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linux/drivers/rtc/rtc-wm8350.c
Mark Brown 29c71b138c rtc: Suppress duplicate enable/disable of WM8350 update interrupt 
Unlike the wm8350-custom code genirq nests enable and disable calls
so we can't just unconditionally mask or unmask the interrupt,
we need to remember the state we set and only mask or unmask when
there is a real change.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: rtc-linux@googlegroups.com
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2010-03-07 22:16:56 +01:00

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/*
* Real Time Clock driver for Wolfson Microelectronics WM8350
*
* Copyright (C) 2007, 2008 Wolfson Microelectronics PLC.
*
* Author: Liam Girdwood
* linux@wolfsonmicro.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; either version 2 of the License, or (at your
* option) any later version.
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/interrupt.h>
#include <linux/ioctl.h>
#include <linux/completion.h>
#include <linux/mfd/wm8350/rtc.h>
#include <linux/mfd/wm8350/core.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#define WM8350_SET_ALM_RETRIES 5
#define WM8350_SET_TIME_RETRIES 5
#define WM8350_GET_TIME_RETRIES 5
#define to_wm8350_from_rtc_dev(d) container_of(d, struct wm8350, rtc.pdev.dev)
/*
* Read current time and date in RTC
*/
static int wm8350_rtc_readtime(struct device *dev, struct rtc_time *tm)
{
struct wm8350 *wm8350 = dev_get_drvdata(dev);
u16 time1[4], time2[4];
int retries = WM8350_GET_TIME_RETRIES, ret;
/*
* Read the time twice and compare.
* If time1 == time2, then time is valid else retry.
*/
do {
ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
4, time1);
if (ret < 0)
return ret;
ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
4, time2);
if (ret < 0)
return ret;
if (memcmp(time1, time2, sizeof(time1)) == 0) {
tm->tm_sec = time1[0] & WM8350_RTC_SECS_MASK;
tm->tm_min = (time1[0] & WM8350_RTC_MINS_MASK)
>> WM8350_RTC_MINS_SHIFT;
tm->tm_hour = time1[1] & WM8350_RTC_HRS_MASK;
tm->tm_wday = ((time1[1] >> WM8350_RTC_DAY_SHIFT)
& 0x7) - 1;
tm->tm_mon = ((time1[2] & WM8350_RTC_MTH_MASK)
>> WM8350_RTC_MTH_SHIFT) - 1;
tm->tm_mday = (time1[2] & WM8350_RTC_DATE_MASK);
tm->tm_year = ((time1[3] & WM8350_RTC_YHUNDREDS_MASK)
>> WM8350_RTC_YHUNDREDS_SHIFT) * 100;
tm->tm_year += time1[3] & WM8350_RTC_YUNITS_MASK;
tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon,
tm->tm_year);
tm->tm_year -= 1900;
dev_dbg(dev, "Read (%d left): %04x %04x %04x %04x\n",
retries,
time1[0], time1[1], time1[2], time1[3]);
return 0;
}
} while (retries--);
dev_err(dev, "timed out reading RTC time\n");
return -EIO;
}
/*
* Set current time and date in RTC
*/
static int wm8350_rtc_settime(struct device *dev, struct rtc_time *tm)
{
struct wm8350 *wm8350 = dev_get_drvdata(dev);
u16 time[4];
u16 rtc_ctrl;
int ret, retries = WM8350_SET_TIME_RETRIES;
time[0] = tm->tm_sec;
time[0] |= tm->tm_min << WM8350_RTC_MINS_SHIFT;
time[1] = tm->tm_hour;
time[1] |= (tm->tm_wday + 1) << WM8350_RTC_DAY_SHIFT;
time[2] = tm->tm_mday;
time[2] |= (tm->tm_mon + 1) << WM8350_RTC_MTH_SHIFT;
