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linux/drivers/rtc/rtc-tps6586x.c
Laxman Dewangan dc59ed3865 rtc: add RTC driver for TPS6586x 
Add an RTC driver for TPS6586X chips by TI.  This driver supports:

- Setting and getting time and date.
- Setting and reading alarm time.
- Alarm and interrupt functionlity.

[akpm@linux-foundation.org: remove stray semicolons]
[akpm@linux-foundation.org: start epoch in 2009]
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Tested-by: Marc Dietrich <marvin24@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-04 16:11:48 -08:00

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/*
* rtc-tps6586x.c: RTC driver for TI PMIC TPS6586X
*
* Copyright (c) 2012, NVIDIA Corporation.
*
* Author: Laxman Dewangan <ldewangan@nvidia.com>
*
* 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 version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
* whether express or implied; 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., 59 Temple Place, Suite 330, Boston, MA
* 02111-1307, USA
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mfd/tps6586x.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#define RTC_CTRL 0xc0
#define POR_RESET_N BIT(7)
#define OSC_SRC_SEL BIT(6)
#define RTC_ENABLE BIT(5) /* enables alarm */
#define RTC_BUF_ENABLE BIT(4) /* 32 KHz buffer enable */
#define PRE_BYPASS BIT(3) /* 0=1KHz or 1=32KHz updates */
#define CL_SEL_MASK (BIT(2)|BIT(1))
#define CL_SEL_POS 1
#define RTC_ALARM1_HI 0xc1
#define RTC_COUNT4 0xc6
/* start a PMU RTC access by reading the register prior to the RTC_COUNT4 */
#define RTC_COUNT4_DUMMYREAD 0xc5
/*only 14-bits width in second*/
#define ALM1_VALID_RANGE_IN_SEC 0x3FFF
#define TPS6586X_RTC_CL_SEL_1_5PF 0x0
#define TPS6586X_RTC_CL_SEL_6_5PF 0x1
#define TPS6586X_RTC_CL_SEL_7_5PF 0x2
#define TPS6586X_RTC_CL_SEL_12_5PF 0x3
struct tps6586x_rtc {
struct device *dev;
struct rtc_device *rtc;
int irq;
bool irq_en;
unsigned long long epoch_start;
};
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[6];
int ret;
int i;
ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD, sizeof(buff), buff);
if (ret < 0) {
dev_err(dev, "read counter failed with err %d\n", ret);
return ret;
}
for (i = 1; 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 ret;
rtc_tm_to_time(tm, &seconds);
if (seconds < rtc->epoch_start) {
dev_err(dev, "requested time unsupported\n");
return -EINVAL;
}
seconds -= rtc->epoch_start;
ticks = (unsigned long long)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;
/* Disable RTC before changing time */
ret = tps6586x_clr_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
if (ret < 0) {
dev_err(dev, "failed to clear RTC_ENABLE\n");
return ret;
}
ret = tps6586x_writes(tps_dev, RTC_COUNT4, sizeof(buff), buff);
if (ret < 0) {
dev_err(dev, "failed to program new time\n");
return ret;
}
/* Enable RTC */
ret = tps6586x_set_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
if (ret < 0) {
dev_err(dev, "failed to set RTC_ENABLE\n");
return ret;
}
return 0;
}
static int tps6586x_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
if (enabled && !rtc->irq_en) {
enable_irq(rtc->irq);
rtc->irq_en = true;
} else if (!enabled && rtc->irq_en) {
disable_irq(rtc->irq);
rtc->irq_en = false;
}
return 0;
}
static int tps6586x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
struct device *tps_dev = to_tps6586x_dev(dev);
unsigned long seconds;
unsigned long ticks;
unsigned long rtc_current_time;
unsigned long long rticks = 0;
u8 buff[3];
u8 rbuff[6];
int ret;
int i;
rtc_tm_to_time(&alrm->time, &seconds);
if (alrm->enabled && (seconds < rtc->epoch_start)) {
dev_err(dev, "can't set alarm to requested time\n");
return -EINVAL;
}
ret = tps6586x_rtc_alarm_irq_enable(dev, alrm->enabled);
if (ret < 0) {
dev_err(dev, "can't set alarm irq, err %d\n", ret);
return ret;
}
seconds -= rtc->epoch_start;
ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD,
sizeof(rbuff), rbuff);
if (ret < 0) {
dev_err(dev, "read counter failed with err %d\n", ret);
return ret;
}
for (i = 1; i < sizeof(rbuff); i++) {
rticks <<= 8;
