q3k/linux
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
linux/drivers/rtc/rtc-tegra.c
Joseph Lo 2d79cf8a9d drivers/rtc/rtc-tegra.c: convert to DT driver 
After Kernel 3.7, the Tegra device will only support booting with DT.
The legacy Tegra RTC platform driver will not work anymore.  This patch
converts the driver to support DT.

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-04 16:11:45 -08:00

471 lines
13 KiB
C
Raw Blame History

/*
* An RTC driver for the NVIDIA Tegra 200 series internal RTC.
*
* Copyright (c) 2010, NVIDIA Corporation.
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
/* set to 1 = busy every eight 32kHz clocks during copy of sec+msec to AHB */
#define TEGRA_RTC_REG_BUSY 0x004
#define TEGRA_RTC_REG_SECONDS 0x008
/* when msec is read, the seconds are buffered into shadow seconds. */
#define TEGRA_RTC_REG_SHADOW_SECONDS 0x00c
#define TEGRA_RTC_REG_MILLI_SECONDS 0x010
#define TEGRA_RTC_REG_SECONDS_ALARM0 0x014
#define TEGRA_RTC_REG_SECONDS_ALARM1 0x018
#define TEGRA_RTC_REG_MILLI_SECONDS_ALARM0 0x01c
#define TEGRA_RTC_REG_INTR_MASK 0x028
/* write 1 bits to clear status bits */
#define TEGRA_RTC_REG_INTR_STATUS 0x02c
/* bits in INTR_MASK */
#define TEGRA_RTC_INTR_MASK_MSEC_CDN_ALARM (1<<4)
#define TEGRA_RTC_INTR_MASK_SEC_CDN_ALARM (1<<3)
#define TEGRA_RTC_INTR_MASK_MSEC_ALARM (1<<2)
#define TEGRA_RTC_INTR_MASK_SEC_ALARM1 (1<<1)
#define TEGRA_RTC_INTR_MASK_SEC_ALARM0 (1<<0)
/* bits in INTR_STATUS */
#define TEGRA_RTC_INTR_STATUS_MSEC_CDN_ALARM (1<<4)
#define TEGRA_RTC_INTR_STATUS_SEC_CDN_ALARM (1<<3)
#define TEGRA_RTC_INTR_STATUS_MSEC_ALARM (1<<2)
#define TEGRA_RTC_INTR_STATUS_SEC_ALARM1 (1<<1)
#define TEGRA_RTC_INTR_STATUS_SEC_ALARM0 (1<<0)
struct tegra_rtc_info {
struct platform_device *pdev;
struct rtc_device *rtc_dev;
void __iomem *rtc_base; /* NULL if not initialized. */
int tegra_rtc_irq; /* alarm and periodic irq */
spinlock_t tegra_rtc_lock;
};
/* RTC hardware is busy when it is updating its values over AHB once
* every eight 32kHz clocks (~250uS).
* outside of these updates the CPU is free to write.
* CPU is always free to read.
*/
static inline u32 tegra_rtc_check_busy(struct tegra_rtc_info *info)
{
return readl(info->rtc_base + TEGRA_RTC_REG_BUSY) & 1;
}
/* Wait for hardware to be ready for writing.
* This function tries to maximize the amount of time before the next update.
* It does this by waiting for the RTC to become busy with its periodic update,
* then returning once the RTC first becomes not busy.
* This periodic update (where the seconds and milliseconds are copied to the
* AHB side) occurs every eight 32kHz clocks (~250uS).
* The behavior of this function allows us to make some assumptions without
* introducing a race, because 250uS is plenty of time to read/write a value.
*/
static int tegra_rtc_wait_while_busy(struct device *dev)
{
struct tegra_rtc_info *info = dev_get_drvdata(dev);
int retries = 500; /* ~490 us is the worst case, ~250 us is best. */
/* first wait for the RTC to become busy. this is when it
* posts its updated seconds+msec registers to AHB side. */
while (tegra_rtc_check_busy(info)) {
if (!retries--)
goto retry_failed;
udelay(1);
}
/* now we have about 250 us to manipulate registers */
return 0;
retry_failed:
dev_err(dev, "write failed:retry count exceeded.\n");
return -ETIMEDOUT;
}
static int tegra_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct tegra_rtc_info *info = dev_get_drvdata(dev);
unsigned long sec, msec;
unsigned long sl_irq_flags;
/* RTC hardware copies seconds to shadow seconds when a read
* of milliseconds occurs. use a lock to keep other threads out. */
spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags);
msec = readl(info->rtc_base + TEGRA_RTC_REG_MILLI_SECONDS);
sec = readl(info->rtc_base + TEGRA_RTC_REG_SHADOW_SECONDS);
spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags);
rtc_time_to_tm(sec, tm);
dev_vdbg(dev, "time read as %lu. %d/%d/%d %d:%02u:%02u\n",
sec,
tm->tm_mon + 1,
tm->tm_mday,
tm->tm_year + 1900,
tm->tm_hour,
tm->tm_min,