time[3] = ((tm->tm_year + 1900) / 100) << WM8350_RTC_YHUNDREDS_SHIFT;
time[3] |= (tm->tm_year + 1900) % 100;
dev_dbg(dev, "Setting: %04x %04x %04x %04x\n",
time[0], time[1], time[2], time[3]);
/* Set RTC_SET to stop the clock */
ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL, WM8350_RTC_SET);
if (ret < 0)
return ret;
/* Wait until confirmation of stopping */
do {
rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
schedule_timeout_uninterruptible(msecs_to_jiffies(1));
} while (--retries && !(rtc_ctrl & WM8350_RTC_STS));
if (!retries) {
dev_err(dev, "timed out on set confirmation\n");
return -EIO;
}
/* Write time to RTC */
ret = wm8350_block_write(wm8350, WM8350_RTC_SECONDS_MINUTES, 4, time);
if (ret < 0)
return ret;
/* Clear RTC_SET to start the clock */
ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
WM8350_RTC_SET);
return ret;
}
/*
* Read alarm time and date in RTC
*/
static int wm8350_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct wm8350 *wm8350 = dev_get_drvdata(dev);
struct rtc_time *tm = &alrm->time;
u16 time[4];
int ret;
ret = wm8350_block_read(wm8350, WM8350_ALARM_SECONDS_MINUTES, 4, time);
if (ret < 0)
return ret;
tm->tm_sec = time[0] & WM8350_RTC_ALMSECS_MASK;
if (tm->tm_sec == WM8350_RTC_ALMSECS_MASK)
tm->tm_sec = -1;
tm->tm_min = time[0] & WM8350_RTC_ALMMINS_MASK;
if (tm->tm_min == WM8350_RTC_ALMMINS_MASK)
tm->tm_min = -1;
else
tm->tm_min >>= WM8350_RTC_ALMMINS_SHIFT;
tm->tm_hour = time[1] & WM8350_RTC_ALMHRS_MASK;
if (tm->tm_hour == WM8350_RTC_ALMHRS_MASK)
tm->tm_hour = -1;
tm->tm_wday = ((time[1] >> WM8350_RTC_ALMDAY_SHIFT) & 0x7) - 1;
if (tm->tm_wday > 7)
tm->tm_wday = -1;
tm->tm_mon = time[2] & WM8350_RTC_ALMMTH_MASK;
if (tm->tm_mon == WM8350_RTC_ALMMTH_MASK)
tm->tm_mon = -1;
else
tm->tm_mon = (tm->tm_mon >> WM8350_RTC_ALMMTH_SHIFT) - 1;
tm->tm_mday = (time[2] & WM8350_RTC_ALMDATE_MASK);
if (tm->tm_mday == WM8350_RTC_ALMDATE_MASK)
tm->tm_mday = -1;
tm->tm_year = -1;
alrm->enabled = !(time[3] & WM8350_RTC_ALMSTS);
return 0;
}
static int wm8350_rtc_stop_alarm(struct wm8350 *wm8350)
{
int retries = WM8350_SET_ALM_RETRIES;
u16 rtc_ctrl;
int ret;
/* Set RTC_SET to stop the clock */
ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
WM8350_RTC_ALMSET);
if (ret < 0)
return ret;
/* Wait until confirmation of stopping */
do {
rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
schedule_timeout_uninterruptible(msecs_to_jiffies(1));
} while (retries-- && !(rtc_ctrl & WM8350_RTC_ALMSTS));
if (!(rtc_ctrl & WM8350_RTC_ALMSTS))
return -ETIMEDOUT;
return 0;
}
static int wm8350_rtc_start_alarm(struct wm8350 *wm8350)
{
int ret;
int retries = WM8350_SET_ALM_RETRIES;
u16 rtc_ctrl;
ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
WM8350_RTC_ALMSET);
if (ret < 0)
return ret;
/* Wait until confirmation */
do {
rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
schedule_timeout_uninterruptible(msecs_to_jiffies(1));
} while (retries-- && rtc_ctrl & WM8350_RTC_ALMSTS);
if (rtc_ctrl & WM8350_RTC_ALMSTS)
return -ETIMEDOUT;
return 0;
}
static int wm8350_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
