diff options
| -rw-r--r-- | drivers/rtc/rtc-tegra.c | 154 |
1 files changed, 79 insertions, 75 deletions
diff --git a/drivers/rtc/rtc-tegra.c b/drivers/rtc/rtc-tegra.c index f0ce76865434..a67c9d8be4f6 100644 --- a/drivers/rtc/rtc-tegra.c +++ b/drivers/rtc/rtc-tegra.c @@ -18,10 +18,10 @@ #include <linux/rtc.h> #include <linux/slab.h> -/* set to 1 = busy every eight 32kHz clocks during copy of sec+msec to AHB */ +/* Set to 1 = busy every eight 32 kHz 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. */ +/* 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 @@ -46,44 +46,48 @@ #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. */ - struct clk *clk; - int tegra_rtc_irq; /* alarm and periodic irq */ - spinlock_t tegra_rtc_lock; + struct platform_device *pdev; + struct rtc_device *rtc_dev; + void __iomem *rtc_base; /* NULL if not initialized */ + struct clk *clk; + 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. +/* + * RTC hardware is busy when it is updating its values over AHB once every + * eight 32 kHz clocks (~250 us). 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. +/* + * 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. + * AHB side) occurs every eight 32 kHz clocks (~250 us). The behavior of this + * function allows us to make some assumptions without introducing a race, + * because 250 us 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 */ - 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. */ + /* + * 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); } @@ -91,7 +95,7 @@ static int tegra_rtc_wait_while_busy(struct device *dev) return 0; retry_failed: - dev_err(dev, "write failed:retry count exceeded.\n"); + dev_err(dev, "write failed: retry count exceeded\n"); return -ETIMEDOUT; } @@ -101,8 +105,10 @@ static int tegra_rtc_read_time(struct device *dev, struct rtc_time *tm) 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. */ + /* + * 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); @@ -112,7 +118,7 @@ static int tegra_rtc_read_time(struct device *dev, struct rtc_time *tm) rtc_time64_to_tm(sec, tm); - dev_vdbg(dev, "time read as %lu. %ptR\n", sec, tm); + dev_vdbg(dev, "time read as %u, %ptR\n", sec, tm); return 0; } @@ -123,18 +129,18 @@ static int tegra_rtc_set_time(struct device *dev, struct rtc_time *tm) unsigned long sec; int ret; - /* convert tm to seconds. */ + /* convert tm to seconds */ sec = rtc_tm_to_time64(tm); - dev_vdbg(dev, "time set to %lu. %ptR\n", sec, tm); + dev_vdbg(dev, "time set to %u, %ptR\n", sec, tm); - /* seconds only written if wait succeeded. */ + /* 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)); + readl(info->rtc_base + TEGRA_RTC_REG_SECONDS)); return ret; } @@ -143,15 +149,15 @@ 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; + unsigned int tmp; sec = readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0); if (sec == 0) { - /* alarm is disabled. */ + /* alarm is disabled */ alarm->enabled = 0; } else { - /* alarm is enabled. */ + /* alarm is enabled */ alarm->enabled = 1; rtc_time64_to_tm(sec, &alarm->time); } @@ -165,13 +171,13 @@ static int tegra_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) 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; + unsigned int status; 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. */ + /* 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 */ @@ -198,14 +204,14 @@ static int tegra_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) 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)); + 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. %ptR\n", sec, &alarm->time); + dev_vdbg(dev, "alarm set as %u, %ptR\n", sec, &alarm->time); } else { - /* disable alarm if 0 or write error. */ + /* disable alarm if 0 or write error */ dev_vdbg(dev, "alarm disabled\n"); tegra_rtc_alarm_irq_enable(dev, 0); } @@ -228,25 +234,26 @@ 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; + unsigned int status; status = readl(info->rtc_base + TEGRA_RTC_REG_INTR_STATUS); if (status) { - /* clear the interrupt masks and status on any irq. */ + /* 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)) + /* 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)) + /* 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); @@ -255,11 +262,11 @@ static irqreturn_t tegra_rtc_irq_handler(int irq, void *data) } static const 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, + .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, }; @@ -275,8 +282,7 @@ static int __init tegra_rtc_probe(struct platform_device *pdev) struct resource *res; int ret; - info = devm_kzalloc(&pdev->dev, sizeof(struct tegra_rtc_info), - GFP_KERNEL); + info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL); if (!info) return -ENOMEM; @@ -308,13 +314,13 @@ static int __init tegra_rtc_probe(struct platform_device *pdev) if (ret < 0) return ret; - /* set context info. */ + /* set context info */ info->pdev = pdev; spin_lock_init(&info->tegra_rtc_lock); platform_set_drvdata(pdev, info); - /* clear out the hardware. */ + /* 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); @@ -322,19 +328,16 @@ static int __init tegra_rtc_probe(struct platform_device *pdev) device_init_wakeup(&pdev->dev, 1); ret = devm_request_irq(&pdev->dev, info->tegra_rtc_irq, - tegra_rtc_irq_handler, IRQF_TRIGGER_HIGH, - dev_name(&pdev->dev), &pdev->dev); + tegra_rtc_irq_handler, IRQF_TRIGGER_HIGH, + dev_name(&pdev->dev), &pdev->dev); if (ret) { - dev_err(&pdev->dev, - "Unable to request interrupt for device (err=%d).\n", - ret); + dev_err(&pdev->dev, "failed to request interrupt: %d\n", ret); goto disable_clk; } ret = rtc_register_device(info->rtc_dev); if (ret) { - dev_err(&pdev->dev, "Unable to register device (err=%d).\n", - ret); + dev_err(&pdev->dev, "failed to register device: %d\n", ret); goto disable_clk; } @@ -363,18 +366,18 @@ static int tegra_rtc_suspend(struct device *dev) tegra_rtc_wait_while_busy(dev); - /* only use ALARM0 as a wake source. */ + /* 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)); + 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); + 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. */ + /* leave the alarms on as a wake source */ if (device_may_wakeup(dev)) enable_irq_wake(info->tegra_rtc_irq); @@ -386,8 +389,9 @@ static int tegra_rtc_resume(struct device *dev) struct tegra_rtc_info *info = dev_get_drvdata(dev); dev_vdbg(dev, "Resume (device_may_wakeup=%d)\n", - device_may_wakeup(dev)); - /* alarms were left on as a wake source, turn them off. */ + 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); @@ -399,18 +403,17 @@ static SIMPLE_DEV_PM_OPS(tegra_rtc_pm_ops, tegra_rtc_suspend, tegra_rtc_resume); static void tegra_rtc_shutdown(struct platform_device *pdev) { - dev_vdbg(&pdev->dev, "disabling interrupts.\n"); + 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", + .remove = tegra_rtc_remove, + .shutdown = tegra_rtc_shutdown, + .driver = { + .name = "tegra_rtc", .of_match_table = tegra_rtc_dt_match, - .pm = &tegra_rtc_pm_ops, + .pm = &tegra_rtc_pm_ops, }, }; @@ -418,4 +421,5 @@ module_platform_driver_probe(tegra_rtc_driver, tegra_rtc_probe); MODULE_AUTHOR("Jon Mayo <jmayo@nvidia.com>"); MODULE_DESCRIPTION("driver for Tegra internal RTC"); +MODULE_ALIAS("platform:tegra_rtc"); MODULE_LICENSE("GPL"); |