rticks |= rbuff[i];
}
rtc_current_time = rticks >> 10;
if ((seconds - rtc_current_time) > ALM1_VALID_RANGE_IN_SEC)
seconds = rtc_current_time - 1;
ticks = (unsigned long long)seconds << 10;
buff[0] = (ticks >> 16) & 0xff;
buff[1] = (ticks >> 8) & 0xff;
buff[2] = ticks & 0xff;
ret = tps6586x_writes(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
if (ret)
dev_err(dev, "programming alarm failed with err %d\n", ret);
return ret;
}
static int tps6586x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
struct device *tps_dev = to_tps6586x_dev(dev);
unsigned long ticks;
unsigned long seconds;
u8 buff[3];
int ret;
ret = tps6586x_reads(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
if (ret) {
dev_err(dev, "read RTC_ALARM1_HI failed with err %d\n", ret);
return ret;
}
ticks = (buff[0] << 16) | (buff[1] << 8) | buff[2];
seconds = ticks >> 10;
seconds += rtc->epoch_start;
rtc_time_to_tm(seconds, &alrm->time);
return 0;
}
static const struct rtc_class_ops tps6586x_rtc_ops = {
.read_time = tps6586x_rtc_read_time,
.set_time = tps6586x_rtc_set_time,
.set_alarm = tps6586x_rtc_set_alarm,
.read_alarm = tps6586x_rtc_read_alarm,
.alarm_irq_enable = tps6586x_rtc_alarm_irq_enable,
};
static irqreturn_t tps6586x_rtc_irq(int irq, void *data)
{
struct tps6586x_rtc *rtc = data;
rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static int tps6586x_rtc_probe(struct platform_device *pdev)
{
struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
struct tps6586x_rtc *rtc;
int ret;
rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
if (!rtc)
return -ENOMEM;
rtc->dev = &pdev->dev;
rtc->irq = platform_get_irq(pdev, 0);
/* Set epoch start as 00:00:00:01:01:2009 */
rtc->epoch_start = mktime(2009, 1, 1, 0, 0, 0);
/* 1 kHz tick mode, enable tick counting */
ret = tps6586x_update(tps_dev, RTC_CTRL,
RTC_ENABLE | OSC_SRC_SEL |
((TPS6586X_RTC_CL_SEL_1_5PF << CL_SEL_POS) & CL_SEL_MASK),
RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
if (ret < 0) {
dev_err(&pdev->dev, "unable to start counter\n");
return ret;
}
platform_set_drvdata(pdev, rtc);
rtc->rtc = rtc_device_register(dev_name(&pdev->dev), &pdev->dev,
&tps6586x_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc->rtc)) {
ret = PTR_ERR(rtc->rtc);
dev_err(&pdev->dev, "RTC device register: ret %d\n", ret);
goto fail_rtc_register;
}
ret = request_threaded_irq(rtc->irq, NULL, tps6586x_rtc_irq,
IRQF_ONESHOT | IRQF_EARLY_RESUME,
dev_name(&pdev->dev), rtc);
if (ret < 0) {
dev_err(&pdev->dev, "request IRQ(%d) failed with ret %d\n",
rtc->irq, ret);
goto fail_req_irq;
}
disable_irq(rtc->irq);
device_set_wakeup_capable(&pdev->dev, 1);
return 0;
fail_req_irq:
rtc_device_unregister(rtc->rtc);
fail_rtc_register:
tps6586x_update(tps_dev, RTC_CTRL, 0,
RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
return ret;
};
static int tps6586x_rtc_remove(struct platform_device *pdev)
{
struct tps6586x_rtc *rtc = platform_get_drvdata(pdev);
struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
tps6586x_update(tps_dev, RTC_CTRL, 0,
RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
rtc_device_unregister(rtc->rtc);
free_irq(rtc->irq, rtc);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int tps6586x_rtc_suspend(struct device *dev)
{
struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
enable_irq_wake(rtc->irq);
return 0;
}
static int tps6586x_rtc_resume(struct device *dev)
{
struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
disable_irq_wake(rtc->irq);
return 0;
}
#endif
static const struct dev_pm_ops tps6586x_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(tps6586x_rtc_suspend, tps6586x_rtc_resume)
};
static struct platform_driver tps6586x_rtc_driver = {
.driver = {
.name = "tps6586x-rtc",
.owner = THIS_MODULE,
.pm = &tps6586x_pm_ops,
},
.probe = tps6586x_rtc_probe,
.remove = tps6586x_rtc_remove,
};
module_platform_driver(tps6586x_rtc_driver);
MODULE_ALIAS("platform:rtc-tps6586x");
MODULE_DESCRIPTION("TI TPS6586x RTC driver");
MODULE_AUTHOR("Laxman dewangan <ldewangan@nvidia.com>");
MODULE_LICENSE("GPL v2");
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