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Diffstat (limited to 'drivers/amba/bus.c')
-rw-r--r--drivers/amba/bus.c68
1 files changed, 64 insertions, 4 deletions
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index d74926e0939..bd230e80113 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -365,6 +365,40 @@ static int amba_pm_restore_noirq(struct device *dev)
#endif /* !CONFIG_HIBERNATE_CALLBACKS */
+#ifdef CONFIG_PM_RUNTIME
+/*
+ * Hooks to provide runtime PM of the pclk (bus clock). It is safe to
+ * enable/disable the bus clock at runtime PM suspend/resume as this
+ * does not result in loss of context. However, disabling vcore power
+ * would do, so we leave that to the driver.
+ */
+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(pcdev->pclk);
+
+ return ret;
+}
+
+static int amba_pm_runtime_resume(struct device *dev)
+{
+ struct amba_device *pcdev = to_amba_device(dev);
+ int ret;
+
+ if (dev->driver) {
+ ret = clk_enable(pcdev->pclk);
+ /* Failure is probably fatal to the system, but... */
+ if (ret)
+ return ret;
+ }
+
+ return pm_generic_runtime_resume(dev);
+}
+#endif
+
#ifdef CONFIG_PM
static const struct dev_pm_ops amba_pm = {
@@ -383,8 +417,8 @@ static const struct dev_pm_ops amba_pm = {
.poweroff_noirq = amba_pm_poweroff_noirq,
.restore_noirq = amba_pm_restore_noirq,
SET_RUNTIME_PM_OPS(
- pm_generic_runtime_suspend,
- pm_generic_runtime_resume,
+ amba_pm_runtime_suspend,
+ amba_pm_runtime_resume,
pm_generic_runtime_idle
)
};
@@ -426,9 +460,17 @@ static int amba_get_enable_pclk(struct amba_device *pcdev)
if (IS_ERR(pclk))
return PTR_ERR(pclk);
+ ret = clk_prepare(pclk);
+ if (ret) {
+ clk_put(pclk);
+ return ret;
+ }
+
ret = clk_enable(pclk);
- if (ret)
+ if (ret) {
+ clk_unprepare(pclk);
clk_put(pclk);
+ }
return ret;
}
@@ -438,6 +480,7 @@ static void amba_put_disable_pclk(struct amba_device *pcdev)
struct clk *pclk = pcdev->pclk;
clk_disable(pclk);
+ clk_unprepare(pclk);
clk_put(pclk);
}
@@ -494,10 +537,18 @@ static int amba_probe(struct device *dev)
if (ret)
break;
+ pm_runtime_get_noresume(dev);
+ pm_runtime_set_active(dev);
+ pm_runtime_enable(dev);
+
ret = pcdrv->probe(pcdev, id);
if (ret == 0)
break;
+ pm_runtime_disable(dev);
+ pm_runtime_set_suspended(dev);
+ pm_runtime_put_noidle(dev);
+
amba_put_disable_pclk(pcdev);
amba_put_disable_vcore(pcdev);
} while (0);
@@ -509,7 +560,16 @@ static int amba_remove(struct device *dev)
{
struct amba_device *pcdev = to_amba_device(dev);
struct amba_driver *drv = to_amba_driver(dev->driver);
- int ret = drv->remove(pcdev);
+ int ret;
+
+ pm_runtime_get_sync(dev);
+ ret = drv->remove(pcdev);
+ pm_runtime_put_noidle(dev);
+
+ /* Undo the runtime PM settings in amba_probe() */
+ pm_runtime_disable(dev);
+ pm_runtime_set_suspended(dev);
+ pm_runtime_put_noidle(dev);
amba_put_disable_pclk(pcdev);
amba_put_disable_vcore(pcdev);