Messages in this thread | | | Date | Thu, 14 Oct 2010 11:36:43 +0800 | Subject | Re: [rtc-linux] [PATCH 1/1] rtc: Add real-time clock driver for Tegra. | From | Wan ZongShun <> |
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Hi Andrew Chew ,
I have a quick look for your patch, Few comments below:
2010/10/14 <achew@nvidia.com>: > From: Andrew Chew <achew@nvidia.com> > > This is a platform driver that supports the built-in real-time clock on > Tegra SOCs. > > Signed-off-by: Andrew Chew <achew@nvidia.com> > --- > drivers/rtc/Kconfig | 10 + > drivers/rtc/Makefile | 1 + > drivers/rtc/rtc-tegra.c | 520 +++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 531 insertions(+), 0 deletions(-) > create mode 100644 drivers/rtc/rtc-tegra.c > > diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig > index 2432541..ca0da79 100644 > --- a/drivers/rtc/Kconfig > +++ b/drivers/rtc/Kconfig > @@ -963,4 +963,14 @@ config RTC_DRV_JZ4740 > This driver can also be buillt as a module. If so, the module > will be called rtc-jz4740. > > +config RTC_DRV_TEGRA > + tristate "NVIDIA Tegra Internal RTC driver" > + depends on RTC_CLASS && ARCH_TEGRA > + help > + If you say yes here you get support for the > + Tegra 200 series internal RTC module. > + > + This drive can also be built as a module. If so, the module > + will be called rtc-tegra. > + > endif # RTC_CLASS > diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile > index 4ff4b88..a7f3617 100644 > --- a/drivers/rtc/Makefile > +++ b/drivers/rtc/Makefile > @@ -91,6 +91,7 @@ obj-$(CONFIG_RTC_DRV_STARFIRE) += rtc-starfire.o > obj-$(CONFIG_RTC_DRV_STK17TA8) += rtc-stk17ta8.o > obj-$(CONFIG_RTC_DRV_STMP) += rtc-stmp3xxx.o > obj-$(CONFIG_RTC_DRV_SUN4V) += rtc-sun4v.o > +obj-$(CONFIG_RTC_DRV_TEGRA) += rtc-tegra.o > obj-$(CONFIG_RTC_DRV_TEST) += rtc-test.o > obj-$(CONFIG_RTC_DRV_TWL4030) += rtc-twl.o > obj-$(CONFIG_RTC_DRV_TX4939) += rtc-tx4939.o > diff --git a/drivers/rtc/rtc-tegra.c b/drivers/rtc/rtc-tegra.c > new file mode 100644 > index 0000000..79054d1 > --- /dev/null > +++ b/drivers/rtc/rtc-tegra.c > @@ -0,0 +1,520 @@ > +/* > + * An RTC driver for the NVIDIA Tegra 200 series internal RTC. > + * > + * Copyright (c) 2010, NVIDIA Corporation. > + * Copyright (c) 2010 Jon Mayo <jmayo@nvidia.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. > + * > + * 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> > + > +/* how many attempts to wait in tegra_rtc_wait_while_busy(). */ > +#define RTC_TEGRA_RETRIES 15 > + > +/* STATUS: This bit is set when a write is initiated on the APB side. It is > + * cleared once the write completes in RTC 32KHz clock domain which could be > + * several thousands of APB clocks. This must be IDLE before a write is > + * initiated. Note that this bit is only for writes. > + * 0 = IDLE > + * 1 = BUSY > + */ > +#define RTC_TEGRA_REG_BUSY 0x004 > +#define RTC_TEGRA_REG_SECONDS 0x008 > +#define RTC_TEGRA_REG_SHADOW_SECONDS 0x00c > +#define RTC_TEGRA_REG_MILLI_SECONDS 0x010 > +#define RTC_TEGRA_REG_SECONDS_ALARM0 0x014 > +#define RTC_TEGRA_REG_SECONDS_ALARM1 0x018 > +#define RTC_TEGRA_REG_MILLI_SECONDS_ALARM0 0x01c > +#define RTC_TEGRA_REG_INTR_MASK 0x028 > +/* a write to this register performs a clear. reg=reg&(~x) */ > +#define RTC_TEGRA_REG_INTR_STATUS 0x02c > + > +/* bits in INTR_MASK */ > +#define RTC_TEGRA_INTR_MASK_MSEC_CDN_ALARM (1<<4) > +#define RTC_TEGRA_INTR_MASK_SEC_CDN_ALARM (1<<3) > +#define RTC_TEGRA_INTR_MASK_MSEC_ALARM (1<<2) > +#define RTC_TEGRA_INTR_MASK_SEC_ALARM1 (1<<1) > +#define RTC_TEGRA_INTR_MASK_SEC_ALARM0 (1<<0) > + > +/* bits in INTR_STATUS */ > +#define RTC_TEGRA_INTR_STATUS_MSEC_CDN_ALARM (1<<4) > +#define RTC_TEGRA_INTR_STATUS_SEC_CDN_ALARM (1<<3) > +#define RTC_TEGRA_INTR_STATUS_MSEC_ALARM (1<<2) > +#define RTC_TEGRA_INTR_STATUS_SEC_ALARM1 (1<<1) > +#define RTC_TEGRA_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; > +}; > + > +/* check is hardware is accessing APB. */ > +static