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linux/drivers/rtc/rtc-vr41xx.c
Alexandre Belloni 0a53a16722 rtc: vr41xx: make alarms useful 
Currently, the IRQs are disabled when the rtc character device is closed.
This means that the device needs to stay open to get alarms while the usual
use case will open the device, set the alarm and close the device.

Keep the alarms functional on character device release. Note that the PIE
are never enabled and would anyway be disabled by the core.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2017-08-24 11:03:36 +02:00

365 lines
8.5 KiB
C
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/*
* Driver for NEC VR4100 series Real Time Clock unit.
*
* Copyright (C) 2003-2008 Yoichi Yuasa <yuasa@linux-mips.org>
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/log2.h>
#include <asm/div64.h>
MODULE_AUTHOR("Yoichi Yuasa <yuasa@linux-mips.org>");
MODULE_DESCRIPTION("NEC VR4100 series RTC driver");
MODULE_LICENSE("GPL v2");
/* RTC 1 registers */
#define ETIMELREG 0x00
#define ETIMEMREG 0x02
#define ETIMEHREG 0x04
/* RFU */
#define ECMPLREG 0x08
#define ECMPMREG 0x0a
#define ECMPHREG 0x0c
/* RFU */
#define RTCL1LREG 0x10
#define RTCL1HREG 0x12
#define RTCL1CNTLREG 0x14
#define RTCL1CNTHREG 0x16
#define RTCL2LREG 0x18
#define RTCL2HREG 0x1a
#define RTCL2CNTLREG 0x1c
#define RTCL2CNTHREG 0x1e
/* RTC 2 registers */
#define TCLKLREG 0x00
#define TCLKHREG 0x02
#define TCLKCNTLREG 0x04
#define TCLKCNTHREG 0x06
/* RFU */
#define RTCINTREG 0x1e
#define TCLOCK_INT 0x08
#define RTCLONG2_INT 0x04
#define RTCLONG1_INT 0x02
#define ELAPSEDTIME_INT 0x01
#define RTC_FREQUENCY 32768
#define MAX_PERIODIC_RATE 6553
static void __iomem *rtc1_base;
static void __iomem *rtc2_base;
#define rtc1_read(offset) readw(rtc1_base + (offset))
#define rtc1_write(offset, value) writew((value), rtc1_base + (offset))
#define rtc2_read(offset) readw(rtc2_base + (offset))
#define rtc2_write(offset, value) writew((value), rtc2_base + (offset))
static unsigned long epoch = 1970; /* Jan 1 1970 00:00:00 */
static DEFINE_SPINLOCK(rtc_lock);
static char rtc_name[] = "RTC";
static unsigned long periodic_count;
static unsigned int alarm_enabled;
static int aie_irq;
static int pie_irq;
static inline unsigned long read_elapsed_second(void)
{
unsigned long first_low, first_mid, first_high;
unsigned long second_low, second_mid, second_high;
do {
first_low = rtc1_read(ETIMELREG);
first_mid = rtc1_read(ETIMEMREG);
first_high = rtc1_read(ETIMEHREG);
second_low = rtc1_read(ETIMELREG);
second_mid = rtc1_read(ETIMEMREG);
second_high = rtc1_read(ETIMEHREG);
} while (first_low != second_low || first_mid != second_mid ||
first_high != second_high);
return (first_high << 17) | (first_mid << 1) | (first_low >> 15);
}
static inline void write_elapsed_second(unsigned long sec)
{
spin_lock_irq(&rtc_lock);
rtc1_write(ETIMELREG, (uint16_t)(sec << 15));
rtc1_write(ETIMEMREG, (uint16_t)(sec >> 1));
rtc1_write(ETIMEHREG, (uint16_t)(sec >> 17));
spin_unlock_irq(&rtc_lock);
}
static int vr41xx_rtc_read_time(struct device *dev, struct rtc_time *time)
{
unsigned long epoch_sec, elapsed_sec;
epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
elapsed_sec = read_elapsed_second();
rtc_time_to_tm(epoch_sec + elapsed_sec, time);
return 0;
}
static int vr41xx_rtc_set_time(struct device *dev, struct rtc_time *time)
{
unsigned long epoch_sec, current_sec;
epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
current_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
time->tm_hour, time->tm_min, time->tm_sec);
write_elapsed_second(current_sec - epoch_sec);
return 0;
}
static int vr41xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
{
unsigned long low, mid, high;
struct rtc_time *time = &wkalrm->time;
spin_lock_irq(&rtc_lock);
low = rtc1_read(ECMPLREG);
mid = rtc1_read(ECMPMREG);
high = rtc1_read(ECMPHREG);
wkalrm->enabled = alarm_enabled;
spin_unlock_irq(&rtc_lock);
rtc_time_to_tm((high << 17) | (mid << 1) | (low >> 15), time);
