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/*
* drivers/rtc/rtc-tps6586x.c
*
* RTC driver for TI TPS6586x
*
* Copyright (c) 2010, NVIDIA Corporation.
*
* 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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mfd/tps6586x.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#define TPS_EPOCH 2009
#define RTC_CTRL 0xc0
# define RTC_ENABLE (1 << 5) /* enables tick updates */
# define RTC_HIRES (1 << 4) /* 1Khz or 32Khz updates */
#define RTC_ALARM1_HI 0xc1
#define RTC_COUNT4 0xc6
struct tps6586x_rtc {
unsigned long epoch_start;
struct rtc_device *rtc;
};
static inline struct device *to_tps6586x_dev(struct device *dev)
{
return dev->parent;
}
static int tps6586x_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
struct device *tps_dev = to_tps6586x_dev(dev);
unsigned long long ticks = 0;
unsigned long seconds;
u8 buff[5];
int err;
int i;
err = tps6586x_reads(tps_dev, RTC_COUNT4, sizeof(buff), buff);
if (err < 0) {
dev_err(dev, "failed to read counter\n");
return err;
}
for (i = 0; i < sizeof(buff); i++) {
ticks <<= 8;
ticks |= buff[i];
}
seconds = ticks >> 10;
seconds += rtc->epoch_start;
rtc_time_to_tm(seconds, tm);
return rtc_valid_tm(tm);
}
static int tps6586x_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
struct device *tps_dev = to_tps6586x_dev(dev);
unsigned long long ticks;
unsigned long seconds;
u8 buff[5];
int err;
rtc_tm_to_time(tm, &seconds);
if (WARN_ON(seconds < rtc->epoch_start)) {
dev_err(dev, "requested time unsupported\n");
return -EINVAL;
}
seconds -= rtc->epoch_start;
ticks = seconds << 10;
buff[0] = (ticks >> 32) & 0xff;
buff[1] = (ticks >> 24) & 0xff;
buff[2] = (ticks >> 16) & 0xff;
buff[3] = (ticks >> 8) & 0xff;
buff[4] = ticks & 0xff;
dev_info(dev, "setting time to %lu seconds (%llu ticks)\n",
seconds, ticks);
err = tps6586x_clr_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
if (err < 0) {
dev_err(dev, "failed to clear RTC_ENABLE\n");
return err;
}
err = tps6586x_writes(tps_dev, RTC_COUNT4, sizeof(buff), buff);
if (err < 0) {
dev_err(dev, "failed to program new time\n");
return err;
}
err = tps6586x_set_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
if (err < 0) {
dev_err(dev, "failed to set RTC_ENABLE\n");
return err;
}
return 0;
}
static const struct rtc_class_ops tps6586x_rtc_ops = {
.read_time = tps6586x_rtc_read_time,
.set_time = tps6586x_rtc_set_time,
};
static int __devinit tps6586x_rtc_probe(struct platform_device *pdev)
{
struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
struct tps6586x_rtc *rtc;
int err;
rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
if (!rtc)
return -ENOMEM;
rtc->epoch_start = mktime(TPS_EPOCH, 1, 1, 0, 0, 0);
rtc->rtc = rtc_device_register("tps6586x-rtc", &pdev->dev,
&tps6586x_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc->rtc)) {
err = PTR_ERR(rtc->rtc);
goto fail;
}
/* disable high-res mode, enable tick counting */
err = tps6586x_update(tps_dev, RTC_CTRL,
(RTC_ENABLE | RTC_HIRES), RTC_ENABLE);
if (err < 0) {
dev_err(&pdev->dev, "unable to start counter\n");
goto fail;
}
dev_set_drvdata(&pdev->dev, rtc);
return 0;
fail:
if (!IS_ERR_OR_NULL(rtc->rtc))
rtc_device_unregister(rtc->rtc);
kfree(rtc);
return err;
}
static int __devexit tps6586x_rtc_remove(struct platform_device *pdev)
{
struct tps6586x_rtc *rtc = dev_get_drvdata(&pdev->dev);
rtc_device_unregister(rtc->rtc);
kfree(rtc);
return 0;
}
static struct platform_driver tps6586x_rtc_driver = {
.driver = {
.name = "tps6586x-rtc",
.owner = THIS_MODULE,
},
.probe = tps6586x_rtc_probe,
.remove = __devexit_p(tps6586x_rtc_remove),
};
static int __init tps6586x_rtc_init(void)
{
return platform_driver_register(&tps6586x_rtc_driver);
}
module_init(tps6586x_rtc_init);
static void __exit tps6586x_rtc_exit(void)
{
platform_driver_unregister(&tps6586x_rtc_driver);
}
module_exit(tps6586x_rtc_exit);
MODULE_DESCRIPTION("TI TPS6586x RTC driver");
MODULE_AUTHOR("NVIDIA Corporation");
MODULE_LICENSE("GPL");
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