-ssc-sensors"},
{},
};
MODULE_DEVICE_TABLE(of, msm_ssc_sensors_dt_match);
static struct platform_driver sensors_ssc_driver = {
.driver = {
.name = "sensors-ssc",
.owner = THIS_MODULE,
.of_match_table = msm_ssc_sensors_dt_match,
},
.probe = sensors_ssc_probe,
.remove = sensors_ssc_remove,
};
static int __init sensors_ssc_init(void)
{
int rc;
pr_debug("%s driver version %s.\n", DRV_NAME, DRV_VERSION);
rc = platform_driver_register(&sensors_ssc_driver);
if (rc) {
pr_err("%s: Failed to register sensors ssc driver\n",
__func__);
return rc;
}
return 0;
}
static void __exit sensors_ssc_exit(void)
{
platform_driver_unregister(&sensors_ssc_driver);
}
module_init(sensors_ssc_init);
module_exit(sensors_ssc_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Sensors SSC driver");