return 0;
}
static int vr41xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
{
unsigned long alarm_sec;
struct rtc_time *time = &wkalrm->time;
alarm_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
time->tm_hour, time->tm_min, time->tm_sec);
spin_lock_irq(&rtc_lock);
if (alarm_enabled)
disable_irq(aie_irq);
rtc1_write(ECMPLREG, (uint16_t)(alarm_sec << 15));
rtc1_write(ECMPMREG, (uint16_t)(alarm_sec >> 1));
rtc1_write(ECMPHREG, (uint16_t)(alarm_sec >> 17));
if (wkalrm->enabled)
enable_irq(aie_irq);
alarm_enabled = wkalrm->enabled;
spin_unlock_irq(&rtc_lock);
return 0;
}
static int vr41xx_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case RTC_EPOCH_READ:
return put_user(epoch, (unsigned long __user *)arg);
case RTC_EPOCH_SET:
/* Doesn't support before 1900 */
if (arg < 1900)
return -EINVAL;
epoch = arg;
break;
default:
return -ENOIOCTLCMD;
}
return 0;
}
static int vr41xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
spin_lock_irq(&rtc_lock);
if (enabled) {
if (!alarm_enabled) {
enable_irq(aie_irq);
alarm_enabled = 1;
}
} else {
if (alarm_enabled) {
disable_irq(aie_irq);
alarm_enabled = 0;
}
}
spin_unlock_irq(&rtc_lock);
return 0;
}
static irqreturn_t elapsedtime_interrupt(int irq, void *dev_id)
{
struct platform_device *pdev = (struct platform_device *)dev_id;
struct rtc_device *rtc = platform_get_drvdata(pdev);
rtc2_write(RTCINTREG, ELAPSEDTIME_INT);
rtc_update_irq(rtc, 1, RTC_AF);
return IRQ_HANDLED;
}
static irqreturn_t rtclong1_interrupt(int irq, void *dev_id)
{
struct platform_device *pdev = (struct platform_device *)dev_id;
struct rtc_device *rtc = platform_get_drvdata(pdev);
unsigned long count = periodic_count;
rtc2_write(RTCINTREG, RTCLONG1_INT);
rtc1_write(RTCL1LREG, count);
rtc1_write(RTCL1HREG, count >> 16);
rtc_update_irq(rtc, 1, RTC_PF);
return IRQ_HANDLED;
}
static const struct rtc_class_ops vr41xx_rtc_ops = {
.ioctl = vr41xx_rtc_ioctl,
.read_time = vr41xx_rtc_read_time,
.set_time = vr41xx_rtc_set_time,
.read_alarm = vr41xx_rtc_read_alarm,
.set_alarm = vr41xx_rtc_set_alarm,
.alarm_irq_enable = vr41xx_rtc_alarm_irq_enable,
};
static int rtc_probe(struct platform_device *pdev)
{
struct resource *res;
struct rtc_device *rtc;
int retval;
if (pdev->num_resources != 4)
return -EBUSY;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -EBUSY;
rtc1_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
if (!rtc1_base)
return -EBUSY;
res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
if (!res) {
retval = -EBUSY;
goto err_rtc1_iounmap;
}
rtc2_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
if (!rtc2_base) {
retval = -EBUSY;
goto err_rtc1_iounmap;
}
rtc = devm_rtc_device_register(&pdev->dev, rtc_name, &vr41xx_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtc)) {
retval = PTR_ERR(rtc);
goto err_iounmap_all;
}
rtc->max_user_freq = MAX_PERIODIC_RATE;
spin_lock_irq(&rtc_lock);
rtc1_write(ECMPLREG, 0);
rtc1_write(ECMPMREG, 0);
rtc1_write(ECMPHREG, 0);
rtc1_write(RTCL1LREG, 0);
rtc1_write(RTCL1HREG, 0);
spin_unlock_irq(&rtc_lock);
aie_irq = platform_get_irq(pdev, 0);
if (aie_irq <= 0) {
retval = -EBUSY;
goto err_iounmap_all;
}
retval = devm_request_irq(&pdev->dev, aie_irq, elapsedtime_interrupt, 0,
"elapsed_time", pdev);
if (retval < 0)
goto err_iounmap_all;
pie_irq = platform_get_irq(pdev, 1);
if (pie_irq <= 0) {
retval = -EBUSY;
goto err_iounmap_all;
}
retval = devm_request_irq(&pdev->dev, pie_irq, rtclong1_interrupt, 0,
"rtclong1", pdev);
if (retval < 0)
goto err_iounmap_all;
platform_set_drvdata(pdev, rtc);
disable_irq(aie_irq);
disable_irq(pie_irq);
dev_info(&pdev->dev, "Real Time Clock of NEC VR4100 series\n");
return 0;
err_iounmap_all:
rtc2_base = NULL;
err_rtc1_iounmap:
rtc1_base = NULL;
return retval;
}
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:RTC");
static struct platform_driver rtc_platform_driver = {
.probe = rtc_probe,
.driver = {
.name = rtc_name,
},
};
module_platform_driver(rtc_platform_driver);
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