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ARM: 8201/1: amba: Don't unprepare the clocks if device driver wants IRQ safe runtime PM v12

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The AMBA bus driver defines runtime Power Management functions which
disable and unprepare AMBA bus clock. This is problematic for runtime PM
because unpreparing a clock might sleep so it is not interrupt safe.

However some drivers may want to implement runtime PM functions in
interrupt-safe way (see pm_runtime_irq_safe()). In such case the AMBA
bus driver should only disable/enable the clock in runtime suspend and
resume callbacks.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Krzysztof Kozlowski 2014-11-14 09:48:27 +01:00 committed by Russell King
parent f560e32295
commit 5670c2a52f
1 changed files with 11 additions and 4 deletions
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15
drivers/amba/bus.c
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@ -95,8 +95,12 @@ static int amba_pm_runtime_suspend(struct device *dev)
struct amba_device *pcdev = to_amba_device(dev);
int ret = pm_generic_runtime_suspend(dev);
if (ret == 0 && dev->driver)
clk_disable_unprepare(pcdev->pclk);
if (ret == 0 && dev->driver) {
if (pm_runtime_is_irq_safe(dev))
clk_disable(pcdev->pclk);
else
clk_disable_unprepare(pcdev->pclk);
}
return ret;
}
@ -107,7 +111,10 @@ static int amba_pm_runtime_resume(struct device *dev)
int ret;
if (dev->driver) {
ret = clk_prepare_enable(pcdev->pclk);
if (pm_runtime_is_irq_safe(dev))
ret = clk_enable(pcdev->pclk);
else
ret = clk_prepare_enable(pcdev->pclk);
/* Failure is probably fatal to the system, but... */
if (ret)
return ret;
@ -115,7 +122,7 @@ static int amba_pm_runtime_resume(struct device *dev)
return pm_generic_runtime_resume(dev);
}
#endif
#endif /* CONFIG_PM */
static const struct dev_pm_ops amba_pm = {
.suspend = pm_generic_suspend,