Hi Alessandro,
On Tue, Oct 21, 2008 at 08:38:15PM +0200, Alessandro Zummo wrote:
> On Sat, 9 Aug 2008 16:14:02 +0200
> Manuel Lauss <mano@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> > It works so far on the DB1200 board; however it takes up
> > to 5 seconds until the written value actually hits the
> > register, so the hardware clock is always off (the minimum
> > seems to be 3 seconds on the DB1200). I'd like to get
> > some feedback on how to work around this "anomaly".
>
> Hi Manuel,
>
> any news on this driver? I'd need feedback from linux-mips
> to get it thru.
Here's a slightly updated version which has been running on a DB1200
demoboard for almost 2 months now. I received no feedback on the
original, unfortunately.
Thanks!
Manuel Lauss
---
From: Manuel Lauss <mano@xxxxxxxxxxxxxxxxxxxxxxx>
Date: Sat, 9 Aug 2008 15:27:55 +0200
Subject: [PATCH] RTC: Au1000 On-Chip Counter0-as-RTC driver.
Simple driver which uses the Au1xxx Time-Of-Year counter (counter0)
as a 1Hz RTC.
Signed-off-by: Manuel Lauss <mano@xxxxxxxxxxxxxxxxxxxxxxx>
---
arch/mips/alchemy/pb1200/platform.c | 6 +
drivers/rtc/Kconfig | 9 ++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-au1xxx.c | 189 +++++++++++++++++++++++++++++++++++
4 files changed, 205 insertions(+), 0 deletions(-)
create mode 100644 drivers/rtc/rtc-au1xxx.c
diff --git a/arch/mips/alchemy/pb1200/platform.c b/arch/mips/alchemy/pb1200/platform.c
index f8fb0ae..8f3bc98 100644
--- a/arch/mips/alchemy/pb1200/platform.c
+++ b/arch/mips/alchemy/pb1200/platform.c
@@ -71,7 +71,13 @@ static struct platform_device smc91c111_device = {
.resource = smc91c111_resources
};
+static struct platform_device rtc_device = {
+ .name = "rtc-au1xxx",
+ .id = -1,
+};
+
static struct platform_device *board_platform_devices[] __initdata = {
+ &rtc_device,
&ide_device,
&smc91c111_device
};
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 814f49f..0a7aac4 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -594,6 +594,15 @@ config RTC_DRV_AT91SAM9_GPBR
will be used. The default of zero is normally OK to use, but
on some systems other software needs to use that register.
+config RTC_DRV_AU1XXX
+ tristate "Au1xxx TOY-as-RTC support"
+ depends on SOC_AU1X00
+ help
+ This driver uses Au1000 on-chip Counter0 as a Real Time Clock.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-au1xxx.
+
config RTC_DRV_BFIN
tristate "Blackfin On-Chip RTC"
depends on BLACKFIN && !BF561
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index d6a9ac7..796a179 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -20,6 +20,7 @@ rtc-core-$(CONFIG_RTC_INTF_SYSFS) += rtc-sysfs.o
obj-$(CONFIG_RTC_DRV_AT32AP700X)+= rtc-at32ap700x.o
obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
obj-$(CONFIG_RTC_DRV_AT91SAM9) += rtc-at91sam9.o
+obj-$(CONFIG_RTC_DRV_AU1XXX) += rtc-au1xxx.o
obj-$(CONFIG_RTC_DRV_BFIN) += rtc-bfin.o
obj-$(CONFIG_RTC_DRV_CMOS) += rtc-cmos.o
obj-$(CONFIG_RTC_DRV_DS1216) += rtc-ds1216.o
diff --git a/drivers/rtc/rtc-au1xxx.c b/drivers/rtc/rtc-au1xxx.c
new file mode 100644
index 0000000..fb05eec
--- /dev/null
+++ b/drivers/rtc/rtc-au1xxx.c
@@ -0,0 +1,189 @@
+/*
+ * Au1xxx counter0 (aka Time-of-year counter) RTC interface driver.
+ *
+ * Copyright (C) 2008 Manuel Lauss <mano@xxxxxxxxxxxxxxxxxxxxxxx>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+/* All current Au1xxx SoCs have 2 counters fed by an external 32.768 kHz
+ * crystal. Counter 0, which keeps counting during sleep/powerdown, is
+ * used to count seconds since the beginning of the unix epoch.
