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linux/drivers/rtc/rtc-ab8500.c

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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/abx500.h>
#include <linux/mfd/abx500/ab8500.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/pm_wakeirq.h>
#define AB8500_RTC_SOFF_STAT_REG 0x00
#define AB8500_RTC_CC_CONF_REG 0x01
#define AB8500_RTC_READ_REQ_REG 0x02
#define AB8500_RTC_WATCH_TSECMID_REG 0x03
#define AB8500_RTC_WATCH_TSECHI_REG 0x04
#define AB8500_RTC_WATCH_TMIN_LOW_REG 0x05
#define AB8500_RTC_WATCH_TMIN_MID_REG 0x06
#define AB8500_RTC_WATCH_TMIN_HI_REG 0x07
#define AB8500_RTC_ALRM_MIN_LOW_REG 0x08
#define AB8500_RTC_ALRM_MIN_MID_REG 0x09
#define AB8500_RTC_ALRM_MIN_HI_REG 0x0A
#define AB8500_RTC_STAT_REG 0x0B
#define AB8500_RTC_BKUP_CHG_REG 0x0C
#define AB8500_RTC_FORCE_BKUP_REG 0x0D
#define AB8500_RTC_CALIB_REG 0x0E
#define AB8500_RTC_SWITCH_STAT_REG 0x0F
/* 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 u8 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 u8 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)
{
unsigned long timeout = jiffies + HZ;
int retval, i;
unsigned long mins, secs;
unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
u8 value;
/* Request a data read */
retval = abx500_set_register_interruptible(dev,
AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST);
if (retval < 0)
return retval;
/* Wait for some cycles after enabling the rtc read in ab8500 */
while (time_before(jiffies, timeout)) {
retval = abx500_get_register_interruptible(dev,
AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value);
if (retval < 0)
return retval;
if (!(value & RTC_READ_REQUEST))
break;
usleep_range(1000, 5000);
}
/* Read the Watchtime registers */
for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
retval = abx500_get_register_interruptible(dev,
AB8500_RTC, ab8500_rtc_time_regs[i], &value);
if (retval < 0)
return retval;
buf[i] = value;
}
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 0;
}
static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
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 = abx500_set_register_interruptible(dev, AB8500_RTC,
ab8500_rtc_time_regs[i], buf[i]);
if (retval < 0)
return retval;
}
/* Request a data write */
return abx500_set_register_interruptible(dev, AB8500_RTC,
AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);
}
static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
int retval, i;
u8 rtc_ctrl, value;
unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
unsigned long secs, mins;
/* Check if the alarm is enabled or not */
retval = abx500_get_register_interruptible(dev, AB8500_RTC,
AB8500_RTC_STAT_REG, &rtc_ctrl);
if (retval < 0)
return retval;
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 = abx500_get_register_interruptible(dev, AB8500_RTC,
ab8500_rtc_alarm_regs[i], &value);
if (retval < 0)
return retval;
buf[i] = value;
}
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)
{
return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC,
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)
{
int retval, i;
unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
unsigned long mins, secs = 0, cursec = 0;
struct rtc_time curtm;
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);
/*
* Check whether alarm is set less than 1min.
* Since our RTC doesn't support alarm resolution less than 1min,
* return -EINVAL, so UIE EMUL can take it up, incase of UIE_ON
*/
ab8500_rtc_read_time(dev, &curtm); /* Read current time */
rtc_tm_to_time(&curtm, &cursec);
if ((secs - cursec) < 59) {
dev_dbg(dev, "Alarm less than 1 minute not supported\r\n");
return -EINVAL;
}
/*
* 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 = abx500_set_register_interruptible(dev, AB8500_RTC,
ab8500_rtc_alarm_regs[i], buf[i]);
if (retval < 0)
return retval;
}
return ab8500_rtc_irq_enable(dev, alarm->enabled);
}
static int ab8500_rtc_set_calibration(struct device *dev, int calibration)
{
int retval;
u8 rtccal = 0;
/*
* Check that the calibration value (which is in units of 0.5
* parts-per-million) is in the AB8500's range for RtcCalibration
* register. -128 (0x80) is not permitted because the AB8500 uses
* a sign-bit rather than two's complement, so 0x80 is just another
* representation of zero.
*/
if ((calibration < -127) || (calibration > 127)) {
dev_err(dev, "RtcCalibration value outside permitted range\n");
return -EINVAL;
}
/*
* The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
* so need to convert to this sort of representation before writing
* into RtcCalibration register...
