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linux/drivers/rtc/rtc-ab8500.c
Virupax Sadashivpetimath 0af62f4d1e rtc: AB8500 RTC driver 
Add a driver for the RTC on the AB8500 power management chip.  This is a
client of the AB8500 MFD driver.

Signed-off-by: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:41 -07:00

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/*
* Copyright (C) ST-Ericsson SA 2010
*
* License terms: GNU General Public License (GPL) version 2
* Author: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
*
* RTC clock driver for the RTC part of the AB8500 Power management chip.
* Based on RTC clock driver for the AB3100 Analog Baseband Chip by
* Linus Walleij <linus.walleij@stericsson.com>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/mfd/ab8500.h>
#include <linux/delay.h>
#define AB8500_RTC_SOFF_STAT_REG 0x0F00
#define AB8500_RTC_CC_CONF_REG 0x0F01
#define AB8500_RTC_READ_REQ_REG 0x0F02
#define AB8500_RTC_WATCH_TSECMID_REG 0x0F03
#define AB8500_RTC_WATCH_TSECHI_REG 0x0F04
#define AB8500_RTC_WATCH_TMIN_LOW_REG 0x0F05
#define AB8500_RTC_WATCH_TMIN_MID_REG 0x0F06
#define AB8500_RTC_WATCH_TMIN_HI_REG 0x0F07
#define AB8500_RTC_ALRM_MIN_LOW_REG 0x0F08
#define AB8500_RTC_ALRM_MIN_MID_REG 0x0F09
#define AB8500_RTC_ALRM_MIN_HI_REG 0x0F0A
#define AB8500_RTC_STAT_REG 0x0F0B
#define AB8500_RTC_BKUP_CHG_REG 0x0F0C
#define AB8500_RTC_FORCE_BKUP_REG 0x0F0D
#define AB8500_RTC_CALIB_REG 0x0F0E
#define AB8500_RTC_SWITCH_STAT_REG 0x0F0F
#define AB8500_REV_REG 0x1080
/* RtcReadRequest bits */
#define RTC_READ_REQUEST 0x01
#define RTC_WRITE_REQUEST 0x02
/* RtcCtrl bits */
#define RTC_ALARM_ENA 0x04
#define RTC_STATUS_DATA 0x01
#define COUNTS_PER_SEC (0xF000 / 60)
#define AB8500_RTC_EPOCH 2000
static const unsigned long ab8500_rtc_time_regs[] = {
AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG,
AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG,
AB8500_RTC_WATCH_TSECMID_REG
};
static const unsigned long ab8500_rtc_alarm_regs[] = {
AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG,
AB8500_RTC_ALRM_MIN_LOW_REG
};
/* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */
static unsigned long get_elapsed_seconds(int year)
{
unsigned long secs;
struct rtc_time tm = {
.tm_year = year - 1900,
.tm_mday = 1,
};
/*
* This function calculates secs from 1970 and not from
* 1900, even if we supply the offset from year 1900.
*/
rtc_tm_to_time(&tm, &secs);
return secs;
}
static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct ab8500 *ab8500 = dev_get_drvdata(dev->parent);
unsigned long timeout = jiffies + HZ;
int retval, i;
unsigned long mins, secs;
unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
/* Request a data read */
retval = ab8500_write(ab8500, AB8500_RTC_READ_REQ_REG,
RTC_READ_REQUEST);
if (retval < 0)
return retval;
/* Early AB8500 chips will not clear the rtc read request bit */
if (ab8500->revision == 0) {
msleep(1);
} else {
/* Wait for some cycles after enabling the rtc read in ab8500 */
while (time_before(jiffies, timeout)) {
retval = ab8500_read(ab8500, AB8500_RTC_READ_REQ_REG);
if (retval < 0)
return retval;
if (!(retval & RTC_READ_REQUEST))
break;
msleep(1);
}
}
/* Read the Watchtime registers */
for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
retval = ab8500_read(ab8500, ab8500_rtc_time_regs[i]);
if (retval < 0)
return retval;
buf[i] = retval;
}
mins = (buf[0] << 16) | (buf[1] << 8) | buf[2];
secs = (buf[3] << 8) | buf[4];
secs = secs / COUNTS_PER_SEC;
secs = secs + (mins * 60);
/* Add back the initially subtracted number of seconds */
secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
rtc_time_to_tm(secs, tm);
return rtc_valid_tm(tm);
}
static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct ab8500 *ab8500 = dev_get_drvdata(dev->parent);
int retval, i;
unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
unsigned long no_secs, no_mins, secs = 0;
if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) {
dev_dbg(dev, "year should be equal to or greater than %d\n",
AB8500_RTC_EPOCH);
return -EINVAL;
}
/* Get the number of seconds since 1970 */
rtc_tm_to_time(tm, &secs);
/*
* Convert it to the number of seconds since 01-01-2000 00:00:00, since
* we only have a small counter in the RTC.
