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()). If such driver
implements its own runtime PM functions then assume it will handle the
runtime PM completely and it will replace our clock handling.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
---
drivers/amba/bus.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index 3cf61a127ee5..38461430b7cf 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -94,9 +94,18 @@ 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)
+ if (ret == 0 && dev->driver) {
+ /*
+ * If driver handles runtime suspend don't duplicate
+ * the work here.
+ */
+ if (dev->driver->pm && dev->driver->pm->runtime_suspend)
+ goto out;
+
clk_disable_unprepare(pcdev->pclk);
+ }
+out:
return ret;
}
@@ -106,12 +115,16 @@ static int amba_pm_runtime_resume(struct device *dev)
int ret;
if (dev->driver) {
+ if (dev->driver->pm && dev->driver->pm->runtime_resume)
+ goto out;
+
ret = clk_prepare_enable(pcdev->pclk);
/* Failure is probably fatal to the system, but... */
if (ret)
return ret;
}
+out:
return pm_generic_runtime_resume(dev);
}
#endif
--
1.9.1
--
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