*/
if (calibration >= 0)
rtccal = 0x7F & calibration;
else
rtccal = ~(calibration - 1) | 0x80;
retval = abx500_set_register_interruptible(dev, AB8500_RTC,
AB8500_RTC_CALIB_REG, rtccal);
return retval;
}
static int ab8500_rtc_get_calibration(struct device *dev, int *calibration)
{
int retval;
u8 rtccal = 0;
retval = abx500_get_register_interruptible(dev, AB8500_RTC,
AB8500_RTC_CALIB_REG, &rtccal);
if (retval >= 0) {
/*
* The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
* so need to convert value from RtcCalibration register into
* a two's complement signed value...
*/
if (rtccal & 0x80)
*calibration = 0 - (rtccal & 0x7F);
else
*calibration = 0x7F & rtccal;
}
return retval;
}
static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int retval;
int calibration = 0;
if (sscanf(buf, " %i ", &calibration) != 1) {
dev_err(dev, "Failed to store RTC calibration attribute\n");
return -EINVAL;
}
retval = ab8500_rtc_set_calibration(dev, calibration);
return retval ? retval : count;
}
static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev,
struct device_attribute *attr, char *buf)
{
int retval = 0;
int calibration = 0;
retval = ab8500_rtc_get_calibration(dev, &calibration);
if (retval < 0) {
dev_err(dev, "Failed to read RTC calibration attribute\n");
sprintf(buf, "0\n");
return retval;
}
return sprintf(buf, "%d\n", calibration);
}
static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR,
ab8500_sysfs_show_rtc_calibration,
ab8500_sysfs_store_rtc_calibration);
static int ab8500_sysfs_rtc_register(struct device *dev)
{
return device_create_file(dev, &dev_attr_rtc_calibration);
}
static void ab8500_sysfs_rtc_unregister(struct device *dev)
{
device_remove_file(dev, &dev_attr_rtc_calibration);
}
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 const struct platform_device_id ab85xx_rtc_ids[] = {
{ "ab8500-rtc", (kernel_ulong_t)&ab8500_rtc_ops, },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, ab85xx_rtc_ids);
static int ab8500_rtc_probe(struct platform_device *pdev)
{
const struct platform_device_id *platid = platform_get_device_id(pdev);
int err;
struct rtc_device *rtc;
u8 rtc_ctrl;
int irq;
irq = platform_get_irq_byname(pdev, "ALARM");
if (irq < 0)
return irq;
/* For RTC supply test */
err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC,
AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA);
if (err < 0)
return err;
/* Wait for reset by the PorRtc */
usleep_range(1000, 5000);
err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC,
AB8500_RTC_STAT_REG, &rtc_ctrl);
if (err < 0)
return err;
/* Check if the RTC Supply fails */
if (!(rtc_ctrl & RTC_STATUS_DATA)) {
dev_err(&pdev->dev, "RTC supply failure\n");
return -ENODEV;
}
device_init_wakeup(&pdev->dev, true);
rtc = devm_rtc_device_register(&pdev->dev, "ab8500-rtc",
(struct rtc_class_ops *)platid->driver_data,
THIS_MODULE);
if (IS_ERR(rtc)) {
dev_err(&pdev->dev, "Registration failed\n");
err = PTR_ERR(rtc);
return err;
}
err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
rtc_alarm_handler, IRQF_ONESHOT,
"ab8500-rtc", rtc);
if (err < 0)
return err;
dev_pm_set_wake_irq(&pdev->dev, irq);
platform_set_drvdata(pdev, rtc);
err = ab8500_sysfs_rtc_register(&pdev->dev);
if (err) {
dev_err(&pdev->dev, "sysfs RTC failed to register\n");
return err;
}
rtc->uie_unsupported = 1;
return 0;
}
static int ab8500_rtc_remove(struct platform_device *pdev)
{
dev_pm_clear_wake_irq(&pdev->dev);
device_init_wakeup(&pdev->dev, false);
ab8500_sysfs_rtc_unregister(&pdev->dev);
return 0;
}
static struct platform_driver ab8500_rtc_driver = {
.driver = {
.name = "ab8500-rtc",
},
.probe = ab8500_rtc_probe,
.remove = ab8500_rtc_remove,
.id_table = ab85xx_rtc_ids,
};
module_platform_driver(ab8500_rtc_driver);
MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
MODULE_DESCRIPTION("AB8500 RTC Driver");
MODULE_LICENSE("GPL v2");
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