struct wm8350 *wm8350 = dev_get_drvdata(dev);
if (enabled)
return wm8350_rtc_start_alarm(wm8350);
else
return wm8350_rtc_stop_alarm(wm8350);
}
static int wm8350_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct wm8350 *wm8350 = dev_get_drvdata(dev);
struct rtc_time *tm = &alrm->time;
u16 time[3];
int ret;
memset(time, 0, sizeof(time));
if (tm->tm_sec != -1)
time[0] |= tm->tm_sec;
else
time[0] |= WM8350_RTC_ALMSECS_MASK;
if (tm->tm_min != -1)
time[0] |= tm->tm_min << WM8350_RTC_ALMMINS_SHIFT;
else
time[0] |= WM8350_RTC_ALMMINS_MASK;
if (tm->tm_hour != -1)
time[1] |= tm->tm_hour;
else
time[1] |= WM8350_RTC_ALMHRS_MASK;
if (tm->tm_wday != -1)
time[1] |= (tm->tm_wday + 1) << WM8350_RTC_ALMDAY_SHIFT;
else
time[1] |= WM8350_RTC_ALMDAY_MASK;
if (tm->tm_mday != -1)
time[2] |= tm->tm_mday;
else
time[2] |= WM8350_RTC_ALMDATE_MASK;
if (tm->tm_mon != -1)
time[2] |= (tm->tm_mon + 1) << WM8350_RTC_ALMMTH_SHIFT;
else
time[2] |= WM8350_RTC_ALMMTH_MASK;
ret = wm8350_rtc_stop_alarm(wm8350);
if (ret < 0)
return ret;
/* Write time to RTC */
ret = wm8350_block_write(wm8350, WM8350_ALARM_SECONDS_MINUTES,
3, time);
if (ret < 0)
return ret;
if (alrm->enabled)
ret = wm8350_rtc_start_alarm(wm8350);
return ret;
}
static int wm8350_rtc_update_irq_enable(struct device *dev,
unsigned int enabled)
{
struct wm8350 *wm8350 = dev_get_drvdata(dev);
/* Suppress duplicate changes since genirq nests enable and
* disable calls. */
if (enabled == wm8350->rtc.update_enabled)
return 0;
if (enabled)
wm8350_unmask_irq(wm8350, WM8350_IRQ_RTC_SEC);
else
wm8350_mask_irq(wm8350, WM8350_IRQ_RTC_SEC);
wm8350->rtc.update_enabled = enabled;
return 0;
}
static irqreturn_t wm8350_rtc_alarm_handler(int irq, void *data)
{
struct wm8350 *wm8350 = data;
struct rtc_device *rtc = wm8350->rtc.rtc;
int ret;
rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
/* Make it one shot */
ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
WM8350_RTC_ALMSET);
if (ret != 0) {
dev_err(&(wm8350->rtc.pdev->dev),
"Failed to disable alarm: %d\n", ret);
}
return IRQ_HANDLED;
}
static irqreturn_t wm8350_rtc_update_handler(int irq, void *data)
{
struct wm8350 *wm8350 = data;
struct rtc_device *rtc = wm8350->rtc.rtc;
rtc_update_irq(rtc, 1, RTC_IRQF | RTC_UF);
return IRQ_HANDLED;
}
static const struct rtc_class_ops wm8350_rtc_ops = {
.read_time = wm8350_rtc_readtime,
.set_time = wm8350_rtc_settime,
.read_alarm = wm8350_rtc_readalarm,
.set_alarm = wm8350_rtc_setalarm,
.alarm_irq_enable = wm8350_rtc_alarm_irq_enable,
.update_irq_enable = wm8350_rtc_update_irq_enable,
};
#ifdef CONFIG_PM
static int wm8350_rtc_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct wm8350 *wm8350 = dev_get_drvdata(&pdev->dev);
int ret = 0;
u16 reg;
reg = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
if (device_may_wakeup(&wm8350->rtc.pdev->dev) &&
reg & WM8350_RTC_ALMSTS) {
ret = wm8350_rtc_stop_alarm(wm8350);
if (ret != 0)
dev_err(&pdev->dev, "Failed to stop RTC alarm: %d\n",
ret);
}
return ret;
}
static int wm8350_rtc_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct wm8350 *wm8350 = dev_get_drvdata(&pdev->dev);
int ret;