inline u32 tegra_rtc_check_busy(struct tegra_rtc_info *info) > +{ > + return readl(info->rtc_base + RTC_TEGRA_REG_BUSY); > +} > + > +/* wait for hardware to be ready for writing. > + * do not call this inside the spin lock because it sleeps. > + */ > +static int tegra_rtc_wait_while_busy(struct device *dev) > +{ > + struct tegra_rtc_info *info = dev_get_drvdata(dev); > + > + /* TODO: wait for busy then not busy to catch a leading edge. */ > + int retries = RTC_TEGRA_RETRIES; > + > + while (tegra_rtc_check_busy(info)) { > + if (!retries--) { > + dev_err(dev, "write failed:retry count exceeded.\n"); > + return -ETIMEDOUT; > + } > + msleep(1); > + } > + > + return 0; > +} > + > +/* waits for the RTC to not be busy accessing APB, then write a single value. */ > +static int tegra_rtc_write_not_busy(struct device *dev, unsigned ofs, u32 value) > +{ > + struct tegra_rtc_info *info = dev_get_drvdata(dev); > + unsigned long sl_irq_flags; > + int ret; > + > + spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags); > + > + if (tegra_rtc_check_busy(info)) { > + spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags); > + ret = tegra_rtc_wait_while_busy(dev); > + if (ret) > + return ret; > + spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags); > + } > + > + writel(value, info->rtc_base + ofs); > + > + spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags); > + > + return 0; > +} > + > + > +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; > + > + spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags); > + > + msec = readl(info->rtc_base + RTC_TEGRA_REG_MILLI_SECONDS); > + sec = readl(info->rtc_base + RTC_TEGRA_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 < 0) > + 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_write_not_busy(dev, RTC_TEGRA_REG_SECONDS, sec); > + > + dev_vdbg(dev, "time read back as %d\n", > + readl(info->rtc_base + RTC_TEGRA_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 long sl_irq_flags; > + unsigned tmp; > + > + spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags); > + > + sec = readl(info->rtc_base + RTC_TEGRA_REG_SECONDS_ALARM0); > + > + spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags); > + > + 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 + RTC_TEGRA_REG_INTR_STATUS); > + alarm->pending = (tmp & RTC_TEGRA_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; > + int ret; > + > + spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags); > + > + if (tegra_rtc_check_busy(info)) { /* wait for the busy bit to clear. */ > + spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags); > + ret = tegra_rtc_wait_while_busy(dev); > + if (ret) > + return ret; > + spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags); > + } > + > + /* read the original value, and OR in the flag. */ > + status = readl(info->rtc_base + RTC_TEGRA_REG_INTR_MASK); > + if (enabled) > + status |= RTC_TEGRA_INTR_MASK_SEC_ALARM0; /* set it */ > + else > + status &= ~RTC_TEGRA_INTR_MASK_SEC_ALARM0; /* clear it */ > + > + writel(status, info->rtc_base + RTC_TEGRA_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); > + int ret; > + unsigned long sec; > + > + if (alarm->enabled) > + rtc_tm_to_time(&alarm->time, &sec); > + else > + sec = 0; > + > + ret = tegra_rtc_write_not_busy(dev, RTC_TEGRA_REG_SECONDS_ALARM0, sec); > + dev_vdbg(dev, "alarm read back as %d\n", > + readl(info->rtc_base + RTC_TEGRA_REG_SECONDS_ALARM0)); > + > + /* if successfully written and alarm is enabled ... */ > + if ((ret == 0) && 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 ret; > +} > + > +static int tegra_rtc_ioctl( > + struct device *dev, unsigned int cmd, unsigned long arg) > +{ > + /* use default ioctl handlers for: > + * RTC_RD_TIME, RTC_SET_TIME, RTC_ALM_SET, RTC_ALM_READ, RTC_WKALM_SET, > + * RTC_WKALM_RD, RTC_IRQP_SET, RTC_IRQP_READ, RTC_PIE_ON, RTC_PIE_OFF > + */ > + return -ENOIOCTLCMD; > +}
The function is redundant here.