*/
secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
no_mins = secs / 60;
no_secs = secs % 60;
/* Make the seconds count as per the RTC resolution */
no_secs = no_secs * COUNTS_PER_SEC;
buf[4] = no_secs & 0xFF;
buf[3] = (no_secs >> 8) & 0xFF;
buf[2] = no_mins & 0xFF;
buf[1] = (no_mins >> 8) & 0xFF;
buf[0] = (no_mins >> 16) & 0xFF;
for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
retval = ab8500_write(ab8500, ab8500_rtc_time_regs[i], buf[i]);
if (retval < 0)
return retval;
}
/* Request a data write */
return ab8500_write(ab8500, AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);
}
static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct ab8500 *ab8500 = dev_get_drvdata(dev->parent);
int retval, i;
int rtc_ctrl;
unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
unsigned long secs, mins;
/* Check if the alarm is enabled or not */
rtc_ctrl = ab8500_read(ab8500, AB8500_RTC_STAT_REG);
if (rtc_ctrl < 0)
return rtc_ctrl;
if (rtc_ctrl & RTC_ALARM_ENA)
alarm->enabled = 1;
else
alarm->enabled = 0;
alarm->pending = 0;
for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
retval = ab8500_read(ab8500, ab8500_rtc_alarm_regs[i]);
if (retval < 0)
return retval;
buf[i] = retval;
}
mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]);
secs = mins * 60;
/* Add back the initially subtracted number of seconds */
secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
rtc_time_to_tm(secs, &alarm->time);
return rtc_valid_tm(&alarm->time);
}
static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled)
{
struct ab8500 *ab8500 = dev_get_drvdata(dev->parent);
return ab8500_set_bits(ab8500, AB8500_RTC_STAT_REG, RTC_ALARM_ENA,
enabled ? RTC_ALARM_ENA : 0);
}
static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct ab8500 *ab8500 = dev_get_drvdata(dev->parent);
int retval, i;
unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
unsigned long mins, secs = 0;
if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) {
dev_dbg(dev, "year should be equal to or greater than %d\n",
AB8500_RTC_EPOCH);
return -EINVAL;
}
/* Get the number of seconds since 1970 */
rtc_tm_to_time(&alarm->time, &secs);
/*
* Convert it to the number of seconds since 01-01-2000 00:00:00, since
* we only have a small counter in the RTC.
*/
secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
mins = secs / 60;
buf[2] = mins & 0xFF;
buf[1] = (mins >> 8) & 0xFF;
buf[0] = (mins >> 16) & 0xFF;
/* Set the alarm time */
for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
retval = ab8500_write(ab8500, ab8500_rtc_alarm_regs[i], buf[i]);
if (retval < 0)
return retval;
}
return ab8500_rtc_irq_enable(dev, alarm->enabled);
}
static irqreturn_t rtc_alarm_handler(int irq, void *data)
{
struct rtc_device *rtc = data;
unsigned long events = RTC_IRQF | RTC_AF;
dev_dbg(&rtc->dev, "%s\n", __func__);
rtc_update_irq(rtc, 1, events);
return IRQ_HANDLED;
}
static const struct rtc_class_ops ab8500_rtc_ops = {
.read_time = ab8500_rtc_read_time,
.set_time = ab8500_rtc_set_time,
.read_alarm = ab8500_rtc_read_alarm,
.set_alarm = ab8500_rtc_set_alarm,
.alarm_irq_enable = ab8500_rtc_irq_enable,
};
static int __devinit ab8500_rtc_probe(struct platform_device *pdev)
{
struct ab8500 *ab8500 = dev_get_drvdata(pdev->dev.parent);
int err;
struct rtc_device *rtc;
int rtc_ctrl;
int irq;
irq = platform_get_irq_byname(pdev, "ALARM");
if (irq < 0)
return irq;
/* For RTC supply test */
err = ab8500_set_bits(ab8500, AB8500_RTC_STAT_REG, RTC_STATUS_DATA,
RTC_STATUS_DATA);
if (err < 0)
return err;
/* Wait for reset by the PorRtc */
msleep(1);
rtc_ctrl = ab8500_read(ab8500, AB8500_RTC_STAT_REG);
if (rtc_ctrl < 0)
return rtc_ctrl;
/* Check if the RTC Supply fails */
if (!(rtc_ctrl & RTC_STATUS_DATA)) {
dev_err(&pdev->dev, "RTC supply failure\n");
return -ENODEV;
}
rtc = rtc_device_register("ab8500-rtc", &pdev->dev, &ab8500_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtc)) {
dev_err(&pdev->dev, "Registration failed\n");
err = PTR_ERR(rtc);
return err;
}
err = request_threaded_irq(irq, NULL, rtc_alarm_handler, 0,
"ab8500-rtc", rtc);
if (err < 0) {
rtc_device_unregister(rtc);
return err;
}
platform_set_drvdata(pdev, rtc);
return 0;
}
static int __devexit ab8500_rtc_remove(struct platform_device *pdev)
{
struct rtc_device *rtc = platform_get_drvdata(pdev);
int irq = platform_get_irq_byname(pdev, "ALARM");
free_irq(irq, rtc);
rtc_device_unregister(rtc);
platform_set_drvdata(pdev, NULL);
return 0;
}
static struct platform_driver ab8500_rtc_driver = {
.driver = {
.name = "ab8500-rtc",
.owner = THIS_MODULE,
},
.probe = ab8500_rtc_probe,
.remove = __devexit_p(ab8500_rtc_remove),
};
static int __init ab8500_rtc_init(void)
{
return platform_driver_register(&ab8500_rtc_driver);
}
static void __exit ab8500_rtc_exit(void)
{
platform_driver_unregister(&ab8500_rtc_driver);
}
module_init(ab8500_rtc_init);
module_exit(ab8500_rtc_exit);
MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
MODULE_DESCRIPTION("AB8500 RTC Driver");
MODULE_LICENSE("GPL v2");
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