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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>
This commit is contained in:
Andrew Lunn 2013-02-03 12:32:06 +01:00 committed by Jason Cooper
parent de88747f51
commit 89c58c198b
2 changed files with 25 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/arm/boot/dts/kirkwood.dtsi
View File

@ -75,6 +75,7 @@
compatible = "marvell,kirkwood-rtc", "marvell,orion-rtc";
reg = <0x10300 0x20>;
interrupts = <53>;
clocks = <&gate_clk 7>;
};
spi@10600 {

28
drivers/rtc/rtc-mv.c
View File

@ -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;
}