tm->tm_sec
);
return 0;
}
static int tegra_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct tegra_rtc_info *info = dev_get_drvdata(dev);
unsigned long sec;
int ret;
/* convert tm to seconds. */
ret = rtc_valid_tm(tm);
if (ret)
return ret;
rtc_tm_to_time(tm, &sec);
dev_vdbg(dev, "time set to %lu. %d/%d/%d %d:%02u:%02u\n",
sec,
tm->tm_mon+1,
tm->tm_mday,
tm->tm_year+1900,
tm->tm_hour,
tm->tm_min,
tm->tm_sec
);
/* seconds only written if wait succeeded. */
ret = tegra_rtc_wait_while_busy(dev);
if (!ret)
writel(sec, info->rtc_base + TEGRA_RTC_REG_SECONDS);
dev_vdbg(dev, "time read back as %d\n",
readl(info->rtc_base + TEGRA_RTC_REG_SECONDS));
return ret;
}
static int tegra_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct tegra_rtc_info *info = dev_get_drvdata(dev);
unsigned long sec;
unsigned tmp;
sec = readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0);
if (sec == 0) {
/* alarm is disabled. */
alarm->enabled = 0;
alarm->time.tm_mon = -1;
alarm->time.tm_mday = -1;
alarm->time.tm_year = -1;
alarm->time.tm_hour = -1;
alarm->time.tm_min = -1;
alarm->time.tm_sec = -1;
} else {
/* alarm is enabled. */
alarm->enabled = 1;
rtc_time_to_tm(sec, &alarm->time);
}
tmp = readl(info->rtc_base + TEGRA_RTC_REG_INTR_STATUS);
alarm->pending = (tmp & TEGRA_RTC_INTR_STATUS_SEC_ALARM0) != 0;
return 0;
}
static int tegra_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct tegra_rtc_info *info = dev_get_drvdata(dev);
unsigned status;
unsigned long sl_irq_flags;
tegra_rtc_wait_while_busy(dev);
spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags);
/* read the original value, and OR in the flag. */
status = readl(info->rtc_base + TEGRA_RTC_REG_INTR_MASK);
if (enabled)
status |= TEGRA_RTC_INTR_MASK_SEC_ALARM0; /* set it */
else
status &= ~TEGRA_RTC_INTR_MASK_SEC_ALARM0; /* clear it */
writel(status, info->rtc_base + TEGRA_RTC_REG_INTR_MASK);
spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags);
return 0;
}
static int tegra_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct tegra_rtc_info *info = dev_get_drvdata(dev);
unsigned long sec;
if (alarm->enabled)
rtc_tm_to_time(&alarm->time, &sec);
else
sec = 0;
tegra_rtc_wait_while_busy(dev);
writel(sec, info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0);
dev_vdbg(dev, "alarm read back as %d\n",
readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0));
/* if successfully written and alarm is enabled ... */
if (sec) {
tegra_rtc_alarm_irq_enable(dev, 1);
dev_vdbg(dev, "alarm set as %lu. %d/%d/%d %d:%02u:%02u\n",
sec,
alarm->time.tm_mon+1,
alarm->time.tm_mday,
alarm->time.tm_year+1900,
alarm->time.tm_hour,
alarm->time.tm_min,
alarm->time.tm_sec);
} else {
/* disable alarm if 0 or write error. */
dev_vdbg(dev, "alarm disabled\n");
tegra_rtc_alarm_irq_enable(dev, 0);
}
return 0;
}
static int tegra_rtc_proc(struct device *dev, struct seq_file *seq)
{
if (!dev || !dev->driver)
return 0;
return seq_printf(seq, "name\t\t: %s\n", dev_name(dev));
}
static irqreturn_t tegra_rtc_irq_handler(int irq, void *data)
{
struct device *dev = data;
struct tegra_rtc_info *info = dev_get_drvdata(dev);
unsigned long events = 0;
unsigned status;
unsigned long sl_irq_flags;
status = readl(info->rtc_base + TEGRA_RTC_REG_INTR_STATUS);
if (status) {
/* clear the interrupt masks and status on any irq. */
tegra_rtc_wait_while_busy(dev);
spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags);
writel(0, info->rtc_base + TEGRA_RTC_REG_INTR_MASK);
writel(status, info->rtc_base + TEGRA_RTC_REG_INTR_STATUS);
spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags);
}
/* check if Alarm */
if ((status & TEGRA_RTC_INTR_STATUS_SEC_ALARM0))
events |= RTC_IRQF | RTC_AF;
/* check if Periodic */
if ((status & TEGRA_RTC_INTR_STATUS_SEC_CDN_ALARM))
events |= RTC_IRQF | RTC_PF;
rtc_update_irq(info->rtc_dev, 1, events);
return IRQ_HANDLED;
}
static struct rtc_class_ops tegra_rtc_ops = {
.read_time = tegra_rtc_read_time,
.set_time = tegra_rtc_set_time,
.read_alarm = tegra_rtc_read_alarm,
.set_alarm = tegra_rtc_set_alarm,
