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authorAndrew Lunn <andrew@lunn.ch>2013-02-03 15:32:06 +0400
committerJason Cooper <jason@lakedaemon.net>2013-03-09 01:34:41 +0400
commit89c58c198b252f2bc20657fdd72a2aea788c435c (patch)
tree735d8844993deb5a8d39efb171db8331241ce547 /drivers/rtc/rtc-mv.c
parentde88747f514a4e0cca416a8871de2302f4f77790 (diff)
downloadlinux-89c58c198b252f2bc20657fdd72a2aea788c435c.tar.xz
rtc: rtc-mv: Add support for clk to avoid lockups
The Marvell RTC on Kirkwood makes use of the runit clock. Ensure the driver clk_prepare_enable() this clock, otherwise there is a danger the SoC will lockup when accessing RTC registers with the clock disabled. Reported-by: Simon Baatz <gmbnomis@gmail.com> Signed-off-by: Andrew Lunn <andrew@lunn.ch> Tested-by: Simon Baatz <gmbnomis@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Diffstat (limited to 'drivers/rtc/rtc-mv.c')
-rw-r--r--drivers/rtc/rtc-mv.c28
1 files changed, 24 insertions, 4 deletions
diff --git a/drivers/rtc/rtc-mv.c b/drivers/rtc/rtc-mv.c
index 57233c885998..8f87fec27ce7 100644
--- a/drivers/rtc/rtc-mv.c
+++ b/drivers/rtc/rtc-mv.c
@@ -14,6 +14,7 @@
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/delay.h>
+#include <linux/clk.h>
#include <linux/gfp.h>
#include <linux/module.h>
@@ -41,6 +42,7 @@ struct rtc_plat_data {
struct rtc_device *rtc;
void __iomem *ioaddr;
int irq;
+ struct clk *clk;
};
static int mv_rtc_set_time(struct device *dev, struct rtc_time *tm)
@@ -221,6 +223,7 @@ static int mv_rtc_probe(struct platform_device *pdev)
struct rtc_plat_data *pdata;
resource_size_t size;
u32 rtc_time;
+ int ret = 0;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
@@ -239,11 +242,17 @@ static int mv_rtc_probe(struct platform_device *pdev)
if (!pdata->ioaddr)
return -ENOMEM;
+ pdata->clk = devm_clk_get(&pdev->dev, NULL);
+ /* Not all SoCs require a clock.*/
+ if (!IS_ERR(pdata->clk))
+ clk_prepare_enable(pdata->clk);
+
/* make sure the 24 hours mode is enabled */
rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
if (rtc_time & RTC_HOURS_12H_MODE) {
dev_err(&pdev->dev, "24 Hours mode not supported.\n");
- return -EINVAL;
+ ret = -EINVAL;
+ goto out;
}
/* make sure it is actually functional */
@@ -252,7 +261,8 @@ static int mv_rtc_probe(struct platform_device *pdev)
rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
if (rtc_time == 0x01000000) {
dev_err(&pdev->dev, "internal RTC not ticking\n");
- return -ENODEV;
+ ret = -ENODEV;
+ goto out;
}
}
@@ -268,8 +278,10 @@ static int mv_rtc_probe(struct platform_device *pdev)
} else
pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,
&mv_rtc_ops, THIS_MODULE);
- if (IS_ERR(pdata->rtc))
- return PTR_ERR(pdata->rtc);
+ if (IS_ERR(pdata->rtc)) {
+ ret = PTR_ERR(pdata->rtc);
+ goto out;
+ }
if (pdata->irq >= 0) {
writel(0, pdata->ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
@@ -282,6 +294,11 @@ static int mv_rtc_probe(struct platform_device *pdev)
}
return 0;
+out:
+ if (!IS_ERR(pdata->clk))
+ clk_disable_unprepare(pdata->clk);
+
+ return ret;
}
static int __exit mv_rtc_remove(struct platform_device *pdev)
@@ -292,6 +309,9 @@ static int __exit mv_rtc_remove(struct platform_device *pdev)
device_init_wakeup(&pdev->dev, 0);
rtc_device_unregister(pdata->rtc);
+ if (!IS_ERR(pdata->clk))
+ clk_disable_unprepare(pdata->clk);
+
return 0;
}