> + > +/* additional proc lines. */ > +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 + RTC_TEGRA_REG_INTR_STATUS); > + if (status) { > + /* clear the interrupt masks and status on any irq. */ > + spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags); > + writel(0, info->rtc_base + RTC_TEGRA_REG_INTR_MASK); > + writel(0xffffffff, info->rtc_base + RTC_TEGRA_REG_INTR_STATUS); > + spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags); > + } > + > + /* check if Alarm */ > + if ((status & RTC_TEGRA_INTR_STATUS_SEC_ALARM0)) > + events |= RTC_IRQF | RTC_AF; > + > + /* check if Periodic */ > + if ((status & RTC_TEGRA_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 = { > + .ioctl = tegra_rtc_ioctl,
There is no need to put it here.
> + .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 int __init tegra_rtc_probe(struct platform_device *pdev)
__devinit ?
> +{ > + struct tegra_rtc_info *info; > + struct resource *res; > + int ret; > + > + info = kzalloc(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"); > + ret = -EBUSY; > + goto err_free_info; > + } > + > + info->tegra_rtc_irq = platform_get_irq(pdev, 0); > + if (info->tegra_rtc_irq <= 0) { > + ret = -EBUSY; > + goto err_free_info; > + } > + > + info->rtc_base = ioremap(res->start, res->end - res->start + 1); > + if (!info->rtc_base) { > + dev_err(&pdev->dev, "Unable to grab IOs for device.\n"); > + ret = -EBUSY; > + goto err_free_info; > + } > + > + /* set context info. */ > + info->pdev = pdev; > + info->tegra_rtc_lock = __SPIN_LOCK_UNLOCKED(info->tegra_rtc_lock); > + > + platform_set_drvdata(pdev, info); > + > + /* clear out the hardware. */ > + tegra_rtc_write_not_busy(&pdev->dev, RTC_TEGRA_REG_SECONDS_ALARM0, 0); > + tegra_rtc_write_not_busy(&pdev->dev, RTC_TEGRA_REG_INTR_STATUS, > + 0xffffffff); > + tegra_rtc_write_not_busy(&pdev->dev, RTC_TEGRA_REG_INTR_MASK, 0); > + > + 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); > + goto err_iounmap; > + } > + > + ret = request_irq(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); > +err_iounmap: > + iounmap(info->rtc_base); > +err_free_info: > + kfree(info); > + > + return ret; > +} > + > +static int __devexit tegra_rtc_remove(struct platform_device *pdev) > +{ > + struct tegra_rtc_info *info = platform_get_drvdata(pdev); > + > + free_irq(info->tegra_rtc_irq, &pdev->dev); > + rtc_device_unregister(info->rtc_dev); > + iounmap(info->rtc_base); > + kfree(info); > + > + 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); > + > + /* only use ALARM0 as a wake source. */ > + writel(0xffffffff, info->rtc_base + RTC_TEGRA_REG_INTR_STATUS); > + writel(RTC_TEGRA_INTR_STATUS_SEC_ALARM0, > + info->rtc_base + RTC_TEGRA_REG_INTR_MASK); > + > + dev_vdbg(dev, "alarm sec = %d\n", > + readl(info->rtc_base + RTC_TEGRA_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); > + unsigned int intr_status; > + > + /* clear */ > + intr_status = readl(info->rtc_base + RTC_TEGRA_REG_INTR_STATUS); > + if (intr_status & RTC_TEGRA_INTR_STATUS_SEC_ALARM0) { > + tegra_rtc_write_not_busy(dev, RTC_TEGRA_REG_INTR_MASK, 0); > + tegra_rtc_write_not_busy(dev, RTC_TEGRA_REG_INTR_STATUS, > + 0xffffffff); > + } > + > + 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 = __devexit_p(tegra_rtc_remove), > + .shutdown = tegra_rtc_shutdown, > + .driver = { > + .name = "tegra_rtc", > + .owner = THIS_MODULE, > + }, > +#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_DESCRIPTION("driver for Tegra internal RTC"); > +MODULE_LICENSE("GPL"); > -- > 1.7.0.4 > > -- > You received this message because you are subscribed to "rtc-linux". > Membership options at http://groups.google.com/group/rtc-linux . > Please read http://groups.google.com/group/rtc-linux/web/checklist > before submitting a driver.
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