+ *
+ * The counters must be configured and enabled by bootloader/board code;
+ * no checks as to whether they really get a proper 32.768kHz clock are
+ * made.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/rtc.h>
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <asm/mach-au1x00/au1000.h>
+
+/* 32kHz clock enabled and detected */
+#define CNTR_OK (SYS_CNTRL_E0 | SYS_CNTRL_32S)
+
+struct au1xtoy_rtc {
+ struct rtc_device *rtc_dev;
+ struct mutex toycnt_lock;
+};
+
+static int au1xtoy_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct au1xtoy_rtc *rtc = platform_get_drvdata(pdev);
+ unsigned long t;
+
+ if (mutex_lock_interruptible(&rtc->toycnt_lock))
+ return -ERESTARTSYS;
+
+ t = au_readl(SYS_TOYREAD);
+ mutex_unlock(&rtc->toycnt_lock);
+
+ rtc_time_to_tm(t, tm);
+
+ if (rtc_valid_tm(tm) < 0) {
+ dev_err(dev, "invalid date stored in counter0\n");
+ rtc_time_to_tm(0, tm);
+ }
+
+ return 0;
+}
+
+static int au1xtoy_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct au1xtoy_rtc *rtc = platform_get_drvdata(pdev);
+ unsigned long t;
+
+ rtc_tm_to_time(tm, &t);
+
+ if (mutex_lock_interruptible(&rtc->toycnt_lock))
+ return -ERESTARTSYS;
+
+ au_writel(t, SYS_TOYWRITE);
+ au_sync();
+
+ /* wait for the pending register write to succeed. This can
+ * take up to 6 seconds...
+ */
+ while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C0S)
+ schedule();
+
+ mutex_unlock(&rtc->toycnt_lock);
+
+ return 0;
+}
+
+static struct rtc_class_ops au1xtoy_rtc_ops = {
+ .read_time = au1xtoy_rtc_read_time,
+ .set_time = au1xtoy_rtc_set_time,
+};
+
+static int __devinit au1xtoy_rtc_probe(struct platform_device *pdev)
+{
+ struct au1xtoy_rtc *rtc;
+ unsigned long u, to;
+ int ret;
+
+ rtc = kzalloc(sizeof(struct au1xtoy_rtc), GFP_KERNEL);
+ if (unlikely(!rtc))
+ return -ENOMEM;
+
+ mutex_init(&rtc->toycnt_lock);
+
+ u = au_readl(SYS_COUNTER_CNTRL);
+ if (!(u & CNTR_OK)) {
+ dev_err(&pdev->dev, "counters not working; aborting.\n");
+ ret = -ENODEV;
+ goto out_err;
+ }
+
+ ret = -ETIMEDOUT;
+
+ /* set counter0 tickrate to 1Hz if necessary */
+ if (au_readl(SYS_TOYTRIM) != 32767) {
+ /* wait until hardware gives access to TRIM register */
+ to = 0x00100000;
+ while ((au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_T0S) && to--)
+ schedule();
+
+ if (!to) {
+ /* timed out waiting for register access; assume
+ * counters are unusable.
+ */
+ dev_err(&pdev->dev, "timeout waiting for access\n");
+ goto out_err;
+ }
+
+ /* set 1Hz TOY tick rate */
+ au_writel(32767, SYS_TOYTRIM);
+ au_sync();
+ }
+
+ /* wait until the hardware allows writes to the counter reg */
+ while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C0S)
+ schedule();
+
+ rtc->rtc_dev = rtc_device_register("rtc-au1xxx", &pdev->dev,
+ &au1xtoy_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc->rtc_dev)) {
+ ret = PTR_ERR(rtc->rtc_dev);
+ goto out_err;
+ }
+
+ platform_set_drvdata(pdev, rtc);
+
+ return 0;
+
+out_err:
+ kfree(rtc);
+ return ret;
+}
+
+static int __devexit au1xtoy_rtc_remove(struct platform_device *pdev)
+{
+ struct au1xtoy_rtc *rtc = platform_get_drvdata(pdev);
+
+ if (likely(rtc->rtc_dev))
+ rtc_device_unregister(rtc->rtc_dev);
+
+ platform_set_drvdata(pdev, NULL);
+
+ kfree(rtc);
+
+ return 0;
+}
+
+static struct platform_driver au1xtoy_rtc_platform_driver = {
+ .driver = {
+ .name = "rtc-au1xxx",
+ .owner = THIS_MODULE,
+ },
+ .probe = au1xtoy_rtc_probe,
+ .remove = __devexit_p(au1xtoy_rtc_remove),
+};
+
+static int __init au1xtoy_rtc_init(void)
+{
+ return platform_driver_register(&au1xtoy_rtc_platform_driver);
+}
+
+static void __exit au1xtoy_rtc_exit(void)
+{
+ platform_driver_unregister(&au1xtoy_rtc_platform_driver);
+}
+
+module_init(au1xtoy_rtc_init);
+module_exit(au1xtoy_rtc_exit);
+
+MODULE_DESCRIPTION("Au1xxx TOY-counter-based RTC driver");
+MODULE_AUTHOR("Manuel Lauss");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rtc-au1xxx");
--
1.6.0.2