if (wm8350->rtc.alarm_enabled) {
ret = wm8350_rtc_start_alarm(wm8350);
if (ret != 0)
dev_err(&pdev->dev,
"Failed to restart RTC alarm: %d\n", ret);
}
return 0;
}
#else
#define wm8350_rtc_suspend NULL
#define wm8350_rtc_resume NULL
#endif
static int wm8350_rtc_probe(struct platform_device *pdev)
{
struct wm8350 *wm8350 = platform_get_drvdata(pdev);
struct wm8350_rtc *wm_rtc = &wm8350->rtc;
int ret = 0;
u16 timectl, power5;
timectl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
if (timectl & WM8350_RTC_BCD) {
dev_err(&pdev->dev, "RTC BCD mode not supported\n");
return -EINVAL;
}
if (timectl & WM8350_RTC_12HR) {
dev_err(&pdev->dev, "RTC 12 hour mode not supported\n");
return -EINVAL;
}
/* enable the RTC if it's not already enabled */
power5 = wm8350_reg_read(wm8350, WM8350_POWER_MGMT_5);
if (!(power5 & WM8350_RTC_TICK_ENA)) {
dev_info(wm8350->dev, "Starting RTC\n");
wm8350_reg_unlock(wm8350);
ret = wm8350_set_bits(wm8350, WM8350_POWER_MGMT_5,
WM8350_RTC_TICK_ENA);
if (ret < 0) {
dev_err(&pdev->dev, "failed to enable RTC: %d\n", ret);
return ret;
}
wm8350_reg_lock(wm8350);
}
if (timectl & WM8350_RTC_STS) {
int retries;
ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
WM8350_RTC_SET);
if (ret < 0) {
dev_err(&pdev->dev, "failed to start: %d\n", ret);
return ret;
}
retries = WM8350_SET_TIME_RETRIES;
do {
timectl = wm8350_reg_read(wm8350,
WM8350_RTC_TIME_CONTROL);
} while (timectl & WM8350_RTC_STS && --retries);
if (retries == 0) {
dev_err(&pdev->dev, "failed to start: timeout\n");
return -ENODEV;
}
}
device_init_wakeup(&pdev->dev, 1);
wm_rtc->rtc = rtc_device_register("wm8350", &pdev->dev,
&wm8350_rtc_ops, THIS_MODULE);
if (IS_ERR(wm_rtc->rtc)) {
ret = PTR_ERR(wm_rtc->rtc);
dev_err(&pdev->dev, "failed to register RTC: %d\n", ret);
return ret;
}
wm8350_register_irq(wm8350, WM8350_IRQ_RTC_SEC,
wm8350_rtc_update_handler, 0,
"RTC Seconds", wm8350);
wm8350_mask_irq(wm8350, WM8350_IRQ_RTC_SEC);
wm8350_register_irq(wm8350, WM8350_IRQ_RTC_ALM,
wm8350_rtc_alarm_handler, 0,
"RTC Alarm", wm8350);
return 0;
}
static int __devexit wm8350_rtc_remove(struct platform_device *pdev)
{
struct wm8350 *wm8350 = platform_get_drvdata(pdev);
struct wm8350_rtc *wm_rtc = &wm8350->rtc;
wm8350_free_irq(wm8350, WM8350_IRQ_RTC_SEC, wm8350);
wm8350_free_irq(wm8350, WM8350_IRQ_RTC_ALM, wm8350);
rtc_device_unregister(wm_rtc->rtc);
return 0;
}
static struct dev_pm_ops wm8350_rtc_pm_ops = {
.suspend = wm8350_rtc_suspend,
.resume = wm8350_rtc_resume,
};
static struct platform_driver wm8350_rtc_driver = {
.probe = wm8350_rtc_probe,
.remove = __devexit_p(wm8350_rtc_remove),
.driver = {
.name = "wm8350-rtc",
.pm = &wm8350_rtc_pm_ops,
},
};
static int __init wm8350_rtc_init(void)
{
return platform_driver_register(&wm8350_rtc_driver);
}
module_init(wm8350_rtc_init);
static void __exit wm8350_rtc_exit(void)
{
platform_driver_unregister(&wm8350_rtc_driver);
}
module_exit(wm8350_rtc_exit);
MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_DESCRIPTION("RTC driver for the WM8350");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm8350-rtc");
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