.proc = tegra_rtc_proc,
.alarm_irq_enable = tegra_rtc_alarm_irq_enable,
};
static const struct of_device_id tegra_rtc_dt_match[] = {
{ .compatible = "nvidia,tegra20-rtc", },
{}
};
MODULE_DEVICE_TABLE(of, tegra_rtc_dt_match);
static int tegra_rtc_probe(struct platform_device *pdev)
{
struct tegra_rtc_info *info;
struct resource *res;
int ret;
info = devm_kzalloc(&pdev->dev, sizeof(struct tegra_rtc_info),
GFP_KERNEL);
if (!info)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev,
"Unable to allocate resources for device.\n");
return -EBUSY;
}
info->rtc_base = devm_request_and_ioremap(&pdev->dev, res);
if (!info->rtc_base) {
dev_err(&pdev->dev, "Unable to request mem region and grab IOs for device.\n");
return -EBUSY;
}
info->tegra_rtc_irq = platform_get_irq(pdev, 0);
if (info->tegra_rtc_irq <= 0)
return -EBUSY;
/* set context info. */
info->pdev = pdev;
spin_lock_init(&info->tegra_rtc_lock);
platform_set_drvdata(pdev, info);
/* clear out the hardware. */
writel(0, info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0);
writel(0xffffffff, info->rtc_base + TEGRA_RTC_REG_INTR_STATUS);
writel(0, info->rtc_base + TEGRA_RTC_REG_INTR_MASK);
device_init_wakeup(&pdev->dev, 1);
info->rtc_dev = rtc_device_register(
pdev->name, &pdev->dev, &tegra_rtc_ops, THIS_MODULE);
if (IS_ERR(info->rtc_dev)) {
ret = PTR_ERR(info->rtc_dev);
info->rtc_dev = NULL;
dev_err(&pdev->dev,
"Unable to register device (err=%d).\n",
ret);
return ret;
}
ret = devm_request_irq(&pdev->dev, info->tegra_rtc_irq,
tegra_rtc_irq_handler, IRQF_TRIGGER_HIGH,
"rtc alarm", &pdev->dev);
if (ret) {
dev_err(&pdev->dev,
"Unable to request interrupt for device (err=%d).\n",
ret);
goto err_dev_unreg;
}
dev_notice(&pdev->dev, "Tegra internal Real Time Clock\n");
return 0;
err_dev_unreg:
rtc_device_unregister(info->rtc_dev);
return ret;
}
static int tegra_rtc_remove(struct platform_device *pdev)
{
struct tegra_rtc_info *info = platform_get_drvdata(pdev);
rtc_device_unregister(info->rtc_dev);
platform_set_drvdata(pdev, NULL);
return 0;
}
#ifdef CONFIG_PM
static int tegra_rtc_suspend(struct platform_device *pdev, pm_message_t state)
{
struct device *dev = &pdev->dev;
struct tegra_rtc_info *info = platform_get_drvdata(pdev);
tegra_rtc_wait_while_busy(dev);
/* only use ALARM0 as a wake source. */
writel(0xffffffff, info->rtc_base + TEGRA_RTC_REG_INTR_STATUS);
writel(TEGRA_RTC_INTR_STATUS_SEC_ALARM0,
info->rtc_base + TEGRA_RTC_REG_INTR_MASK);
dev_vdbg(dev, "alarm sec = %d\n",
readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0));
dev_vdbg(dev, "Suspend (device_may_wakeup=%d) irq:%d\n",
device_may_wakeup(dev), info->tegra_rtc_irq);
/* leave the alarms on as a wake source. */
if (device_may_wakeup(dev))
enable_irq_wake(info->tegra_rtc_irq);
return 0;
}
static int tegra_rtc_resume(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct tegra_rtc_info *info = platform_get_drvdata(pdev);
dev_vdbg(dev, "Resume (device_may_wakeup=%d)\n",
device_may_wakeup(dev));
/* alarms were left on as a wake source, turn them off. */
if (device_may_wakeup(dev))
disable_irq_wake(info->tegra_rtc_irq);
return 0;
}
#endif
static void tegra_rtc_shutdown(struct platform_device *pdev)
{
dev_vdbg(&pdev->dev, "disabling interrupts.\n");
tegra_rtc_alarm_irq_enable(&pdev->dev, 0);
}
MODULE_ALIAS("platform:tegra_rtc");
static struct platform_driver tegra_rtc_driver = {
.remove = tegra_rtc_remove,
.shutdown = tegra_rtc_shutdown,
.driver = {
.name = "tegra_rtc",
.owner = THIS_MODULE,
.of_match_table = tegra_rtc_dt_match,
},
#ifdef CONFIG_PM
.suspend = tegra_rtc_suspend,
.resume = tegra_rtc_resume,
#endif
};
static int __init tegra_rtc_init(void)
{
return platform_driver_probe(&tegra_rtc_driver, tegra_rtc_probe);
}
module_init(tegra_rtc_init);
static void __exit tegra_rtc_exit(void)
{
platform_driver_unregister(&tegra_rtc_driver);
}
module_exit(tegra_rtc_exit);
MODULE_AUTHOR("Jon Mayo <jmayo@nvidia.com>");
MODULE_DESCRIPTION("driver for Tegra internal RTC");
MODULE_LICENSE("GPL");
Reference in a new issue View git blame Copy permalink